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1.
Environmental monitoring of leachate quality from an open municipal solid waste dumping site in Tunceli, Turkey was studied in this research. The most commonly examined pollution parameters were determined on a seasonal basis. The annual average 5-day biological oxygen demand (BOD5) and chemical oxygen demand (COD) values of station points were measured as 70 and 425 mg/L, respectively, and also the average BOD5/COD ratio (a measure of biodegradability) was calculated as 0.20. The low ratio of biodegradability and slightly alkaline pH values in the leachate samples indicated that the site was characterized by methanogenic conditions. The mean ammonium-nitrogen (NH4 +-N) and corresponding phosphate (orthophosphate) values were assayed as 70 and 11 mg/L, respectively. The average solids content in the leachates was measured as 4,681 mg/L (total solids) and 144 mg/L (suspended solids). Very low concentrations of iron, manganese, copper, and zinc in the leachate samples were found and the concentration of cadmium was measured below detection limits. Excessive amount of nutrients and high organic and inorganic pollutant content in the leachates pose serious pollution potential to the environment. Since no drainage system or bio treatment exists in this open dumping site, high permeability of natural soil at the site and in the surrounding area and very fractured and crackled rocks under natural soil are indicators of high groundwater pollution potential in this site.  相似文献   

2.
The Minnesota River Basin (MRB), situated in the prairie pothole region of the Upper Midwest, contributes excessive sediment and nutrient loads to the Upper Mississippi River. Over 330 stream channels in the MRB are listed as impaired by the Minnesota Pollution Control Agency, with turbidity levels exceeding water quality standards in much of the basin. Addressing turbidity impairment requires an understanding of pollutant sources that drive turbidity, which was the focus of this study. Suspended volatile solids (SVS), total suspended solids (TSS), and turbidity were measured over two sampling seasons at ten monitoring stations in Elm Creek, a turbidity impaired tributary in the MRB. Turbidity levels exceeded the Minnesota standard of 25 nephelometric units in 73% of Elm Creek samples. Turbidity and TSS were correlated (r 2?=?0.76), yet they varied with discharge and season. High levels of turbidity occurred during periods of high stream flow (May–June) because of excessive suspended inorganic sediment from watershed runoff, stream bank, and channel contributions. Both turbidity and TSS increased exponentially downstream with increasing stream power, bank height, and bluff erosion. However, organic matter discharged from wetlands and eutrophic lakes elevated SVS levels and stream turbidity in late summer when flows were low. SVS concentrations reached maxima at lake outlets (50 mg/l) in August. Relying on turbidity measurements alone fails to identify the cause of water quality impairment whether from suspended inorganic sediment or organic matter. Therefore, developing mitigation measures requires monitoring of both TSS and SVS from upstream to downstream reaches.  相似文献   

3.
Forty-one livestock drinking water ponds in Alabama beef cattle pastures during were surveyed during the late summer to generally understand water quality patterns in these important water resources. Since livestock drinking water ponds are prone to excess nutrients that typically lead to eutrophication, which can promote blooms of toxigenic phytoplankton such as cyanobacteria, we also assessed the threat of exposure to the hepatotoxin, microcystin. Eighty percent of the ponds studied contained measurable microcystin, while three of these ponds had concentrations above human drinking water thresholds set by the US Environmental Protection Agency (i.e., 0.3 μg/L). Water quality patterns in the livestock drinking water ponds contrasted sharply with patterns typically observed for temperate freshwater lakes and reservoirs. Namely, we found several non-linear relationships between phytoplankton abundance (measured as chlorophyll) and nutrients or total suspended solids. Livestock had direct access to all the study ponds. Consequently, the proportion of inorganic suspended solids (e.g., sediment) increased with higher concentrations of total suspended solids, which underlies these patterns. Unimodal relationships were also observed between microcystin and phytoplankton abundance or nutrients. Euglenoids were abundant in the four ponds with chlorophyll concentrations >?250 μg/L (and dominated three of these ponds), which could explain why ponds with high chlorophyll concentrations would have low microcystin concentrations. Based on observations made during sampling events and available water quality data, livestock-mediated bioturbation is causing elevated total suspended solids that lead to reduced phytoplankton abundance and microcystin despite high concentrations of nutrients, such as phosphorus and nitrogen. Thus, livestock could be used to manage algal blooms, including toxic secondary metabolites, in their drinking water ponds by allowing them to walk in the ponds to increase turbidity.  相似文献   

