Municipal Sewage Treatment Knowledge

1. Characteristics of municipal sewage treatment

Municipal sewage treatment generally refers to municipal sewage treatment plants, river sewage treatment, large public institution sewage plants, etc. The sewage is characterized by large changes in water quality, high COD (chemical oxygen demand) and SS (suspended solids concentration), making it difficult to treat. Sewage treatment processes generally include primary sedimentation tanks, grit chambers, secondary sedimentation tanks, biochemical tanks (good maintenance, anaerobic tanks), sludge thickening tanks, sludge dehydration filter presses, etc. Due to the high concentration of organic matter, microorganisms, etc. in the sewage before treatment, any product designed to treat reclaimed water must be able to tolerate this variability and contain high concentrations of organic matter and living organisms.

2. Chemicals selected for municipal sewage treatment

In municipal sewage treatment, polyacrylamide flocculants are usually used, generally cationic polyacrylamide, and the effect is better when the ion degree is between 40-50. Sometimes, anionic polyacrylamide is used in primary or secondary sedimentation tanks to accelerate the settlement of suspended solids; while sludge dewatering filter presses are mostly belt filter presses, and generally use medium-strong cationic Polyacrylamide flocculant with a molecular weight of 9 million to 12 million and a concentration of 1‰-2‰.

Cationic polyacrylamide is a new type, high-quality, high-efficiency polymer. It is easy to dissolve in water, has fast settling speed, good water purification effect, does not contain harmful substances such as aluminum, chlorine and heavy metal ions, and has no water phase transfer of iron ions. It is non-toxic, harmless, safe and reliable. Cationic polyacrylamide flocculant can effectively purify municipal sewage, such as turbidity removal, decolorization, deoiling, dehydration, sterilization, deodorization, algae removal, removal of COD, BOD and heavy metal ions in water, etc. Due to the high content of organic matter in municipal sewage, cationic type is generally used. After use, the PH value and total alkalinity of the raw water change little, and the corrosiveness to the treatment equipment is also small; generally, the PH value of the water body is 4.0-11.0, and the PH value achieved by the effect is 6.0-9.0.

3. Dosage of municipal sewage treatment chemicals

When cationic polyacrylamide is used to treat municipal sewage, a very low dosage can achieve good results, and the cost is low, and the cost of its treatment can be reduced by 20%-50%. The dosage of the specific agent depends on the nature of the raw water, and the dosage is different in different situations. To calculate a more accurate dosage, it is necessary to conduct a beaker experiment based on on-site water samples to obtain the use conditions and dosage. Because the water quality of municipal sewage varies greatly, sometimes one or two kinds of agents are used in combination, which depends on the actual situation to determine the use of agents. In general, cationic polyacrylamide is selected for treatment.

The above is a brief introduction for municipal sewage treatment. How to choose a more suitable flocculant depends on the on-site water quality, process, and sludge dewatering equipment. The water quality can be tested in the laboratory; the process and sludge dehydration equipment can be tested on the machine.

ROSUN is a professional disinfectant products manufacturer in China. We produces different types of wastewater treatment products. If you are looking for a suitable products for municipal sewage treatment, welcome to contact us. ROSUN can provide you with the most suitable and effective products.