Air quality assessment along Dhanbad - Jharia road

Road ambient air pollution status along Dhanbad – Jharia road isstudied and presented in this article. The selection of this areais made considering the importance of the road in Dhanbad district and the nature of activities taking place along the road, which reflect that the portion of road upto Dhansar can be considered as having commercial areas on both sides and that from Dhansar to Jharia as having industrial areas on both sides.For the assessment of the ambient air quality along the road monitoring is done at the following five locations: Indian Schoolof Mines (ISM), main gate; Bankmore; Dhansar police check post; Dhansar opencast project agent office and a residential house beside the Rajapur opencast project. The location of ISM, maingate is specially chosen as this represents a commercial shoppingcomplexes and the situation can be compared with that at Bankmore. Monitoring of ambient air quality is done following thestandard procedure prescribed in IS: 5182. In addition the concentration of lead, zinc, copper, iron, manganese, cadmium metals in SPM is also monitored. The ambient air quality is monitored in the months of September and November 1999, respectively, to represent monsoon and winter seasons. The SPM concentration observed at all the five locations in the winterseason is more than the permissible limits for commercial andindustrial areas. However, in the monsoon season, the SPM concentration is higher than the permissible limit at the twocommercial locations, i.e., ISM gate and Bankmore, while it isless than the prescribed limit for industrial areas at the remaining three locations. At the ISM gate and Bankmore the SPM generation is mainly by vehicular traffic while at other three locations it was in addition due to mining and other activities.     

Ammonium,Nitrate and Nitrite Nitrogen and Nitrate Reductase Enzyme Activity in Groundnut (Arachis hypogaea L.) Fields After Diazinon,Imidacloprid and Lindane Treatments

Impacts of diazinon (O,O-diethyl O-2-isopropyl-6-methylpyrimidin-4-yl phosphorothioate), imidacloprid [1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine] and lindane (1,2,3,4,5.6-hexachlorocyclohexane) treatments on ammonium, nitrate, and nitrite nitrogen and nitrate reductase enzyme activities were determined in groundnut (Arachis hypogaea L.) field for three consecutive years (1997 to 1999). Diazinon was applied for both seed- and soil-treatments but imidacloprid and lindane were used for seed treatments only at recommended rates. Diazinon residues persisted for 60 days in both the cases. Average half-lives (t_1/2) of diazinon were found 29.3 and 34.8 days respectively in seed and soil treatments. In diazinon seed treatment, NH₄ ⁺, NO₃ ^?, and NO₂ ^? nitrogen and nitrate reductase activity were not affected. Whereas, diazinon soil treatment indicated significant increase in NH₄ ⁺-N in a 1-day sample, which continued until 90 days. Some declines in NO₃ ^?N were found from 15 to 60 days. Along with this decline, significant increases in NO₂ ^?N and nitrate reductase activity were found between 1 and 30 days. Imidacloprid and lindane persisted for 90 and 120 days with average half-lives (t_1/2) of 40.9 and 53.3 days, respectively. Within 90 days, imidacloprid residues lost by 73.17% to 82.49% while such losses for lindane residues were found 78.19% to 79.86 % within 120 days. In imidacloprid seed-treated field, stimulation of NO₃ ^?N and the decline in NH₄ ⁺NO₂ ^?-N and nitrate reductase enzyme activity were observed between 15 to 90 days. However, lindane seed treatment indicated significant increases in NH₄ ⁺-N, NO₂ ^?-N and nitrate reductase activity and some adverse effects on NO₃ ^?N between 15 and 90 days.     

