Development Proposal and Environmental

Transcription

ABN 14 011 062 338
Development Proposal and
Environmental Management Plan
Swift Australia Pty Limited
Proposed Wastewater Treatment Plant – Phase 1
King Island Abattoir
November 2010
Swift
1 Lock Way, Riverview, QLD 4303
T +61 3 93164732
[email protected]
www.jbsswift.com.au
Development Proposal and Environmental Management Plan
Contents
Executive Summary
6
1. Introduction
7
1.1.
Title
7
1.2.
Proponent
7
1.3.
Proposal Summary
7
1.4.
Background
8
1.5.
Legislative Context
9
1.6.
Public Consultation
9
2. Assessment of Alternatives
10
2.1. Disposal options
10
2.2. Treatment options
13
2.3. Summary
16
3. Proposal Description
3.1.
Overview of the proposed Wastewater Treatment Plant
3.1.1.Location
17
17
19
3.2.
Wastewater Composition
19
3.3.
Final Effluent Quality
24
3.4.
Process Description – Abattoir Primary Treatment
25
3.5.
Process Design – Covered Anaerobic Lagoon (CAL)
26
3.6.
Key Design Issues – CAL
28
3.7.
Operational Issues – CAL
32
3.8.
Process Design – Anaerobic & Settling Ponds
33
3.9.
Process Design – Polishing Ponds
37
3.10. Overall Pollutant Removal
38
3.11. Solid Waste Management
39
3.12. Air Emissions (Odour Dispersion Assessment)
40
3.13. Energy Management
41
3.14. Noise Management
41
3.15. Traffic
41
3.16. Construction and Commissioning
42
4. The Existing Environment
4.1.
Planning Aspects
Swift Australia – DPEMP
44
44
2
4.2.
Environment Aspects
44
4.3.
Socio-economic Aspects
47
4.4.
Alternative sites
48
5. Potential Effects and Their Management
49
5.1.
Air Emissions (Odour dispersion)
49
5.2.
Wastewater
50
5.3.
Ground Water
50
5.4.
Noise Emissions
50
5.5.
Solid and Controlled Waste Management
51
5.6.
Dangerous Goods
51
5.7.
Greenhouse Gases and Ozone Depleting Substances
51
5.8.
Visual Effects
52
5.9.
Hazard Analysis and Risk Assessment
52
5.10. Fire Risk
52
5.11. Infrastructure and Off-site Ancillary Facilities
52
5.12. Environmental Management System
52
6. Monitoring and Review
53
6.1. Effluent Discharge Monitoring
53
6.2. Groundwater Monitoring
54
6.3. Reporting Requirements
54
7. Commitments
55
8. Conclusion
56
9. Abbreviations
57
10. References
57
3
Table Index
Table 1
Qualitative assessment of disposal option against salient criteria
11
Table 2
Assessment of treatment Options
13
Table 3
Design Wastewater Composition
20
Table A3.1
Results of composites taken over the whole processing day, July 2010
21
Table A3.2
Results of composite grab samples taken of DAF feed during May-June 2010
21
Table A3.3
Results of composite grab samples taken of DAF feed during May-June 2010
22
Table A3.4
Results of composite grab samples taken of DAF discharge during May-June 2010
22
Table A3.5
Statistics for DAF treated samples in table A3.1
23
Table A3.6
Removals by DAF from May-June average values
23
Table 4
Expected average treated effluent composition
24
Table 5
Removal of Pollutants in DAF
26
Table 6
Design parameters for the Covered Anaerobic Lagoon
28
Table 7
Design parameters for the Aerated & Settling Ponds
34
Table 8
Design parameters for the Polishing Ponds
38
Table 9
Design pollution removal across the pond system
38
Table 10
Solid Waste Description
39
Table 11
Energy Using Apparatus
41
Table 12
New wastewater treatment plant potential odour sources
49
Table 13
Wastewater Monitoring
54
Table 14
Commitments
55
Figure 1
Proposed Wastewater Treatment Plant Flow Chart
18
Figure 2
Location of King Island Abattoir facility - overview
19
Figure 3
Location of King Island Abattoir facility – close up
19
Figure 4
Bio-gas Flare Design
31
Figure 5
17mm Heavy Bird Netting
35
A1
Design Drawing – Site Boundary
58
A2
Design Drawing - WWTP
59
A3
Design Drawing – Elevation
60
B1 & B2
Design Drawing – Bird Netting
61
Figure Index
Appendices
4
C1-C4
Project Plan
63
D
DPEMP Project Specific Guidelines
67
E
Certificate of Title
72
F
RENOIR Settling Data
75
G
7.5kW Aerator specification
76
H
5.5kW Aerator specification
79
I
Heritage Report
82
J
Biogas Monitoring
84
K
Climate Date
86
L
Odour Dispersion Assessment
87
M
Soil Test Pit (1-3) Results
119
N
Expected Acoustical Impact of New Aerators and Flare
122
Document History and Status
Version
1
2
3
Date
Reviewer
30 March 2010
29 September 2010
9 November 2010
Status/Comment
Draft for Swift / EPA Review
First Final Draft to submitted to EPA
Final Report to EPA / Public Comment
Originator
Project Manager
Troy White
Troy White
Troy White
Troy White
Troy White
Troy White
5
Executive Summary
Introduction
This Development Proposal and Environmental Management Plan (DPEMP) has been prepared for the
purpose of constructing and commissioning a Covered Anaerobic Lagoon (CAL) followed by Aerated /
Facultative Lagoons to treat wastewater generated from the site abattoir on King Island. This DPEMP is
also intended to assist EPA Tasmania complete its assessment process, allow public review and
comment that will facilitate the development of permit conditions.
Process Description
Swift Australia is proposing to upgrade the wastewater treatment system at its King Island abattoir site.
The proposed system is designed to treat 260 KL/day (Mon-Fri) through and initial solids screen prior to
entering a 2.3ML CAL to reduce the organic loads and where the captured Biogas is flared providing
odour and GHG reductions. The wastewater enters the adjacent 2ML aerated pond where additional
organic load reduction occurs prior to flowing through a series of new settling ponds, removing the
suspended solids. The wastewater then enters a series of final polishing ponds that also has the facility to
increase the dissolved oxygen levels via a small surface aerator prior to off site release. All lagoons /
ponds will be fully lined with 1.5mm HDPE liners except in the Aerated sections where 2.0mm HDPE
liners will be used.
Exiting Environment
The proposed site is located adjacent to the abattoir on the existing title. The site has been selected to be
the most suitable due to the proximity and gentle topography of the area. Historically, this area has been
subject to year round cattle grazing and subsequently there has been no evidence of threatened flora or
fauna on the proposed site. The location of the proposed WWTP to the King Island Airport is within close
proximity and has been designed with this in mind. There is expected to be no impact on the ground
water as a result of the pond designs incorporating HDPE liners.
Potential Effects and their management
The potential effects of the proposed wastewater treatment system are expected to be a positive impact,
with identified impacts discussed and mitigation measures developed. Specifically, the close proximity of
the King Island Airport highlighted the potential issues of bird attraction (bird strike). This has been
addressed by fully enclosing all open ponds with bird netting.
Monitoring and Review
The monitoring and review program has been established to ensure the management prescriptions
described in the DPEMP project specific guidelines (Appendix B) set out by EPA Tasmania are
successfully complied with. The key aspects requiring monitoring will be final wastewater quality and
odour emissions.
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1.
Introduction
1.1.
Title
Swift Australia Pty Limited (Swift): Wastewater Treatment Plant - Phase 1 King Island Abattoir and
Rendering plant
1.2.
Proponent
The proponent of the proposed WWTP is Swift Australia Pty Limited:
Swift Australia Pty Limited (ABN: 14 011 062 338)
1 Lock Way
Riverview
QLD 4303
The contact for this project is:
Troy White
Phone: 03 9316 4732
Email: [email protected]
1.3.
Proposal Summary
Swift propose to establish an anaerobic and aerobic / facultative WWTP at the King Island Abattoir,
Morrison Avenue, Loorana, King Island 7256.
The objective of the proposed WWTP is to improve the treatment of existing wastewater generated on
site. The facility will address environmental concerns, in particular odour, aviation bird strikes and
facilitate the cessation of discharge to Porky Creek by 31 December 2012, subject to local land owner
consent and future EPA DPEMP approval of Phase 2 – Ocean Outfall. The facility is being designed to
accommodate a throughput of 260 thousand litres (260 KL) of wastewater per day.
This facility is estimated to cost $1.1 million to construct.
7
1.4.
Background
King Island has a population of approximately 1300 residents. There are about 85,000 head of cattle on
the island being 30% Dairy and 70% Beef. The King Island Abattoir facility was originally built by the
Tasmanian Government in the 1950’s. R.J.Gilbertsons later purchased the very basic abattoir from the
Tasmanian Government in the late 1980’s. Very little money had been spent on the plant; it had no export
license and was in poor shape. Gilbertsons started operations and loaded ¼ sides of beef into DC3’s at
the side fence direct to the airstrip beside the plant, shipping them for processing at their Victorian plants.
In 1990 the company realised the potential of the King Island name and started to produce, and promote
our great King Island brand.
JBS (Brazil) or Swift Australia Pty Ltd (Swift) purchased Australian Meat Holdings in July 2007. In May
2008, Swift acquired the Tasman Group Services business which includes the King Island site. The site
employs 85 people whom process approximately 180 head of cattle per day, 48 weeks per year. Swift
have 10 Abattoirs throughout Australia, with the King Island site contributing to approximately 1.6% of the
weekly beef processing capacity. Swift has since grown to be the largest red meat producers in Australia
investing in over $150M in capital improvements during this period. At Swift we believe our company is
close to nature and we work to do all things in a sustainable and environmentally-friendly manner. Swift is
committed to recycling waste; reducing energy and water consumption; and Greenhouse gas reductions.
In 2009, soon after a viability study, Swift made the decision to close the King Island site. Subsequently,
Swift engaged the Tasmanian Government and negotiated a loan agreement. This loan agreement was
contingent on obtaining EPA approval of Swift developing an acceptable Wastewater Management
Strategy. Swift is also committed to delivering operation improvements over and above the proposed
WWTP subject to this DPEMP. These improvements are as follows;
•
Spray Chilling of carcasses;
•
Green offal recoveries in the form of Omasum tripe, Honeycomb tripe, Mountain chain tripe,
and small intestines;
•
Renewal and upgrading of refrigeration infrastructure, with new compressor technology,
new condensing equipment, additional blast freezing capacity, additional carton handling
and lead-out capacity, installation of hot gas defrost systems on evaporators – removing
need for water defrosts;
•
Installation of chilled lidding equipment to promote King Island brand and improve
marketability of products;
•
Replacement of some aged equipment;
•
Proposed additional water supply from Currie racecourse bore;
•
Energy efficiency improvements with heat loss reductions with application of insulation and
cladding;
•
Energy heat recovery improvements from waste heat recovery from cooker vents;
•
Improvements and overhauls of odour treatment biofilter for rendering odours;
8
•
Rebuild/replacement of aged infrastructure including carton blast chillers, water tanks, and
some other equipment;
•
1.5.
Breeding and stock management assistance for King Island farming sector.
Legislative Context
This proposal was referred to the Environment Protection Authority (EPA) Board in the form of a Notice of
Intent (NOI) in July 2010. The Director of EPA responded to the NOI (dated 23 July 2010) declaring the
proposal to be a Level 2 activity under the Environmental Management and Pollution Control Act 1994
(EMPCA) (see Appendix A).
As a Level 2 activity the proposal requires approval from the EPA Board. Approval is also required from
the King Island Council under the Land Use Planning and Approval Act 1993 (LUPAA). These two tiers of
assessment are undertaken concurrently and relate to different aspects of the project.
No matters of National Environmental Significance have been identified as relevant to this project and
hence referral under the Commonwealth’s Environmental Protection and Biodiversity Conservation Act
1999 (EPBCA) is not considered to be required by Swift.
The proposed development will also have to comply with a broad range of environmental and planning
legislation, guidelines, standards and policies. The details of such documents are outlined through the
relevant sections of this DPEMP.
1.6.
