Sewage Treatment-UASB Technology Under Ganga Action Plan

The Ganga Action Plan (GAP) Phase-I consists, inter-alia, of commissioning of sewage treatment plants in the 25 Class-I towns along the bank of the Ganga as a major component for sewage pollution control and river water quality improvement.

In the planning stages of GAP-I in the '80s, conventional technologies for sewage treatment were adopted with designs on normative basis by the state implementing agencies due to lack of experience in this area.

These technologies comprised of Activated Sludge, Trickling Filter, Aerated Lagoon and Simple Oxidation Pond Systems.

Under GAP-I, an integrated sanitation project at Kanpur and Mirzapur in UP with about Rs 50 crores expenditure under the Indo-Dutch Economic Cooperation Programme was taken up in 1988. Under this programme, amongst other innovative concepts like community participation and health promotion, institutional strengthening, ETP for tannery wastes, chrome recovery from tannery waste etc., a cost-effective Dutch technology called Upflow Anaerobic Sludge Blanket (UASB) process has been experimented with, initially through a pilot plant of 5 mld capacity at Kanpur and its performance was evaluated in 1990. Based on such evaluation, a comprehensive sewage treatment process for Mirzapur, using UASB as the core process and with appropriate post treatment plan was adopted.

The 14 mld UASB sewage treatment plant with a polishing pond was commissioned in 1995 at Mirzapur. The plant is in satisfactory operation, leading to substantial savings in operation and maintenance costs.

The main advantage of the UASB process is the minimal land requirement, least equipment and energy dependence and generation of biogas power from the UASB reactor. The system is cheaper to operate and maintain with appropriate skilled monitoring. The treated sewage at Mirzapur for most of the time was up to the standards of 30 mg/litre of BOD and 50 mg/1itre of suspended solids. The effluent from the system is being used for irrigation.

Based on the operational experience in these years, engineering and design modi-fications have been evolved with Dutch inputs and this process is being replicated in about 15 towns under the Yamuna Action Plan in UP and Haryana and considered for adoption by other NRCP states.

Innovative Sewage Treatment Technology

For the first time in the country under Integrated Sanitation Project of Indo-dutch Collaboration Cooperation of Ganga Action Plan, Phase-I, and Innovative Sewage Treatment Technology called Upflow Anaerobic Sludge Blanket Process (UASB) was experimented with sewage of 5 mld capacity. After two years data evaluation, a post-treatment pond system has been integrated into the process for meeting the Ganga Action Plan treated sewage standards. This Dutch Technology required land, minimal rotating equipment and least operation and maintenance cost, apart from facilitating biogas- power generation to meet the full power needs of the treatment plant instead of energy dependency like conventional mechanised treatment plants. This technology has also been found to withstand shock loads, long duration of power cuts without losing its efficacy for the temperatures prevailing in most parts of the country. Having successful demonstration of commercial scale plants under GAP-I, all other NRCP States of the country are adopting this process based on techno-economic evaluation based on site conditions. The effluent is fit for use as an irrigant and put to use as such.