The biofouling of RO （Reverse Osmosis） system is one of the most common problems in highly contaminated demineralization and wastewater reuse system. The biological fouling occurs due to the bacteria growth and prol...The biofouling of RO （Reverse Osmosis） system is one of the most common problems in highly contaminated demineralization and wastewater reuse system. The biological fouling occurs due to the bacteria growth and proliferation under nutritive environment, resulting in a dramatic increase of dP （differential pressure） in the RO system, which requires frequent system shutdown for cleaning. This paper discusses the effectiveness of low-dP RO element and periodic flushing on the biofouling scheme of industrial steel mill wastewater reuse system. The low-dP RO element is able to provide low RO system dP, which is expressed to be lower biofouling starting point during the industrial system operation. However, the periodic flushing utilizes fresh water to remove the biofilm deposit along with feed channel. The long term operation performance demonstrated strong caustic is effective in removing the biofilm and recovering RO system performance. It is experimentally validated that, in the case of a high biofouling environment, low-dP RO element and periodic flushing is able to extend the cleaning cycles by 36.6% and 11.4%, respectively. Meanwhile, a joint application of both methods is proven to improve the biofouling control and extend the cleaning cycle by 62.5%, as compared to standard RO technology.展开更多
Tanneries reusing wastewater by combination of conventional and advanced Reverse Osmosis (RO) treatment technologies were assessed for technical and economic viabilities. Conventional treatment methods such as neutral...Tanneries reusing wastewater by combination of conventional and advanced Reverse Osmosis (RO) treatment technologies were assessed for technical and economic viabilities. Conventional treatment methods such as neutralization, clari-flocculation and biological processes are followed to clean the effluents before feeding to RO membrane modules. The characteristics of untreated composite effluents such as pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total dissolved solids (TDS), and total chromium were in the range of 4.00-4.60, 680-3600 mg/L, 1698-7546 mg/L, 980-1480 mg/L, 4200-14500 mg/L, and 26.4-190 mg/L, respectively. Inorganic ions like Ca2+, Na+, Cl– and SO42– were found more in the wastewaters. Conventional treatments significantly removed the organic pollutants however failed to remove dissolved inorganic salts. Membrane technology removed the salts as well as remaining organic pollutants and the product water is reused in the process. The studied tanneries (5 numbers) have achieved 93-98%, 92-99% and 91-96% removal of TDS, sodium and chloride, respectively. Seventy to eighty five percentage of wastewater was recovered and recycled in the industrial processes. The rejects are subject to either solar evaporation system or Multiple Effect Evaporation (MEE) technology. The resulting salts are collected in polythene bags and disposed into scientifically managed secured land fill (SLF) site. The cost of wastewater treatment for operation and maintenances of RO including the pre-treatments (conventional methods) is INR 100-110 m-3.展开更多
Brine salty water that is produced from Reverse Osmosis desalination plants usually has very large quantity and contains much higher salts ratio than that found in the sea. The disposal of such brine water has risks o...Brine salty water that is produced from Reverse Osmosis desalination plants usually has very large quantity and contains much higher salts ratio than that found in the sea. The disposal of such brine water has risks on environment. The objective of the research is to investigate the best brine disposal option in Gaza Strip. Five options for the disposal of brine were studied: 1) disposal of brine to the sea;2) discharge of brine to wastewater plant;3) deep well injection;4) evaporation pond and 5) land irrigation. The new desalination plant Short-Term Low Volume (STLV) of a capacity of 6000 m3/d was used as a case study. Initially, the cost for each option was calculated separately, where it was found that the least cost is to pump the brine to the sea without affecting the seawater and marine life. To support this decision, two methods were used to reach the optimal option for the disposal of brine: Multi-Criteria Analysis (MCA) and Analytic Hierarchy Process (AHP). In MCA the measurement includes: economic, environmental, technical, political and social aspects, depending on a group of academics and experts in that field to fill in the questionnaire, which is a part of the analysis. As a result of that, the highest percentage among other options goes to pump the brine directly to the sea. On the other hand, the second method, which is Analytic Hierarchy Process (AHP), used the method of matrices among the different options and linked it with the standards that have been selected in the first method (MCDA). AHP method indicated also the best disposal of brine by pumping the brine to the sea.展开更多
