We studied the physical, chemical, and microbiological factors that influence drinking water quality processed from River Tigris, and of the three main drinking water purification stations located at different parts of Tigris River, along with evaluation of drinking water of Al-Shula region in Baghdad city. Water samples were taken monthly from December 2009 to September 2010. Physical and chemical analyses of water included determination of temperature, pH, turbidity, electrical conductivity, total dissolved solids, salinity, dissolved oxygen, and biological oxygen demand. The results of water before and after purification indicated values within the international allowable levels. Microbial analyses included estimation of the number of total viable microbial counts, total coliform, total fecal
Safety and quality of drinking water are always an important public health concern [
According to UNICEF report, about 800 million people in Asia and Africa are living without access to safe drinking water. Consequently this has caused many people to suffer from various diseases [
Contamination of water has been frequently found associated with transmission of diseases causing bacteria,
Comprehensive evaluations of microbial quality of water require survey of all the pathogens that have potential for human infections [
Water Quality Index (a single value indicator of the water quality) was analysed by Alobaidy et al. [
In Baghdad city there are seven water treatment stations located on the banks of the Tigris River along a distance of 50–60 km. These stations are Sharq Diglla station, Al-Karama station, Al-Wathba station, Al-Qadisia station, Al-Dorra station, Al-Wahda station, and Al-Rashed station. These stations are providing Baghdad with most of its water requirements.
In recent years several M.Sc. and Ph.D. theses have been conducted in Iraq concerning drinking water quality and the impacts of some of the bacteriological and ecological factors on the Tigris River [
The aim of this work is to study different parameters of drinking water that affect the health of people of Baghdad city. To perform this target, four factors were studied first, the microbiologic survey of different pathogens of water of Tigris River and of three water purification stations, Sharq Diglla, Al-Karama, and Al-Qadisia. Second aim was to study the physical and chemical factors that influence water quality of the Tigris River. Third aim was to evaluate the treatment efficiency of the 3 stations. The last aim was to evaluate drinking water of Al-Shula region in Baghdad city that is provided with water from Al-Karama purification station.
Baghdad has an area of 800 km2, and 65% of all the industrial institutions and factories were located in Baghdad. This condition generated ecological problems threatening the ecosystem of Baghdad city, due to the drainage of sewages and byproducts of these institutions and factories directly to the body of Tigris River [
The three purification stations were chosen according to their purification capacity and locations along the Tigris River. They provide Baghdad city with 910000 m3/day and comprise about 72% of all the 7 purification stations capacity present in Baghdad.
The station is located at the North of Baghdad and its purification capacity is about 650000 m3/day, it provides Al-Rusafa side of Baghdad with drinking water, and it comprises about 51% of the purification capacity of all the stations in Baghdad (Figure
The locations of the three purification stations in Baghdad province.
The station is located at the center of Baghdad and its purification capacity is about 160000 m3/day, it provides part of Al-Rusafa and part of Al-Karkh sides of Baghdad with drinking water, and it comprises about 13% of the purification capacity of all the stations in Baghdad (Figure
The station is located at the south of Baghdad and its purification capacity is about 100000 m3/day, and provides Al-Qadisia region with drinking water and it comprises about 8% of the purification capacity of all the stations in Baghdad (Figure
Duplicate sample of raw water from Tigris River and from stations after purification were taken every month from December 2009 to September 2010. Forty tap water samples were also taken from the houses of Al-Shula region during summer months, June, July, August, and September 2010.
Raw water samples were collected in clean sterilized glass bottles of 250 mL capacity from 20 to 30 cm under the surface of water of Tigris River from the point where it inters to the pipe of purification station. Drinking water samples from the station were also taken in sterilized bottles of 250 mL capacity. Forty 200 mL tap water sample were also taken from the houses of Al-Shula region after the sterilization of house faucet. All these bottles were closed carefully and transported to the laboratory on ice, and kept at 4°C, and processed within 6 hrs. Microbiological survey of water samples including total viable bacterial count were performed according to the general standard methods for examination of water and waste water [
Glass containers of 1 L capacity were used to collect raw water samples and drinking water from the stations faucets as described for bacteriological analyses, except for dissolved oxygen (DO) and biological oxygen demand (BOD) tests, dark glass container of 300 mL capacity were used. These containers were transported to the laboratory on ice and kept at 4°C and analyzed within 24 hrs. Chemical and physical measurements of the water samples were done as follows.
The temperature of the raw water of the Tigris River was measured by suspending a thermometer about 10 cm below the surface of water for at least 2 minutes before taking the reading, while the temperature of the stations water after purification were taken by putting the thermometer under the running water from the faucet for 5 minutes before taking the temperature [
The pH-meter (SCHOTT) was used.
Turbidity meter (SCHOTT) was used, the turbidity is expressed in Nephelometric Turbidity unit (NTU).
The conductivity meter (SCHOTT) was used, and the EC was determined according to the method described by Golterman et al. [
The Kondukto meter (SCHOTT) was used and the TDS is expressed in mg/L.
The (YSI model 54A) oxygen-meter was used to determine the D.O, and is expressed in mg/L.
