| 摘要: | 本研究是針對國內第一座實場以社區生活廢水為處理對象的二行村人工濕地，探討人工溼地系統對汙染物去除效能之穩定性。系統自民國2002年6月開始操作至民國2005年10月為止，在4年的操作期間內，系統採樣與操作狀況大致上可分為三個階段：第一階段為系統操作初期，時間為2002年6月至2003年2月，系統平均污水處理量、水力負荷、水力停留時間分別為27.0±12.9 CMD、0.08m/d、6.8d；第二階段為系統增加穩定塘操作，時間為2003年3月至2004年3月，該階段平均污水處理量、水力負荷、水力停留時間分別為37.3±17.8 CMD、0.06m/d、15.1d；第三階段為系統穩定操作期，時間為2004年7月至2005年10月，系統平均污水處理量、水力負荷、水力停留時間改變為46.9±18.8 CMD、0.08m/d、12.0d。
針對污染物及營養原濃度變化，本研究以四季濃度平均的狀況探討，結果發現：生化需氧量(BOD)三階段系統平均進流濃度在25~60 mg/L之間，冬季系統進流濃度與去除率高，夏季則是進流濃度低與去除率較低的情況，但系統去除率大部分維持在60%以上；化學需氧量(COD)三階段系統平均進流濃度在80~110 mg/L之間，系統於冬、春兩季進流平均濃度、去除率較高，夏、秋兩季系統進流濃度低、去除率差，系統各季去除率大約維持在24%以上；總磷(TP)三階段系統平均進流濃度約在3.0 mg/L左右，系統於春、夏兩季進流平均濃度高，秋、冬兩季進流濃度低，系統去除率維持在25%以上，此可能由於進流TP濃度均不高，濃度變化無法維持平穩；而總氮與總凱氏氮三階段系統平均進流濃度分別約在17~23、16~22 mg/L之間，春季進流濃度高、秋季濃度低，系統總氮與總凱氏氮兩者之去除率分別約在25~85、20~80%之間，而系統硝酸鹽與亞硝酸鹽濃度則都低於1.0 mg/L以下，去除率也因為濃度低，濃度變化差異小，各季節之變化無法觀察統計出之規則性。
人工溼地經長期操作，本可因系統條件固定而穩定，然而由於氣候因素、進流水質變化及系統內植物成長差異，而使得系統操作在四年內的操作未能獲得一致性的結論。
The object of this study is to investigate the stability of operation for the Er-hang village constructed wetland, which is the first one to treat the domestic waste water came from the community in Taiwan. The discussion was based on the removing effect of the pollutants. The operation of the constructed wetland system started from November 2001, and stopped in October 2005. During the operation period of four years, there were three stages to divide by the operation condition and arrangement of system. The first stage, the initial period, was operated from June 2002 to February 2003, the average flow rate, the hydraulic loading, and the hydraulic retention time of system were 27.0±12.9 CMD, 0.08m/d, and 6.81d, respectively. The second stage, adding one pond before the system, was operated from March 2003 to March 2004, the average flow rate, the hydraulic loading, and the hydraulic retention time of system were 37.3±17.8 CMD, 0.06m/d, and 15.1d, respectively. The third stage was operated from July 2004 to October 2005, the average flow rate, the hydraulic loading, and the hydraulic retention time of system were 46.9±18.8 CMD, 0.08m/d, and 12.0d, respectively.
According to analysis for the season average concentration of pollutants in the systems, the results show that, the influent concentration of the biochemical oxygen demand (BOD) for three stages were between 25 and 60 mg/L. During this stage, the influent concentration and the removing rate were higher in winter, while they were lower in summer. However, the removing rates of the BOD always kept above 60%. The influent concentrations of the chemical oxygen demand (COD) for three stages were between 80 and 110 mg/L. During this stage, the influent concentration and the removing rate were higher in winter and spring, while they were lower in summer and fall. However, the removing rate of the COD only kept above 24%. The influent concentrations of the total phosphorus (TP) for three stages were about 3.0 mg/L, only. During this stage, the influent concentration was higher for both seasons of spring and summer, while it was lower in fall and winter. The removing rate of the TP always kept above 25%. The influent concentrations of total nitrogen(TN) and total kjeldahl nitrogen(TKN) for three stages were between 17~23 and 16~22 mg/L, respectively. The removing rates of the TN and TKN were between 25~85% and 20~80%. However, the nitrate and nitrite in the system usually were lower, below 1.0 mg/L. Then, their removing rates were not stable for all stages.
The stable operation of the constructed wetland will be present after operated for long time. However, it has past for four years, the stable state is not able to be gotten in the Er-hang village constructed wetland. It might be due to the factors of the weather, the quality of the influent water, and the growth of plants in the system. |
