This research studied a new spectrophotometric method for measuring the chemical oxygen demand （COD） of seawater. In this method, the COD was measured using a spectrophotometer instead of titrating with sodium thios...This research studied a new spectrophotometric method for measuring the chemical oxygen demand （COD） of seawater. In this method, the COD was measured using a spectrophotometer instead of titrating with sodium thiosuiphate. The measuring wavelength was selected to be 470 nm, and the COD of three standard glucose solutions （COD = 0.5, 1.5 and 2.5 mgL^-1, respectively） and two seawater samples （from the South Yellow Sea and Jiaozhou Bay） were measured using the spectrophotometric method and titrimetric method respectively. The results showed that the spectrophotometric method was somewhat better than the titrimetric method. The relative standard deviation （RSD） of the spectrophotometric method was less than 2.7%, and the recovery of seawater samples ranged from 96.3% to 103.8%. In addition, the spectrophotometric method has other advantages such as expeditiousness, operation simplicity, analysis automatization, etc. Therefore the spectrophotometric method can be used to measure the COD of seawater with satisfactory results.展开更多
Recent improvements to sewerage systems have meant that the relative contribution of point sources of pollution to the overall pollutant loads of streams has decreased markedly. Consequently, the potential increase in...Recent improvements to sewerage systems have meant that the relative contribution of point sources of pollution to the overall pollutant loads of streams has decreased markedly. Consequently, the potential increase in non-point source pollution means that it may be necessary to focus more on pollution loads from non-point sources in the future. This study examined pollution loads from non-point sources in streams flowing through forested areas. In addition, the relationship between runoff and pollution loads was also clarified. The small streams in the Tohoku University Botanical Gardens, in Sendai city, Japan, were sampled during a dry weather period and their water quality parameters were characterized. Chemical Oxygen Demand （COD） concentration increased with distance downstream, possibly because the soils in downstream areas contained high amounts of organic matter. Conversely, the concentration of nitrate nitrogen （NO3-N） decreased with distance downstream, probably because upstream soils were generally in an oxidized state while those further downstream were reduced. COD concentration increased with air temperature, while NO3-N levels decreased with an increase in air temperatures.展开更多
Laboratory research and engineering applications demonstrated that oxygen aeration can rapidly increase the level of dissolved oxygen in the water of severely polluted rivers. This method was capable of eliminating th...Laboratory research and engineering applications demonstrated that oxygen aeration can rapidly increase the level of dissolved oxygen in the water of severely polluted rivers. This method was capable of eliminating the odorous substances from black odorous water and reducing the color shade of water, but could not remove the NH3-N, COD, TP or other common pollutants. Therefore, oxygen aeration can be implemented to rapidly eliminate black odorous from rivers, lakes and reservoirs, but cannot be used as a permanent method for treating pollution of rivers.展开更多
This field study sought to determine the all-weather surface construction providing the least contaminated runoff and drainage effluent when exposed to moderate to heavy precipitation and different manure loads in hor...This field study sought to determine the all-weather surface construction providing the least contaminated runoff and drainage effluent when exposed to moderate to heavy precipitation and different manure loads in horse paddocks during wintertime. Two different combinations of non-woven and woven geotextile together with two gravel fractions of 200 nlm were exposed to precipitation and horse manure/urine for two years under two manure regimes （manure removal and manure accumulation）. In a simulated rainfall （SR） study, the test areas were also exposed to 50 mm precipitation for 30 min and 15 kg of horse manure under the two manure regimes. Runoff, drainage effluent and leachate flow were measured and sampled for both regimes. The geotextile-gravel construction reduced runoff and drained the test area throughout the two-year period, confirming construction stability and a dry walking surface area at a mean drain flow of 3.65 L m2 h1. The concentrations of total N, total phosphorus （TP）, chemical oxygen demand （COD） and total solids （TS） in fluids leaving the test areas in winter were lower than in previous studies, due to lower horse density. The mean drainage concentration of TP, COD and TS was 3.4, 231, 739 mg L1, respectively, due to manure removal in the SR study. The TP （1.9 mg L-1） concentration in drain fluids was reduced by 47% in the test area consisting of a single geotextile compared with previously reported values （3.6 mg Ll）. With the paddock designs tested here, non-point pollution from paddocks could be controlled and reduced.展开更多
