- 學位論文
乾旱地區以碎石過濾系統處理灰水再利用於灌溉之評估
Evaluation of Recycling Greywater Treated by Granular Filtration System in Arid Areas for Use in Irrigation
摘要
污水和灰水回收再利用在全球範的圍內是水資源開發組合中一個新興的戰略課題。灰水包括生活污水中除去糞便以外的量體，灰水的重要面向包括它的特性、處理技術、再利用方式，與它再利用時產生的相關環境影響。尋找適當的灰水處理的方法仍然是個挑戰，因為選擇所依據於幾個變因，如灰水的品質和數量、氣候條件、處理成本、操作條件，與預期再利用標的所相關聯的品質要求。在缺水的乾旱或半乾旱國家如約旦，這一挑戰尤其嚴峻。 本論文的第一個目標是開發、安裝與驗證一個高效、簡便且經濟實惠的分散式灰水處理系統，可適用於乾旱和半乾旱地區的農村住戶以灌溉農園為目的使用。其次目標是檢討通過處理後灰水灌溉對土壤電導度（EC）和土壤品質的影響，經兩年使用後調查，評估灰水回收再利用的可持續性。此外，亦訪查灰水再利用戶使用後的認知與態度，並歸納他們的使用經驗。 本論文對灰水的特性和各種灰水處理技術進行了回顧。這種分析有助於對現場灰水處理系統的設計參數篩選。因此，進行現場研究測試，以收集有關人工濕地的處理效率，並確定最適用於乾旱條件下地區的設計參數（即：介質尺寸，床的尺寸，和植生型式）。這項研究的結果表明，無植生的碎石過濾床的性能比在同樣條件下的其他人工濕地組合更好。利用這些結果，進行了另一項研究，集中在一系列碎石過濾系統（GFS）的設計和處理效率評價。試驗使用的碎石過濾系統主要由三個處理階段組成：前處理（即：沉澱和篩除），主要處理（即：碎石過濾床（FB）），和後處理（如：過濾），並選用了兩種不同的在地材料介質即火山凝灰岩礫和礫石進行了測試。 試驗共構建了十五場處的碎石過濾系統（GFS）和連續兩年的操作監測。每個碎石過濾系統（GFS）提供約旦農村住家一個單一的灰水處理和再利用於農園灌溉系統。為了評價碎石過濾系統（GFS）的處理效率，對進水和出水水質進行監測比較。此外亦對使用兩年灌溉的農園場地其前後的土壤化學特性進行了比較。另外，也設計了結構化問卷收集用戶數據，調查使用者的經驗。 所有的碎石過濾系統（GFS）不論是使用凝灰岩礫或礫石介質皆能充分處理灰水，因為它們能有效去除原水中所含的有機污染物。使用火山凝灰岩礫介質的系統較使用礫石介質的系統更為有效，但其出水含有較高的陰離子和陽離子濃度。儘管其水質符合約旦灌溉用水的標準限值，但還需要進一步研究，以提升系統的處理效率。研究亦顯示使用碎石過濾系統（GFS）處理的灰水回收灌溉於農園經兩年後，所監測的關鍵土壤性質參數皆沒有任何明顯的不利影響。監測所有住戶場地的平均數據顯示，在土壤中的電導度（EC）顯著降低，平均值由灌溉前為0.97 dS/m 下降到0.41 dS/m。所有的用戶皆注意到他們農園的生產率獲得改善，以及約半數住戶注意到他們淡水的消耗減少。
並列摘要
Wastewater and greywater recycling is an emerging strategy being implemented worldwide to supplement water resource portfolios. Greywater comprises domestic wastewater flows, excluding toilet water. Important aspects of greywater include its characteristics, treatment, reuses, and the environmental impacts associated with its recycled. Finding appropriate greywater treatment methods remains a challenge, since the selection depends on several variables such as greywater quality and quantity, climatic conditions, cost, operating conditions, and the quality requirements associated with the intended use of the treated. This challenge is exacerbated in water scarce, arid or semi-arid countries, such as Jordan. The first goal of this thesis is to develop, install, and validate an efficient, simple, and affordable decentralized greywater treatment method that can be adapted for use by households in arid and semi-arid rural communities for the purpose of restricted agricultural irrigation (grow crops that are not eaten raw by human). Whereas, the second target is to investigate the sustainability of greywater recycling by focusing on the impact of treated greywater irrigation on soil electrical conductivity (EC) and soil quality, after two years of regular use. In addition, it examines perceptions and attitudes of the greywater users, and evaluates their experience practicing greywater treatment and reuse. A review of greywater characteristics and various greywater treatment technologies was conducted. This analysis informed the selection of a constructed wetland treatment system as the suggested on-site greywater treatment system. Therefore, a field study was conducted to collect data about the efficiency of this constructed wetland and to identify the design parameters (i.e., media size, bed dimensions, and plantation types) most suited to arid conditions. The results of this study suggested that non-vegetative beds (granular filter) perform better than the other constructed wetland combinations under these conditions. Using these results, another field study was conducted that focused on the design of a proper granular filtration system (GFS) and evaluated its efficiency as a decentralized greywater treatment system. Our GFS was composed of three treatment stages: pre-treatment (i.e., sedimentation and screening), main treatment (i.e., granular media filtration bed (FB)), and post-treatment (i.e., filtration). Two different local media were tested as FB medium (i.e., volcanic tuff and the gravel). Fifteen GFS were constructed and monitored for two years. Each GFS served a single rural Jordanian home by treating their greywater and recycling it for home garden irrigation. In order to evaluate the efficiency of GFS in greywater treatment, six GFS’s influent and effluent water qualities were monitored. Soil chemical characteristics before and after two years of treated greywater irrigation were compared. In addition, a structured questionnaire was used to collect data from all GFS users about their greywater experience. Our GFSs (using either volcanic tuff or gravel media) adequately treated greywater, as they removed the studied organic contaminants from raw greywater. A GFS that uses volcanic tuff media was more efficient in treating organic contaminants than one that uses gravel media, however, its effluent held a concentration of anions and cations. Despite the quality of GFS effluents was within the permissible limits for restricted irrigation set by the Jordanian standard, further studies are needed to increase the efficiency of the system. Moreover, irrigation using GFSs treated greywater did not have any apparent adverse effects on key soil properties at the studied sites after two years. The average data of all locations monitored showed significant reductions in soil (EC) (the average soil EC before greywater irrigation was 0.97 dS/m and decreased to 0.41 dS/m). All GFS users noticed improvements in their home garden productivity, and about half noticed a reduction in their fresh water consumption.
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