Public Consultation
In preparing this DPEMP, Swift has pro-actively engaged with the local and state authorities and the local
community. State and local elected representatives have expressed support for the proposal, subject to it
meeting the required environmental and planning requirements.
Swift has directly engaged with neighbours of the King Island site to explain the proposal and receive
feedback. Contact with the local residents was made in person (direct ‘doorknocking’) and will be followed
up by advertisement in the daily paper. The outcome of the initial consultation process determined that all
respondents were not concerned about the proposed upgrade at the King Island Abattoir. Many
residences acknowledged that the facility has been operating in its current state for about 60 years and
couldn’t understand why such a large scale WWTP upgrade was required. Swift communicated the
overall environmental improvements and benefits of the proposed upgrade that will contribute to the
ongoing viability and success of the King Island Abattoir operations.
9
2.
Assessment of Alternatives
In Section 2.1, various alternate disposal routes are evaluated and the reasons for the final selection
of ocean discharge explained. In Section 2.2, three treatment alternatives are described and assessed.
2.1.
Disposal Options
The various studies conducted regarding upgrading of the King Island abattoir effluent have generally
considered four options for the ultimate disposal or reuse of the treated effluent. These are:
•
Release to Porky Creek (the existing situation). This is not considered to be a viable long term
solution by EPA;
•
Reuse by land application;
•
Reuse within the abattoir facility;
•
Release to Bass Strait via ocean outfall.
A further option considered is sub-surface injection.
The critical determinants of the environmental, technical and commercial viability of each of these options
are considered in Table 1 and further comment is provided below.
2.1.1.Porky’s Creek
Porky’s Creek has been the receiving environment for the abattoir effluent for approximately 60 years.
EPA considers continued discharge to this creek unacceptable, especially since it is an ephemeral stream
with negligible natural flow in summer. The high nutrient and salt level in the treated wastewater suggest
that in the absence of any natural flow, there is insufficient mixing zone in the Creek to assist with
discharge in summer.
2.1.2.Land Reuse
Land reuse of treated effluent is the final destination for the majority of meat processing facility effluents in
Australia and in many instances provides some return through cropping. Usually high land areas are
required and these are typically defined by nutrient loading limitations. Depending on climate, some wet
weather storage volume may also be required – typically 1 – 3 months of water storage.
On King Island, the opportunity to irrigate treated wastewater is poor for a number of reasons identified in
Table 1. These include:
•
Wet climatic conditions. Annual evapotranspiration averages of the order of 1,020 mm compared
to an average rainfall of 854 mm. In the average wet year, six months (April – September) of the
year have rainfall higher or similar to evapotranspiration (Appendix K). Approximately 37 ha
10
would need to be irrigated to manage the annual 61 ML of wastewater (and nutrient loads would
suggest that even more land area would be needed).
Table 1. Qualitative assessment of disposal options against salient criteria
Cri
Disposal Option
Criterion
Porky’s Creek
Ocean outfall
Land reuse
Reuse in abattoir
Unsuitable in
long term
Acceptable
Unsuitable. SAR
of 34
Unsuitable chloride
of
1,800 mg/l
Capacity to receive
full flow
Unsuitable
Acceptable
Summer only
Risk to Groundwater
Low - moderate
Negligible
Very high
Negligible
Risk to Aquatic flora
& fauna
Moderate
Low after dilution
Negligible
Negligible
Effluent salinity
Only 10 – 20%
subject to quality
issues
Sub-surface
injection
Unsuitable
Summer only
Extreme
Low
The 2009 year was a 9th percentile wet year (980 mm rain) and on a monthly water balance basis almost
140 ha of land would have been needed for appropriate application (hydraulic balance basis only). At
about $10,000/ha to fit out, the average wet year land requirement of 40 ha amounts to $400,000 fit out
costs not including the pipeline to supply the irrigation headers.
•
The wet winter climate would require 6 months water holding capacity (30 ML) so that winter
volumes can be held over until a positive soil water deficit for irrigation was available in soils
(typically in October). This is of the order of $400,000 to construct with the installation of
impermeable linings. The shallow water table would limit the depth of this storage and require a
large land area to be dedicated to this purpose.
•
The effluent has a very high Sodium Adsorption Ratio (SAR) of ~ 34. This is probably mainly due
to a combination of brine from the hide shed leaking into the wastewater and regenerate from the
water conditioning resins.
•
The groundwater is shallow and depended on by the Island community.
•
Finally, due to the high nutrient level in the treated effluent, it would be necessary to grow crops
for nutrient export, rather than graze an irrigated pasture (otherwise land areas required become
infeasible). There is little demand on the island for crops and this practice would to some extent
cannibalise land used to grow the animals on which the abattoir depends.
For these reasons, land reuse is not considered commercially and technically viable.
2.1.3.Reuse in Abattoir
Currently King Island abattoir sources its incoming water from four groundwater bores. Available
measurements of bore quality indicate high quality water with relatively moderate TDS and sodium levels.
11
The opportunities and legality of recycling treated water in export meat facilities was actively considered
by the industry during the severe drought in South East Queensland during the early 2000s. AQIS issued
a formal Meat Notice2 which encouraged water reuse, but unless water is rehabilitated to extremely
stringent standards (typically including reverse osmosis), it is not possible to accept it for food contact. US
regulations further require stringent separation of all human wastes from the treatment system.
Consequently, effluent treated to secondary standard may be recycled for use in non-potable
applications, including cattle yard washing, cattle washing (excluding final rinse) and other suitable
applications (e.g. wastewater screen sprays). Unfortunately, this is rarely more than 20% of total water
consumption where feedlot cattle are not being processed.
A further consideration is corrosion. The typical chloride levels in the treated water are high (1,800 mg/l).
This exceeds safe levels for most stainless steels (304, 316 grades), which suffer severe pitting at these
concentrations. The recycling of the treated water will need to consider this issue to minimise
maintenance costs.
In summary, recycling of water at King Island abattoir is not a suitable final use for more than about 20%
of water flows. Most of the treated effluent needs discharge to a suitable receiving environment.
2.1.4.Sub-Surface Injection
In some parts of Australia, treated water is injected into sub-surface aquifers, where it can be accessed at
later periods if required. The water quality needed to permit this is not technically or economically feasible
to deliver from abattoir wastewater due to the high initial nutrient and salt levels in the raw effluent and the
dependence of the Island community on the groundwater resource.
This option was considered not viable.
2.1.5.Ocean Outfall
The discharge of treated effluent into Bass Strait via the ocean outfall presents the most favourable
outcome to that of the existing outfall via Porky Creek. The local environment in the vicinity of the outfall:
•
Will provide a an adequate mixing zone all year round due to consistent winds from the Southern
Ocean, large ocean waves (rarely less than 1m height on the west coast) and strong ocean
currents.
•
is unlikely to be impacted by the high salinity of the effluent;
•
poses negligible threat to groundwater supplies;
•
provides the most practicable and technically feasible solution commensurate with protecting
environmental values.
The main challenge is the high nutrient levels in the treated discharge (Section 3.3 -Table 4).
12
Due to the loss of ammonia nitrogen, by volatilisation in the polishing ponds, it is expected that nitrogen
levels will be considerably less in summer (when their discharge into the ocean might be expected to be
more biologically stimulatory due to warmer ocean temperature). In winter, the cold ocean temperatures
assist in diminishing the impact of the higher nitrogen level, especially in the near field of the outfall
diffuser.
Previous investigation into ocean outfall performed by CEE in 2009 using data extracted from the Bureau
of Meteorology ocean wave model that under typical wave and current conditions, this report estimated
that an initial dilution of 1:50 would be produced within 20 m of the diffuser, and 100:1 within 50 m. This
zone of initial dilution is expected to permit the discharge to fall within the State Policy on Water Quality
Management 1997, Emission Limit Guidelines for Sewage Treatment Plants; that discharge pollutants
into fresh and marine waters (see Section 3.3 -Table 4). In summary, ocean discharge represents the
best option for King Island abattoir.
2.2.
Treatment Options
For treatment of abattoir wastewater for non-trade waste discharge disposal option, the following two
treatment trains are typically used:
•
Anaerobic ponds with downstream Sequencing Batch Reactor (most commonly) or other type of
activated sludge plant;
•
Anaerobic pond(s) with downstream aerated pond with subsequent sludge settling and polishing
ponds.
The features of these treatment alternatives are contrasted in Table 2.
Table 2: Assessment of Treatment Options
13
2.2.1.Anaerobic Ponds
Anaerobic ponds are best practice first stage biological treatment for meat processing effluent unless land
3
area is constricted . It is included in each of the treatment alternates in Table 2.
Most anaerobic ponds in meat plants in Australia have been installed without synthetic covers, since the
effluent typically contains sufficient fats and fine cellulosic material which form a natural floating crust.
There has been a reluctance to adopt the covered pond technology (CAL) due to a history of technical
issues which are caused in part by the propensity of the effluent to form a corrosive fatty acid layer under
the covers and/or crusts that block gas mains and/or discharge pipes. This was the subject of a recent
Meat & Livestock Australia (MLA) report4. However, recently the contribution of synthetic covers to odour
and carbon emission control and the potential for high energy biogas capture has made the technology
more attractive.
Johns Environmental has twenty years experience in the design of anaerobic ponds for meat plants. In
the past two years, the company has:
•
Designed twin 30 ML covered anaerobic ponds for Cargill Wagga Wagga beef processing plant
(currently under construction);
•
Assisted in the start up of the 20 ML covered anaerobic pond installed at AJ Bush & Sons at their
rendering facility in Beaudesert, QLD. The pond is now operating successfully.
•
Designed a 10 ML covered anaerobic pond for AJ Bush Riverstone rendering plant (awaiting
approvals).
Nevertheless, the covered anaerobic lagoon technology applied to meat processing effluent remains an
emerging technology with significant uncertainties regarding longevity and operational risks. The design
proposed for King Island is designed to mitigate these risks to the fullest extent possible with current
knowledge.
2.2.2.Alternate disposal Option 1: CAL & SBR
The use of activated sludge treatment using the Sequencing Batch Reactor (SBR) variant for COD and
nitrogen removal to low levels is now well established in the industry. Swift Australia have successfully
operated twin 10 ML SBRs since the mid 90s at their large Dinmore facility in Brisbane. However in the
setting of King Island, SBR technology is inappropriate for the following reasons:
•
It is technically complex to operate, especially where expert advice is distant;
•
It has a high energy intensity (Table 2), partly driven by the need to achieve the required oxygen
input within 50 – 65% of the cycle time and also by the high nitrogen loads typically present in
modern integrated abattoirs with rendering plants. For comparison, modern STP BNR plants
operate at about 500 kWh / ML due to their low feed nitrogen levels. On King Island, the high cost
of electricity makes this technology highly expensive to operate.
14
•
It requires high maintenance and monitoring inputs to ensure that the system is properly
controlled to achieve compliance with discharge limits. Regular sludge wasting, its dewatering
and disposal are significant issues.
Consequently, this technology was not adopted by the engineering team.
2.2.3.Alternate Disposal Option 2: CAL & Aerated & Polishing Ponds
The discharge from the CAL contains a design BOD5 concentration of 450 mg/l. Stabilisation of this level
requires significant oxygen input if odour generation is to be minimised. For this reason an aerated pond
equipped with surface aeration is sensible. This pond:
•
Is technologically straightforward and robust to operate;
•
Guarantees sufficient oxygen input to stabilize the incoming organic load;
•
Rapidly mixes the incoming anaerobic effluent into the whole pond to minimise formation of
offensive odours, which can occur in non-aerated facultative ponds downstream of anaerobic
ponds.
•
Ensures intimate contact of the biological floc with the available organic load through sufficient
mixing energy to maximise degradation rates.
The main challenge for aerated ponds is managing the quantity of bacterial floc formed. If allowed to
simply exit to downstream maturation or facultative ponds, the bacterial floc settles out and can fill the
downstream pond with settled sludge. This can become odorous and reduce treatment efficiency over
time.
Active management of this sludge is recommended in modern installations. The most common means of
this is to:
•
either dedicate the downstream pond to simply fill with sludge in a manner that protects
subsequent ponds. This leaves an expensive legacy in that the pond will eventually require
desludging, which is an expensive and time consuming process.
