What is the Proper Method of Water Waste Disposal?

The wastewater treatment method is a method for separating the pollutants contained in the wastewater or converting them into harmless substances, thereby purifying the wastewater. There are four main categories: physical wastewater treatment methods, chemical wastewater treatment methods, physical and chemical wastewater treatment methods, and biological wastewater treatment methods.

Wastewater treatment

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There are many kinds of pollutants in wastewater. It is impossible to remove all the pollutants with one treatment unit, and it often takes several methods and a treatment system composed of several treatment units to meet the requirements. According to the degree of treatment, wastewater treatment can generally be divided into three levels: the task of primary treatment is to remove suspended solid pollutants from wastewater, and various treatment units in physical treatment methods are mostly used. The task of secondary treatment is to largely remove organic pollutants in wastewater, and various treatment units in aerobic biological treatment methods are mostly used. The task of tertiary treatment is to further remove pollutants that are not removed by secondary treatment, including organic matter, phosphorus,

Physical wastewater treatment

Wastewater physical treatment method The method of separating and removing insoluble pollutants (including oil film and oil droplets) in suspension in wastewater by physical action. During the treatment, the chemical properties of the pollutants will not change. The methods are: gravity separation method, the processing unit of which has sedimentation, floating (air flotation), etc., the processing equipment used is sedimentation tank,

Substitute wastewater treatment technology can be divided into primary treatment, secondary treatment and tertiary treatment according to the degree of treatment.

(1) A treatment method that removes floating matter and partially suspended pollutants in the wastewater, adjusts the pH of the wastewater, reduces the degree of corruption of the wastewater, and the load of subsequent treatment processes. After the primary treatment, the sewage generally does not meet the discharge standards. Therefore, the primary treatment is generally used as the pretreatment, and the secondary treatment is the main body. If necessary, the tertiary treatment is performed, that is, the advanced treatment, so that the sewage reaches the discharge standard or supplement Industrial and urban water. Common methods of primary treatment include sieving, sedimentation, floatation, and pre-aeration.

(2) Secondary treatment is the treatment of sewage after it has passed the primary treatment, which is used to remove a large amount of organic pollutants in the sewage to further purify the sewage.-): Process: For a long time, biochemical treatment has been mainly used as Main process of secondary sewage treatment. Adopting chemical or physical chemical treatment as the main process of secondary treatment, and with the continuous increase of the variety of chemical agents, the continuous improvement of processing equipment and technology and promotion. As a result, secondary treatments have become meaningless as synonyms for biochemical treatments. After the first stage treatment of the sewage, some suspended matter can be effectively removed, and some of the biochemical oxygen demand (BOD) can also be removed, but generally the organic matter and oxides, sulfides, etc. in the dissolved state and colloid state in the sewage cannot be removed Toxic substances can not meet the sewage discharge standards. Therefore, a secondary treatment is required. The main process of secondary treatment is biological treatment, including anaerobic biological treatment and aerobic biological treatment. Among them, aerobic biological treatment mainly includes activated sludge method and biofilm method. Some countries are studying and adopting chemical or physicochemical treatment methods as the main treatment of secondary treatment. It is expected that these methods will be promoted with the continuous increase in the variety of chemical agents and the continuous improvement of processing equipment and processes. The secondary treatment of sewage can remove a large amount of BOD and suspended matter in the sewage, purify the sewage to a large extent, and play a certain role in protecting the environment. However, as the amount of sewage continues to increase and water resources become increasingly tight, it is necessary to obtain higher quality treated water for reuse or replenishment. For this reason, sometimes it is necessary to carry out tertiary treatment of sewage on the basis of secondary treatment.

(III) Tertiary treatment The tertiary treatment is also called advanced sewage treatment or advanced treatment. In order to further remove the pollutants that are not removed by the secondary treatment, they include microorganisms and undegradable organic matter or soluble inorganic matter such as phosphorus and nitrogen. Tertiary processing is synonymous with deep processing, but the two are not exactly the same. Tertiary treatment is one or more treatment units that are added to remove certain specific pollutants such as phosphorus and nitrogen from the wastewater after secondary treatment. As for advanced treatment, wastewater recovery A processing unit or system that is added after the secondary treatment for the purpose. The tertiary treatment is more expensive and the management is more complicated, but it can make full use of water resources. The perfect tertiary treatment consists of unit processes such as phosphorus removal, nitrogen removal, organic matter removal (mainly organic matter that is difficult to biodegrade), viruses and pathogenic bacteria, suspended matter and fused minerals. According to the specific destination of the three-stage treatment effluent, its treatment flow and constituent units are different. In order to prevent eutrophication of the receiving water body, a three-stage treatment of phosphorus and nitrogen removal is adopted; if the downstream reference water source or bath is protected from pollution, phosphorus removal, nitrogen removal, detoxification, germs and pathogens It can be used as domestic water other than urban drinking water, such as washing, cleaning, toilet flushing, spraying streets and green areas.