- Greenish Raw Water at Kanhan River’ due to high
- Alage growth is the reason of hazy water at your tap
- NEERI Scientists to check water samples on Aug 17
Nagpur: Residents of North, East and parts of South Nagpur, need not have to worry about the hazy water supply coming from their taps these days. The reason for slight haziness appearance in water is due to organics in colloidal form in the raw water at Kanhan River. At the Tap end the water appears slightly hazy, but it is perfectly potable and safe for drinking purpose.
It may be mentioned here with literally ‘No Rains’ since last many days, the Raw water quality of Kanhan River suddenly changed & become almost greenish which is sign of too much dissolved algae or organics in water (Plz refer Kanhan River Picture above: Greenish raw water at Kanhan River).
Water Technology experts from NEERI has also opined that there is very fine colloidal of organic in raw water and has suggested methods for treatment which NMC-OCW has already started implementing.
It may be mentioned here, The Kanhan river water passes through forest and vegetation areas. During monsoon the river catchment area brings along vegetative growth through run-off in the river and during strong sunlight gets converted into very fine colloidal of organics.
These cannot be treated at water treatment facilities.
Inlet turbidity of Kanhan river raw water is in the range of 25-30 NTU and Water treatment plant outlet turbidity is 1.0 NTU. The pre-chlorination in kanhan raw water increased due to high algae which is increased from 0.5mg/lit to 1.7mg/lit.
However, to tackle the situation OCW has already initiated following actions to ensure good quality water reaches every household of citizens of Nagpur:
1.The optimum dozing of Pre and post chlorination is being maintained to ensure that water remains disinfected at Tap end.
2.Bleaching powder solution is being added at cascade aerator, Multiflow channel and common filter outlet.
3.Optimum dosing of PAC (Polyaluminium Chloride) is maintained as colloidal are hardly forming flocks and are not settling in the multiflow units.
4.Frequent backwashing of rapid filter beds is being carried out and backwash water is completely recycled to increase inlet turbidity. With increased turbidity the flocks’ forms and will settle down fast.
5.All Kanhan Feeder main ESR’s from North, East and parts of South Nagpur booster chlorine dosing is being done by either Sodium Hypochlorite solution formed by ECU or solution of Bleaching powder.
OCW approached the Scientists of water technology Dept., of NEERI Nagpur for their advice on the unprecedented condition of change raw water quality parameters. They have opined that the treatment water parameters are within desired limits.
On Thursday, August 17, the Scientists of water technology Dept., of NEERI Nagpur will carry out sampling and testing of the water samples from the Kanhan water source to the faucet. They will further analyse and advice on the changed raw water quality conditions and water potability.
Later NEERI Scientists have assured that they shall do periodic monitoring and surveillance of water quality of Nagpur 24X7 project.