Water contained in the sludge is divided into the interstitial water, capillary hydration water, the surface adsorbed water and internal water. The first is called "free water", the latter three are called "irreducible water", the four water??in addition to the interstitial water can press to remove physically, the other three water surface is wrapped with a strong negative electron, it can not remove by the physical pressure filtration. The interstitial water is accounting for 70% of the sludge water; capillary water capillary water is accounting for 20%; about 10% of particles adsorbed water and particle internal water, sludge dewatering object is the interstitial water.
Sludge dewatering depends on the sludge particle size, sludge specific resistance and organic content except with the form of existence of water in the sludge. The sludge particles are finer, the higher the organic content, and the greater the resistance, the greater the difficulty of dehydration is.
Sludge modifying use physical or chemical method to change the existence form of water in the sludge, changing the size and properties of sludge, so as to reduce the sludge specific resistance and improve the dewatering performance.
The moisture content of raw sludge can be reduced from 98%--99.5% to 95% by concentration, then put the sludge into sludge modification equipment. While add solid modified reagents in the equipment in proportion, making the reagent well contact with the sludge particlesthrough high-speed mixing. After mechanical wall-breaking effects by high shear emulsifying equipment, to make the intracellular fluid and adsorption water transfer to interstitial water, and ensure to improve sludge dewatering performance. Finally, the moisture content of sludge is less than 60% after dehydration with high pressure filter.
Process Flow Chart
This process could reduce the sludge moisture content from 99.5% to 60%, dropping 98.8% volume of the sludge, and decreasing transportation and final disposal cost greatly.
Simple process, and mature technology, keeping the final moisture content of the sludge below 60% stably;
No stench and pathogens, the sludge cake is hydrophobic, so it will not cause a second pollution in open-air stacking.
Less medicine usage, low energy consumption and high extent of automation, so it can shorten the sludge dewatering time, improve the dewatering effect and reduce labor intensity.
Modular equipment, integrating or spliting according to the site condition.
The complete sets of equipment take low land occupancy, good operating environment., domestic equipment,, easy to operate and maintain.
NO need for any fuel and no dependence on boundary conditions.
One of the sludge deep dewatering engineering in sewage treatment plant in Jiangsu Province
Construction Time: 2013
Type of the sludge: physic-chemical sludge and biochemical sludge
Main process: BSH-DeWa sludge drying and deep dewatering
Requirement: sludge moisture content &le 60%