•
or provide a downstream settling pond with an active sludge management system. This has been
successfully operated in technologies such as the RENOIR pond, designed by Johns
Environmental and operated successfully since 2003 at Harvey Beef, WA. The settle zone of the
RENOIR pond is a protected area in which the aerated pond discharge enters in a laminar
manner with sludge separating from the treated effluent and settling in the base of the zone. From
there, a sludge pump equipped with floor-mounted extraction piping removes the settled material
from time to time as required. The discharge from the settle zone has TSS levels at least an order
of magnitude less than the aerated pond basin (Appendix D).
15
Downstream polishing ponds can then focus on disinfection and further polishing of the effluent through
the combination of long detention times in a weakly alkaline, highly oxygenated and solar irradiated
aqueous environment.
This is the preferred design for King Island abattoir.
2.2.4.Alternate Disposal Option 3: CAL & Aerated Pond & Wetlands
An alternate technology to the final polishing ponds is the use of constructed wetlands. In this option the
water exiting Polishing Pond 1 enters the wetlands for treatment. Recommended HRTs for wetlands
treating dilute effluent is of the order of 5 days. Coupled with a typical average depth of 0.5 – 0.6 m, this
requires a constructed wetland of approximately 0.25 ha surface area.
The Currie Township commissioned a wetland system in November 2005 to polish its sewage prior to
discharge. In considering and rejecting this option, the engineering team noted:
•
The wetland has a 43% larger footprint than Polishing Pond 2 in the preferred option.
•
Estimated costs for constructed wetlands are about $500 – 750,000 per ha and would be even
higher on King Island. The estimated cost would be at least 4-fold more than a straightforward
polishing pond (which has 3 times the treatment volume).
•
Wetlands have not been widely applied to meat processing effluent in Australia and significant
technical risk would apply, especially in regard to wetland plant sensitivity to high ammonia levels
relative to sewage. Further, they rarely achieve consistently superior treatment outcomes to
polishing ponds, except perhaps for TSS.
•
Controlling bird access to the wetlands to minimise risk of bird strike at the airport would be more
difficult than for polishing ponds. The bird netting recommended for the latter could not be readily
applied to wetlands with its tall aquatic plants and their need for sunlight to thrive.
•
Finally, there are substantial maintenance issues with wetlands due to their diverse and dynamic
nature. They are vulnerable to clogging and overgrowth, both of which are difficult to detect other
than by failing performance and challenging to fix.
2.3.
Summary
In summary, the only feasible disposal route open for consideration is the ocean outfall. Other options
cannot feasibly handle the quantity of treated water discharged.
The CAL – ponds treatment option has the optimal capital and operating cost consistent with required
final effluent quality. Other options are substantially more expensive to construct and are either expensive
and or complex to operate (Section 2.2.2 Option 1 CAL + SBR), or pose increased risks in terms of
technical implementation and potential bird strikes at the adjacent airport (Section 2.2.4 Option 3, CAL +
ponds + wetland).
16
3.
Proposal Description
3.1.
Overview of the proposed Wastewater Treatment System
A process flow diagram outlining the proposed wastewater treatment system is provided in Figure 1.
Key features of the proposed system include:
•
For the abattoir wastewater, the primary treatment remains largely the same as currently exists,
except that the obsolete Dissolved Air Flotation (DAF) plant is taken out of service. The paunch
stream continues to receive treatment through the FAN screw press, which is state-of-art for this
stream. The various waste streams are then combined and screened through the existing DODA
rotary screen to remove gross solids and reduce TSS levels.
•
The screened combined wastewater is discharged by gravity into a new 2.3 ML nominal Covered
Anaerobic Lagoon (CAL). This pond removes organic matter (BOD, COD) using anaerobic
bacteria to generate methane-rich biogas which is captured by the synthetic cover over the pond.
The biogas and associated odorous compounds are collected and combusted in an adjacent
biogas flare. This destroys odour and climate-warming methane. The CAL is designed to be
highly active all year round – in large part due to the elevated operating temperatures (30 –
35oC). This ensures that much of the new excess biomass generated is discharged into the
downstream aeration pond, rather than settle out in the CAL.
•
The CAL discharge flows into the adjacent new aeration pond (2 ML nominal) via a submerged
inlet to minimise odour release. In the aeration pond, aerobic bacteria further reduce the BOD
concentration to generate effluent that is expected to have negligible odour. The contents are
completely mixed by low speed surface aerators.
•
The Aeration Pond discharges via a series of pipes into the new Settlement Pond (nominal
volume of 0.7 ML). Since the aeration pond generates significant levels of bacterial floc as
suspended solids, the task of the Settlement Pond is to remove these by settling. The pond is
equipped with two sludge removal pipes near the pond base, from where accumulated sludge
can be removed as required.
•
The treated effluent then flows out of the Settlement Pond into two Polishing Ponds in series.
These ponds provide additional retention time to encourage disinfection of the effluent from the
combined action of sun, wind and pH, reduce organic levels further and to permit some
volatilisation of ammonia nitrogen, especially during summer. Prior to discharge from Polishing
Pond 2, a small surface aerator ensures that the dissolved oxygen levels are high prior to delivery
to Porky Creek.
•
Some effluent from Polishing Pond 2 may be used for non-potable uses around the facility as
permitted.
•
Phase 2 of the upgrade (subject to separate DPEMP) is expected to see the installation of a 4 km
effluent pipe transferring effluent to the ocean outfall upon project design and approvals obtained.
17
More detailed process description is provided in the following sections. The treatment system is designed
to provide a robust, cost effective system requiring a minimum of operational effort and electrical and
chemical consumption to generate treated effluent suitable for odour-free disposal.
18
19
3.1.1.Location
The WWTP will be located at Morrison Avenue, Loorara, King Island approximately 7 km north of Currie
(see figure 1), adjacent to the airport. (Refer in Figure 2 – Arial Map)
Above: Figure 2 – Arial map showing location of site, residence and king Island Airport
Location Abattoir site (Figure 2)
King Island Airport (Figure 2)
Proposed WWTP site (Figure 3)
Above: Figure 3 – Close up of proposed site
3.2.
Wastewater Composition
The wastewater stream design composition post DODA screen and DAF and prior to pond treatment are
provided in Table 3. These design values are derived from testing conducted by Swift Australia during
May – July 2010 with samples analysed by EML (Melbourne).
20
Table 3: Design wastewater composition
Parameter
Total COD
BOD5
TSS
O&G
TN
Ammonia-N
TP
TDS
Calcium
Magnesium
Sodium
Chloride
Sulphate
SAR (calculated)
EC
Temp
pH
Faecal coliforms
Units
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
μS/cm
oC
#/100 ml
7,250
3,000
2,000
120
450
250
45
5,200
115
20
1,500
1,800
65
34
8,500
30 – 35
7.2
2 E+06
Some observations pertinent to the pond system design include:
1. The wastewater temperature is warm and optimal for anaerobic treatment. The provision of a
synthetic cover on the anaerobic pond ensures that the pond will operate at this temperature year
round, which permits elevated rates of biological activity, The warmth anaerobic effluent also
means that the water temperature in the first aerated pond cell will also be warmer than ambient
water during winter by a small, but significant degree.
2. Oil & grease (O&G) levels are low relative to the rest of the wastewater composition. This is not
due to the operation of the existing DAF, which achieved only moderate O&G removal (~ 50%). It
is thought that the low O&G levels are due to the down-rated production speeds at King Island.
3. Nitrogen and salt (TDS, sodium and chloride) levels are elevated relative to industry norms. The
reasons are unclear. The elevated salt levels are well within the tolerance of anaerobic and
aerobic biological systems.
4. Other parameters are within normal ranges for integrated beef processing facilities.
Suitable data describing the physicochemical characteristics of the King Island abattoir wastewater were
obtained via a series of grab and composite samples taken by King Island personnel and sent for analysis
to EML laboratories in Melbourne. The data presented represent:
•
Table A3.1: Results of composites taken during processing on 2 days in July 2010.
•
Tables A3.2 & 3: Results of composite grab samples taken of DAF feed during May-June 2010;
•
Tables A3.4 & 5: Results of composite grab samples taken of DAF discharge during May-June
2010;
•
Table A3.6: Reports average removal of contaminants over the DAF.
21
Table A3.1. Results from effluent composite samples taken over the whole processing day, July 2010.
Table A3.2. Results from effluent composite samples taken from the DAF feed during May - June 2010.
22
Table A3.3. Statistics for Pre-DAF samples in table A3.2.
Table A3.4. Results from effluent composite samples taken of DAF treated effluent during May - June
2010
23
Table A3.5. Statistics for DAF treated samples in table A1.4.
Table A3.6. Removals by the DAF from May-June average values
Note: Negative values were assigned zero removal
3.3.
Final Effluent Quality
The best estimate of design final effluent quality is presented in Table 2. These values do not constitute a
guarantee of final performance, since there is significant influent variation relating to most parameters and
the pond system performance is subject to seasonal variation. The pond system design seeks to provide
a final effluent with the following properties:
1. Meet maximum emission limits for marine waters allowing for a 1:100 mixing zone dilution;
2. Odour-free after treatment and during storage in the final polishing dam;
3. Permits discharge via the ocean outfall with no visible scums, slicks or colour.
24
Note that the process design assumes that ocean outfall remains EPA Tasmania preferred disposal route
for the treated effluent. There is no attempt made to treat effluent to very low levels associated with high
quality reuse or land irrigation.
Table 4. Expected average treated effluent composition
Parameter
BOD5
TSS
Oil & Grease
Total Nitrogen
Ammonia-N
Total
Phosphorus
Thermotolerant
coliforms
pH
Note:
Units
Final pond quality
After mixing zone
Maximum
Limit
Summer
Winter
Summer
Winter
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
20
100
<10
280
250
40
40
100
<10
400
350
40
0.2
1
<1
2.8
2.5
0.4
0.4
1
<1
4
3.5
0.4
20
30
10
15
5
5
cfu/100
ml
-
1,900
1,900
20
20
750
6.5 – 8.5
6.5 – 8.5
6.5 – 8.5
6.5 – 8.5
6.5 – 8.5
1. “Final pond quality” reflects the quality of the discharge from Polishing Pond 2;
2. “After mixing zone” allows for a 100:1 dilution in the mixing zone at the outfall discharge.
3. “Maximum limit” is taken from the State Policy on Water Quality Management 1997, Emission
Limit Guidelines for Sewage Treatment Plants; that discharge pollutants into fresh and marine
waters.
The design Total Nitrogen level in the raw wastewater is 450 mg/l (Table 3), most of this is converted to
ammonium in the CAL. The estimated final treatment ammonia levels (table 4) have been derived by
assuming a 11% loss in various mechanisms, mainly sludge deposition during winter; a further 27%
volatilised during summer via higher wastewater temperatures, pH and wind action.
As detailed in Section 2, Assessment of Alternative treatment options determined that biological nitrogen
removal via SBR was to complex and costly for King Island; as to Ammonia stripping by lime addition / pH
adjustment. Thus, dilution was accepted as the best means of disposal.
3.4.
Process Description – Abattoir Primary Treatment
The existing abattoir pre-treatment system comprises three pieces of equipment.
3.4.1.FAN Screw Press
The FAN screw press is increasingly applied to dewater wet and dry dumped paunch solids for beef
processing plants. It has proven to be a reliable an robust technology for this purpose provided large and
hard gross solids are removed first. At King Island abattoir, this is done by settling of these solids in the
pre-screw press tank. There are no plans to alter this infrastructure.
25
3.4.2.DODA Screen
The DODA rotary screen currently removes gross and suspended solids from the combined waste
streams. It appears to perform this task well. The screen will be moved from its current location to a new
position immediately adjacent to the CAL. The screened solids are retrieved and land spread.
3.4.3.Dissolved Air Flotation (DAF) Unit
The existing DAF is a circular device of obsolete design for meat industry wastewater. Sampling
performed during May and June 2010 found that removals of key pollutants over the DAF were poor
(Table 5). Oil & grease removal was calculated to be approximately 50%, in part the low removal is
possibly due to the low levels of this pollutant in the wastewater.
