Investigation Of Carrageenan Wastewater Treatment By Composite Flocculand

According to sources and characteristics of carrageenan wastewater (carrageenan press water and wash water),in view of the severe situation and carrageenan industry facing challenges.Understand the commonly treatment technique of industrial wastewater.On this basis,this thesis studied the treatment of squeezing water and water wash with chemical flocculation method.Thinking about the requirement of enterprise,choosing the simple and feasible method,treat the press wasrewater and washing water, in order to reuse the press water after treating, and improve the effluent quality of wash water.This thesis concluded the following contents and results:1. In the study of carrageenan press wastewater,we investigated the flocculation of lower molecule carrageenan in carrageenan press wastewater by inorganic flocculant or inorganic/ organic composite flocculants. In order to recycle the water sample that use in the subsequent water section. The effects of the dosages of PAC/PAM,different temperature and pH and setting time on the treatment efficiency are studied. Under the optimum experimental conditions of flocculation (dosage of PAC:2g/L,dosage of PAM:15mg/L,the temperature:25-40℃,pH 4-7,setting time 30min),more than 90.0% of lower molecule carrageenan was removed and Aluminum concentration value less than 0.2mg/L,which could satisfy the demands of the pre-treatment process for carrageenan press wastewater to be recycled into injecting well,that can to reduce the production costs.2. Because of the water wash complicating,high alkalinity,high chromaticity,high COD,high chlorine,it is difficult to treat the water wash.Comparing with the treatment flocculation of water wash after using ployaluminium(PAC),polymeric ferric sulfate(PAFS),polymeric ferric(PFS),AlCl3 and chiyosan(CTS),five kind of coagulants,four kind of ployacrylamide.it was determined that PAC,PFS and CTS were chosen to be coagulant and anionic ployacrylamide with molecular weight of to be helping coagulant.Before the experiment,it must be neutralized by acid,due to the high alkalinity of wash water.Experiments to COD and color removal percentage.The effects of dosage of flocculant,dosage of coagulant and pH.The experimental results show that the coagulation is better than flocculation to the effects of treatment.It can also be concluded from the result of the experiment,The treatment higher COD and chromaticity of the wash water:PAC3.5g/L,PFS5.25g/L,PAM0.15 g/L,to be processed water pH is about 6,the COD and chroma being removed better.That is to say COD removal rate was 73.7%,chroma removal rate is 72.8%;For the higher COD and lower chroma,using composite flocculant CTS/PAC/PAM,the COD and chroma being removed better.The situation that CTS 0.1g/L,PAC 3.5g/L,PAM 0.2g/L,pH adjusting to about 7,is the better treatment.Under the condition,COD removal rate was 54.2%,and chroma removal rate was73.7%.From what has been discussed above,PAC/PAM were the better coagulation to treat press wate.It achived better treatment and met requirements of the enterprise.Chosen the appropriate flocculating to deal with water wash,and improve water quality.