The Experimental Study On Wood Cooking Wastewater Treatment

The source of the wood cooking wastewater,its characteristic and studies on treatment of the wood cooking wastewater and its treatment actuality were summarized through studying on wood cooking wastewater from wood company in Guangdong.By doing pilot studies,the affection on circulation parameter using acidification-coagulation-anaerobic-aerobic treatment was discussed.And each units' circulation effect, efficiency,infection factor and control conditions were researched systemic,in order to provide a feasibility project for the practicality treatment.The result of acidification was:in 10%vitriol,when pH was controlled at 3.0,it had the better removal of COD_Cr,lignin and SS.When the chemical coagulation treatment was used to deal with the wood cooking wastewater,FeCl₃,Al₂(SO₄)₃ and FeSO₄ were employed as coagulants,with PAM as coagulant aid.It was showed that molysite had the better removal efficiency than aluminates',and molysite.had the better removal efficiency than ferrite.Take into account from feasibility and treatment efficiency,the best coagulant optimized was FeCl₃,and the removal of lignin,COD_Cr and SS was 93.77%,76.5%and 98.01%respectively,when pH was 4 and the coagulant quantity was 500 mg/L.In anaerobic system,the hydraulic retain time(HRT),cubage load(Nv),temperature and pH were studied.It was showed that UASB have the strong resistance to impact load which was brought by concentration transformation.When HRT is 14h,COD_Cr removal can be at least 70%.When HRT was longer than 14h,COD_Cr removal hadn't been increased.Confirmed HRT was 14h,and cubage load was between 10.40～12.55kgCOD_<sub>Cr/m³Â·d,it had the good removal.Temperature and pH had little effect when they had little change.Aerobic treatment had high treatment efficiency and stabilization.When the aeration time was 8h,COD_Cr removal can be 90%,BOD₅ removal can be 95%.It was indicated that using acidification- coagulation-anaerobic-aerobic treatment was feasible in technically.The outlet COD_Cr＜200mg/L,BOD₅＜30mg/L,SS＜100mg/L,NH₄-N＜10mg/L,which hadn't achieve the first let standard of DB44/46-2001 in Guangdong.But it's good removal efficiency had the momentous significance for the further treatment to extend the let standard and reducing the treatment cost.Finally,decomposition mechanism of lignin was expatiated,outlet from each treatment step was analysed by infrared spectrum analysis method,which validated using acidification- coagulation-anaerobic-aerobic treatment had good removal efficiency on lignin.Above all,using this treatment method had a stabilization effection and provided a reference to the treatment of high concentration wood cooking wastewater.