The initial intention was to upgrade this unit to improve its performance. Subsequent work to better
characterise the raw wastewater suggests that this is unnecessary. The average oil & grease
concentration in the wastewater is 180 mg/l (pre-DAF). At an average flow of 0.26 ML/day, the influent
O&G load is less than 50 kg/day.
Table 5: Removal of Pollutants in DAF
Parameter
Removal
COD
15%
BOD5
0%
TSS
11%
O&G
53%
The best performance expected from a DAF treating warm abattoir wastewater is a final O&G level in the
treated effluent of about 100 mg/l. Consequently there is little likelihood of improved operation even with a
completely new unit.
The raw influent O&G load amounts to 50 kg/day, or about 60 litres of fat/day. This is equivalent to a layer
of 0.05 mm across the surface of the CAL. It has been determined that this level of O&G is not a threat to
the integrity of the CAL, especially given the low organic loading of the pond. Operation of the CAL will
include dosage of lipase enzyme treatments to control fatty crust accumulation (See Section 3.7.2).
3.5.
Process Design – Covered Anaerobic Lagoon (CAL)
This section describes the design basis for a new covered anaerobic lagoon. This pond is designed to
achieve cost-effective, low energy treatment of the high organic concentrations in the raw wastewater.
Anaerobic ponds represent best practice technology for meat processing wastewater and are widely
26
applied throughout the world and Australia for this purpose. They can cope with large variations in flow
and concentration with minimal reduction in performance.
It is intended to construct a synthetic cover over the CAL. This technology is still relatively new for meat
processing anaerobic ponds in Australia, but is increasingly being adopted. The technology has been
used in Australia by other industries for approximately 25 years. The advantages of a covered (synthetic)
pond include:
•
Negligible odour footprint since odorous gases are captured and combusted in the biogas flare.
•
Performance of the pond is not impacted by the cover;
•
Significant scope 1 greenhouse emissions resulting from methane-rich biogas production are
eliminated by combustion of the gas in the flare;
•
Option to capture and utilize the energy-rich biogas once flow rates and biogas quality are known.
The energy captured would power the wastewater treatment system electrical requirements.
3.5.1.Location of CAL
The CAL will be constructed on the eastern boundary of the abattoir property and to the east side of the
aerobic ponds. The close proximity of the CAL to the abattoir buildings is possible due to the use of the
cover.
3.5.2.Mode of Action
In the anaerobic pond, anaerobic bacteria break down the complex compounds in the wastewater in the
absence of oxygen to release carbon dioxide and methane as the main products of decomposition in
addition to a small increase in bacterial numbers. These products are gaseous and are released to
atmosphere. Sludge production is 10 – 20% that of equivalent aerobic treatment and tends to escape as
elevated suspended solids in the dam discharge. For this reason sludge wasting from the CAL should be
unnecessary.
3.5.3.Process Design Parameters
Key design parameters and dimensions for the CAL are given in Table 6. The dam is suitable for handling
the design abattoir flow and remains at the lower end of usual industry design values for these types of
ponds with an average Hydraulic Retention Time (HRT) of 12 days and a volumetric BOD loading rate of
0.24 kg/m3/day. These values are calculated on a 7-day basis which allows for the fact that there is
negligible weekend load since the abattoir only operates week days. These design values are based on
the pond working year-round at water temperatures between 30 – 35oC (see Table 3).
A minimum removal performance of 85% BOD removal should be achieved. This ensures that the organic
load on the downstream ponds is minimised. This ensures that the risk of odour release and aerobic
sludge formation is kept as low as possible commensurate with normal operation.
27
Table 6: Design parameters for the CAL.
Parameter
Units
Design
Design Flow
kL/day
260
BOD load
kg/d
780
COD load
kg/d
2,000
Pond depth (TWL)
m
5.0
Wall batter
w:h
2.5
Pond area TWL
m2
1,200
Pond Volume (TWL)
m3
2,300
Design HRT
d
12
BOD5 Areal loading
kgBOD/ha.d
7,500
Volumetric loading rate
kgBOD/m3.d
0.24
Design BOD removal
%
85
BOD exit
mg/l
450
BOD load out
kg/d
117
Freeboard (above TWL)
m
0.5
Notes: HRT & loading rates are given on a 7-day basis (e.g. allowing for negligible weekend load).
TWL – top water level; HRT – hydraulic retention time.
3.6.
Key Design Issues
3.6.1. Odour Minimisation
The provision of a synthetic cover across the top water surface of the CAL will ensure that any odorous
emissions are captured and combusted in the associated biogas flare. Odour emissions from the CAL
can be expected to be negligible. This is important, since otherwise prevailing winds from the westerly
quadrant would potentially carry odours across the facility and the adjacent airport.
3.6.2.Inlet/Outlet Structures
Healthy anaerobic ponds treating meat processing wastewater are generally well-mixed due to the large
gas volumes generated through organic breakdown. Stratification or short-circuiting in these systems is
rare (even where inlet/outlet placement is quite dysfunctional). For this reason simple inlet and outlet
structures are sufficient.
Consequently a single inlet and single outlet structure will be provided with suitable access points for
clearing blockages, sampling and with provision for water seals to prevent biogas escape. The inlet will
be at the north-west corner of the CAL where the DODA screen is located. The outlet will be near the
south eastern corner. The invert of the outlet structure will set the pond water depth at 5.0 metres.
3.6.3.Pond Seepage Control
-9
Managing Pond Seepage Control, a minimum permeability of 1 x 10 m/s will be provided on the CAL
floor and sides to minimise escape of effluent from the CAL. The preference is for a 1.5 mm HDPE liner
28
due to the high sodium content of the raw wastewater, which can be aggressive on a compacted clay
liner.
During installation of the liner, seam integrity testing will be required for every seam as welding is
completed to ensure that the seam meets quality specifications prior to installation. Subsequent damage
to the installed liner is unlikely since there is no mechanical action in the pond and the liner will be laid on
a suitably dressed sub-grade free of rocks or sharp objects that might penetrate the liner.
3.6.4.Freeboard
The CAL will maintain a freeboard of approximately 500 mm. This will be set by the outlet structure as
previously described. The large volume of the dam provides a significant safety factor. The 500 mm
freeboard allows 2 days design flow before overtopping occurs.
3.6.5.Bio-GAS Flare
The Bio-Gas Flare has been designed using the following process conditions;
•
Flow rate:
25 Sm3/hr normal, 50 Sm3/hr max.
•
Composition :
30%- 100% CH4
Balance CO2
H2O saturated
•
Pressure :
1 bar(a)
•
Temperature:
Ambient (25 C max.)
0
Swift have engaged Gasco Pty Limited’s to design fabrication and supply one (1) elevated flare for the
destruction of bio-gas as described above and shown in Figure 4. The flare will be fitted with a wind shield
to conceal the main flame body and to protect it from being blown out in strong wind. Ignition of main
flame is by way of continuous direct sparking at 1.5 second interval, powered by solar panel and a 12-volt
rechargeable gel cell pack which has capacity for continuous operation of 2 weeks in darkness. An in line
axial fan draws bio-gas from the covered pond and feed to the flare tip. The fan is also powered by a
solar power pack. A small flame arrester is fitted to prevent and arrest flashback and combustion along
the pipe work upstream. The flare is a stand-alone unit which is capable of operating for long periods
unattended, it has minimal control and does not require adjustment once commissioned. A set of
galvanized guyed-wires is used to stabilize the flare riser and wind shield. The proposed flare will convert
methane to water and carbon dioxide via combustion thus reducing the impact of greenhouse effect on
the environment. It will also destroy sulphur compounds, which are by-products in the anaerobic digestion
process; these are the chemicals responsible for the unpleasant smell in bio-gas. Destruction efficiency of
sulphur compounds and subsequent residual is affected by a combination of factors such as initial
concentration, ambient conditions and the treatment process. While it is not possible to accurately predict
29
destruction efficiency or to measure this with an elevated flare, Swift will review this once a detailed
analysis of the composition of bio-gas is available and that a target destruction level is established.
Swift have submitted detailed design information to the Civil Aviation Safety Authority (Advisory Circular
139-05 – June 2007) to have this project proposal application assessed. There is expected to be no
issues with the proposed Flare as it is well below exit velocity of 4.3m/s. Confirmation from CASA is
expect mid November 2010.
The proposed equipment specifications:
•
Flare Gas Flow Rate Sm3/hr:
50 max.
•
Turndown Ratio:
Infinite
•
Riser Height m :
4 (tbc)
•
Riser Size :
DN40, Sch 40
•
Riser Material :
CS, externally painted, Gasco standard
•
Wind Shield :
Stainless steel 316
900 X 1500 X 3 (dia.x h x d)
•
Ignition:
Continuous direct sparking at 1.5 sec interval
•
Power Source:
Solar Panel with 12-volt rechargeable gel cell pack
Note: All figures are nominal only at this time and subject to confirmation following completion of detailed
engineering.
Figure 4: Bio-GAS Flare Design
30
3.6.6.Commissioning
For commissioning, typically the CAL will be filled with water to permit the cover installation. Once the
cover and biogas train has been successfully installed, approximately 20m3 of sludge from the Currie STP
will be added to the CAL and wastewater feed from the DODA screen discharge initiated. Since the initial
CAL contents will be dilute and cool, it will take approximately 1 month for the CAL to approach normal
operating temperature and concentrations with a further month to stabilize to normal performance. During
this time, the CAL will receive constant daily inoculation of fresh anaerobic bacteria from the press
paunch liquor.
The progress of the pond can be followed by monitoring CAL outlet effluent temperature, redox (ORP),
pH, BOD5 and COD concentrations on a weekly basis. The long HRT of the pond suggests that a more
frequent monitoring is probably unhelpful. Simultaneously, the biogas volume produced gives an excellent
real time assessment of methanogenic activity.
31
3.7.
Operational Issues
3.7.1.Sludge Control
Anaerobic ponds achieve excellent COD removal for minimal sludge formation. It is expected that a
maximum of approximately 200 m3 of wet sludge (10% of pond volume) may accumulate annually at the
BOD loading used for the design. The remainder will be carried out in the effluent as TSS and destroyed
in the aerated pond. However, this sludge estimate is highly uncertain, and the amount may be quite less
given the reasonably long HRT.
Accumulation of sludge in the CAL is unwanted. Inspection / monitoring access points in the CAL cover
will allow adequate monitoring of any accumulation of sludge or crust in the CAL. Consequently, a settled
sludge removal system consisting of piping laid across the floor of the CAL will be installed at construction
to permit sludge withdrawal using a portable external pump or sludge truck for the task. Desludging
frequency of the CAL will be assessed depending on observations made at the time of the first desludging
(after 1 year).
3.7.2.Management of Crust Build-up under Cover
There is a risk that a crust or fat layer may accumulate over time under the cover. Insufficient experience
with this problem is available to assess the likelihood or rate of accumulation to be expected for this
installation. Where crust or fat accumulation is observed, a program of bacterial and enzyme dosing prior
to plant shutdown (typically 4 weeks in mid year) will be initiated to remedy the situation. Johns
Environmental successfully treated accumulation in a previous CAL by this method.
32
3.8.
Process Design – Aerated & Settling Ponds
This section describes the proposed aerated pond with the downstream settlement pond.
3.8.1.Reason for Selection
The effluent from the CAL contains sufficient biodegradable BOD concentrations (450 mg/l) that there is a
risk of local overloading in downstream facultative ponds unless sufficient aeration is provided, especially
under summer conditions when bacterial rates are highest. Consequently, the design proposes an
aerated pond to rapidly reduce biodegradable organic concentrations to low levels.
Aerated ponds are used successfully in the meat processing industry for this purpose, but one of their
major weaknesses is the large quantity of bacterial sludge generated, which tends to settle out in
downstream ponds. Desludging is expensive, especially where it is allowed to settle throughout large
ponds, and risks damage to the pond lining, which in turn can risk nutrient-rich effluent leaking into
groundwater over time. Consequently, the proposed design allows for a settlement pond immediately
downstream of the aerated pond in which the majority of the bacterial floc can settle and be removed
through purpose-built desludging pipes laid in the base of the settle pond. Short retention times are (< 3
days) are applied to this settlement pond to minimise algal growth or the development of anoxic zones.
