Analysis Of Sewage Discharge Fluctuation Characteristics And Its Application In The Determination Of Emission Limits

China's water pollution control system is an important system of water management,November 10,2016 the State Council issued a "pollutant discharge permit implementation of the program," in 2017 to complete the "Water Pollution Prevention Action Plan" key industries and overcapacity industries and enterprises Emission permits issued in 2020,the basic completion of the national sewage permit issued,marking the implementation of China's sewage permit system has entered a new stage.It is one of the most important tasks of the discharge of pollutant discharge permits.The paper studies the characteristics of wastewater discharge fluctuation and its influence on the determination of emission allowances,and adapts to the management requirements of water environment protection in the new situation.Practice shows that by the changing production and living activities,pollution sources of sewage behavior is not to maintain stability,but in a constant fluctuation,showing a different cycle of the law of fluctuations.Therefore,even if the total discharge of long-term pollutants remains the same,a large number of pollutants in the short term emissions may also have an adverse impact on environmental quality;the same time,taking into account the regulatory convenience,but also need different periods of pollutant emissions.From the domestic and foreign sewage permit implementation experience,in addition to the provisions of the annual emissions,but also according to the actual need to develop monthly,weekly,daily and other periodic emission permits limits.Due to historical reasons,China's total pollutant control targets are often based on annual emissions as a control target,but the lack of a shorter period of pollutant emissions regulations,it is necessary to study the characteristics of sewage discharge fluctuations,determine the different cycle of sewage The relationship between the permissible limit for the discharge of the permit limit to provide technical support.This paper presents a case study of typical industries in Tieling and Changzhou.Considering data availability and industry representative,this paper studied slaughtering and processing,coal mining and sewage treatment in Tieling City,and studied the fluctuation characteristics of sewage discharge in the same industry in different industries.Based on Changzhou sewage treatment,chemical,textile and electroplating Industry as the object,studied the characteristics of pollutants discharge fluctuation in different industries.The paper provides the reference value of the fluctuation characteristic for each index of different industries in Tieling city and Changzhou city,which can provide scientific basis for other enterprises in similar industries to determine the limit of pollutant discharge in different periods.In this paper,the application of pollutant emission fluctuation characteristics in emission control is studied,which provides a scientific basis for the determination of the limit value of pollutant discharge in different time periods.Through the above research,the paper mainly draws the following conclusions:(1)The fluctuation of pollutant emission in typical industries of Tieling City is related to the characteristics of the industry and the scale of the enterprises.From the industry point of view,the pollutants day,week,monthly emissions and annual emissions of the ratio are met ?MDL >?AWL >?AML;from the enterprise scale,the general displacement of the larger,? average smaller,more stability,But when the displacement exceeds a certain scale,its influence on the value of ? weakened,? value vulnerable to other factors.(2)The fluctuation characteristics of pollutants in different industries in Changzhou are obviously different.The fluctuation of CODCr concentration is small and the fluctuation of TP is comparatively large,and the correlation between them is not obvious.The NH3-N concentration in the sewage treatment plant is small,N concentration when the annual discharge of sewage is less than 10 million tons,the volatility affected by the larger scale,greater than 10 million tons,the volatility is relatively small,and emissions are more stable.Chemical industry and textile industry,large volatility,but the concentration of CODCr small fluctuations in emissions is relatively stable.Chemical industry because of its sub-industry complex,the paper also studied the different sub-sectors of pollutant emissions volatility,which electroplating industry,large fluctuations in emissions,emissions are unstable;other indicators of metal volatility is small,but still need to data further research.(3)According to the law of pollutant emission fluctuation,the limit of pollutant emission limit is determined.When there is online monitoring data,can be used directly to determine the sewage monitoring unit on-line monitoring data exceeded emissions.When there is no on-line monitoring data,we can refer to the characteristics of pollutant fluctuation in on-line monitoring data of similar industries or build the statistical model of volatility,and determine whether the pollutant discharge is excessive according to the probability statistic characteristic of monitoring value to discharge limit ratio.