Effect of source water quality on solar disinfection rate under multiple experimental conditions

2014 ◽  
Vol 4 (4) ◽  
pp. 714-719
Author(s):  
M. Mansoor Ahammed ◽  
Shilpa Dave
Keyword(s):  
Natural Waters ◽  
Municipal Wastewater ◽  
Heterotrophic Bacteria ◽  
Exposure Period ◽  
Most Probable Number ◽  
Experimental Conditions ◽  
Probable Number ◽  
Solar Disinfection ◽  
Complete Inactivation ◽  
Naturally Occurring

Water samples from four different sources of varying physico-chemical and microbial quality with their naturally occurring microorganisms were exposed to sunlight in polyethylene terephthalate bottles under similar conditions. Up to 3-log10 reduction of total coliforms (TC) was observed during a 6-h exposure period under weak/moderate radiation conditions (<600 W/m2). Complete inactivation of TC was not achieved in 6 h of exposure for waters with larger initial TC such as river water (1 × 103 most probable number [MPN]/100 mL) and treated municipal wastewater (2 × 105 MPN/100 mL) under these conditions. Heterotrophic bacteria showed lower inactivation rates than did TC. The inactivation rate for spiked Escherichia coli was faster than for naturally occurring coliforms. Further tests with compound parabolic collectors showed that complete inactivation of naturally occurring TC could be achieved within 6 h of exposure for all the natural waters tested. The results of the study thus indicate the need to use naturally occurring organisms in testing the effectiveness of solar disinfection, and the importance of source quality on the inactivation rates of microorganisms.

Solar disinfection for household treatment of roof-harvested rainwater

2008 ◽  
Vol 8 (2) ◽  
pp. 153-160 ◽  
Author(s):  
V. Meera ◽  
M. M. Ahammed
Keyword(s):  
Prolonged Exposure ◽  
Heterotrophic Bacteria ◽  
Inactivation Kinetics ◽  
Bacterial Inactivation ◽  
Solar Disinfection ◽  
Complete Inactivation ◽  
Naturally Occurring ◽  
Significant Difference ◽  
Solar Intensity ◽  
Inactivation Efficiency

The effectiveness of solar disinfection in treating roof-harvested rainwater contaminated with microorganisms was evaluated with a view to its use as a household technology. Coliform and heterotrophic bacteria inactivation kinetics were studied using bottles with different backing surfaces. The effects of various parameters such as turbidity, solar intensity, type of organisms (naturally occurring versus laboratory grown) and bottle volume on bacterial inactivation were studied. Complete inactivation of total coliforms was observed in 6 h when solar radiation exceeded ∼500 W/m2.Under high contamination and overcast conditions, prolonged exposure was needed. Moderate turbidity (38 NTU) did not reduce the inactivation efficiency, but slightly enhanced it. No regrowth of microorganisms was observed after 24 h following solar disinfection. No significant difference in the inactivation kinetics was observed for bottle sizes in the range of 0.5 to 2.0 L. Tests with naturally occurring and laboratory-grown organisms indicated that laboratory-grown organisms were inactivated faster than naturally occurring organisms.

scholarly journals Influence of environmental disturbances on the bacteriological quality of Pagbanganan river in Baybay City, Leyte, Philippines

2019 ◽  
pp. 81-91 ◽  
Keyword(s):  
Water Quality ◽  
Water Column ◽  
Heterotrophic Bacteria ◽  
Freshwater Ecosystems ◽  
Most Probable Number ◽  
Public Water Supply ◽  
Environmental Disturbances ◽  
Probable Number ◽  
Fermentation Test