The Settlement Pond design applied to the King Island upgrade is based on a design which successfully
settles sludge from the aerated RENOIR pond designed by Johns Environmental and operating
successfully in Western Australia on wastewater from a large beef processing facility since 2003 (See
Appendix F).
3.8.2.Mode of Action
A high concentration of aerobic bacterial flocs are grown and maintained in the Aerated Pond. The pond
is continuously aerated to permit reactions to occur which eliminate BOD from the water to the design
levels.
The mixed liquor is continuously discharged through a series of pipes into the settlement pond. The
discharge is designed to create even, gentle flow of floc-rich liquid into the quiescent environment of the
Settlement Pond, where the bacterial solids disengage from the treated effluent by settling. The clarified
effluent is then discharged into the downstream Polishing Ponds.
As required, the settled sludge can be pumped out of the Settlement Pond via the dual sludge pipes laid
at its base.
33
3.8.3.Process Design
Table 7 summarizes process design values for the two ponds. The aerated pond will be well mixed
through the action of two new 7.5 kW low speed surface aerators. These ensure that the anaerobic
effluent is rapidly mixed into the pond volume. The low speed aerators provide excellent oxygen transfer
rates to ensure that odour emissions are negligible.
The relatively long HRT for the aerated pond ensures good reduction in BOD5 levels even at the low
winter water temperatures (15 – 20oC). A first order kinetic design equation calibrated from a similar
aerated pond treating abattoir effluent suggests that the exit BOD5 concentration will be of the order of
150 mg/l at 15oC. However, in practice the pond will operate at warmer temperatures due to the residual
heat from the anaerobic pond and the exit BOD5 concentration should be of the order of 100 mg/l or less
in winter, and less again in summer.
Table 7: Design parameters for the aerated & settlement ponds.
Parameter
Number of Ponds
Design Flow
Design hydraulic retention
Volume @ TWL
Pond depth @ TWL
Design organic loading (OLR)
BOD loading
Operating MLSS
Design oxygen requirement
Design installed aeration
Supply as surface aerators
Design oxygen supply
Estd max wet sludge (5%TS)
Units
Aerated Pond
kL/day
days
kL
m
kgBOD/m3.d
kg BOD5/day
mg/l
kg O2/day
kW
kg O2/day
m3/yr
m
1
260
10.5
2,000
3.5
0.07
130
2 - 500
195
15
2 x 7.5 kW
Settlement
Pond
1
260
2.7
700
3.5
360
620
0.5
0.5
During summer, when temperatures are warmer, there is a possibility that some nitrification may occur,
resulting in a small reduction in total nitrogen.
The Settlement Pond is designed to provide very conservative overflow rates (< 1 m3/m2/day at half
depth) to ensure ample opportunity for settling of the bacterial floc and associated TSS from the aerated
pond. This is important, since the floc is typically very fine. It is expected that the TSS level exiting the
settlement pond will be 100 mg/l or less.
34
3.8.4.Odour Control
Negligible odour is expected from the aerated and settlement ponds. On occasion there may be an
“earthy” or “lake water” smell during aeration. The treated effluent is generally odour-free. Predictive
modally has been completed in accordance with EPA guideline and discussed further in section 3.12.
3.8.5.Bird Control
Net Pro Protective Canopies have been engaged to supply and install a bird exclusion canopy as shown
in Appendix B1, which will fully enclose all open WWTP ponds. The net selected is recommended for pest
and bird exclusion with the following specifications;
•
Colours:
Black Shade: Black 18% (± 2%)
•
Construction:
Raschel Warp Knitted U/V Block: TBA
•
Width:
17m Weight: 80g/m2 ± 5g/m2
•
Material:
HDPE Monofilament Selvedge: Reinforced
•
Burst Strength: TBA
•
Fire Rating:
N/A
•
Warranty:
10 Year Pro Rata U/V Stability 0.6% U/V Inhibitor (excluding colour fastness).
Figure 5: 17mm Heavy bird net
35
3.8.6.Groundwater Protection
The aerated pond will be constructed with a 2 mm HDPE liner to minimise seepage from the ponds into
the groundwater table. This ensures a hydraulic permeability of less than 1 x 10-9 m/s). A thinner 1.5 mm
HDPE liner will be used for the Anaerobic and Settlement Ponds.
3.8.7.Settled Sludge Management
The sludge removal pipe work in the base of the Settlement Pond will permit connection to a sludge pump
or truck for removal of settled sludge as required. Due to the long HRT in the aerated pond, and the fact
that the sludge remains in the base of the Settlement Pond for an extended period, it is probable that the
volume needing to be removed will be considerably less than the 620m3 indicated in Table 7. The sludge
will be suitable for land spreading or further digestion in a sludge drying pit.
3.8.8.Commissioning
3
The aerated pond will be commissioned with the addition of approx. 10m of sludge from the Currie STP.
The pond should approach design performance rapidly (within 1-2 weeks) since the growth rates of
aerobic bacterial populations is high.
Monitoring during commissioning will include measurements of temperature, dissolved oxygen, and pH
on a daily basis for the first 2 weeks, and weekly monitoring of BOD5 or COD and TSS concentrations
until the system settles down.
If the aerated pond struggles to accumulate sufficient bacterial concentrations, it is possible to return
sludge from the Settlement Pond back to the Aerated Pond to assist.
36
3.9.
Process Design – Polishing Ponds
This section describes the design and operation of the final two ponds in the proposed system.
3.9.1.Reason for Selection
The main roles of the polishing ponds are;
•
Reduce pathogenic bacterial numbers through natural attrition due to sunlight, high pH and
dissolved oxygen levels;
•
Reduce biodegradable BOD5 levels;
•
Allow for ammonia volatilisation during summer periods when the combination of high pH and
warm water temperatures combine to shift the equilibrium towards volatile ammonia in the water
column. Wind assists the mass transfer processes associated with ammonia loss.
•
Ensure good oxygenation of the effluent prior to release.
The polishing ponds provide robust and cost effective treatment and allow reuse of the water for
appropriate non-potable uses within the facility. Unfortunately the high nutrient levels remaining in the
effluent make it inadvisable for use in applications where bacterial or algae growth can cause difficulties.
3.9.2.Design Parameters
Table 8 outlines the main design features of the two polishing ponds. The design flows has been adjusted
to the 7-day average on the assumption that the hydraulic variation due to the 5-day processing cycle of
the abattoir has been damped out by the proceeding pond volumes of the CAL and aerated and settling
ponds. The polishing ponds have the following features:
•
A series configuration has been adopted to maximise bacterial die off, which is enhanced by plug
flow design (e.g. a number of ponds in series).
•
A final 5 kW low speed surface aerator is provided near the exit of Polishing Pond 2 to ensure the
final discharge to the 4 km pipeline conveying treated effluent to the ocean outfall is well
oxygenated. The action of this aerator should also break up any stratification in Pond 2 that can
be deleterious to disinfection performance.
•
The long axis of Pond 2 is arranged to allow good longitudinal wind run along its length from the
direction of the prevailing breezes.
•
Polishing Pond 1 is a small pond at the western end of the aerated and settlement ponds. It
primarily transfers effluent from the settlement pond to polishing pond 2.
37
Table 8: Design parameters for polishing ponds
Parameter
Units
Polish Pond 1
Polish Pond 2
kL/day
190
190
days
2.2
19
Volume @ TWL
kL
400
3,500
Pond depth @ TWL
m
2.0
2.0
Design organic loading (OLR)
kgBOD/ha.d
475
80
BOD loading
kg BOD5/day
19
19
Design Flow
Design hydraulic retention
Design installed aeration
kW
5
Supply as surface aerators
-
1 x 5 kW
m
0.5
0.5
The organic BOD5 loadings displayed in Table 8 assume an entry BOD5 concentration of 100 mg/l from
the discharge of the Settlement Pond. Although the “design organic loading” for Polishing Pond 1 is very
high at 475 kg/ha.d, in reality, the concentration is sufficiently low that odour is very unlikely. The BOD
load is only of the order of 20 kg/day. For Polishing Pond 2, the loading will typical be 80 kg/ha.day.
3.10. Overall Pollutant Removal
Table 9 outlines the design percentage removals of important pollutants across the total pond system.
Table 9: Design pollutant removals across the pond system
Parameter
BOD5
TSS
Oil & Grease
Total Nitrogen
Total Phosphorus
Thermotolerant coliforms
% removal
Summer
Winter
99.3
98.7
95
95
96
96
38
10
10
10
99.9
99.9
38
3.11. Solid Waste Management
The management of the discharge of pollutants from point sources, such as wastewater treatment plants,
will be managed in accordance with the following hierarchy of waste management:
1. Waste avoidance;
2. Reclamation and recycling;
3. Waste reuse;
4. Waste treatment to reduce potentially degrading impacts; and
5. Waste disposal.
Swift have implemented waste avoidance practices within production areas, to ensure that all reasonable
actions have been taken to reduce the volume of wastewater and pollution loads being discharged from
the abattoir and rendering activities, and that trade waste controls are in place to ensure that the effluent
does not contain contaminants that cause environmental harm.
Solid Waste Management will remain consistent with current practices and the site will continue to
manage its waste generation in accordance with the EMPCA (Controlled Waste Tracking) Regulation.
The Regulated Waste is generated on site is detailed in Table 10. These are removed by an EPA licence
operator located on King Island.
Table 10: Solid Waste Description
Solid Waste Description
•
Paunch
EPA Description
•
material
•
DODA
WWTP Sludge
K100
poultry and fish processing waste)
•
Screenings
•
Animal Effluent and Residues (abattoir effluent,
EPA Class
K100
•
K100
Our expected de-sludging program is based on like experience with systems around Australia. For
example, the expected frequency for desludging anaerobic lagoons is 20 years, Aerobic (10 years) and
Setting ponds (every 1-3 years).
The WWTP polishing pond 1 is not expected to require desludging annually with the 2nd and final
polishing pond every 5 years. This program will be reviewed annually after commissioning.
39
Swift has made positive steps in waste reduction by incorporating within the abattoir operations the
means to recover by-products for the rendering plant, recovering blood, separating paunch material to
return to the land, and removing screenings and biosolids matter from the wastewater for alternative use.
The recovery, reuse and recycling of effluent and biosolids is encouraged and supported to allow positive
and sustainable environmental outcomes. The DTAE Guidelines state that “The discharge of effluent to
surface waters should not be permitted unless it is demonstrated to the satisfaction of the regulatory
authority that effluent application to land is not feasible or would result in a higher net environmental risk”.
Improved effluent quality and careful consideration of discharge arrangements from an environmental
perspective are key requirements of the State Policy.
3.12. Air Emissions (Odour Dispersion Assessment)
Swift commissioned EML (Air) Pty Ltd to complete an odour dispersion modelling and impact assessment
of the expected odour emissions from the proposed WWTP and existing equipment at the abattoir. This
dispersion modelling has been carried out in accordance with Environmental Protection Policy (Air
Quality) 2004 and the Atmospheric Dispersion Modelling Requirements Draft V0.91 October 2009. The
full details of this report can be seen on Appendix L – Odour Dispersion Assessment, Report No 86330.
The model predicted dispersed odour ground level concentrations for the existing biofilter and proposed
WWTP to extend beyond the boundary of the premises. However, the predicted 2 OU contour 99.5th
percentile 1-hour average complies with the odour criteria specified by the Environment Protection Policy
(Air Quality) – Schedule 3.
EML (Air) Pty Ltd has determined that based on their Odour Dispersion Assessment, the predictions of
adverse impacts attributed to odour from the existing biofilter or the proposed WWTP on the beneficial
uses of air environment beyond the boundary are unlikely to occur.
It is important to note, that the Abattoir plant has recently undergone a full upgrade that has resulted in
improvement operating efficiencies and delivered significant environmental improvement to odour
reductions. These inclued improved Steam recovery, enclosing wastewater transfer stations and paunch
storage and refurbished biofilter.
40
3.13. Energy Management
The proposed WWTP will require the following estimated energy sources to facilitate the effective and
sustainable operation of the facility. The following Table 11; shows the energy using apparatus required.
