International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 11 Issue: 08 | Aug 2024
p-ISSN: 2395-0072
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The Confluence of Sewage and Stormwater in Sewage District C of Mysuru City - a case study Veena N. Murthy1, B.M. Krishna2, Arun Kumar K.3 1P.G Student, JSS STU & University Campus, Karnataka, India
2 Associate professor, JSS STU & University Campus, Karnataka, India 3 Associate professor, Government Engineering College, K.R. Pete, Karnataka, India ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - The Karnataka State Pollution Control Board
rate supply of 135 litres, as per the Central Public Health and Environmental Engineering Organization (CPHEEO) norms.
(KSPCB) is the regulatory body responsible for enforcing environmental laws and regulations in Karnataka. Various studies have been conducted to assess the amount of raw sewage entering the natural nalla/ lakes in Mysuru city. One such study was carried out under the guidance of KSPCB to examine confluence locations of sewage with stormwater valleys (also known as Raja Kaluve) in Sewage District 'C' of Mysuru City. The objective of the study was to identify the main areas where sewage and stormwater drains converge, to measure the amount of sewage flowing into the major stormwater drains that lead to the Sewage Treatment Plant (STP) and to evaluate the quality of wastewater that enters the natural nalla. Major confluence locations of sewage and stormwater drains (Raja Kaluve) were identified. Records were created to document the confluence locations and quantify the mixed flow of untreated sewage and treated effluent that enters the natural nallas/lakes. The study revealed that a significant volume of raw sewage from District 'C' was entering the natural nalla, which would subsequently travel and reach Paschim Vahini, posing a threat to the ecosystem. BOD and Total coliform levels of the water samples at the confluence locations exceeded the limits prescribed by CPCB.
Mysuru has an underground drainage (UGD) system that covers about 70% of the city’s area. It comprises five major sewage Districts, A, B, C, D & E, within the Comprehensive Development Plan (CDP) boundary, and two Districts, G & F, outside the CDP boundary. The total length of the sewer line provided is about 1560 km, and the total installed capacity of Sewage Treatment Plants (STPs) in the city is about 172.5 MLD (3 nos. - 60 MLD, 67.5 MLD, 45 MLD). The total quantity of sewage collected is about 95 MLD, about 55% of the amount generated. In the case of Sewage District ‘C’, it is observed that only a small amount of sewage is reaching the STP due to various issues. These include obstructions during solid waste dumping in the stormwater drains carrying untreated sewage, non-operation of interception and diversion works, ongoing pipeline works and repairs of aerators in the STP. The Kesare STP, which is of aerated lagoon type, has a designed capacity of 45 MLD. However, it can only treat a fraction of the total sewage generated, which reaches the STP through the underground drainage system. The untreated sewage flows into the stormwater drains and eventually reaches the natural nalla.
Key Words: Confluence, Drains, Mysuru city, Raja Kaluve, Sewage.
2. LITERATURE REVIEW
1. INTRODUCTION
In Karnataka, two main types of sewage treatment plants are used to treat domestic sewage from small and medium towns. Waste stabilization ponds (WSP) and aerated lagoons were preferred for easy operation and maintenance. These technologies successfully treated sewage effluent with BOD (Biochemical Oxygen Demand) levels of 30 mg/l or lower. However, as the Central Pollution Control Board (CPCB) established stringent effluent parameters for treated effluent discharge to land or water bodies, with BOD levels of 10 mg/l or lower and COD (Chemical Oxygen Demand) levels of 50 mg/l or lower, some STPs have been upgraded.
Mysuru is a city located in the southern part of Karnataka. It is known for its palaces, rich culture, and peacefulness. The administrative seat of Mysuru District is one of the largest in Karnataka. It is 770 meters above mean sea level with geographical coordinates of 12.18° N 76.42° E. Currently, the city has a population of about 13,16,000 and a floating population of approximately 50,000 to 1,00,000 during Dasara Festival. The city gets its surface water sources from the Kaveri and Kabini rivers. Newly developed and extended areas under Mysuru Urban Development Authority (MUDA) limits are supplied with Borewell (BW) water. The total water supply to the city from surface sources is about 214 Million Liters per day (MLD) (4 WTPs at Melapura, Hongalli, Belagola, and Rammanahalli), which is more than the minimum per capita
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In recent years, technologies like Sequential Bioreactors (SBR), Membrane Bioreactors (MBR), Moving Bed Bioreactors (MBBR), and Soil Biotechnology (SBT) have been constructed to treat domestic sewage.
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