Microorganisms like bacteria are frequently used as indicators of water quality in freshwater ecosystems. Thus, this study was conducted to evaluate the total coliforms (TC) and total aerobic heterotrophic bacteria (TAHB) present in the upstream (Kantagnos), midstream (lgang), and downstream (Kan-ipa) of Pagbanganan River. The most probable number (MPN/100 mL) of TC was determined through multiple tube fermentation test while counts of TAHB present in both water and sediments were enumerated by serial dilution and plating methods. MPN of TC revealed that the river water should not be used as a source of public water supply and as a venue for contact recreational activities like bathing and swimming. Furthermore, TAHB in the sediments of the river did not differ significantly across sites although their values showed a decreasing trend. Conversely, TAHB in the water column of the river significantly increased from upstream to downstream. These results are most probably influenced by the quarrying activities present in the area. In the upstream where there is no quarrying activity, TAHB was higher in sediment than in the water, while in the downstream where quarrying activities are present, it is otherwise. Because of these significant differences, it is believed that the ratios of TAHB present in the water column and sediments are potential indicators of sediment disturbance in the aquatic environment. The results of this study imply that proper management of Pagbanganan River by all sectors of the community is needed to keep it sustainable for safe use.

scholarly journals Bacteria and protozoa populations in groundwater in landfill area in São Carlos, SP

1999 ◽  
Vol 30 (3) ◽  
pp. 196-202 ◽  
Author(s):  
Roberta Fusconi ◽  
Mirna Januária Leal Godinho
Keyword(s):  
Heterotrophic Bacteria ◽  
Mean Value ◽  
Microbial Populations ◽  
Most Probable Number ◽  
Plate Method ◽  
Probable Number ◽  
Mean Values ◽  
The Mean ◽  
The Town ◽  
Microaerophilic Conditions

The microbial populations of groundwaters were analyzed in a region under the influence of a landfill (piezometer L12) in the town of São Carlos, São Paulo, Brazil, and in an area not influenced by the landfill (piezometer L5). Heterotrophic bacteria were counted by spread plate method and the number of protozoa was estimated by the most probable number method. There was a larger number of organisms in well L12, with a mean value of 15.76 x 104 CFU/ml for bacteria and 9.7 MPN/ml for protozoa, whereas the mean values for piezometer L5 were 2.88 x 104 CFU/ml for bacteria and 3.4 MPN/ml for protozoa. The greater abundance detected in piezometer L12 may be related to the influence of the leachate through the landfill on the microbial populations, also demonstrated by deoxygenation and by the high conductivity values (3530 µS/cm) compared to piezometer L5 (2.47 mg/L dissolved oxygen and 42 µS/cm conductivity). The most commonly detected protozoa were amoebae and flagellates. The density of flagellate protozoa determined under microaerophilic conditions was 10 times higher than that determined under aerobic conditions.

Investigation of Bacterial Populations Producing Elevated MPN Values and False Positive Fecal Coliform Counts and Applicable Disinfectants in an Industrial Wastewater

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2181-2182 ◽  
Author(s):  
E. M. Davis ◽  
D. L. Manville ◽  
J. J. Mathewson ◽  
G. W. Meriwether
Keyword(s):  
Fecal Coliform ◽  
Municipal Wastewater ◽  
Waste Treatment ◽  
Treatment Plant ◽  
Paper Mill ◽  
Most Probable Number ◽  
Pulp And Paper Mill ◽  
Klebsiella Species ◽  
Bacterial Populations ◽  
Probable Number

This poster presents data on the types of bacteria which produced elevated, most probable number (MPN) fecal coliform values in an industrial waste treatment plant effluent. The principal influent stream, a pulp and paper mill wastewater, contained principally Klebsiella species of environmental, not enteric origin. Fecal streptococci and enterococci were low in numbers. Eight disinfectants were tested on a small (currently acid disinfected) municipal wastewater incoming stream and on the main plant effluent.

scholarly journals Double-Layer Plaque Assay for Quantification of Enteroviruses

2004 ◽  
Vol 70 (5) ◽  
pp. 2801-2805 ◽  
Author(s):  
Laura Mocé-Llivina ◽  
Francisco Lucena ◽  
Juan Jofre
Keyword(s):  
Double Layer ◽  
Carcinoma Cell ◽  
Plaque Assay ◽  
Most Probable Number ◽  
Suspended Cell ◽  
Probable Number ◽  
Membrane Filters ◽  
Naturally Occurring ◽  
Order Of Magnitude ◽  
Virus Quantification

