Study On Treatment Of High Concentration Latic Acid Distillation Residual Liquid By Internal Circulation Reactor

The L-lactic acid residue distillation of a bio-chemical company in Jiangxi province containing high concentration protein,starch,sugar and other organic matter. COD of this wastewater is about 6.0×10~5mg/L.Conventional biochemical technology is difficult to deal with it.This task based on the treatment of the L-lactic acid residue distillation in this company,and study on the treatment of IC reactor's effect and characteristics.The result shows:1,IC reactor can remove pollutants in the L-lactic acid distillation effectively and stabilize the effiuent's COD below 2000mg/L on the condition that diluting the COD of L-lactic acid distillation to average 10000mg/L,adjusting water pH value of 6.8 to 7.2,maintaining the temperature of influent 30℃.2,After the stable operation,technical parameters of IC reactor are:volume load: 9.4kgCOD/(m~3·d),HRT:21h,theory of gas production:37.5 m~3/h,circulation: 610m~3/h,COD and VFA of effluent average concentration:1883mg/L,5mmol/L;pH: 7.2～7.4;SS＜150mg/L.3,Separate domestication of sludge into "excited" and "strengthen" activity two phase.The phase of "excited" make the sludge has a COD removal rate of 10%of the original wastewater.The COD removal rate in "strengthen" phase rose to 50%.4,At the end of sludge domestication(60d),IC reactor sludge existed as floc mainly,but a small amount of granular sludge with the diameter of 0.5mm～1.0mm appears.Concentration of sludge at the bottom of reactor is 13.7g/L.After IC reactor operate 5 months,detected the sludge concentration of 4m,8m,12m,16m height reached 21.32g/L,13 g/L,4.03 g/L,1.21g/L.The sludge form is granular mainly,the largest diameter is 3mm.5,In the period of IC load operation,the initial volume load is 1 kgCOD/(m~3·d), increased 20%volume when the COD of effluent below 2000mg/L,VFA below 10mmol/L.In the prophase(1～11week) and anaphase(17～22week),the impact of load makes IC reactor has a great fluctuate of COD removal rate.But in the metaphase (12～16week) this fluctuate is less.Water pH value in the period of start maintains between 6.2 to 7.8.The load impact affects the VFA of effluent on the performance of in the former 11 weeks and the last 11 weeks fluctuates at the range of 7.2mmol/L～28mmol/L and 6.7 mmol/L～14.2mmol/L respectively.6,In the process of debugging though an additional impetus to increase the hydraulic load makes the COD removal rate rise average 30%.7,IC reactor can be used as the pre-treatment of L-lactic acid residue distillation. Following BAF process,can make the COD of final effluent below 80mg/L stably. Achieving the first-level effluent standard of《Integrated Wastewater Discharge Standard》GB8978-96.