A Study of Sorptive Loss Patterns for Reduced Sulfur Compounds in the Use of the Bag Sampling Method

In this work, the basic properties of the bag sampling method were examined and characterized in terms of recovery rate with respect to four reduced sulfur compounds (RSC) including H₂S, CH₃SH, DMS, and DMDS. For this comparative study, two types of calibration approaches were performed to evaluate the relative RSC loss due to bag sampling. As a reference calibration tool, a syringe dilution (SD) method was applied. The working standards prepared by diluting the primary standard in a gas-tight syringe (as a mixing chamber) were injected to the GC/PFPD through a loop-injection system to yield a background calibration information. In contrast, the target calibration was performed based on a bag dilution (BD) method. To this end, working standards for multiple calibration points were prepared by two different bag types (Tedlar bag (TB) and polyester bag (PB)). These standards were then drawn by the same syringe and injected into the GC/PFPD via loop. On the basis of these comparative analyses, both absolute and relative differences in RSC recovery rates (RR) were evaluated (e.g., comparison of wall-loss effect). The results indicate that TB has a mean RR of 87% for the four RSC with their values ranging from 82 (CH₃SH) to 91% (DMDS). On the other hand, the results of PB generally exhibited slightly reduced RR with their mean values of 77% (range: 73% of H₂S to 83% of DMS). The results of this study generally suggest that the losses of RSC samples, while inevitable with the bag sampling method, exhibit certain patterns between different RSCs and between different grab sampling materials.     

Short-term Distributions of Reduced Sulfur Compounds in the Ambient Air Surrounding a Large Landfill Facility

In order to explore the environmental behavior of reduced sulfur compounds (RSC) as malodorous components emitted from diverse source processes, the distribution characteristics of four sulfur (S) compounds - hydrogen sulfide (H₂S), methyl mercaptan (CH₃SH), dimethyl sulfide (DMS: (CH₃)₂S), and dimethyl disulfide (DMDS: (CH₃)₂S₂) – were investigated in a municipal landfill area. In the course of this study, their ambient concentration levels were measured during two time periods from 13 individual spots selected as a function of distance from the center of the landfill site. The results generally indicated the absolute dominance of H₂S over the other S compounds investigated (up to 5 km radius) such that their mean values were found as 1415 (H₂S), 148 (DMS), 20.6 (CH₃SH), and 14.4 ppt (DMDS). When our data were compared in terms of either varying distance from the source or relationship with meteorological conditions, the H₂S data sets were most evident to reflect the potential effects of strong source processes in the landfill environment, relative to other S gases (or to volatile organic compounds measured concurrently). The results of this study further indicated the relatively good correspondence between the measured H₂S concentration level and humans' intuitive sensory of odor and nuisance.     

脱氮硫杆菌氧化硫化氢过程中的生物氧化和化学氧化

在好氧反应器中研究了不同条件下H2S生物氧化和化学氧化之间的关系.结果表明,在pH为6～8、温度为25～35℃和溶解氧浓度为10.5 mg·L-1时,当硫化氢进气摩尔流速稳定在2.1 mmok·L-1·h-1时,脱氮硫杆菌(Thiobacillus denitrificans)氧化硫化氢的生物氧化速率可达到1.9 mmol·L-1·h-1以上,此时硫化物在液相的累积摩尔速率和H2S出口摩尔流速均很低;化学氧化速率随pH、温度和溶解氧浓度的增加而增大,可达到0.33 mmol·L-1·h-1～0.45 mmol·L-1·h-1;化学氧化速率在最佳菌体生长条件范围内占总氧化速率的比值较小,为8.6～19.1%,而随着pH值、温度的降低这一比值上升至29%～43.7%.     

EDTA及其回收溶液治理重金属污染土壤的研究

试验结果表明,EDTA能够有效地萃取土壤重金属,由于其价格较贵和不易被降解等特点,限制了它的广泛运用.在运用MINTEQA2模型对萃取液中重金属离子形态分析的基础上,选用Na2S沉淀法将重金属从EDTA萃取液中有效分离.同时将回收的EDTA连续进行萃取土壤重金属,由于回收EDTA浓度下降的原因,其效果比新鲜EDTA的要稍微差一点,但从经济和效率上来说,仍旧可以用来治理重金属污染的土壤.     

