Chlorine-resistant bacteria (CRB) in the reverse osmosis system for wastewater reclamation: isolation, identification and membrane fouling mechanisms

2021 ◽  
pp. 117966
Author(s):  
Li-Wei Luo ◽  
Yin-Hu Wu ◽  
Gen-Qiang Chen ◽  
Hao-Bin Wang ◽  
Yun-Hong Wang ◽  
...  
2013 ◽  
Vol 3 (3) ◽  
pp. 260-267
Author(s):  
Ho-Young Jeong ◽  
Yoon-Jin Kim ◽  
Ji-Hee Han ◽  
Dong-Ha Kim ◽  
Jinsik Sohn ◽  
...  

Wastewater reclamation is where wastewater from various sources is purified so the water can be used by human consumption. Among many treatment options, membranes have gained an important place in wastewater reclamation. It allows the production of high quality water from wastewater, with a small footprint and affordable energy consumption. Nevertheless, membrane fouling is regarded as a serious problem due to the high fouling potential of wastewater. In this study, we applied ultraviolet (UV) processes as a pretreatment for membrane systems that are used for wastewater reclamation. Low pressure UV (LUV) and pulsed UV (PUV) were used to decompose or alter the organics in the feed water of the membranes. Effluent organic matter was characterized by total organic carbon (TOC) and UV absorbance (UVA). Also the effect of UV pretreatment on membrane fouling was investigated for microfiltration (MF) and reverse osmosis (RO) processes. The pretreatment of membranes using LUV or PUV was effective to control fouling of hollow fiber MF membranes. This is probably because of the reduction and modification of organics after UV treatments. However, the effect of UV pretreatment on RO flux was less significant, which is attributed to low fouling prophecy after MF treatment.


Author(s):  
Li-Wei Luo ◽  
Yin-Hu Wu ◽  
Yun-Hong Wang ◽  
Xin Tong ◽  
Yuan Bai ◽  
...  

Abstract The reverse osmosis (RO) system is widely applied to produce reclaimed water for high-standard industrial use. Chlorine disinfection is the main biofouling control method in the RO systems for wastewater reclamation. However, researchers reported the adverse effects of chlorine disinfection which aggravated biofouling in laboratory-scale RO systems. In this study, four parallel 4-inch spiral wound RO membranes were used to study the effect of chlorine on biofouling in a pilot-scale RO system. The free chlorine dosages in four experimental groups were 0, 1, 2 and 5 mg/L, respectively. After continuous chlorination and dechlorination, the feed water entered the RO system. It was found that chlorine pretreatment caused a 1.9–36.7% increase in relative feed water pressure of the RO system, suggesting that chlorine aggravated the membrane fouling in the pilot-scale RO system. The microbial community structures of living bacteria in the feed water of the RO system were determined by the PMA (propidium monoazide)-PCR method and showed that the relative abundance of chlorine-resistant bacteria (CRB) was significantly increased after disinfection. Nine major genera which maintained higher relative abundance in experimental groups with high chlorine dosage were considered as possible key species causing membrane fouling, including Pedobacter, Clostridium and Bradyrhizobium.


2002 ◽  
Vol 45 (1) ◽  
pp. 117-125 ◽  
Author(s):  
J.B. Downing ◽  
E. Bracco ◽  
F.B. Green ◽  
A.Y. Ku ◽  
T.J. Lundquist ◽  
...  

The sustainability of wastewater reclamation and reuse schemes is often limited by the increase in salt concentration that occurs with each water use. In this pilot study, we show that the cost of reclaiming wastewater and removing salt can be dramatically decreased by integrating recent advances in wastewater pond design, solids separation equipment, and membrane technology. Effluent from an AIWPS® Facility was clarified in a Krofta® SupracellTM Dissolved Air Flotation (DAF) unit and a Slow Sand Filter (SSF) prior to final treatment in an Expertise S.r.l. reverse osmosis (RO) unit. The ponds of the AIWPS® Facility removed an average of 82% of soluble BOD and 80% of soluble nitrogen. Following clarification, filtration, and RO treatment, the pollutant removals were > 99% for soluble BOD, > 99% for soluble nitrogen, and 98% for TDS. Based on membrane fouling rate data, the cleaning interval for the RO membranes in a full-scale AIWPS®-RO Facility would be over 100 days. This interval is on par with that typically seen in full-scale reclamation facilities treating secondary activated sludge effluent with microfiltration prior to reverse osmosis. A 4-MLD AIWPS®-RO Facility is expected to produce permeate water at substantially lower cost and lower energy consumption (US $698 and 443 kWh per million liters treated) than a system of equal capacity using conventional activated sludge secondary treatment followed by microfiltration and reverse osmosis (US $1274 and 911 kWh per million litres treated). This cost and energy differential is attributable to the lower capital and operating expenses of the AIWPS® Technology in comparison with activated sludge.


1975 ◽  
Vol 10 (1) ◽  
pp. 101-109
Author(s):  
H. Kirk Johnston ◽  
H.S. Lim

Abstract The suitability of reverse osmosis as a renovation technique for the treatment of municipal wastewaters has been assessed. Cellulose acetate membranes capable of 70% and 90% NaCl rejections were employed in both laboratory and pilot plant studies to evaluate the efficiency of this technique in removing the residual precipitant chemicals generally employed in phosphorus removal programs (iron chloride, alum, and lime) and the nutrients (phosphates, nitrates and ammonia) characteristic of municipal wastewaters. Secondary sewage and raw sewage as well as prepared nutrient solutions were employed in the course of this program. Both laboratory and pilot plant studies indicated consistently outstanding removal efficiencies for the species examined, almost independent of the nature of the waste solutions being treated. Permeation of the purified effluent was subject to significant reductions due to membrane fouling. This characteristic was most pronounced for the more permeable (less selective) membranes. Routine chemical and physical cleanings enable satisfactory flux levels to be maintained, thereby suggesting that reverse osmosis may become a viable municipal waste treatment technique.


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