Sludge dewatering: efficient method + equipment recommendation    

 Key words: sludge dewatering machine, plate and frame filter press, centrifugal dewatering machine, sludge drying, sewage treatment plant  

    1. Why does sludge need to be dewatered?    

Sludge is a by-product of wastewater treatment plants and industrial wastewater treatment processes with a moisture content of up to 70% to 99%. If not dealt with in a timely manner, it will lead to the following problems:  

   Bulky: High moisture content increases transportation and disposal costs.  

   Secondary pollution: Sludge may contain harmful substances such as heavy metals and pathogens, which can easily pollute soil and water sources.  

   Waste of resources: Undewatered sludge is difficult to be recycled (such as incineration for power generation, brick making).  

 Solution: Efficient dewatering technologies (e.g. mechanical dewatering, chemical conditioning) to reduce the moisture content to 60% to 80% or even lower.  

    Second, the core method of sludge dewatering    

     1. Natural drying method    

   Principle: The use of solar and wind energy to evaporate water, suitable for areas with abundant land resources and dry climate.  

   Advantages: Low cost, no equipment investment.  

   Disadvantages: low efficiency, greatly affected by the weather, easy to produce peculiar smell.  

     2. Mechanical dehydration    

   Mainstream equipment :  

     Plate and Frame Filter Press: The sludge moisture is discharged through the filter cloth by applying pressure through a high-pressure pump.  

       Advantages: Low moisture content of mud cake (50% 60%), low price.  

       Disadvantages: easy to clog, need to be cleaned frequently, not suitable for oily sludge.  

     Centrifugal dehydrator: Centrifugal force is used to separate solids and liquids.  

       Advantages: Large processing capacity, continuous operation, suitable for sludge with high water content.  

       Disadvantages: high energy consumption, high noise, high equipment cost.  

     Belt Filter Press: Sludge is pressed through the filter belt to form an "S" shaped dewatering path.  

       Advantages: Simple operation, suitable for physical sludge.  

       Disadvantages: A large amount of rinsing water is required, which may cause secondary pollution.  

     3. Chemical conditioning    

   Principle: Add flocculants (such as PAM, polyaluminum chloride) or conditioners (such as lime, fly ash) to destroy the colloidal structure of sludge and release bound water.  

   Advantage: Improve dewatering efficiency and reduce subsequent energy consumption.  

     4. Emerging technology: sludge alkali stabilization    

   Principle: Add calcium oxide, magnesium salt and other alkaline substances to raise the pH value to more than 12, release free water and solidify heavy metals.  

   Advantages: no odor, no mud return, suitable for cement raw materials, soil conditioners and other resource utilization.  

    3. Recommendation of high-efficiency dehydration equipment    

     1. Plate and frame filter press    

   Applicable scenarios: small and medium-sized sewage treatment plants, inorganic sludge treatment.  

   Representative Model :  

     2. Centrifugal dehydrator    

   Applicable scenarios: large-scale sewage treatment plants, high moisture content sludge (such as residual activated sludge).  

   Advantages: High degree of automation and fast processing speed.  

     3. High Pressure Belt Filter Press (Secondary Dehydration Equipment)    

   Features: Combined with sludge modifier + high-pressure pressing technology, the moisture content can be reduced to less than 50%.  

   Advantages: Low energy consumption, mud biscuits can be incinerated for power generation or brick making.  

 Image suggestion :  

 Figure 1: Diagram of the working principle of the plate and frame filter press (showing the sludge pressing process of the filter plate).  

 Figure 2: Schematic diagram of sludge alkali stabilization process (additives→ pH increase→ dehydration solidification).  

    Fourth, the reference of successful cases    

     Case 1: Tianjin Ningchuang Sludge Reduction Project    

   Technical solution: The "sludge king" high-pressure laminated soft separator dewatering equipment is used to reduce the sludge with a moisture content of 80% to 50%.  

   Benefits: 60% reduction in transportation costs, sludge can be directly incinerated or landfilled.  

     Case 2: Zhongjia Sludge Drying Project (Zhongshan, Guangdong)    

   Technical solution: The heat pump heat source belt drying process reduces the moisture content of sludge from 80% to less than 40%.  

   Benefits: 50% reduction in volume, flexible for composting or incineration.  

    5. Summary of practical skills    

1. Pretreatment: Concentrate the sludge with high water content (such as gravity concentration and air flotation concentration).  

2. Chemical selection: Match the flocculant according to the sludge properties (organic/inorganic, particle size).  

3. Equipment maintenance: Clean the filter cloth regularly and check the centrifuge bearing to avoid clogging and wear.  

    6. Act now!    

If you need a customized sludge dewatering plan, click the button below to get a free consultation or equipment quote!