From food waste to fertiliser

Waste management company JJ Richards & Sons’ waste reception centre in Sydney transforms commercial and retail food waste into green energy and fertiliser for agricultural use.

Located in Seven Hills, the plant uses CST Wastewater Solutions’ KDS multi-disc fine screening and compaction technology as part of its automated process that turns pulped waste from Pulpmaster’s collection tankers into a cake form. According to the company, this is more than 50% lighter and dryer than the pulp and can be transported to users for half the cost.

Waste producers using the system get monthly reports on how much they are saving on disposal costs, while simultaneously reducing their environmental impact. The material is used by farms and other agricultural enterprises as high-potency fertiliser and for the production of biogas to reduce their environment footprint.

“The system not only disposes of an environmental headache and cost for responsible businesses — including high landfill costs and the high cost of transporting waste to somewhere remote, secure and non-harmful — but turns the problem into an environmental asset, and a cost saver,” said Ben Martis, JJ Richards & Sons NSW/ACT Operations Manager, Liquids.

“Businesses love getting the reports on the environmental benefits of their waste disposal and recycling, because they can demonstrate benefits to the community, while also saving themselves substantial measurable costs.”

The Seven Hills plant features twin 28-tonne filtrate receival tanks and similarly large vessels to process waste to the pH levels most ideal for recycling uses and injection into the ground as fertiliser.

The automated receival, processing and despatch facility features high speed drive-in pulp receival bays and treatment tanks for the thousands of tonnes of throughput delivered by Pulpmaster tankers, which employ an environmentally friendly collection system that converts the mixed waste they collect into pulp slurry for further processing into organic fertiliser and biogas.

A JJ Richards tanker at Seven Hills involved in the Pulpmaster process, which transforms food waste pulp into organic fertiliser, generates green electricity from the biogas, ensures zero waste goes to landfill and curtails oil and grease entering sewer systems. Credit: JJ Richards & Sons.

This slurry passes from the Seven Hills treatment tanks through ultrafine (1 mm) screening from CST Wastewater Solutions before passing through the KDS dewatering and liquid separation process, which transforms the sloppy pulp waste into a hygienic, compact and lighter dewatered output. This is automatically fed into 35-tonne slide-out waste handling bins for loading onto JJ Richards onward delivery vehicles. The KDS system can be run continuously and reliably, with low energy consumption to optimise plant output.

Martis said the KDS system “has very few moving parts, high-efficiency dewatering operation, uses little energy and doesn’t break down”.

CST Wastewater Solutions Engineer Peter Bambridge, who worked with Martis in installing, commissioning and optimising the KDS technology at Seven Hills, said transport and handling of non-processed mixed food waste can be very costly.

“Not only do you have the OH&S and environmental issues of handling and disposing of heavy, sloppy waste, but also just transporting such material to dumps can cost $150 a ton for the specialised transport involved. Some of these dumps, by their very nature, have to be major distances from the urban source of the waste, so there are big costs involved. The Pulpmaster system, combined with KDS processing, is such an intelligent alternative from JJ Richards.”

Martis said the fact that the JJ Richards system has been proven in NSW — which has some of the strictest waste handling regulations in Australia — suggests that it is also suitable for other areas of the country.

“This is a proven system now. We are handling huge amounts of food waste already, and the potential beyond that is far huger still. We are proud of the engineering that has gone into this system and want to see its benefits spread wider and wider.”

Top image: Heavy, sloppy food waste pulp going into the KDS solid-liquid separator emerges as lighter, drier, more hygienic and more easily transportable waste cake. Credit: JJ Richards & Sons.