Soil Science Institute, National Agricultural Research Foundation, Thessaloniki, Greece.
Environ Technol. 2011 May-Jun;32(7-8):795-804. doi: 10.1080/09593330.2010.514009.
Environmental conditions and wastewater treatment performance in a full-scale duckweed pond system are presented. The treatment system consisted of three stabilization ponds in series and was fed with septage. Vacuum trucks pumped the septage from residential holding tanks and discharged it to the system daily. The inflow rates averaged 36 m3 d(-1) in the cold season and 60 m3 d(-1) in the warm season. Duckweed (Lemna minor) colonized the ponds in the warm months and survived during the cold season. Because of the difficult process for harvesting the duckweed biomass, the investigation of the treatment efficiency was carried out without plant harvesting. Samples were collected from the vacuum trucks and from the exit of each pond and were analysed for physicochemical and microbiological parameters over a period of 12 months. The results showed that the duckweed mat suppressed algal biomass, which in turn led to anoxic and neutral pond conditions. On an annual basis, the duckweed system sufficiently removed BOD5 (94%), NH4+ (72%) and E. coli (99.65%), with lower removal of TSS (63%) and Enterococci (91.76%). A slight increase (1.1%) was recorded for o-PO4(3-). Between the two sampling seasons, BOD5 and TSS removal efficiencies were higher in the cold season with the longer retention time. Similar removal values in the warm and the cold season were found for nutrients and bacteria. These findings indicate that BOD5 and TSS removals are less temperature-dependent at higher retention times, while ammonia nitrogen and bacterial removals are substantially influenced by temperature as well as retention time.
呈现了一个规模化浮萍池塘系统的环境条件和废水处理性能。该处理系统由三个串联稳定池塘组成，以粪肥污水为进水。真空卡车从住宅储水池中抽吸粪肥污水，并每天将其排入系统中。在寒冷季节，进水率平均为 36 m3 d(-1)，在温暖季节为 60 m3 d(-1)。温暖月份浮萍（Lemna minor）在池塘中定殖，并在寒冷季节存活。由于难以收获浮萍生物量，因此在不进行植物收获的情况下进行了处理效率的研究。在 12 个月的时间里，从真空卡车和每个池塘的出口处采集样本，并分析其理化和微生物参数。结果表明，浮萍垫抑制了藻类生物量，进而导致池塘处于缺氧和中性条件。浮萍系统在一年内充分去除了 BOD5（94%）、NH4+（72%）和大肠杆菌（99.65%），对 TSS（63%）和肠球菌（91.76%）的去除率较低。o-PO4(3-)略有增加（1.1%）。在两个采样季节之间，寒冷季节由于停留时间较长，BOD5 和 TSS 的去除效率更高。温暖季节和寒冷季节的养分和细菌去除值相似。这些发现表明，在较高停留时间下，BOD5 和 TSS 的去除较少受温度影响，而氨氮和细菌的去除受温度和停留时间的影响较大。
