Evaluation of operation and maintenance of sewage treatment plants in India - Control of urban pollution series - CPCB (2007)

This study was commissioned recognizing the fact that discharge of untreated sewage occurs not only because of inadequate installed capacity of sewage plants, but also due to the inadequate maintenance of existing plants.The study evaluated the performance of these plants and identified main problems, both technical and administrative. The methodology followed included:

• Individual plant visits
• Discussions with operation staff
• Evaluation of technological and management aspects

175  STPs located in metropolitan, Class I cities and Class II towns (96 nos) were identified for their performance evaluation by:

• Getting information on a prescribed format (Annexure I) from the State Govts./implementing/ O&M agencies, and
• Physical inspection through random checking at STP sites

Out of 175 identified STPs spread over 15 states, the present report has included only 84 STPs of 13 different technologies spread over 9 states of India  due to a lack of response from the other STPs.  Of these, the performance of 8 was good, 30 satisfactory, while the other 45 were performing poorly.

The study found that:

• Capacity utilization in general was inadequate
• Sludge handing appeared to be most neglected area in STPs operation
• Alternate power supply facility was not available in most of the cases
• Utilization of biogas generated from UASB reactors or sludge digesters was also not adequate in most of the cases
• There was no gas generation and utilization in 13 plants in spite of having anaerobic reactors/digesters
• Only in 12 STPs the gas generated was being utilized as domestic fuel (5 STPs) or as fuel for gas engine ( 4 STPs) or duel fuel generator, DFG (3 STPs)
• Alternate power supply facility was not available in most of the cases
• Fund shortage was an important factor in poor operation and maintenance of STPs and was reported in 26 cases
• Lack of proper laboratories at site was another area that needed attention
• In majority of the cases, operation of the STPs was looked after by contractors who deputed unqualified or less qualified staff at site, which was an important factor responsible for poor operation of STPs.

The report also includes a summary of the situation of each plant surveyed, and details of the measures to be taken to combat these inadequacies.

A copy of the report can be downloaded from below: