Bench Scale Evaluation of a Chemo-biochemical Process for Desulphurization of Gaseous Streams Containing Hydrogen Sulphide

Gases and suspended particulate matter are sampled and measured in situ at different sites within the city of Madrid to determinethe air pollution in the city. Lead concentrations in air are also determined. The information needed to assess levels of contaminants is obtained combining several analytical techniques,which provide real time concentration data of particles andgases. Particulate matter (PM), SO₂, CO, O₃, NO_x,NO₂, CH₄, total hydrocarbons and Pb were measured. Concentrations of pollutants are averaged over periods of hours,days, months and years. Variations of contaminant concentrationsin the last years are presented. Spatial and temporal distribution follows that of the traffic, the main source of pollution in Madrid City. Some specific measurements were carriedout to understand the influence of traffic emissions at themeasured site. Further, all measured concentrations never exceeded the European Union Directives.     

Effects of Silver on the Photocatalytic Degradation of Gaseous Isopropanol

Water, Air, & Soil Pollution - The decomposition of gaseous isopropanol (IPA) by UV/TiO2 process in an annular photoreactor was studied under various conditions such as UV light intensity and...     

城市河流及共生态治理规划研究

城市河流是城市空间的重要组成部分，具有多种社会经济功能和环境生态效益。目前我国城市河流存在着渠道被挤占填埋、硬化渠化以及污染严重等问题，并对整个城市生态环境造成严重影响，根据城市河流治理规划的发展趋势提出了还河流以空间、建设生态河堤、营造城市水景以及进行排污控制等项措施。     

Insights into Human Impacts on Streams from Tolerance Profiles of Macroinvertebrate Assemblages

We present the concept of assemblage tolerance profiles (ATPs) as an aid to freshwater bioassessment, and illustrate it with a practical example. An ATP describes the proportion of taxa in an observed assemblage that is estimated to tolerate each level of a specific stressor within a defined range. We used an extensive compilation of biomonitoring field data to estimate the lower tolerances for pH and dissolved oxygen (DO) of common families of macroinvertebrates in rivers of south-eastern Australia. These limits were then used to establish ATPs for macroinvertebrate assemblages at 30 sites across six river systems with varying levels of exposure to drainage from disused mines and discharges from sewage treatment plants. We hypothesised that sites with more exposure to mine drainage would have ATPs indicating greater tolerance of low pH, whereas sites with more exposure to sewage discharges would have ATPs indicating greater tolerance of low DO, and found that these hypotheses were confirmed for five of the six river systems. We suggest that stressor-specific ATPs, based on tolerances derived from either field distributions or laboratory tests, can help to verify or eliminate candidate causes of inferred human impacts on aquatic ecosystems.     

Observations on Gaseous and Aerosols Components of the Atmosphere and Their Relationships

Measurements of sulphur dioxide, ozone, ammonia, and soluble inorganic components of the atmospheric aerosol were made at a site in central southern England. Ammonia, ozone, and nitrate aerosol in winter were shown to exhibit significant diurnal variation. Ozone showed a typical diurnal variability, the magnitude of which was dependent upon wind speed. The lower night-time ozone concentrations at lower wind speeds were attributed to depletion inside nocturnal boundary layers by dry deposition. Ammonia, in contrast, showed a different behaviour, whereby the diurnal cycle was more pronounced at higher wind speeds, indicating that the cycle was unlikely to be the result of dry deposition at night. Ammonia concentrations showed a temperature dependence and the diurnal cycle of ammonia at this site appears to be the result of a temperature-driven emission signal. Of the total reduced nitrogen, NH_x (NH_x = NH₃ + NH₄ ⁺ aerosol), the phase was dominant and it is likely that more than 60% of the boundary layer NH_x is in this phase. The loss term of ammonia by reaction with acid sulphate aerosol is likely to be greater than that by dry deposition on a UK scale. Nitrate aerosol showed a positive correlation with sodium aerosol, once the effect of mutual correlations with sulphate and ammonium were removed. This correlation effect, in combination with evidence of a marine-oriented directional dependence of nitrate aerosol, and negative non sea-salt chloride aerosol from the same ‘marine’ sector, shows the potential importance of the formation of sodium nitrate aerosol from reaction of dinitrogen pentoxide, or possibly nitric acid or nitrogen dioxide with sodium chloride aerosol. It is likely that this provides the major route of nitrate into rain, not the scavenging of nitric acid vapour. Aerosol sulphate, nitrate, and ammonium have been measured at Harwell since 1954. Sulphate aerosol increased up until 1976 and has declined subsequently. Nitrate aerosol has increased over the whole period, whereas ammonium aerosol follows a similar pattern to that of sulphate, but with an equivocal direction of trend after 1976. Sulphate, nitrate and ammonium aerosol all show a similar statistically significant seasonality. A historical inventory of ammonia emissions shows a clear correlation with ammonium aerosol.     