4.
This study was conducted to biologically treat wastewater discharged from the textile industry (textiles made of cotton and/or synthetic fiber) using sequencing batch reactor (SBR) technology (activated sludge process operating on batch mode). To achieve the objectives of the study, the characteristics of textile wastewater and the biodegradation of its organic constituents under unsteady state conditions were studied. Then, a bench-scale pilot plant was used to study the performance of SBR by monitoring the settleability and change in the constituents (chemical oxygen demand and solids) over time. Results of the study showed that textile wastewater has different types of pollutants: heat, basicity, suspended solids, organic and inorganic matter, and heavy metals. The factors affecting the biodegradation of organic matter were determined as the reaction time and the ratio of initial substrate to sludge concentrations. Also, removal of solids was monitored, and the settling velocity as affected by sludge concentration was graphically presented to enable the determination of settling time. Finally, the outcome of this study was used to suggest a procedure for the design of a full-scale SBR unit for treatment of textile wastewater.  相似文献   

5.
This study was designed to: (1) evaluate dibutyltin (DBT) and tributyltin (TBT) bi-weekly in the water column for four months during the peak boating season (June–September, 1989) at seven stations in the Back Creek and Severn River area of Maryland waters of Chesapeake Bay; (2) compare butyltin values from the 1989 study with values obtained from a similar butyltin monitoring study conducted in 1988 (after Maryland TBT legislation) and 1986 (before Maryland TBT legislation); (3) determine the extent of TBT paint use in the Back Creek area by surveying boat owners; (4) determine dissolved copper concentrations from three of the seven stations bi-weekly during the four-month study; and (5) compare dissolved copper concentrations at these stations with previous copper data collected in 1988.Mean four-month DBT concentrations ranged from 10 to 73 ng/L at the seven stations. Highest DBT concentrations occurred at Station 1 in a marina; lowest concentrations occurred at Station 7 in the Severn River. Mean four-month TBT concentrations ranged from 177 ng/L at Station 1 (marina) to 21 ng/L at Station 7 (Severn River). Maximum TBT concentrations of 361 and 570 ng/L occurred at marina SDtations 1 and 3, respectively. Temporal trends in both DBT and TBT (station mean concentrations by date) showed that peak concentrations occurred during the early part of the boating season followed by reductions in late summer and early fall. Spike concentrations of both DBT (117 and 62 ng/L) and TBT (308 and 366 ng/L) were reported on two sampling dates near a boat maintenance facility in Back Creek.There was a significant reduction in DBT concentrations from 1986 to 1989 when date was treated as a fixed effect. However, TBT concentrations were not significantly reduced between 1986 and 1989 when mean concentrations of TBT were averaged across stations and dates for each year. A significant reduction was reported at Station 1 (marina station) when each station was examined for differences between years. TBT was also reported to significantly decrease (p=0.0442) at Station 7 between 1988 and 1989. A boat owner survey in the study area showed that 6% of the recreational boats that were surveyed were painted with TBT paint in 1989. This was a significant decrease in TBT paint use from the previous year when 31% of recreational boat owners surveyed used TBT paints.An evaluation of dissolved copper concentrations at three stations in the study area in 1989 showed that mean concentrations from bi-weekly sampling for four months was 10 g/L at Station 1, 7.8 g/L at Station 4 and 2.7 g/L at Station 7. Copper concentrations decreased with distance away from the Back Creek marinas. Copper concentrations at all three stations were significantly lower in 1989 than in 1988.  相似文献   