River Ghataprabha, during its course through Belgaum district in Karnataka state （India）, receives untreated domestic waste from Gokak town and other neighboring villages situated on the bank of the river. The prese...River Ghataprabha, during its course through Belgaum district in Karnataka state （India）, receives untreated domestic waste from Gokak town and other neighboring villages situated on the bank of the river. The present study involves the application of water quality model QUAL2K to predict the water quality of this polluted segment of the river. The model was calibrated and validated for biochemical oxygen demand （BOD）, dissolved oxygen （DO） and total nitrogen （TN） in pre-monsoon season. Data for calibration and validation were obtained after the field and laboratory measurements. The performance of the model was evaluated using statistics based on standard errors （SE） and mean multiplicative errors （MME）. The model represented the field data quite well with some exceptions. In spite of some differences between the measured and simulated data sets at some points, the calibration and validation results are acceptable especially for the developing countries where the financial resources are often limited for frequent monitoring campaigns and higher accuracy data analysis.展开更多
The study was conducted to assess the effect of evaporation ponds of an ethanol distillery spent wash on groundwater, with a reference to heavy metal contamination. The distillery discharging 11,880 m3 spent wash per ...The study was conducted to assess the effect of evaporation ponds of an ethanol distillery spent wash on groundwater, with a reference to heavy metal contamination. The distillery discharging 11,880 m3 spent wash per day is extremely loaded with minerals and chemical oxygen demanding organic substances. The groundwater around the evaporation ponds is used for drinking and irrigation purposes. Thirty-five representative samples （three spent wash, two drainage water and 30 groundwater） were examined for 13 different parameters： pH, TDS （total dissolved solids）, COD （chemical oxygen demand）, the heavy metal Cd, Co, Cr, Cu, Fe, Mn, Ni, Zn, Pb and As concentrations. The physico-chemical parameters were found in following range pH 7.2-7.7 ＆ 6.8-7.7, TDS 24,448-28,608 mg/L ＆ 302-4,406 mg/L, COD 20,080-24,320 mg/L ＆ 0.0-53 mg/L, Cd 190-140 μg/L ＆ 1.5-8.7 μg/L, Co 1,240-1,987 μg/L ＆ 20.5-87.2 μg/L, Cr 1,020-1,330 μg/L ＆ 14.4-38.1 μg/L, Cu 5,200-6,300 μg/L ＆ 15.0-109.3 μg/L, Fe 2,910-3,242 μg/L ＆ 0-860 μg/L, Mn 49,900-59,500 μg/L ＆ 16.3-138.7 μg/L, Ni 1,430-1,760 μg/L ＆ 8.0-107.7 μg/L, Zn 3,359-5,250 μg/L ＆ 0.0-850 μg/L, Pb 8.9-9.8 μg/L ＆ BD （below detection）-8.7 μg/L, As 5.0 μg/L ＆ BD-10.0 μg/L for spent wash and groundwater samples, respectively. The drainage water samples had parameters within limits for industrial effluents. The spent wash samples contained metal ions higher than the permissible limits for industrial effluents and the samples of groundwater collected around the evaporation ponds contained higher concentrations of metal ions as compared to samples collected away from the evaporation ponds. Coefficient of correμtion among 11 parameters was calcuμted and contamination index was also determined, 33.3% of groundwater samples mostly collected around evaporation ponds had a contamination index above 3 and are considered extremely polluted.展开更多
Using the RMA4 water quality model to simulate the water quality of Neijiang river in Zhenjiang, the result showed that： in the dry season the ranges of the concentration of various pollutants simulation of Neijiang ...Using the RMA4 water quality model to simulate the water quality of Neijiang river in Zhenjiang, the result showed that： in the dry season the ranges of the concentration of various pollutants simulation of Neijiang were BOD5 3.2-5.2 mg/L, CODMn 4.7-6.8 mg/L, NH3-N 0.46-1.8 mg/L, TP 0.23-0.48 mg/L, and in the rainy period, the ranges of the concentration of various pollutants simulation of Neijiang were BOD5 0.69-0.73 mg/L, CODM, 1.9-2.3 mg/L, NH3-N 0.25-0.38 mg/L, TP 0.14-0.17 mg/L.These simulated values were closed to the monitoring values of pollution concentrations of Neijiang, which indicated that RMA4 was certain practical in the river water quality simulation, and simulation results have a certain degree of reliability, and it provides a scientific planning and management method for the river pollution control.展开更多
