This article examines the influence of seawater temperature and total dissolved solids (TDS) on reverse osmosis (RO) desalination in the Arabian Gulf region, with a focus on the impact of climate change. The study hig...This article examines the influence of seawater temperature and total dissolved solids (TDS) on reverse osmosis (RO) desalination in the Arabian Gulf region, with a focus on the impact of climate change. The study highlights the changes in seawater temperature and TDS levels over the years and discusses their effects on the efficiency and productivity of RO desalination plants. It emphasizes the importance of monitoring TDS levels and controlling seawater temperature to optimize water production. The article also suggests various solutions, including intensive pre-treatment, development of high-performance membranes, exploration of alternative water sources, and regulation of discharges into the Gulf, to ensure sustainable water supply in the face of rising TDS levels and seawater temperature. Further research and comprehensive monitoring are recommended to understand the implications of these findings and develop effective strategies for the management of marine resources in the Arabian Gulf.展开更多
This study presents a significant contribution to the field of water quality assessment and sustainable water management practices. By evaluating the levels of total dissolved solids (TDS) in seawater intakes within A...This study presents a significant contribution to the field of water quality assessment and sustainable water management practices. By evaluating the levels of total dissolved solids (TDS) in seawater intakes within Al-Khobar desalination production system, the study addresses a crucial aspect of water treatment and environmental impact assessment. The findings provide valuable insights into the variations and trends of TDS levels across different phases of the system, highlighting the importance of monitoring and management strategies. The study provided both gravimetric total dissolved solids (TDS) and electrical conductivity (EC) measurements to analyze TDS calculation factor and evaluate measurement accuracy. Results revealed significant variations in TDS levels across the sampling locations, with phase-2 exhibiting higher levels and greater fluctuations. Phase-3 displayed similar trends but with lower TDS levels, while phase-4 showed slightly different behavior with higher average TDS levels. EC measurements demonstrated a strong correlation with TDS, providing a reliable estimation. However, additional methods such as gravimetric analysis should be employed to confirm TDS measurements. The findings contribute to understanding water quality in the Al-Khobar desalination system, aiding in monitoring, management, and decision-making processes for water treatment and environmental impact assessment. The study enhances the credibility of water quality assessments and supports sustainable water management practices.展开更多
A relationship between electrical conductivity (EC) and total dissolved solids (TDS) was tested for solutions of same salinity levels with respect to different artificial salts with their combinations. Results showed ...A relationship between electrical conductivity (EC) and total dissolved solids (TDS) was tested for solutions of same salinity levels with respect to different artificial salts with their combinations. Results showed remarkable jumping at the order of the artificial salt sequence specially that of the magnesium type. A computer model is designed with an input of EC and TDS. The output will be the possible prevailing artificial salts. The accuracy of the model was tested by using the groundwater data of Safwan-Zubair area south of Iraq and it proved to be significant at 95% matching. The 5% unmatched results are due to the possibility of having more than one type of prevailing salt.展开更多
Water quality deterioration took place during infiltration process. Quality of the source water, climate conditions and amounts of added water are the major role players of the differentiation measures. Treated wastew...Water quality deterioration took place during infiltration process. Quality of the source water, climate conditions and amounts of added water are the major role players of the differentiation measures. Treated wastewater, rainwater and fresh groundwater were described within this study. It was found that the rainwater has an aggressive behavior with a high ability to dissolve soil salts. The amounts of Total Dissolved Solids (TDS) increase with infiltration process. Electrical conductivity (EC) increased by 600%. Plotting the fresh groundwater to the same conditions and experiment reflects the ability of this water to dissolve soil salts and increases the TDS by increasing the EC by a percentage of around 200%;while applying lower quality of water, the percentage of the EC of the treated wastewater increases to about 230% for the depth of 20 cm, which indicates the accumulation of the salts within this part of the soil, which leads to the deterioration of the soil quality, and decreases to about 160% for a depth of 60 cm. This differentiation could be a result of low permeability soils which tend to accumulate salts as a result of evaporation and then increase the salinity in the topsoil. Dissolution and plant uptake in the infiltrated take of minerals save the soil’s water from evaporation and do not allow salts to concentrate in soils. Moreover, plant uptake of soil water chemicals causes a decrease in some salt concentrations such as NO3, PO4, K, Na, and Cl and may conserve others.展开更多
