Taking the water system as a whole, according to the geographical distribution of towns and industrial and mining enterprises along the coast of the water system, as well as the self-purification capacity, pollution capacity and pollution status of the water system, comprehensive prevention and control measures are taken to prevent and control water pollution. It includes various engineering technology means and management measures, which have the characteristics of integrity, comprehensiveness and regionality.
Comprehensive prevention and control of water pollution is a comprehensive application of various measures to prevent and control water pollution. Prevention and control measures involve two types of engineering and non-engineering, mainly:
(1) Reducing the discharge of wastewater and pollutants, including saving production wastewater, stipulating water quota, improving production technology and management system, increasing the reuse rate of wastewater, adopting new technology without pollution or less pollution, and formulating material quota, etc. For water-deficient cities and industrial and mining areas, regional recycling water and wastewater reuse systems should be developed.
(2) Developing regional water pollution prevention and control systems, including formulating urban water pollution prevention and control plans, river basin water pollution prevention and control management plans, implementing the total amount control system of water pollutant discharge, developing sewage after proper manual treatment for irrigation farmland and reuse for industry, establishing sewage reservoirs without polluting groundwater, and low water. Periodic storage of sewage reduces sewage discharge load and conducts controlled dilution during flood period.
(3) Develop wastewater treatment technologies with high efficiency and low energy consumption to treat wastewater.
Comprehensive prevention and control of pollution refers to the comprehensive use of various measures to prevent and control water environmental pollution from the whole point of view. It is very necessary to implement comprehensive prevention and control of water pollution, because China is a country with relatively scarce water resources, and there are two manifestations: one is resource-based water shortage, the other is water-quality-based water shortage. For a long time, the purification treatment of sewage outlet based on point source control can not effectively solve the problem of water pollution. Comprehensive prevention and control of water pollution must be carried out from the overall point of view of the region and water system in order to fundamentally control water pollution and solve the problem of water shortage caused by water quality.
Why do this
The necessity and urgency of comprehensive prevention and control of water pollution are embodied in two aspects: first, the contradiction between water resources shortage and unbalanced supply and demand is prominent, and the serious pollution of water environment makes this contradiction more prominent and urgently needs to be solved;
Why is it so urgent?
Secondly, the purification treatment of sewage outlets based on point source control can not effectively solve the problem of water pollution. Comprehensive prevention and control of water pollution must be carried out from the whole region or water system, and the tail control of point source control should be transferred to the source control in order to control water pollution fundamentally.
The basic principle of sewage prevention and control is the combination of prevention, treatment and management.
Through effective control and preventive measures, the amount of pollutants discharged by pollution sources can be reduced to the minimum.
(1) For industrial pollution sources, the most effective control method is to promote cleaner production. Cleaner production refers to the advanced production technology with the smallest utilization of resources and energy and the least pollution emission. The main technical routes adopted in cleaner production include: reforming raw material selection and product design, replacing toxic and harmful raw materials and products with non-toxic and harmless raw materials and products; reforming production process to reduce consumption of raw materials, water and energy; adopting recycling water system to reduce wastewater discharge; and recycling the usefulness of wastewater. Composition, reduce the concentration of wastewater, etc. Cleaner production advocates life cycle analysis and management of products rather than end-treatment.
(2) For domestic pollution sources, effective measures can be taken to reduce their emissions. Such as promoting the use of water-saving appliances, improving people’s awareness of water-saving, reducing water consumption, thereby reducing domestic sewage discharge.
(3) For agricultural pollution sources, in order to effectively control non-point pollution sources, we must start from “prevention”. Promoting scientific fertilization and rational use of pesticides in farmland can greatly reduce the residual fertilizers and pesticides in farmland, thereby reducing the amount of nitrogen, phosphorus and pesticides contained in farmland runoff.
Through various measures to control pollution sources and polluted water bodies, the pollution sources can achieve “standard discharge” and the water environment can achieve the corresponding water quality function.
It is very difficult or almost impossible for pollution sources to achieve zero discharge. Therefore, it is necessary to properly treat polluted (waste) water to ensure that the discharge standards set by the state or local authorities are met before it is discharged into the water body. Great attention should be paid to the relationship between industrial wastewater treatment and municipal wastewater treatment. For industrial wastewater containing acid, alkali, toxic and harmful substances, heavy metals or other special pollutants, local treatment should be carried out in the plant to meet the discharge standards to the water body or the water quality standards to the urban sewer. Those industrial wastewater similar in nature to municipal domestic sewage can be treated together with municipal sewage as a priority. It is not only unnecessary but also uneconomical to set up sewage treatment facilities separately. The design of urban sewage collection system and treatment plant should not only consider the need of water pollution prevention, but also the need to alleviate the contradiction of water resources. In areas where water resources are scarce, the treated municipal wastewater can be reused for agriculture, industry or municipal administration and become stable water resources. In order to meet the needs of wastewater reuse, its collection system and treatment plant should not be too centralized, but should be close to the reuse target.
In addition, according to the characteristics of water pollution, we should actively take physical, chemical, biological engineering and other means to control pollution, so that the deteriorated aquatic ecosystem can be gradually restored.
Strengthen the supervision and management of pollution sources, water bodies and water treatment facilities in order to promote treatment. Pipe also plays an important role in water pollution control. Scientific management includes regular monitoring and inspection of pollution sources, water treatment facilities and sewage treatment plants, and regular monitoring of water environmental quality to provide basis and information for environmental management.
