Research On The Effect And Mechanism Of Teamwork Of Cationic Surfactants And FeCl₃and CaO On The Sludge Dewatering

With the widely-building of wastewater treatment plants, the yield of sewage sludgehas a enormous increase correspondingly. The high moisture content and the huge volumeare two important factors which has a great influence on the treatment of sewage sludge. Asa consequence, the dewatering become the key point to the subsequent disposal. At present,there need some pretreatment on the sewage sludge before the dewatering, such as physicaltreatment, chemical treament and biological treatment, to improve the dewaterability of thesewage sluge and enhance its effect. This thesis dose research on the effect of cationicsurfactants conditioning and the team work of cationic surfactants and FeCl3as well ascationic surfactants and CaO on the dewaterability of sewage sludge, and also themechanism of action has been studied. Main contents of this thesis are presented as follows:1. The screening of cationic surfactants and the effect and the mechanism ofcationic surfactants conditioning on the dewaterability of sewage sludgeDifferent cationic surfactants are screened using the index i.e., SRF, moisture contentin filter cake, water removal efficiency in the same time. The cationic surfactants are to beselected out to improve the dewaterability. It turns out that the cationic surfactants A and Bcan improve the dewaterability apparently. The effect of cationic surfactants conditioning onthe dewaterability of sewage sludge are investigated through the index which includes SRF,mositure water content in filter cake, water removal efficiency in the same time and thesettling ability.According to the turbidity of the filter liquid, the COD content, the protein content, thepolysaccharide content as well as the residual quantity of the cationic surfactants in filterliquid along with the analysis of microscopic image of the flocs, this part states theconditioning mechanism of cationic surfactants on the sewage sludge.2. The effect and the mechanism of the team work of cationic surfactants andFeCl3as well as the team work of cationic surfactants and CaO on thedewaterability of sewage sludgeThis part studies on the effect of the team work of cationic surfactants and FeCl3as wellas the team work of cationic surfactants and CaO on the dewaterability of sewage sludge.The reports shows that, the team work of the cationic surfactants and FeCl3and the teamwork of cationic surfactants and CaO has improved the dewaterability of the sewage sludgemore effectively than cationic surfactants alone did, and the condition in the sequence whichis the cationic surfactants is followed by FeCl3and CaO makes a better effect. In the experimental program, when the dosage of cationic surfactants is9g/100gDS and the dosageof FeCl3is5g/100gDS and the dosage of cationic surfactants is9g/100gDS and the dosageof CaO is15g/100gDS, the conditioning effect is the best.According to the turbidity of the filter liquid, the COD content, the protein content, thepolysaccharide content as well as the analysis of microscopic image of the flocs, this partstates the conditioning mechanism of the team work on the sewage sludge.