Residential wastewater comes from the daily activities of people, mainly from residential buildings and public buildings, such as residences, offices, schools, hospitals, shops, restrooms, etc. The pollutants contained in which are mostly organics including protein, carbohydrates and fat as well as numerous pathogenic microorganisms such as bacteria and viruses. The organics present in residential wastewater are extremely unstable, not suitable for reuse, and can be extremely foul smelling. The bacteria and pathogenic microorganisms in residential wastewater feed on the organic matter in wastewater and multiply, which can cause infectious diseases to spread, so it’s of great importance to treat residential wastewater before it can be put back into the water supply.

Apart from residential sewage, hospital sewage, especially that from contagious wards, also contains chemical substances, radioactive wastewater and pathogens, so it must be disinfected before draining. The sources and the components of the hospital sewage are sophisticated. Such sewage contains deleterious pathogenic microorganisms, poisonous chemical substances and radioactive pollutants, with hazardous characteristics such as acute contagion and latency contagion. Unless it’s effectively treated, it will seriously pollute the environment and lead to a new way of spreading disease.

The pollutants in the slaughterhouse wastewater are mainly coming from blood, fat, animal hair, undigested food, feces, etc. The main pollutant in slaughterhouse wastewater is organics. Firstly by using a dissolved air flotation machine to remove the large amount of suspended matter and then by package sewage treatment plant to remove BOD5, COD and NH3-N from the water, we can finally create an organic fertilizer after dehydrating the sludge from the previous steps by using a volute screw press.

With grass stalks and wood pulp as raw materials, the procedure of pulping and papermaking includes pulping, washing, bleaching and papermaking. Alkaline pulping, semi-chemical pulping and mechanical pulping are current methods used for pulping in the paper mill industry. Depending on different methods, ingredients, yields, paper varieties and chemical recovery, the pollutants in paper mill wastewater differ greatly, but basically include a number of suspended solids, BOD5, COD and some poisonous chemicals.

The quality and yield of electroplating wastewater is related to the processing conditions, production load, operation management, water use methods and other factors. The components of electroplating wastewater are complicated and uncontrollable as it may include metal irons, cyanide and some highly toxic substances that can cause cancer and gene mutation.

One of the features of the textile dyeing industry is using large quantities of water and releasing large amounts of pollutants. Processes such as dyeing are the main cause of pollution in the textile industry, in which a number of water, chemicals and dyes are used for producing textile products. The textile dyeing wastewater mainly contains pollutants such as toxic organics, dyes, suspended substances, BOD5 and COD.