High total dissolved solids (TDS) content is one of the most important pollution contributors in lakes in arid and semiarid areas.Ulansuhai Lake,located in Urad Qianqi,Inner Mongolia,China,was selected as the object o...High total dissolved solids (TDS) content is one of the most important pollution contributors in lakes in arid and semiarid areas.Ulansuhai Lake,located in Urad Qianqi,Inner Mongolia,China,was selected as the object of study.Temperatures and TDS contents of both ice and under-ice water were collected together with corresponding ice thickness.TDS profiles were drawn to show the distribution of TDS and to describe TDS migration.The results showed that about 80% (that is 3.602×10 8 kg) of TDS migrated from ice to water during the whole growth period of ice.Within ice layer,TDS migration only occurred during initial ice-on period,and then perished.The TDS in ice decreased with increasing ice thickness,following a negative exponential-like trend.Within under-ice water,the TDS migrated from ice-water interface to the entire water column under the effect of concentration gradient until the water TDS content was uniform.In winter,6.044×10 7 kg (16.78% of total TDS) TDS migrated from water to sediment,which indicated that winter is the best time for dredging sediment.The migration effect gives rise to TDS concentration in under-ice water and sediment that is likely to affect ecosystem and water quality of the Yellow River.The trend of transfer flux of ice-water and water-sediment interfaces is similar to that of ice growth rate,which reveals that ice growth rate is one of the determinants of TDS migration.The process and mechanism of TDS migration can be referenced by research on other lakes with similar TDS content in cold and arid areas.展开更多
Huge quantity of effluents is generated from pharmaceutical industries attributed to their wide array of manufacturing and maintenance processes. Wastewaters from pharmaceuticals are characterized by the presence of s...Huge quantity of effluents is generated from pharmaceutical industries attributed to their wide array of manufacturing and maintenance processes. Wastewaters from pharmaceuticals are characterized by the presence of solids, pH, temperature, biodegradable organic compounds, unusual turbidity, hardness and conductivity. Wastewater from pharmaceutical industry arising from various units is categorised as low total dissolved solids (LTDS) and high total dissolved solids (HTDS) based on the concentration of total dissolved solids. The present study focuses on treatment of LTDS using a combination of biological treatment followed by membrane process, reverse osmosis. This research presents the results from the pilot-scale studies focussed on biological treatment using SBR as pre-treatment for RO towards the removal of LTDS effluent. Three-month data on a daily basis is presented. The efficiency of the process was tested with a reduction in parameters like total dissolved solids and chemical oxygen demand. SBR tested for its suitability as a preliminary treatment for the Reverse Osmosis process during the months of August-October. The highest and lowest TDS reduction was recorded as 9.72% and ?4.67% in the month of August. The highest and least COD reduction was recorded as 87.28% and 80.66% in the same month. The highest and lowest TDS reduction was recorded as 0.84% and ?7.92% in the month of September. The highest and least COD reduction was recorded as 87.07% and 83.28% in the same month. The performance of RO tested for its efficiency in removing the TDS and COD after SBR as pre-treatment. The highest and lowest TDS reduction was recorded as 94.93% and 93.27% in the month of August. The highest and least COD reduction was recorded as 96.84% and 90.19% in the same month. The highest and lowest TDS reduction was recorded at 96.53% and 91.25% in the month of October. The highest and least COD reduction was recorded as 94.31% and 72.57% in the same month. SBR has proved to be a promising solution for pre-treatment removing all substances that might result in membrane fouling. Hence, the present study concludes that a combination of SBR and RO will be a promising solution for effective removal of TDS and COD from pharmaceutical wastewaters.展开更多
Total dissolved nitrogen(TDN) is an important parameter for assessing the nutrient cycling and status of natural waters.The accurate determination of TDN in natural waters is essential for assessing its contents and d...Total dissolved nitrogen(TDN) is an important parameter for assessing the nutrient cycling and status of natural waters.The accurate determination of TDN in natural waters is essential for assessing its contents and distinguishing different forms of nitrogen in the water.The TDN in various systems has been largely documented,and the concentrations of TDN are usually obtained using high-temperature catalytic(HTC) or persulfate oxidation(PO).However,the accuracy of these methods and their suitability for all types of natural waters are still unclear.To explore both methods in-depth,assorted samples were tested,including eight solutions composed of nitrogen-containing compounds(3 dissolved inorganic nitrogen fractions:NO_(3)^(-),NO_(2)^(-)and NH_(4)^(+);5 organic compounds:EDTA-2Na,vitamin B1,vitamin B12,amino acids,and urea) and 105 natural waters which were collected from an open ocean(Northwest Pacific Ocean,28),a marginal sea(Yellow Sea,34),an estuary(Huanghe River mouth,31),rivers(Huanghe River,4;Licun River,4),and precipitations(4 samples).The results showed that heterocycles and molecular dimensions had certain effects on the oxidation efficiency of the PO method but had little effect on HTC.There was no significant difference between the two methods for natural waters,but HTC was more suitable for deep-sea samples with low TDN concentrations(less than 10 μmol/L) and low organic activity.Overall,HTC has a relatively simple measurement process,a high degree of automation,and low error.Therefore,HTC can be recommended to determine the TDN of samples in freshwater and seawater.展开更多
