Vancouver considers anaerobic digestion to tackle dog waste

The Canadian city of Vancouver is considering processing dog waste using anaerobic digestion.

Local reports suggest the city will soon hire staff to remove dog waste from dog waste bags, which residents are currently required to use before depositing the waste in designated bins.

A recent report by the Bowen Island Undercurrent stated that city tender documents reveal waste collection staff are handling up to 6,900 tonnes of dog waste every year, and additional workers are now needed to process it at city waste facilities.

Currently, dog waste is collected in plastic bags that do not quickly or easily break down, so diverting the waste from landfill has become a priority for the city. Vancouver is considering a contracted service or partnership to tackle dog waste using automated waste de-bagging with methods to separate the waste from bags for processing, direct injection into the city sewage system for processing at waste plants, anaerobic digestion or composting.

A 2018 report for Metro Vancouver regional district said dogs can, on average, produce waste of up to 0.34kg per day. The city estimates there are around 55,000 dogs, creating around 6,900 tonnes of waste.

In 2016, the city launched a pilot scheme in eight of Vancouver’s parks, which saw residents deposit dog waste into red collection bins. In 2017, the city reported that a total of more than 110 tonnes of dog waste were diverted from landfills through the initiative. The report said the method not only reduces landfill waste but also provides an opportunity to produce value-added by-products from the waste, including biofuels and soil additives.

As a result of the scheme, the city of Vancouver found there were three main dog waste processing possibilities: anaerobic digestion, composting and anaerobic digestion followed by composting. Anaerobic digestion uses bacteria to decompose organic matter, in this case, dog waste, in the absence of oxygen and produces methane and biosolids. The methane is a biofuel which can then be used to generate electricity.

The closing date for contract proposals is 17 September.

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