Impacts on Streams from the Use of Sulfur-Based Compounds for Dechlorinating Industrial Effluents

We evaluate environmental impacts associated with sulfur-baseddechlorinating agents (sodium bisulfite and sodium thiosulfate)commonly used in industrial wastewater treatment by presentingdata from two examples for Department of Energy facilities inTennessee and Kentucky. One case involved a fish kill (> 24,000 fish) caused directly by sodium bisulfite; the second describes a near-miss situation resulting from over-dosing with sodium thiosulfate. Toxicity tests showed that overfeed situations withsodium thiosulfate or sodium bisulfite can depress pH and dissolved oxygen, causing mortality of fish. Bacteria also can metabolize some sulfur-based dechlorinating agents, thereby increasing the potential for reductions in pH and concentrationsof dissolved oxygen. Although removing toxic levels of chlorine is important when releasing chlorine-containing wastewaters to aquatic systems, waste-treatment plant operators should also beaware of significant impacts that can occur if sulfur-based dechlorinating agents are used to excess.     

Effect of Abiotic and Biotic Factors on the Photo-Induced Production of Dissolved Gaseous Mercury

This study was conducted to evaluate the contribution of environmental factors such as solar radiation and dissolved organic matter (DOM) on the photo-induced dissolved gaseous mercury (DGM) production through laboratory experiments using field water samples collected from wetlands. DGM production was more significantly influenced by UVB intensity than UVA. DGM formation was also significantly affected by DOM chemical structure/composition rather than its concentration. Increasing NO ₃ ^? concentration limited DGM production, but photo-induced Hg oxidation stimulated by NO ₃ ^? would possibly occur when the NO ₃ ^? level is more than twice the DOC level. The addition of phosphorus into the field water samples induced a slight increase of DGM production; however, the addition of nitrogen decreased DGM formation, suggesting that an increase of limiting nutrients in water may promote biotic DGM production. Experiments using a Selenastrum capricornutum monoculture solution showed that cell density had a positive effect on DGM production. Moreover, the difference in DGM production between filtered and unfiltered samples showed that S. capricornutum significantly produced biotic DGM under UVA irradiation. Finally, our results imply that environmental factors such as light intensity, DOM sources, and site-specific microorganisms can significantly affect photo-induced Hg transformation.     

Comparison of Wind Erosion on Various Agricultural Lands

This investigation was conducted to compare wind erosion on three different agricultural lands (dryland, wastewater-irrigated land, and freshwater-irrigated land) in southeastern Iran. This region consists of 11500 km² of arid to semi-arid lands and is one of the driest regions of the country with high population density. Average annual rainfall of the region ranges between 50 and 60 mm. The temperature data indicate that July is the warmest month, when the temperature rises to more than 50 °C, and January is the coldest month of the year, with a minimum temperature of ?12 °C. The warm winds blow over the region of Sistan for about 120 days from June to September. The dominant wind directions are north and northwest. Twenty plots were designed randomly (in a completely randomized design) in this study to compare two irrigated areas, freshwater-irrigated land and wastewater-irrigated land, to dryland (control fields). The treatments were repeated three times. Ten data sets were taken during the experimental period, and the means were calculated and reported. The data indicated that wastewater-irrigated land benefitted from reduced soil erosion, increased soil fertility status (i.e., soil organic matter and nutrient contents), and increased soil moisture content. Soil losses by wind erosion in the wastewater-irrigated land, freshwater-irrigated area, and dryland in the study area were 185.2, 339.8, and 554.4 tons ha^?1, respectively. In addition, the study sites lost 1.3, 2.4, and 4.6 cm of soil by wind erosion, respectively.     

