Allahabad, India to Address Sewer Problems

To provide a comprehensive sewerage system in the city, an exhaustive plan has been prepared under the Jawaharlal Nehru National Urban Mission (JNNURM). The plan envisages construction of Sewage Treatment Plants (STPs) and laying of branch sewer lines in different parts of the city for having a total, comprehensive and holistic solution to the sewerage problem of the city, according to The Times of India.

Talking to TOI, project manager and engineer of Jal Nigam, DC Gupta said that in the first phase, a new STP would be constructed at Rajapur. It would have a capacity of 60 MLD. For this, land has already been identified in Mehadauri Kachar.

The proposed STP would be based on UASB+ Aerated lagoon followed by chlorination. It will receive sewage for treatment of major part of in sewerage district D through Mumfordganj pumping station and some portion of district C through Rajapur pumping station.

In addition, the branch sewer lines would also be laid in the northern parts of the city measuring upto 250 km. The branch lines would be laid in the areas of Rajapur, Mumfordganj, Katra, Mehdauri , Colonelganj, Ashok Nagar, Tagore Town, George Town and some parts of Civil Lines. Besides laying of new sewage pipes, the plan covers repair of the old sewage system so that a holistic solution can be provided to denizens.

In addition, there would be construction of Rajapur Interceptor Sewer. Investigation reveals that provision of interception and diversion of sewage flow of Rasoolabad drain along with 13 other drains is a necessity for which treatment facility is already proposed at Rajapur STP. Considering the holistic approach, interception and diversion of Rasoolabad drain along with 13 other drains discharging into the Rasoolabad area is necessary for which interceptor sewer with subsequent drain tapping arrangements and an MPS in the Rajapur STP premises is being proposed .

**Following provisions have been made for the successful completion of work.

(i)Considering the saturated soil conditions and perched water table, dewatering through well point equipments.

(ii) Closed timbering in the entire length as site is in flood plain of the river.

(iii) Reinforced cement concrete bedding and its anchoring with pipe for the structural safety of the proposed sewers .

(iv) RCC Circular manholes for the sewers to avoid infiltration.

(v) Drain tapping arrangement for interception of drains.

(vi) Under reamed pile foundation for structural safety of manholes.

**Existing sewerage system of city:

The existing sewerage system in city is a complicated one with network of sewers aided by pumping stations to carry the liquid waste up to sewage farms. The system includes about 475 km of major sewers and branches of various sizes, shapes and material. A large portion of the sewerage network is very old and has already completed its designed life. A number of old sewers are of brick masonry construction, some of which are egg shaped. Certain stretches of the system are under combined functions. Newer sewers are generally circular RCC. The pumping stations are also of various Configurations, some of which are very old and need major renovation.

**Current deficiencies:

(1) Poor maintenance: The majority of the branch sewerage system is at any time either completely blocked or its capacity is severely reduced by silt and solid waste. Sewer maintenance is restricted to emergency clearing of blockages and is given low priority.

(2) Silting and surcharging: Sections of the trunk sewers are heavily silted. Reduced capacity from silting results in sewage overflows from manholes to surface drains during peak flow periods. Problems may also be caused by structural damage in some sections.

(3) Ageing infrastructure: The existing trunk sewer system is over 75 years old and has been allowed to deteriorate to the point where rehabilitation or replacement is necessary. Many of the sewers have not been inspected.

(4) Storm water and solid waste ingress to sewers: Damaged manholes, sewer defects particularly around the drains and linking of drains to the sewerage system have led to increased risk of solid waste entering and blocking the system