The BOD5-DO (Biochemical Oxygen Demand in five days and Dissolved Oxygen) are important indexes that reflect the organic pollution extent of water,but the variation of the indexes is closely related with water tempera...The BOD5-DO (Biochemical Oxygen Demand in five days and Dissolved Oxygen) are important indexes that reflect the organic pollution extent of water,but the variation of the indexes is closely related with water temperature. The study on the coupled mathematical model reflecting the BOD5-DO with temperature is the key to reveal the mechanism of the migration and distribution of BOD5-DO in the water. The authors presented 1-D mathematical model for the three variables in vertical direction,and gave accurate solution for the equations under steady state,the relation among the variables and the method for solving BOD5-DO concentrations at different depth and temperature.展开更多
文摘This research studied a new spectrophotometric method for measuring the chemical oxygen demand （COD） of seawater. In this method, the COD was measured using a spectrophotometer instead of titrating with sodium thiosuiphate. The measuring wavelength was selected to be 470 nm, and the COD of three standard glucose solutions （COD = 0.5, 1.5 and 2.5 mgL^-1, respectively） and two seawater samples （from the South Yellow Sea and Jiaozhou Bay） were measured using the spectrophotometric method and titrimetric method respectively. The results showed that the spectrophotometric method was somewhat better than the titrimetric method. The relative standard deviation （RSD） of the spectrophotometric method was less than 2.7%, and the recovery of seawater samples ranged from 96.3% to 103.8%. In addition, the spectrophotometric method has other advantages such as expeditiousness, operation simplicity, analysis automatization, etc. Therefore the spectrophotometric method can be used to measure the COD of seawater with satisfactory results.
文摘Recent improvements to sewerage systems have meant that the relative contribution of point sources of pollution to the overall pollutant loads of streams has decreased markedly. Consequently, the potential increase in non-point source pollution means that it may be necessary to focus more on pollution loads from non-point sources in the future. This study examined pollution loads from non-point sources in streams flowing through forested areas. In addition, the relationship between runoff and pollution loads was also clarified. The small streams in the Tohoku University Botanical Gardens, in Sendai city, Japan, were sampled during a dry weather period and their water quality parameters were characterized. Chemical Oxygen Demand （COD） concentration increased with distance downstream, possibly because the soils in downstream areas contained high amounts of organic matter. Conversely, the concentration of nitrate nitrogen （NO3-N） decreased with distance downstream, probably because upstream soils were generally in an oxidized state while those further downstream were reduced. COD concentration increased with air temperature, while NO3-N levels decreased with an increase in air temperatures.
文摘Laboratory research and engineering applications demonstrated that oxygen aeration can rapidly increase the level of dissolved oxygen in the water of severely polluted rivers. This method was capable of eliminating the odorous substances from black odorous water and reducing the color shade of water, but could not remove the NH3-N, COD, TP or other common pollutants. Therefore, oxygen aeration can be implemented to rapidly eliminate black odorous from rivers, lakes and reservoirs, but cannot be used as a permanent method for treating pollution of rivers.
文摘This field study sought to determine the all-weather surface construction providing the least contaminated runoff and drainage effluent when exposed to moderate to heavy precipitation and different manure loads in horse paddocks during wintertime. Two different combinations of non-woven and woven geotextile together with two gravel fractions of 200 nlm were exposed to precipitation and horse manure/urine for two years under two manure regimes （manure removal and manure accumulation）. In a simulated rainfall （SR） study, the test areas were also exposed to 50 mm precipitation for 30 min and 15 kg of horse manure under the two manure regimes. Runoff, drainage effluent and leachate flow were measured and sampled for both regimes. The geotextile-gravel construction reduced runoff and drained the test area throughout the two-year period, confirming construction stability and a dry walking surface area at a mean drain flow of 3.65 L m2 h1. The concentrations of total N, total phosphorus （TP）, chemical oxygen demand （COD） and total solids （TS） in fluids leaving the test areas in winter were lower than in previous studies, due to lower horse density. The mean drainage concentration of TP, COD and TS was 3.4, 231, 739 mg L1, respectively, due to manure removal in the SR study. The TP （1.9 mg L-1） concentration in drain fluids was reduced by 47% in the test area consisting of a single geotextile compared with previously reported values （3.6 mg Ll）. With the paddock designs tested here, non-point pollution from paddocks could be controlled and reduced.
