有機廢棄物厭氧消化固、液副產物資源化再利用研究

Anaerobic digestion of organic wastes for solid and liquid by-products recovery

蘇景明(Su-Jing Ming)

指導教授 ： 郭文健

國立屏東科技大學/工學院/環境工程與科學系所/碩士(2012年)

https://doi.org/10.6346/NPUST.2012.00210

摘要

為了瞭解厭氧消化系統放大為模廠規模的效果，以廚餘為單一進料基質在3,000L酸化槽及12,000L醱酵槽進行兩相式半連續式高溫厭氧試驗，進行此系統性能與產氣量之探討並徹底資源化利用液相及固相二相副產品。操作條件為以300㎏廚餘加水稀釋至600L/d作為進料量並將進料濃度定為90g COD/L-d而體積負荷（VLR）則為4.5kg COD/ m3-day，而醱酵槽的水力停留時間（HRT）為20天。
廚餘基本特性，經分析廚餘TCOD平均濃度高達134.6g/L，屬於高濃度有機廢棄物，其TS(%(w/w))約為19.8%，但絕大部分為揮發性固體物，VS(%TS)約佔93.7%，此顯示廚餘有機物質來源相當充足；而TCOD/TKN為48.83，TCOD/TP為215.4，如果以厭氧微生物所需之營養鹽COD：N：P ＝ 400：7：1來看，顯示廚餘中N、P營養鹽似乎仍有剩餘的現象。
在厭氧消化系統中在SS及TCOD去除率方面分別為86.9±3.41%及77.3±3.73%。產氣量約為6.95±2.63(m3/day)，而沼氣中甲烷及二氧化碳濃度百分比分別為65.76±3.60%及28.34±3.77%，甲烷百分比與文獻所提尚為吻合。
在副產物資源化利用部分，由水生植物水芙蓉及布袋蓮世代時間及植體吸收狀況中顯示，以添加不同比例液肥進行試驗比較，在試驗一、二、三之水芙蓉世代時間分別為7.875天、5.33天、5.68天，布袋蓮其世代時間分別為10.19天、6.86天、7.62天。而試驗一、二、三之水芙蓉濕重收穫量分別為485.71g/m2-d、914.29g/m2-d、828.57g/m2-d，布袋蓮濕重收穫量分別為385.71g/m2-d、528.57g/m2-d、478.57g/m2-d。可知不管是水芙蓉還是布袋蓮，試驗二水生植物生長狀況均較試驗一、三為佳，而水芙蓉與布袋蓮之比生長速率與淨化率並非隨水體優養化程度而相對增加，亦即水生植物對污染物的吸收及耐受能力有一定限度，說明其生長狀況可能受營養鹽添加過量而有抑制現象。

關鍵字

廚餘 ； 厭氧消化 ； 資源化再利用

並列摘要

To understand the performance of a pilot scale anaerobic digestion system, a two-phased semi-CSTR system with a volume of 3000 L acidogenesis tank and a 12,000 L methanogenesis tank was investigated, and kitchen waste was the only substrate. Performance of this system was evaluated and liquid and solid by-products were investigated for resource recovery. The influent flowrate was 600 L/d and hydraulic retention time (HRT) of the methanogenesis tank was 20 days, and influent concentration and volumetric loading rate (VLR) were set at 90 g COD/L-d and 4.5 kg COD/ m3-day, respectively.
In the characterization of organic wastes, the average TCOD of kitchen waste was 134.6g/L, indicating a high organic content waste. The TS (% (w / w)) is about 19.8%, with a volatile solids VS (%TS) of 93.7%, showing a highly organic content in the solids. The TCOD/TKN and TCOD/TP were 48.83 and 215.4, respectively. Based on a nutrition requirement of COD: N: P = 400:7:1 for anaerobic microbial growth, indicating a sufficient supply of N and P from the kitchen waste.
When the system reached stable state, SS and TCOD removal efficiencies were 86.9 ± 3.41% and 77.3 ± 3.73%, respectively. Gas production was 6.95 ± 2.63 m3/day, with the CH4 and CO2 percentages of 65.76 ± 3.60% and 28.34 ± 3.77%, respectively. The percentage of CH4 matched the typical value of 65% from the literatures.
In the recovery of liquid by-product, Water Lotus and water hyacinth were planted for nutrient removal. Three runs of test were conducted by adding different loadings of the liquid fertilizer to the free water surface wetland. In the water hibiscus, generation times for the first, second, and third test were found to be 7.875, 5.33, and 5.68 days, respectively. As to hyacinth, generation times were 10.19, 6.86, and 7.62 days, respectively. In the harvest of water hibiscus, for the first (no addition of liquid by-product), second (15 kg/d addition of liquid by-product), and third (30 kg/d addition of liquid by-product) tests, the wet weight were 485.71, 914.29, and 828.57g/m2-d, respectively. As to hyacinth, they were 385.71, 528.57, and 478.57g/m2-d, respectively. Results show that the second run had the maximum plant growth, followed by the third and first runs. It was found that, growth rates of Water Lotus and water hyacinth and the purification rate are not proportional to the degree of eutrophication in the wetland. This result shows a limit in the uptake of nutrients from the plants, i.e., in the absorption of pollutants aquatic plants have their tolerance of certain limits to its growth stages and may be adversely affected by overloading the nutrients.

並列關鍵字

kitchen waste ； anaerobic digestion ； resource recovery

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