The turbidity criterion for the product water of a WTP according to the State Project ‘863’ on the safeguard technology of drinking water in the southern areas of China is 0.1 NTU. The turbidity removal in the activ...The turbidity criterion for the product water of a WTP according to the State Project ‘863’ on the safeguard technology of drinking water in the southern areas of China is 0.1 NTU. The turbidity removal in the activated carbon filter was analyzed in a pilot-scale test and an innovative technology to improve the turbidity removal in a biologically activated carbon (BAC) filter was put forward in order to meet the criterion. Experimental results showed that the enhanced filtration by adding polymerized aluminium chloride (PAC) into the BAC filter was quite effective in turbidity control. The effluent turbidity was kept at a stable level (mean) of 0.033 NTU with a high removal of about 80% for influent turbidity of 0.110-0.240 NTU with an addition of PAC at 0.05 mg L -1, meeting the requirement for filtrate turbidity equal to or less than 0.1NTUC totally. In addition, the larger the PAC dosage was, the lower the effluent turbidity was. However, further improvement of turbidity removal was not obvious for PAC dosages beyond 0.10 mg L -1, and an optimal PAC dosage in the range of 0.]05-0.10 mg L -1 was proposed.展开更多
Changes in the regulatory requirements and the forthcoming Disinfectant/Disinfection By-Products （D/DBP） Rule will require that drinking water treatment facilities be operated to achieve maximum removals of particle...Changes in the regulatory requirements and the forthcoming Disinfectant/Disinfection By-Products （D/DBP） Rule will require that drinking water treatment facilities be operated to achieve maximum removals of particles and disinfectant tolerant microorganisms as well as natural organic matter （NOM）. For drinking water production, the use of membrane filtration processes such as microfiltration and ultrafiltration （MF/UF） alone to satisfy the turbidity, particle and microorganism removal a requirement of the surface water treatment regulation （SWTR） is not enough. MF/UF treatment processes can achieve only nominal （10 percent） removal of disinfection by-products （DBP） precursors （James, et al., 1995）. On the other hand, too fast fouling can make the filtration processes more difficult to carry on. To solve these problems, many authors have been interested in installing coagulation pretreatment before membrane filtration to improve membrane performance. However, previous studies reported conflicting results. Some supported the effectiveness of coagulation pretreatment, while others contended that coagulation aggravated membrane performance. This research aims to identify the effects of coagulation pretreatment on membrane filtration through a pilot study using PVDF membrane in combination with analyzing the rationale of coagulation. Another objective of this research was to evaluate the different impacts on membrane performance of using different membrane modules （the submerged module and pressured module）. The results showed that coagulation pretreatment greatly improved the membrane performance, extending the filtration time as well as reducing the permeated organic level, and that the submerged module is much more efficient than the pressured module.展开更多
文摘The turbidity criterion for the product water of a WTP according to the State Project ‘863’ on the safeguard technology of drinking water in the southern areas of China is 0.1 NTU. The turbidity removal in the activated carbon filter was analyzed in a pilot-scale test and an innovative technology to improve the turbidity removal in a biologically activated carbon (BAC) filter was put forward in order to meet the criterion. Experimental results showed that the enhanced filtration by adding polymerized aluminium chloride (PAC) into the BAC filter was quite effective in turbidity control. The effluent turbidity was kept at a stable level (mean) of 0.033 NTU with a high removal of about 80% for influent turbidity of 0.110-0.240 NTU with an addition of PAC at 0.05 mg L -1, meeting the requirement for filtrate turbidity equal to or less than 0.1NTUC totally. In addition, the larger the PAC dosage was, the lower the effluent turbidity was. However, further improvement of turbidity removal was not obvious for PAC dosages beyond 0.10 mg L -1, and an optimal PAC dosage in the range of 0.]05-0.10 mg L -1 was proposed.
文摘Changes in the regulatory requirements and the forthcoming Disinfectant/Disinfection By-Products （D/DBP） Rule will require that drinking water treatment facilities be operated to achieve maximum removals of particles and disinfectant tolerant microorganisms as well as natural organic matter （NOM）. For drinking water production, the use of membrane filtration processes such as microfiltration and ultrafiltration （MF/UF） alone to satisfy the turbidity, particle and microorganism removal a requirement of the surface water treatment regulation （SWTR） is not enough. MF/UF treatment processes can achieve only nominal （10 percent） removal of disinfection by-products （DBP） precursors （James, et al., 1995）. On the other hand, too fast fouling can make the filtration processes more difficult to carry on. To solve these problems, many authors have been interested in installing coagulation pretreatment before membrane filtration to improve membrane performance. However, previous studies reported conflicting results. Some supported the effectiveness of coagulation pretreatment, while others contended that coagulation aggravated membrane performance. This research aims to identify the effects of coagulation pretreatment on membrane filtration through a pilot study using PVDF membrane in combination with analyzing the rationale of coagulation. Another objective of this research was to evaluate the different impacts on membrane performance of using different membrane modules （the submerged module and pressured module）. The results showed that coagulation pretreatment greatly improved the membrane performance, extending the filtration time as well as reducing the permeated organic level, and that the submerged module is much more efficient than the pressured module.
