introduction w objectives: w check water distribution system in the university and determine...

Introduction

Objectives: Check water distribution system in the

university and determine contaminated point in the system to be treated.

Suggest appropriate treatment to eliminate the possible contamination

Introduction

Limitation of the Study: To investigate drinking water distribution

system in Islamic University by detection of primary indicator pathogenic bacteria of 220 sample and perform three chemical tests including dissolved oxygen, nitrate and chloride on each sample and PH measurements as physical parameter

Literature review

Introduction of water contaminations

Microbial contamination There are four main types of micro

organism that can contaminate drinking water:

Bacteria Virus Protozoa Fungi

Bacterial Contamination

• Water borne Disease can caused by different type of bacteria.

• Most of bacterial pathogen may found in distribution system illustrate in this table.

organism Major diseaseSalmonella typhi Typhoid fever Salmonella paratyphi Paratyphoid fever

Salmonella typhimurium gastroenteritis

Other salmonella sp. Gastroenteritis(salmonellosis)

Shigella Bacillary dysentery

Vibro cholerae cholera

Enterovirulent E.coli gastroenteritis

Yersinia enterocolitica gastroenteritis

Campylobacter jejuni gastroenteritis

Legionella pneumophila Legionnaires disease, Pontiac fever

Virus Contamination

Water may also play a role in the transmission of virus with different mode of action such as: Hepatitis A and B virus, Rotavirus and others.

Others include: Poliovirus : poliomyelitis Enteric adenoviruses: gastroenteritis Hepatitis E : liver inflammation

Protozoa Contamination:

Giardia lamblia, cryptosporidium parvum and Entamoeba histolytica are the major intestinal protozoal pathogens that contaminate drinking water.

Primary Indication of Contamination

The organisms most commonly used as primary bacterial indicators of faecal pollution are the coliform group which .

are: Member of Family Enterobacteriace. Non spore forming bacteria Can ferment lactose at 35-37ºC

Total coliform bacteria


The total coliform bacteria group includes both faecal and environmental species which include:

Escherichia coli. Citrobacter. Klebsiella. Enterobacter.

Bacterial fecal indicator should be:• Abundant in faeces and sewage.

• Absent or at least very small in

• number from all other sources.

• Capable of isolation and identification easly.


These Organisms can survive and grow in water distribution system, they can be used as:

Indictor of treatment effectiveness.

To assess the cleanliness and integrity of distribution system and the potential presence of biofilms.

Faecal coliform

E. coli is the predominant coliform in faeces and the only member of the coliform group exclusively associated with faeces.

Other organisms can also be used as indicator of faecal pollution such as:

Faecal streptococci. Clostridium perferingens.

Biofilm in Distribution System Many different microbes have demonstrated

the ability to survive in the distribution system with some possessing the ability to grow and produce biofilms.

Water distribution system biofilm is a complex mixture of microbes organic and inorganic material accumulated amidst a microbially produced organic polymer matrix attached to the inner surface of the distribution system.

Steps of biofilm development:

Trace organic material deposits on water/solid interface forming conditioning layer which allow initial attachment of material cell.

Planktonic (free floating) bacteria approach the pipe wall and become entrained with in the boundary layer where flow velocity falls to zero result in reversible adsorption.

Some of reversibly adsorbed cells may permanently adhere the cell to the surface and become irreversibly adsorbed.

Biofilm bacteria excrete extra cellular polymeric substance (sticky polymers) which :

Hold the biofilm together. Act as nutrients for bacterial growth. Protect bacteria from biocides.

Chemical contaminationchemical contaminant of drinking water are often considered a lower priority than microbial contaminants.

Nitrate: Excessive concentration of nitrate in

drinking water can be hazardous of health, especially for infants.

Methmoglobinemia result from high concentration of nitrate.

Major chemical contaminant:

Chloride

Chloride in drinking water is generally not harmful to human beings until high concentration are reached, although it may be harmful to some people suffering from heart or kidney disease

Other health effect chemical contaminants: Fluoride Sodium Arsenic Lead

Literature reviewTreatment of water contamination.

Sanitization MethodOf bacteria

Oxidizing biocides Non oxidizing biocides

Physical Treatment

---Heat

-Mechanical removal

-Quaternay

- ammonium compounds.

-Anionic and nonionic surface active agent.

-Chlorine

-Chlorine dioxide

-Ozone

Methodology

MethodologyMethodology

This is microbiologically and chemically study to detect the quality of water distribution system.

