At present, most rural sewage treatment equipment manufacturers in the market say that the equipment does not need to be dosed, but this situation mostly exists in the laboratory or under the condition that the water quality is very stable, and the actual application should be decided by comprehensively considering the discharge standard, treatment cost and treatment effect. Specifically, the first-class B standard of sewage treatment can meet the standard without adding chemicals, but it is more difficult to meet the standard without adding chemicals and films under higher discharge standards.
From the process point of view, rural sewage treatment equipment generally adopts biofilm treatment processes such as ao, a2o, mbr and sbr. This monkey process has a high removal rate of ss, cod and bod, but the removal rate of total nitrogen and total phosphorus is difficult to reach more than 70%. If the influent water quality is not ideal, measures such as chemical agents, electric phosphorus removal and wetland must be taken to make the total nitrogen and total phosphorus discharge up to the standard.
In addition, the imbalance of carbon-nitrogen ratio in rural domestic sewage is a common phenomenon. In order to create a good market environment for microorganisms and improve the treatment effect of integrated sewage treatment equipment. In operation and maintenance management, adding water quality blending agents such as glucose and ethanol to equipment is a common first paragraph. The sewage treatment standard requires that the sewage contains Escherichia coli, so it is necessary to add disinfectants such as calcium chloride. Simply pursuing MBR or combined process without adding chemicals will greatly increase the basic cost of equipment.
Therefore, the question of whether to add drugs to rural sewage treatment equipment cannot be generalized.