The present situation and development direction of sewage treatment are analyzed

0. Introduction

With the continuous improvement of social and economic level, people's requirements for the quality of water resources are also constantly improving. For the quality of water resources, people have begun to realize the serious harm caused by water pollution to the environment and economic development. Therefore, sewage treatment has become one of the indispensable links in urban construction.

The treatment of urban sewage is not only an indispensable link in the process of urban development planning and construction, but also has a great impact on social and economic life. At present, many domestic enterprises invest less money in sewage treatment, and the technology is not perfect, which leads to the serious situation of frequent water pollution events in some areas. In addition, some local governments lack effective and reasonable management measures and scientific and reasonable systems to regulate the urban environment and treat the amount of waste water. Meanwhile, many water bodies are damaged, resulting in ecological crisis.

1. The harm of sewage

The harm caused by sewage is obvious, and the construction of sewage treatment plants in cities will also cause great harm to the environment. Its specific performance in the following three aspects:

1.1 Due to the existence of a large number of suspended matter and organic pollutants in the water layer, the water quality deteriorates.

1.2 Water pollution seriously affects people's domestic water use, production and biological development

Water pollution seriously affects people's domestic water consumption, production and biological development, so it is necessary to make full preparations before sewage discharge to avoid unnecessary losses caused by various reasons and waste of water resources [1]. At the same time, it is also necessary to take into account some factors that may cause damage to the environment: for example, human activities or industrial wastewater discharged into the ground, these are problems that cannot be ignored and need to be effectively controlled and treated accordingly. As urban sewage discharge has certain rules, the impact of different stages must be taken into account in sewage treatment [2].

2. Necessity of sewage treatment

The concept of sewage treatment refers to the separation, purification and reuse of pollutants in urban domestic sewage, so as to make them useful information and realize resource recycling [3]. In China's urban sewage treatment, the main treatment is industrial wastewater and waste gas produced in the production process. Industrial wastewater mainly comes from a large amount of ferrochrome slag and domestic waste discharged from iron and steel smelters. In addition, a large number of pollutants containing heavy metal ions such as lead, cadmium (arsenic) compounds discharged from the production process will also cause serious harm to the environment, so it is very necessary and effective to treat sewage [4].

3. China's current water treatment industry chain

Water treatment industry chain refers to the separation, purification and application of pollutants in sewage through the development and utilization of polluted water bodies for the purpose of sewage treatment, forming a series of new products and putting into production [5].

At present, there are two main models in our country: one is government-led [6]. In this case, the government departments are only responsible for formulating corresponding policies to guide the local environmental planning and construction work; The second is the enterprise model dominated by development investment which the market operates spontaneously. At present, China is mainly composed of enterprise self-produced sewage, self-purification sewage and related ancillary facilities. Due to the lack of unified planning and management, as well as the lack of complete systematic design and other reasons, a lot of resources are wasted. On the other hand, it has also led to the emergence of many problems, which have a negative impact on People's Daily life, and bring pollution and destruction to the environment. Sewage treatment is a complex system project, involving a wide range and comprehensive. Therefore, it is necessary for the government and enterprises to cooperate to complete the project [7].

4. Test items and definition of their concepts

The detection items in this experiment are TP, TN, COD, SS, and NH3-N.

TP: refers to the sum of all kinds of phosphorus in sewage, the greater the TP value, the higher the degree of pollution.

TN refers to the sum of all kinds of phosphorus in sewage, and the greater the TN value, the higher the degree of pollution.

NH3-N refers to the content of ammonia nitrogen in water, and the greater the value of NH3-N, the higher the degree of pollution.

CODcr refers to chemical oxygen demand, which is a chemical method to measure the amount of reducing substances in a water sample that need to be oxidized.

BOD5 refers to the 5-day biological oxygen demand, which means that in a certain period of time, microorganisms decompose some oxidized substances in a certain volume of water, and the greater the value of BOD, the higher the degree of pollution.