All equipment will be managed through an online monitoring system (SCADA) that will enable variable
speed (on / off) setting to be managed automatically. The aerator will be controlled by this method via
Dissolved Oxygen (DO) level monitoring, saving energy through decrease aerator operation.
Table 11: Energy Using Apparatus
Apparatus
Primary Pit 1 Effluent transfer pump no 1 - Duty
Primary Pit 1 Effluent transfer pump no 2 Standby
kW (existing)
kW (new)
11
11
DODA Effluent solids screen
1.8
Setting Pond Surface Aerator No 1
7.5
Setting Pond Surface Aerator No 2
7.5
Polishing Pond Final Surface Aerator No 1
5
Effluent Transfer Pump No 1 – Duty
11
Effluent Transfer Pump No 2 – Standby
11
Biogas Flare Blower
3
Air Compressor
3
General Light and Power (accessories)
Total
0.5
22
50.3
The switchboard will be designed so if biogas is determined sufficient to run a small 50kW generator,
automatic swing over to generator power from mains can be initiated from the biogas pressure and flow
meters.
3.14. Noise Management
The proposed WWTP will produce ambient background noise less than 35dBA that would impact any
residential development in the area. Noise sources are limited to the aerators, flare, pump operations and
general operational works (DODA screen / solids collection). A predictive Noise Impact Assessment has
been completed by Acoustics RB Pty Ltd (Appendix N).
3.15. Traffic
There is expected to be little requirement for vehicle movement in to the plant. The majority of traffic
movement will be isolated to the WWTP construction zone with excavator, dozer and tip trucks.
41
After commissioning, the only traffic requirements will be by tractor and trailer to remove the solids
generate via the DODA screen (1 load per day, 5 days per week) between the hours of 7am to 3 pm as
per current practices.
3.16. Construction and Commissioning
3.16.1. Construction Phase
The targeted construction plan (as shown in Appendix C1-4) is a guide only and subject to change
pending date of EPA approval of this DPEMP, King Island council approval, community review feedback,
contractor availability / timelines and unseasonal weather conditions. The construction works will consist
of the follow;
•
Plant stormwater segregation (currently underway with plan upgrade improvements)
o
Stormwater will be redirected away from the effluent system where identified –namely
redirecting entrance roadway stormwater, redirecting roof stormwater from existing areas.
o
Improved stormwater collection from the factory roof including the new blast freezers will
be redirected into the on site stormwater tank for reuse as cattle yard wash down water
•
Site excavation (Clay harvesting)
o
Clay harvesting will be done during the construction of all the ponds and placed to one
side. This will be used as a base prior to the installation of the synthetic HDPE liners to
obtain a solid, smooth surface free of abrasive materials.
•
Anaerobic and Facultative Pond construction
o
Construction will include compaction testing, and preparation of each pond surface to
accommodate synthetic HDPE liners to achieve requirements as specified and requested
by EPA Tasmania
•
Anaerobic Cover Installation
o
The CAL cover will be designed and installed for capture of methane gas emissions and
vented to a flare or potential future energy recovery. It is hoped the energy recovery will
be sufficient in time to self power the effluent treatment system if this option is viable.
•
Bird Netting Installation
o
The uncovered ponds will have a bird netting structure erected over the ponds to prevent
birds utilising the waters and thus creating bird strike issues for the incoming air traffic at
the airport (roof height to 4mt above TOW, 4mt posts on the central wall for internal
support with 2 access points either end of central dam wall – refer diagram Appendix B1)
•
Flare Installation
o
•
The flare installation by Gasco as per section 3.6.5.
Pump station pit and pipelines
o
A pump station pit with automatic level control will control the final polishing pond levels.
At the end of the stage 1 works this will transfer back to the current Porky creek
discharge point, albeit at significantly improved quality – once stage 2 works are
approved then it will pump to the ocean outfall
42
•
Hard stand for DODA screen and solids removal
o
This is to provide good access to turn the solids removal tractor and trailer
o
The DODA screen is proposed to be erected on a frame sufficiently high such that gravity
discharge of solids can be achieved to a tractor and trailer setup – these solids will be
added to the paunch grass collected elsewhere on site
•
Roadway construction
•
Installation of temporary outfall line to Porky creek.
3.16.2. Project Timetable
The expected construction period, subject to the approval of the DPEMP and construction phase being
completed within the proposed timelines, is shown in Appendix C1-4.
43
4.
The Existing Environment
4.1.
Planning Aspects
4.1.1.Location Selected
As shown in Section 3.1.1, the proposed WWTP location has been subject to previous like proposal
presented to the EPA by previous proprietors whom operated the site abattoir. The proposed site is
owned and operated by Swift Australia Pty Limited and formally contained in the existing site Certificate of
Title, Volume 47288, Folio 1, show in Appendix E.
The site is subject to the provisions of the King Island council planning scheme, which requires Swift to
file the required Development Application and supporting information (Statement of Environmental
Effects). The specific landholding has been part of the King Island Abattoir since the early 1950’s. The
land surrounding the site to the south and west is used for primary production, predominately grazing on
land classified as being within the Rural Agriculture zone. The land to the North and East is occupied by
King Island Airport.
4.2.
Environment Aspects
The proposed WWTP site located on Morrison Avenue, 7km north of the Currie Township, will provide the
following environmental, public health, social and economic benefits:
•
Protects public health;
•
Protects Porky Creek / coastal ecosystem;
•
Protects surface waters and groundwater;
•
Improves local amenity
4.2.1.Topography
The area is characterised a flat. The site slopes slightly from the north east corner (elevation 45 m) about
2 m to the western and southern boundaries.
4.2.2.Geology (Soils)
ADG Laboratories have been commissioned to analyse the soil sample collected from 3 test points
located on the proposed site for the WWTP as shown in Appendix A2. Test pit, located in the anaerobic
pond was dug to a depth of 7 metres, with test pits 2& 3 located in the aerated and settling pond area
terminated a 3.1 metres. The soil profile reports are shown in Appendix M and the typically characteristics
can be summarised as being an initial layer of silty / sand, followed by a layer of sandy silty clay, then
clayed sand and finally sandy gravel.
44
4.2.3.Ground Water
No ground water monitoring bores are being proposed for the new WWTP site. The WWTP is expected to
have no adverse impacted groundwater geology due to the installation of 1.5 & 2mm synthetic HDPE
liners in all ponds as detailed in section 3.6.3 & 3.8.5.
Test Pits were constructed on the 17th July 2010, with test pit 1 allowing observations to a depth of 7.0m.
The results of the soil structure and condition seen on the day are detailed in Appendix M. This
determined that there was no groundwater leaching into any of the test pits.
The pond will utilised the recovered soil (including clay) in the preparation of a smooth compacted pond
surface prior to the installation of the fully sealed synthetic HDPE liners protecting the area from any lose
of wastewater to groundwater.
4.2.4. Flora and Fauna
The proposed location for the WWTP will not disturb any established plantations. The area is currently a
mix of pasture grasses that is consistently grazed by cattle. A survey of the area was completed using
Natural Values Atlas report number 40096 completed 02:29:46 PM Thursday, 9th August 2010 which
reviewed the following parameters.
•
Threatened Flora:
buffers 500m and 5000m
•
Threatened Fauna:
•
Conservation Significance Flora:
•
Conservation Significance Fauna:
•
Weeds:
•
Tasmania Vegetation:
buffer 1000m
•
Threatened N on-Forest :
buffer 1000m
•
Geo-conservation:
buffer 1000m
•
Tasmanian Reserve Estate:
buffer 1000m
The report determined that there are no threatened plant species found in the surveyed areas. The final
report is combined wit the Dam Assessment Report – Application sent to the Assessment Committee for
Dam Construction, Water Licence and Dam Administration of the Water Management Branch, Water
Resources Division, Department of Primary Industries, Parks, Water and Environment Ground in Hobart.
A 30 m border of medium height native vegetation is located along the southern boundary of the site.
45
4.2.5.Climate
Climatic information needed to estimate treatment process operating temperatures, rainfall and other
relevant data was sourced from Bureau of Meteorology for the King Island Airport Station 098017. The
data covers 36 years of data for rainfall (1974 – 2010) and 14 years for temperatures (1995 – 2009). It is
summarised in Appendix 2.
The climate is temperate with half the mean rainfall falling in the 4 months June – September, typically as
light rain (< 10 mm/day). Some rain occurs during other months, but summer is typically dry. Annual
mean rainfall is 854.8 mm.
Evaporation data are not measured on King Island, but the Bureau of Meteorology calculates daily
evapotranspiration rates. During 2009, which was a 90 percentile wet year, evapotranspiration amounted
to 1,023 mm. There is relatively little difference between annual evaporation and rainfall.
Mean maximum air temperatures are 21oC and 13oC in mid-summer and mid-winter, respectively.
King Island is exposed to Bass Strait winds and wind roses show a frequently strong wind pattern even in
the mornings. This is optimal for polishing pond aeration. In the afternoon, the prevailing winds are
predominantly from the western quadrant, but with easterly contributions during spring and summer. The
westerly winds blow across the proposed pond site towards the facility and the adjacent airport. In the
mornings, prevailing wind patterns are more confused with contributions from all directions, depending on
season.
The following climate data has been sourced from the Bureau of Meteorology King Island Airport weather
station.
Climate Data - King Island 1995 to 2010
25
140
120
20
15
80
60
10
Rainfall (mm)
Temperature ( oC)
100
40
5
20
0
0
January
February
March
April
May
June
July
August
September
October
November
December
Month
Mean rainfall (mm) for years 1974 to 2010
Mean maximum temperature (Degrees C) for years 1995 to 2010
Mean minimum temperature (Degrees C) for years 1995 to 2010
46
4.2.6.Natural Events
Fire - The area surrounding the site is predominately grazing land, typically lined at the boundaries by tea
trees. This does not eliminate the risk of fire, however reduces the possibility of severe bushfire affecting
the site and immediate surrounds.
Flooding - The site is located on an elevated nature rise which will significantly reduce the risk of any
natural flood event to impact the proposed site of the Wastewater Treatment Plant.
4.2.7.Heritage - Areas of Special Conservation
The area identified has been heavily disturbed over many years of clearing, farming and grazing
activities. An archaeological survey for Aboriginal Heritage was conducted on the 4th Augusts 2010 (refer
Appendix H) by Mr Vernon Graham (Senior Aboriginal Heritage Officer & Principal of Palawa Heritage
Services Pty Ltd).
At the time, no Aboriginal artefacts were located during the survey. In relation to European Heritage, the
archaeological report noted there were three areas in the local area that were referred to in early historic
accounts of King Island:
•
The campsite at the mouth of the Fraser River where a group of naturalists from the French
scientific expedition led by Baudin stayed for 13 days in 1802;
•
An early sealers’ campsite near Cower Point which is referred to by the French naturalists in
1802; and
•
A nineteenth century snarer’s camp in the Eldorado Creek vicinity where the Field Naturalist’s
Club of Victoria camped during their 1887 trip to King Island
Swift will also ensure that, if at any time during works, workers suspect Aboriginal or European heritage,
works will cease immediately and AHT or Heritage Tasmania will be contacted, as appropriate, for advice.
4.3.
Socio-Economic Aspects
The Swift plant is the largest employer on the island outside the Council, employing approximately 85
people directly and indirectly supports around 90 farming families.
The major industries on King Island include the Cray Fishing industry, where there are about 15 local
fishermen who run boats around both Tasmania and King Island. The majority of their catch goes direct to
China and Japan. National Foods operates the King Island Dairy and produces world famous cheese,
cream and yoghurt. They employ approx 80 people and are along with the Abattoir the biggest employer’s
on the island. There is also a Kelp factory processes bull kelp and they ship their product to a Sister
company in Scotland. The factory employs approx 20 people.
47
4.4.
Alternative sites
No other alternative site has been seriously considered by Swift. The current location selected has been
subject to previous proprietor, EPA and Council encouragement and recommendations for the past 5
years.
48
5.
Potential Effects and Their Management
5.1.
