Slow sand filter for water treatment

Name of Product/ Process
Slow Sand Filter For Water Treatment

Application / Use
For purifying polluted surface water for rural and small community water supplies

Salient features of technology / process
Slow sand filtration is an appropriate method of purifying polluted surface waters, especially for rural and small community water supplies in developing countries. Low turbidity (20 NTU) raw water is easy to treat in one step. Higher turbidities may need some pre-treatment. The method has several advantages: (i) It improves simultaneously the physical, chemical and bacteriological quality of raw water, and (ii) it is simple to construct, easy to operate and maintain at relatively low costs and manageable with local resources and skills.

Raw materials
The quality of product is highly acceptable in terms of turbidity (less than on eNTU) and free from micro-organisms. The dis-infection of treated water is, however, to be practised as a precautionary measure to take care of subsequent contaminations. It is a breakthrough for safe water supply in the villages where sustainable surface waters e.g. canal water systems, lakes, ponds are available.

Machinery / Equipment
Pumps

Status of technology (not commercialized/ commercialised / in production
Commercialised. Working at four full scale village level installations (Maharashtra, Tamil Nadu, Andhra Pradesh and Haryana)

Minimum economic unit and total investment
Rational cost comparison between slow and rapid sand filters has shown that slow sand filters are less expensive to build, operate and maintain than rapid filters upto the capacity of 7-9 mld. The filtration rate is 0.1 m3/hr/m2 sand depth. Approximate cost of 5 mld plant is Rs.23-30 lakh. The cost variation is influenced by design and location parameters

Technology transfer methodology

NEERI will provide broad technical details
Entrepreneur will study the infrastructure vis-à-vis his needs and capabilities and communicate his willingness for commercialisation of technology.
Full details with necessary technical back up will be provided

Technology demonstration cum training facilities
This can be arranged at places where plant may be working. The entreprenur can also make his own arrangement in collaboration with NEERI for construction of a study-cum-demonstration-cum-prototype plant

Product acceptability
Product is highly acceptable to rural community. It does not need continuous electricity supply. The water quality from slow sand filter is highly favoured by the customers

Marketability
Plant is meant for community water supply and all the agencies responsible for community water supply or any agency which wants to promote community water supply are the users of this technology. Demonstration plant in a region will attract other communities to have similar plants in their willages.

Is this technology location-specific? If so, please elaborate
Rural area for community water supply

Any gender-bias in technology utilisation?
No

Is any video-cassette available on the technology?
No

Any other relevant information not covered above
Nil

Terms and Conditions for technology transfer
The entrepreneur is free to start his own enterprise without NEERI’s support. However, if any advice or assistance is needed, NEERI will provide against fee

Name and address of technology generating institute / individual
Director
National Environmental Engineering Research Institute
Nehru Marg, Nagpur 440020
Maharashtra