The first reading of D.O was taken with oxygen meter and after 5 days of incubation of water samples in 20°C without light, the second reading of D.O was taken. The BOD was determined by the below equation and expressed in mg/L
The conductivity value was determined according to the method described in [
Statistical approaches, like LSD, ANOVA, Chi-square test, Kruskal-Wallis test, and correlation test for all the factors during the studied period and for the 3 stations, were done by analyzing the data (
In order to assess the water quality of a particular pond, stream or lake, we conducted tests to determine the level of dissolved oxygen, biological oxygen demand, nitrate, and phosphate in the water as well as the pH, temperature, and turbidity. These parameters along with the microbial contamination of water like total coliform and fecal
Common approach in determining amount of microbial safety of public water distribution system is based on sampling strategies in consumption point or water faucet [
Table
Confidence limit of GLM of all the variables studied with respect to seasons, months, stations, and replicate samples.
Variables studied | SOV |
|
|||||
---|---|---|---|---|---|---|---|
Corrected Model | Intercept | Season | Month | Station | REP | ||
Salinity (mg/L) of water of 3 stations | 0.00 | 0.00 | 0.00 | 0.00 | 0.01 | 0.74 | |
TDS (mg/L) of water of 3 stations | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.08 | 0.74 |
EC (microsemens) of water of 3 stations | 0.00 | 0.00 | 0.00 | 0.00 | 0.01 | 0.53 | 0.77 |
Turbidity NTU of water of 3 stations | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.43 | 0.41 |
pH of water of 3 stations | 0.01 | 0.00 | 0.15 | 0.34 | 0.00 | 0.53 | 0.22 |
No. of |
0.41 | 0.00 | 0.43 | 0.59 | 0.08 | 0.85 | 0.59 |
No. of |
0.00 | 0.00 | 0.00 | 0.01 | 0.96 | 0.57 | 0.59 |
Total coliform/100 mL of water of 3 stations | 0.00 | 0.00 | 0.00 | 0.01 | 0.96 | 0.57 | 0.71 |
Total number of bacteria of water of 3 stations | 0.00 | 0.00 | 0.00 | 0.00 | 0.22 | 0.26 | 0.59 |
Temperature °C of water of 3 stations | 0.00 | 0.00 | 0.00 | 0.00 | 0.01 | 0.81 | 0.99 |
Temperature °C of air | 0.00 | 0.00 | 0.00 | 0.00 | 0.16 | 0.98 | |
Temperature °C of water of Tigris River | 0.00 | 0.00 | 0.00 | 0.00 | 0.34 | 0.99 | |
BOD mg/L of water of Tigris River | 0.01 | 0.00 | 0.03 | 0.04 | 0.05 | 0.97 | 0.40 |
DO mg/L of water of Tigris River | 0.00 | 0.00 | 0.00 | 0.00 | 0.01 | 0.91 | 0.79 |
Salinity (mg/L) of water of Tigris River | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.69 | 0.67 |
TDS (mg/L) of water of Tigris River | 0.00 | 0.00 | 0.00 | 0.00 | 0.21 | 0.57 | 0.57 |
EC (microsiemens) of water of Tigris River | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.52 | 0.61 |
turbidity NTU of water of Tigris River | 0.00 | 0.00 | 0.00 | 0.70 | 0.00 | 0.47 | 0.50 |
pH of water of Tigris River | 0.01 | 0.00 | 0.01 | 0.02 | 0.18 | 0.30 | 0.42 |
No. of |
0.00 | 0.00 | 0.01 | 0.06 | 0.01 | 0.30 | 0.46 |
No. of |
0.00 | 0.00 | 0.00 | 0.02 | 0.00 | 0.78 | 0.55 |
Total no. of coliform/100 mL of water of Tigris River | 0.00 | 0.00 | 0.00 | 0.05 | 0.00 | 0.97 | 0.57 |
Total no. of bacteria/100 mL of water of Tigris River | 0.00 | 0.00 | 0.00 | 0.01 | 0.00 | 0.94 | 0.78 |
There was a high significant difference with respect to seasons and months, air, and raw water temperature,
No significant difference were recorded between seasons, months, and sites,
Data revealed turbidity values less than 5 NTU of drinking water in the stations. The turbidity of supply water is mostly used as a measure of water quality in water treatment plants. The desirable level less or equal to 1 NUT was recommended by WHO. Turbidity value up to 5 NUT will indicate inadequate efficiency of treatment plant and possibly correlate with increased total coliform bacteria [
Electrical conductivity in the aquatic ecosystem is considered to be a good indicator for evaluating total dissolved solid materials in water and nature of the purity of water [
Salinity and TDS have high significant difference with respect to seasons, months, and stations. The
D.O and BOD also have high significant difference with respect to seasons, months, and stations. The
Bacteriological analysis of water resources included total viable bacterial counts, total coliforms, total
Number and types of bacterial species isolated from different water sources.
