China is facing serious water pollution problems, and sewage and wastewater treatment has always been the most important part of water environment management. In recent years, with the support of policies, the sewage treatment industry has developed well, and the sewage treatment capacity has continued to increase.
Sewage wastewater includes medical wastewater, industrial wastewater, and domestic wastewater. From the perspective of sewage treatment infrastructure construction, the number of sewage treatment plants and the length of urban drainage pipelines are increasing year by year. With the possibility of the virus spreading through feces and sewage in the new crown pneumonia epidemic, higher requirements have been placed on sewage and wastewater treatment. The monitoring and testing of sewage and wastewater quality has become the basis and guarantee for sewage and wastewater treatment.
At the end of 2007, there were 883 sewage treatment plants in Chinese cities, with a daily sewage treatment capacity of 71.38 million cubic meters, and the urban sewage treatment rate was only 62.8%. As of the end of June 2019, more than 5,000 municipal sewage treatment plants (excluding township sewage treatment plants and industries) have been built in cities across the country, with a sewage treatment capacity of 210 million cubic meters per day, and the urban sewage treatment rate has exceeded 90% . It can be seen that in the more than ten years between the "Eleventh Five-Year Plan" and the "Thirteenth Five-Year Plan", the scale of sewage treatment in my country has been greatly increased.
Based on the continuous improvement of environmental protection goals and sewage treatment levels, the Ministry of Ecology and Environment has always been committed to promoting the development of monitoring technology and the improvement of standard requirements. For example, at the end of 2019, a series of new standards/standards for online sewage monitoring such as the "Sewage Monitoring Technical Specifications" were released. It will be implemented in the first half of 2020.
The composition of medical wastewater is complex. In addition to common pollutants in general wastewater, it also contains pathogenic microorganisms, toxic and harmful physical and chemical pollutants, and radioactive pollutants. In addition to some of the physical and chemical monitoring indicators-such as pH, suspended solids, ammonia nitrogen, biochemical oxygen demand, chemical oxygen demand and residual chlorine, etc.-can be monitored in real time with an online monitor. For other microbial indicators (such as fecal coliforms) there is currently no mature online monitoring program.
According to the existing sewage and wastewater discharge standards, the sewage and wastewater monitoring items we are mainly concerned about are the chemical oxygen demand CODcr, ammonia nitrogen, total phosphorus, total nitrogen, heavy metals, pH and other parameters.