Design of STP/ETP for office campus in Thane, Mumbai, Maharashtra : Need advice

We have an office campus (Bayer india) in Thane , near Mumbai. The effluent referred here is mainly Office/Domestic wastes and Food wastes(90% food wastes from office canteen). Daily sewage volume=150KL/day approx.

The said Effluent goes into a settling tank and after that it is fed to the existing central STP/ETP. Existing STP/ETP is catering both the industrial as well as Domestic sewage.  But existing STP/ETP will be shut down soon and a new STP/ETP is to be planned near  the existing settling tank to treat this 150 KL  domestic sewage. There will not be any industrial sewage.

We also want to  use the processed water from the Sewage Treatment Plant for gardens and flushing toilets etc.

Can anyone guide us to select the suitable STP for our office campus.

Debajit Baruah