In recirculating aquaculture systems(RASs),the effective treatment of aquaculture tailwater is essential to maintain the health of the RAS.This study investigated the optimal time and method for tailwater treatment du...In recirculating aquaculture systems(RASs),the effective treatment of aquaculture tailwater is essential to maintain the health of the RAS.This study investigated the optimal time and method for tailwater treatment during three periods of the aquaculture of the Litopenaeus vannamei:nursery(0–26 d),middle(27–57 d),and later(57–104 d).The variation of several water parameters during the dissolution of total suspended solid(TSS)in tailwater,applied with the effects of ozone on the microorganism and water quality parameters were investigated.Results showed that the TSS concentrations in tailwater decreased with time,although not significantly(P>0.05),whereas total ammonia nitrogen(TAN),nitrite(NO-2-N),and nitrate(NO_(3)^(-)-N)increased significantly(P<0.05).Therefore,TSS should be removed from the tailwater as early as possible,being most optimal within 4 h.Ozone removed 38.24%–48.95%of TSS,17.78%–90.14%of TAN,and 87.50%–98.90%of NO-2-N after 4 h of treatment.However,it resulted in the significant accumulation of NO_(3)^(-)-N.Moreover,the total number of Vibrio and bacterial counts in aquaculture tailwater was reduced completely by ozone within 4 h.Thus,these results provided technical details and data support for the effective treatment of tailwater from shrimp RAS.展开更多
Dam discharges over spillways are the main reason for the gas-supersaturated water generated in rivers.Local aquatic organisms,especially fish,readily develop gas bubble disease(GBD) in a river with total dissolved ga...Dam discharges over spillways are the main reason for the gas-supersaturated water generated in rivers.Local aquatic organisms,especially fish,readily develop gas bubble disease(GBD) in a river with total dissolved gas supersaturation(TDGS).Sometimes,fish will die after a specific exposure period,which negatively affects the biological equilibrium.In this study,the influence of TDGS on silver carp was explored.Silver carp were exposed to gas-supersaturated water with TDGS levels of 140%,135%,130%,125%,120%,and 110%to test the impact of TDGS.Some silver carp died when the TDGS level was 120%or higher,and all the silver carp exposed to a TDGS level of 140%died within10 h.In comparison with the Chinese sucker,Prenant's schizothoracin,and rock carp,silver carp seem less sensitive to TDGS.In addition,we tested the catalase(CAT) activity in the muscles and gills of silver carp after they were exposed to gas-supersaturated water with a TDGS level of140%.The CAT activity changed with time;it increased first and then decreased until it was lower than the initial CAT activity.The results of this study can provide basic data for developing a standard for environmental evaluation.展开更多
The elevated supersaturation of total dissolved gas(TDG)downstream of a high-dam spill has deleterious effects on fish in a large range.A one-dimensional(1-D)longitudinal model is optimal for the prediction of supersa...The elevated supersaturation of total dissolved gas(TDG)downstream of a high-dam spill has deleterious effects on fish in a large range.A one-dimensional(1-D)longitudinal model is optimal for the prediction of supersaturated TDG dissipation over a long distance.The key issue of the model is to determine the dissipation coefficient accurately.In agreement with field observations and experiment data,dimensional analysis and regression were performed to propose a formula for estimating the dissipation coefficient of supersaturated TDG in various rivers and reservoirs,and it involves the effects of the turbulence intensity,the hydro-pressure and the solid-liquid interface.The friction velocity,water depth,hydraulic radius and Froude number are independent variables in the formula which are easy to determine in practical applications.The 1-D longitudinal model is implemented to calculate the dissipation of TDG in a reach of the Jinsha River.Good agreement is found between the calculated results and field data for both the dissipation coefficient and the dissipation process.展开更多
More and more high dams have been constructed and operated in China. The total dissolved gas (TDG) supersaturation caused by dam discharge leads to gas bubble disease or even death of fish. Through a series of experim...More and more high dams have been constructed and operated in China. The total dissolved gas (TDG) supersaturation caused by dam discharge leads to gas bubble disease or even death of fish. Through a series of experiments, the conditions and requirements of supersaturated TDG generation were examined in this study. The results show that pressure (water depth), aeration, and bubble dissolution time are required for supersaturated TDG generation, and the air-water contact area and turbulence intensity are the main factors that affect the generation rate of supersaturated TDG. The TDG supersaturation levels can be reduced by discharging water to shallow shoals downstream of the dam or using negative pressure pipelines. Furthermore, the TDG supersaturation levels in stilling basins have no direct relationship with those in reservoirs. These results are of great importance for further research on the prediction of supersaturated TDG generation caused by dam discharge and aquatic protection.展开更多
Several methods for analysis of dissolved total phosphorus in seawater were reviewed. Discussions were focused on UV irradiation and persulphate oxidation methods which are the most popular dissolved organic phosphoru...Several methods for analysis of dissolved total phosphorus in seawater were reviewed. Discussions were focused on UV irradiation and persulphate oxidation methods which are the most popular dissolved organic phosphorus determination methods presently. The compounds used for the phosphorus recovery test were categorized into three groups according to their chemical structure. It was found that low power UV irradiation can decompose P-O-C or P-C bonds efficiently but may be inefficient for P-O-P bonds. Heating-bath in acid condition is useful for decomposing P-O-P bonds. Using the continuous flow analysis system (Auto-analyzer Ⅱ), UV digestion and heating-bath, series experiments were carried out based on the above analysis. Eleven model compounds were employed for the phosphorus recovery test and the factors influencing the decomposition efficiency of dissolved compounds containing phosphorus were clarified. Finally,the optimal design for determination of dissolved total phosphorus in seawater based on the routine continuous flow analysis system was presented. For the organic mono-phosphate, the recovery is more than 90% and a recovery of 33%～51% was obtained for inorganic or organic polyphosphates. Up to now, this is the highest decomposition efficiency for dissolved phosphorus based on the continuous flow analysis system.展开更多