6.
The goal of this work was to identify the sources of copper loads in surface urban waters using principal component analysis under the aquatic parameters data evaluation approach. Water samples from the Irai and Iguacu rivers were collected monthly during a 12-month period at two points located upstream and downstream of a metropolitan region. pH, total alkalinity, dissolved chloride, total suspended solids, dissolved organic matter, total recoverable copper, temperature, and precipitation data provided some reliable information concerning the characteristics and water quality of both rivers. Principal component analysis indicated seasonal and spatial effects on copper concentration and loads in both environments. During the rainy season, non-point sources such as urban run-off are believed to be the major source of copper in both cases. In contrast, during the lower precipitation period, the discharge of raw sewage seems to be the primary source of copper to the Iguacu River, which also exhibited higher total metal concentrations.  相似文献   

7.
浙江近岸海域春季表层溶解氧饱和度分布及影响因素   总被引:1,自引:0,他引:1  
根据2014年春季对浙江省近岸海域溶解氧的调查结果,结合现场的温度和盐度,得出溶解氧饱和度的平面分布,并在此基础上探讨了饱和度与温度、盐度、化学需氧量、浮游植物丰度之间的关系。结果显示,浙江省近岸海域溶解氧饱和度范围为92.1%~120%,均值为100%。总体呈西部沿岸低,东部外海高的平面分布趋势。溶解氧饱和度高值区与浮游植物丰度的高值区一致。低饱和区域化学需氧量含量基本高于1 mg/L。陆源径流和有机物质耗氧分解是沿岸低饱和区域主要控制因素,外海水和浮游植物光合作用是高饱和区域主要控制因素。径流和外海水对有机物质分解和浮游植物光合作用有一定的调控作用。  相似文献   

8.
The background levels, variability, partitioning and transport of eleven trace elements-Ag, Al, As, Cd, Co, Cr, Cu, Mn, Pb, Zn and U-were investigated in a mountain range river system (Adour River, France). This particular river system displayed a turbulent hydrodynamic regime, characterized by flash-transient discharge conditions leading to fast shifts in suspended particulate matter (SPM) concentrations as high as two orders of magnitude (12 to 600 mg l(-1)). The distribution of SPM was accurately predicted with a "hysteresis" transport model, indicating that about 75% of the annual solids load was exported within 20 to 40 days. Dissolved and particulate concentrations of most trace elements were low compared to their concentrations in other reference river systems expect for Pb and Cr, associated with historical anthropogenic activities. Although dissolved and particulate metal concentrations were steady for most elements during low and average discharge conditions, significant changes were observed with increasing river discharge. The changes in trace element concentrations in the two compartments was found to induce a partitioning anomaly referred to as the particulate concentration effect. This anomaly was significant for Cr, Mn, Pb, Zn, Cu and organic carbon (p < 0.03). The processes driving this anomaly were possibly linked to the modification and/or increase of colloidal organic and inorganic vectors, suggested by the significant increase of DOC (p < 0.001) and dissolved Al concentrations (p < 0.05) during flood conditions. A complementary process linked to the influence of coarse particles of low complexation capacity and transported mainly during high discharge may also effect trace element concentrations. Annual metal fluxes transported by this river system were estimated using the hysteresis SPM model with consideration of these fate processes. Metals in the Adour River system are primarily exported into the Bay of Biscay (Atlantic Ocean).  相似文献   

