Wastewater management: A case study of Tiruchirapalli city in Tamil Nadu

Any form of liquid waste discharged by domestic residents, industries, agriculture and commercial establishments into water is called a wastewater. This water contains different quantities of contaminants which pollutes water and makes it unfit for any productive or domestic use. Set against the backdrop of dire need for effective and efficient management of wastewater, this paper is a case study of Tiruchirapalli city in Tamil Nadu. The analysis provided in the paper is an outcome of the field work carried out in the city, which emphasises for developing a strategy for the management of wastewater.

The authors of this paper first give a brief over view of the need for managing wastewater, which if left to accumulate might lead to production of malodorous gases and can cause diseases.

The paper then lists out the contaminants of wastewater, which are as follows:

  • Sediments
  • Suspended solids
  • Pathogens
  • Nutrients
  • Organic
  • Inorganic

Though the need for proper drainage and disposal system in India has been felt way back in 18 century , following which treatement plants have been set up , laws have been passed, the authors state that strategies for wastewater management have not been proposed so far in a comprehensive manner. For this they under took a study, which aims to prepare a strategy for wastewater management.

The objectives of the paper are as follows:

  • To review the status of wastewater quantity, quality, Collection, transport network, treatment, disposal, recycling and reuse.
  • To determine the level of awareness among people on the drainage schemes, network connections etc.
  • To identify the existing problems in quantitative manner.
  • To propose, alternative collection network, strategies for increasing sewer connections, optimal routing etc.

The authors undertook a field study in Tiruchirapalli, Tamil Nadu, to collect data, where field observation was made and interviews have been taken.

The paper then goes on to elaborate the field findings which are as follows:

  • Only 3 lagoons occupying 55.83 acres, were to be inadequate to handle the current sewage discharge.
  • Only 45% of houses have been assessed to be suitable to obtain sewer connections thus there is a need to expand the system to serve a population of 8.25 lakhs.
  • 32 areas in Tiruchirapalli city are omitted in the existing sewerage network

The paper then provides details of the field areas where the study has been carried out. After listing out the details of the state of wastewater system in the city, the problems were identified which are:

Lack of awareness among the public on the existing facility and procedures for obtaining sewer connections.

  • The duties of the private agency were not clearly specified leading to poor collection and transport.
  • As a result of which the sewage received at the treatment plant contain bulk quantities of floating materials and coarse solids. This creates a problem of clogging during transport, an increase in pollution load on the treatment units thereby decreasing the efficiency of aerobic pond and facultative stabilization pond.
  • The reasons for the above problems were found to be lack of administrative coordination among private agency, TWAD, and community.
  • It was also found that these agencies blame one another while failing in their duties.
  • The efficiency of the STP, Panchapur is very poor, only 40% BOD removal is obtained. This is mainly due to quality of the influent, silting of the lagoons, development of anaerobic conditions, lead to the reduction in the efficiency of the plant. The problem could be very well handled by making the agencies realize their responsibilities and try to build partnerships with the public.
  • Poor land use practices and discharge of sewage on to the river system has resulted in public demonstration and appeal calling for appropriate land use and potential reuse of wastewater for agriculture and pisciculture.
  • Reuse of wastewater for agriculture was not a successful one due to quality of treated wastewater, selection of crop and poor land use pattern.

The recommendations given by the authors are as follows:

  • A decentralized local sewerage system (individual sewerage system at each source with wastewater collection pits, cesspits or small sewage works, latrines, etc).
  • Safe collection and removal of sewage and rainwater in order to protect against disease.
  • Maintenance or improvement of the quality of surface water and groundwater.
  • Construction of permanently watertight sewers and repair of leaking sewers, pressure pipes and drains.
  • Optimization of drainage works.
  • Appropriate and adequate dimensioning of sewers and storage chambers to cope with peak flows (avoidance of flooding of properties, roads and land).
  • Suitable routing of sewers and arrangement of outfalls (in combined systems).
  • Flow control installations.
  • Use of materials, which fully meet the technical and hygiene standards.
  • Reuse of wastewater for agriculture and aquaculture i.e., Pisciculture.
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