The sludge centrifuge, with its efficient, automated, and compact design, has been widely used in the field of sewage treatment and has become the core equipment in the sludge dewatering process. Its working principle is based on the centrifugal force generated by high-speed rotation, which causes the solid particles in the sludge to be thrown towards the inner wall of the drum to form a solid ring layer, while the water is discharged through the weir in the liquid ring layer, achieving solid-liquid separation.
In the practical application of sewage treatment plants, sludge centrifuges have shown significant advantages. For example, the Jining sewage treatment plant adopts the German Fulewei horizontal spiral centrifuge (HST type) to dehydrate sludge with a solid content of 2.5% to 4.0% to 26% to 38%. The maximum processing capacity of a single equipment is 60m ³/h (with a solid content of ≤ 4% in the sludge), and the power consumption is controlled at 0.8~1.2kW/m ³ of sludge. This equipment operates in a fully enclosed manner, effectively avoiding secondary pollution caused by the open operation of traditional plate and frame filter presses. At the same time, it occupies only one-third of the latter's area, making it particularly suitable for factory areas with limited space.
In terms of technological optimization, sludge centrifuges are often linked with flocculant dosing systems. For example, sludge is transported to the centrifuge by a screw pump and mixed with PAM solution to form flocs, significantly improving dewatering efficiency. In addition, by adjusting the drum speed through a frequency converter (usually between 1000~3000 revolutions per minute), it can adapt to the dewatering needs of different sludge properties (such as primary sludge and mixed sludge).
In cold northern regions, low temperatures in winter can cause an increase in the viscosity of the medicinal solution, affecting the flocculation effect. A certain sewage treatment plant successfully controlled the fluctuation of mud cake solid content within 2%~3% by maintaining indoor temperature above 10 ℃ and using hot water to clean the interior of the equipment, ensuring stable operation throughout the year.
From an economic perspective, although the initial investment of sludge centrifuges is relatively high, their continuous operation and high degree of automation significantly reduce labor costs. Taking the Jining project as an example, a dual machine operation of 18 hours/day can process 2160m ³/d of sludge. Combined with the dewatered sludge transportation and separated water reuse system, the comprehensive operating cost is reduced by about 15% compared to traditional processes.