2.2.3 Water Quality of Groundwater and Surface Water

Transcription

1 The Study on Water Supply Systems in Mandalay City and in the Central Dry Zone Part II Study for Mandalay City Water Quality of Groundwater and Surface Water (1) Water Quality Standards for Drinking Water There are no nationwide water quality standards for drinking water in the Union of Myanmar. It seems that the Guideline for drinking water by WHO is applied provisionally as the nationwide water quality criteria for drinking water. Similarly, the water quality standard for drinking water in the Mandalay City is adopted from the WHO s guideline. The water quality standard for drinking water for MCDC (WQS-MCDC) is shown in Table 2.2.2, and WHO s guideline for drinking water quality 1 excluding organic constituents, disinfectants and disinfectant by-products, and radioactive constituents is shown in table 1. of Supporting 2-A Result of Water Quality Test. Table Water Quality Standard for Drinking Water for MCDC Water Quality Standard Items unit Desirable value Imperative value ph Color Units 5 50 Turbidity (F.T.U) F.T.U 5 25 Calcium (Ca) mg/l as Ca Total Hardness mg/l Magnesium (Mg) mg/l as Mg Chloride (Cl - ) mg/l as Cl Total Alkalinity mg/l Iron (Fe) mg/l Manganese (Mn) mg/l Sulfate (SO 4 2- ) mg/l Coliform (E.Coli) MPN 0 0 (2) Water Quality Survey by MCDC MCDC conducted water quality survey for groundwater and surface water from February 2000 to October Sampling points for groundwater were 35 stations including 27 tube wells for conventional water supply system and 6 tube wells for water supply system by communal tap. Remaining 2 stations were a well in the industrial zone and a test well. The 1 Guidelines for drinking-water quality second edition, Vol. 2, Health criteria and other supporting information, World Health Organization 2-33

2 The Study on Water Supply Systems in Mandalay City and in the Central Dry Zone Part II Study for Mandalay City results are shown in Table Most tube wells passed WQS-MCDC. However calcium of TW-14 and Total alkalinity of KOICA-19 and KOICA-9 exceeded WQS-MCDC. Sampling points of surface water were at the Ayeyarwaddy River near 22 nd street and the Ayeyarwaddy River in Shanglay Kyuw. Results shows that water quality of the Ayeyarwaddy River has no problem as water source for expanding of existing water supply system by MCDC. (3) Water Quality Survey by JICA The water quality survey for groundwater and surface water in the Mandalay City was conducted in this study. This survey has been conducted for 13 months shown in Fig Outline of water quality survey are itemized as below: Work (A) The water quality survey of groundwater and surface water. Work (B) Continuous measurement of 15 wells for 12 months. Work (C) Water quality analysis for a test well Work (D) Simultaneous measurement of 100 wells 1) Outline of Work (A) (i) Sampling Time First Sampling: 4 th June 2001 (Surface water 5, Groundwater 5 total 10 locations) Second Sampling: 18 th June 2001 (Groundwater 5 locations) (ii) Sampling points Sampling points are described below. See Fig Ground water in 5 tube wells (No.3, No.8, No.12, No.23, and No.27) Surface water in rivers Two points (candidate site for intake in the Ayeyarwaddy River.) A point (candidate site for intake in the Dotehtawaddy River.) Surface water in drainage canal Discharging point of wastewater into the Rivers (iii) Result Result of water quality survey regarding to Work (A) is shown in table 2.2.4(1/2) and 2.2.4(2/2). From the results of water quality by MCDC and JICA, the following knowledge is obtained. Evaluation of Groundwater Quality for Drinking Water 2-34