Type of sample Number of sample before treatment

Number of sample after treatment

Municipality source 4 -

Well source 2 -

Central filter 2 2

Reservoir (mun) 37 7

Reservoir (filter) 20 6

Kitchen (mun) 9 -

Kitchen (filter) 23 7

Refrigerator 30 9

bath 39 -

Lab 12 -

Other 10 0

Total 188 31

Distribution of samples:



Sampling collection

Collection of sample is vary depend on the type of the source of water .Sampling from Taps- Flaming the tap by 70% ethanol saturated cotton swab. - Water was allowed to run for at least 2-3 minutes in order to flush

refrigerator for sample collection


Reservoirs Sample Collection

- Sterilization of outer surface of bottle by 70% ethanol

- Dipping of sterilized bottle inside reservoirs using long forceps.


Well Sample Collection

- Collection from well was performed after sterilization of nearest tap water before water passes into reservoirs.

Central Filter Sample Collection

- Sterilization of plastic tap filter with 70% ethanol. - Water were allowed to run for 5 minutes before the sample was taken.


Microbiological analysisMedia and Reagent

- Nutrient Agar-Endo-media

Total plate count analysis

- 100µl of sample were spread on NA by L- shaped glass rod.- Incubation at 37C for 24 hr before counts was done.- Colonies were counted as CFU/100ml.


Total Coliform

Membrane Filtration Method:

-Filtration of 100 ml water sample on membrane filter.

-Picked up filter paper on specified media.

- Incubation at 37C for for 24hr


- Pink colony counted as presumptive total coliform.

-Green metallic colony counted as presumptive E.coli.


Chemical and Physical Analysis

Nitrate AnalysisUltraviolet spectrophotometric method used for nitrate determination.Chloride AnalysisSilver nitrate titration was performed to determine

chloride concentration as mg/l.

silver nitrate titration for chloride determination


PH Measurement

Using pH meter

Dissolved Oxygen

Using DO meter

Result and Discussion

Microbiological Analysis

Microbiological analysisTotal plate count (TPC) The range of TPC in

tested samples varied from as low as 1000CFU/100ml to TNTC ,with the exception of 14 samples which did not show any growth.

TPC value increased were water flow from main sources to finished taps.

Total plate count (TPC)

Some pathogenic bacteria with distinctive appearance were isolated and defined from some samples, such as Serratia and Pseudomonas auroginosa

Red colonies of Serratia were observed on NA in filter reservoir sample


Green colony of Pseudomonas auroginosa observed on NA in different samples


It observed that highest levels of TPC correlated with the age of building; older building such as (teeba, admission, medical service, student and academic affairs buildings) showed higher levels than new building.

TPC count CFU/100ml

Building L C TEEBA Administration

Minimum 0 0 4000 1000

Maximum 2000 4000 500*10³ 142*10³

Average 750 1285 303.4*10³ 31.5*10 ³


During the study period, some reservoirs in these building were found open or their cover not completely secure which indicate that there is a shortage of inspection to prevent such contamination that may result from dust or other sources (e.g., animals, insects and birds).

Total coliform (TC)

Samples collected showed that approximately 76% were contaminated with total coliform with a range varying from one CFU/100ml to TNTC. The rest of the samples (24%) were negative for Total coliform.

absance fromTC

contamination with TC

Total coliform (TC)

23% of all reservoirs sample were contaminated with TC

100% of all filter reservoir samples were contaminated with TC

33%of all municipality reservoir samples were contaminated with TC

contaminationwith tcabsance from tc

Total coliform (TC)

Highest main sources contamination observed in well. The following table illustrate total coliform levels in the three main sources in the university during the study period.

SOURCE TC count CFU/100ml

January February March

Municipality line(1) - 1 6

Municipality line(2) 4 - -

Well 4 8 13 -

Central filter 2 2 200

Total coliform (TC)

80% of refrigerator samples were contaminated with Total coliform, and only 20% of samples were negative for TC.

absanc fromTCcontaminationwith TC

Chemical Analysis

Chemical analysisChloride It observed that:It observed that: 93% of municipality samples did not comply with WHO 93% of municipality samples did not comply with WHO

standard, it exceeded 250mg/lstandard, it exceeded 250mg/l The following table summarize the result for filter and The following table summarize the result for filter and

mun samplesmun samples

mun filterMinimum 115 22Maximum 572 355Average 372.7 75.5

Standard deviation 68.38 40.4

Geometric mean 365.5 68.82

Chloride

Lowest percentage failure chloride were found in N and D building, while highest percentage failure were found in E and C building.

