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
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
Palm oil industry is the most important agro-industry in Malaysia, but its by-product-palm oil mill effluent （POME）, posed a great threat to water environment. In the past decades, several treatment and disposal met...Palm oil industry is the most important agro-industry in Malaysia, but its by-product-palm oil mill effluent （POME）, posed a great threat to water environment. In the past decades, several treatment and disposal methods have been proposed and investigated to solve this problem. A two-stage pilot-scale plant was designed and constructed for POME treatment. Anaerobic digestion and aerobic biodegradation constituted the first biological stage, while ultrafiltration （UF） and reverse osmosis （RO） membrane units were combined as the second membrane separation stage. In the anaerobic expanded granular sludge bed （EGSB） reactor, about 43% organic matter in POME was converted into biogas, and COD reduction efficiency reached 93% and 22% in EGSB and the following aerobic reactor, respectively. With the treatment in the first biological stage, suspended solids and oil also decreased to a low degree. All these alleviated the membrane fouling and prolonged the membrane life. In the membrane process unit, almost all the suspended solids were captured by UF membranes, while RO membrane excluded most of the dissolved solids or inorganic salts from RO permeate. After the whole treatment processes, organic matter in POME expressed by BOD and COD was removed almost thoroughly. Suspended solids and color were not detectable in RO permeate any more, and mineral elements only existed in trace amount （except for K and Na）. The high-quality effluent was crystal clear and could be used as the boiler feed water.展开更多
Water and energy shortages came due to rapid population growth, living standards and rapid development in the agriculture and industrial sectors. Desalination tends to be one of the most promising water solutions;howe...Water and energy shortages came due to rapid population growth, living standards and rapid development in the agriculture and industrial sectors. Desalination tends to be one of the most promising water solutions;however, it is a process of intense energy. Membrane Capacitive Deionization (MCDI) has received considerable interest as a promising desalination technology, and MCDI research has increased significantly over the last 10 years. In addition, there are no guidelines for the design of Capacitive Deionization (CDI) implementation strategies for individual applications. This study, therefore;provides an alternative of CDI’s recent application developments, with emphasis placed on hybrid systems to address the technological needs of different relevant fields. The MCDI’s energy consumption is compared with the reverse osmosis literature data based on experimental data from laboratory-scale system. The study demonstrates that MCDI technology is a promising technology in the next few years with an extreme competition in water recovery, energy consumption and salt removal for reverse osmosis.展开更多
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Palm oil industry is the most important agro-industry in Malaysia, but its by-product-palm oil mill effluent （POME）, posed a great threat to water environment. In the past decades, several treatment and disposal methods have been proposed and investigated to solve this problem. A two-stage pilot-scale plant was designed and constructed for POME treatment. Anaerobic digestion and aerobic biodegradation constituted the first biological stage, while ultrafiltration （UF） and reverse osmosis （RO） membrane units were combined as the second membrane separation stage. In the anaerobic expanded granular sludge bed （EGSB） reactor, about 43% organic matter in POME was converted into biogas, and COD reduction efficiency reached 93% and 22% in EGSB and the following aerobic reactor, respectively. With the treatment in the first biological stage, suspended solids and oil also decreased to a low degree. All these alleviated the membrane fouling and prolonged the membrane life. In the membrane process unit, almost all the suspended solids were captured by UF membranes, while RO membrane excluded most of the dissolved solids or inorganic salts from RO permeate. After the whole treatment processes, organic matter in POME expressed by BOD and COD was removed almost thoroughly. Suspended solids and color were not detectable in RO permeate any more, and mineral elements only existed in trace amount （except for K and Na）. The high-quality effluent was crystal clear and could be used as the boiler feed water.
文摘Water and energy shortages came due to rapid population growth, living standards and rapid development in the agriculture and industrial sectors. Desalination tends to be one of the most promising water solutions;however, it is a process of intense energy. Membrane Capacitive Deionization (MCDI) has received considerable interest as a promising desalination technology, and MCDI research has increased significantly over the last 10 years. In addition, there are no guidelines for the design of Capacitive Deionization (CDI) implementation strategies for individual applications. This study, therefore;provides an alternative of CDI’s recent application developments, with emphasis placed on hybrid systems to address the technological needs of different relevant fields. The MCDI’s energy consumption is compared with the reverse osmosis literature data based on experimental data from laboratory-scale system. The study demonstrates that MCDI technology is a promising technology in the next few years with an extreme competition in water recovery, energy consumption and salt removal for reverse osmosis.
