How does India’s second busiest airport – Mumbai’s Chhatrapati Shivaji Maharaj International Airport (CSMIA) – manage to recycle 100% of its wastewater? A CSMIA spokesperson takes us behind the scenes to understand what it takes to adhere to a zero-water discharge policy.
What are the various sustainability targets Mumbai airport has set for itself, across the board? What are the water consumption and reuse targets you have set?
Over the years, CSMIA has undertaken several initiatives in alignment to the Sustainable Development Goals (SDGs). The airport has systematically managed activities and operations to reduce water consumption and wastage across both the terminals. Utilisation of green power, increase in on-site renewable power generation, replacement of conventional fuel vehicles with EVs, adoption of new technologies, upgrading infrastructure to achieve energy saving and conservation, reduction in potable water consumption, increase in waste recycling and reuse to minimise disposal are some of the many initiatives which have been operational.
CSMIA’s initiatives towards saving water has been recognized by the Airport Carbon Accredited ACI’s (Airports Council International) program of Green Airport Recognition in 2020 under the project of water management.
CSMIA is also relentlessly working towards Achieving Net Zero Emission target by 2029.
In terms of volume, what are your freshwater requirements? How is this divided for various uses?
CSMIA systematically measures and monitors the quantity of water consumed on a day-to-day basis and identifies operations where water conservation techniques can be implemented, such as water efficiency projects (including water-efficient plumbing fixtures), waterless urinals etc.
Total freshwater usage at CSMIA is around 1.51 million cubic metres per year (FY 2019-20 pre-Covid consumption) out of which 1.2 million cubic metres is sourced from the Municipal Corporation of Greater Mumbai. In an endeavour to reduce the freshwater consumption, CSMIA recycles and reuses the wastewater generated and around 0.31 million cubic metres Sewage Treatement Plant-treated water is reused. CSMIA has also developed rainwater harvesting structures and used ~0.05 million cubic meter in the year FY 2019-20.
How much wastewater is generated across the facility per day? How does the quality of the wastewater differ, based on where it is generated? How is this monitored?
Under the zero-water discharge policy, CSMIA maintains 100% recycling of treated wastewater for cooling, landscaping, washing etc. A large quantity of water is consumed at the airport to support various operations at restrooms, food service, heating, ventilation, air conditioning, construction, landscaping and cleaning, to name a few. Thus, 2,000 cubic metres of sewage wastewater is generated each day. The input to these Sewage Treatment Plants (STP)s is measured by the metering system.
The quality parameters of the treated water are regularly monitored through NABET accredited laboratory and online analysers. Other initiatives have resulted in water consumption reduction of about 40% due to various conservation measures, such as rainwater harvesting, drip irrigation, wastewater treatment & recycling, and water efficiency projects, to name a few.
What is the installed capacity of the Sewage Treatment Plant?
Sewage Treatment Plants (STPs) helps in the treatment of the wastewater generated from various sources such as the terminal buildings, airside, landside and cargo facilities. The collective installed capacity of the treatment plant is 15 MLD.
What are the components of the installed STP?
Water usage at the airport results in generation of wastewater which contains contaminants such as suspended solids (SS), oil and grease (O&G) and residual chlorine amongst others, that can pollute the surrounding soil, surface water and groundwater. The contaminated water needs to be properly treated before being discharged from the sewage.
Thus, CSMIA in an effort to reuse wastewater, has installed Sewage Treatment Plants (STPs) to treat the wastewater generated at the airport premises from various sources. These STPs are based on the Sequential Batch Reactor (SBR) technology followed by Ultra Filtration (UF) and Reverse Osmosis (RO).
Is the water tested after purification? How?
Safety is of utmost priority to CSMIA and thus the airport monitors the quality parameters of the treated water through NABET accredited laboratory. The online metres and online analyzers are also used for water monitoring.
How and where is this purified water reused? How much of it is reused?
The treated water is partly utilised in toilets, gardening and as cooling make up water for the HVAC system in the terminal buildings.
What percentage of water requirements are met by the purified wastewater?
100 % treated water is being used, which accounts for 26% of total water requirements.
From a cost-benefit analysis point of view, how does investing in wastewater treatment help reduce the water utilities bill?
Treated water costs ₹60.48 per KL, whereas municipal water costs around ₹101 per KL.
What new technologies do you plan to incorporate in this program?
At present, all STPs have sufficient spare capacities and are based on the Facility Upgradation Plan. Additional STP requirement if any will be considered later during the expansion phase. We also plan to replace SBR technology with MBR (Membrane bioreactor) or MBBR (moving bed bioreactor), once operational life of this STP gets over. In addition to this, we have undertaken a study on the feasibility of activated carbon filters for optimum water utilisation while STP is operational.
Through continuous efforts and the use of innovative tools to increase efficiency, CSMIA diligently ensures no water bodies are affected due to the airport operations.