常温下UASB处理鱼粉加工废水启动特性研究

Study on Characteristic of Fishmeal Wastewater Treatment by UASB Reactor under Normal Temperature

针对鱼粉加工废水经过混凝处理后仍含有较高浓度的COD(50g/L以上)、氨氮(4g/L以上)、盐分(5g/L以上)的问题,从有机负荷、进水和出水pH、挥发性脂肪酸、氨氮、盐分等方面,研究了常温下UASB的启动特性及其处理效果。结果表明,UASB反应器对鱼粉加工废水具有较好的处理效果,反应器内能形成大量的颗粒污泥,启动迅速、运行稳定,具有较强的酸、碱缓冲能力,未出现氨氮和脂肪酸的积累和抑制微生物活性的现象。当进水COD为15～20.5g/L、容积负荷为8～9kg/(m3.d)时,出水COD为2500mg/L(对COD的去除率>85%),产气量为0.46L/gCOD(CH4含量>80%,具有较高的利用价值)。颗粒污泥呈黑色椭圆状,粒径主要分布在0.315～3mm,污泥浓度为35g/L,MLVSS/MLSS为0.908,颗粒污泥的沉速为52.5～138m/h(沉降性能良好)。

The wastewater from fishmeal processing factories contains high levels of COD （ 〉 50 g/L）, NH3 -N （ 〉4 g/L） and salinity （ 〉5 g/L） even after coagulation. The performance of treatment by the UASB reactor under normal temperature was investigated, and the impacts of organic load, pH, VFA, NH3 - N and salinity were analyzed. The results show that the UASB reactor is capable of removing pollutants from the wastewater. The large amounts of granular sludge are formed in the reactor, the stable operation and strong buffering of acids and alkalis are achieved, and NH3 - N and VFA accumulation and inhibition do not occur during the running period. When the influent COD is 15 to 20.5 g/L and the loading rate is 8 to 9 kg/（ m^3 · d） , the effluent COD is 2 500 mg/L with removal rate of above 85%. Also, the biogas production is 0.46 L/gCOD, in which the content of CH4 is above 80%, having higher application value. The color of the formed granular sludge is black, its form is elliptical, and its grain size distribution is between 0. 315 mm and 3 mm. The sludge density is 35 g/L, the MLVSS/MLSS ratio is 0. 908, and the sludge settling rate is 52.5 to 138 m/h, with good settleability.