Central filter has the ability to decrease 70% of chloride concentration from the main sources

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C L N D E

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1 2 3 4 5 6 7 8 9

pp

m

Nitrate analysis:

The efficiency of central filter to decease nitrate concentration is about 40%.

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60

70

1 2 3 4 5 6 7 8 9

pp

m

1: mean of reservoir before filtration.2: central filter, 3: mean of reservoir

after filtration, 4: filter out let (kitchen) D500

5:D400, 6:D300, 7:D200, 8:D100, 9:D000

Nitrate analysis:

Summarize of nitrate result for filter and municipality samples illustrate in this table:

MUN FILTER

Minimum 41.75 15.07

Maximum 120.6 82.34

Average 69.03 36.33



PH

For all samples were tested for PH measurement, results were showed in normal range according to Palestinian standard (6.5-8.5).

Summary of pH result for filter and mun samples

MUN FILTER

Minimum 6.8 7.05

Maximum 8.4 8.21

Average 7.83 7.53



Dissolved oxygen

Dissolved oxygen measurement results were showed significant change for all samples, and this variation may be due to change in temperature during study period.

Normal range for DO is (6-8ppm) summary of DO result for filter and municipality samples

MUN FILTER

Minimum 3.4 2.8

Maximum 11.4 11.7

Average 6.15 6.06



Analysis and Correlation of Microbial and Chemical test

Analysis and correlation of microbial and chemical test

In this study tests were performed showed different correlation between chemical and microbial analysis results.

0

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C L N D E

%TC%nitrate>70%CL

Analysis and correlation of microbial and chemical test

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120

1 2 3 4 5 6 7 8

pp

m

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

CFU/

100m

l

nitrate

TPC

1: reservoir (main)2: E: 507 bath, 3:407, 4: E307, 5: E207, 6:E: 107, 7: E007

Analysis and correlation of microbial and chemical test Correlation between TPC and nitrate

concentration in C-building (mun)

050010001500

2000250030003500

1234567

CFU/

100m

l

0

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pp

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TPC

nitrate

1: mun source, 2: reservoir (mun), 3: mun out let C5011 4: C401, 5: C301, 6: C101

Result

After Treatment

Result after treatment Randomly collected samples were re-tested to measure the efficacy of water treatment and the integrity of the distribution system

Treated units were retested showed an elevation of total coliform and total plate count per 100 ml, and related changes in nitrate concentration.

This elevation may be due to many reasons including:

Inadequate or insufficient treatment were applied

Biofilm sloughing from pipes.

Disinfectant resistant may be another cause of increase the contamination after treatment.

Tc of ref samples before and after treatment

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100

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400

1234567

ref sample

tc

tc*

The following figure show the correlation between chloride and nitrate concentration and total coliform count were tested for refrigerator sample after treatment

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TC nitrate cl beforeafter

Total coliform, nitrate and chloride concentration in refrigerator sample (N100)

Total coliform, nitrate, and chloride concentration in central filter

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100

150

200

250

1 2 3nitratetccl

1: Central filter before treatment2: Central filter after treatment3: Central filter after change the station

Conclusion and Recommendation


It is not meaningful or practicable to strive for a sterile drinking-water network devoid of all microorganisms. The principal objective is to remove pathogenic organisms from the water supply and prevent contamination during distribution system.

Chemical, physical and microbial parameter should meet WHO and Palestinian standard to avoid adverse health effect that may cause for consumers.


The result in this research showed high average number of heterotrophic plate count and total coliform in drinking water and this is not safe for students and workers consumption as its levels of contamination are high and exceed by far the allowable limits, and this poses a health risk for the consumers.

The High regrowth of heterotrophs and total coliform

occurring after chlorination indicates the inefficiency of chlorination steps or the levels of chlorine in treated water were low.


The occurrence of bacterial regrowth within distribution system is dependent upon a complex interaction of chemical, physical and operational parameters. No single factor could account for all the coliform occurrences, all these parameter in devising a solution to regrowth problem must be considered.


Sanitary inspections should be carried out regularly by specialist worker on all water distribution system in university and not merely the points were analyzed.

Periodically maintenance of Reverse Osmosis purification system should be taken to check the efficiency of R\O in filtration of water to prevent microbial contamination that may be occurred in the distribution system.


Educate students for good use of the refrigerators which is used for drinking in the university and use it carefully with good hygiene to prevent contamination that may be occur inside

Thanks TO

Dr.Abdelraouf Elmanama

Medical Technology Department

Environmental and Rural Research Center

Administration of University

introduction w objectives: w check water distribution system in the university and determine...

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