The Role of Headwater Streams in Downstream Water Quality1

Abstract: Knowledge of headwater influences on the water‐quality and flow conditions of downstream waters is essential to water‐resource management at all governmental levels; this includes recent court decisions on the jurisdiction of the Federal Clean Water Act (CWA) over upland areas that contribute to larger downstream water bodies. We review current watershed research and use a water‐quality model to investigate headwater influences on downstream receiving waters. Our evaluations demonstrate the intrinsic connections of headwaters to landscape processes and downstream waters through their influence on the supply, transport, and fate of water and solutes in watersheds. Hydrological processes in headwater catchments control the recharge of subsurface water stores, flow paths, and residence times of water throughout landscapes. The dynamic coupling of hydrological and biogeochemical processes in upland streams further controls the chemical form, timing, and longitudinal distances of solute transport to downstream waters. We apply the spatially explicit, mass‐balance watershed model SPARROW to consider transport and transformations of water and nutrients throughout stream networks in the northeastern United States. We simulate fluxes of nitrogen, a primary nutrient that is a water‐quality concern for acidification of streams and lakes and eutrophication of coastal waters, and refine the model structure to include literature observations of nitrogen removal in streams and lakes. We quantify nitrogen transport from headwaters to downstream navigable waters, where headwaters are defined within the model as first‐order, perennial streams that include flow and nitrogen contributions from smaller, intermittent and ephemeral streams. We find that first‐order headwaters contribute approximately 70% of the mean‐annual water volume and 65% of the nitrogen flux in second‐order streams. Their contributions to mean water volume and nitrogen flux decline only marginally to about 55% and 40% in fourth‐ and higher‐order rivers that include navigable waters and their tributaries. These results underscore the profound influence that headwater areas have on shaping downstream water quantity and water quality. The results have relevance to water‐resource management and regulatory decisions and potentially broaden understanding of the spatial extent of Federal CWA jurisdiction in U.S. waters.     

焦化废水生物脱氮半生产性试验启动研究

通过试验研究,探索了焦化废水生物脱氮半生产性启动条件,指出了顺利启动的关键技术是适宜的接种污泥及必须提供的环境条件。     

铁碳微电解法预处理猪场沼液中氨氮的研究

铁碳微电解是新型的污水处理技术,为了研究猪场沼液中氨氮的去除,将铁碳微电解技术应用于预处理难降解的厌氧沼液中的氨氮。经预先浸泡处理后的铁碳已达到吸附饱和,以此铁碳材料,分别采用了单因素实验和正交试验,用可见光分光光度法测试氨氮的浓度。单因素实验确定了铁碳微电解法影响氨氮去除的因素,选取pH值、反应时间、铁碳比为正交试验因素,通过正交试验得到,当温度为(20±1)℃,铁碳比为1∶1,pH值为3,反应时间为60 min时去除氨氮的效果最好,去除率为34.01%。铁碳微电解法预处理猪场沼液有一定的应用前景。     

外浮顶罐充氮管网设计及有效性试验验证

为了预防外浮顶罐密封圈雷击火灾,提出在密封圈内充入氮气的保护方法.将安全含氧量作为充氮的惰化目标,对外浮顶罐充氮管网进行设计,并通过试验来验证充氮管网的有效性.试验得到了充氮流量、进出气孔数量及管径与有效充氮时间的关系.若以142 m3/h的流量对容量为10×104 m3的外浮顶罐密封圈内充氮,则46.5 min内可以达到充氮惰化目标.雷电预警时间为60 ～ 90 min的条件下,充氮时间小于预警时间,表明所设计的管网是有效的.     

Influence of Riparian Seepage Zones on Nitrate Variability in Two Agricultural Headwater Streams

Riparian seeps have been recognized for their contributions to stream flow in headwater catchments, but there is limited data on how seeps affect stream water quality. The objective of this study was to examine the effect of seeps on the variability of stream NO₃‐N concentrations in FD36 and RS, two agricultural catchments in Pennsylvania. Stream samples were collected at 10‐m intervals over reaches of 550 (FD36) and 490 m (RS) on 21 occasions between April 2009 and January 2012. Semi‐variogram analysis was used to quantify longitudinal patterns in stream NO₃‐N concentration. Seep water was collected at 14 sites in FD36 and 7 in RS, but the number of flowing seeps depended on antecedent conditions. Seep NO₃‐N concentrations were variable (0.1‐29.5 mg/l) and were often greater downslope of cropped fields compared to other land uses. During base flow, longitudinal variability in stream NO₃‐N concentrations increased as the number of flowing seeps increased. The influence of seeps on the variability of stream NO₃‐N concentrations was less during storm flow compared to the variability of base flow NO₃‐N concentrations. However, 24 h after a storm in FD36, an increase in the number of flowing seeps and decreasing streamflow resulted in the greatest longitudinal variability in stream NO₃‐N concentrations recorded. Results indicate seeps are important areas of NO₃‐N delivery to streams where targeted adoption of mitigation measures may substantially improve stream water quality.     

