污泥热干化过程恶臭污染物排放特性研究

发布时间：2018-11-17 14:54

【摘要】：本文针对城镇污水处理厂污泥处理处置设施因恶臭引起的二次污染问题开展调查研究,分析污泥热干化过程中恶臭气体的排放特性,并以氨(NH_3)、硫化氢(H_2S)和挥发性有机物(VOCs)(苯、甲苯、乙酸丁酯、乙苯、对(间)二甲苯、苯乙烯、邻二甲苯)作为恶臭气体的表征物质,研究干化温度和含水率等因素对恶臭气体释放量的影响,建立减排措施。对于NH_3、H_2S和VOCs分别采用纳氏试剂分光光度法、亚甲基蓝分光光度法以及热脱附-气相色谱法来测量。NH_3、H_2S的释放量均随干化温度的升高而增大,且存在释放量突增温度,分别在120℃和140℃附近。污泥含水率在25%~80%的范围时,NH_3的释放量随含水率的减少而明显升高。而在污泥高温干化过度后,H_2S的释放急剧增加。对于VOCs,干化温度低于140℃时VOCs的释放量随干化温度的升高而增大,干化温度高于140℃时,挥发性有机物的释放量随干化温度的升高而减小,其中以苯和甲苯的释放量表现最为显著。在80℃~160℃的干化温度范围内,VOCs的释放总量在0.0889~1.8833 mg/m3之间。当干化含水率接近于零时,挥发性有机物的释放量呈现突增趋势。测得热干化过程中其它恶臭气体:三甲胺、甲硫醇、甲硫醚、二硫化碳、二甲二硫的浓度很低。通过减排实验可以得出,饱和石灰水是H_2S很好的吸收剂,水是NH_3较好的吸收剂,对于排放气体浓度不高(≤2 mg/m3)且流量较小(≤0.8 L/min)的气体而言,活性炭是VOCs较好的吸收剂。通过实验数据和产生机理分析,干化过程中恶臭气体的影响因素主要是:含水率和温度,其次pH值、微生物活性以及有机物含量等。因此,采用间接干化方式,在工程允许条件下,应尽量使污泥在小于120℃下完成干化过程,而且要避免高温下的干化过度。使用饱和石灰水、水和活性炭等吸收剂可有效降低恶臭气体的浓度。
[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，

本文编号：2338183