For any nation or civilisation, Sewage Treatment is an essential requirement. It ensures that the harmful elements generated through human activities do not further endanger the environment. Sewage treatment is the simple process of treating sewage so that harmful elements are removed, while the recyclable elements are extracted for further usage.
Also known as wastewater management, sewage treatment has many benefits. Apart from benefitting the environment, sewage treatment also gives us access to clean water that is extracted at the end. This activity is carried out by sewage treatment plants in India. Run mostly by municipal corporations (sometimes in partnership with private players) these STP plants are vital in managing sewage and wastewater.
However, the operation and maintenance of STPs in India leaves much to be desired. Most of these plants are badly designed and operated. The main reason is because these are badly planned, installed without a proper evaluation of the factors that should decide the design and operation of a plant.
Location: The location of the plant is a vital factor because it decides the kind and amount of waste generated. There are multiple factors that must be considered when checking the location of a new plant. To begin with, it must be situated away from residential area. The land use around the site should also be minimal. In other words, it should be situated at a somewhat isolated area. Wind conditions must also be studied to ensure that there are no odour problems.
Flooding: Although we need a receiving waterbody nearby, it is important to ensure that the area is not susceptible to flooding. This means that it cannot be constructed in flood plains as this can effect the plant structure and the equipment. If it is situated in a high rainfall area, all precautions must be taken to ensure that it is protected from flooding.
Future expansion: Since an STP cannot be installed at any given spot, it is necessary that we plan for any future expansion if required. The plant design must accommodate linear expansions so that the treatment units can be extended easily. This must be done so that the treatment flow can be maintained even if the plant undergoes expansion later on.
This includes easy building of pipes and ducts that can be added to the present network without any dismantling required. Within the building, there should be enough space so that equipment can be modified and larger machinery can be installed. In fact, where the methodology permits it, the initial capacity of the plant should be far more than the actual requirement so that there is space to accommodate for expansion within the unit.
Connectivity: Although situated at an isolated area, the plant must be well connected by roads and pipes. In addition, the roads must be wide enough to accommodate for constants traffic of sewage trucks and disposal vehicles.
Steady electricity: Breakdown of electricity is a common problem that Sewage Treatment Plants in India are faced with. To ensure a smooth operation and minimise damage, it is imperative that we ensure a smooth supply of electricity. There should be a transformer on site and 24 X 7 backup. Any hitch in power supply must be addressed quickly and effectively.
Effluent quality: There are different types of STPs and the selection depends on the type of effluent we are dealing with. Some models are better at dealing with certain types of wastes than other models. Effluent quality will also decide whether the waste needs pre-treatment or secondary treatment. Hence, a thorough testing of the effluent quality at the site is essential. The strictest standards must be applied when deciding on which STP will suit the effluent.
Determining capacity: Apart from quality, quantity is also a critical aspect when selecting and STP. Quantity is a determining factor in a plant’s efficiency. Each methodology has its own specification when it comes to maximum and minimum allowed capacity. Hence, it is important to evaluate the daily flow into the plant. This should include a detailed assessment of dry weather flow, wet weather flow, peak hour flow as well as daily minimum flow.
Conclusion
The main reason behind the malfunctioning or under-utilisation of sewage treatment plants in India is the bad planning behind its installation. To avoid this, we must pay attention to all the factors that effect its operation and efficiency.