In this paper, carbon dioxide and polyacrylamide were used to improve the method to abstract magnesium from desalination brine. Experimental results showed that calcium ion in the desali-nation brine can be effectivel...In this paper, carbon dioxide and polyacrylamide were used to improve the method to abstract magnesium from desalination brine. Experimental results showed that calcium ion in the desali-nation brine can be effectively removed using carbon dioxide, which thereby improves the purity and reaction efficiency of the magnesium hydrate precipitate. 0.1% - 0.2% PAM could help to promote the precipitation of magnesium hydrate colloid. And when hydroxyl anion was between 110% - 130% of theoretical amount, yield of magnesium hydrate exceeds 70% at standing time of 60 hours.展开更多
文摘The biofouling of RO （Reverse Osmosis） system is one of the most common problems in highly contaminated demineralization and wastewater reuse system. The biological fouling occurs due to the bacteria growth and proliferation under nutritive environment, resulting in a dramatic increase of dP （differential pressure） in the RO system, which requires frequent system shutdown for cleaning. This paper discusses the effectiveness of low-dP RO element and periodic flushing on the biofouling scheme of industrial steel mill wastewater reuse system. The low-dP RO element is able to provide low RO system dP, which is expressed to be lower biofouling starting point during the industrial system operation. However, the periodic flushing utilizes fresh water to remove the biofilm deposit along with feed channel. The long term operation performance demonstrated strong caustic is effective in removing the biofilm and recovering RO system performance. It is experimentally validated that, in the case of a high biofouling environment, low-dP RO element and periodic flushing is able to extend the cleaning cycles by 36.6% and 11.4%, respectively. Meanwhile, a joint application of both methods is proven to improve the biofouling control and extend the cleaning cycle by 62.5%, as compared to standard RO technology.
文摘Tanneries reusing wastewater by combination of conventional and advanced Reverse Osmosis (RO) treatment technologies were assessed for technical and economic viabilities. Conventional treatment methods such as neutralization, clari-flocculation and biological processes are followed to clean the effluents before feeding to RO membrane modules. The characteristics of untreated composite effluents such as pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total dissolved solids (TDS), and total chromium were in the range of 4.00-4.60, 680-3600 mg/L, 1698-7546 mg/L, 980-1480 mg/L, 4200-14500 mg/L, and 26.4-190 mg/L, respectively. Inorganic ions like Ca2+, Na+, Cl– and SO42– were found more in the wastewaters. Conventional treatments significantly removed the organic pollutants however failed to remove dissolved inorganic salts. Membrane technology removed the salts as well as remaining organic pollutants and the product water is reused in the process. The studied tanneries (5 numbers) have achieved 93-98%, 92-99% and 91-96% removal of TDS, sodium and chloride, respectively. Seventy to eighty five percentage of wastewater was recovered and recycled in the industrial processes. The rejects are subject to either solar evaporation system or Multiple Effect Evaporation (MEE) technology. The resulting salts are collected in polythene bags and disposed into scientifically managed secured land fill (SLF) site. The cost of wastewater treatment for operation and maintenances of RO including the pre-treatments (conventional methods) is INR 100-110 m-3.
文摘Brine salty water that is produced from Reverse Osmosis desalination plants usually has very large quantity and contains much higher salts ratio than that found in the sea. The disposal of such brine water has risks on environment. The objective of the research is to investigate the best brine disposal option in Gaza Strip. Five options for the disposal of brine were studied: 1) disposal of brine to the sea;2) discharge of brine to wastewater plant;3) deep well injection;4) evaporation pond and 5) land irrigation. The new desalination plant Short-Term Low Volume (STLV) of a capacity of 6000 m3/d was used as a case study. Initially, the cost for each option was calculated separately, where it was found that the least cost is to pump the brine to the sea without affecting the seawater and marine life. To support this decision, two methods were used to reach the optimal option for the disposal of brine: Multi-Criteria Analysis (MCA) and Analytic Hierarchy Process (AHP). In MCA the measurement includes: economic, environmental, technical, political and social aspects, depending on a group of academics and experts in that field to fill in the questionnaire, which is a part of the analysis. As a result of that, the highest percentage among other options goes to pump the brine directly to the sea. On the other hand, the second method, which is Analytic Hierarchy Process (AHP), used the method of matrices among the different options and linked it with the standards that have been selected in the first method (MCDA). AHP method indicated also the best disposal of brine by pumping the brine to the sea.
文摘In this paper, carbon dioxide and polyacrylamide were used to improve the method to abstract magnesium from desalination brine. Experimental results showed that calcium ion in the desali-nation brine can be effectively removed using carbon dioxide, which thereby improves the purity and reaction efficiency of the magnesium hydrate precipitate. 0.1% - 0.2% PAM could help to promote the precipitation of magnesium hydrate colloid. And when hydroxyl anion was between 110% - 130% of theoretical amount, yield of magnesium hydrate exceeds 70% at standing time of 60 hours.
