How to treat industrial sewage in the United State

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How to treat industrial sewage in the United States has become an inevitable problem for urban development. In China, the cost of sewage treatment is higher than that of secretly discharging sewage, so that many enterprises would rather risk secretly discharging sewage, causing a direct impact on the lives of nearby residents. So, in developed countries, how do they deal with industrial pollution

for the centralized treatment of industrial pollutants, the United States has adopted the clean water act to reduce pollutant emissions and restore and maintain the integrity of national waters

the clean water law has two main control objects: the subjects whose pollutants are directly discharged into surface water are controlled by the National Pollutant Discharge Elimination System; Indirect emitters who discharge pollutants into the centralized sewage treatment system are subject to the control of the national pretreatment project. The pretreatment project requires that the indirect discharger shall obtain a sewage discharge permit before discharging his sewage into the treatment plant. The permit usually requires the enterprise to pretreat the pollutants before discharging them into the centralized treatment system, and make specific requirements for the effluent quality

the clean water law fully recognizes the impact of industrial pretreatment on the operation of centralized sewage treatment system from the very beginning. As we all know, some pollutants will interfere with the operation of the sewage treatment plant, causing the wastewater to be directly discharged into the water body without treatment or adequate treatment. Although the sewage treatment plant has the ability to remove pollutants under low load, when the load is excessive, the treatment capacity of the sewage treatment plant will become worse, and the excessive pollutants will enter the water body or sludge

in order to avoid the above situation, the United States has established strict pretreatment regulations in the clean water act. The national pollutant discharge elimination system is mainly aimed at large-scale centralized sewage treatment systems with a treatment capacity of more than 5million gallons/day (about 19000 tons/day) and small-scale sewage treatment systems that may affect the treatment effect

government led Pretreatment Project

the pretreatment regulations of the environmental protection agency are divided into various levels, including federal, state, local governments, enterprises and the public. Since its promulgation in 1978, the regulations have undergone many revisions

unlike most other environmental projects led by the federal and state governments, pretreatment projects are mainly allocated to local governments. Specifically, the centralized treatment system (public sewage treatment plant) itself is the primary management organization of the project. When the public put forward higher requirements for the friction coefficient of the film, the pretreatment plan formulated by the sewage treatment system was approved, it was given the right to control the indirect discharge of industrial users, and the state government or the Environmental Protection Bureau approved the details of the pretreatment plan

a public sewage treatment plant must make a lot of preparations to obtain the permission to implement the pretreatment plan. It is necessary to clarify the names and locations of all enterprises discharged into its treatment system, identify the nature and amount of pollutants of each sewage discharge enterprise, inform the sewage discharge enterprise of its pretreatment limits and requirements, receive and analyze the enterprise's reports, sample and measure the enterprise's sewage, assess the needs of the emergency control plan, and inspect the sewage discharge enterprises on time, Investigate the causes of non-compliance, etc. Most importantly, public sewage treatment plants must take the form of public notification and public participation to ensure the transparency of their operation

even if the WWTP is authorized to operate its pretreatment project, the state government or the environmental protection agency still has the right to supervise the implementation of the project and enforce the law. Pollutant discharge enterprises shall set clear emission limits

all enterprise users must comply with the prohibitions in the pretreatment regulations and implement standard limits based on concentration or yield. Where feasible, the environmental protection bureau gives priority to the use of pollutant emission limits per unit product, which can avoid the situation that enterprises reduce the pollutant concentration through dilution without actual treatment

in order to set the limit of pollutant discharge permit, public sewage treatment plants should first identify all enterprises discharged into their treatment system, identify the nature and total amount of pollutants discharged, and then judge which pollutants may cause penetration, interference or sludge pollution

the so-called penetration means that the public sewage treatment system is unable to treat a certain pollutant, so that the pollutant can be directly discharged into the navigable waters through the public treatment system without any transformation or degradation. Interference refers to the destruction of the operation of the public sewage treatment system by the separate or combined discharge of pollutants

with the help of this information, the sewage treatment plant conducts a technical evaluation and determines its maximum treatment load. Under the load according to the general provisions for quality inspection of gear materials and heat treatment (gb/t8539-2000) and the inspection standard for carburized and quenched automotive gears (qc/t262-1999), the treatment system can receive the sewage discharge from all licensed enterprises, while ensuring that the treatment plant itself complies with the license to avoid penetration and interference. After deducting the background source emissions from the maximum treatment load, the remaining industrial load shall be equally distributed or distributed to each enterprise as required. The environmental protection bureau provides sufficient technical guidance to assist the public sewage treatment plant to carry out this work

according to the pretreatment standard of the US Environmental Protection Agency, key industrial sources and ordinary industrial sources are distinguished according to the potential negative impact, and these two types of polluters are supervised respectively. Key industrial sources face more substantial requirements

the WWTP has the right to supervise and enforce the law

all key enterprise sources must have valid licenses, which make specific provisions on the effluent limit, the two adjustable support monitoring requirements at the back of the self rotating instrument, sampling, reporting, notification and record keeping. The public sewage treatment plant shall supervise and inspect all key enterprise sources at least once a year, and have the right to take necessary samples to verify the compliance of their pretreatment standards

when an enterprise discharges pollutants in violation of its permit, the public sewage treatment plant has the right to order it to rectify its compliance problems. If the enterprise continues to violate the regulations, the WWTP has the right to issue a stop order to require the enterprise to stop discharging pollutants. The WWTP shall have the right to immediately suspend the discharge of pollutants by the enterprise in case of emergency where the discharge of pollutants will pose a great threat to public health or welfare

the WWTP can impose fines on illegal enterprises. The amount of fines shall comprehensively consider the degree of harm, scope of influence, duration, economic benefits, historical compliance, etc. caused by illegal acts. Finally, the sewage treatment plant may revoke the pollutant discharge permit of the enterprise, including the enterprise that fails to accurately report the pollutant discharge components and the enterprise that refuses the sewage treatment plant to conduct reasonable supervision, monitoring and sampling

in the early stage of the implementation of the pretreatment regulations, the US Environmental Protection Agency realized that in some cases, the WWTP could not implement the law enforcement. For example, political and economic pressure exerted by local officials may force sewage plant personnel not to enforce the law. After identifying this problem, the US Environmental Protection Agency strengthened supervision and formulated new regulations, requiring public sewage treatment plants to develop their own law enforcement response plans, so as to carry out law enforcement actions objectively, continuously and fairly

the public has the right to sue pollutant discharge enterprises. The Pretreatment Project encourages and promotes public supervision. Public notification or hearing is required in the process of project approval and the formulation of industrial source emission limits. The public is encouraged to express their opinions on the discharge of specific industrial sources and sewage treatment plants. If the subsequent WWTP makes any changes to the pretreatment project, it must carry out a formal project revision process, inform the public and solicit public opinions again

every year, the public sewage treatment plant shall publish a list of enterprises that have major violations in the past 12 months, and the sewage treatment plant itself needs to submit an annual report to explain its current situation and various activities carried out in the previous year, including a summary of the sewage plant's supervision, compliance and law enforcement actions in that year

all information and data submitted by industrial sources to the sewage plant must be made public and directly accessible to the public. Article 505 of the clean water law stipulates that if the sewage treatment plant fails to implement the Pretreatment Project in accordance with its license, the affected citizens have the right to sue the sewage treatment plant. If an industrial source fails to discharge pollutants according to its pretreatment standards, citizens have the right to sue the enterprise

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