Flowing sand filter

Overview of Flow Sand Filter Products:

Integrating flocculation, clarification, filtration, and biological treatment functions, it simplifies the traditional process flow, has relaxed requirements for the inlet water quality, can withstand SS concentration ≤ 150mg/l inlet water, continuous filtration, high efficiency, no need for shutdown backwashing, no initial filtrate problem, double-layer sand washing, doubling the cleaning effect. The conical design at the top of the water distributor ensures that there are no blind spots for sand flow.

WORLDS continuous flow sand filter is a continuous operation treatment equipment that integrates flocculation, clarification, filtration, and biological treatment functions. It is widely used in the fields of drinking water, industrial water, sewage deep treatment, and reclaimed water reuse treatment. The continuous flow sand filter (also known as the active sand filter) adopts the principle of upflow fluidized bed filtration and a single homogeneous filter material. The filtration and sand washing are carried out simultaneously, and it can operate continuously for 24 hours without stopping for backwashing. The clever sand lifting and washing structure replaces the traditional high-power backwashing system, with extremely low energy consumption, no maintenance required, easy management, and unmanned operation.

Application scope of flow sand filter:

1. Suitable for purifying slightly polluted water, it can treat surface water and water with low water quality requirements (such as cooling water)

2. Suitable for the deep treatment of industrial water and wastewater, as well as the reuse of reclaimed water, it can be set up in conventional activated sludge processes such as AO, A2O, SBR systems, etc CASS、 The backend of oxidation ditch and other systems.

Main functions: Remove total suspended particulate matter, remove ammonia nitrogen, and add chemicals to remove total phosphorus

Working principle: The continuous flow sand filter adopts the reverse flow principle.

1. The water to be treated flows into the inlet distribution pipe ① at the bottom of the equipment, flows upward through the filter bed and is filtered, and then flows out from the filtrate outlet ② at the top.

2. The filter sand containing impurities is lifted from the conical bottom ③ of the equipment by the pump ④ to the sand cleaner ⑤ at the top.

3. The cleaning of sand begins in the pump, and impurities are separated from the sand particles under turbulent mixing. Dirty sand overflows from the outlet of the pump and enters the winding path of the cleaner ⑥, where the sand is washed clean by a small flow of clean water in reverse flow. Impurities are discharged through the sand washing water outlet ⑦, and the cleaned sand particles (heavier) return to the sand bed ⑧.

4. The result is that the sand bed continuously undergoes slow sinking motion in the equipment. Compressed air for the pump is provided through the control panel.

The purification of water and the cleaning of sand are carried out simultaneously, so the filter can be continuously operated without interference.

Characteristics of Flowing Sand Filter:

1. The inlet water quality requirements are relaxed and can withstand inlet water with SS concentration ≤ 150mg/l;

2. Small footprint, integrating flocculation, sedimentation, and filtration treatment, simplifying the traditional process flow;

3. Low one-time investment, no need for separate facilities such as coagulation tanks and clarification tanks, no need for backwashing pumps and blowers, electric and pneumatic valves and other equipment;

4. High efficiency, continuous filtration, no need to stop and backwash, no initial filtrate problem;

5. Deep filtration, with a bed depth of 2000mm, has good filtration effect and stable effluent quality;

6. The head loss of the filter bed is small, about 1m;

7. Easy to renovate and expand, modular structure can flexibly increase or decrease the number of filters according to changes in water volume;

8. The use of special biological filter media, carbon sources, and chemical agents can achieve excellent nitrogen and phosphorus removal effects

Unique advantages of continuous flow sand filter:

1. The unique design of the maze type sand washing device completely isolates the cleaning water area from the clean water area, eliminating secondary pollution of the clean water area by the cleaning water. The double-layer sand washer design doubles the cleaning effect, and the turbulence effect doubles under the same stroke. The cleaning water discharge rate is low, generally 3% to 5%, and there is no loss of filter material.

2. The water distributor adopts a comprehensive design of amplitude and circular water distribution, with uniform water distribution and a conical design at the top of the distributor to avoid dead corners. The filter material utilization rate is high, and the head loss is small, which can avoid short circuits in upward water flow.

Typical process flow:

Continuous flow sand filters can be used for direct contact filtration of surface water and groundwater in tap water, thereby eliminating the need for coagulation tanks in traditional three-stage treatment processes; In conventional secondary biochemical treatment, the continuous flow sand filter can be directly installed after the secondary sedimentation tank to deeply treat the effluent of the secondary sedimentation tank, without the need for specialized process facilities such as coagulation tanks and clarification tanks. Coagulant can be directly added to the inlet pipeline or channel, and the circulating movement of the filter material inside the filter can play a stirring role. Compared with conventional three-stage filtration, the continuous flow sand filter process significantly reduces the engineering quantity and investment, has low operation and maintenance costs, and avoids the disadvantages of the traditional three-stage treatment process, such as numerous facilities, complex processes, high investment and operating costs.

Installation form of flow sand filter:

1. Independent installation filter type

It consists of internal components of the filtration tank, including water supply pipes, water supply distributors, air lift pumps, and sand washing devices. The filter tank is connected to the inlet water, filtrate, and cleaning water through flanges. The main part of the filter is made of stainless steel or fiberglass. Other options are provided according to specific needs. The filtering equipment can operate with a single filter or multiple filters in parallel to meet the filtering requirements.

2. Installation as a filtering component

High power continuous flow sand filtration equipment is usually composed of filtration components and built in cement tanks. The filtering component consists of a stainless steel or fiberglass conical bottom and internal components. The choice between a cement tank or a standalone filtration method is more economical depending on the actual filtration scheme and specific conditions. When installing this type of filter, all filter units (each consisting of multiple filter components) share a sand bed. A set of equipment essentially has no filtering area limitation, so continuous flow sand filters can be applied to large water plants and sewage treatment plants that treat water equivalent to 100000 or more people.