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Domestic Wastewater Treatment System Process Equipment Sewage Management Plant

Domestic sewage treatment is an important role in water resource management in urban and rural areas, with the following applications and implications:

1. Protection of water resources: through the treatment of domestic sewage, reduce the pollution of water resources and protect the sustainable use of water resources.

2. Prevention of disease transmission: The treatment of domestic sewage can effectively kill pathogenic microorganisms and reduce the risk of disease transmission.

3. Improve environmental quality: domestic sewage treatment can reduce water and soil pollution, improve environmental quality,

4. Promote sustainable development: Domestic sewage treatment can improve the utilization efficiency of water resources and promote sustainable development of urban and rural areas.

Through domestic sewage treatment, environmental pollution can be reduced, sustainable use of water resources can be protected, and people's living environment can be improved.

    Domestic sewage treatment refers to the treatment of sewage generated in the life of urban residents, so that it meets the discharge standards and does not cause pollution to the environment. The importance of domestic sewage treatment is self-evident, which is related to human health and sustainable development of the environment.

    First of all, domestic sewage contains a large number of organic matter and microorganisms, if directly discharged into the environment, it will cause serious pollution to the water body. These organic matter and microorganisms will consume oxygen in the water body, resulting in the deterioration of water quality and affecting the survival of aquatic life. In addition, domestic sewage also contains a large amount of nitrogen, phosphorus and other nutrients, if discharged into the water body, will lead to water eutrophy-causing algae blooms, affecting water quality and ecological balance

    Secondly, domestic sewage also contains a variety of harmful substances, such as heavy metals, organic matter, drug residues and so on. If these substances are directly discharged into the environment, they will cause pollution to water bodies and soil, and cause harm to ecosystems and human health. Therefore, effective treatment of domestic sewage is an important measure to protect the environment and human health

    In addition, domestic sewage treatment can also realize resource utilization. Domestic sewage contains a large amount of organic matter and nutrients, which can be converted into organic fertilizer and biogas and other resources after proper treatment, so as to realize the recycling of resources and reduce the consumption of natural resources.

    Daily life waste water, In fact, only a small part of the waste water has been treated, and most of it is directly discharged into rivers without treatment. It's worse in smaller cities.

    Faeces and so on are generally not directly discharged, but there are collection measures.
    The composition of pollutants in wastewater is extremely complex and diverse, and it is difficult for any treatment method to achieve the purpose of complete purification, and it often takes several methods to form the treatment system to meet the requirements of treatment.

    According to the different treatment degree, the wastewater treatment system can be divided into primary treatment, secondary treatment and advanced treatment.
    The primary treatment only removes the suspended solids in the wastewater, mainly by physical methods, and the treated wastewater generally cannot meet the discharge standards.

    For the secondary processing system, the primary processing is pre-processing. The most commonly used secondary treatment is biological treatment, which can greatly remove colloidal and dissolved organic matter in wastewater, so that wastewater meets the discharge standards. However, after secondary treatment, there are still a certain amount of suspended matter, dissolved organic matter, dissolved inorganic matter, nitrogen and phosphorus and other algae proliferation nutrients, and contain viruses and bacteria.

    Therefore, it can not meet the requirements of higher discharge standards, such as treatment into the small flow, poor dilution capacity of the river may cause pollution, can not be directly used as tap water, industrial water and groundwater recharge source. Tertiary treatment is to further remove pollutants that cannot be removed by secondary treatment, such as phosphorus, nitrogen and organic pollutants, inorganic pollutants and pathogens that are difficult to degrade by biology. The tertiary treatment of wastewater is a "advanced treatment" method that further adopts chemical method (chemical oxidation, chemical precipitation, etc.) and physical and chemical method (adsorption, ion exchange, membrane separation technology, etc.) to remove some specific pollutants on the basis of secondary treatment. Obviously, tertiary treatment of wastewater is costly, but it can make full use of water resources.

    Sewage and industrial wastewater discharged to sewage treatment plants can be treated harmlessly using various separation and conversion technologies.


    Basic Principles

    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.

    Cleaning methods & common techniques

    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.16pd6

    Processing equipment

    Domestic sewage treatment system requires a variety of equipment, the following are commonly used treatment equipment:

    1. Grille: used to remove large particulate matter in wastewater, such as paper, cloth, etc.

    2. Sand sedimentation tank: used to remove sand and sand and other solid particles in wastewater.

    3. Sedimentation tank: used for primary treatment, the suspended solids and suspended sediments in wastewater are precipitated by gravity.

    4. Air flotation tank: used for primary treatment, the suspended matter in the wastewater floats up through the action of bubbles, and then it is removed by scraper.

    5. Filter: for primary treatment, through the filter medium to remove suspended solids and organic matter in wastewater

    6. Activated sludge reaction tank: used for intermediate treatment, by adding activated sludge and oxygen, so that microorganisms can decompress organic matter in wastewater.

    7. Anaerobic digester: used for intermediate treatment, through the action of microorganisms under anaerobic conditions, the organic matter in wastewater is converted into biogas.

    8. Biofilm reactor: used for intermediate treatment, the organic matter in wastewater is degraded through the action of biofilm.

    9. Deep filter: used for advanced treatment to remove trace organic substances from wastewater through filter media 10. Activated carbon adsorber: used for advanced treatment to remove organic matter from wastewater by the adsorption of activated carbon.

    11. Ozone oxidation reactor: for advanced treatment, through the oxidation of ozone to remove organic substances in wastewater.