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1.
Chrome electroplating wastes were collected from two industrial sites and analyzed for color, turbidity, pH, alkalinity, sulfate, chloride, N-ammonia, N-nitrate, N-nitrite, acid hydrolyzable P, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, chromate and chromium(VI). The effect of these wastes on saprophytic and nitrifying bacteria was studied with varying concentrations of the waste using sucrose substrate as a source of C chain for microorganisms. The use of clay sand mixtures as adsorbents for chromate and chromium(VI) was investigated. Mixtures high in clay content were found to be suitable media for the removal of Cr from the wastes. The clay used was characterized by determination of the following parameters: pH, electrical conductivity, water soluble salts, osmotic pressure, cation exchange capacity, CaCO3 and organic matter.  相似文献   

2.
The aim of this study was to investigate the seasonal and spatial variations in surface water quality at the mid-Black Sea coast of Turkey. The samples were collected from ten monitoring stations including rivers and sea water during the years from 2007 to 2008. The samples were analyzed for 25 parameters: total carbon, total inorganic carbon, total organic carbon, chromium, cadmium, copper, lead, iron, nickel, manganese, phenol, surfactants, ammonium, nitrite and nitrate-nitrogen, total phosphorus, adsorbable organic halogen, sulfate, hardness, dissolved oxygen, pH, temperature, total dissolved solids, electrical conductivity, and salinity. Multivariate statistical techniques, cluster analysis (CA) and factor analysis/principal component analysis (FA/PCA), were applied to analyze the similarities among the sampling sites to identify the source apportionment of pollution parameters in surface waters. The results indicate that seven factors for river water explained 82.24% of the variance. In seawater, seven factors account for 89.65% of the total variance. Varifactors obtained from factor analysis indicate that the parameters responsible for water quality variations are mainly related to organic pollution (municipal effluents), inorganic pollution (industrial effluents and waste disposal areas), nutrients (agricultural runoff), and dissolved salts (soil leaching and runoff process).  相似文献   

3.
The speciation of mercury (Hg) in Minamata Bay (Japan) was studied over a 2-year period (2006?C2008). Concentrations of dissolved total Hg, dissolved methylmercury (MeHg), particulate total Hg, and suspended solids were 0.43?±?0.14 ng/l (mean?±?standard deviation), 0.10?±?0.06 ng/l, 3.04?±?2.96 ng/l, and 5.94?±?2.10 mg/l, respectively. Correlations between concentrations of particulate total Hg and suspended solids at four depths (surface: 0 m; mid-depth: ?6 m, ?10 m; and bottom +1 m layer) were only significant in the bottom +1 m layer. The mean dissolved MeHg concentration and the ratio of dissolved MeHg to dissolved total Hg were considerably higher in summer compared to other seasons. The data suggest that bottom sediment was not the sole source of MeHg, and that MeHg may be produced in the water column by the conversion of divalent Hg eluted from resuspended bottom sediment. The correlation between seawater characteristics such as salinity, temperature, dissolved oxygen (DO), and dissolved MeHg concentration indicates that Hg methylation could be influenced by the heterotrophic activity of microorganisms in the seawater. In particular, inverse correlations were observed between DO, salinity, and MeHg concentration. However, dissolved MeHg concentrations did not correlate with seawater characteristics such as pH or chlorophyll-a.  相似文献   