9.
Water samples, drawn from groundwater monitoring wells located southeast of Oklahoma City, OK, were found to contain elevated concentrations of total chromium with an apparent source localized to the area surrounding each well. Since these monitoring wells are located in areas with no historic chromium usage, industrial sources of chromium were ruled out. Water testing was performed on twelve monitoring wells in the area that historically had elevated total chromium concentrations ranging from 10-4900 micrograms per litre. Filtered water samples were found to be free of chromium contamination, indicating that the source of the chromium is the suspended solids. Analysis of these solids by acid digestion and a sequential extraction technique revealed that the chromium was primarily associated with iron-containing solids. X-ray diffraction identified goethite, an iron oxide hydroxide, as the dominant iron-containing phase in the suspended solids. The mineralogy in this region is dominated by interbedded red-bed sandstone and mudstone whose mineral content includes mixed-layer illite-smectite, hematite, goethite, gypsum and dolomite. Elemental analysis of soil samples collected as a function of depth in the locale of the monitoring wells indicated that the iron rich clays contain a natural source of chromium. The elevated levels of total chromium are most likely due to the dissolution of silica and alumina from the chromium containing iron clays in the basic well water, resulting in the release of fine suspended solids that naturally have high chromium concentrations. These results should be applicable to other areas containing iron-rich clays.  相似文献   

10.
Sediment and suspended particulate matter samples from 24 stations in the Gulf of Kavala have been examined for lead contamination. Grain size analysis and organic matter content were also performed. Total – anthropogenic sediment lead concentrations and enrichment factors at stations close to harbors and chemical industries were found higher (up to 209–135μg/g and 4.12 respectively), in relation to concentrations from the rest of the coastal zone. In the above areas, increased suspended particulate lead in the bottom of the water column was also recorded (up to 109μg/g). Total sediment lead concentrations composed of high natural Pb background increased with decreasing grain size, suggesting their association with the fine fractions of the sediments (31.1–66.0% mud presence) and the organic matter content (6–9% higher values). Overall, higher total lead concentrations in the sediments, determined by this work, appear to be significantly different from those reported for the Gulf of Kavala in previous studies and similar to those detected in other highly contaminated eastern Mediterranean coastal areas.  相似文献   

11.
结合实验研究了水中苯胺类化合物的测定难点和影响因素,包括样品保存和水样中悬浮物的影响。苯胺类化合物易被氧化,样品不易保存且受悬浮物的影响。研究结果表明:样品中未加入抗氧化剂进行保存时,部分苯胺类化合物迅速降解;当样品中加入80 mg/L硫代硫酸钠进行保存时,部分苯胺类化合物的保存时间可以延迟2~3 d后降解。样品中悬浮物对联苯胺萃取影响较大,回收率偏低,可以通过调节样品pH至酸性后过滤,再将滤液调至中性后进行萃取,回收率明显提高。笔者同时讨论了消除与补偿基质干扰的方法,包括色谱分离条件和检测器条件的选择、优化,内标法、空白基质匹配标准校正法和工作曲线法等定量方法的选择。  相似文献   

12.
Numerous studies have demonstrated that anaerobic packed-bed reactors (APBRs) containing media such as clay chip, small stone, and porous plastic modules are effective for treating a variety of organic wastes. Most of these studies focused on the treatment capabilities of the processes, yet little work was done about the factors affecting their designs and performance. This paper presents the results of a study on a laboratory scale APBR system examining the significance of media factors such as media roughness, specific surface area, porosity and pore size on treatment performance. The results showed that media roughness and pore size were more important over surface area on the reactor performance. Within the same media porosity, pore size plays a more significant role than surface area in term of COD removal efficiency. The study indicates that the ability of a support medium to retain biomass either as suspended growth entrapped in the void space, or by attachment to the media surface is a significant consideration in an upflow APBR. A testing protocol for measuring methane gas produced by the suspended biomass using a batch serum bottle technique was developed and presented in this study. The method involved measurements of hourly methane production and instantaneous TOC concentration from the suspended biological solids extracted from various reactor heights. The proportion of methane production associated with the suspended biomass was as high as 58% at organic loading rate of 16 g COD/L.day. The results suggest that media pore size and porosity play a significant role in the performance of upflow APBRs.  相似文献   

