Biocidal efficacy of monochloramine against biofilm bacteria

Rao, T. Subba; Nancharaiah, Y.V.; Nair, K.V.K.

doi:10.1080/08927019809378363

Cited by 19 publications

(14 citation statements)

References 25 publications

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“…Epifluorescence direct counting method (AODCacridine orange direct counting) was used to assay the total bacterial population in the biofilms (Rao et al 1998), the bacterial count was represented as cells cm -2 . Biofilm samples on plexiglas panels (7 9 3 9 0.3 cm) were stained with 4,6-diamidino-2-phenylindole (DAPI, 10 lg ml -1 ) for 10 min and acridine orange (0.1% solution in distilled water) for 5 min (Parsons et al 1992).…”

Section: Microbiological Studiesmentioning

confidence: 99%

Comparative effect of temperature on biofilm formation in natural and modified marine environment

Rao

2009

Aquat Ecol

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Progression of biofilm formation was monitored at two stations near a nuclear power plant, Kalpakkam, located near coastal waters of Bay of Bengal. These stations are natural marine environment, station 1; and the condenser outfall area of the power plant the modified marine environment station 2. The biofilm formed on plexiglas panels was analysed in triplicates at 24 h intervals for various physical, chemical and biological parameters for 120 h (5 days). The biofilm formation showed both temporal and spatial variation in various parameters assayed. Among the water-quality parameters analysed, seawater temperature showed significant increase (*5°C) at station 2. The increase in water temperature enhanced the metabolism and influenced most of the biofilm parameters assayed at station 2. Biofilm formed at station 2 was very thick (113 lm) than that of at station 1 (22 lm). The distribution of parameters like biofilm thickness, biomass, chlorophyll a, particulate organic carbon, hexose sugar and diatom counts showed similar trend (i.e., a sharp increase after 96 h of biofilm growth) in the biofilm formed at station 2. Moderately high ammonia levels (44 lg l -1 ) were detected in the biofilm formed at station 2. The biofilm microbiota was diverse at both the stations: it constituted bacteria [nitrate reducers (NRB), ammonia oxidizers (AOB) and culturable aerobic heterotrophic bacteria (CAHB)], algae and macrofoulants. The various bacterial types assayed showed a population range from 10 2 to 10 6 cfu cm -2 . The final community after 120 h at station 1 comprised CAHB, NRB, diatoms, barnacle cyprids and juvenile bryozoans. At station 2, the biofilm initially consisted of CAHB, NRB and diatoms but after 120 h, AOB, cyanobacteria and filamentous algae were dominant. The plausible factors that influenced biofilm formation were temperature, nutrients and organic matter. The biofilm phenomenon in natural and modified marine environment was hypothesized and discussed.

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Section: Microbiological Studiesmentioning

confidence: 99%

Comparative effect of temperature on biofilm formation in natural and modified marine environment

Rao

2009

Aquat Ecol

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“…The Environmental Pollution Prevention Agreement in Japan stipulates that residual chlorine levels at industrial outfalls must not be detectable. At times, significant ammonia levels in cooling water make biofouling control with chlorine difficult, since these result in the formation of chloramines and chloroorganics, which are toxic to many organisms [21,57].…”

Section: Pulse Chlorinationmentioning

confidence: 99%

Biofouling in Industrial Water Systems

Toleti

2015

Mineral Scales and Deposits

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“…Turetgen (2004) observed that monochloramine was significantly more effective than free chlorine against cooling tower biofilms. Rao et al (1998) demonstrated that monochloramine and free chlorine showed similar biocidal activity in controlling biofilms and that monochloramine formed in situ in the cooling circuit could be as effective as free chlorine. Hence, chloramination that relies on the availability of ammonia in wastewater may be an effective biomass control option in cooling systems using secondary treated municipal wastewater as makeup.…”

Section: -54 | De-fc26-06nt42722mentioning

confidence: 99%

“…Rao et al (1998) demonstrated that monochloramine and free chlorine showed similar biocidal activity in controlling biofilms and that monochloramine formed in situ in the cooling circuit could be as effective as free chlorine. In cooling towers utilizing impaired waters, biofilm formation is one of the main concerns for effective tower operation.…”

Section: Introductionmentioning

confidence: 99%

Reuse of Treated Internal or External Wastewaters in the Cooling Systems of Coal-Based Thermoelectric Power Plants

Vidić¹,

Dzombak²,

Hsieh³

et al. 2009

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| DE-FC26-06NT42722Final Technical Report ABSTRACTThis study evaluated the feasibility of using three impaired waters -secondary treated municipal wastewater, passively treated abandoned mine drainage (AMD), and effluent from ash sedimentation ponds at power plants -for use as makeup water in recirculating cooling water systems at thermoelectric power plants. The evaluation included assessment of water availability based on proximity and relevant regulations as well as feasibility of managing cooling water quality with traditional chemical management schemes. Options for chemical treatment to prevent corrosion, scaling, and biofouling were identified through review of current practices, and were tested at bench and pilot-scale.Secondary treated wastewater is the most widely available impaired water that can serve as a reliable source of cooling water makeup. There are no federal regulations specifically related to impaired water reuse but a number of states have introduced regulations with primary focus on water aerosol "drift" emitted from cooling towers, which has the potential to contain elevated concentrations of chemicals and microorganisms and may pose health risk to the public.It was determined that corrosion, scaling, and biofouling can be controlled adequately in cooling systems using secondary treated municipal wastewater at 4-6 cycles of concentration.The high concentration of dissolved solids in treated AMD rendered difficulties in scaling inhibition and requires more comprehensive pretreatment and scaling controls. Addition of appropriate chemicals can adequately control corrosion, scaling and biological growth in ash transport water, which typically has the best water quality among the three waters evaluated in this study. The high TDS in the blowdown from pilot-scale testing units with both passively treated mine drainage and secondary treated municipal wastewater and the high sulfate concentration in the mine drainage blowdown water were identified as the main challenges for blowdown disposal. Membrane treatment (nanofiltration or reverse osmosis) can be employed to reduce TDS and sulfate concentrations to acceptable levels for reuse of the blowdown in the cooling systems as makeup water. ACKNOWLEDGEMENTS

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Biocidal efficacy of monochloramine against biofilm bacteria

Cited by 19 publications

References 25 publications

Comparative effect of temperature on biofilm formation in natural and modified marine environment

Comparative effect of temperature on biofilm formation in natural and modified marine environment

Biofouling in Industrial Water Systems

Reuse of Treated Internal or External Wastewaters in the Cooling Systems of Coal-Based Thermoelectric Power Plants

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