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Russian Application of Diaphragm Filter Press in Pesticide Production Wastewater Treatment
Pesticide wastewater is a highly polluted wastewater generated during the pesticide production process, mainly from the production, synthesis, refining, and packaging of pesticide raw materials. Pesticide wastewater has complex components and a high pollution load, making it difficult to treat. Therefore, in the treatment process, targeted process technologies must be adopted according to different pollution sources, such as physical and chemical treatment, biological treatment, membrane filtration technology, filter press filtration, etc., to effectively remove harmful substances in wastewater and meet environmental discharge requirements. This article will introduce the application of membrane filter press in treating pesticide production wastewater.
Main Characteristics of Pesticide Wastewater
High toxicity: Pesticide wastewater contains a large amount of pesticide residues. Many pesticide compounds are highly toxic and difficult to degrade. Long-term presence in water bodies may cause continuous pollution to the environment.
Complexity: Pesticide wastewater has complex components, including both difficult-to-degrade organic pollutants and inorganic substances, such as heavy metals, nitrogen and phosphorus compounds, etc. Its complexity increases the difficulty of treatment.
High pollution load: COD, BOD, SS, and other indicators are usually high, especially containing a large amount of organic matter, suspended matter, heavy metals, etc., and multi-stage treatment is required to meet the discharge standards.
Filter Press Application Process
Pretreatment: wastewater regulation and flocculation
Regulating wastewater pH: By adding acid or alkali to adjust the pH of wastewater, the effect of flocculants can be improved to ensure that solid matter can be better condensed.
Adding flocculants (PAM): The commonly used flocculant is polyacrylamide (PAM). After adding PAM, the suspended particles in the wastewater will quickly aggregate into agglomerates, making solid-liquid separation easier.
Initial filtration stage
The wastewater is pumped into the filter chamber of the membrane filter press, where the filter cloth intercepts the solid particles, and the liquid is discharged through the filter cloth. This step uses ordinary pressure filtration (primary filtration), where the solid particles and liquid are separated under a certain pressure to form a preliminary filter cake.
Diaphragm compressing stage
After the filter cake is formed, the diaphragm is expanded by gas or liquid (usually air or water) to squeeze the filter cake further. The residual water in the filter cake is squeezed out by the pressure of the diaphragm, and the moisture content of the filter cake is greatly reduced. This step can significantly reduce the volume of sludge and improve dehydration efficiency.
After compressing the diaphragm, the filtrate is discharged again and collected in the filtrate tank.
Unloading and processing filter cake
As the filtration process ends, the membrane filter press will automatically or manually discharge the filter cake, which falls off the filter cloth and becomes solid waste.
After filtration, the filter cake can be incinerated, landfilled, or recycled. For example, for pesticide sludge containing organic components, the deeply dehydrated filter cake can be mixed with other fuels in proportion and sent to the incinerator for incineration. The heat generated can be used for power generation or heating. The slag after incineration can also be used as a building material, such as an additive for cement.
Effect of Pesticide Wastewater Treatment
Leachate reduction prevents secondary pollution
If sludge or solid waste that has not been dehydrated by filter pressing is directly piled up, it may produce a large amount of leachate under rainfall or other environmental influences. These leachates may contain pesticide residues or other toxic substances, causing pollution to soil and water bodies. Through filter-pressing dehydration, the generation of leachate is effectively controlled, reducing potential harm to the environment.
Sludge reduction
The sludge treated by the filter press is solid, which significantly reduces the volume of the sludge. The reduced volume means that the space required for sludge storage is also greatly reduced, which significantly relieves the pressure on treatment facilities or landfills.
Sludge incineration
The sludge cake formed by filtration can be mixed with other fuels and used for incineration in an incinerator. During the incineration process, the organic matter in the sludge is burned and releases heat. The heat generated by incineration can be recovered through combined heat and power (CHP) technology and converted into electricity or used for heating.
Resource utilization of slag
The residue after incineration (i.e., slag) can be used in the production of building materials. The processed slag can be used as roadbed filling in road construction as a viable option to replace natural mineral materials.
Slag can also be used as an additive in the cement production process to improve the performance of cement and reduce the demand for other raw materials, thereby achieving the purpose of resource recycling.
Conclusion
As an important piece of equipment in the treatment of pesticide production wastewater, the membrane filter press has the characteristics of high efficiency, energy saving, and environmental protection. It can not only effectively improve the efficiency of wastewater treatment but also reduce operating costs and environmental risks. By optimizing equipment parameters and operating conditions, the membrane filter press can play a more important role in the treatment of pesticide production wastewater.