13.
Water samples were collected in the Pearl River Estuary in July 2002 and April 2003. The particulate and dissolved phase polycyclic aromatic hydrocarbons (PAHs) were determined. Total PAH concentrations in water samples were higher in April of 2003 (C (p): 4.0-39.1 ng/L or 445.1-1,089.9 ng/g; C (w): 15.9-184.2 ng/L) than in July of 2002 (C (p): 2.6-26.6 ng/L or 297.7-1,336.6 ng/g; C (w): 12.9-28.3 ng/L). It was found that 5, 6-ring PAHs enrich in the inner estuary samples and so did 3-ring PAHs in the July samples. Compositional differences in the suspended particulate matter (SPM) might be responsible for this observation. The partition coefficient (K (p)) increased with the increasing of the particular organic carbon content of suspended particles as well as the salinity of water, decreased with the increase of the total suspended particles content of samples. A linear correlation between logK (OC) and logK (OW) was found in two sampling periods. The observed values of logK (OC) exceed their predicted values derived form linear free energy relationship between logK (oc) and logK (ow), which could be attributed to the nonlinear sorption of soot-like carbons in suspended particles.  相似文献   

14.
The Bay of Gokova in Southeastern Aegean Sea (Turkey) is important by the potential of agricultural, municipal, and tourism activities. In addition, there is no industrial plant within the area in the Aegean Sea. Kad?n Creek (Azmak) and Ak?ap?nar Creek (Azmak) flowing into the inner Gokova Bay are one of the important factors in determining the character of the inner Gokova Bay. In this study, nine stations were selected in the inner Gokova Bay, Kad?n Creek, and Akcap?nar Creek. The concentrations of Cd, Cu, Fe, Pb, and Zn were measured in suspended particulate matter (SPM) and sediments. The samples of sediments and SPM were collected in between February 2008 and September 2008. The aim of the study is searching the change of concentrations of Cd, Cu, Fe, Pb, and Zn in suspended particulate matter and sediments in the inner Gokova bay, Kad?n Creek, and Ak?ap?nar Creek. It has been identified that the metal concentrations in the creeks are higher than the metal concentrations in the marine environment. It has also been observed that the concentrations of Pb, Cd, and Cu in summer season have been higher than in the winter season, but the concentrations of Fe and Zn have not shown a significant difference between in summer and winter seasons. The obtained results show that the some heavy metals are caused by the agricultural, municipal, and tourism activities operating in the coastal areas and terrestrial environment, and they are transported from the creeks to the Gokova Bay by suspended particulate matter.  相似文献   

15.
七虎林河源头区地表腐殖质随着径流的冲刷进入水体,形成了天然有机质(NOM),其中,溶解性有机质(DOM)易对河流水质造成影响。为了研究七虎林河中DOM的时空分布特征及其对水质的影响,开展了6次采样,分析了水体及土壤吸收光谱和荧光光谱特征参数,利用平行因子(PARAFAC)算法解析了水体DOM的特性及来源。结果表明:七虎林河上游水体五日生化需氧量(BOD5)、高锰酸盐指数(CODMn)、化学需氧量(COD)、可溶性有机碳(DOC)的浓度分别为1.4 mg/L±0.2 mg/L、6.1 mg/L±3.0 mg/L、21 mg/L±8 mg/L、7.0 mg/L±3.2 mg/L,BOD5/COD平均值为0.08,说明流域内水体DOM的可生化性差,对水质影响较小。光谱特征参数紫外吸收系数(SUVA254)、荧光指数(FI)、腐殖化指数(HIX)、生物源指数(BIX)分析结果表明,七虎林河上游云山水库库上林区河段DOM的物质组成与水库及库下河段差异显著。库上河段DOM的芳香碳含量更高、分子量更大、自生源组分...  相似文献   