Functional zoning of water environment is the basis for comprehensive prevention and control of water pollution
According to the current functions of water environment and the needs of economic and social development, the functional zoning of water environment is based on surface water environmental quality standards, which is the basis of water source protection and water pollution control. For example, the surface water environmental quality standard divides the water area control functions into five categories: Class I is mainly applicable to source water and national nature reserves; Class II is mainly applicable to primary protection areas of centralized drinking water sources, precious fish protection areas, fish and shrimp spawning grounds; Class III is mainly applicable to centralized drinking water sources II. Class IV is mainly suitable for general industrial water use and recreational water areas where human body does not contact directly; Class V is mainly suitable for agricultural water use areas and waters where general landscape requires.
Principles and methods
The principles of division are as follows: priority protection of centralized drinking water source areas; water body should not reduce its current use function, taking into account planning function; water areas with multiple functions should be classified according to the highest function; professional water standard requirements should be considered as a whole; consideration should be given to each other between upstream and downstream areas, with due consideration to potential functional requirements; and rational use of water body itself. Net capacity and environmental capacity; Consider the combination of land industrial rational layout; Consider the impact on underground drinking water sources; Practical and feasible, easy to manage.
Functional zoning method: according to the principle of adapting measures to local conditions and seeking truth from facts, according to actual measurement, empirical analysis and administrative decision-making.
Controlling pollution and protecting water sources according to functional areas.
(i) The level of protection shall be defined according to the functions of the waters and the requirements for water pollution control shall be put forward. For example, special protected waters refer to the first and second categories of national Surface Water Environmental Quality Standards (GB3838-2002). No new sewage outlets shall be built for such waters. Existing sewage discharge units shall be strictly controlled by local environmental departments in order to ensure that the water quality of accepted waters meets the water quality standards for specified purposes; and key protected waters shall be protected. It refers to the third class waters stipulated by GB3838-2002, and the first class discharge standards stipulated in the Comprehensive Sewage Discharge Standard (GB8978-1996) are applied to the sewage discharged into the waters.
(ii) The total amount control shall be implemented according to the functional areas. The so-called total amount control refers to the maximum allowable emission of some kind of pollution in order to maintain the environmental target value of an environmental functional area. Therefore, water environmental functional zoning is the basis for implementing total water pollution control.
Formulating comprehensive prevention and control plan of water pollution
Main contents and working steps
(i) Based on the investigation and evaluation of water environment, the main problems of water environment are analyzed and determined.
(ii) Division of water pollution control units. According to the analysis conclusion of water environment problems, considering the administrative division, water area characteristics and pollution source distribution characteristics, the source area and receiving water area are divided into water pollution control units.
(iii) Put forward environmental objectives and demonstrate accessibility. At the Fourth Session of the National People’s Congress, the strategic goal of environmental protection across the century was clearly put forward, which is the basis for the goal of comprehensive prevention and control of water pollution. Environmental objectives should include the total amount control objectives of major pollutants and the specific objectives of various sub-items of comprehensive water environment improvement. It is necessary to demonstrate the accessibility of environmental objectives.
(iv) Determine the amount of major pollutant reduction and the proportion of reduction allocation.
(v) To formulate a comprehensive water pollution prevention and control plan and implementation plan.
(vi) Support and guarantee for the implementation of the plan. Including: analysis of sources of funds, formulation of annual plans, implementation of pollutant discharge declaration and registration and pollutant discharge permit system proposals, as well as the necessary technical support.
Several principles that must be adhered to in formulating comprehensive water pollution prevention and control plan
(i) Focusing on economic construction is conducive to the coordinated development of economy and environment.
(ii) Take rational development and utilization of water resources as the core, focusing on the whole process control. By changing the mode of economic growth and promoting cleaner production, pollution can be eliminated in the process of economic reproduction.
(iii) Overall planning, highlighting key points, adapting measures to local conditions and stressing practical results.
(iv) adhering to the principle of comprehensive improvement. Systematic analysis of the planning scheme is needed to achieve overall optimization.
Emission permit system, transition from concentration control to total quantity control
Practice has proved that in carrying out this system, we must follow the following five requirements in the light of China’s current technological level and management system.
(1) Determine the total amount control target from the actual point of view. When it is difficult to determine the environmental capacity of the receiving water body for discharging pollutants, according to the principle of the total amount control plan put forward by the State Environmental Protection Administration in December 1995, the total amount of discharged major water pollutants in 1995 can be regarded as the target total amount, and the proportion of reduction can be determined according to the actual technical and economic level of the region, and allocated to the main body. Pollution sources.
(2) Choose the target of issuing certificates. The main target of issuing permits is the large polluters in the region. A city can catch more than a dozen or dozens of households. It is necessary to select the key control points through investigation and evaluation of pollution sources. For example, Anyang City put forward that we should do a good job of 2, 5 and 8, and control 8 and 9, that is, we should catch 20, 50 and 80 large polluters in batches, and control 70%, 80% and 90% of the city’s water pollution load.
- Control the total amount of sewage. Measure according to local conditions and control the total amount of sewage.
- Strengthen environmental supervision and management after issuance of certificates.
- Pay attention to practical experience and constantly improve the level. In order to implement the sewage discharge permit system, we should first carry out pilot projects, sum up experience and gradually popularize it.
- But we should also pay attention to the new problems in the process of implementation, such as the paid transfer of pollutant discharge indicators and the trading of pollutant discharge rights.
- Comprehensive Prevention and Control of Water Pollution in Township Enterprises
- The discharge of industrial wastewater from township enterprises was only 3.9 billion tons in 1997.