ABSTRACT We describe here a double-layer plaque assay for the quantification of enteroviruses, combining a monolayer plaque assay and a suspended-cell plaque assay. The double-layer assay provides significantly greater counts than other methods of virus quantification of both suspensions of pure culture viruses and naturally occurring viruses. The counts obtained by this method are approximately one order of magnitude greater than those obtained with the more commonly used method, the monolayer plaque assay. We conclude that the methods available for quantifying viruses rank in efficiency as follows: double-layer plaque assay ≥ suspended-cell plaque assay > counting cytopathogenic virus adsorbed to cellulose nitrate membrane filters ≥ most probable number of cytopathogenic units > monolayer plaque assay. Moreover, the double-layer plaque assay allows the use of two different cell lines in the two layers. Using the human colonic carcinoma cell line CaCo2 facilitates the recovery of a greater number and diversity of naturally occurring enteroviruses in water than the monolayer agar method. In addition, the pretreatment of cells with 5-iodo-2′-deoxyuridine (IDU) prior to the quantification of enteroviruses by the double-layer plaque assay provides significantly higher recoveries than the use of IDU does with the other methods of quantification.

scholarly journals ANTIMICROBIAL EFFICACY OF SOLAR DISINFECTION OF SELECTED DRINKING WELL WATER IN BENIN CITY, NIGERIA

2021 ◽  
Vol 2 (1) ◽  
pp. 16-25
Author(s):  
S. K. Adebiyi ◽  
E. Emoresele ◽  
M. J. Ogbonnaya
Keyword(s):  
Antibiotic Susceptibility ◽  
Fecal Coliforms ◽  
Antimicrobial Efficacy ◽  
Most Probable Number ◽  
Well Water ◽  
Fecal Indicators ◽  
Probable Number ◽  
Solar Disinfection ◽  
Benin City ◽  
Pet Bottles

Solar Disinfection (SODIS) has been identified as a relatively cheap method of purifying water against pathogens, therefore providing potable drinking water, an essential component upon which living systems and the human body depends. In this study, the antimicrobial efficacy of solar disinfection of drinking well water was studied. A total of thirty (30) wells was randomly sampled from six (6) local government areas in Benin City, based on accessibility and communal usage. The well water was sampled using transparent 1L polyethylene terephthalate (PET) bottles. Standard microbiological and biochemical test procedures were performed to enumerate, isolate, characterize and identify the isolates to genus level. Antibiotic susceptibility of the isolate was also ascertained. Coliform test was conducted and counts expressed in Most Probable Number (MPN). The study revealed that Staphylococcus sp., Micrococcus sp., and Klebsiella sp. and, Penicillium sp., Fusarium sp. and Candida sp. were the most prevalent heterotrophic bacteria and fungi isolates in the study area in addition to fecal indicators (Escherichia coli and Fecal streptococci) with 83.33% occurrences respectively. The study also revealed that the overall percentage elimination of the identified isolates was recorded as 42.11%, while the percentage elimination of fecal indicators identified was 50%. It was observed that SODIS was very efficacious with a percentage reduction of above 95% for all identified isolates. It was also observed that SODIS is slightly more bactericidal as compared to its being fungicidal. From the study, it could not be ascertained with certainty whether or not, exposure to SODIS alters a microbial pathogens’ antibiotic susceptibility. The use of SODIS did not completely eliminate all the fecal coliforms found in the studied well water, therefore making it unfit for drinking with regards to WHO recommendation. Consequently, the study recommends the use of SODIS only in conjunction with other water purification methods to ensure potability.

scholarly journals Impact of Blackwater Disposal in Erbil City on Municipal Wastewater and Bounded Soil Characteristics with Potential Solutions

2021 ◽  
Keyword(s):  
Municipal Wastewater ◽  
Ammonia Oxidation ◽  
Oxygen Demand ◽  
Soil Characteristics ◽  
Soil Samples ◽  
Disposal Site ◽  
Most Probable Number ◽  
Oil And Grease ◽  
Probable Number ◽  
The Impact

