1, suitable for inlet type and concentration range.
Many buyers, project leaders or technicians ignore the applicable types and concentration ranges of integrated rural domestic sewage treatment equipment. The equipment manufactured by sewage treatment equipment manufacturers is aimed at low-concentration rural domestic sewage. Due to the differences of geographical environment and living habits in different regions of China, the concentration of rural domestic sewage varies greatly. Generally, the quality of domestic sewage in rural areas along the southeast coast is 200-400mg/L, NH3-N is 30-50mg/L, and SS is about 200 mg/L. The values of COD and BOD in the central and western regions, northern regions and areas that have completed toilet improvement will exceed 1-2 times. Once the water quality exceeds the standard, most rural sewage treatment equipment cannot discharge stably.
2. Equipment and materials
The material of integrated rural domestic sewage treatment equipment is closely related to cost, bearing capacity and service life. From the cost point of view, stainless steel >: FRP > carbon steel, service life: stainless steel > FRP > carbon steel, from the load point of view, stainless steel > carbon steel > FRP can be selected as needed.
3, sewage treatment discharge standard
Lower emission standards: secondary emission standards and tertiary emission standards; Conventional rural emission standards: national standard B, landmark B; Strict sewage discharge standards: national standard level A, sewage treatment plant landmark standard level A. It is necessary to make clear what level of discharge standard the water quality of the equipment needs to meet, otherwise it will affect the acceptance and delivery.
4, process technology
The equipment mostly adopts biological treatment technology, such as AO, A2O, SBR, MBR, biological oxidation contact and so on. AO, A2O and SBR technologies are mature and cost-effective, which are suitable for I B emission standards with low emission requirements. MBR and combined process are suitable for high-standard Grade A sewage treatment project, and the cost is generally high.
5, sewage treatment equipment processing load
Treatment load generally refers to the amount of sewage or total pollutants treated by sewage treatment equipment on the premise that the influent can reach the standard stably. The design standard of sewage treatment equipment is1100m3/day, the influent COD is 400mg/L, the influent exceeds 100m3/ day, or the total COD exceeds the equipment design standard. This means that the equipment runs at full capacity and the water quality will be greatly affected.