It is not the Omni processor technology, the process followed at PNP is as defined below:
- Step 1: The septage is received in the septage receiving station (SRS) via screen. The grit settles in the SRS, and the septage flows into the storage tank.
- Step 2: The septage homogenises in the collection tank. The three-day retention time in the collection tank is designed to address the incoming fresh septage from community toilets and public toilets too.
- Step 3: Submersible sludge pumps are placed in the collection tank to pump the settled sludge from the collection tank to the sludge holding tank. Two pumps are placed in the first two sections of the holding tank, and one pump in the last two sections. About 65-70% of the sludge is pumped to the sludge holding tank. The rest of the supernatant overflows to the MBBR tank under gravity.
- Step 4: The sludge from the sludge holding tank is pumped to the dewatering unit.
The dewatering unit consists of:
o Polymer mixing system
o Polymer maturation tank
o Polymer dosing system
o Dewatering – volute press (2 nos.)
The system is designed to handle the varying solids % in the sludge, and hence two volute press are provided. This also acts as a back-up in case of any maintenance requirements.
- Step 5: The dewatered solids fall into the trailer placed on the ground and is taken away to the composting yard for further composting with the MSW organic fraction. The filtrate from the volute flows to the MBBR.
- Step 6: The overflow from holding tank, and filtrate from volute is treated in theMBBR, and post the tertiary treatment, stored for use in the plant area in the treated water tank.
- The overall turn-around time for septage is 4-5 days, from the day of receipt into the FSTP.