The use and characteristics of active sand filter

With the enhancement of domestic environmental protection awareness, the drainage standards of sewage treatment plants have been raised to higher standards. It is necessary to deeply remove SS, TP, and N in the tail water. Active sand filters are more widely used in advanced sewage treatment. .

The test proves that the active sand filter has a good removal effect on SS and TP machine nitrate nitrogen in water. It can be widely used in the treatment of municipal sewage, industrial sewage, rainwater reuse and other sewage. The active sand filter is based on the counter-current principle. The raw water to be treated enters the sand filter through the water distributor located at the bottom of the filter through the water inlet pipe.

The water flow counter-circulates the filter bed from bottom to top, and the filtered filtrate gathers on the top of the filter and flows out through the overflow. In this process, the SS and TP in the sewage are intercepted by the sand bed of the active sand filter. The filter material intercepting the dirt at the bottom of the sand filter is lifted to the sand washer at the top of the filter by an air lift pump, and the pollutants are separated from the filter material by turbulence. The impurities are discharged through the flushing water outlet, and the clean sand is returned by its own weight. The sand bed thus realizes continuous filtration. The sand washing wastewater is discharged through a special pipe.

The active sand filter has high efficiency and can work continuously for 24 hours. It does not need to be shut down and backwashed, and does not need backwashing valves and backup filters, reducing operating costs. The active sand filter has no rotating parts other than the quartz sand filter material during operation, so the failure rate is low and the maintenance cost is low.

Because the single-stage filter material is used and the filter material is cleaned in time, the active sand filter has a small head loss, about 0.5m; it can withstand the 150mg/L concentration of SS inlet water quality for a long time while the outlet water quality remains unchanged; the filter material is cleaned in time and can be Ensure high-quality and stable water output without periodic water quality fluctuations.