都市生活污水污泥再利用於土壤可行性之研究

Feasibility Study of Municipal Sewage Sludge Use in Soil

鄭宗杰(Tsung-chieh Cheng)

指導教授 ： 程淑芬 ； 張迪惠

朝陽科技大學/理工學院/環境工程與管理系/碩士(2012年)

摘要

隨著都市公共下水道普及率增加，污泥的產量逐漸增加，如何妥善的處置污泥是即將面臨的環境問題。生活污水污泥含有豐富的肥力成份，土地再利用是目前許多先進國家處置污泥的趨勢。污泥中存在相當量的重金屬，當再利用於土壤時之風險是本研究探討的主題。本研究採集台中市生活污水處理廠污泥，分析污泥重金屬含量以及重金屬鍵結型態，並以不同比例添加污泥於土壤中，透過植物栽種試驗了解污泥對植物生長及植體重金屬含量之影響。研究結果顯示污泥中Cu、 Zn及Cd之含量皆超過國內食用作物農地土壤管制標準; Cu在污泥中以有機物鍵結型態含量最多; Zn則以鐵錳氧化物鍵結型態; Cd則以殘留態。從植物栽種結果顯示，隨著栽種時間污泥對植物生長抑制及重金屬含量之情形逐漸浮現，其影響亦隨污泥添加比例增加。
經由鹽酸及檸檬酸清洗效率顯示，1M鹽酸去除重金屬總量比1M檸檬酸較佳，以去除鎘、鉛、鋅、鎳為主。雖然檸檬酸清洗對於重金屬去除效率不佳，但在各種重金屬的鍵結型態有很大的轉變，其中以可交換態及碳酸鹽態最為顯著，導致在這兩態中之去除效率而呈現負值現象。清洗效率呈現負值之現象，另一種原因本研究初步認為應該是萃取液含有其他型態萃取出之重金屬，經震盪清洗時間增加而再次吸附於污泥中而造成此現象。

關鍵字

生物有效性 ； 重金屬 ； 污泥

並列摘要

With the increase in urban public sewer penetration, sludge production has gradually increased, thus, how to properly dispose the sludge is an environmental problem to be address. Sewage sludge contains rich fertility ingredients, and land reuse of sludge disposal is a trend in many advanced countries. However, the sludge also contains a large amount of heavy metals, thus the risk of heavy metals in the sludge reused in land is the focus of this study. This study collected sludge samples from a sewage treatment plant in Taichung City to analyze heavy metal content of sludge and heavy metal bonding types. After adding the sludge in soil in different proportions, this study explored the impact of sludge on plant growth and plant heavy metal content through plant cultivation tests. According to the research results, the Cu, Zn and Cd contents of the sludge are more than the food crop agricultural land soil control standards in Taiwan. The content of Cu in the sludge is mainly in the form of organic boding; the content of Zn is mainly in the form of iron and manganese oxides bonding type; the Cd content is mainly in the form of residuals. The plant cultivation results suggested that the impact of sludge on plant growth suppression and plant heavy metal content gradually emerges over cultivation time, and the impact increases in tandem with the increase in proportions of sludge addition.
The cleaning efficiency of hydrochloric acid and citric acid suggested that, 1M hydrochloric acid is better than 1M citric acid to remove heavy metals, mainly including cadmium, lead, zinc, and nickel. Although heavy metal removal efficiency of citric acid cleaning is poor, it can significantly change the boding patterns of various heavy metals. Moreover, the removal efficiency in case of the exchangeable and carbonate patterns is negative. Another possible reason for the negative removal efficiency is that the extract contains heavy metals from other patterns which are adsorbed in the sludge with rising vibration cleaning time.

並列關鍵字

sludge ； heavy metal ； bioavailability

參考文獻

5. 行政院環境保護署，「安全飲用水安全手冊」(2010)。

11. 胡紹華、王世忠、何志軒、陳素華，「都會下水污泥環境特性與資源化的回顧」，資源與環境學術研討會，花蓮 (2007)。

10. 林怡雅，「探討生物聚醣三仙膠在生物吸附程序之應用」，碩士學位論文，中原大學化學工程研究所，桃園 (2005)。

17. 鄭長和，「污泥土地施用指標污染物的篩選與風險評估」，碩士學位論文，國立屏東科技大學環境工程與科學研究所，屏東 (2004)。

18. 簡豪挺，「污泥中重金屬結合型態對化學萃取重金屬效率之影響」，碩士學位論文，國立成功大學，台南 (2002)。