Water treatment mode

Basic explanation:

Water treatment refers to the physical and chemical measures taken to make the water quality reach a certain standard for use. Minimum standards for drinking water are set by the environmental protection department. Industrial water use has its own requirements. Water temperature, color, transparency, smell, taste and other physical characteristics are the basic standards to judge the quality of water. The chemical characteristics of water, such as its pH, dissolved solids concentration and oxygen content, are also important criteria for judging water quality. For example, the concentration of total dissolved solids in some grassland natural water is as high as 1000 mg/l, while Canada stipulates that the concentration of total dissolved solids in drinking water should not exceed 500 mg/L, and many industrial water also requires that the concentration should not be higher than 200 mg/L. This water, even if its physical properties meet the requirements, can not be used casually. In addition, the content of radioactive elements from nature, nuclear accidents and nuclear power plants is also an important characteristic that must be monitored.

Water treatment purpose:

The purpose of water treatment is to improve the quality of water so that it meets certain water quality standards. According to the different treatment methods, there are physical water treatment, chemical water treatment, biological water treatment and so on. According to the different treatment objects or purposes, there are two categories of water treatment and wastewater treatment. Water supply treatment includes drinking water treatment and industrial water treatment. Wastewater treatment is divided into domestic sewage treatment and industrial wastewater treatment. Among them, it is particularly closely related to thermal technology, which belongs to the scope of industrial water treatment, boiler feed water treatment, make-up water treatment, steam turbine main condensate water treatment and circulating water treatment. Water treatment plays an important role in developing industrial production, improving product quality, protecting human environment and maintaining ecological balance.

Water treatment method:

Water treatment includes: sewage treatment and drinking water treatment, and some places also divide sewage treatment into two types, namely sewage treatment and water reuse. Often used water treatment agents are: polyaluminum chloride, polyaluminum chloride iron, basic aluminum chloride, polyacrylamide, activated carbon and various filter media.

The effectiveness of water treatment can be measured by water quality standards.

The processing of raw water (raw water) in order to meet the quality requirements of finished water (domestic water, production water or dischargeable wastewater).

When raw water is processed for domestic or industrial use, it is called water supply treatment;

When processing wastewater, it is called wastewater treatment. The purpose of wastewater treatment is for the discharge of wastewater (into water bodies or land) or for reuse (see wastewater disposal, wastewater reuse).

In the recycling water system and the recycling treatment of water, the raw water is the wastewater, the finished water is the water, and the processing process has the nature of both water supply treatment and wastewater treatment. Water treatment also includes the treatment and final disposal of wastewater and sludge generated during the treatment process (see sludge treatment and disposal), and sometimes the treatment and discharge of exhaust gases. Water treatment methods can be summarized into three ways: (1) The most commonly used is to obtain the required water quality by removing some or all impurities in the raw water; ② By adding new components to the raw water, the required water quality is obtained later through physical or chemical reactions; The processing of raw water does not involve the removal of impurities or the addition of new ingredients.

Impurities in water and treatment methods Impurities in water include coarse substances, suspended substances, colloids and dissolved substances. Coarse materials such as water plants floating in rivers, garbage, large aquatic organisms, grit in wastewater, and large pieces of dirt. In the water supply project, the coarse impurities are removed by the facilities of the water intake structure and are not included in the scope of water treatment.

In wastewater treatment, the removal of coarse impurities generally belongs to the pretreatment part of water. Suspended solids and colloids include sediment, algae, bacteria, viruses, and insoluble substances that are present in water and produced during water treatment. Dissolved substances include inorganic salts, organic compounds and gases. There are many treatment methods for removing impurities from water, and the scope of application of the main methods can be roughly divided by the particle size of the impurities (Figure 1). Because the impurities contained in the raw water and the impurities allowed in the finished water differ greatly in type and concentration, the water treatment process also varies greatly.