Air Emissions (Odour Dispersion)
As previously outlined throughout sections 3.6.1, 3.8.4 and 3.12 the new WWTP will result in an overall
improvement to the impact of the site operations that contribute to odour by decommissioning the DAF
and covering the Paunch tanks. The potential effects of odour from the proposed WWTP and the
mitigation measure that will be employed to eliminate or reduce these are detailed in Section 5.1.1, table
12.
5.1.1.Potential Effects - WWTP Emissions
The provision of a synthetic cover across the top water surface of the CAL will ensure that the majority of
odorous emissions associated with WWTP are captured and combusted via a biogas flare. Odour
emissions from the aerated and settling ponds can be expected to be negligible as detailed in Section
3.12. The follow table 12 addresses all potential air emission points;
Table 12 New Wastewater Treatment Plant Potential Odour Sources
Potential odour Source
Paunch Tank
Fan Press
Assessment
Mitigation
Medium source of odour emission
•
Building secondary containment bund
during hours of operation
•
Installation of cover
Low source of odour emission during
•
Maintenance of Fan press in good
hours of operation
Abattoir Wastewater
Closed system – sealed lid / removal
transfer pit
for servicing only
DODA Screen
Low source of odour emission during
working order
•
N/A
•
Maintenance of DODA screen in good
hours of operation (2 hrs / day)
Solids Collection
Very low source of odour emission
working order
•
Waste to be collected within 24 hour for
land application
Covered Anaerobic Lagoon
Fully seal cover
•
Potential source of odour emission in
•
Biogas to be burnt via Flare
(CAL)
Biogas Flare
event of flame failure
continuous direct sparking at 1.5 second
interval, powered by solar panel and a
12-volt rechargeable gel cell pack which
has capacity for continuous operation of
2 weeks in darkness
st
1 Aerated Pond
Low source of odour emission
•
Anaerobic waste reduction analysis
monitoring
•
aerator will operate only as required
(DO level controller)
Settling Pond
No odour emissions expected
•
DO level monitoring
Sludge Removal
Low odour emission expected
•
Very low frequency of activity (1 – 3
49
years)
st
1 Polishing Pond
nd
2
Polishing Pond
Final Aerator
•
DO level monitoring
•
DO level monitoring
•
aerator will operate only as required
(DO level controller)
Porky Creek Outfall
5.2.
•
DO level monitoring
Wastewater
The final effluent quality is presented in Table 4. The pond system design seeks to provide a final effluent
pollutant removal as detailed in section 3.10; that is expected to be Odour-free after treatment and during
storage in the final polishing dam; and permits discharge to Porky’s Creek with no visible scums, slicks or
colour.
5.2.1.Mitigation Measures
The WWTP will have the facility to return wastewater to the initial anaerobic section via the DODA screen
in the event that outfall parameters are not achieved. Further operation mitigation measures are detailed
in Section 3.7.
5.3.
Ground Water
The site sources 100% of its water requirements from ground water bored located approximately 4 km
directly north of the site. There is no ground water extraction bores located on the abattoir title.
The groundwater system is not expected to be impacted as a result of the construction, commissioning
and ongoing operation of the proposed WWTP. There has been no evidence of shallow groundwater
being detected in test pits 1 – 3 (Appendix M) on the proposed site. Wastewater will be metered exiting
the proposed WWTP.
5.4.
Noise Emissions
The ambient background noise is not expected to be noticeable off site. The aerators are the only
equipment that has the potential to generate low level noise. No further sound proofing is deemed
necessary due to the location and distance from local residence.
Noise impacts have been considered and Swift has selected very efficient, stable (dynamically and
statically) aerators that will result in low surface noise. The specification for the 2 x 7.5 kWh and 1 x 5.5
kWh aerators are shown in Appendix G & H respectively.
50
5.5.
Solid and Controlled Waste Management
During construction the project, is not expected to produce Solid or Controlled waste with all material
being used on site for the pond construction. In the event of waste being generated during construction,
commissioning this material will be managed in accordance with existing site management procedures
and disposed of using approved waste transporters. The waste management hierarchy will be adopted
where ever practicable to minimise waste generation and recycle if appropriate.
The new WWTP will generate Solid waste from the DODA screen and future Sludge from pond cleaning
that will be managed in accordance with EPA guidelines as detailed in section 3.11.
5.6.
Dangerous Goods
The construction of the proposed facility will involve the use of some combustible materials, such as fuels
for construction equipment. These materials will be used, stored and transported in accordance with the
Dangerous Substances (Safe Handling) Act 2005. After commissioning, there will be no dangerous goods
required to be stored or handle in and around the proposed WWTP other than that required for the
maintenance of pumps and aerators.
Any dangerous goods (consumables) used on site will be stored in accordance with Australian Standards
and legislative requirements.
5.7.
Greenhouse Gases and Ozone Depleting Substances
Greenhouse Gas (GHG) emissions from the proposed WWTP construction will be isolated to the
construction machinery and any associated transport to and from the site. Swift will ensure that all
contracted equipment used on site shall be maintained in good working order.
During the operation of the proposed WWTP facility, biogas flow generation is estimated to have a
potential peak biogas flow is 50m3/hour. The Biogas composition is also estimated to contain
2
approximately 70 - 75% methane, with the remainder mainly being CO . A methane analyser, biogas
mass flow meter (as shown in Appendix J) and PLC are proposed to be installed to monitor this system.
-e
CO2 emissions from the proposed new CAL are with 80% COD removal and no capture 1,767 tonne
CO2-e / year or as intended in this project, all biogas captured and flared 23 tonne CO2-e / year. This is a
98.7% reduction in emissions which potential further savings if the biogas is used to displace fuel for
electricity generation.
51
5.8.
Visual Effects
The overall visual effects will not be visible from the public road servicing the Airport due to the lining of
tree surround this area. However, the size and shape of the proposed WWTP can be seen on the site
plans shown in Appendix A1. The final ponds will also be covered by bird netting as shown in Appendix
B1.
The maximum height of any structure is expected to be 4m. The site is part of the Abattoir operations and
is expected to complement the recent upgrade to this site.
5.9.
Hazard Analysis and Risk Assessment
A preliminary risk assessment has been undertaken for this project in the form of the Dam Assessment
Report (see Section 4.2.4). There has been no significant risks identified with serious consequence,
however the application of mitigation measures using the hierarchy of control (eliminate, substitute,
engineering, administration and protection) has served to minimise the risk of each. This will be reviewed
and reflected in the site Environmental Management Plan.
5.10. Fire Risk
A fire management plan will be developed prior to the operation of the WWTP. The plan will outline any
fuel reduction measures needed to be undertaken of the surrounding area and ongoing maintenance.
The construction of the proposed facility will involve the use of some combustible materials, such as fuels
for construction equipment. These materials will be used, stored and transported in accordance with the
Dangerous Substances (Safe Handling) Act 2005.
All management measures relating to prevention and response to fire at the proposed facility will be
incorporated into an Emergency Response Plan, which will be developed prior to commissioning. All
electrical infrastructures will be constructed in compliance with the Tasmanian Electricity Code to
minimise risk of electrical faults that may act as ignition sources.
5.11. Infrastructure and Off-site Ancillary Facility
The construction phase will require the initial delivery of materials and construction equipment, however
minimal. The ongoing management of the proposed WWTP will have no additional impact on local
infrastructure.
5.12. Environmental Management System
Swift will ensure that ensure that the site management team will induct all contractors, ensuring all
appropriate environmental management expectations are communicated prior to commencing work.
52
6.
Monitoring and Review
Swift will initiate an intensive monitoring program that will be subject to future Environment Protection
Notice issued by EPA. Monitoring of the wastewater discharge will be undertaken to:
•
•
•
Validate improved wastewater discharge characteristic;
Optimise WWTP performance; and
Assess compliance with targeted emission limited outlined with this DPEMP.
It is anticipated that after the initial commission period (the above measures achieved) and prior to the
establishment of the Ocean Outfall, it is the intention that the monitoring frequency will be reduced to bimonthly or quarterly.
6.1.
Wastewater Discharge Monitoring
Monitoring points will be established to validate the performance of the WWTP. These points will include
the following:
•
Wastewater supply inlet to CAL (after DODA screen);
•
Inlet to Facultative Lagoon; and
•
Facultative Lagoon Outlet.
All samples will the collected by Swift and sent via airmail to EML (Chem) Pty Ltd. Samples shall be
collected and analysed in accordance with the relevant Australian Standards at NATA certified laboratory.
EML (Chem) Pty Ltd, located in Melbourne, Victoria will provide this service and sampling jars, labels and
sample holding times, storage and transportation will be consistent with establish procedures and
practices on site.
Additional observations will be recorded at the time of sampling to assist with the review of any unusual
results. These observations shall include the following areas:
•
Date and time of sample
•
Name of sampler
•
Sample location
•
Ambient weather conditions (unusual events, cloud cover, wind, odour, visible variations)
•
General comments
The wastewater parameters included in the monitoring program will include the following table 13.
53
Table 13 - Wastewater Monitoring
Parameter
Unit
-
pH
Conductivity
Sample frequency
Sample type
CAL Inlet
Inlet Facultative
Outlet
Monthly
Monthly
Monthly
Grab
Monthly
Monthly
Monthly
Grab
BOD
mg/l
Monthly
Monthly
Monthly
Grab
COD
mg/l
Monthly
Monthly
Monthly
Grab
Monthly
Monthly
Monthly
Grab
Faecal coliforms
Non filterable residue
mg/l
Monthly
Monthly
Monthly
Grab
Suspended Solids
mg/l
Monthly
Monthly
Monthly
Grab
Total Dissolved Solids
mg/l
Monthly
Monthly
Monthly
Grab
Total phosphorous
mg/l
Monthly
Monthly
Monthly
Grab
Orthophosphate
mg/l
Monthly
Monthly
Monthly
Grab
Total kjedahl nitrogen
mg/l
Monthly
Monthly
Monthly
Grab
Ammonia – nitrogen
mg/l
Monthly
Monthly
Monthly
Grab
Nitrate – nitrogen
mg/l
Monthly
Monthly
Monthly
Grab
Nitrite – nitrogen
mg/l
Monthly
Monthly
Monthly
Grab
Calcium
Magnesium
mg/l
Monthly
Monthly
Monthly
Grab
mg/l
Monthly
Monthly
Monthly
Grab
Sodium
mg/l
Monthly
Monthly
Monthly
Grab
Potassium
mg/l
Monthly
Monthly
Monthly
Grab
Chloride
mg/l
Monthly
Monthly
Monthly
Grab
Sulphate
mg/l
Monthly
Monthly
Monthly
Grab
Oil and Grease
mg/l
Monthly
Monthly
Monthly
Grab
6.2.
Odour Monitoring
Odour dispersion will be monitored and recorded daily during the commissioning program. Predictive
modelling has been completed in preparation of this DPEMP as shown in attached appendices; this will
be repeated within 12 month of commissioning the WWTP and every 3 years thereafter.
6.3.
Reporting Requirements
Swift currently maintains a complaints register and incident reporting system to record any event and
corrective actions taken to assess and rectify all issues as appropriate. Any incidents that have the
potential to create environmental harm or nuisance will be reported as required by the current site EPN.
54
7.
Commitments
Swift is committed to undertaking the construction and operation of the proposed WWTP as described in
the DPEMP. These are shown in the following table.
Table 14 Commitments
Number
1
2
Details
Swift commit to the development of an Environmental
Management Plan (EMP) prior to commissioning
Swift commit to the development of an Emergency Response
Plan prior to commissioning
DPEMP
Reference
Responsibility
5.9
Swift
5.10
Swift
6.2
Swift
Swift commit to undertake a review of odour 12 months after
3
commissioning of the Wastewater Treatment Plant (and at
three-yearly intervals thereafter)
4
5
6
7
8
CAL emissions will be captured and flared continuous
Swift
A CAL monitoring program will be established to monitoring and
Swift
control unwanted crust formation
A program will be established to manage the Aerator operation
Swift
to provide adequate control in the ponds
A monitoring program will be established for the inspection and
Swift
maintenance of the bird netting
Swift commit to maintenance of complaints and incidents
register
6.3
Swift
55
8.