不同施氮量对冬小麦田氮去向和气态损失的影响

该文研究氮肥对冬小麦田肥料氮素去向和气态损失的影响。通过布置田间微区试验,采用15N微区示踪技术和密闭室间歇通气法、密闭式静态箱法田间原位监测冬小麦氮肥的去向和气态损失。随着施氮量的增加,冬小麦产量和地上部吸氮量增加,但当施氮量高于150 kg/hm2时,产量出现降低的趋势,地上部吸氮比例也以土壤氮为主转变为肥料氮为主。4个施氮处理N75、N150、N225和N300的0-100 cm的土壤氮残留分别为32.6,26.8,34.7,40.6 kg/hm2。冬小麦田间土壤氨挥发排放总量随着施氮量的增加而增加,排放量在6.03～13.26kg/hm2之间,占施N量的5.4%～11.4%。N2O排放造成的氮素损失比例为0.08%～0.28%,苗期是冬小麦季N2O排放的主要时期。化肥氮在冬小麦当季作物吸收、土壤残留及损失量分别为37.2%～50.2%,26.7%～40.6%,17.4%～22.2%,且随着施氮量的增加而升高。在本试验条件下,150 kg/hm2是适宜的氮肥用量,产量最高,土壤氮残留最低,气态损失占肥料氮总损失的比例高于75 kg/hm2处理,但差异不显著(p0.05)。因此控制氮肥用量是提高氮肥利用率的一项关键措施。     

Sand-Sized Limestone Treatment of Streams Impacted by Acid Mine Drainage

Direct single point, instreamapplications of limestone sand were made in twostreams severely acidified by acid mine drainage. After high flows distributed the sand downstream,dissolution of the limestone significantly reduced theacid loads in both streams. Data from the treatedstream sections and laboratory experiments showed thatthe efficiency of treatment was more dependent onlimestone particle size than CaCO₃ content. Results from the stream treated with a narrow range oflimestone sand-sized particles showed a highutilization efficiency with nearly completedissolution of the limestone. The data indicated thatmonthly addition of limestone sand may be sufficientfor complete treatment of the streams studied. Ananalysis of such a treatment scheme indicated it to behighly cost efficient when compared to other activeand passive treatment systems.     

Comparison of Cadmium Ion Adsorption on Various ACTIVATED CARBONS

Studies on the removal of cadmium(II) ions from aqueous solutions by adsorption on various activated carbons [commercial activated carbon (CAC) and chemically prepared activated carbons (CPACs) from raw materials such as straw, saw dust and datesnut] have been carried out with an aim to obtain information on treating effluents containing Cd(II) ions. Factors influencing the adsorption of Cd(II) ions from aqueous solution by ACs have been investigated by following a batch adsorption technique at 30± 1 ^°C. The percentage removal increased with decrease in initial concentration and particle size of CPACs and an increase in contact time, dose and initial pH of the solution. Adsorption process was inhibited by the added electrolytes. The adsorption data were fitted with the Langmuir, Dubinim–Radushkevich and Freundlich isotherms and first-order kinetic equations viz., first-order, Lagergren and Bhattacharya–Venkobachar equations and intra-particle diffusion model. The kinetics of adsorption is first order with intra-particle diffusion as one of the rate determining steps. Thermodynamic parameters were obtained from equilibrium constants measured at 30, 35 and 40 ^°C (Error = ± 1 ^°C). Results of the studies on adsorption of Cd²⁺ ions from simulated wastewater were compared with that of CAC and Tulsion CXO-9(H), a commercial ion exchange resin/cationic resin (CR). Straw carbon showed the maximum adsorption capacity towards Cd²⁺ ions and a high value of rate constant of adsorption. Straw carbon is an alternative low-cost adsorbent to CAC.     

