Laboratory Expeirments Study On The Treatment For The High Concentration Starch Wastewater

The potato starch wastewater was imitated by the potato and water. And the flocculation,sedimentation and anaerobic granular sludge expanded bed (EGSB) on potato starchwastewater treatment and the influencing factors are studied by laboratory simulatedexperiments in this paper. The study provides a theoretical basis for flocculation-adsorption-EGSB processing on potato starch wastewater treatment by the laboratory test.Firstly, the flocculants were used to pre-treat the potato starch wastewater; the chilosanwas used as a coagulant in study. Influence of the type of flocculants, dosage of flocculant,pH values and dosage of coagulant to flocculation efficiency was studies, and the optimumflocculation conditions were determined．The results show that flocculant of PAC has a bettertreatment efficiency than BPFC and PAFC with COD removal rate of58.56%and BODremoval rate of42%, when the dosage of BPFC was4g/L, pH was6.5, dosage of coagulantwas1.5g/L. It makes the concentration of COD in potato starch wastewater has reduce from18000mg/L to7460mg/L, the concentration of BOD in potato starch wastewater has reducefrom5400mg/L to3130mg/L and it becomes easy to that follow-up treatment.Second, the influence of particle size of activated carbon, dozing quantity and pH value tothe organic removal rate in the potato starch wastewater treat. The result shows that theremoval rate of COD can reach49.3%and the removal rate of BOD can reach38%when theparticle size of activated carbon was0.125-0.25mm, the dosage was4.5g, the pH value was7.5, and the COD concentration could be decreased from7460mg/L to3780mg/L, the BODconcentration could be decreased from3130mg/L to1940mg/L.Finally, the EGSB reactor has been for two months and satisfied results have beenachieved on the treatment of high COD concentration organic wastewater. And the removalrate of COD could reach85%when the temperature was (30±1oC). The temperature and pHvalue all has an impact on the anaerobic digestion process,and the temperature has a greaterinfluence on the efficiency of COD removal in anaerobic digestion process.The greater thecooling rate, the greater the impact on COD removal rate, the activity of methanogenicbacteria recovery more difficult. Otherwise, there was a big impact on operating results. Ittakes a little effect for the running of EGSB reactor,when the pH value was5.5-7.Furthermore, the pH value of effluent can be maintained at above6.7,and the removal rate ofCOD could be reached to90%, the removal rate of BOD could be reached to93%.