Dirtied by flood, Godavari water to be purified more

HYDERABAD: With increased turbidity in waters coming from the Godavari, the Hyderabad Metropolitan Water Supply and Sewerage Board (HMWS&SB) is taking measures to ensure quality with additional chemical treatment to the water. Turbidity crossed 200 NTU (nephelometric turbidity unit) and in places like Ramagundam it is close to 800 NTU, more than 20 times the normal (8-10 NTU).

Officials informed that water from the Krishna river is within the NTU limits which is around 5-6 NTU. However, citing heavy inflow, authorities claimed that they were geared up to treat the Krishna river water too as 70 per cent residents depend on it.

The board has stockpiled poly aluminium chloride (PAC). “We already have stocks up to 25 tonnes and 50 tonnes of additional PAC has been ordered to ensure that the situation is handled smoothly during the entire monsoon season as rains are expected till September. Each week five to eight tonnes of PAC are being used,” informed a senior official.  

The PAC is an important part of treatment when there are heavy rains and is used apart from ferric alum, which is used during normal days. Silt content is almost 100 per cent and was never witnessed in Godavari’s flooding for almost a hundred years.

“Generally there is between 1-2 NTU of turbidity, but we are able to maintain between 3-4 NTU. Humans can consume between 5-10 NTU and the raw water has 15 NTU. Right now the Godavari is flowing with 85-90 NTU, while Krishna river has 5-6 NTU. Last week, it was more than 200 NTU and in Ramagundam it was over 800. It is because of various factors like the presence of soil in its catchment area and the presence of farm lands,” explained the official.  

Within Outer Ring Road (ORR) limits, about 30 per cent of potable water being supplied is from the Godavari covering mostly the northern and western part of the city. While the Krishna’s 3-phases contribute to 275 MGD, the Godavari waters are between 160-170 MGD and 105 MGD from Singur. “Due to increased turbidity, the government has already stopped supplying water through Mission Bhagiratha and only Hyderabad is receiving it. After clearing of impurities, the process of chlorination at local level makes all the difference and makes the water potable,” added the official.