The "residual value" of household waste: one ton of electricity can be used for two months for a family of three
Can solid wastes such as domestic garbage, medical waste, and municipal sludge be harmless, reduced, and recycled? As one of the first batch of "zero-waste cities" in the country, what experience has Chongqing "tested"? A few days ago, this reporter followed the staff of the Chongqing Municipal Bureau of Ecology and Environment into a waste-to-energy power plant to explore the good way it has taken in managing the city. Walking into Chongqing Hechuan Sanfeng New Energy Power Generation Co., Ltd., the modern waste incineration power plant area is clean and tidy without peculiar smell, and the stereotypical dirty scene and unconcealable odor of the garbage plant do not appear here. At the interview site, domestic garbage transport vehicles arrived from time to time, and domestic garbage was sent to the unloading platform and dumped into the garbage storage pit.
Waste-to-energy plants are clean, clean and odorless.
According to the relevant person in charge of the site, the steel claws of the crane in the storage pit flexibly grab, and the garbage is stored in different areas one by one, and the leachate is fully fermented and leached through 3 to 5 days, and then put into the incinerator for power generation. In this way, municipal solid waste has a "surplus value". Before the enterprise was put into operation in 2020, Hechuan domestic waste was mainly hygienic landfill, and the leachate and odor generated in the landfill needed to invest funds to support the construction of pollution control facilities. At the same time, the landfill volume is close to the design capacity, and a large amount of money needs to be invested in the closure of the site. "1,000 tons of domestic waste are incinerated every day, and the designed annual power generation is about 170 million kWh, which can meet the daily electricity needs of more than 80,000 urban households. Feng Jin, general manager of Hechuan Sanfeng, said that the power generation of one ton of domestic waste can be used for two months of electricity for a family of three. At present, Tongnan's domestic garbage is also incinerated through Hechuan Sanfeng. Domestic waste incineration power generation produces high-temperature steam, medical waste disposal needs high-temperature sterilization, and municipal sludge needs high-temperature drying treatment. In other words, three different types of solid waste disposal are connected in terms of supply and demand at high temperatures. Based on this, Hechuan Sanfeng has explored a new path of multi-span co-disposal of solid waste, realized land intensification and energy recycling, and made up for the shortcomings of solid waste management in Hechuan. "Because of the infectious nature of medical waste, the main disposal method is high temperature sterilization, and municipal sludge needs to be dried due to its high moisture content, and the disposal of both types of solid waste requires a heat source, which is our advantage. Feng Jin said.
Intelligent control room for waste-to-energy power plants.
This vision gradually became a reality in 2022. At present, Hechuan Sanfeng Construction has put into use a 5 tons/day medical waste treatment project, and a municipal sludge disposal project with a disposal capacity of 125 tons/day has been started. It is estimated that by relying on the steam generated by the domestic waste incineration project to provide a heat source for it, replacing the new boiler burning fossil energy heating method, the annual use of standard coal can be reduced by 1,700 tons, sulfur dioxide emissions by 3.78 tons, nitrogen oxides by 13.56 tons, and carbon emissions by 5,500 tons. "Add medical waste and municipal sludge disposal to the incineration power generation chain. Feng Jin said that not only will this not increase the pressure on the environment, on the contrary, the disposed medical waste and dried sludge have a high calorific value, which enters the domestic waste incinerator for incineration, and the incineration process can regenerate value. "Compared to traditional landfills, this not only reduces land use, but also turns waste into treasure and increases economic benefits. Feng Jin said that the slag after waste incineration is recycled by means of cleaning and screening, and then handed over to downstream enterprises for brick making to realize the resource utilization of solid waste. "The project has achieved intensive land use, synergy in waste disposal, and recycling in energy. At the same time, it extends the industrial chain of waste incineration, provides a foundation for building a comprehensive venous industry, and is a new way to solve solid wastes such as domestic waste, municipal sludge, and medical waste. The relevant person in charge of the Hechuan District Ecological Environment Bureau said that the next step will be to further improve the solid waste treatment and disposal system, continue to improve the level of solid waste resource utilization and harmless disposal capacity, and actively build a "waste-free city" to build an example of Hechuan.