堆肥中大肠菌群等粪便污染指标菌的残留状况调查

从日本九州地区23处堆肥化设施采集了以牛粪、鸡粪、污泥和餐厨垃圾为原料的堆肥试样29个,调查了大肠菌群等粪便污染指标菌的残留状况。结果表明,使用DESO培养基有11个试样被检出大肠菌群,检出率达38%,菌数在102~106 cfu.g-1的范围。使用API 20E鉴定系统对4个试样中的21个分离纯化菌株进行了菌种鉴定,发现有大肠菌群属的Escherichia coli、Escherichiavulneris、Pantoea sp.和Buttiauxella agrestis,以及非大肠菌群属的Serratia marcescens等肠内细菌科细菌。采用血清凝集试验对5株E.coli的病原性检测结果均为阴性。进一步针对6处堆肥设施的堆肥发酵过程中大肠菌群的消长追踪发现,大肠菌群数从原料到成品出现了逐渐减少直至消失、暂时消失、未完全消失、完全未检出4种走势,显示即使堆肥发酵温度在60℃以上,大肠菌群也有可能通过交叉污染等途径残留在堆肥成品中。     

Dispersion of Odorous Gaseous Compounds Emitted from Wastewater Treatment Plants

Municipal wastewater treatment plants (WTP) emit odorous compounds that produce nuisance to the workers and nearby residents. Several chemical compounds contribute to odour problems, among them, sulphurous organic compounds, hydrogen sulphide, phenols and indoles, ammonia, volatile amines and volatile fatty acids. In the current study, hydrogen sulphide (H₂S) concentrations were measured during the summer period of 2007 by a portable handheld device at the WTP of Chania City (Greece). Measurements were taken in several places within the facility. The highest hydrogen sulphide levels were measured close to the primary sedimentation tanks and the tanks where the recycled activated sludge is mixed, the sludge from the primary sedimentation tanks reaching 30 ppm. In conjunction with the measurements, the Gaussian dispersion model AERMOD code was modified in order to estimate the maximum odour concentration for very short time steps using peak-to-mean ratios. The probability of detection of H₂S exceeds 50% at 400 m distance from the main emission sources (time interval of 5 s) with a relative high degree of annoyance (3.2 AU) under typical summer period conditions. Furthermore, relations between odour annoyance and odour exposure concentrations have been embedded in the model, in order to express the odour impacts in terms of probability of detection and degree of annoyance of the population near the WTP of Chania.     

福建闽东诸小河泥沙及其变化分析

根据50年实测水文资料,分析了闽东诸小河泥沙年内年际变化和来水、产沙的因果关系及造成水土流失的主要原因。掌握该地区泥沙变化规律,对流域水土资源开发、利用和保护有着重要意义。     

Effect of Adding Flue Gas Desulphurization Gypsum on the Transformation and Fate of Nitrogen during Composting

