GUWAHATI, June 27 - Though described as a bizarre development by the experts, yet it is alarming. A study has found very high levels of untreated or less treated arsenic and lead in the drinking water supplied by the six water treatment plants (WTPs) of Guwahati city, which poses a serious threat to public health.
According to the findings, the Panbazar WTP of the Public Health Engineering (PHE) Department, which is seemingly the most efficient among these WTPs in reducing the lead content of the water it treats, also fails in reducing the lead content below the maximum permissible limit. On the other hand, the other WTPs of the city are found to be reducing the lead content of their treated water to some extent.
Meanwhile, the PHE Retired Engineers� Forum has urged the State Government and the State Pollution Control Board to look into the matter to ensure safety of the people.
The study (Comparison of Treatment Efficiencies of the Water Treatment Plants of Guwahati City of Assam, India) conducted by Assam Engineering College (AEC) ME student Priyanka Kotoky and AEC Associate Professor Bibhash Sarma, had 12 water samples collected from the six WTPs. The WTPs included the Panbazar water treatment plant (of the Guwahati Municipal Corporation), Satpukhuri water treatment plant (GMC), Kamakhya water treatment plant (GMC), Panbazar water treatment plant (Public Health Engineering Department), Jalukbari water treatment plant (PHED) and the Zoo Road water treatment plant (Assam Urban Water Supply and Sewerage Board).
The samples collected from these WTPs were analysed for fluoride, iron, manganese, nitrate, hydrogen-ion concentration, turbidity, total dissolved solids, alkalinity, chloride, total hardness, sulphate, arsenic, lead, residual chlorine and bacteriological parameter.
The untreated and treated wastewater-laden river Brahmaputra water samples of the selected WTPs were done by field visit and collection. The water quality tests for the selected parameters were performed at the District Level Laboratory (DLL) of the Public Health Engineering Department (PHED) of Kamrup district, said Kotoky and Sarma.
Only the Panbazar WTP and the Kamakhya WTP of the GMC have been found successful in removing the bacteriological contamination of the water they are treating. However, all the WTPs being discussed are found to be successful in reducing turbidity to well below the maximum permissible limit of 5 (five) Nephelometric Turbidity Unit (NTU).
All the WTPs could reduce the total dissolved solids (TDS) values below the Bureau of Indian Standard (BIS) values, while the Panbazar WTP of the PHED is found to be the most efficient in reducing both TDS and alkalinity, said the two research scholars.
But they have found that there is no significant improvement in the treatment of chloride content of the treated water by any of these WTPs. Again, sulphate contents are found to be increased in almost all the treated water samples of these WTPs, even as all of them could reduce the amount of nitrate contents of the treated water. In this respect, the most efficient being the Panbazar WTP of the PHED.
All the WTPs are found to be efficient in reducing fluoride content of the water they are supplying to their consumers, said the research scholars.