from nov. 8 to nov. 14, 2018, the fifth central eco-environmental protection supervision group carried out on-site inspections in luzhou city, sichuan province. it was found that the supervision and rectification work of the city was weak, the construction of environmental infrastructure was lagging behind, the problem of illegal sewage discharge by key enterprises was prominent, and a large number of sewage was discharged directly into the yangtze river.
i. basic information
luzhou city, located in the upper reaches of the yangtze river, is the intersection of the yangtze river and tuojiang river, its first tributary. the feedback from the first round of central environmental protection supervision in 2017 pointed out that the key work in some areas of tuojiang river basin was not propelled properly, the quality of water environment declined obviously, some sewage treatment plants that should be revamped were not completed on schedule, and the construction of township sewage treatment plants was lagging behind.
sichuan province's rectification plan is clear: we should focus on the implementation of water pollution prevention and control planning in minjiang and tuojiang river basins, and accelerate the construction of municipal domestic sewage treatment facilities. luzhou rectification plan is also clear: to establish and improve the regulatory mechanism of sewage treatment industry, strengthen operation management, ensure the normal operation of sewage treatment facilities.
ii. existing problems
(1) the construction of municipal domestic sewage treatment facilities is lagging behind.
the three districts of jiangyang, longmatan and naxi in luzhou city are adjacent to the yangtze river and tuojiang river, with a permanent population of about 1.52 million. due to the insufficient capacity of urban sewage treatment, more than 600,000 people can only collect and dispose of domestic sewage through township and rural sewage treatment facilities. however, at present, the capacity of sewage treatment in villages and towns is seriously inadequate, only about 16,000 tons per day, which leads to the direct discharge of most domestic sewage in the region. inspection also found that the design and treatment capacity of luzhou east and south sewage treatment plants are 50,000 tons/day, but the concentration of chemical oxygen demand in influent water is lower than 100 mg/l for a long time, the effective collection rate of domestic sewage is less than 50%. most of the sewage interception branch pipes in service area are missing, and some streets and towns have serious problems of rainwater and sewage confluence and confluence. the sewage pipe networks built are mixed, staggered, damaged and blocked. serbia and other issues are very prominent.
due to the long-term blockage of filter barriers at the entrance of branch pipes, nearly 1000 tons of sewage are discharged directly into the yangtze river every day in laoyingqiu municipal sewage canal of longmatan district. the concentration of chemical oxygen demand, ammonia nitrogen and total phosphorus in sewage reaches 470 mg/l, 21 mg/l and 4.78 mg/l respectively, which are more than 10 times higher than the surface water standard v.
(2) the problem of illegal discharge of pollutants by some key enterprises is serious.
on-site inspection found that luzhou laojiao co., ltd. is a large state-owned listed company in luzhou city. the actual influent cod concentration of the sewage treatment station in luohan brewery base was higher than the designed treatment concentration for a long time, which resulted in a large number of dead mud floating in the biochemical pond, together with the old dosing system, uneven mixing of chemicals, and long-term abnormal operation of sewage treatment facilities.
due to the breakdown of the pipe network, some sewage directly leaks out to the municipal sewage drainage channel. the concentration of chemical oxygen demand, total phosphorus and suspended solids in the seepage sewage reaches 345 mg/l, 27.5 mg/l and 80 mg/l respectively, which exceed the industry direct discharge standard limits. the concentration of chemical oxygen demand and total phosphorus exceed the standard by 2.45 times and 26.5 times, respectively.
according to the requirement of eia approval, the sludge from the wastewater treatment in luohan brewery base should be sent to the boiler for incineration. however, the enterprise never carried out the incineration. instead, the sludge should be mixed into the domestic waste and landfilled by the municipal sanitation landfill. there is no disposal agreement and transfer form. in january 2018, through lichun machinery and equipment company, the enterprise signed a sludge landfill contract with limin environmental sanitation service department of longmatan, but did not follow up the disposal situation. the latter actually dumped sludge directly into nursery base, causing potential environmental pollution.
in addition, the luzhou guojie distillery, which is separated from luohan brewery base, drains the wastewater directly into the rainwater pipe network of the factory area and eventually discharges it into the yangtze river through the municipal sewage canal. the concentration of cod in the wastewater reaches 1700 mg/l.
3. cause analysis
the government and relevant departments of luzhou city have not paid enough attention to the supervision and rectification work and failed to implement it; they have not invested enough in the construction of environmental infrastructure and promoted it poorly, and a large number of domestic sewage has been discharged directly into the yangtze river and tuojiang river for a long time; and they have not done enough in the environmental supervision of key industrial enterprises, resulting in long-term problems of illegal sewage discharge.
source: polaris environmental protection network
legal statement: if there is any infringement, please contact qingquan to delete it at the first time.