文摘River Ghataprabha, during its course through Belgaum district in Karnataka state （India）, receives untreated domestic waste from Gokak town and other neighboring villages situated on the bank of the river. The present study involves the application of water quality model QUAL2K to predict the water quality of this polluted segment of the river. The model was calibrated and validated for biochemical oxygen demand （BOD）, dissolved oxygen （DO） and total nitrogen （TN） in pre-monsoon season. Data for calibration and validation were obtained after the field and laboratory measurements. The performance of the model was evaluated using statistics based on standard errors （SE） and mean multiplicative errors （MME）. The model represented the field data quite well with some exceptions. In spite of some differences between the measured and simulated data sets at some points, the calibration and validation results are acceptable especially for the developing countries where the financial resources are often limited for frequent monitoring campaigns and higher accuracy data analysis.
文摘The study was conducted to assess the effect of evaporation ponds of an ethanol distillery spent wash on groundwater, with a reference to heavy metal contamination. The distillery discharging 11,880 m3 spent wash per day is extremely loaded with minerals and chemical oxygen demanding organic substances. The groundwater around the evaporation ponds is used for drinking and irrigation purposes. Thirty-five representative samples （three spent wash, two drainage water and 30 groundwater） were examined for 13 different parameters： pH, TDS （total dissolved solids）, COD （chemical oxygen demand）, the heavy metal Cd, Co, Cr, Cu, Fe, Mn, Ni, Zn, Pb and As concentrations. The physico-chemical parameters were found in following range pH 7.2-7.7 ＆ 6.8-7.7, TDS 24,448-28,608 mg/L ＆ 302-4,406 mg/L, COD 20,080-24,320 mg/L ＆ 0.0-53 mg/L, Cd 190-140 μg/L ＆ 1.5-8.7 μg/L, Co 1,240-1,987 μg/L ＆ 20.5-87.2 μg/L, Cr 1,020-1,330 μg/L ＆ 14.4-38.1 μg/L, Cu 5,200-6,300 μg/L ＆ 15.0-109.3 μg/L, Fe 2,910-3,242 μg/L ＆ 0-860 μg/L, Mn 49,900-59,500 μg/L ＆ 16.3-138.7 μg/L, Ni 1,430-1,760 μg/L ＆ 8.0-107.7 μg/L, Zn 3,359-5,250 μg/L ＆ 0.0-850 μg/L, Pb 8.9-9.8 μg/L ＆ BD （below detection）-8.7 μg/L, As 5.0 μg/L ＆ BD-10.0 μg/L for spent wash and groundwater samples, respectively. The drainage water samples had parameters within limits for industrial effluents. The spent wash samples contained metal ions higher than the permissible limits for industrial effluents and the samples of groundwater collected around the evaporation ponds contained higher concentrations of metal ions as compared to samples collected away from the evaporation ponds. Coefficient of correμtion among 11 parameters was calcuμted and contamination index was also determined, 33.3% of groundwater samples mostly collected around evaporation ponds had a contamination index above 3 and are considered extremely polluted.
文摘Using the RMA4 water quality model to simulate the water quality of Neijiang river in Zhenjiang, the result showed that： in the dry season the ranges of the concentration of various pollutants simulation of Neijiang were BOD5 3.2-5.2 mg/L, CODMn 4.7-6.8 mg/L, NH3-N 0.46-1.8 mg/L, TP 0.23-0.48 mg/L, and in the rainy period, the ranges of the concentration of various pollutants simulation of Neijiang were BOD5 0.69-0.73 mg/L, CODM, 1.9-2.3 mg/L, NH3-N 0.25-0.38 mg/L, TP 0.14-0.17 mg/L.These simulated values were closed to the monitoring values of pollution concentrations of Neijiang, which indicated that RMA4 was certain practical in the river water quality simulation, and simulation results have a certain degree of reliability, and it provides a scientific planning and management method for the river pollution control.
文摘The BOD5-DO (Biochemical Oxygen Demand in five days and Dissolved Oxygen) are important indexes that reflect the organic pollution extent of water,but the variation of the indexes is closely related with water temperature. The study on the coupled mathematical model reflecting the BOD5-DO with temperature is the key to reveal the mechanism of the migration and distribution of BOD5-DO in the water. The authors presented 1-D mathematical model for the three variables in vertical direction,and gave accurate solution for the equations under steady state,the relation among the variables and the method for solving BOD5-DO concentrations at different depth and temperature.