4.
Ikem  A.  Osibanjo  O.  Sridhar  M. K. C.  Sobande  A. 《Water, air, and soil pollution》2002,140(1-4):307-333
Two industrial and highly populated cities namely Ibadan and Lagos, both located in Southwestern Nigeria have urban migrationproblems and resource limitations. As a result, the development of residential areas near waste sites and the indiscriminate dumping of municipal waste are common in both cities. Orita-Aperin and Oworonsoki neighborhoods in Ibadan and Lagos,respectively, both located near a waste site were studied. The two areas relied on the wells as sources of drinking water hence poor drinking water quality may have health consequences. A totalof 51 ground-water samples (30 wells in Ibadan and 21 wells in Lagos) were monitored seasonally for two years in Ibadan and a year in Lagos. Results from this study revealed that some of theground-water quality constituents determined exceeded the World Health Organization (WHO) standards for drinking water irrespective of source of pollution. Some of the ground-water samples were poor in quality in terms of pH, conductivity, totaldissolved solids, chloride, nitrate, ammonia, COD, Al, Cd, Cr, Fe, Pb, Ni and total coliforms recorded. Thus, ground-water fromsome of these private wells requires further purification to ensure its fitness for human consumption.F-test, one-way parametric analysis of variance (ANOVA), Mann-Whitney `T' test and Kruskal-Wallis H-test applied to upgradient and downgradient concentrations suggest impact ofthe waste sites on ground-water quality. The Mann-Whitney testonly suggests that the downgradient values of Fe (Ibadan: dryseason (1), sulfate (Ibadan: rainy season (2) and pH (Lagos: dry season (2) were significant at 5% level of significance. For Ibadan wells, the Kruskal-Wallis test showed that variances ofspecific conductivity, dissolved solids, and chloride for Ibadanupgradient and downgradient values were unequal. Also variances of specific conductivity and dissolved solids for upgradient anddowngradient values in Lagos were unequal at 5% level of significance. Three downgradient wells in Lagos and four downgradient wells in Ibadan had significant impact due to leachate migration into drinking wells.  相似文献   

5.
Constructed wetlands have recently received considerable attention as low cost and efficient means of cleaning up many different types of wastewaters at secondary and tertiary levels. This is an environmentally sound method of wastewater treatment that does not use hazardous chemicals, and is based on the high productivity and nutrient removal capability of the wetland that strongly relies on its intricate ecosystem structure and function. Research work was conducted on a tropical constructed wetland to establish its capability to treat wastewater during the dry season. A comparison of its efficacy with that of conventional wastewater treatment plants was made on the basis of the measured water quality parameters. Temperature, pH, dissolved oxygen, and conductivity were measured in situ. Total suspended solids (TSS), total dissolved solids (TDS), biochemical oxygen demand (BOD5), chemical oxygen demand (COD), phosphorus, ammonia, and nitrites were analyzed in the laboratory. Fecal coliforms were enumerated and Escherichia coli counts were determined. The TSS values reduced from a mean of 102 mg/l at the influent point to 16 mg/l at the effluent point, depicting a reduction of 84.3%. Influent TDS averaged 847 mg/l, while the effluent averaged 783 mg/l. Dry season BOD5 levels were reduced from an average of 286 at the inlet point to 11 mg/l at the outlet representing a reduction efficiency of 96.2%. COD levels were reduced from a mean of 2,002.5 to 47.5 mg/l depicting a removal efficiency of 97.6%. Phosphorus was reduced from a mean of 14 to 11 mg/l representing a percentage removal of 21.4%. Levels of ammonia reduced from a mean of 61 at the influent point to 36 mg/l at the effluent point representing a percent reduction of 41.0%. There was a 99.99% reduction for both the fecal coliforms and E. coli counts. Conductivity of wastewater increased from 1.08 to 1.98 mS, while the pH increased from 6.23 at the inlet point to 7.99 at the outlet of the system. Temperature and dissolved oxygen measurements showed a diurnal variation. The dry season wastewater heavy metal concentrations were in the following ranges: Pb (0.7?C6.9 ppm), Cr (0.2?C0.5 ppm), Zn (0.1?C2.3 ppm), Ni (0.1?C1.3 ppm) with Cd and Cu not being detected in the wastewater streams. Overall, tropical constructed wetlands are effective in treating wastewater streams and they perform a lot better than the popularly used waste stabilization ponds. This paper recommends that they can be widely used within the tropics.  相似文献   

6.
Studies of waste generation from the freshwater phase of Atlantic salmon (Salmo salar L.) production have not been substantially updated since the mid 1980's, and advances in husbandry prectices designed to reduce wastage which have taken place in that period therefore remain unconsidered. In order to determine if reductions have been achieved, two Scottish fish farms were visited on a number of occasions during one year, and outputs of suspended solids (SS), biochemical oxygen demand (BOD), total ammonia nitrogen (TAN) (NH3+NH4 +), dissolved reactive and total phosphorus (DRP, TP) were monitored. The range of waste loadings obtained were 9.1–10.0 kg TP t fish?2 yr?1, 410 kg BOD5 t fish?1 yr?1, 191–606 kg SS t fish?1 y?1, and 20.3–39.3 kg TAN-N t fish?1 yr?1. Compared to existing data, a greater range of daily waste loadings were observed, suggesting that more frequent monitoring is required to reduce variations observed in the data set, and to obtain accurate information on waste outputs from such operations. Modifications of feeding methods remains a route through which further reductions in waste outputs may be made.  相似文献   

