National Institute of Water and Atmospheric Research Ltd (NIWA), P. O. Box 11-115, Hamilton, New Zealand.
Water Sci Technol. 2011;63(10):2403-10. doi: 10.2166/wst.2011.200.
Wastewater treatment High Rate Algal Ponds with CO2 addition could provide cost-effective and efficient tertiary-level wastewater treatment with the co-benefit of algal biomass production for biofuel use. Wastewater grown algal biomass can have a lipid content of 10-30% of dry weight, which could be used to make biodiesel. This research investigated algal biomass and total lipid production by two pilot-scale wastewater treatment HRAP(S) (4-day HRT) with and without CO2 addition under New Zealand mid summer (Nov-Jan) conditions. The influence of CO2 addition on wastewater treatment performance was also determined. CO2 was added to one of the HRAPs (the HRAP(E)) by maintaining the maximum pH of the pond below 8. Measurements of HRAP influent and effluent water qualities, total lipid content and algal biomass production were made twice a week over the experimental period. Both HRAP(S) achieved high levels of organic compound and nutrient removal, with >85% SBOD5, >92 NH4(+)-N and >70% DRP removal. Algal/bacterial biomass production in the HRAP(E) (15.2 g/m2/d) was improved by CO2 addition by approximately 30% compared with that of the control HRAP(W) (10.6 g/m2/d). Total lipid content of the biomass grown on both HRAP(S) was slightly reduced (from 25% to 20%) with CO2 addition and the maximum total lipid content of approximately 40% was observed in the HRAP(W) when low NH4(+)-N concentration (<0.5 mg/L) and high maximum pH (>10.0) occurred. Total lipid content of the biomass increased by approximately 15% under nitrogen limiting conditions, however, overall algal/bacterial biomass production was reduced by half during the period of nitrogen limitation. More research is required to maintain algal production under near nitrogen-limiting conditions.
污水高级处理 高负荷藻类塘（HRAP）添加 CO2 可提供具有成本效益且高效的三级废水处理，同时还可生产藻类生物质以用于生物燃料。污水中生长的藻类生物质的干重脂质含量可达到 10-30%，可用于生产生物柴油。本研究调查了在新西兰夏季中期（11 月至 1 月）条件下，有无 CO2 添加的两个中试规模污水 HRAP（4 天水力停留时间（HRT））的藻类生物质和总脂质生产情况，并确定了 CO2 添加对废水处理性能的影响。通过将池塘的最大 pH 值保持在 8 以下，向一个 HRAP（HRAP(E)）中添加 CO2。在实验期间，每两周测量一次 HRAP 进水和出水水质、总脂质含量和藻类生物质产量。两个 HRAP（S）均实现了高有机物和营养物去除，SBOD5 去除率>85%，NH4(+)-N 去除率>92%，DRP 去除率>70%。与对照 HRAP（W）（10.6 g/m2/d）相比，CO2 添加使 HRAP(E)中的藻类/细菌生物质产量（15.2 g/m2/d）提高了约 30%。在 CO2 添加条件下，两种 HRAP（S）上生长的生物质的总脂质含量略有降低（从 25%降至 20%），当 NH4(+)-N 浓度较低（<0.5 mg/L）和最大 pH 值较高（>10.0）时，HRAP(W) 中观察到最大总脂质含量约为 40%。在氮限制条件下，生物质的总脂质含量增加了约 15%，但在氮限制期间，藻类/细菌生物质的总产量减少了一半。需要进一步研究以在接近氮限制的条件下维持藻类的生产。
