HYDERABAD: DUE to ever-increasing population, sewage generation has increased manifold in Greater Hyderabad limits. To deal with this additional sewage flows, especially from Kukatpally, Picket and Balkapur nalas into Hussainsagar, the State government has decided to double the capacity of three Sewerage Treatment Plants (STPs) to further reduce pollution in the lake.
As increase in lake pollution is being attributed to industrial units releasing large amounts of sewage and effluents into the lake, the Hyderabad Metropolitan Development Authority (HMDA) is all set to take up the augmentation and upgradation of existing 5 mld, 20 mld and 30 mld capacity STPs into 10 mld, 40 mld and 60 mld capacity respectively with tertiary treatment, including Operation and Maintenance (O&M) around the lake for 20 years as well as creating associated infrastructure for the purpose.
The three existing STPs were constructed under the Hussainsagar Lake Project (HSLP) with loan provided by Japan International Cooperation Agency and were commissioned during 2012-14. These STPs were designed to treat the sewage for improving the water quality of the lake.
Treated water to be diverted to Musi
Sources told TNIE that augmentation and upgradation of three existing three STPs will be taken up under Hybrid Annuity Model (HAM) on design, finance, build, own, operate and transfer (DFBOOT) basis. The treated water would be utilised for non-domestic purposes or would be diverted to Musi river through interception and diversions (I&D) lines.
The 20 mld STP near the Khairatabad flyover, opposite IMAX theatres will be upgraded to 40 mld. Earlier, it was upgraded from secondary level to tertiary level on extended aeration process. This STP receives sewage from interception and diversion (I&D) works carried out on Balkapur nala and also from a man-hole on duplicate “A main” that runs through the STP premises.
During the upgrade, this STP was retrofitted to achieve biological nutrient removal and a tertiary membrane filtration was installed to polish the secondary effluent achieve very low Biological Oxygen Demand (BOD), Total Suspended Solids (TSS) and Total Phosphorus (TP) for direct discharge into the lake. The treated water from this STP is also being supplied to various parks around Hussainsagar for horticulture purposes.
The 30 mld STP is located near the Patigadda area opposite to KIMS, Secunderabad. This is a greenfield STP constructed under the HSLP, and receives sewage from interception and diversion (I&D) works on Picket Nala. The treatment process at this STP is the modified Johannesburg (JHB) process, and the secondary effluent is filtered through sand filters for polishing to be discharged into Picket nala while flowing into Hussainsagar.
Similarly, the five mld STP constructed under the HSLP is upstream in Kukatpally area, which is part of Hussainsagar Lake’s catchment area. This STP employs an oxidation ditch process with lamella plate settlers as secondary clarifiers and discharges secondary effluent into the IDL Cheruvu.