利用市政污水厂尾水培养产油微藻——营养盐去除与生物质生产

将1株产油淡水微藻——微拟球藻(Nannochloropsis sp.MASCC 11)分别接种到青岛市2家市政污水处理厂(STP)的尾水中,根据其生长、油脂产率和营养盐去除情况,评价了利用STP尾水培养微藻以生产富油的藻生物质同时深度净化尾水的可行性。结果表明,团岛污水处理厂(TD-STP)和李村河污水处理厂(LC-STP)尾水中无机氮和磷酸盐的浓度虽然远低于BG11培养基,但仍能支持微藻生长,而且以未经稀释的尾水更具优势,培养8 d后,藻生物量分别达到BG11培养基中生长微藻的65.23%和44.77%。STP尾水经稀释后处于营养盐缺乏状态,有利于藻细胞内脂质积累,但是油脂产率最大值(10.5 mg·L^-1·d^-1)仍出现在未经稀释的TD-STP尾水中,为未稀释LC-STP尾水的1.37倍。LC-STP尾水中微藻的油脂产率较低,可能与该处理厂接纳工业废水而在尾水中残留较多有害物质有关。在微藻的直接和间接作用下,TD-STP和LC-STP尾水中磷酸盐的去除率分别达到94.5%和100%;无机氮的去除率较低(分别为59.2%和45.4%),与尾水中初始N/P较高有关。上述结果表明,与接纳工业废水的污水厂相比,处理生活污水的污水厂所排尾水较适于培养产油微藻,能够实现产油微藻低耗培养与尾水深度净化相耦合。

Cultivation of An Oil-Producing Microalga in Effluents from Municipal Sewage Treatment Plants:Nutrient Removal and Biomass Production

An oil-producing freshwater microalga,Nannochloropsis sp.MASCC 11 was inoculated into the effluents discharged from the two municipal sewage plants(STPs)in Qingdao city.According to algal growth,lipid production and nutrient removal,the feasibility of culturing microalgae with STP effluent for producing oil rich algal biomass and the advanced treatment of effluent was evaluated.The results showed that although the concentrations of inorganic nitrogen and phosphate in the effluents of TD-STP and LC-STP were much lower than those in BG11 medium,they could support the growth of microalgae.The microalga had a growth advantage in undiluted effluents with a biomass concentration accounting for 65.23%and 44.77%of those in BG11 medium,respectively,after 8 days of batch culturing.The diluted STP effluent was in the state of nutrient deficiency,which was conducive to the accumulation of lipid in algae cells,but the maximum lipid productivity appeared in the undiluted TD-STP effluent(10.5 mg·L^-1·d^-1),1.37 times of that in the undiluted LC-STP effluent.The lower lipid productivity in LC-STP effluent might be related to the remaining harmful substances due to industrial wastewater treatment.Under the direct and indirect action of microalgae,phosphate in TD-STP and LC-STP effluents was reduced by 94.5%and 100%,respectively,whilst the removal rate of inorganic nitrogen is relatively low(59.2%and 45.4%,respectively),which may be related to the lower initial N/P in both effluents.The effluents from sewage plants receiving domestic sewage is more suitable for cultivation of oil-producing microalga,which can realize the combination of low consumption cultivation of oil-producing microalga and deep purification of effluents.