复合式生物除臭反应器处理城市污水处理厂恶臭气体

采用复合式生物除臭反应器处理北京某城市污水处理厂污泥浓缩池和脱水间散发的恶臭气体,研究了反应器对恶臭气体的净化效果和微生物悬浮生长区与附着生长区内的生物特性及对恶臭污染物的去除能力。该污水处理厂的恶臭气体中主要发臭物质为硫化氢和氨,除臭反应器的运行结果表明,在设备稳定运行期间,进气中硫化氢和氨的浓度分别为0.21～22.61 mg/m³和0.1～0.5 mg/m³,而出气中硫化氢浓度在0～0.06 mg/m³,氨浓度为0～0.02 mg/m³。对反应器内部测试表明,微生物悬浮生长区和附着生长区对硫化氢和氨都有一定的去除,但去除机理不同。硫化氢主要被附着生长区的嗜酸性硫细菌生物氧化,少量硫化氢在悬浮区溶于水被中性硫细菌氧化;氨主要在悬浮区靠生物硝化作用去除,少部分氨在附着区被去除,且多因化学中和作用转移到填料所含的水中。     

磷酸活化粘胶基活性碳纤维吸附甲硫醚的实验研究

不同活化条件下,以磷酸为活化剂制备粘胶基活性碳纤维(VACF),研究VACF对甲硫醚静态吸附的效果.随着活化温度的升高,活性碳纤维对甲硫醚的吸附率增大;碳化活化时间达1h后,活性碳纤维对甲硫醚的吸附性能没有明显变化;活化剂浓度为1:3(磷酸与水体积比)、浸泡的时间为10h时,活性碳纤维对甲硫醚的吸附效果最佳.     

一株新的反硝化短程除硫菌的鉴定及主要培养因素筛选

依据反硝化除硫原理,以味精废水污泥为种泥,利用全混流反应器富集并分离出同步反硝化短程除硫菌(SNBI),采用传统与现代分子生物学相结合的手段对其鉴定,以确定其分类地位;同时对SNB1的主要培养因素(营养和环境)进行筛选.结果表明:SNB1的形态特征及生理生化指标与Thauera selenatis最相似,同源性达99.0%,属短杆菌属,尚无中文命名;生理生化指标、富集条件及富集过程物料平衡显示SNB1是一株兼性厌氧反硝化除硫菌;培养SNB1的最佳碳源为蔗糖,最佳氮源为蛋白胨,最佳培养温度为35℃,最适宜pH范围为7～9;最佳条件培养时,OD_(650)和对数细菌数量(CFU)呈直线相关,相关系数R~2=0.981.     

基质浓度冲击对同步厌氧生物脱氮除硫反应器性能的影响

采用上流式厌氧污泥床(UASB)反应器研究了基质浓度冲击对同步厌氧生物脱氮除硫反应器性能的影响.根据反应器性能对基质浓度冲击的响应特征,可将基质浓度冲击过程分为冲击期、惯性期和恢复期3个阶段.基质浓度的冲击效应与冲击强度有关.冲击强度较低(1.5倍以下的基质浓度冲击)时,反应器性能所受的影响较小;冲击强度较高(2.0倍以上的基质浓度冲击)时,反应器性能所受的影响较大,出水pH值及基质浓度显著升高.在所试验的冲击强度范围内,反应器性能受扰后均可恢复稳态,恢复时间均小于30h(7.5HRT).出水硫化物浓度对基质浓度冲击的响应较为灵敏,其受扰时的浓度值可高达10.13mg /L,为受冲击前稳定运行时的18倍,可用作反应器性能变化的指示参数.     

Cd对前沟藻(Amphidinium hoefleri)生产二甲基硫(DMS)影响的实验研究

为了探讨Ｃｄ污染对海藻ＤＭＳ生产的可能影响,以模拟实验方法,为期３周进行Ｃｄ对海洋甲藻类的前沟藻（Ａｍｐｈｉｄｉｎｉｕｍ ｈｏｅｆｌｅｒｉ）生产ＤＭＳ的实验室研究。结果表明,Ｃｄ可以抑制前沟藻种数数量的增长,对照组藻细胞最大数量是高浓度组（１０ｍｇ／Ｌ）的２５倍;Ｃｄ可以促进前沟藻细胞生产ＤＭＳ,其中高浓度组细胞ＤＭＳ产率大约是对照组的１０倍;Ｃｄ对藻数量的抑制作用和对藻生产ＤＭＳ的促进作用共同作     

新疆博斯腾湖水环境容量研究

首先对博斯腾湖水环境功能进行了分区,利用箱模型分区模拟计算了博斯腾湖不同水质目标条件下的COD,TN以及盐污染物的最大允许入湖量,在现状污染负荷的基础上确定了目标削减量与削减率,为博斯腾湖流域水污染防治提供了技术依据。