The third Chinese National Arctic Research Expedition (3rd CHINARE-Arctic in 2008) was carried out from July to September 2008. During the survey, numerous sea water samples were taken for CO2 parameter measurement (i...The third Chinese National Arctic Research Expedition (3rd CHINARE-Arctic in 2008) was carried out from July to September 2008. During the survey, numerous sea water samples were taken for CO2 parameter measurement (including total alkalinity TA and total dissolved inorganic carbon DIC).The distribution of CO2 parameters in the Western Arctic Ocean was determined, and the controlling factors are addressed. The ranges of summertime TA, normalized TA (nTA), DIC and normalized DIC (nDIC) in the surface seawater were 1 757-2 229 μmol·kg 1, 2 383-2 722 μmol·kg 1, 1 681-2 034 μmol·kg 1, 2 119-2 600 μmol·kg 1, respectively. Becauseof dilution from ice meltwater, the surface TA and DIC concentrations were relatively low. TA in the upper 100m to the south of 78 N had good correlation with salinity, showing a conservative behavior. The distribution followed the seawater-river mixing line at salinity >30, then followed the seawater mixing line (diluted by river water to salinity = 30) with the ice meltwater. The DIC distribution in the Chukchi Sea was dominated by biological production or respiration of organic matter, whereas conservative mixing dominated the mixed layer TA distribution in the ice-free Canada Basin.展开更多
Background:In recent years,there has been an increasing interest in using high quantities of milk or milk replacer(MR)in heat-stressed calves to alleviate the negative effects of high environmental temperatures on the...Background:In recent years,there has been an increasing interest in using high quantities of milk or milk replacer(MR)in heat-stressed calves to alleviate the negative effects of high environmental temperatures on their performance.However,observations have indicated a decline in growth performance in the weaning and postweaning period,which might be optimized with increasing total solids(TS)in milk and weaning age.This study aims to optimize the effects of higher quantities of milk on late weaned calves'performance by increasing TS concentration or delivery route in summer conditions.Method:Forty-eight newborn Holstein calves were used in a 2×2 factorial arrangement with the factors of preweaning total plane of milk(PM)intake(low vs.high)and milk TS content(12%vs.17%).The treatments were(1)low PM(LPM)intake with 12%TS(TS intake=45.9 kg),(2)LPM intake with 17%TS(TS intake=65.1 kg),(3)high PM(HPM)intake with 12%TS(TS intake=63.7 kg);and(4)HPM intake with 17%TS(TS intake=90.3 kg).Calves were weaned at d 83,and the study was terminated at d 103 of age.Performance data(every 10 day),skeletal growth(d 80 and 100),ruminal fermentation parameters(d 48 and 91),and behavioral measurements(d 69,70,93 and 94)were analyzed as repeated measurements with PROC MIXED of SAS 9.4(SAS Institute Inc.,Cary,NC).Results:Calves receiving HPM consumed less PMR from d 44 to 83 of age,but they had higher ADG from d 24 to 53 of age compared to those fed LPM(PM×age,P<0.001).In addition,calves receiving milk with 17%TS had lower PMR intake from d 14 to 83 of age,but greater ADG from d 34 to 53 compared to those receiving milk with 12%TS(TS×age,P<0.001).Calves that received HPM had greater skeletal growth parameters compared to LPMfed calves,with a similar effect evident for calves fed milk with 17%TS compared with those fed milk with 12%TS.Calves receiving milk with 17%TS had greater fecal scores and diarrhea occurrence than those fed milk with 12%TS in HPM,but not LPM.Conclusions:Increasing PM and milk TS concentration improved growth in summer-exposed calves as demonstrated by increased pre-weaning ADG,pre-and post-weaning BW,and structural growth.展开更多
Produced water (PW) is the largest waste stream in the oil and gas industry. Water remains trapped for millions of years in the reservoir with oil and gas. When a hydrocarbon reservoir is infiltrated by a production w...Produced water (PW) is the largest waste stream in the oil and gas industry. Water remains trapped for millions of years in the reservoir with oil and gas. When a hydrocarbon reservoir is infiltrated by a production well, the produced fluids commonly contain water. The understanding of this water’s constituents and volumes is vital for the sustainable continuity of production operations, as PW has a number of negative impacts on the infrastructure integrity of the operation. On the other hand, PW can be an alternative source of irrigation water as well as of industrial salt. Interestingly, both the quantity as well as the quality of PW do not remain constant but can vary, both progressively and erratically, even over short periods of time. This paper discusses such a situation of variable PW in an oil and gas operation in the State of Kuwait.展开更多
文摘This article examines the influence of seawater temperature and total dissolved solids (TDS) on reverse osmosis (RO) desalination in the Arabian Gulf region, with a focus on the impact of climate change. The study highlights the changes in seawater temperature and TDS levels over the years and discusses their effects on the efficiency and productivity of RO desalination plants. It emphasizes the importance of monitoring TDS levels and controlling seawater temperature to optimize water production. The article also suggests various solutions, including intensive pre-treatment, development of high-performance membranes, exploration of alternative water sources, and regulation of discharges into the Gulf, to ensure sustainable water supply in the face of rising TDS levels and seawater temperature. Further research and comprehensive monitoring are recommended to understand the implications of these findings and develop effective strategies for the management of marine resources in the Arabian Gulf.
