碩士 / 國立高雄海洋科技大學 / 海洋環境工程研究所 / 97 / This study carried out a small-scale field experiment on ecological sewage purification on a piece of flood land. It conducted a purifying treatment of domestic sewage in field as well as analysis and research in laboratory, using the “Cascade Sewage Ecological Distribution and Treatment System” by SHEN Jian-quan, an associate professor at the Department of Marine Environmental Engineering of National Kaohsiung Marine University. This system takes both overland flow and sub-layer flow into account, adopts several means including soil, microorganism, planting, and natural exposure, and turns each system into a series of terraces. Therefore, the study presents a multi-layer ecological engineering method based on terrace-style field. It is expected to use this system to improve the situation in which domestic sewage was emitted directly into the rivers, and to break people’s stereotype on flood lands of being messy and covered by weeds. Furthermore, this system can help us enhance the self-cleaning function of the rivers, create space for ecology, rest, and landscape, etc, and come up with solutions to the current lack of managerial staff as well as construction land for natural purification projects in Taiwan.
The study used the shoal of Ho-Jin Stream for the experiment. There were four experimental fields, including one ramp and three terraced fields, in which the third one was sheltered with waterproof cover. The total incoming sewage to each experimental field in each phase was all 6tons/day with soil depth 30cm and water supply 8hr/day. The experimental inflows include sewage drained from wastewater treatment plant of school in phase 1, sewage drained from wastewater treatment plant of school + original school sewage in phase 2, sewage drained from wastewater treatment plant of school + artificial sweet water in phase 3 and all original school sewage in phase 4 to increase the concentration. The alternative fields had ramp and terraced fields. There were three different plants sweet potato leaf, water spinach, pasture for cultivation, in which the field 4 was all pasture and field 3 was sheltered with waterproof cover.
According to the test results, the terraced field cultivating three plants with waterproof cover was the best when original school sewage with BOD concentration about 42ppm flowed three-layer fields in depth 4.5 meters each and hold in the surface layer about 54 minutes and 62 minutes in bottom layer. The TSS removal rate was 12.60 g/m2-day and treatment efficiency 77%; COD removal rate 29.46 g/m2-day and treatment efficiency 68%; BOD removal rate 7.69 g/m2-day and treatment efficiency 72%; TP removal rate 1.11 g/m2-day and treatment efficiency 57%.
For linear relationship among the fields, only group 4 was a field without waterproof cover cultivating single plant and had negative relationship with the R value of linear relationship between TP inflow concentration and removal rate in bottom layer. The remaining linear relationships were all good and positive.
In the system, the harvest period was around half year during 97/11~98/06. The price sold for each field is estimated $250,000 dollars per hectare each month based on the harvest benefit. In addition to simple cultivation (no water irrigation required) without insecticide, the cultivation method of this system may be applied to land similar to agricultural land (without waterproof cover).
This ecological sewage distribution and treatment system has the following advantages: 1. low cost of construction; 2. energy-free and pesticide-free; 3. combined with various ecological engineering methods, high treatment efficiency, and short hydraulic retention time; 4. producing edible crops, generating economic benefits, and attracting the locals to manage the system voluntarily; 5. easy to manage and maintain; 6. able to withstand flood.
| Identifer | oai:union.ndltd.org:TW/097NKIM8282003 |
| Date | January 2009 |
| Creators | kenwty, 王佳合 |
| Contributors | , 沈建全, 林瑩峯 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 150 |
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