Domestic Wastewater Treatment System Process Equipment Sewage Management Plant

The most commonly used consumables in sewage treatment plants

In the process of sewage treatment, we should use the following agents:

(1) Oxidant: liquid chlorine or chlorine dioxide or hydrogen peroxide,

(2) Defoaming agent: the amount is very small;

(3) Flocculant: polyaluminum chloride or anionic and cationic polyacrylamide, also known as anionic pam or cationic pam,

(4) Reducing agent: ferrous sulfate hydrate and so on;

(5) Acid-base neutralization: sulfuric acid, quicklime, caustic soda, etc

(6) Chemical phosphorus removal agents and other agents.

Physical method: remove insoluble suspended solids and oil in wastewater by physical or mechanical action; Filtration, precipitation, centrifugal separation, floating, etc.

Chemical method: adding chemical substances, through chemical reactions, change the chemical or physical properties of pollutants in wastewater, so that it changes in chemical or physical state, and then removed from the water; Neutralization, oxidation, reduction, decomposition, flocculation, chemical precipitation, etc.

Physical chemical method: the use of physical and chemical comprehensive action to purify wastewater; Stripping, stripping, adsorption, extraction, ion exchange, electrolysis, electrodialysis, reverse dialysis, etc

Biological method: the use of microbial metabolism, the oxidation and degradation of organic pollutants in wastewater into harmless substances, also known as biochemical treatment method, is the most important method to treat organic wastewater; Activated sludge, biological filter, living rotary table, oxidation pond, anaerobic digestion, etc.

Among them, the biological treatment method of wastewater is based on the method that microorganisms transform complex organic matter into simple matter and toxic substance into non-toxic substance through the action of enzymes. According to the different oxygen requirements of the microorganisms that play a role in the treatment process, biological treatment can be divided into two types: good gas (oxygen) biological treatment and anaerobic (oxygen) biological treatment. Good gas biological treatment is in the presence of oxygen, by the role of good gas capillaria to carry out. Through their own life activities -- oxidation, reduction, synthesis and other processes, bacteria oxidize part of the absorbed organic matter into simple inorganic matter (CO2, H2O, NO3-, PO43-, etc.) to obtain the energy required for growth and activity, and convert the other part of organic matter into the nutrients required by organisms to make their own growth and reproduction. Anaerobic biological treatment is carried out in the absence of oxygen by the action of anaerobic microorganisms. When anaerobic bacteria degrade organic matter, they need to obtain oxygen from CO2, NO3-, PO43- and so on to maintain their own material demand for oxygen, so their degradation products are CH4, H2S, NH3 and so on. To treat wastewater by biological process, the biodegradability of pollutants in wastewater should be analyzed first. There are mainly three aspects: biodegradability, biotreatment conditions, and the limit allowable concentration of pollutants that have inhibitory effect on microbial activity in wastewater. Biodegradability refers to the extent to which, through the life activities of organisms, the chemical structure of pollutants can be changed, thus changing the chemical and physical properties of pollutants. For good gas biological treatment refers to the possibility of pollutants being converted into CO2, H2O and biological substances by microorganisms through intermediate metabolites and the conversion rate of such pollutants under good gas conditions. Microorganisms can effectively decompose organic pollutants only under certain conditions (nutritional conditions, environmental conditions, etc.). The correct choice of nutritional and environmental conditions can make the biological decomposition proceed smoothly. Through the study of biological processing, it is possible to determine the range of these conditions, such as pH, temperature, and the ratio of carbon, nitrogen, and phosphorus.

In the research of water resources recycling, people pay great attention to the removal of various nano-micron particle pollutants. Nano-micron particle pollutants in water refer to fine particles with a size less than 1um. Their composition is extremely complex, such as various fine clay minerals, synthetic organic matter, humus, oil and algae substances, etc. As a carrier with strong adsorption force, fine clay minerals often adsorb toxic heavy metal ions, organic pollutants, pathogenic bacteria and other pollutants on the surface. Humus and algae substances in natural water can form chlorinated hydrocarbon carcinogens with chlorine in the process of chlorine disinfection in water purification treatment. The existence of these nano-micron particle pollutants not only has a direct or potential harmful effect on human health, but also seriously deteriorates water quality conditions and increases the difficulty of water treatment, such as in the conventional treatment process of urban wastewater. As a result, the floc of the sedimentation tank floats upward and the filter tank is easy to penetrate, resulting in the decline of effluent quality and the increase of operating costs. The traditional conventional treatment technology can not effectively remove these nano-micron pollutants in water, and some advanced treatment technologies such as ultrafiltation membrane and reverse osmosis are difficult to be widely used due to high investment and cost. Therefore, there is an urgent need to research and develop new, efficient and economic water treatment technology.