文摘This study presents a significant contribution to the field of water quality assessment and sustainable water management practices. By evaluating the levels of total dissolved solids (TDS) in seawater intakes within Al-Khobar desalination production system, the study addresses a crucial aspect of water treatment and environmental impact assessment. The findings provide valuable insights into the variations and trends of TDS levels across different phases of the system, highlighting the importance of monitoring and management strategies. The study provided both gravimetric total dissolved solids (TDS) and electrical conductivity (EC) measurements to analyze TDS calculation factor and evaluate measurement accuracy. Results revealed significant variations in TDS levels across the sampling locations, with phase-2 exhibiting higher levels and greater fluctuations. Phase-3 displayed similar trends but with lower TDS levels, while phase-4 showed slightly different behavior with higher average TDS levels. EC measurements demonstrated a strong correlation with TDS, providing a reliable estimation. However, additional methods such as gravimetric analysis should be employed to confirm TDS measurements. The findings contribute to understanding water quality in the Al-Khobar desalination system, aiding in monitoring, management, and decision-making processes for water treatment and environmental impact assessment. The study enhances the credibility of water quality assessments and supports sustainable water management practices.
文摘A relationship between electrical conductivity (EC) and total dissolved solids (TDS) was tested for solutions of same salinity levels with respect to different artificial salts with their combinations. Results showed remarkable jumping at the order of the artificial salt sequence specially that of the magnesium type. A computer model is designed with an input of EC and TDS. The output will be the possible prevailing artificial salts. The accuracy of the model was tested by using the groundwater data of Safwan-Zubair area south of Iraq and it proved to be significant at 95% matching. The 5% unmatched results are due to the possibility of having more than one type of prevailing salt.
文摘Water quality deterioration took place during infiltration process. Quality of the source water, climate conditions and amounts of added water are the major role players of the differentiation measures. Treated wastewater, rainwater and fresh groundwater were described within this study. It was found that the rainwater has an aggressive behavior with a high ability to dissolve soil salts. The amounts of Total Dissolved Solids (TDS) increase with infiltration process. Electrical conductivity (EC) increased by 600%. Plotting the fresh groundwater to the same conditions and experiment reflects the ability of this water to dissolve soil salts and increases the TDS by increasing the EC by a percentage of around 200%;while applying lower quality of water, the percentage of the EC of the treated wastewater increases to about 230% for the depth of 20 cm, which indicates the accumulation of the salts within this part of the soil, which leads to the deterioration of the soil quality, and decreases to about 160% for a depth of 60 cm. This differentiation could be a result of low permeability soils which tend to accumulate salts as a result of evaporation and then increase the salinity in the topsoil. Dissolution and plant uptake in the infiltrated take of minerals save the soil’s water from evaporation and do not allow salts to concentrate in soils. Moreover, plant uptake of soil water chemicals causes a decrease in some salt concentrations such as NO3, PO4, K, Na, and Cl and may conserve others.
基金Financial support was provided by the National Natural Science Foundation of China (50569002,50669004 and 51069007)Natural Science Foundation of Inner Mongolia (200711020604)Key Project from Department of Water Resources of Inner Mongolia (20080105)
文摘High total dissolved solids (TDS) content is one of the most important pollution contributors in lakes in arid and semiarid areas.Ulansuhai Lake,located in Urad Qianqi,Inner Mongolia,China,was selected as the object of study.Temperatures and TDS contents of both ice and under-ice water were collected together with corresponding ice thickness.TDS profiles were drawn to show the distribution of TDS and to describe TDS migration.The results showed that about 80% (that is 3.602×10 8 kg) of TDS migrated from ice to water during the whole growth period of ice.Within ice layer,TDS migration only occurred during initial ice-on period,and then perished.The TDS in ice decreased with increasing ice thickness,following a negative exponential-like trend.Within under-ice water,the TDS migrated from ice-water interface to the entire water column under the effect of concentration gradient until the water TDS content was uniform.In winter,6.044×10 7 kg (16.78% of total TDS) TDS migrated from water to sediment,which indicated that winter is the best time for dredging sediment.The migration effect gives rise to TDS concentration in under-ice water and sediment that is likely to affect ecosystem and water quality of the Yellow River.The trend of transfer flux of ice-water and water-sediment interfaces is similar to that of ice growth rate,which reveals that ice growth rate is one of the determinants of TDS migration.The process and mechanism of TDS migration can be referenced by research on other lakes with similar TDS content in cold and arid areas.
