Location
The Plant is located on the eastern bank of river Ganga, about 3 km from Khardha railway station and at a distance of 32 km north of Sealdah station, near Rahara Ram Krishna Mission within the Bandipur Gram Panchyat area.
Background Information
The Low Cost Sewage Treatment Plant (WSP) was constructed in March, 1993 though the site selection and land acquisition works were initiated in 1989. The site for Low Cost STP was marshy land, containing predominantly water hyacinth and duckweed. Only one crop of paddy used to be produced in a year over a part of the land during summer time.
Theory of System
In this treatment plant, treatment of waste water is achieved by means of biological process in the series of ponds i.e. i) Anaerobic ii) Facultative and iii) Maturation in which anaerobic, aerobic and facultative bacteria and production of algae with the help of sunlight (photosynthesis) neutralise/ stabilise the waste water (i.e. reduction of BOD) to a considerable degree. The Facultative and Maturation ponds are used for pisciculture. The whole process of treatment is based on symbiotic relationship and require low energy, power, maintenance cost and acquire 85 to 95 per cent plant efficiency.
Process Description
Sewage/waste water comes to the screen chamber (main pump house) from an intercepted channel with the help of penstock gates. From the screen chamber, the sewage enters into the wet pit where sewage is pumped to the splitting chamber and distributed over two anaerobic ponds (detention time - 1day) and removal of BOD-5 (about 60 per cent). After the anaerobic pond, through inter- connections, the waste water is distributed over 3 Facultative ponds (detention time - 4 days) and removal of BOD-5 (about 70 per cent). Then, the waste water is sent to 2 Maturation Ponds in series, (detention time 3 days), where the final treatment is achieved. Pisciculture is done in both Facultative and Maturation ponds for the reduction of BOD-5. The treated waste water is used for land irrigation, excess of which is sent to the River Ganga through the existing channel.
Resource Recovery
1. Pisciculture
1.1 Revenue Earning
Pisciculture activity is being carried out in both Facultative and Maturation ponds through the local panchyat on lease basis since 1996. The period of lease is seven years. During the lease period, the said leasee will give to the Authority Rs 7.80 lakhs for the first five years. We have already received Rs 1.80 lakhs. The lease rent as per agreement is as follows :-
(To be settled for the last 2 years.)
l.2 Employment
About 12 fishermen and 10 guards per day are directly engaged for pisciculture at STP. Besides, 10 to 20 buyers regularly come and collect fish, weighing about 90 to 100 kg. Socio-economic upliftment of the landless villagers/ farmers, cultivators has been achieved due to the construction of STP.
1.3 Irrigation
Treated water is being supplied to the irrigation field for cultivation but significant revenue earning could not be made possible from the poor farmers. On the other hand, it helps to increase cultivation in surrounding areas as well as to increase social benefit.
1.4 Organic Manure
Digested sludge, which is deposited at the bottom of ponds, has manural value and so could be commercially utilised during the periodical desludging/desiltation of ponds. But it is not appicable under this STP at present, because the period of desludging has not yet been reached. We hope that a considerable revenue could be made possible to earn in the future by selling the digested sludge to the farmers.
Performance of the Plant
Performance of the STP is being monitored by the All India Institute Of Hygiene and Public Health. From the performance report it will be evident that the plant is fulfilling the requirement. Some specific analysis results are tabulated below:
Average
Influent BOD-5 - 140.63 mg/1
Effluent BOD-5 - 15.00 mg/1
Influent SS - 406.00 mg/1
Effluent SS - 39.75 mg/1
DO Level
Facultative Pond - 13.47 mg/1
Maturation Pond - 8.02 mg/1
Faecal Coliform per 100 ml.
Influent - 1.8 x 106
Effluent - 3.6 x 106
Operation and Maintenance Cost
The total cost for O&M is Rs. 3.41 lakhs. The O & M for energy charge of MPS is met from O&M cost of Titagarh STP (ASP type). The cost for STP itself is Rs 1.45 lakhs and that for MPS is Rs 1.96 lakhs.
Conclusion
A new concept i.e. Waste Stabil-isation Pond (WSP) or Low Cost Sewage Treatment Plant is now being adopted to treat waste water and performs well over the conventional sewage treatment plant. In a country like India, low cost technology is an ideal solution for sewage treatment, considering its simplicity and less O&M cost, easier maintenance with high efficiency and is, therefore, sustainable. Moreover, removal of pathogens (faecal coliforms) is of a higher order (107- 103)/100ml compared to that of conventional type of treatment (107- 105) /100ml.