Bacterial species | Number and types of bacterial species isolated from | M-Z test* | C.S. | ||
---|---|---|---|---|---|
Drinking water of Al-shula houses | Water of stations | Water of Tigris River | |||
|
8 | 10 | 30 | 0.885 | NS |
|
1 | 0 | 0 | 4.995 | NS |
|
0 | 0 | 1 | 0.749 | NS |
|
9 | 4 | 14 | 6.856 | S |
|
0 | 0 | 0 | — | — |
|
7 | 16 | 30 | 1.169 | NS |
|
1 | 1 | 2 | 0.207 | NS |
|
4 | 2 | 5 | 3.243 | NS |
|
0 | 1 | 1 | 0.824 | NS |
|
0 | 2 | 1 | 2.815 | NS |
|
0 | 2 | 2 | 1.666 | NS |
|
0 | 1 | 2 | 0.625 | NS |
|
0 | 3 | 1 | 5.309 | NS |
|
0 | 1 | 4 | 1.378 | NS |
|
0 | 0 | 0 | — | — |
|
0 | 0 | 1 | 0.742 | NS |
|
0 | 1 | 2 | 0.625 | NS |
|
0 | 0 | 3 | 2.251 | NS |
|
0 | 0 | 3 | 2.251 | NS |
|
0 | 1 | 1 | 0.824 | NS |
|
0 | 1 | 0 | 2.909 | NS |
| |||||
Total | 30 | 46 | 103 | 8.851** | S |
*Chi-Square test with 2 d.f. (
**Kruskal Wallis test recorded (Sig. at
For total coliform and fecal
In Tigris River water, on the other hand, the total coliform counts exceeded (1795–63000 CFU/100 mL) while the pathogenic fecal
The percentages of total coliform with respect to total viable bacterial count were 20.4% and 32% for cold and warm seasons, respectively while the percentages of fecal
On the other hand, the number and different bacterial species isolated from different water resources were also investigated (Table
The highest numbers of total coliform and fecal
Statistical analyses of the total coliform and fecal
95% confidence | Standard deviation | Mean | Sample | Months | Indicators | |
---|---|---|---|---|---|---|
Higher limit | Lower limit | |||||
0.36 | 0.00 | 0.35 | 0.11 | 10 | June | Total coliform |
1.11 | 0.00 | 0.78 | 0.55 | 10 | July | |
7.49 | 0.00 | 5.31 | 3.69 | 10 | August | |
1.85 | 0.15 | 1.19 | 1.00 | 10 | September | |
2.3 | 0.38 | 3.00 | 1.34 | 40 | Total | |
| ||||||
0.00 | 0.00 | 0.00 | 0.00 | 10 | June | Fecal |
0.72 | 0.00 | 0.70 | 0.22 | 10 | July | |
4.79 | 0.00 | 3.52 | 2.27 | 10 | August | |
1.68 | 0.00 | 1.26 | 0.78 | 10 | September | |
1.47 | 0.17 | 2.03 | 0.82 | 40 | Total |
Significant comparison (least sig. differences) of total coliform and fecal
September | August | July | Months | Indicators |
---|---|---|---|---|
0.475 | 0.006 | 0.723 | June | Total coliform |
0.717 | 0.015 | July | ||
0.036 | August | |||
| ||||
0.364 | 0.011 | 0.797 | June | Fecal |
0.514 | 0.021 | July | ||
0.088 | August |
It is noteworthy, however, that some fecal pathogens including many viruses and protozoa, may be more resistant to treatment by chlorine than the indicator bacteria [
According to the bacteriological data investigated in this research, it was possible to analyze the efficiency of the 3 stations according to the average total number of viable microbial agents in (raw water) and out (drinking water) of the purification units of the three stations using the following equation. Efficiency = output/input × 100, efficiency of Sharq Diglla station = 0.55 and it comprises 49%, efficiency of Al-Karama station = 0.16 and it comprises 14%, efficiency of Al-Qadisia station = 0.41 and it comprises 37%.
Accordingly, the efficiency of sharq Diglla station in purification process is better than both stations followed by Al-Qadisia station, then Al-Karama station Figure
The percentage of the efficiency of the 3 purification stations in Baghdad.
For raw water, the water quality showed high concentration of bacteria upstream to downstream of Tigris River. Physicochemical parameters, on the other hand, were within the acceptable values. This might be due to pollution of raw water from urban wastes and other sources. Treated water quality showed to be suitable but not good for public consumption in Sharq Diglla station (55%) efficiency and in Al-Qadisia station (41%) efficiency while it showed unacceptable water quality (14%) efficiency in Al-Karama station. These results were in accordance with the results obtained by Alobaidy et al. [
According to the results obtained, we conclude with the following. Total coliform counts and fecal Water quality in all water treatment stations with respect to temperature, pH, turbidity, salinity, and E.C are all within the water quality standards recommended by Iraqi and WHO standards except TDS. Total dissolved solids was increased in treated water than in river water. This could be due to the addition of Alum to the water during the coagulation process and to the absence of any chemical treatment unit in Baghdad water treatment process. The efficiency of Sharq-Diglla station in purification process is better than both Al-Qadisia and Al-Karama purification stations. Drinking water in Al-Shula region was not suitable for human consumption due to high contamination levels with Total coliform and Fecal The Authority of Baghdad Mayoralty should practice more efforts in controlling various procedures employed for treating and purification process in all the purification stations.