Case Study P & G


01. Bio-Augmentation of existing STPs and ETPs:

a. CLIENT: Procter & Gamble Limited, Chennai (Rialto Enterprises Pvt. Ltd.)

b. PLANT DETAILS: The plant is a modular unit made of FRP to treat sewage. It works on the RBC (Rotary Biological Contractors) principle. The collection sump is about 23 KLD in capacity as against a flow of 36 KLD. From the collection sump it is pumped in to the first chamber of the modular treatment plant by a 1 .5 HP feed pump and then flows in to the primary clarifier with parallel plates made of FRP. The clarified water flows to the RBC chamber, which has three rotary wheels, and a gearbox pump of 1.5 HP keeps the wheels in motion. The biologically treated water flows in to the secondary clarifier with FRP plates for settling of the biological sludge. The clarified water is fed in to the Pressure Sand Filter (PSF) and Activated Carbon Filter (ACF) for tertiary treatment and the treated water is used for gardening. The Biological sludge is dewatered dried and used as manure.

c. PROBLEMS BEING FACED: The efficiency of the plant is low as it is designed for 23 KLD and the flow is 36 KLD. As a result, the readings received before treatment were as follows as checked by them and given to us:

BDL :Below Detection Level, NR: Not recorded.

The wastewater recycled for gardening lead to plants turning yellow and dying in some cases. There was fairly high foul odour all around the plant. As there was no bar screen, solids in terms of paper and floating matter got into the system. Sludge floated in the secondary clarifier as a result of low retention time probably.  The RBC covered by lids on top. So the contact with air is less leading to reduced oxygen transfer to the RBC.

d. RESULTS AFTER TREATMENT:  The following readings were recorded by the client after the plant was treated by us:

The other benefits that accrued according to the client were as follows:

  1. The plants became rich green and quality of the soil improved.
  2. Their cost of running the plant got reduced by about 30% according to them.