文摘Huge quantity of effluents is generated from pharmaceutical industries attributed to their wide array of manufacturing and maintenance processes. Wastewaters from pharmaceuticals are characterized by the presence of solids, pH, temperature, biodegradable organic compounds, unusual turbidity, hardness and conductivity. Wastewater from pharmaceutical industry arising from various units is categorised as low total dissolved solids (LTDS) and high total dissolved solids (HTDS) based on the concentration of total dissolved solids. The present study focuses on treatment of LTDS using a combination of biological treatment followed by membrane process, reverse osmosis. This research presents the results from the pilot-scale studies focussed on biological treatment using SBR as pre-treatment for RO towards the removal of LTDS effluent. Three-month data on a daily basis is presented. The efficiency of the process was tested with a reduction in parameters like total dissolved solids and chemical oxygen demand. SBR tested for its suitability as a preliminary treatment for the Reverse Osmosis process during the months of August-October. The highest and lowest TDS reduction was recorded as 9.72% and ?4.67% in the month of August. The highest and least COD reduction was recorded as 87.28% and 80.66% in the same month. The highest and lowest TDS reduction was recorded as 0.84% and ?7.92% in the month of September. The highest and least COD reduction was recorded as 87.07% and 83.28% in the same month. The performance of RO tested for its efficiency in removing the TDS and COD after SBR as pre-treatment. The highest and lowest TDS reduction was recorded as 94.93% and 93.27% in the month of August. The highest and least COD reduction was recorded as 96.84% and 90.19% in the same month. The highest and lowest TDS reduction was recorded at 96.53% and 91.25% in the month of October. The highest and least COD reduction was recorded as 94.31% and 72.57% in the same month. SBR has proved to be a promising solution for pre-treatment removing all substances that might result in membrane fouling. Hence, the present study concludes that a combination of SBR and RO will be a promising solution for effective removal of TDS and COD from pharmaceutical wastewaters.
基金The National Key Research and Development Project of China under contract No.2019YFC1407802the Fund of State Environmental Protection Key Laboratory of Coastal Ecosystem under contract No.202112+3 种基金the Open Fund of Key Laboratory of Marine Ecological Environment Science and EngineeringMinistry of Natural Resources under contract No.MESE-2019-06the National Natural Science Foundation of China under contract No.41876078the Shandong Provincial Natural Science Foundation of China under contract No.ZR2018MD016。
文摘Total dissolved nitrogen(TDN) is an important parameter for assessing the nutrient cycling and status of natural waters.The accurate determination of TDN in natural waters is essential for assessing its contents and distinguishing different forms of nitrogen in the water.The TDN in various systems has been largely documented,and the concentrations of TDN are usually obtained using high-temperature catalytic(HTC) or persulfate oxidation(PO).However,the accuracy of these methods and their suitability for all types of natural waters are still unclear.To explore both methods in-depth,assorted samples were tested,including eight solutions composed of nitrogen-containing compounds(3 dissolved inorganic nitrogen fractions:NO_(3)^(-),NO_(2)^(-)and NH_(4)^(+);5 organic compounds:EDTA-2Na,vitamin B1,vitamin B12,amino acids,and urea) and 105 natural waters which were collected from an open ocean(Northwest Pacific Ocean,28),a marginal sea(Yellow Sea,34),an estuary(Huanghe River mouth,31),rivers(Huanghe River,4;Licun River,4),and precipitations(4 samples).The results showed that heterocycles and molecular dimensions had certain effects on the oxidation efficiency of the PO method but had little effect on HTC.There was no significant difference between the two methods for natural waters,but HTC was more suitable for deep-sea samples with low TDN concentrations(less than 10 μmol/L) and low organic activity.Overall,HTC has a relatively simple measurement process,a high degree of automation,and low error.Therefore,HTC can be recommended to determine the TDN of samples in freshwater and seawater.