<p>Direct discharge of black water (BW) without treatment to the natural environment causes problems for the environment. The present research aimed to examine the impact of direct disposal of BW on the municipal wastewater (MWW) and surrounded soil characteristics in the BW disposal site in Erbil City- Kurdistan Region (KR), Iraq. To check the effect of BW on the boarded MWW and the soil; BW, MWW, BW mixed with MWW (BWMWW), polluted soil, and clean soil samples were collected and analyzed. Samples of BW, MWW, and BWMWW were tested for 32 physical-chemical and biological quality parameters such as pH, turbidity, solids, color, dissolved oxygen, five day biochemical oxygen demand (BOD5), chemical oxygen demand (COD), ammonia, oxidation-reduction potential (ORP), sulphate, oil and grease, phosphate, Most probable number (M.P.N.) of coliform, Thermo tolerant, M.P.N. E.Coli …etc. In contrast, soil samples were tested for 37 parameters, for instance pH, ORP, organic matter (OM), sulfite, Titanium, Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel, Copper, Zinc, Gallium, Arsenic, Rubidium, Strontium, Yttrium, Zirconium, Molybdenum, Silver, Cadmium, Mercury, Lead, Thorium and Uranium. Results revealed that the direct disposal of BW without treatment commonly affected on the MWW and the surrounded soil characteristics. Potential treatment processes and solutions for BW disposal were presented.</p>

Neural Network Model for Survival and Growth of Salmonella enterica Serotype 8,20:–:z6 in Ground Chicken Thigh Meat during Cold Storage: Extrapolation to Other Serotypes†

2015 ◽  
Vol 78 (10) ◽  
pp. 1819-1827 ◽  
Author(s):  
T. P. OSCAR
Keyword(s):  
Neural Network ◽  
Network Model ◽  
Cold Storage ◽  
Neural Network Model ◽  
Salmonella Enterica ◽  
Most Probable Number ◽  
Experimental Conditions ◽  
Probable Number ◽  
Survival And Growth ◽  
Hidden Layer

Mathematical models that predict the behavior of human bacterial pathogens in food are valuable tools for assessing and managing this risk to public health. A study was undertaken to develop a model for predicting the behavior of Salmonella enterica serotype 8,20:–:z6 in chicken meat during cold storage and to determine how well the model would predict the behavior of other serotypes of Salmonella stored under the same conditions. To develop the model, ground chicken thigh meat (0.75 cm3) was inoculated with 1.7 log Salmonella 8,20:–:z6 and then stored for 0 to 8 days at −8 to 16°C. An automated miniaturized most-probable-number (MPN) method was developed and used for the enumeration of Salmonella. Commercial software (Excel and the add-in program NeuralTools) was used to develop a multilayer feedforward neural network model with one hidden layer of two nodes. The performance of the model was evaluated using the acceptable prediction zone (APZ) method. The number of Salmonella in ground chicken thigh meat stayed the same (P &gt; 0.05) during 8 days of storage at −8 to 8°C but increased (P &lt; 0.05) during storage at 9°C (+0.6 log) to 16°C (+5.1 log). The proportion of residual values (observed minus predicted values) in an APZ (pAPZ) from −1 log (fail-safe) to 0.5 log (fail-dangerous) was 0.939 for the data (n = 426 log MPN values) used in the development of the model. The model had a pAPZ of 0.944 or 0.954 when it was extrapolated to test data (n = 108 log MPN per serotype) for other serotypes (S. enterica serotype Typhimurium var 5−, Kentucky, Typhimurium, and Thompson) of Salmonella in ground chicken thigh meat stored for 0 to 8 days at −4, 4, 12, or 16°C under the same experimental conditions. A pAPZ of ≥0.7 indicates that a model provides predictions with acceptable bias and accuracy. Thus, the results indicated that the model provided valid predictions of the survival and growth of Salmonella 8,20:–:z6 in ground chicken thigh meat stored for 0 to 8 days at −8 to 16°C and that the model was validated for extrapolation to four other serotypes of Salmonella.

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