Sludge Treatment Technology of Pig Farm Wastewater
The main waste water for raising pigs mainly comes from a series of waste water discharged during the raising process. The main characteristics of the waste water are as follows: The concentrations of suspended solids and organic pollutants are high, and a certain amount of hair and feces are discharged in the feeding process.
These contents of waste water are discharged directly, affecting the health of surrounding residents.
Sewage treatment process
The main process design is as follows:
Waste water will be collected and discharged into grit chamber after slag removal by grid(Johnson screen grid).
After the initial sedimentation, the wastewater flows into the regulating tank automatically, and the water quantity and quality are regulated by the regulating tank, and the wastewater is fully mixed.
The effluent from the regulating tank is lifted to the acidizing tank by the submersible sewage pump. Most of the organic pollutants are degraded and removed by acidification.
The acidification treatment effect of hydrolysis acidification tank is improved, and gap oxygenation equipment is set in hydrolysis acidification tank to avoid sludge sedimentation.
The effluent from hydrolysis acidification tank flows into biological contact oxidation tank for oxygenation.
The effluent from the biological contact oxidation tank is lifted into the air flotation tank and treated with physicochemical treatment after dosing and coagulation. The scum from the air flotation tank flows into the sludge concentration tank automatically. After the effluent of the air flotation tank reaches the discharge standard, it will enter the drainage well. The sludge concentration tank is provided with a collecting pipe to return to the regulating tank to avoid overflow of muddy water.
The sludge in the sludge concentration tank is dewatered by the sludge dehydrator, the waste water discharged from the dehydrator is returned to the regulating tank through the trench.
(We provide wedge wire drum screens for all brands of manure separators – screw press drum screen)
Sludge treatment process
Sludge is the product of sewage treatment process and an important part of the whole sewage treatment station. The purpose of treatment is to reduce the water content of sludge, reduce the volume of sludge, achieve the stability of properties, and create conditions for further treatment.
Overall process selection of sludge treatment
The general process of sludge treatment is: concentration → digestion → dehydration → drying → disposal
Considering that if digestion treatment is adopted, a series of structures and equipment such as digester, heating system, agitation, biogas treatment, etc. need to be added, with increased investment and poor economic benefit. Therefore, this design does not consider the digestion of sludge.
Selection of Sludge Dewatering Methods
- Vacuum filtration
The vacuum filter dehydrator can be continuously produced and automatically controlled, but it has many auxiliary equipment. The filter cloth needs regular backwash cleaning. The operation process is complex, and the filter cloth is easy to block. After dehydration, the sludge moisture content is high, which is generally only used for digestion sludge dehydration.
- Plate and frame filter pressing
The dewatering effect of plate and frame press filtration is good, the price is low, the moisture content of sludge after dewatering is low, the labor operation intensity is general, and the operation management and cost are moderate. In this process design, plate and frame filter pressing is adopted.
- Belt filter
Belt filter press is a widely used sewage dewatering equipment. The filter belt can rotate, operate continuously, and the sludge treatment effect is stable. However, the price of centrifugal dewatering is expensive, the motor power is high, and the operation cost is high. Only applicable to large-scale sewage treatment works.
- Sludge drying tank
Strictly speaking, the sludge drying pond should be called sludge filtration field. Because of the large amount of sludge produced by the sewage treatment station, the area of sludge drying pond needed is relatively large, the dehydration efficiency is relatively low, the sludge cleaning is not convenient, the moisture content of sludge is high, and the retained sludge without treatment will inevitably cause secondary pollution to the surrounding environment.