16.
In the aquatic environment, the accumulation of chemicalcontaminants by sediments poses a potential threat to endemiclife forms and drinking water resources. Trace metals such asCd, Cu, Cr, Ni, Pb, and toxic organic compounds, are among awide variety of contaminants having an affinity for sediments.In this study, experiments were performed simulating sedimentresuspension in the lower Housatonic River, Connecticut, using aParticle Entrainment Simulator. Analyses of grain sizedistributions, porosities and total organic contents of thesediments suggested that these parameters influence theredistribution and entrainment of settleable solids in the watercolumn. These findings were established by evaluating the impactof one parameter on sediment resuspension as a function ofstream flow with the other two characteristics being heldconstant. Total suspended solids and volatile suspended solidsresuspension concentration ranged from 3.2 to 20648.3 mg L-1,and 1.5 to 1823.8 mg L-1, respectively, with subsequentincreases in flow rates from 9 to 6 dynes cm-2. The resuspension concentrations were augmentedby sediment porosity (22.0 to 57.5%), percent finer grain-size distributions at 0.1 mm, and total organic content (2.7 g kg-1 to 29.0 g kg-1). Using K p values, and the dissolvedcontaminant levels of various trace metals, the particulatecontaminant levels of the metals were determined under variousoscillation rates. As sediment resuspension increased withincreased stream flow, there was an overall general increasefrom 0.02 to 33.6 g L-1 in the particulatecontaminant levels of Cd, Cu, Cr, Ni and Pb.  相似文献   

17.
Concentrations of heavy metals (Cu, Zn, Cd, and Pb) in surface water (including total recoverable, dissolved, suspended solids) and in aufwuchs encrusted on Moerella iridescens Benson from seven selected sites and two reference sites in Maluan Bay were investigated in order to understand current metal contamination due to industrialization and urbanization in Xiamen, China. The muscle tissues of the study species (Penceus penicillatus, Scylla serrata Forskal, Harengula zunasi Bleeker, Tillapia nilotica) from a trawling area within Maluan Bay were also analyzed in order to evaluate its safety as seafood. Based on the obtained data, metal concentrations in surface water were compared with Marine Seawater Quality Standards of China and the US EPA acute and chronic criteria, which showed that Maluan Bay may be subjected to different levels of contamination by the metals. Metal concentrations under study in the edible parts (muscle) of the investigated biota species were within the safety permissible levels for human consumption. Through Pearson??s correlation analysis, the relationships between metal concentrations in surface water and in M. iridescens were evaluated. Copper concentrations in M. iridescens were more strongly positively correlated with particulate copper in suspended solids and total recoverable copper in water rather than with dissolved copper at the sampling sites. The data suggested that copper-rich suspended solids contributed substantially to copper accumulation by M. iridescens and played a critical role in the pathway of copper into the food chain. The conclusions of this investigation are likely to be applicable to other relevant scenarios.  相似文献   

18.
Total mercury (T-Hg) concentrations in rivers are described across a rural to urban/industrial and agricultural landscape gradient in NW England. T-Hg ranges between 0.2 and 230 ng L(-1). The regional median was 3.6 ng L(-1) with individual river medians ranging between 1.9 and 8.3 ng L(-1). Median T-Hg concentrations were sometimes moderately higher for the lowland areas and at higher flows. Our estimates suggest that the Ribble estuary receives 9.2 kg y(-1) and the Wyre estuary 0.7 kg y(-1). In order to examine regional inputs from urban/industrial components, regression analysis was undertaken by comparing three types of hydrochemical signature: suspended sediments (SS), which provide a measure of the particulate component, dissolved organic carbon (DOC) that provides an indication of humic/fulvic acids that are part of the organic colloids and strong chelating agents, and boron a marker of sewage effluents and population density. The results show high positive relationships of T-Hg with both SS and DOC, but no relationship with the urban/industrial signal. The regression analysis with T-Hg indicated on average a gradient of 0.33 ng mg(-1) for DOC and 0.2 ng mg(-1) for SS. They indicate the primary importance of a diffuse source of T-Hg. For the upland areas and cleaner river systems, the linkages between T-Hg and DOC were particularly strong, while for the lowland areas, the linkage with SS proved stronger. Analysis of a latter subset of data that partition the SS into organic and inorganic fractions indicated that the T-Hg was primarily linked with the organic fraction. Indeed, multiple regression of T-Hg with DOC and POM reveals gradients similar to other parts of the World.  相似文献   