小麦-玉米轮作体系农田氮素淋失特征及氮素表观平衡

连续6年采用渗漏计法研究了不同施氮处理下陕西关中小麦-玉米轮作区农田土壤90 cm深度处氮素(N)淋失特征和土壤-作物体系氮素表观平衡状况.结果表明:该地区农田氮素淋溶主要发生在降雨量较多的玉米季,且集中在8月和9月.监测期内,TN和NO-3-N年平均流失量分别为2.72~23.07 kg·hm-2和1.53~18.72 kg·hm-2,年流失率分别为0.65%~3.44%和0.82%~3.32%,且年总氮、硝态氮流失量均随年施氮量增加呈指数增加.氮素淋失形态中,NO-3-N比例较高,可占总氮淋失量的56.00%~81.00%,且随着氮肥用量的降低,其占总氮淋失量的比例也随之减小.可见,施氮量的大小在一定程度上会影响淋失液中各形态氮的比例.氮素表观平衡结果显示,随着施氮量提高,氮素在土壤中的残留和表观氮盈余均呈现指数增加趋势.长期施氮条件下,土壤-作物体系氮素表观损失率的幅度为32.60%~55.20%,土壤表观残留率为-0.17%~8.20%.多年监测结果表明,优化施氮模式下,作物不仅可以获得较高的产量和氮肥利用率,农田氮素淋失量也大幅降低,在节约肥料资源的同时减轻了潜在的环境风险.     

七星河湿地氨氧化古菌多样性和丰度及其与环境因子的相关性分析

以典型东北寒温带沼泽湿地——七星河湿地中芦苇和小叶樟植被下不同深度土壤中氨氧化古菌(Ammonia-Oxidizing Archaea,AOA)为研究对象,以编码氨氧化作用关键酶——氨单加氧酶(AMO)的amo A基因为分子标记,通过构建克隆文库和生物信息学方法分析数据,考察了不同植被环境中AOA多样性和丰度的垂直分布规律,及其与环境因子的相关性.研究结果表明,小叶樟植被土壤中AOA amo A基因多样性显著高于芦苇植被土壤中amo A基因多样性,芦苇植被土壤中AOA amo A基因多样性在深度为40~60 cm土层中最高,AOA多样性与NH+4-N、NO-3-N含量呈正相关;小叶樟植被土壤中AOA amo A基因多样性在深度为20~40 cm土层中最高,AOA多样性与NH+4-N、NO-3-N含量呈正相关.芦苇植被土壤中AOA丰度最低值出现于0~20 cm土层中,到20~40 cm土层中出现最高值,随着深度增加AOA丰度下降,AOA丰度则与NO-2-N含量呈正相关.小叶樟植被土壤中AOA丰度变化趋势与芦苇不同,最高值出现于0~20 cm土层中,随着土层深度增加AOA丰度下降,到40~60 cm出现最低值,AOA丰度与NO-2-N、TOC含量呈正相关.两种植被土壤中AOA丰度均在60~90 cm处有升高趋势.芦苇植被土壤中AOA丰度约是小叶樟植被土壤中AOA丰度的1.49倍.以上结果为湿地AOA生态功能及分布模式的研究提供基础数据,对全球氮循环的研究提供补充.     

污泥龄对低氧丝状菌活性污泥微膨胀系统的影响

为了研究污泥龄(SRT)对低氧丝状菌活性污泥微膨胀系统的影响,采用序批式间歇反应器(SBR)进行试验,分别按照厌氧/好氧和单级好氧的方式运行,考察了不同SRT下丝状菌污泥微膨胀系统的沉降性、脱氮除磷过程以及污泥特性的变化.结果表明,在好氧水力停留时间充分的条件下,低氧环境不但不会影响丝状菌微膨胀污泥的硝化进程,而且还有助于同步硝化反硝化(SND)、单级好氧除磷的发生.厌氧/好氧运行时,SRT与活性污泥的比硝化速率、比释磷速率和比吸磷速率成反比,与SND率和污泥的含磷量成正比.单级好氧运行时,减小SRT对硝化过程影响不大,但是有助于改善除磷效果.活性污泥的比耗氧速率(SOUR)、胞外聚合物(EPS)中多糖与蛋白质含量的比值、以及粘度都与SRT成反比.适当地减小SRT可以改善丝状菌微膨胀污泥的沉降性.厌氧/好氧运行时,厌氧段微氧环境易引发过度丝状菌污泥膨胀;单级好氧运行时,SRT过低会造成污泥黏性骤增而引发黏性污泥膨胀.