曾文水庫淤泥於綠屋頂建築材料之應用研究

Abstract

近年來台灣水庫皆面臨嚴重淤積問題，因而水庫淤泥去化與再利用之議題即受到極大之關注。因此，本研究期以水庫淤泥搭配特定比例之水泥、中和劑、保水劑及有機質，製成綠屋頂之植生基材，並將綠屋頂模組化後，降低傳統綠屋頂施工之複雜性及提高民眾之架設意願。 本研究所採用之淤泥係採自曾文水庫。其後，根據曾文水庫之淤泥特性進行不同配比之生長介質試拌，共計完成兩階段共計48組試體的施作與評估分析。依據其表面抗壓強度及植物生長情形等結果顯示，7號配比(淤泥1、水泥0.08、有機肥料0.6、中和劑0.06、保水劑0.05、水0.591，單位kg)為最適用配比。 以7號配比為基礎，製作完成綠屋頂模擬試驗模組，並進行觀測，其結果顯示具有一定之降溫與逕流消減功效。另以人工降雨試驗進行抗沖蝕能力之結果顯示，7號配比的沖蝕量僅為未加水泥對照組的8~17%左右。顯示本研究藉由前述生長介質開發試驗所採用之第7配比，確實具有顯著之抗沖蝕能力，可進而減少土壤肥力散失與環境污染之風險。除此之外，依據效益評估之結果顯示，利用淤泥進行綠屋頂之設置，對於民眾而言，建置綠屋頂的最大經濟效益為每平方公尺至少可節省19.7元/年；對於政府而言，淤泥去化的效益為每平方公尺166元；另包括減碳、淨化空氣及保水等，每年亦有約每平方公尺3.3元的效益。 綜合上述成果，顯示本研究所開發之綠屋頂模組，已達一定程度的效益，應可提供未來水庫淤泥去化及資源再利用之可行方案。

Taiwan has been facing a serious problem in reservoir siltation. Thus, removal and re-use of the deposited clay in reservoir is becoming more significant. Therefore, the main purpose of this study is to develop a method to produce plant growing substrate for green roof using the deposited clay in reservoir with a certain ratio of cement, neutralizer, water retention agent and organic fertilizer. Aside from this, in this study, green roof is modularized to make the construction of green roof simpler, so that the developed method is more likely to be accepted by people. The deposited clay used in this study was collected from Zengwen Reservoir. After considering the properties of the deposited clay, different agents such as neutralizer, water retention agent, organic fertilizer and cement, were added with different ratios (mix formula) for trial mixing tests. Trial mixing tests were conducted in two stages, and 48 sets of test in total were completed. From the results of surficial soil strength and plant growth, it was found Formula No.7 was the best, and its formula was: deposited clay 1, neutralizer 0.08, water retention agent 0.05, organic fertilizer 0.6, and cement 0.08. Samples were manufactured using Formula No.7 for demonstration and test. From the test results, it was found, the modules provided the beneficial effects for lowering the temperature and reducing the runoff. Besides, erosion tests were also conducted using the samples and the rainfall simulator in National Taiwan University. The erosion rates of the samples of Formula No.7 was as low as 8~17% of those without using any agent. The test results also showed the samples mixed using Formula No.7 could conserve the soil fertility and reduce the risk of environmental pollution. From the effect analysis, regarding the construction of green roof, the beneficial effect for the people was 169.3 NT dollars/years ; the beneficial effect for the government was 169.3 NT dollars/m2., and there was also about 3.3 NT dollars/m2 per year from the benefits of the carbon reduction, air cleaning and water retention. It might be concluded that the development of green roof modules in this study has demonstrated certain benefits and it is expected feasible to be used for removal and re-use of the deposited clay in reservoir.