3 The Study on Water Supply Systems in Mandalay City and in the Central Dry Zone Part II Study for Mandalay City The water quality of production tube wells meets the criteria for drinking water except the concentration of calcium at the No.14 well. See Table Groundwater quality of No.14 tube well differs much from neighboring tube wells. Its reason is not clear, but the aquifer of No.14 tube well may be same as others because of short distance and same well depth. Therefore, it is presumed that there is contamination from upper aquifer or others. Therefore, monitoring of water quality for No14 tube well and of other aquifers including phreatic aquifer in neighboring wells is highly recommended. Evaluation of Surface Water Quality as Raw Water for Water Supply The quality of water of both the Ayeyarwaddy River and the Dotehtawaddy River is enough as the raw water subject to processing at a water treatment plant (WTP). However the Ayeyarwaddy River is more preferable to the Dotethawaddy River because TS and DS of the Dotethawaddy River are higher than those of the Ayeyarwaddy River. According to the results of water quality analysis and WQS-MCDC, the following treatment process is required for water supply using the river water. -To remove particulate matter: coagulation/flocculation, followed by sedimentation and filtration. -To disinfect of fecal bacteria and pathogens: disinfection Similarly, the concentration of color and iron in the Ayeyarwaddy River and the Dotehtawaddy River do not meet the WQS-MCDC. However, it is expected that the criteria for drinking water would be satisfied with removal of particulate matter. Evaluation of Pollution Load from Mandalay City The toilet wastewater (black water) in Mandalay City is treated by septic tank or pit latrine in principal, but most houses along some drainage canals discharge black water into there. Other wastewater (gray water), such as wastewater from kitchen, bathroom, laundry and others, is also discharged into the drainage canals without treatment. There are three main drainage canals in the City. The wastewater of western area is drained through Shwe Ta Chaung canal to the Ayeyarwaddy River via two pumping stations, which works during rainy season. The wastewater of eastern area is drained through Colombo canal (Ngwe Ta Chaung Canal) to Taung Tha Man pond. The wastewater of industrial area is drained to Dotehtawaddy River by an exclusive canal. 2-35

4 The Study on Water Supply Systems in Mandalay City and in the Central Dry Zone Part II Study for Mandalay City The drainage canal networks in the Mandalay City are shown in Fig The water quality of Shwe Te Chaung canal is 15 mg/liter as BOD and 18 mg/l as COD, in first sampling, 20 mg/l in second time. The Shwe Te Chaung canal is significantly polluted. The exclusive canal for industrial area is heavily polluted 900 mg COD/liter in first sampling, 500 mg COD/ liter in second sampling. This pollutant load is discharged into the Dotehtawaddy River. 2) Outline of Work (B) (i) Sampling Time: Once a month from July 2001 to June 2002 (ii) Sampling points Sampling points are 15 in number and consist of 2 tube wells of MCDC and 13 private wells. Their locations are shown in Fig (iii) Result Result of water quality tests regarding to Work (B) is shown in Table 2 of Supporting 2-A Result of Water Quality Test. Most wells meet with WQS-MCDC but few private wells have high concentration of iron throughout the year. 3) Outline of Work (C) (i) Sampling Time: Water sampling was conducted on 9 th October (ii) Sampling points: Sampling points is test well (JICA-NO.1). This well is located in same compound of No. 9 KOICA well. (iii) Result Result of water quality tests regarding to Work (C) is shown in table 3. of Supporting 2-A Result of Water Quality Test. Most items except iron meet with WQS-MCDC. 4) Outline of Work (D) (i) Sampling Time Water sampling was conducted on two occasions; in November 2001 and March Although simultaneous sampling for all the sampling points in each occasion was desirable, this was not possible due to the limited capacity of the laboratories. Therefore sampling of the total 100 wells was spilt into 3 sets; 35 wells, 35wells, and 30wells. (ii) Sampling points Sampling points are counted as 100 including 15 wells of Work (B). The sampling points are shown in Fig (iii) Result Result of water quality tests regarding to Work (D) is shown in Table 4 of Vol. III 2-36

5 The Study on Water Supply Systems in Mandalay City and in the Central Dry Zone Part II Study for Mandalay City Supporting 2-A Result of Water Quality Test. Most items except iron meet with WQS-MCDC. (4) Consideration Overall findings from results of the survey and data collection are listed below. -The water quality of production wells in the Mandalay City satisfies the Water Quality Standards for drinking water in the Mandalay City. -The water quality of the Ayeyarwaddy River and the Dotehtawaddy River is satisfactory for raw water for water supply. The following processes are required in the treatment facilities for water supply. Removal process for particulate matter Disinfection process - The wastewater of Shwe Te Chaung canal discharges into the Ayeyarwaddy River. Therefore, the candidate sites for intake point should be selected in upper stream from the discharge point of the wastewater of Shwe Te Chaung canal. -Industrial wastewater discharges into the Dotehtawaddy River. The candidate site of intake point should be selected in upper stream from the discharge point of the industrial wastewater. 2-37

