Resource Recovery With Wollongong Water Recycling Plant as a Case Study

Transcription

1 Resource Recovery With Wollongong Water Recycling Plant as a Case Study

2 Presentation overview Overview of Sydney Water and our services Biosolids Energy Recovery» Cogeneration» Codigestion Wollongong WRP Case Study: Biosolids Cogeneration Recycled Water

3 We re Australia s largest water and wastewater service provider

4 Our services We test the drinking water at 650 homes each month, for more than 70 different water characteristics We treat more than 1.6 billion litres of wastewater a day through 25 wastewater systems We provide stormwater services to about ½ million people through 448 km of stormwater channels and pipes We deliver water, wastewater, some stormwater and some recycled water services to 4.9 million customers We deliver 1.7 billion litres of water to our customers

5 We collect and treat over 1.6 billion litres of wastewater a day from 1.8 million properties using: 25,000 km of pipes 30 wastewater and water recycling plants 675 pumping stations

6 Resource Recovery Waste is now a resource stream Image used from

7 How are biosolids and energy produced?

8 Details: Anaerobic Digestion Stabilization of sludge and scum through the decomposition of organic matter by bacteria in the absence of molecular oxygen. Mesophilic bacteria: 30-38ºC, (37ºC target). Sludge Residence Time approx. 20 days Volatile Solids Reduction Methane produced for Cogen

9 Biosolids Solids treatment: reduce pathogens, odours and particles that attract insects and vermin and to also remove water.

10 BEFORE BIOSOLIDS Since , we ve beneficially used 100% of biosolids produced at our wastewater treatment plants

11 AFTER BIOSOLIDS Each year we use about 180,000 tonnes of biosolids in agriculture and composting with over 40 farms across the Central West and South West of NSW using them to help improve soil, mainly in broad-acre farms

12 Biosolids NSW Health and NSW EPA have confirmed biosolids are safe if produced and used in line with the NSW EPA s Environmental Guidelines. Farm sites selected according to environmental, social and economic criteria, such as geography, proximity to houses and cost. Assessments done of environmental impacts, including soil analysis, and surface and ground water impacts. Assessments are sent to council and other key stakeholders before biosolids are applied, as required by the Guidelines. To comply, NATA accredited laboratories test all of our biosolids for contaminant levels and stability. This analysis determines the suitable beneficial use market.

13 Biosolids About 70% of our biosolids are land applied in agriculture and biosolids are spread at rates which are calculated using the background levels of contaminants and nutrients in the soil and the levels in the biosolids. Other 30% composted Suitable Beneficial Use Options Product Type Non-direct land app. Direct land application (site sensitivity) eg. Composting Remote Low Medium High B1 B2 B3 B4

14 Biosolids Land application Transport into storage bunds Audited by Sydney Water Loading into a spreader Spreading onto paddocks followed by soil incorporation

15 Biosolids - Land Application After incorporation Crops are sown (e.g. Oats & Wheat). No grazing or harvesting within 30 days of biosolids application Biosolids Update June July 2016

16 Biosolids - Composting Remaining 30% of biosolids are composted Blended with organic wastes such as plant material and composted following the NSW EPA Environmental Guidelines. Produces an unrestricted product.

17 Biosolids composting Mix with green wastes Compost in windrows Screened compost Grade A composted product - Unrestricted use

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19 Biosolids Farmer feedback Gordon Nash, sheep farmer on the Ulabri property at WATTLE FLAT NSW What made you decide to use them on your farm? It was an easy decision to use biosolids on my property. The soils on our farm are of poor quality and fragile, with low organic matter and poor structure, which makes pasture improvement difficult. Conventional fertilizers were only providing a short term positive effect which didn t assist with soil structure improvement and had no ongoing benefits. What kind of benefits have you experienced? The benefits of using biosolids are massive. The most important benefit though is the improvement to soil quality, including increases in organic matter and consequently, fertility. With this has come better soil structure and hence less soil fragility. Once we had been able to increase the soil fertility using the biosolids we now have better water retention, the ability to graze our sown improved pasture paddocks earlier and consequently improved production per hectare. What advice would you give to other producers who are considering biosolids? My advice to other producers who are considering biosolids is to don t think about it for too long... just get it. Get on a biosolids program as it is dynamite! (Full interview available on request)

20 Challenges for Biosolids Near treatment plants: Odour from solids processing and transport Trucks transporting biosolids away from the plant Near farms: Can be odourous during unloading and spreading Stickiness hard to spread on land & clean trucks Not easy to explain they are treated wastewater solids with stringent controls Can be perceived as Sydney dumping its waste in country areas Concern about health risks Social research to help us identify and understand community and stakeholders sentiment is underway.