The objective of this study was to investigate the effect of adding flue gas desulphurization gypsum (FGDG) on the transformation and fate of nitrogen during co-composting of dairy manure and pressmud of a sugar refinery. The ammonia absorption of FGDG was investigated. The changes in compost temperature, pH, electrical conductivity (EC), moisture, organic matter, the C/N ratio, Kjeldahl N, NH₄⁺-N, NO₂^?-N, NO₃^?-N were assessed. The addition of FGDG did not significantly affect compost temperature, pH, EC, moisture, and organic matter degradation. However, the addition of FGDG significantly increased the NH₄⁺-N content in the compost during the thermophilic phase, and the NH₄⁺-N maximal content in the compost with FGDG (CP+G) was 59.9% more than that in the compost without FGDG (CP–G). FGDG was thought to create the formation of (NH₄)₂SO₄ and the cation exchange between NH₄⁺ and Ca²⁺. The NO₂^?-N content in the CP+G peaked on day 15, and was not observed in the CP–G. In the final compost products, the NO₃^?-N concentration in the CP–G was more than that in the CP+G, which was 1451 (CP–G) and 1109 mg·kg^?1 (CP+G) dry material. This might be due to the NO₂^? accumulation in the CP+G, which accelerated N loss in the form of N₂O. There is a strong correlation between N₂O emission and NO₂^?-N accumulation in the composting process. Compared with the original N content in the compost mixture, the N loss in CP–G and CP+G were 15.0 and 10.8%, respectively. These results revealed that NH₄⁺-N conservation effect was improved during the thermophilic phase and the total N loss was mitigated by adding FGDG into composting materials. FGDG could be utilized as a potential amendment to conserve nitrogen during composting.     

Soybean Residue Effect on Carbon Fractions and Gaseous Nitrogen Losses at Contrasting Moisture Contents

Most published studies related to crop effects on denitrification are not continuous and are based on the growing period. The objective of this work was to evaluate the effect of different amounts of soybean stubble, under different soil moisture contents, on gaseous nitrogen (N) losses by denitrification from an agricultural soil. The following soil moisture treatments were reached by adding distilled water to soil cores of a typic Hapludoll: 50 and 100% of water‐filled porosity space (WFPS). Residue treatments included no application of residues, amendment with 2600 kg ha^?1 of soybean residues, and amendment with 5200 kg ha^?1 of soybean residues. Cumulative nitrous oxide + dinitrogen (N₂O + N₂) emissions displayed great variability, ranging between 0 and 581.91 µg N kg^?1, which represented 0 to 3.93% of the N residue applied. Under 50% WFPS moisture conditions, statistical differences in cumulative N₂O + N₂ emissions between residue treatments were not detected (p = 0.21), whereas at saturation conditions, cumulative N₂O + N₂ emissions decreased with the application of increasing amounts of soybean residues (p = 0.017). Daily and cumulative N₂O + N₂ emissions significantly increased as soil moisture increased, except at soils amended with 5200 kg ha^?1 of soybean residues; this lack of statistical difference was probably due to the immobilization of native mineral N. Under 50% WFPS soil moisture contents, aeration seemed to be the main factor controlling redox conditions, limiting the denitrification process, and preventing differences in N emissions between residue treatments. The application of soybean residues to saturated soils notably decreased N₂O + N₂ emissions by denitrification through a strong mineral N immobilization into organic and nondenitrifiable forms.     

Effects of Restored Stream Buffers on Water Quality in Non-tidal Streams in the Choptank River Basin

Restoration of riparian buffers is an important component of nutrient reduction strategies in the Chesapeake Bay watershed. In 1998, Maryland adopted a Conservation Reserve Enhancement Program (CREP), which provides financial incentives to take agricultural land out of production to plant streamside vegetation. Between 1998 and 2005, 1–30% of streamside vegetation (average?=?11%), was restored to forest or managed grass in 15 agriculturally dominated sub-basins in the Choptank River basin, a tributary of Chesapeake Bay. Pre-existing forested buffers represented 10–48% of the streamside (average?=?33%), for a total of 12–61% buffered streamsides (average?=?44%). Using multi-year water quality data collected before and after CREP implementation (1986, 2003–2006), we were unable to detect significant effects of CREP on baseflow nutrient concentrations based on the area of restored buffer, the percentage of restored streamside, or the percentage of total riparian buffer in the sub-basins (p?>?0.05). Although CREP increased the average buffered streamside from 33% in the 1990s to 44% by 2005, N and P concentrations have not changed or have increased in some streams over the last 20 years. Reductions may not have occurred for the following reasons: (1) buffer age, width, and connectivity (gaps) between buffers are also important to nutrient reductions; (2) agricultural nutrient inputs may have increased during this period; and (3) riparian buffer restoration was not extensive enough by 2005 to have measurable affects on the stream water quality in these sub-basins. Significant effects of CREP may yet be resolved as the current CREP buffers mature; however, water quality data through 2006 in the Choptank basin do not yet show any significant effects.     