6 <Groundwater> Table Groundwater and Surface Water Quality (Mandalay City) Sampling Point Sampling Date ph Color Turbidity (F.T.U) Conductibity (maicro mho/cm) Calcium Total Hardness Magnesium Chloride Total Alkalinity Iron Manganese Sulfate (SO42-) T.W-1 07-Mar ND T.W-2 27-Apr ND T.W-3 18-May ND T.W-4 13-Jun ND T.W-5 07-Oct ND T.W-6 05-Mar ND T.W-7 25-May ND T.W-8 21-Jun ND T.W-9 20-Apr ND T.W Oct ND T.W11 06-Feb ND T.W Jun ND T.W Mar ND T.W Apr > T.W Jun ND T.W Oct ND T.W Jun ND T.W Apr ND T.W Oct ND T.W Mar ND T.W May ND T.W Feb ND T.W May ND T.W Jun T.W Jun T.W Jun ND T.W Jun Industrial Zone(2) 13-Jun Tubewell MCDC-2 18-Jul >300 Tubewell MCDC Jul >300 Tubewell MCDC-6 15-Jul >300 KOICA Jul >300 KOICA Jul >300 KOICA-9 18-Jul >300 Test well 15-Aug > >300 <Surface water> Irrawaddy 22nd St. 18-Jul > > Irrawaddy Shangalay Kyuw 18-Jul > > : The value exceeds the water quality standard in the Mandalay City. 2-38

7 Table 2.2.4(1/2) Results of Water Quality Analysis (1) Sampling : 4 June 2001 items Unit Temperature o C Site ph Measur. Salinity % Electric Conductivity micro-mho/cm ,240 2,400 Total Solids (Total Residue) mg/l ,072 Chloride mg/l Calcium mg/l Magnesium mg/l Sulfate mg/l Analysis Total Hardness mg/l by CRO Permanent Hardness mg/l Total Alkalinity mg/l ND Nitrate Nitrogen (NO 3 -N) mg/l ph Total coliforms MPN Escherichia Coli. MPN Manganese mg/l ND ND ND ND 1.2 Dissolved Solids mg/l ,860 Zinc mg/l ND ND ND ND ND Arsenic mg/l ND ND ND ND - Copper mg/l ND ND ND ND ND Carbon Dioxide mg/l 4 4 ND ND 1500 Lead mg/l ND ND ND ND ND BOD mg/l 5* 5* 5* 15 *1) 3200 COD mg/l Dissolved Oxygen mg/l ND Color unit Sediment mg/l Turbidity F.T.U Cyanide mg/l ND ND ND ND ND Ammoniacal nitrogen (NH 4 -N) mg/l ND ND ND ND 0.04 Appearance - Slightly turbid Slightly turbid Slightly turbid Slightly turbid Turbid Color - yellowish brown yellowish brown yellowish brown gray yellowish brown Odor - Nil Nil Nil objectionable objectionable Analysis Chloride mg/l by WRUD Calcium mg/l Magnesium mg/l Sulfate mg/l Total Hardness mg/l Total Alkalinity mg/l ph Iron mg/l Sodium mg/l Potassium mg/l Hydrogen Carbonate ( HCO 3 - ) mg/l Carbonate ( CO 3 2- ) mg/l ND ND ND ND ND 1 Ayeyarwaddy River Intake point (No.1) 6 Production Tube Well (No.3) 2 Ayeyarwaddy River Intake point (No.2) 7 Production Tube Well (No.8) 3 Dotehtawaddy River Intake point (No.3) 8 Production Tube Well (No.12) 4 Shwe Te Chaung Canal 9 Production Tube Well (No.23) 5 Drainage Canal which discharges into Dotehtawaddy River 10 Production Tube Well (No.27) BOD: 5* means less than 5 mg/l. Water flow of Shwe Te Chaung Canal was approximately 1.4 m 3 /sec. when water sample was taken. ( canal width: 5 m, dipth: 0.6 m, velocity: 0.46 m/sec) Flow velocity of the drainage canal (No.5) could not measured. *1) :Doubtful Result 2-39

