| 摘要: | 本研究目的為利用小型回分式批次反應器(SBR)實廠與人工濕地系統，以操作不同參數試程，由進出流水濃度探討不同試程對SBR去除氮磷的影響，並由人工濕地各個不同處裡單元的水質變化，探討組合系統去除氮磷之效益，將來擴充到中型廠後續操作之參考。
SBR污水廠每日操作1個批次，每個批次8小時，本研究SBR污水處理廠共進行四個試程，每個試程均以改變反應期的操作程序進行試驗，第一個試程的反應期操作程序為好氧/缺氧，添加碳源，第二試程的反應期操作程序同第一試程，但不添加碳源，第三試程的反應期改採兩階段缺氧/好氧操作，並分成兩階段入流污水，第四試程的反應期改採三階段缺氧/好氧操作，分成三階段入流污水。SBR污水廠的放流水則排入後端之三級處理人工濕地，人工濕地的單元分別為草溝、密植式表面流動濕地、表面下流動人工濕地，濕地總面積為2476 m2。
研究結果顯示，SBR平均處理污水量為58 ± 9 m3/d，SBR單元試程一的進流水總氮平均濃度為28.5 ± 5.2 mg N/L，出流濃度為18.4 ± 1.2 mg N/L，去除率為35%，進流水總磷平均濃度為3.9 ± 0.8 mg P/L，出流濃度為3.5 ± 1.4 mg P/L，去除率為10 %。試程二的進流水總氮平均濃度為67.2 ± 39.2 mg N/L，出流濃度為47.8 ± 17.0 mg/L，去除率為18 %，進流水總磷平均濃度為5.1 ± 0.8 mg P/L，出流濃度為5.4 ± 1.6 mg P/L，試程二因無添加碳源，總氮去除效果不如試程一。試程三進流水總氮平均濃度為41.3 ± 27.5 mg N/L，出流濃度為35.1 ± 5.4 mg N/L，去除率為15 %，進流水總磷平均濃度為3.1 ± 0.7 mg P/L，出流濃度為4.0 ± 1.3 mg P/L。試程四進流水總氮平均濃度為42.1 ± 11.9 mg N/L，出流濃度為31.0 ± 4.4 mg N/L，去除率為27 %，進流水總磷平均濃度為4.5 ± 1.0 mg P/L，出流濃度為5.1 ± 1.2 mg P/L。試程三、四雖然改為多階段入流污水且改變反應期操作，但進流水BOD濃度低，仍無法有效促進脫硝作用，更無法營造有效生物除磷環境，導致SBR除磷效益不佳。人工濕地各單元氮磷去除效果，草溝濕地單元進流水總氮濃度為32.9 ± 16.3 mg N/L，出流水為5.4 ± 2.2 mg N/L，進流水總磷濃度為4.6 ± 1.6 mg P/L，出流水為3.3 ± 1.5 mg P/L。密植FWS濕地單元出流水總氮濃度為5.0 ± 3.2 mg N/L，出流水總磷濃度為1.6 ± 0.9 mg P/L，SSF濕地出流水總氮濃度為4.2 ± 3.5 mg N/L，出流水總磷濃度為0.8 ± 0.4 mg P/L。SBR結合人工濕地後，可以達到總氮小於15 mg N/L，總磷小於2 mg P/L的目標，也可符合水再生再利用規範。
Small-sizes of a full-scale sequential batch reactor (SBR) and a constructed wetland (CW) system were used to explore variations of nitrogen and phosphorus removal with both different operating modes of SBR and different wetland types (i.e., grass ditch wetland, densely planted free water surface (FWS) system wetland, and subsurface flow (SSF) system wetland). Achievements of the present study are anticipated to provide reference for the operation and management of the medium-size of full-scale SBRs.
The small-size SBR was operated for one batch daily with a cycle time of 8 h. In the present study, four different operating modes were carried out. The first operating mode was a combined oxic/anoxic (O/A) process with a supplement of carbon source (molasses). The second one was a combined OA process without a supplement of carbon source. The third one was a combined A/O/A/O process with two-step sewage- fed but without a supplement of carbon source. The fourth one was a combined A/O/A/O/A/O process with three-step sewage-fed but without a supplement of carbon source. The treated water of the SBR was discharged into the CW system with a total area of 2476 m2.
The average daily flow of SBR was 58 ? 9 m3/d, whereas the average flow rate of the CW system was 46 ? 11 m3/d. The results obtained from the first operating mode of the SBR showed that the average initial and final total nitrogen concentrations were 28.5 ? 5.2 and 18.4 ? 1.2 mg/L, respectively (i.e., 38% of total nitrogen removal); the average initial and final total phosphorus concentrations were 3.9 ? 0.8 and 3.5 ? 1.4 mg/L, respectively (i.e., 10% of total phosphorus removal). From the results of the second operating mode of the SBR, the average initial and final total nitrogen concentrations were 67.2 ? 39.2 and 47.8 ? 17.0 mg/L, respectively (i.e., 18% of total nitrogen removal); the initial and final average total phosphorus concentrations were 5.1 ? 0.8 and 5.4 ? 1.6 mg/L, respectively (i.e., insignificant removal of total phosphorus). The afore-said findings indicated that the performance of the first operating mode was superior to the second mode, mainly because the former was supplemented with required carbon source for proper denitrification. From the results of the third operating mode, the average initial and final total nitrogen concentrations were 41.3 ? 27.5 and 35.1 ? 5.4 mg/L, respectively (i.e., 15% of total nitrogen removal); the average initial and final total phosphorus concentrations were 3.1 ? 0.7 and 4.0 ? 1.3 mg P/L, respectively (i.e., insignificant removal of total phosphorus). From the results of the fourth operating mode, the average initial and final total nitrogen concentrations were 42.1 ? 11.9 and 31.0 ? 4.4 mg/L, respectively (i.e., 27% of total nitrogen removal); the average initial and final total phosphorus concentrations were 4.5 ? 1.0 and 5.1 ? 1.2 mg/L, respectively (i.e., insignificant removal of total phosphorus). The afore-said findings indicated that the performance of the third and fourth operating modes was apparently inferior to the first operating mode, mainly because insufficient initial carbon source (COD) was provided and inadequate anaerobic environment for phosphorus removal was maintained.
Moreover, the results obtained from the grass ditch wetland showed that the average total nitrogen concentrations in the influent and effluent were 32.9 ? 16.3 and 5.4 ? 2.2 mg/L, respectively; the average total phosphorus concentrations in the influent and effluent were 4.6 ? 1.6 and 3.3 ? 1.5 mg/L, respectively. From the results of the densely planted FWS system wetland, the average total nitrogen concentration and total phosphorus concentration in the effluent were 5.0 ? 3.2 and 1.6 ? 0.9 mg/L, respectively. From the results of SSF system wetland, the average total nitrogen concentration and total phosphorus concentration in the effluent were 4.2 ? 3.5 and 0.8 ? 0.4 mg/L, respectively. Accordingly, a combined SBR-CW system can be used for not only meeting the EPA effluent standards of total nitrogen and phosphorus (i.e., less than 15 and 2 mg/L, respectively), but also reaching to water reuse purposes. |
