[Case Study:Cloth Filter] Tianjin Haozhong Project

1. Working principle:

The Vertical Fiber Cloth Media Filter is mainly used for advanced treatment of wastewater and reuse of reclaimed water. The technology uses a fiber filter medium with the concept of "anti-particle size" in directional order and a washing device with special moving linear scanning. It has the advantages of low energy consumption, small footprint, lower tank, low civil construction cost, high capacity, good effluent quality and simple operation and maintenance.

The filter units are produced as standard modules, which are highly interchangeable, and convenient to meet the requirements of different water capacity.

Vertical fiber cloth media filter is designed to remove the suspended solids in the wastewater. The core component is the fiber cloth. Under the impact of pressure difference, the liquid passes through the fiber cloth and solid particles are trapped by the cloth, so that the separation of liquid and solid is achieved and SS concentration is reduced.

2. Structure：

The vertical fiber cloth media filter is mainly composed of filter unit system, base plate, automatic backwash system, filter tank, settled solids discharge tank and low voltage electric control cabinet.

3. Filter unit system:

The fiber cloth media filter is a vertical filtration system. 2 pieces of filter cloths are mounted on a frame. The width of frame is 96mm. The frames are installed on the base plate.

4. Base plate：

The base plate is the collection system of the filtered water. At the same time, it is also the mounting plate of filter unit system. After the water passes through the filter cloths, the filtered water flows to the discharge end of the filter.

5. Automatic backwash system：

Automatic backwash system includes the vehicle, back wash pump and back wash pipeline. During filtration, part of the suspended solids are adsorbed on the surface of the filter cloth, forming a sludge layer gradually. With the accumulation of sludge on the filter cloth, the filtration rate of filter cloths goes slower, and the water level of the filter tank gradually increases. When the water level reaches to the pre-set value, the back wash pump begins to work and clean the filter cloths.

6. Filter tank and sludge discharge tank：

Filter tank and sludge discharge tank are the overcurrent carrier of the whole filter. The filter body is used to collect backwash wastewater and sediment which flows to the wastewater collection network of the plants area through pipelines, then returns to the front processes.

7. External interface of the process：

The external interface of the system mainly has three parts: front water inlet connection, back water outlet connection and backwash wastewater discharging connection.

8. Electronic control system (filter system)：

•The electronic control system of the equipment is composed of local control cabinet, liquid level instruments, cables and bridges connected with the whole set of equipment.

•Electrical low pressure components (switch, contactor, thermal relay) use products of CHNT and Omron brand.

•It is equipped with a control system, which only provides feedback signals of equipment operation (dry contact signal) that can meet the operation needs of the equipment.

•The material of the local control cabinet is coated carbon steel and the protection grade is IP54.

9. Controlling principle:

The filter removes SS from the water through fiber cloth system. As the suspended solids gradually accumulate on the surface of the filter cloth, the pressure difference between the inside and outside of the filter frame increases, and the water level of the filter tank gradually rises. When the water level rises to the pre-set high level, the back washing pump automatically starts. At the same time, the travelling crane starts to move back and forth slowly, clean the cloth surface. After one cycle of back washing, the suspended solids on the surface of the filter cloth are discharged into the sludge drain tank by back washing pump. The pressure difference between the inside and outside the filter frame will return to the initial state, and the water level will drop until the next back washing process begins.

10. Control cabinet：

The local control cabinet has the following configuration:

•With fault detection function, it has start button, stop button. And it can stop automatically in any breakdown situation. 

•It has run and stop fault signal lights.

•It has local manual button, reset zero button (O) and emergency stop button for the entire functional control system.