19.
Hierakonpolis, Greek for City of the Hawk, nearly 25 km NW of Idfu (Egypt), is an important and extensive archaeological discovery covering a large area. Its richness in archaeological artifacts makes it a valuable site. It has a valid claim to be the first nation state, as indicated by the Palette of Narmer discovered in its main mound. Geological and hydrogeological investigations at the Hierakonpolis Temple Town site documented nearly a 4.0-m water table rise from as early as 1892 to the present. In addition to the rising water levels, the increase of both subsoil water salinity and humidity threatens and damages fragile carvings and paintings within tombs in Kingdom Hill, the foundation stability of the site, and the known and still to be discovered artifact that recent pottery finds dates at least 4,000 BCE. Representative rock and soil samples obtained from drilled cores in the study area were chosen for conducting detailed grain size and X-ray analysis, light and heavy mineral occurrences, distribution of moisture and total organic matter, and scanning electron microscopy investigations. Mineralogical analysis of clays indicated that the soil samples are composed of smectite/illite mixed layers with varying proportions of smectite to illite. Kaolinite is the second dominant clay constituent, besides occasional chlorite. Swelling of the clay portion of the soil, due to the presence of capillary groundwater, in contact with buried mudbrick walls expands and causes severe damage to important exposed and buried mudbrick structures, including the massive ancient “fort” believed to date from the Second Dynasty (from 2,890 to 2,686 BC). The “fort” is 1.0 km south of the Temple Town mounds near to confluence of Wadi Abu Sufian. Groundwater samples from the shallow aquifer close by the intersection of Wadi Abu Sufian and the Nile flood plain were analyzed for chemical composition and stable isotope ratios. The groundwater in the upper zone (subsoil water) within fine-grained Nile alluvium is characterized by high salinity which varies from 415 to 4,500 mg/L total dissolved solids. In contrast, most of the groundwater samples in the lower zone (Quaternary aquifer) are characterized by a low salinity in the order of 164–792 mg/L. Values of δD and δO18 obtained from this deep (9–20 m) aquifer ranged from 16.98 to 19.87?‰ and from 1.67 to 2.99?‰, respectively. These values indicated that the Quaternary aquifer waters are recharged directly from recent Nile water. Subsoil water is very shallow in the area; it ranged from 0 to 2.6 m with a mean of 1.1 m within the main mound of the Hierakonpolis Temple Town site by 2003, in contrast to its more than 4.5-m depth in 1897. The exposure of subsoil water to increased evaporation is expected, with a consequent increase in the concentrations of dissolved solids and usually large proportions of chloride and sulfate. Artifacts recovered from the Temple Town site are becoming damaged and destroyed by crystallization processes caused by repeated wetting and drying of salt and the accumulation of new salts.  相似文献   

20.
以污水厂长序列运行数据为基础,反推脱氮实际影响因素,开展反硝化脱氮试验。结果表明,在2019年4月前后TN出水平均浓度降低58%;受季节和污水厂升级改造影响,温度由15℃升高至25℃,混合液悬浮固体质量浓度(MLSS)由4300 mg/L增至8000 mg/L,活性污泥成分增加,脱氮效果提升;BOD 5/TN和pH值等变化相对稳定,温度、MLSS是影响该污水处理厂反硝化脱氮的主要因素;当反应温度为(25±5)℃,pH值为7.5±0.2,MLSS为4800 mg/L时,反硝化脱氮效果最佳,硝酸盐氮去除率达91%。  相似文献   

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