The UTS Institute for Sustainable Futures investigated the feasibility of anaerobic digestion to manage organics waste streams in the heart of urban Sydney, in collaboration with Flow Systems, JLL, Avac and Active Research and with support from the City of Sydney's Innovation Grant program.
Sydney is growing fast. The current population is 5 million. This is expected to grow to 8 million by the middle of the century, predominantly through urban densification. As Sydney grows the highly siloed and traditionally centralised, linear model of water and waste service provision, where resources are imported into the city and waste exported, will need to change.
A key issue of concern is the generation of organic waste streams, in particular food waste, most of which is currently sent to landfill with associated economic, environmental and social consequences. A potential solution is to capture and treat organic waste products locally, turning them into valuable resources such as energy and nutrient rich soil conditioner.
This project investigated the feasibility of a vacuum and anaerobic digestion system to transport and process food waste and other organic waste materials (sewage, fats, oils and grease) on-site to generate:
- biogas as a renewable energy for use on-site and
- nutrient rich digestate for beneficial reuse as a soil conditioner.
Central Park, in the heart of Sydney, is an award winning precinct development owned by Frasers Property Australia. Built on the former Carlton United Brewery site, the $2 billion, 5.8 hectare, 5 star Green Star development will be completed in 2018 and have 11 buildings, 33 heritage items, a 6,400 sqm public park and 1,200 sqm of green walls consisting of 35,000 plants from 350 different species. The 255,500 sqm gross floor area covers residential (58%), commercial (30%) and retail (12%) with approximately 5,300 residents and 1,750 workers.
One Central Park is the focal point of the study. The site has over 600 apartments and currently over 50 active retail spaces with over 20 food establishments ranging in size from a large supermarket on the lower ground floor, recently opened cinema on the upper floor, and smaller food outlets and restaurants across the retail space. Both the residential and commercial components of the site present a significant opportunity for separating and collecting food waste as a feedstock for an anaerobic digestion system.
The basement of the building houses the $13m one ML/d water recycling plant, the largest in the basement of a residential building in the world. Flow Systems, the key partner in this project, is the private utility manager of the site, providing water, wastewater, water recycling services and energy services through the on-site tri-generation Central Thermal and Electricity Plant in an adjacent building. The water recycling plant discharges thousands of litres of sewage sludge every day, representing a potential source of feedstock to an on-site anaerobic digester. In addition, other organic waste streams such as grease from grease traps, used cooking oil (UCO) and cuttings from the vertical green walls are also collected and treated off-site presenting potential material for anaerobic digestion.
With over 20 food retailers and over 600 apartments producing food waste, the combination of organic food waste, vegetation from the green walls, trade waste and fats, oils and grease provide a significant opportunity to examine the potential for energy generation and use on-site through anaerobic digestion.
The project was funded by the City of Sydney under the Environmental Performance – Innovation Grants Program. Additional funding and in-kind support was provided by the project team, comprising:
The study commenced in mid 2017 and was completed in December 2018.
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