7.
Effluents from petroleum refineries contain a diverse range of pollutants including heavy metals. They also contain oil and grease, phenols, sulphides, dissolved solids, suspended solids and BOD-bearing materials. An overview of heavy metal removal from industrial effluents with emphasis on biological methods is given. Results of studies to remove heavy metals in effluents from a petroleum refinery by water hyacinth were presented. Limited success has been demonstrated for the case of iron and zinc, but further work needs to be done. There is a need to strike the right balance between the possible amount of uptake of heavy metal ions and the tendency to suffocate the ecosystem through the depletion and reduction of light and dissolved oxygen. Similarly there is a need for better understanding of the process of enhancement of the capability the water hyacinth to uptake heavy metal ions before the on-set of toxic accumulation.  相似文献   

8.
The River. Mersey and its Estuary is assessed for the effects of pollution by using biological indicators; a sampling program for certain bacteria indicates that there is often gross pollution, although there is a wide range of observed values on both short time and space scales. This study considers bacteriological contamination in order to supplement existing survey data on heavy metals, dissolved oxygen, biochemical oxygen demand and suspended solids.  相似文献   

9.
Increase in alfalfa (Medicago sativa L.) production for energy (gasification of stems) and protein supplement (from leaves) has been proposed for the upper Midwestern United States, an area where corn (Zea mays L.) in rotation with soybean (Glycine max L.) is the predominant crop sequence. This study was undertaken to assess the impact on runoff and water quality, especially for the loss of oxygen demanding material with snowmelt. Four field size watersheds were instrumented at Morris, Minnesota, USA on a rolling prairie landscape. Snowmelt runoff from each watershed was measured with two flumes with overlapping ranges arranged in series. An automatic water sampler collected runoff samples for chemical analysis. Oxygen demand was used as a surrogate for reduced carbon. Water samples were analyzed for total solids, biochemical oxygen demand (BOD), and chemical oxygen demand (COD). Based on the results of snowmelt events of 1997, 1998, and 1999, the alfalfa fields yielded more runoff than corn-soybean fields. The loss of total solids was more consistent from alfalfa fields. Total solids losses interacted with crop and year. Compared to alfalfa fields losses were less following soybeans and greater following corn. On average losses were similar between alfalfa and corn-soybean fields. Runoff from alfalfa fields contained about four times more BOD than corn-soybean fields. Although not statistically significant due to only two replications, there was a similar trend for COD. This study shows that although losses of total solids in snowmelt from alfalfa fields was similar to corn-soybean fields, there can be increased losses of oxygen demanding materials.  相似文献   

10.
Compost stability was quantified using dissolved oxygen (D. O.) respirometry during composting of municipal solid waste (MSW) in a pilot-scale system. Changes in stability of samples taken at various times during the composting process were verified with chemical and physical tests. Rates of change of oxygen level in air over a compost sample incubated in a flask at 37°C were converted to a rate of O2 uptake/(g volatile solids · hour). Oxygen uptake, determined with D. O. respirometry and converted to rates of dry matter loss, was correlated with actual rates, calculated from energy balances observed in the pilot-scale system. The method can be used either as a simple quality control measure or in a more complex way to calculate rates so that efficiency within or among composting facilities can be compared.  相似文献   

11.
Major cations [calcium (Ca), magnesium (Mg), sodium (Na), potassium (K)], anions [nitrite (NO2), nitrate (NO3), choride (Cl), sulfate (SO4)], dissolved copper (Cu) and zinc (Zn), total nitrogen (TN), dissolved phosphorous (DP), total phosphorus (TP), suspended solids (SS), chemical oxygen demand (COD), dissolved organic carbon (DOC), and O2 were analyzed in a small stream draining an agroforestry catchment located in northwest Spain. The mean concentrations found were relatively low compared to global “average” values. The results are consistent with the low population density and the nonintensive agriculture developed in the catchment. The nutrient balance offers relatively low loss rates for nitrogen (N) and phosphorus (P) (14.6% and 1.8%, respectively), although losses could have been underestimated by the use of regular sampling. Moreover, soil analysis reveals a possible P accumulation in cultivated fields of the catchment. Correlation analysis shows that components with a greater presence in fertilizers have generally positive correlations between them and with flow values. On the other hand, major ions show a negative correlation with discharge levels because their main sources have a geological origin.  相似文献   

