地工不織布應用於呈層複合土壤水質淨化系統最適性之研究

A Study of Non-woven Geotextiles Application Optimal to MSL System

林孟儒(Meng-Ju Lin)

指導教授 ： 何嘉浚

國立臺北科技大學/工程學院/土木與防災研究所/碩士(2014年)

摘要

由於污水下水道及污水處理廠興建成本高且工期長，難以達到全面普及，故近年極度推行現地自然淨化系統(natural treatment system, NTS)，但NTS常遇到水力負荷率低、需要較大興建空間、對總磷去除成效不佳等問題，在寸土寸金的台灣也遇到瓶頸，於是引進呈層複合土壤水質淨化系統(multi-soil layering system ,MSL)。
本研究針對作為(soil mixture layer,SML)之包覆材料的地工不織布厚度對系統淨化成效之影響進行深入探討，地工不織布除了包覆濾材，更重要的是做為各種微生物菌滋長的介質。厚度較厚之地工不織布理論上能提供更多微生物生長空間，但厚度過厚影響施工性，或者生物膜過度累積反而易使系統發生阻塞問題。厚度過薄則會使微生物菌附著狀況不佳直接影響淨化成效，生物膜被水流沖出，造成水中有機質污染濃度上升，甚至大量生物膜堆積於出水口造成系統組塞。經過一系列之室內實驗後，發現2.75mm~3mm厚度之地工不織布最適合應用於MSL系統當中。
除此之外，研究不同厚度之包覆材料所適合之水力負荷率(hydraulic loading rate,HLR)也是本實驗重點之一，研究結果發現，HLR高低對於氨氮、COD、懸浮固體削減率影響有限，但在總磷削減率上可明顯看出差異，原因來自MSL系統除磷機制，須維持一定水力停留時間，確保化學反應完整，以達到最佳去除效果。

關鍵字

呈層複合土壤 ； 地工不織布 ； 現地處理 ； 水力負荷率

並列摘要

Due to the construction costs of sewerage systems are very expensive and long duration. It’s difficult to make popularly in Taiwan. Natural Treatment Systems(NTS) was thought that could replace the sewerage systems. However, NTS encountered great difficulties in practing at urbans. Needs huge construction areas, low Hydraulic Loading Rate(HLR), the reduction rate is very low for Total Phosphorus(TP) made people researching other way to treat domestic wastewater.
Multi-Soil Layering system(MSL) has higher HLR and smaller construction areas than NTS,and furthermore the reduction rate of TP approaches 90%. MSL been thought suitable for modern cities or urbans in Taiwan. Chang(2013) took geotextiles replaced the jute fabrics as the covering material of soil mixing block layer(SML) in MSL and extended the service life successfully.
The study focused that the influence of thickness of non-woven geotextiles on MSL purifying domestic wastewater. Non-woven geotextiles doesn’t only cover soil and other materials in SMB, but also plays an important role who reared microbial flora on surface. The thickness of non-woven geotextiles thicker could rear more microorganisms in theoretically. This study chose five kinds of geotextiles in different thickness and acted in MSL systems in laboratory. System A(1.5mm), system B(2mm), system C(2.6mm), system D(3mm), system E(4.5mm) performed two stages MSL system tests, respectively. First stage was cycling test that observed each system stabilizing situation in purpose. Second stage imitates the operation of real MSL systems in Japan that keep wastewater enter the system constantly. This study set three kind of HLR 1000, 2000, 3000, respectively. Found out the difference between all of systems and the influence of HLR on each systems in purpose.
Determined that the thickness of non-woven geotextiles between 2mm and 3mm suitable for MSL systems most as a result of tests. System A(1.5mm) couldn’t provide enough space to microorganisms growing leads to the reduction rate of COD and NH3-N lower than other systems obviously. System E(4.5mm) was clogged because of the thickness of non-woven geotextiles was too thick . Wastewater through SMLs hardly, in consequence, the reduction rate was lowest and the system clogged in six weeks.
Suggest that the HLR 1000 L/m2/day makes MSL systems removes TP well because lower HLR makes the mechanism of TP removing entirely. HLR between 1000 L/m2/day to 3000 L/m2/day doesn’t influence seriously other pollutants reduction rate as the result of this study.

並列關鍵字

Multi Soil Layering of System ； Woven Geotextile ； Natural Treatment System ； Hydraulic Load

參考文獻

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