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|Other Titles: ||Study on the stabilization of sludge and screen waste from hospital wastewater treatment plant by thermophilic aerobic digestion|
|Authors: ||柯宜汶;Ke, Yi-Wen|
|Keywords: ||高溫好氧消化;生物固體物;廢棄污泥;篩渣;安定化;致病菌;thermophilic aerobic digestion (TAD);biosolids;waste sludge;screen residue;stabilize;pathogens|
|Issue Date: ||2014-01-23 14:48:01 (UTC+8)|
|Abstract: || 醫院廢水處理場廢水來源可能來自隔離病房或接觸病人之生活污水，性質與一般事業廢水或一般生活污水大不相同。醫院廢水處理場所產出之生物固體物(篩渣及廢棄污泥)可能含有許多未知的致病菌，若未妥善處理處置將會導致病菌傳播的危機。篩渣物中主要含有廚餘或糞便等顆粒較大之有機物質，具有令人厭惡之臭味。|
研究結果得知結合篩渣及污泥共同進行高溫好氧消化可快速降低固體物產量。當固體物配比為篩渣:污泥=1:2.5(SR/SL=0.48)，會有較佳固體物削減成效，反應速率常數Kd為0.994(day-1)。好氧消化系統中將溫度控制於50℃會有較佳之固體物削減成效，單純污泥消化系統TS消化率達51.16%；VS消化率達55.82%。結合篩渣及污泥系統TS消化率達47.59%；VS消化率達51.85%。經過2～3天的好氧消化程序後，系統中已近乎沒有異味的產生。由有機酸定性分析推估，本研究之好氧反應途徑是依循TCA cycle進行。將操作溫度控制為50℃、70℃時，大腸桿菌菌落數由無法計數削減至2.6*105 CFU/100mL及N.D.由此可得知高溫好氧消化具有良好的滅菌效果。
Hospital wastewater treatment plant might receive wastewater from isolation ward or sewage contacted by patients, therefore, their properties are different from general industrial or domestic sewage .Biosolids produced from hospital wastewater treatment plant include waste sludge and screen residue, which might contain lots of unknown pathogens. It will cause the crisis of germs-spreading if without proper handling. Besides, screen residue contains solids rich in organic matters such as food waste, excrements, etc. and smells stinky.
Thermophilic aerobic digestion (TAD) process has the advantages of easy operating, small area required, stable system, rapid biomass degradation, and efficiently pathogen inactivation. In this study, we used TAD process to stabilize and reduce the biosolids produced by hospital wastewater treatment plant. At the same time, pathogens were inactivated by TAD process, too. The emphasis in our study was combine waste sludge and screen residue to precede TAD process, in order to improve the efficiency of the degradation of organic matters and solve the problem of odor-emission.
In this study VS/TS was used as a decomposable index, the digestion ratio of the total and volatile solid and water quality analysis of filtrate were used as the digestion efficiency indexes, E. coli colonies was used as the pathogen inactivation index. The experiments were operated in batch model. The efficiency of TAD process by explored by modulating sludge retention, proportions of biosolids and operating temperature. Different waste sludge and screen residue ratio were exam, in order to find the optimal combination and different solid liquid ratio, and also realize food loading to the microorganisms. After that, the effects in different operating temperature were discussed.
The results found that, combining waste sludge and screen residue in TAD process can degrade biomass rapidly. The better digestion efficiency was screen residue : sludge = 1:2.5(SR/SL=0.48). The reaction rate constant (Kd) is 0.994 day-1.When the digestion temperature controlled at 50℃,we got the better digestion efficiency. In sludge digestion system, the TS and VS digestion efficiency were 51.16% and 55.82% respectively; in sludge and screen residue digestion system, the TS and VS digestion efficiency were 47.59% and 51.85% respectively. After 2-3 days of digestion time, the offensive odor was vanished. According to the qualitative analysis of organic acid, TAD process was found to fit the pathway of TCA cycle. When the operating temperatures were controlled at 50℃ and 70℃, E. coli colonies in biosolids sharply reduced from unable counting to 2.6*105 CFU/100mL and N.D. respectively.
|Appears in Collections:||[水資源及環境工程學系暨研究所] 學位論文|
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