12.
Physical and chemical constituents of the Missouri River near Brownville, Neb. U.S.A. were studied during the period May, 1970 through December, 1972. Considerable variation in river discharge was observed. The changing hydrological conditions affected the concentrations of both the dissolved and suspended constituents in the river. Rain and snowmelt runoff increased the river discharge and also contributed to increased turbidity and total suspended solids. A number of parameters including total phosphorus, total organic nitrogen, oxygen demand and certain metals correlated with increased suspended solids. However, most of the major anions and cations measured showed decreased concentrations as a result of increased river discharge.  相似文献   

13.
Spatial and temporal variations of eight selected water quality measurements were examined for the 26 stations located in the Han River and its tributaries within the city of Seoul from 1993 to 2002. The eight measurements are water temperature, pH, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, suspended solid, total nitrogen and total phosphorus. There is no discernable increase or decrease in water quality measurements in four representative stations. A striking longitudinal variation of all water quality measurements is detected for eight stations along the Han River. Water quality dramatically decline in the middle section of the Han River where the river receives inputs from polluted tributaries. All water quality measurements, except pH, exhibit better conditions in the main river group than its counterpart tributary group. The 26 stations can be grouped into three main clusters; (1) the main river and its tributaries that have relatively good water quality, (2) the tributaries that have medium water quality, and (3) the tributaries nearby industrial sites that are heavily polluted.  相似文献   

14.
This study evaluated the impacts of three sugarcane residue management techniques, namely postharvest burning of residue (BR), shredding of residue (SR), and full postharvest retention of residue (RR), on the water quality of surface runoff from February 2006 to September 2007 in Iberia, LA. Total runoff volumes recorded were 58,418, 57,923, and 46,578 L for the BR, SR, and RR treatments, respectively. Except for total Kjeldahl nitrogen (TKN), which was higher for BR than RR or SR, there were no significant differences in total loads of total suspended solids (TSS), total dissolved solids (TDS), biological oxygen demand at 5 days (BOD5), total phosphorus (TP), nitrate-N, nitrite-N, and sulfate among the three residue management techniques, although the RR treatment generally exported the lowest total loads. Regression analyses on the pollutant load and rainfall event showed that the load exported for each water quality parameter was positively correlated with precipitation, with the BR treatment being more sensitive to rainfall amount than the RR and SR treatments in TSS, TKN, TP, BOD, nitrate, and sulfate exports. Runoff TSS and turbidity were also highly correlated (R 2?=?0.95, P?<?0.001). The results suggested that the two sugarcane residue retention practices (RR and SR) had limited benefit on improving surface runoff water quality over the BR practice in subtropical region such as Louisiana.  相似文献   

15.
该文对基于复合垂直流人工湿地(IVCW)的循环水养殖系统的净化效率、养殖效果和系统优化设计进行了研究.结果表明,在420 mm/d的水力负荷下,湿地可有效地去除循环水中的总悬浮物(去除率85%)、CODCr(去除率50%)、BOD5(去除率44%)、总氨氮(去除率53%)、亚硝酸盐(去除率83%)和硝酸盐(去除率54%),能够满足养殖用水的要求,整个试验期间系统实现了零污水排放.经过5个月的养殖,成功地将斑点叉尾鲴(Ictalurus punctatus)鱼苗(1.8 cm,0.08g)培育成鱼种(15.9 cm,33.9 g),成活率达到92.6%.在养殖容量、病害控制、成活率以及鱼体生长速度等方面均优于常规池塘养殖模式.建立了一个预测湿地与养殖池塘面积配比的数学模型,为实际应用和优化设计提供依据.  相似文献   

