小球藻生长及其净化猪场废水条件的优化

Optimization for Chlorella pyrenoidosa growth and purification of piggery sewage

为提高小球藻净化猪场废水的效果,在户外条件下系统比较了预处理方式、管道光反应器的种类和光径对蛋白核小球藻生长及其对猪场废水净化效果的影响。结果表明,猪场原废水COD、NH_4^+、PO_4^(3-)、TN、TP含量分别为710、491、54、590和108 mg·L^(-1)时,蛋白核小球藻对经过3级过滤预处理后的猪场废水净化效果最好,其中脱色率及NH_4^+去除率分别高达88.56%和83.48%,显著高于对原废水的处理效果(P<0.05)。在夏季户外条件下,用平铺管道反应器对蛋白核小球藻进行放大培养,发现小球藻能耐受夏季户外高温,生长良好,最终藻粉产量达到0.13 g·L^(-1)。采用直径为5 cm的立式光生物反应器培养蛋白核小球藻,通过循环采收,藻粉产量可达到0.93 g·L^(-1),其蛋白质含量最高达到58.9%,汞、砷、镉、铅含量分别小于0.1、1.0、0.5和4.0 mg·kg^(-1),符合《饲料用小球藻粉》(DB32/T 564-2010)标准。采收小球藻后的出水中,NH_4^+、PO_4^(3-)、色度的去除率均高达90%以上,基本达到国家排放要求。该研究结果可为制定猪场废水的净化及蛋白核小球藻的工业化生产方案提供参考。

The effects of pretreatment methods of piggery sewage, types and light path of piping photoreactorson the growth of Chlorella pyrenoidosa and purification of piggery sewage were systematically studied underoutdoor conditions. The results showed that when the COD, NH4+、PO43-, TN and TP of raw swine wastewater were710, 491, 54, 590 and 108 mg·L-1, respectively, Chlorella pyrenoidosa performed the best purification of thetertiary filtration pretreated wastewater, and the removal rates of colority and NH4+ reached 88.56% and 83.48%,respectively, which were significantly higher than those for the raw wastewater treatment(P<0.05). Underoutdoor conditions in summer, the scale up culture of Chlorella pyrenoidosa with plastic pipes indicated thatthese algae could withstand high temperature and grow well with a yield(dry weight) of 0.13 g · L-1. WhenChlorella pyrenoidosa was cultured in a vertical photobioreactor with a diameter of 5 cm, the yield(dry weight)was 0.93 g·L-1 and the highest protein content was 58.9% through recycling collection. The contents of mercury,arsenic, cadmium and lead in algal biomass were lower than 0.1, 1.0, 0.5 and 4.0 mg·kg-1, respectively, whichwas in accordance with the standard Chlorella Powder for Feed(DB32/T 564-2010). The removal rates of NH3-N、PO43-, and colority in effluent after harvesting Chlorella were all over 90%, which basically met the nationalemission standards. The results of this study can provide references for technology development of piggerysewage purification and industrial production of Chlorella pyrenoidosa.