Hong Kong： Refining waste cooking oil into biodiesel

　　As an international food capital, Hong Kong is full of restaurants, attracting many diners from all over the world. In this era of worrying food safety, Hong Kong has already issued regulations on the management of waste oil and food waste in restaurants, and has kept the kitchen waste at all levels from the source to the end to prevent the waste oil from flowing back to the table, so that diners can have peace of mind.

　 　 Filtration and separation of food residues to build a grease trap

　　If we carefully observe the parking lots or underground floors of many Hong Kong buildings, people will find that there will be a square stainless steel tank with a size of about 10 cubic meters in the corner, which is connected with pipes leading to a certain part of the building. This stainless steel tank is a common grease trap in many restaurants and industrial buildings in Hong Kong. "It is necessary to build a grease trap, otherwise it is impossible to get a food license." There was such a law in Hong Kong decades ago, which is also a way for many restaurants in Hong Kong to dispose of kitchen waste.

　　There are many fried and roasted dishes in Cantonese cuisine, which produce a lot of oil every day. After cooking, the oil needs to be replaced every day. The restaurant simply filters it and pours it into the oil drum, waiting for the recycling company to come to the door for recycling. According to Hong Kong’s Water Pollution Control Ordinance, the grease in food residue should be filtered and collected by oil separator.

　　The Environmental Protection Department of the Hong Kong Special Administrative Region explained that the direct discharge of food residues into sewage pipes would lead to the accumulation of oil dirt, and the drainage pipes would be blocked and stink, which would affect the environmental sanitation of restaurants and the surrounding areas. Therefore, restaurants in Hong Kong need to establish a grease trap to filter sewage again and collect grease. The collected waste oil is recycled by a special recycling company, and the Environmental Protection Department of the Hong Kong SAR Government also records and checks the relevant treatment of restaurants to prevent the possibility of waste oil flowing back to the dining table. According to the Food and Environmental Hygiene Department of the Hong Kong Special Administrative Region, from the results of earlier spot checks, there was no use of waste oil in restaurants in Hong Kong.

　　Production of diesel oil by recycling food waste oil

　　So, where will these separated and recycled waste oils go? In Hong Kong, waste oil is regarded as a commodity sold by restaurants to recycling companies, so recycling companies need to pay restaurants, and waste oil has been professionally treated.

　　In a free market like Hong Kong, recyclers will certainly not do business at a loss. The waste oil produced in restaurants brings business opportunities to recyclers. Biodiesel which can be used as automobile fuel can be produced by treating, reacting and separating the waste oil. As a new fuel with environmental benefits, biodiesel can help reduce carbon dioxide emissions, and it is now being widely promoted in western countries.

　　In order to encourage the use of biodiesel, the Hong Kong SAR Government has introduced a tax-free preferential policy for automobile biodiesel to further promote the recycling of food waste oil. At present, there are three biodiesel producers in Hong Kong, which regularly collect waste oil from restaurants, properly collect it and transport it to factories for processing to generate biodiesel.

　　From the filtration and separation of food residues to the recovery and treatment of waste oil, the Hong Kong SAR Government monitors the flow of waste oil at the source, encourages recycling at the end, and promotes the application of new fuels. In this way, waste oil can’t be quietly sold underground, but as a commodity to continue its use value. (Cao Haiyang Intern Ji Menghui)