Effects of Afforestation on Acidity and Invertebrates in Danish Streams and Implications for Freshwater Communities in Denmark

The relationship between acidity and benthic invertebrate communities was investigated in two small streams in coniferous forests in central Jutland, Denmark, during 1992 and 1993. Stream pH was acid (mean pH 4.8 and 5.4) and alkalinity fluctuated greatly with mean values around zero. During rain events, water from springfed reaches upstream were mixed downstream with brown humic acid water with high aluminium content, and pH declined from circumneutral near the springs down to pH below 4 over a very short distance (0.5–1.5 km). The benthic invertebrate communities in the most acidic downstream reaches of both streams were dominated by filipalpian stoneflies, mainly Leuctra nigra (Olv.). Community composition remained very similar throughout the sampling period despite variations in pH. In the upper (neutral) reaches invertebrates intolerant of low pH such as Gammarus pulex L. were found. The concentrations of chloride and sulphate in the streams were more than double the concentrations in a nearby moorland stream indicating a strong impact of acidifying atmospheric deposition on the two forest streams. Results of this study indicate that afforestation with conifers on sandy Danish soils with low buffering capacity (about 25% of the total Danish land area) may lead to an increased acidification of surface waters and thereby also to an impoverished aquatic fauna.     

不同土壤改良剂对土壤生化性质与烤烟产量的影响

通过田间试验,探讨以石灰、粉煤灰、白云石、废菌棒和化肥构成的不同组合改良剂对土壤微生物数量、酶活性和烤烟产量的影响。结果表明施用不同组合改良剂后,耕层土壤细菌、放线菌、磷细菌、钾细菌和纤维素分解菌的数量、土壤过氧化氢酶、脲酶、磷酸酶和纤维素酶的活性及烤烟产量均比对照有不同程度提高,其中添加废菌棒处理的微生物数量、酶活性和烤烟产量变化明显高于无添加废菌棒处理,且均以“石灰+菌棒+常规化肥”改良剂组合变化最明显,差异显著性检验表明该组合处理的5种微生物数量、4种酶活性及烤烟生物和经济产量与对照相比差异均达极显著水平。相关分析表明耕层土壤5种微生物数量和4种酶活性与烤烟生物及经济产量均呈极显著的正相关。表明施用不同组合改良剂能促进土壤细菌、放线菌、磷细菌、钾细菌及纤维素分解菌的繁殖,增强过氧化氢酶、脲酶、磷酸酶及纤维素酶的活性,促进烤烟产量的提高,其中以“石灰+菌棒+常规化肥”组合改良剂的效果最好。     

Gaseous Emissions During the Coal Mining Activity and Neutralizing Capacity of Ammonium

This paper presents the simultaneous measurement of atmospheric concentration of gaseous NH₃, SO₂ and NO₂, and particulate NH ₄ ⁺ released from the mining activities of coal-mine area, Tirap colliery, Margherita (Assam). Gas samples were collected by impinger method and were analyzed colorimetrically. The vapor-phase concentration of NH₃, SO₂, and NO₂ range between 4.7?C40.03, 1.47?C6.14, and 1.92?C2.40???g/m³. The NH ₄ ⁺ concentration in PM₁₀ and PM_2.5 ranges between 0.02?C0.07 and 0.008?C0.03???g/m³, respectively. Moderately high concentrations of NH₃ and SO₂ on the first day were due to the coal-burning activity near the sampling site, while the low concentration of NO₂ is due to less vehicle density near the sampling point. All the observed concentrations are below than those reported for the urban areas and the prescribed limit fixed by National Ambient Air Quality Standard, India. Study indicates that ammonia is the major neutralizing agent for sulfate and nitrate ions present in the particulate matter during mining activities.