基金Supported by the National Key R&D Program of China(No.2019YFD0900502)。
文摘In recirculating aquaculture systems(RASs),the effective treatment of aquaculture tailwater is essential to maintain the health of the RAS.This study investigated the optimal time and method for tailwater treatment during three periods of the aquaculture of the Litopenaeus vannamei:nursery(0–26 d),middle(27–57 d),and later(57–104 d).The variation of several water parameters during the dissolution of total suspended solid(TSS)in tailwater,applied with the effects of ozone on the microorganism and water quality parameters were investigated.Results showed that the TSS concentrations in tailwater decreased with time,although not significantly(P>0.05),whereas total ammonia nitrogen(TAN),nitrite(NO-2-N),and nitrate(NO_(3)^(-)-N)increased significantly(P<0.05).Therefore,TSS should be removed from the tailwater as early as possible,being most optimal within 4 h.Ozone removed 38.24%–48.95%of TSS,17.78%–90.14%of TAN,and 87.50%–98.90%of NO-2-N after 4 h of treatment.However,it resulted in the significant accumulation of NO_(3)^(-)-N.Moreover,the total number of Vibrio and bacterial counts in aquaculture tailwater was reduced completely by ozone within 4 h.Thus,these results provided technical details and data support for the effective treatment of tailwater from shrimp RAS.
基金supported by the National Natural Science Foundation of China(Grant No.51379136)
文摘Dam discharges over spillways are the main reason for the gas-supersaturated water generated in rivers.Local aquatic organisms,especially fish,readily develop gas bubble disease(GBD) in a river with total dissolved gas supersaturation(TDGS).Sometimes,fish will die after a specific exposure period,which negatively affects the biological equilibrium.In this study,the influence of TDGS on silver carp was explored.Silver carp were exposed to gas-supersaturated water with TDGS levels of 140%,135%,130%,125%,120%,and 110%to test the impact of TDGS.Some silver carp died when the TDGS level was 120%or higher,and all the silver carp exposed to a TDGS level of 140%died within10 h.In comparison with the Chinese sucker,Prenant's schizothoracin,and rock carp,silver carp seem less sensitive to TDGS.In addition,we tested the catalase(CAT) activity in the muscles and gills of silver carp after they were exposed to gas-supersaturated water with a TDGS level of140%.The CAT activity changed with time;it increased first and then decreased until it was lower than the initial CAT activity.The results of this study can provide basic data for developing a standard for environmental evaluation.
基金Projects(51179111,51279115)supported by the National Natural Science Foundation of ChinaProject(20110181110073)supported by the Doctoral Programs Foundation of Ministry of Education of China
文摘The elevated supersaturation of total dissolved gas(TDG)downstream of a high-dam spill has deleterious effects on fish in a large range.A one-dimensional(1-D)longitudinal model is optimal for the prediction of supersaturated TDG dissipation over a long distance.The key issue of the model is to determine the dissipation coefficient accurately.In agreement with field observations and experiment data,dimensional analysis and regression were performed to propose a formula for estimating the dissipation coefficient of supersaturated TDG in various rivers and reservoirs,and it involves the effects of the turbulence intensity,the hydro-pressure and the solid-liquid interface.The friction velocity,water depth,hydraulic radius and Froude number are independent variables in the formula which are easy to determine in practical applications.The 1-D longitudinal model is implemented to calculate the dissipation of TDG in a reach of the Jinsha River.Good agreement is found between the calculated results and field data for both the dissipation coefficient and the dissipation process.
基金supported by the National Natural Science Foundation of China (Grant No. 50979063)
文摘More and more high dams have been constructed and operated in China. The total dissolved gas (TDG) supersaturation caused by dam discharge leads to gas bubble disease or even death of fish. Through a series of experiments, the conditions and requirements of supersaturated TDG generation were examined in this study. The results show that pressure (water depth), aeration, and bubble dissolution time are required for supersaturated TDG generation, and the air-water contact area and turbulence intensity are the main factors that affect the generation rate of supersaturated TDG. The TDG supersaturation levels can be reduced by discharging water to shallow shoals downstream of the dam or using negative pressure pipelines. Furthermore, the TDG supersaturation levels in stilling basins have no direct relationship with those in reservoirs. These results are of great importance for further research on the prediction of supersaturated TDG generation caused by dam discharge and aquatic protection.
基金The research was supported by the National Basic Research Program(“973”Program)of China under contract No.2002CB412405the Key Science and Technology Plan of the Ministry of Education of China under contract No.[2000]156-00079the Joint Sino-German Project under contract No.03F0189A.
文摘Several methods for analysis of dissolved total phosphorus in seawater were reviewed. Discussions were focused on UV irradiation and persulphate oxidation methods which are the most popular dissolved organic phosphorus determination methods presently. The compounds used for the phosphorus recovery test were categorized into three groups according to their chemical structure. It was found that low power UV irradiation can decompose P-O-C or P-C bonds efficiently but may be inefficient for P-O-P bonds. Heating-bath in acid condition is useful for decomposing P-O-P bonds. Using the continuous flow analysis system (Auto-analyzer Ⅱ), UV digestion and heating-bath, series experiments were carried out based on the above analysis. Eleven model compounds were employed for the phosphorus recovery test and the factors influencing the decomposition efficiency of dissolved compounds containing phosphorus were clarified. Finally,the optimal design for determination of dissolved total phosphorus in seawater based on the routine continuous flow analysis system was presented. For the organic mono-phosphate, the recovery is more than 90% and a recovery of 33%～51% was obtained for inorganic or organic polyphosphates. Up to now, this is the highest decomposition efficiency for dissolved phosphorus based on the continuous flow analysis system.