21 Energy Recovery We now generate about 21% of our total energy needs through an extensive portfolio of renewable energy projects, including hydro electricity and cogeneration This reduces greenhouse gas emissions by over 60,000 tonnes a year

22 Renewable generation Enough to power over 10,000 homes each Hydro Captures excess energy from pressure reductions and gravity flows Water (Prospect / Woronora) and wastewater systems (North Head) Installed capacity 6MW Cogeneration Generation using biogas from wastewater treatment 8 wastewater treatment plants 10MW installed capacity Solar Solar PV Only recently become cost effective 160 kw at 8 sites and growing 2MW potential for Malabar & 2MW across other sites including Wollongong

23 Codigestion to increase Cogeneration Food Wastes = more Volatile Solids = more biogas = more electricity generated

24 Cronulla Commercial Food Waste Receive pulped fruit and vegetable waste from Feb 2017 Up to 70kL (3 trucks) per day (currently 10kL due to digester foaming issues) Challenges: Digesters don t like inconsistency (temp/load rates/ph/tsr) Odour control

25 Co-digestion at Wollongong No digester capacity for food waste co-digestion Glycerol co-digestion not financially viable No current capacity in engine Engine capacity can be increased at the 60,000hour service Waste gas burner capacity limited

26 Future opportunities? Co-digestion to biomethane Codigestion to increase gas generation and upgrading of biogas to biomethane for use as a transport fuel, displacing fossil fuels. GENeco bio-bus Bristol UK

27 Wollongong WRP: Energy Use Yearly Usage 13,552MWh Spend $1.14 million

28 Case Study of Wollongong WRP: Cogeneration Currently offsets plant use ~30-35% Upgrade from a 530kW engine to a 630kW engine in 2018 Negated daily need for Digester Boilers

29 Case Study of Wollongong WRP Improvements to gas storage: 2 of 6 Digester now have membrane covers 3 times gas storage than conventional lids Improves utilisation of Cogen Less fugitive gas emissions Corrosion proof

30 Case Study of Wollongong WRP: Biosolids Coming Improvements to Biosolids production: Existing Hi G centrifuges to Rotary Screw Press 5kW drives instead of 45kW Removes noise Replace Screw conveyors with Belt conveyors Challenges: Heavier & Larger footprint than Centrifuges to match capture & feed rates Higher Operational costs for liquid Polymer Higher wash water volumes

31 16 Recycled Water Schemes 7,677ML Recycled Water supplied 2016/17

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33 Case Study of Wollongong WRP: Recycled Water

34 Wollongong WRP: Recycled Water Uses 1-2ML on site reuse BlueScope Steel 20ML/day Reverse Osmosis Port Kembla Coal Terminal. 1-2ML/day Wollongong Golf Club ~ 0.7ML/day, Wollongong City Council ~0.1ML/day

35 Case Study of Wollongong WRP: Recycled Water Micro Filtration (0.2 micrometer) 5 Reverse Osmosis skids 20ML/day Old Reverse Osmosis membrane

36 Conclusion: Wastewater is now a resource = Biosolids Electricity Recycled Water Contact welcome: hugo.figgis@sydneywater.com.au

37 By 2031, across greater Sydney, we can expect: an extra 1.3 million people over 570,000 new homes 600,000 new jobs

38 BEFORE We ve invested over $3 billion over the past 25 years in wastewater treatment, including deep ocean outfalls, to improve water quality along the coast

39 Whales, dolphins and other sea life have returned to the harbour and the ocean off Sydney and Illawarra beaches, adding to the unique lifestyle that all Sydneysiders enjoy AFTER