某石化企业长链二元酸生产废水的预处理工艺及现场应用

Industrial application and study for pretreatment of long chain dicarboxylic acid fermentation wastewater

某石油化工企业的发酵法长链二元酸生产装置会排放高浓度废水。废水中的二元酸盐及培养基成分使下游综合污水处理厂的进水总磷和有机负荷偏高,可能造成出水总磷严重超标的风险。通过实验优选出钙基预处理药剂并确定最优处理条件。即在pH为11、药剂投加量为3 g·L^(-1)的最优条件下,对总磷和COD的去除率分别达到97.9%和41.5%,且出水可生化性较好(BOD_(5)/COD约0.46),副产物绝干固渣产量仅有3.4 g·L^(-1)。以此为基础,开发了二元酸废水预处理工艺,并建成处理量6 t·h^(-1)的现场工程化装置。在长周期运行过程中,装置对总磷和COD的平均去除率为93.3%和53.0%。该工艺可有效保障了石化企业综合污水处理厂的总磷达标和稳定运行。

The wastewater discharged from the fermentation long-chain dicarboxylic acid unit of a petrochemical company greatly increased the total phosphorus(TP)and COD load of the downstream wastewater treatment plant(WWTP),and TP of the effluent was at a serious risk of exceeding the standard.In this study,calcium-based pretreatment agent was selected through experiments,and 97.9%of TP and 41.5%of COD can be removed at a laboratory scale.The production rate of dry residue is low(3.4 g·L^(-1))and treated wastewater kept good biodegradability(BOD_(5)/COD=0.46).Based on experimental results,the pretreatment processes for fermentation wastewater was designed and a 6 t·h^(-1) unit was built.During operation,TP and COD removal rates reached 93.3%and 53.0%,respectively.The efficiencies of the petrochemical WWTP are fully guaranteed.