Study On The Effect Of Chemical Conditioners On Dewatering Performance And Properties Of Sewage Sludge

The high moisture content has always been a bottleneck that hinders the sound disposal of sludge.The deep dewatering technology can reduce the moisture content of the sludge to less than 60%,and it also greatly facilitates subsequent disposal while realizing the reduction.The technology relies mainly on chemical conditioning and mechanical dewatering,where chemical conditioning improves sludge dewatering performance by adding chemical conditioning agents.The optimization of conditioners requires a comprehensive consideration of dehydration performance,economic costs,adaptation to final disposal methods,and feasibility.The development of high-performance conditioners is one of the keys to improving sludge dewatering performance.This paper studied the effect of chemical conditioners on sludge dewatering performance,revealed the mechanism of different kinds of chemical conditioners to improve sludge dewatering performance,and optimized the chemical conditioners with good dewatering effect,little effect on sludge properties,and favorable for subsequent final disposal.It provides development ideas for deep sludge dewatering technology and final sludge disposal.The specific resistance and moisture content of the dewatered sludge were used as evaluation indicators,the effects of different types of conditioners on the dewatering performance were studied:The optimum amount of flocculant in the single chemical conditioner was the least;and the coagulant had the best conditioning effect;The conditioning effect of the composite conditioner was generally better than that of the single type;?10%FeCl₃+16%CaO?could reduce SRF and moisture content of the sludge to 0.15×10⁹s²/g and 71.66%.The dewatering effect was greatly improved.Based on the analysis of the changes of the microscopic morphology,particle size,and flocculation properties of the Zeta potential during the conditioning process,the mechanism of action of the conditioning agent was analyzed:CTS accelerated the separation of sludge flocs and flocculated water;the average particle size of the original sludge is 45.97?m,the particle size of the flocculant increased the most after conditioning.The CTS increased the sludge particle size to 60.87?m,which was the maximum value;The particle size of the composite conditioner FeCl₃+CaO after conditioning was 28.58?m,which was the lowest value;The Zeta potential decreased mostly by FeCl₃,it decreased from-9.87mv to-4.32mv.The changes of sludge calorific value and physicochemical properties of the phase structure before and after conditioning were investigated:The heating value was inversely proportional to the dosage of the conditioning agent;and the addition of the compound conditioner did not affect the phase structure of the sludge.Finally,?10%Fe Cl₃+16%CaO?was selected as the optimal compound conditioner.the economic cost was 2.55 yuan per ton of sewage sluge.