皂素生产废水的资源化综合利用实验

Feasibility study of alcohol production from saponin wastewater

皂素生产废水是强酸性高浓度有机废水,富含淀粉水解后的糖类。据此特点,以皂素生产中的一次废水为原料,经中和处理后进行酒精发酵,使废水资源化。结果表明,采用工业氨水为中和剂,中和用量为5.20%(体积分数),发酵接种量为10%(体积分数),总发酵时间为60h时,4L废水可生产出95%的工业酒精120mL。一次废水COD去除率达75%,后续废水量大大减少,具有明显的环境效益。经估算每生产1t工业酒精可处理41t一次废水,与生产成本相比,具有明显的经济效益。

A study was perform to determine the feasibility of producing alcohol from a saponin wastewater sample （pH d0.5, COD = 96 500 mg/L, BOD = 52 500 mg/L, reduced sugar = 7.02%） from amylum hydrolysis. The wastewater was first neutralized （to pH of 5.0） by ammonia, then inoculated with actively growing yeasts, and fermented for a total of 60 h at 30℃ ; the product was a solution containing 3.6% of alcohol. After multi-stage distil- lation to produce 95% alcohol, the final effluent （pH = 5.0, COD = 24 130 mg/L, reduced sugar = 0.4） containing a high concentration of ammonium salt was useful for making organic fertilizer. 120 mL of 95% alcohol and 8.7 g of dry yeast were produced from the 4 L wastewater sample, or 1 t of 95% alcohol from 41 t wastewater. The estimated cost, excluding the credit for the dry yeast by-product was ￥1 450/t of 95% alcohol produced, significantly lower than the price of ￥3 500/t for industrial grade alcohol. It is therefore feasible to produce alcohol from the saponin wastewater. A pilot scale demonstration will be performed to verify the cost estimate.