8 Table (1/2) Results of Water Quality Analysis (2) Sampling : 4 June 2001 items Unit Temperature o C Site ph Measur. Salinity % Electric Conductivity micro-mho/cm Total Solids (Total Residue) mg/l Chloride mg/l Calcium mg/l Magnesium mg/l Sulfate mg/l 14.4 ND ND Analysis Total Hardness mg/l by CRO Permanent Hardness mg/l ND Total Alkalinity mg/l Nitrate Nitrogen (NO 3 -N) mg/l ND ND ph Total coliforms MPN Escherichia Coli. MPN ND ND ND ND ND Manganese mg/l ND ND ND ND ND Dissolved Solids mg/l Zinc mg/l ND ND ND ND ND Arsenic mg/l 0.01 ND 0.01 ND ND Copper mg/l ND ND ND ND ND Carbon Dioxide mg/l ND ND ND ND ND Lead mg/l ND ND ND ND ND BOD mg/l 5* 5* 5* 5* 5* COD mg/l 2 ND 2 ND 2 Dissolved Oxygen mg/l Color unit ND ND ND ND ND Sediment mg/l ND ND ND ND ND Turbidity F.T.U. ND ND ND ND ND Cyanide mg/l ND ND ND ND ND Ammoniacal nitrogen (NH 4 -N) mg/l ND ND ND ND ND Appearance - clear clear clear clear clear Color - non non non non non Odor - Nil Nil Nil Nil Nil Analysis Chloride mg/l by WRUD Calcium mg/l Magnesium mg/l Sulfate mg/l Total Hardness mg/l Total Alkalinity mg/l ph Iron mg/l Sodium mg/l Potassium mg/l Hydrogen Carbonate ( HCO 3 - ) mg/l Carbonate ( CO 3 2- ) mg/l ND ND ND ND ND 1 Ayeyarwaddy River Intake point (No.1) 6 Production Tube Well (No.3) 2 Ayeyarwaddy River Intake point (No.2) 7 Production Tube Well (No.8) 3 Dotehtawaddy River Intake point (No.3) 8 Production Tube Well (No.12) 4 Shwe Te Chaung Canal 9 Production Tube Well (No.23) 5 Drainage Canal which discharges into Dotehtawaddy River 10 Production Tube Well (No.27) BOD: 5* means less than 5 mg/l. 2-40

9 Table 2.2.4(2/2) Water Quality of Surface Water items Unit Temperature o C Site ph Measur. Salinity % Electric Conductivity micro-mho/cm ,900 Total Solids (Total Residue) mg/l , ,279 Chloride mg/l Calcium mg/l Magnesium mg/l Sulfate mg/l Analysis Total Hardness mg/l by CRO Permanent Hardness mg/l Total Alkalinity mg/l ND Nitrate Nitrogen (NO 3 -N) mg/l ph Total coliforms MPN Fecal coliforms MPN ND + + ND + Manganese mg/l ND ND ND ND 0.40 Dissolved Solids mg/l ,696 Zinc mg/l ND Arsenic mg/l ND ND 0.01 ND ND Copper mg/l ND ND ND ND 0.06 Carbon Dioxide mg/l ND Lead Content mg/l ND ND ND ND BOD mg/l ND ND COD mg/l ND 4 ND Dissolved Oxygen mg/l ND Sediment mg/l Turbidity mg/l Cyanide mg/l Ammoniacal nitrogen (NH 4 -N) mg/l ND ND ND ND 5.00 Appearance - clear clear clear Slightly turbid Turbid Color - yellowish brown yellowish brown yellowish brown Back yellowish brown Odor - Nil Nil Nil objectionable objectionable Analysis Calcium mg/l by WRUD Magnesium mg/l Sulfate mg/l Total Hardness mg/l ,232 Total Alkalinity mg/l ph Total Iron mg/l Sodium mg/l Potassium mg/l Hydrogen Carbonate ( HCO 3 - ) mg/l Carbonate ( CO 3 2- ) mg/l ND ND ND ND ND 1 Ayeyarwaddy River Intake point (No.1) 2 Ayeyarwaddy River Intake point (No.2) 3 Dotehtawaddy River Intake point (No.3) 4 Shwe Te Chaung Canal 5 Drainage Canal which discharges into Dotehtawaddy River Water flow of Shwe Te Chaung Canal was approximately 0.4 m 3 /sec. when water sample was taken. ( canal width: 5 m, dipth: 0.6 m, velocity: 0.14 m/sec) Flow velocity of the drainage canal (No.5) could not measured. 2-41

10 Fig Schedule of Water Quality Survey in the Mandalay City and in the Central Dry Zone 1 well Year Work Month Jun. Jul. Aug. Sep. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May Jun. Jul Aug Sep Oct (A) The water quality survey of groundwater and surface water (10 points and 5 points) groundwater (5) + surface w. (5) surface water (5) (B) Water quality survey of continuous measurement for 15 wells 15 wells (C) Water quality analysis for a test well (D) Water quality survey of simultaneous measurement for 100 wells (15 wells + 85 wells) Total 100 wells Total 100 wells

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