Conclusion
The proposed WWTP presented by Swift Australia, will ensure that significant improvement will be
achieved to the wastewater discharge loading and has been designed to treat an average flow of
260KL/day, 5 days / week.
The proposed treatment system consists of:
•
Retaining the existing DODA rotary screen and fan screw press (treating the paunch stream);
•
Retiring the existing DAF;
•
Constructing a new 2.3 ML nominal covered anaerobic lagoon (CAL) with associated biogas
handling;
•
Constructing a new 2 ML aerated pond equipped with low speed surface aeration to further
destroy organic material and an associated 0.7 ML settling zone to actively manage carryover
suspended sludge from the aerated pond;
•
Constructing two new polishing ponds – the first of 0.4 ML volume, the second of 3.5 ML volume
to polish the effluent. The last pond will include a small surface aerator near the discharge to
maximise dissolved oxygen levels prior to discharge to the outfall transfer pipe.
The proposed WWTP will:
•
Improve wastewater quality;
•
Reduce nutrient load to Porky creek;
•
Reduce solid waste generation;
•
Reduce Greenhouse Gas emissions;
•
Reduce and Control odour;
•
Improve wastewater impact on groundwater ;
•
Produce effluent which has high potential for future reuse;
•
Have no impact on Aboriginal cultural heritage;
•
Little to no impact on flora and fauna on the site identified.
This document addresses various design and operational issues with a focus on ensuring that the system
is robust and reliable. The project will have a net positive environmental impact, ranging from
improvements to local odour conditions; reduce GHG emissions and the minimisation of traditional waste.
The project represents the long term viability solution for the King Island Abattoir site, positioning it as a
leading edge WWTP with future possibility of renewable energy production.
56
9.
Abbreviations
ADWF = average dry weather flow
AHDF = average high day flow (tannery only)
AOTR = actual oxygen transfer rate.
Bio-P = Biological Phosphorus removal
BNR = Biological Nutrient Removal
BOD5 = Biochemical Oxygen Demand (measured in 5 days at 20°C) (mg/l).
CAPEX = Capital Cost
COD = Chemical Oxygen Demand (mg/l)
DAF = Dissolved Air Flotation
DPEMP = Development Proposal and Environmental Management Plan
DO = dissolved oxygen concentration (mg/l)
EP = Equivalent Person (used as basis for sizing sewage plants)
E.coli = Escherichia coli (cfu/100ml)
F/M = Food/Micro ratio – a measure of organic loading to activated sludge plants
HRT = hydraulic retention time (days)
LTR = Low Temperature Rendering Plant
NFR = Non-Filterable Residue, similar to SS.concentration (mg/l)
MLSS = Mixed Liquor Suspended Solids (mg/l)
MLVSS = Mixed Liquor Volatile Suspended Solids (mg/l)
ND = Not Determined
NH3-N = ammonia-nitrogen concentration (mg/l)
NO2-N = nitrite-nitrogen concentration (mg/l)
NO3-N = nitrate-nitrogen concentration (mg/l)
O&G = Oil and Grease
PF = Peaking factor
SBR = Sequencing Batch Reactor
SCOD = Soluble Chemical Oxygen Demand (mg/l)
Sol BOD5 = soluble Biochemical Oxygen Demand (mg/l)
SRT = solids retention time (sludge age) (days)
SS = suspended solids concentration (mg/l)
STP = Standard Temperature and Pressure
SVI = Sludge Volume Index (ml/g)
TCOD = Total Chemical Oxygen Demand (mg/l)
TDS = Total Dissolved Solids (mg/l)
TKN = Total Kjeldahl nitrogen (mg/l)
TN = Total Nitrogen concentration (mg/l)
57
TP = Total Phosphorus concentration (mg/l)
TSS = Total Suspended Solids (mg/l)
TWL = top water level
UV = UltraViolet
VFA = Volatile Fatty Acids
VOC = Volatile Organic Compound
VS = Volatile Solids
VSS = Volatile Suspended Solids
WADF = Week-averaged daily flow (tannery only)
WAS = Waste Activated Sludge
LIST of UNITS
kg/ha.d = loading rate in kilograms per hectare per day
kg/m2.d = loading rate in kilograms per square metre per day
kL/d = kilolitres (cubic metres) per day
mg/L = milligrams per litre = ppm.
m/h = metres per hour
m3/m2.d = surface loading rate in cubic metres per square metre per day
ML = Megalitres (1,000 kL)
58
10. References
1
2
3
4
1
DPIWE (2001). Emission limit guidelines for sewage treatment plants that discharge pollutants
into fresh and marine waters. Hobart. June 2001.
x
2
AQIS (2008) Efficient use of water in export meat establishments. Meat Notice 2008/06. Issued
13 October 2008, Canberra.
X
3
MLA (2007). Environmental best practice guidelines for the red meat processing industry. Eds.
M Johns, S McGlashan, & A Rowlands. Published Apr 2007, MLA, North Sydney, NSW.
x
4
MLA (2009). Anaerobic pond cover vulnerability – assessment of available cover materials.
Project A.ENV.0072 Report prepared by Golder Assoc., Perth. Published Aug 2009, MLA, North
Sydney, NSW.
5
Johns Environmental Pty Ltd, “Process Design for Wastewater Treatment Upgrade at King Island
Meat Processing Plant” (September 2010)
6
EML Air Pty Ltd, Odour Dispersion Assessment – Report No 86330 (September 2010)
59
Appendix A1 - Design Drawing
60
61
62
Swift
T +61 3 93164732
Appendix B1 - Design Drawing
[email protected]
www.jbsswift.com.au
Appendix B2 - Design Drawing
64
Appendix C1 – Project Plan
65
66
67
68
Appendix D – DPEMP project specific guidelines
Swift
T +61 3 93164732
[email protected]
www.jbsswift.com.au
70
71
72
73
Appendix E – Certificate of Title
74
75
76
Appendix F - RENOIR Settling Data
The Settlement pond design is based on the successful settling zone in the Johns Environmental RENOIR
technology. In the settle zone, the effluent enters in a hydraulically controlled manner to minimise fluid
disturbance. The sludge settles and can be withdrawn in a similar manner to the system proposed for
the CAL – namely a sludge piping system attached to a sludge pump. The treated, clarified effluent
overflows the settle zone with much reduced TSS levels.
Since the settling zone is less rigorously constructed compared to the very expensive purpose-built
secondary clarifiers servicing modern activated sludge plants, a very conservative overflow rate is used.
The success of this strategy in the RENOIR is seen in the figure below. Whereas mixed liquor TSS
concentrations in the RENOIR aerated basin were as high as 2,500 mg/l or more, TSS in the pond
effluent remained below 100 mg/l. Only at extreme TSS levels in the aerated basin (> 2,500 mg/l) were
higher effluent TSS observed.
The facility where the RENOIR was installed processed on average 1.5 ML/day effluent.
Effectiveness of RENOIR settle zone – 9 months data.
77
Appendix G - 7.5 kWh Aerator Specifications
78
79
80
Appendix H – 5.5kWh Aerator Specifications
81
82
83
Appendix I – Heritage Report
Palawa Heritage Services Pty Ltd- Aboriginal Archaeology
ACN 112 128 015 - ABN 97 112 128 015
Aboriginal Cultural Heritage Survey
Aboriginal Heritage Consultant
Cross Cultural Awareness Training, Arts Traditional Crafts & Photography
Vernon Graham
Aboriginal Heritage Consultancy &
Photographer
61 Galvin Street
South Launceston
Tasmania 7249
Phone 03 63 431 036
Mobile 0417 378031or 0408 035884
22nd August, 2010
Troy White
Group Environment Manager
Swift Australia Pty Limited
30 Industry Park Drive, Brooklyn VIC 3012
PO Box 36, Altona North VIC 3025
E: [email protected]
Re: King Island Abattoir
Brief regarding 2 phase proposal, the first phase being two dams (9ML Anaerobic dam and 20ML Aerobic dam) and the second
phase is construction of a 4 kilometres Ocean Outfall Pipeline from the two dams near the Abattoir. The survey was conducted
on the 4th August 2010 by Vernon Graham a Senior Aboriginal Heritage Officer; in relation to the area proposed for the two
dams and also the proposed easement for the pipeline. Regarding the two proposals these will be in two stages, just dealing with
the first phase of the project proposal.
However in reference to the second phase of the proposal there needs to be discussions with Tasmanian Aboriginal Land & Sea
Council and possibly the Tasmanian Aboriginal Centre, prior to the assessment there was discussions with the Senior Aboriginal
Heritage Officer of the Tasmanian Aboriginal Land & Sea Council and they indicated that there was a known Aboriginal site
within the region of the proposal and there would be a need to conduct a TASI (Tasmanian Aboriginal Site Index) search.
The methodology in dealing with the area being surveyed to identify incidences of Aboriginal Archaeological (Heritage) values,
the topographical layout of the land and the variation of ground visibility;
•
Walking the proposed areas of the dams and the easement concerning the pipeline to identify incidences of Aboriginal
Heritage/Relics.
•
Potential areas / pads of Aboriginal Archaeological sensitivity if needed.
•
If any site is located it‘s recorded and GPS datum used is GDA 94.
Findings regarding the first phase being the 9ML Anaerobic dam and 20ML Aerobic dam located south of the Abattoir, this area
has been highly disturbed there had been test pits dug in reference to layout of the soil profiles, this made visibility quite good
and there was no evidence of any heritage values in the areas of the two proposed dam sites, (see attached print).
This is a brief on the survey findings and there will be a need for a full report to be done in regards to the consultation process
with the Aboriginal community to review the survey outcomes for comment.
However in regards to the first phase retaining to earth works if they proceed and there is quarries concerning Aboriginal heritage
the following applies;
84
•
That works cease if any there is any quarries regarding Aboriginal heritage.
•
Contact either TALSC and or the AHT Aboriginal Heritage Tasmania.
All Aboriginal sites, along with other important landscape values and cultural resources, are an integral part of Aboriginal
Cultural/Heritage values and should be managed. Any Aboriginal site/s is to be afforded legal protection from the following
legislation.
Legal requirements
In compliance with the Aboriginal Relics Act 1975, as contained under Section 2 (3 a, b, c ) and (4) of the act, interpretation of
the term relic is as follows:
(3) For the purposes of this Act, but subject to the following provisions of this section, a relic is—
( a) any artefact, painting, carving, engraving, arrangement of stones, midden, or other object made or created by any of the
original inhabitants of Australia or the descendants of any such inhabitants;
( b) any object, site, or place that bears signs of activities of any such original inhabitants or their descendants; or
( c) the remains of the body of such an original inhabitant or of the descendant of such an inhabitant who died before
the year 1876 that are not interred in—
( i) any land that is or has been held, set aside, reserved, or used for the purposes of a burial-ground or cemetery
pursuant to any Act, deed, or other instrument; or]
( ii) a marked grave in any other land.
As part of the client / proponent has an obligation to the Tasmanian Aboriginal community in accordance with the Aboriginal
Relics Act 1975, as contained under Section 14 (1).
Except as otherwise provided in the Act, no person shall otherwise than in accordance with the terms of a permit granted
by the Minister on the recommendation of the director—
(a) destroy, damage, deface, conceal, or otherwise interfere with a relic.
If there’s any concerns please do not hesitate to call.
Thank You
Sign
Vernon Graham
Senior Aboriginal Heritage Consultant
& being the Principal of Palawa Heritage Services Pty Ltd
Cc: Colin Hughes the SAHO of TALSC, and
Forward Email to Aboriginal Heritage Tasmania
85
Appendix J – Biogas Monitoring
86
87
Swift
T +61 3 93164732
Appendix K – Climate Data
[email protected]
www.jbsswift.com.au
Appendix L – Odour Dispersion Assessment
Swift
T +61 3 93164732
[email protected]
www.jbsswift.com.au
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
Swift
T +61 3 93164732
[email protected]
www.jbsswift.com.au
107
108
Swift
T +61 3 93164732
[email protected]
www.jbsswift.com.au
110
111
112
113
114
115
116
117
118
Appendix M – Soil Test Pits (1-3) results
119
120
121
Appendix N – Expected Acoustical Impact of New Aerator and Flare
122
123
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Development Proposal and Environmental

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