基金funded from the National Natural Science Foundation of China (Grant no. 40976116)the Scientific Research Foundation of Third Institute of Oceanography,SOA (Grant nos. 2010011, 2010001)+1 种基金sponsored by the China Program for International Polar Year 2007–2008the Special Research Foundation for Public Welfare Marine Program(Grant no. 201105022–2)
文摘The third Chinese National Arctic Research Expedition (3rd CHINARE-Arctic in 2008) was carried out from July to September 2008. During the survey, numerous sea water samples were taken for CO2 parameter measurement (including total alkalinity TA and total dissolved inorganic carbon DIC).The distribution of CO2 parameters in the Western Arctic Ocean was determined, and the controlling factors are addressed. The ranges of summertime TA, normalized TA (nTA), DIC and normalized DIC (nDIC) in the surface seawater were 1 757-2 229 μmol·kg 1, 2 383-2 722 μmol·kg 1, 1 681-2 034 μmol·kg 1, 2 119-2 600 μmol·kg 1, respectively. Becauseof dilution from ice meltwater, the surface TA and DIC concentrations were relatively low. TA in the upper 100m to the south of 78 N had good correlation with salinity, showing a conservative behavior. The distribution followed the seawater-river mixing line at salinity >30, then followed the seawater mixing line (diluted by river water to salinity = 30) with the ice meltwater. The DIC distribution in the Chukchi Sea was dominated by biological production or respiration of organic matter, whereas conservative mixing dominated the mixed layer TA distribution in the ice-free Canada Basin.
基金The authors acknowledge Isfahan University of Technology,Isfahan,Iran(IUT)for their support with financial resources and research facilitiesFurther acknowledgment goes to Mahdi Mohsenian and Soha Agreen Tech Company(Tehran,Iran)for donating milk powder and funding this project.
文摘Background:In recent years,there has been an increasing interest in using high quantities of milk or milk replacer(MR)in heat-stressed calves to alleviate the negative effects of high environmental temperatures on their performance.However,observations have indicated a decline in growth performance in the weaning and postweaning period,which might be optimized with increasing total solids(TS)in milk and weaning age.This study aims to optimize the effects of higher quantities of milk on late weaned calves'performance by increasing TS concentration or delivery route in summer conditions.Method:Forty-eight newborn Holstein calves were used in a 2×2 factorial arrangement with the factors of preweaning total plane of milk(PM)intake(low vs.high)and milk TS content(12%vs.17%).The treatments were(1)low PM(LPM)intake with 12%TS(TS intake=45.9 kg),(2)LPM intake with 17%TS(TS intake=65.1 kg),(3)high PM(HPM)intake with 12%TS(TS intake=63.7 kg);and(4)HPM intake with 17%TS(TS intake=90.3 kg).Calves were weaned at d 83,and the study was terminated at d 103 of age.Performance data(every 10 day),skeletal growth(d 80 and 100),ruminal fermentation parameters(d 48 and 91),and behavioral measurements(d 69,70,93 and 94)were analyzed as repeated measurements with PROC MIXED of SAS 9.4(SAS Institute Inc.,Cary,NC).Results:Calves receiving HPM consumed less PMR from d 44 to 83 of age,but they had higher ADG from d 24 to 53 of age compared to those fed LPM(PM×age,P<0.001).In addition,calves receiving milk with 17%TS had lower PMR intake from d 14 to 83 of age,but greater ADG from d 34 to 53 compared to those receiving milk with 12%TS(TS×age,P<0.001).Calves that received HPM had greater skeletal growth parameters compared to LPMfed calves,with a similar effect evident for calves fed milk with 17%TS compared with those fed milk with 12%TS.Calves receiving milk with 17%TS had greater fecal scores and diarrhea occurrence than those fed milk with 12%TS in HPM,but not LPM.Conclusions:Increasing PM and milk TS concentration improved growth in summer-exposed calves as demonstrated by increased pre-weaning ADG,pre-and post-weaning BW,and structural growth.
文摘Produced water (PW) is the largest waste stream in the oil and gas industry. Water remains trapped for millions of years in the reservoir with oil and gas. When a hydrocarbon reservoir is infiltrated by a production well, the produced fluids commonly contain water. The understanding of this water’s constituents and volumes is vital for the sustainable continuity of production operations, as PW has a number of negative impacts on the infrastructure integrity of the operation. On the other hand, PW can be an alternative source of irrigation water as well as of industrial salt. Interestingly, both the quantity as well as the quality of PW do not remain constant but can vary, both progressively and erratically, even over short periods of time. This paper discusses such a situation of variable PW in an oil and gas operation in the State of Kuwait.