16.
This paper reports a fully automatic respirometric technique with low maintenance costs that allows the routine determination of the specific oxygen uptake rate (SOUR), as well as the cumulative oxygen demand at 20 h, (OD20). The procedure involves the measurement of the dissolved oxygen concentration in an aqueous suspension of compost that is supplied with various nutrients, none of which contains organic carbon. The proposed method was used to monitor composting in a compost pile consisting of 65% organic matter obtained by selective collection of municipal solid waste (MSW), 30% sewage sludge and 5% plant trimming residues. Based on the results, the maximum SOUR value reached, (SOURmax), decreases gradually with time, to values near 1 mgO2/gVS.h after 130 days; indicating that the final product is stable. Linear correlations between OD20 and the absorbances at 465 and 665 nm of aqueous extracts of compost, and its soluble chemical organic demand (CODsol), and soluble organic carbon (TOCsol) are significant at the p ≤ 0.01 level. However, the use of such variables instead of respirometric data requires prior experimentation with the type of waste to be composted in order to identify the absolute values at which biological activity ceases.  相似文献   

17.
This work develops a system dynamic simulation model for free-water surface constructed wetlands, as well as provides appropriate values for the parameters of constructed wetland management. The system dynamic model is calibrated and validated by using data from a 1-year study of a constructed wetland in Tainan of southern Taiwan. Additionally, the major parameters that affect the simulation output are obtained via sensitivity analysis by using generalized likelihood uncertainty estimation (GLUE). A high R 2 and Nash?CSutcliffe coefficient of efficiency between the simulated and measured outflow values indicate that in addition to reproducing the changing trends of dissolved oxygen (DO), 5-day biological oxygen demand (BOD5), total nitrogen (TN), total suspended sediment (TSS), and total phosphorous (TP) concentrations, the model can simulate the variations of DO, BOD5, and TSS. Taken into account the interactions among parameters, the GLUE method successfully obtained the model sensitive parameters from the Monte Carlo parameter sets. Sensitivity analysis results indicate that the parameters of microorganisms are sensitive factors that affect DO, BOD5, and TN, while sediment diameter largely influences TP and TSS. Further elucidating environmental microorganisms would increase the model accuracy and provide a valuable reference for constructed wetland management and design.  相似文献   

18.

Purpose

Discharge of untreated domestic and industrial waste in many European rivers resulted in low oxygen concentrations and contamination with trace metals, often concentrated in sediments. Under these anoxic conditions, the formation of insoluble metal sulfides is known to reduce metal availability. Nowadays, implementation of waste water treatment plants results in increasing surface water oxygen concentrations. Under these conditions, sediments can be turned from a trace metal sink into a trace metal source.

Materials and methods

In an ex situ experiment with metal contaminated sediment, we investigated the effect of surface water aeration on sediment metal sulfide (acid volatile sulfides (AVS)) concentrations and sediment metal release to the surface water. These results were compared with long-term field data, where surface water oxygen and metal concentrations, before and after the implementation of a waste water treatment plant, were compared.

Results and discussion

Aeration of surface water in the experimental setup resulted in a decrease of sediment AVS concentrations due to sulfide oxidation. Metals, known to precipitate with these sulfides, became more mobile and increasing dissolved metal (arsenic (As), cadmium (Cd), copper (Cu)) concentrations in the surface water were observed. Contrary to As, Cd, or Cu, manganese (Mn) surface water concentrations decreased in the aerated treatment. Mn ions will precipitate and accumulate in the sediment as Mn oxides under the oxic conditions. Field data, however, demonstrated a decrease of all total metal surface water concentrations with increasing oxygen concentrations following the implementation of the waste water treatment plant.

Conclusions

The gradual decrease in surface water metal concentrations in the river before the treatment started and the removal of metals in the waste water treatment process could not be countered by an increase in metal flux from the sediment as observed in the experiment.  相似文献   

19.
Biokinetic parameters for biological treatment byactivated sludge process of cassava meal processingwastewaters were investigated. The experiments werecarried out in three steps: Firstly, the flocculationand sedimentation methods were employed with aJar-test in order to change the effluent concentrationof organics from 14 000 to 2000 mg L-1 and alsoto remove suspended solids. The second step wasperformed with four PVC reactors for biokineticparameters studies. The parameters found were used insizing a reactor for biological degradation byactivated sludge process. At the end, the finaleffluent was submitted to a treatment with aluminumsalts and natural polyelectrolytes to remove fecalcoliforms, remaining turbidity, and suspended solids.The biokinetic parameters investigated were: substrateremoval rate, food to microorganisms ratio (F/M),endogenous respiration rate, oxygen utilized per mg ofCOD removed, specific growth rate, etc.  相似文献   

20.
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