真實垃圾與灰燼共同厭氧消化之研究

Anaerobic Co-digestion of Real MSW and MSWI Ashes

林松輝(Sung-Hui Lin)

指導教授 ： 羅煌木

朝陽科技大學/理工學院/環境工程與管理系/碩士(2009年)

摘要

隨著工商業發展及國民生活水準與消費的提升，所產生的廢棄物也隨之增加。因土地不易取得，我國垃圾處理已由掩埋方式逐漸採以焚化為主之中長期垃圾處理方向。但垃圾焚化後灰燼仍約佔原體積之百分之十五。焚化後灰燼處理仍將成為主要環保問題之一。本研究進行焚化爐底灰與飛灰之特性分析及其與真實垃圾（市政固體廢棄物生活垃圾）共同厭氧消化研究探討。垃圾焚化後，灰燼仍需處理，以灰燼為營養源添加於垃圾和汙泥的混合物可加速垃圾分解，進而加速厭氧消化、加速產氣，產出的甲烷和氫氣可回收作為燃料，並將剩餘有機垃圾充分利用。為模擬實際掩埋狀況 (垃圾與覆土比4:1)，使用30公分高、底部邊長15公分的四角透明柱體容器作為管柱，將實驗設定的五個條件物(底灰、飛灰、土壤、底灰+土壤、飛灰+土壤)加上2個空白組，共22組。將不同添加比例之底灰、飛灰、土壤和真實垃圾依上述步驟混合，觀察此5個條件物與真實垃圾共同厭氧消化的情形。將這22個管柱厭氧生物反應槽置於35℃之溫控箱中，以觀察垃圾分解之情形。每天記錄每個反應槽之產氣量(運用排水集氣法)，每週取出80mL滲出液過濾後，分析其pH、氧化還原電位(ORP)、導電度(EC)、鹽度(SAL)；每月並分析TS、VS，採集滲出液，檢測COD、金屬含量等。試圖找出灰燼添加作為垃圾覆土掩埋，促進掩埋場垃圾之快速分解、產氣與生物穩定性更為精確的數據，亦即找出真實垃圾添加灰燼後，在法規範圍內之重金屬溶出量和回收氣體最大量雙重條件下，灰燼（底灰、飛灰）添加最適比例和的最適量的樣本。由實驗得到以下結果：（一）添加飛灰40g/L、飛灰60g/L、土壤1500g/L於真實垃圾，氣體產率均優於控制組，有利於垃圾快速分解、厭氧消化穩定進行及甲烷回收之正面效益。（二）飛灰40g/L和60g/L添加組的產氣量分別為30和43公升皆優於控制組的23公升和底灰組，在灰燼添加組的比較上，飛灰組在金屬溶出方面較底灰組為高，推估飛灰組較多的金屬溶出對於產氣有正面的助益。同時也證明適當比例灰燼添加做為掩埋場覆土有正面潛在之效益。（三）土壤1500g/L添加組為本次實驗累加產氣最多的樣本，各項參數的結果皆有利產氣進行，可見真實垃圾在適當的土壤環境下，可促進生物穩定性，使垃圾快速分解，產氣正常穩定的進行。

關鍵字

掩埋場 ； 底灰 ； 飛灰 ； 厭氧消化 ； 真實垃圾 ； 市政固體廢棄物 ； 甲烷 ； 重金屬

並列摘要

Sustainable development has been the core concept in the agenda of earth summit in Rio de Janeiro, Brazil in 1992. The core values have been used as the principal guidelines to resolve environmental and climate change problems at the moment in 21th century. Taiwan is a small island comprised of 26.36% plain and higher than two thirds of hill and mountain. Due to the enhancement of living standard and consumption, municipal solid waste (MSW) has increased and MSW incinerator (MSWI) has been the primary treat method for the MSW. However, the residues generated from the incineration still account for 15% of original MSW volume. They need to be treated carefully to prevent the secondary pollution. MSWI bottom ash (MSW BA) and fly ash (MSW FA) have been used as aggregate, soil amendment, back fill and co-composting. In this study, MSWI bottom ash and fly ash were co-digested with MSW to investigate their possibility as landfill cover. Anaerobic bioreactors of 30 cm height with 15 cm * 15 cm bottom area were used to simulate the landfill sites. One liter of real MSW was placed on the bottom of the anaerobic reactors. Then, 0.6 liter of anaerobic sludge seeding was placed on it. Then, the designated MSWI BA, MSW FA and soil were placed on the anaerobic sludge seeding. This arrangement accounted for one layer and four layer of placement were used to conduct the experiment. The total 22 anaerobic bioreactors were placed on the oven maintained at 35℃. Gas production was recorded by water replacement daily. pH, ORP, EC, Sal were measured after 80 ml of leachate taken and filtration weekly. TS, VS, and COD and metals in leachate were measured monthly. Through gas production and anaerobic parameters, the suitable ratios of MSWI BA and FA with MSW co-digestion can be obtained. Results showed that gas production was found to be beneficial in soil 1500 g l-1, MSWI FA 60 g l-1, MSWI FA 40 g l-1, control, and MSWI BA 600 g l-1 bioreactors. The gas production was found to be in the order of soil 1500 g l-1 > MSWI FA 60 g l-1 > MSWI FA 40 g l-1 > control ≧ MSWI BA 600 g l-1. Other anaerobic bioreactors were found to be strongly inhibitory in the MSW digestion. pHs in the range of 6-8 were found to be suitable for MSW anaerobic digestion. Released metals in suitable range were thought to enhance the gas production. However, exact beneficial levels may need to be tested for clarity in the future work by individual metal or mixed metals added on the designated MSW anaerobic digestion.

並列關鍵字

Metals ； MSW ； MSWI FA ； Landfill ； MSWI BA

參考文獻

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