Mumbai city is having the previlage of unpolluted water resources around its vicinity. Drinking water for Mumbai comes from various lakes/reservoirs such as Bhatsa, Upper Vaitarna, Middle Vaitarna, Modaksagar (Lower Vaitarna), Tansa. Total quantity of water coming from these lakes is approximately 4128 mld.
More than half of this water requirement i.e. around 2000 mld comes from Bhatsa dam located on Bhatsai River near Shahapur. Thus Bhatsa Dam is the biggest source of drinking water to Mumbai City. Bhatsa scheme consists of a weir at Pise (40 kms downstream Bhatsa Dam in river course) & various installations like Pumping Stations, Electrical Substations, Treatment Plants etc. in Pise & Panjrapur ( Located at 8 kms from Pise). Pise Panjrapur Complex ( Capacity 2000 mld) is one of the biggest treatment plants in Asia. It consists of various stages of treatment Plant Stage I,Stage II & III, Stage IIIA.
There is water loss of approximately 55 to 65 mld in the various treatment processes of these stages of treatment plants. This waste water generated from Filter Backwash & Clarifier Desludging is having very high turbidity & suspended solids. This water is discharged into a nearby seasonal natural stream which ultimately goes into Kalyan creek. This waste quantity of approximately 60 mld is huge enough for supplying water to a small town. Moreover looking at the increasing population of Mumbai city, MCGM planned to make Panjrapur Treatment Plant as zero discharge plant. Accordingly, the project of Water Reclamation Plant, Panjrapur was started by MCGM.
The various waste water resources discharged from Panjrapur Treatment Plant into a natural course are as follows
1) Filter Backwash Water Stream from Plant I,II,III – 35 mld 2) Clarifier Desludging Stream Plant I,II,III – 12 mld
3) Filter Backwash Water Stream from Plant IIIA – 9 mld 4) Clarifier Desludging Stream Plant IIIA – 4 mld
5) Detailed study of waste water of all these streams has been done & process was designed accordingly. Turbidity & suspended solids of these waste water streams were found as high as 1000 units. After detailed design & engineering, work of this plant was started. Till date, first three streams comprising of approximately 56 mld are commissioned & are in operations since August 2016. Fourth stream of Clarifier Desludging Stream Plant IIIA (4 mld) is nearing fast for completion. Thus total 60 mld (with an additional capacity of 6mld) water will be recirculated soon. This will make Panjrapur Treatment Plant a zero discharge plant fulfilling all pollution norms giving an additional 60 mld water to the city.
MCGM will also introduce Ozonisation first time through this plant. The parameters of recirculated water are also excellent & are within the permissible limits. A chart of various inlet/ outlet samples from the month of February 2017 is here for referrence
Name of inlet/outlet samples pH Turbidity in NTU Total Suspended Solids in mg/L
FBW Stream I,II,III inlet 7.1 576 412
FBW Stream I,II,III Outlet 7.2 0.90 1.0
FBW Stream IIIA inlet 7.2 450 362
FBW Stream IIIA Outlet 7.1 1.0 1.0
Raw Water from Pise to Panjrapur WTP 7.3 4.8 1.8
Clarifier Sludge Stream I,II,III inlet 7.2 843 630
Clarifier Sludge Stream I,II,III 7.0 0.88 1.0
Thus Water Reclamation Plant, Panjrapur is one of its own kind in many aspects.