Primary Study On Dewatering Device And Technology Of Municipal Sewage Sludge

The technology and device were primarily investigated to enhance the flocculating and dewatering effect of activated sludge. Based on the parameters and technology of the dewatering device of both Jiangning WWTP (waste water treatment plant) and Chendong WWTP for dewatering treatment of the secondary settler enriched sludge, the simulating device for dewatering in lab and its operating condition were achieved, and the operating parameters for dewatering were investigated. By means of the device and the operating conditions, the flocculating and dewatering abilities of laboratorial products PDA with cationic degree 10～40% and intrinsic viscosity 7.81～16.38 dL·g-1 to the two WWTP enriched sludges were investigated, in contrast with commercially available flocculants from Ciba company under the same condition.The result showed that PDA with 20% cationic degree and 10.56dL·g-1 intrinsic viscosity showed lower dewatering rate value with the dosage of 70 mg·L-1 under the simulated operating condition:400mL sludge for flocculation,200N low pressure for 100s and 1200N high pressure for 100s, the water-content of the filtered cake after dewatering could reach 69.13% for Jiangning WWTP sludge with lower water-content and biochemical index value, higher transmittance and surface relative hydrophobicity value. PDA with 30% cationic degree,10.38dL·g-1 intrinsic viscosity showed lower dewatering rate value with the dosage of 50 mg·L-1 under the simulated operating condition:400mL sludge for flocculation,200N low pressure for 270s and 1200N high pressure for 150s, the water-content of the filtered cake could reach 67.39% for Chendong WWTP sludge with higher water-content and biochemical index value, lower transmittance and surface relative hydrophobicity value. The turbidity, CODcr, total N, total P, NH3-N in the supernatant liquid of the sludge from the 2 WWTPs firstly increased, then decreased with the increasing of flocculant dosage under the experimental condition, the transmittance firstly decreased, then increased with the increasing of flocculant dosage. While the Zeta potential totally increased with the flocculant dosage.Therefore, by establishing the simulating device for dewatering, the filter-press dewatering simulation experiments could be conducted in lab and the correspondence of the flocculant properties and the sludge properties could be investigated.