The problem –
The use of UV disinfection is becoming popular as it avoids addition of Chloride in the effluent of the WWTP (Waste Water Treatment Plant).
An urban WWTP produced high quality effluent (after ternary treatment) but the color in the treated wastewater did not allow efficient disinfection by UV technology.
The presence of E-Coli in the water required chlorine addition or UV treatment.
The UV technology provider requested a UVT (Ultra-violet transmission) value above 60%, which was never reached in the WWTP.
The solution
After laboratory tests, it was decided to inject Sodium Aluminate in the biological reactor.
Color removal in urban wastewater by Sodium Aluminate addition
Results
Within a few days, the UVT level reached the required limit and has been kept at the same level for more than 3 years.
The UV technology allowed reduction of Coli bacteria by several orders of magnitude.
The addition of Sodium Aluminate is controlled by UVT measurements and analysis of the secondary sludge (RAS)
Similar results have been achieved recently in tests of other WWTPs.
level in treated wastewater
