Wastewater discharge needs to be upgraded with equal emphasis on both discharge and collection
Release time:2022-07-25
In the future, where should urban domestic sewage treatment plants go and how can they better assume the responsibility of pollution control? The reporter interviewed Ma Zhong, Dean of the School of Environment, Renmin University of China.
Reporter: Could you please analyze the reasons why some domestic sewage treatment plants currently do not meet the discharge standards?
Ma Zhong: Generally speaking, if a domestic sewage treatment plant does not meet the discharge standards, there are three main situations: first, the sewage treatment fee is not enough to pay for the treatment of the sewage treatment plant to meet the discharge standards; Secondly, the government has provided sufficient funds, but the sewage treatment plant itself has caused excessive emissions due to outdated management and technology; Thirdly, sewage treatment plants intentionally discharge excessive amounts or discharge without treatment in order to save costs. The domestic sewage treatment plants that originally treated pollution have caused pollution, and all three situations mentioned above exist, but a considerable part of them are due to one situation.
As is well known, treating domestic sewage to meet discharge standards requires a certain treatment cost. According to the polluter pays principle, this money requires the polluter to bear all the costs of environmental damage caused, including damage costs, disposal costs, and compensation costs. The current water fees paid by residents include sewage treatment fees. But the reality is that in many places, the standard for sewage treatment fees for residents is set too low, and the sewage treatment fees paid are not enough to support the normal operation of sewage treatment plants. In addition, various factors limit it, either the government subsidies are not sufficient, or local finances are "powerless". With "this money", the result will naturally "not look too good". Therefore, in one situation, if the domestic sewage treatment plant exceeds the discharge standard, the board cannot be completely hit on the sewage treatment plant. But the second and third situations require strengthened supervision.
Reporter: How do major developed countries solve the problem of domestic sewage treatment fees?
Ma Zhong: On the water bill of American residents, the price of 1 ton of water is usually $5 to $6, including water resource fees, tap water fees, sewage treatment fees, and rainwater treatment fees. The collection standard for sewage treatment fees is as low as $1-1.5 per ton. In many cities in the United States, the vast majority of this money is paid by residents, and some cities allocate a portion of the property tax collected for domestic sewage treatment. Even compared to the sewage treatment fees in Beijing, this charging standard is still very high. Because the discharge standards for sewage in the United States follow the principle of environmental degradation, corresponding sewage treatment costs are calculated based on this, and corresponding sewage treatment fee standards are formulated. In Europe, the standard for collecting sewage treatment fees is even higher, averaging seven to eight euros per ton.
Reporter: In your opinion, how can domestic sewage treatment plants better fulfill their pollution control responsibilities in the next step?
Ma Zhong: Firstly, we need to further improve the domestic sewage discharge standards according to the local water environment quality requirements. At present, the sewage treatment rate of urban sewage treatment plants in China has reached 90%, which means that the generated domestic sewage can be basically treated. But being able to handle it doesn't mean it's handled well. The current sewage treatment standard is far lower than the environmental quality standard. The water quality of most Rivers and Lakes in China has degraded and has basically lost the self-cleaning function. In this context, even if the domestic sewage meets the current discharge standard after treatment, it is still inferior to Class V water, which is not conducive to the improvement of the water environment. Therefore, the discharge standards should be determined based on the environmental functions and current water quality of the receiving water body, and the sewage discharged to meet these discharge standards will not cause environmental pollution, that is, the principle of environmental non degradation should be adhered to. But this standard should not be a one size fits all approach. The level of socio-economic development and water environment capacity vary in different regions, and the development of new sewage discharge standards should be based on the principle of environmental non degradation and tailored to the actual situation in each region.
Secondly, the collection standards for domestic sewage treatment fees should be formulated based on the discharge standards. Nowadays, the sewage treatment fee collection standards for residents in China are generally low, and not just a little low. It can be said that doubling the current average level of sewage treatment fee collection is not too much. The specific amount of improvement should be determined based on the emission standards for environmental non degradation, and the cost of treating pollutants from emission concentration to environmental non degradation emission standard concentration per pollution equivalent. Of course, basic domestic water for residents belongs to the category of public services and the polluter pays principle should not be fully implemented. The price gap that needs to be filled according to the new standards requires government financial subsidies. For luxury water for residents (such as swimming pools), industrial and commercial, and service industries, full cost payment should be implemented.