【摘要】：本文針對(duì)城鎮(zhèn)污水處理廠(chǎng)污泥處理處置設(shè)施因惡臭引起的二次污染問(wèn)題開(kāi)展調(diào)查研究,分析污泥熱干化過(guò)程中惡臭氣體的排放特性,并以氨(NH_3)、硫化氫(H_2S)和揮發(fā)性有機(jī)物(VOCs)(苯、甲苯、乙酸丁酯、乙苯、對(duì)(間)二甲苯、苯乙烯、鄰二甲苯)作為惡臭氣體的表征物質(zhì),研究干化溫度和含水率等因素對(duì)惡臭氣體釋放量的影響,建立減排措施。對(duì)于NH_3、H_2S和VOCs分別采用納氏試劑分光光度法、亞甲基藍(lán)分光光度法以及熱脫附-氣相色譜法來(lái)測(cè)量。NH_3、H_2S的釋放量均隨干化溫度的升高而增大,且存在釋放量突增溫度,分別在120℃和140℃附近。污泥含水率在25%~80%的范圍時(shí),NH_3的釋放量隨含水率的減少而明顯升高。而在污泥高溫干化過(guò)度后,H_2S的釋放急劇增加。對(duì)于VOCs,干化溫度低于140℃時(shí)VOCs的釋放量隨干化溫度的升高而增大,干化溫度高于140℃時(shí),揮發(fā)性有機(jī)物的釋放量隨干化溫度的升高而減小,其中以苯和甲苯的釋放量表現(xiàn)最為顯著。在80℃~160℃的干化溫度范圍內(nèi),VOCs的釋放總量在0.0889~1.8833 mg/m3之間。當(dāng)干化含水率接近于零時(shí),揮發(fā)性有機(jī)物的釋放量呈現(xiàn)突增趨勢(shì)。測(cè)得熱干化過(guò)程中其它惡臭氣體:三甲胺、甲硫醇、甲硫醚、二硫化碳、二甲二硫的濃度很低。通過(guò)減排實(shí)驗(yàn)可以得出,飽和石灰水是H_2S很好的吸收劑,水是NH_3較好的吸收劑,對(duì)于排放氣體濃度不高(≤2 mg/m3)且流量較小(≤0.8 L/min)的氣體而言,活性炭是VOCs較好的吸收劑。通過(guò)實(shí)驗(yàn)數(shù)據(jù)和產(chǎn)生機(jī)理分析,干化過(guò)程中惡臭氣體的影響因素主要是:含水率和溫度,其次pH值、微生物活性以及有機(jī)物含量等。因此,采用間接干化方式,在工程允許條件下,應(yīng)盡量使污泥在小于120℃下完成干化過(guò)程,而且要避免高溫下的干化過(guò)度。使用飽和石灰水、水和活性炭等吸收劑可有效降低惡臭氣體的濃度。
[Abstract]:In this paper, the secondary pollution caused by foul smell in sludge treatment facilities of urban sewage treatment plant is investigated and studied, and the characteristics of odor gas emission in the process of hot drying of sludge are analyzed, and ammonia (NH_3) is used. Hydrogen sulfide (H 2S) and volatile organic compounds (VOCs) (benzene, toluene, butyl acetate, ethylbenzene, p (m) xylene, styrene, o-xylene) were used as characterizing substances of odor gas, The effects of drying temperature and moisture content on the odour gas emission were studied and the emission reduction measures were established. NH_3,H_2S and VOCs were measured by Nessler reagent spectrophotometry, methylene blue spectrophotometry and thermal desorption gas chromatography, respectively. The amount of NH_3,H_2S released increased with the increase of drying temperature. The release temperature was about 120 鈩，

本文編號(hào)：2338183