Sri Sivasubramaniya Nadar College of Engineering
OP-3: Water Use

RAINWATER HARVESTING:

At SSN College, a comprehensive rainwater harvesting system has been implemented, featuring 418 percolation pits, 12 storage wells, and a rainwater trench system. The percolation pits are strategically located across the campus to capture runoff water and recharge the groundwater table, while the storage wells conserve rainwater for non-potable uses, reducing dependency on external sources. The rainwater trenches guide surface runoff to designated areas, preventing waterlogging and promoting efficient groundwater recharge. This initiative not only supports sustainable water management but also serves as a practical demonstration of environmental stewardship. As a result, the campus is more self-sufficient and resilient in water resource management, contributing to a sustainable future.

• Percolation Pit – 418 Nos (2207.83 cu.m)
• Rainwater storage Well – 12 Nos (7234.56 cu.m)
• Rainwater Trench (Approx. 39049.2 cu.m)

Reference Link for photographs 

1.Refer from page 3 to 25 for details(photographs and drawings of the rainwater harvesting systems)

https://www.ssn.edu.in/wp-content/uploads/2024/11/OP__3.pdf

2.SSN WWater conservation

https://www.ssn.edu.in/wp-content/uploads/2024/02/7.1.4_Water-conservation.pdf

SEWAGE TREATMENT PLANT:

The sewage from the building along with wastewater from toilets and kitchens etc., is treated in the sewage treatment plant. Sewage treatment plant design is as per CPCB & SPCB norms. The sewage treatment plant for the entire campus capacity is 500 KLD (Existing 100 KLD and New STP 400 KLD) designed to treat combined sewage (i.e., soil and wastewater). The treatment  have extended aeration with SBR technology. After the treatment, the water is used for landscape irrigation purposes.

The Sequencing Batch Reactor (SBR) is an activated sludge process designed to operate under sequences for the various phases of biological treatment where aeration and sludge settlement both occur in the same tank. SBR systems contain either two or more reactor tanks that are operated in parallel, or one equalization tank and one reactor tank. 

• Total Water required on campus: 487 KLD
• Total Wastewater generated on campus: 438 KLD
• Total capacity of the STP system on campus: 500 KLD

Reference Link for photographs 

1.Refer from page 25 to 96 for  Sewage treatment details(test reports, photographs and process)

https://www.ssn.edu.in/wp-content/uploads/2024/11/OP__3.pdf

2.SSN WWater conservation

https://www.ssn.edu.in/wp-content/uploads/2024/02/7.1.4_Water-conservation.pdf

GREEN INFRASTRUCTURE :

SSN campus implements green infrastructure to manage stormwater and enhance groundwater recharge. The campus uses the following methods to collect and return water to surface water or groundwater:

• The campus has installed rainwater harvesting structures across multiple locations. These systems capture rainwater from rooftops and other surfaces, directing it into recharge pits and underground storage tanks. The harvested water is then allowed to percolate into the soil, replenishing the groundwater table.
• Several percolation pits and recharge wells are strategically placed around the campus to facilitate groundwater recharge. These structures capture runoff water during heavy rains, allowing it to seep into the ground and replenish the aquifers.
• The campus incorporates Sustainable Drainage Systems such as pavements, which help slow down surface runoff, enhance infiltration, and filter pollutants before the water returns to the groundwater system.

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Methodologies

The SSN campus utilizes comprehensive green infrastructure strategies to manage, recover, and reuse water effectively. To evaluate the efficiency of these systems, detailed methodologies are used to estimate the annual volume of rainwater harvested, water recovered for reuse, and water returned to the environment through on-site green infrastructure.

1. Estimation of Rainwater Harvested On-Site for Storage and Use:

   • The estimated volume of rainwater harvested on-site is 48,491.59 KL (Kiloliters per Day). This estimation is done based on the storage capacity of pits and tanks and percolation rate of the soil. 
   • The catchment area includes rooftops and paved surfaces, while the annual rainfall depth is derived from historical weather data (past 5 years). A runoff coefficient, typically between 0.6 and 0.9, accounts for the efficiency of water collection based on the surface type. The calculated volume represents the potential rainwater collected and stored annually for various on-site uses.(Methodology followed as per Indian Green building Campus  rating )

2. Estimation of Water Recovered On-Site for Reuse:

   • The estimated volume of water recovered for reuse on the SSN campus is 395 KL. This figure includes treated wastewater from the on-site Sewage Treatment Plant (STP), which is redirected for non-potable applications like landscaping and irrigation.
   • The volume is monitored using digital flow meters installed at key points of the treated water distribution network. The data from these meters helps in estimating the daily and annual volumes of water reused, enhancing the efficiency of water recycling efforts.

3. Estimation of Water Collected and Returned Through On-Site Green Infrastructure:

   • The estimated volume of water collected and returned to the groundwater system through on-site green infrastructure is 395 KL. This includes contributions from percolation pits, recharge wells, and Storm water drains.
   • The infiltration rate is periodically assessed to reflect the soil's absorption capacity. Regular monitoring ensures accurate estimates, contributing to the sustainable management of the groundwater resources on campus.(The percolation/absorbtion rate is arrived through hydrogeological test reportconducted on-site).

2.SSN WWater conservation

https://www.ssn.edu.in/wp-content/uploads/2024/02/7.1.4_Water-conservation.pdf