selaulim water gets clean chit on manganese
The board conducted analyses from April to July, following complains. The analyses were carried out at the board's laboratory in Panaji and at the Margao-based Italab (Goa) Pvt Ltd, approved by the ministry of environment and forests.
On Tuesday, GSPCB chairman Jose Manual Noronha told TOI that the manganese levels found were within WHO-specified limits for drinking water.
While the content in April was 0.10 mg/litre, it was 0.05 mg/litre in May, 0.07 mg/litre in June and 0.04 mg/litre in July. The background document for development of WHO guidelines for drinking-water quality notes that concentrations below 0.05 mg/litre are usually acceptable to consumers, although this may vary with local circumstances.
GSPCB, meanwhile, has recommended that the government conduct, through an expert agency, a mapping study of the entire reservoir to establish the distribution of manganese. This would be through horizontal and vertical profiling along the surface and depth by dividing the reservoir into grids.
The board also recommended the installation of an on line water monitoring system to keep a check on manganese and iron contents in both raw and treated water supplied. It advised that the PWD be asked to install a treatment facility to treat the backwash water to meet the standard requirement prior to discharge and that the division concerned be asked to apply for necessary consent for the facility.
Finally, it recommended that the existing treatment system be upgraded taking into consideration existing manganese levels as the same are easily lowered using common treatment methods. Oxidation and filtration are usually adequate to achieve a manganese concentration of 0.05 mg/litre in drinking water, GSPCB's report noted.
Source - TOI - http://timesofindia.indiatimes.com/city/goa/Selaulim-water-gets-clean-chit-on-manganese/articleshow/22110565.cms