The Environmental Protection Department today said it will start a trial using anaerobic co-digestion technology to treat chicken waste in August, following the successful experience of using the technology to treat pig waste.

The department noted that 10 tonnes of chicken waste per day will be converted into energy in the initial phase of the trial and it may further increase the capacity for chicken waste treatment, depending on the effectiveness.

In a statement responding to media enquiries, the department said the Government has been planning to explore different technologies, including bioconversion technology, through pilot projects to treat livestock waste, for the purpose of gaining experience, collecting data, and comparing the advantages and disadvantages of various technologies and their cost-effectiveness, with a view to formulating long-term waste treatment arrangements.

The department engaged a contractor in 2021 through an open tender process to provide services for carrying out a trial in the EcoPark using black soldier flies (BSF) bioconversion technology in treating chicken waste and converting it into fish feed and fertiliser.

The contract operation period is one year and the contractor will decommission the plant and return the site after the operation period expires.

The plant was installed and started operating in February last year, processing about 10 tonnes of chicken waste per day, which accounts for one-fourth of the chicken waste generated in Hong Kong, the department said.

While the contract was originally scheduled to end in February, the department and the contractor mutually agreed to extend the operation period by six months until August to collect more data.

In the meantime, the department has successfully tested anaerobic co-digestion technology in treating pig waste and food waste at O．PARK2. Currently, O．PARK2 processes an average of 20 tonnes of pig waste per day, accounting for half of the pig waste generated in Hong Kong.

The department will utilise the data, operational experience, cost-effectiveness, and other information collected from both the BSF and the anaerobic co-digestion pilot projects to formulate long-term waste treatment arrangements for chicken waste.

As regards the use of BSF bioconversion technology for food waste treatment, the department said it is currently using anaerobic digestion to convert food waste into energy.

The department pointed out that the "Food Waste/Sewage Sludge Anaerobic Co-digestion" trial projects at Tai Po and Shatin Sewage Treatment Works currently in operation are very successful.

Given the scarcity of land resources in Hong Kong, it will focus on developing the use anaerobic digestion to enhance the overall capacity for food waste treatment in the future, because using BSF bioconversion technology or other technologies to treat large amounts of food waste would require significant additional land.