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By 2026, over 600 Indian cities face acute water shortage every summer. Bengaluru trucks in 7,000–9,000 tankers daily. Gurugram societies pay ₹90–120 per 1,000 litres from private suppliers. Chennai’s IT corridor survives on desalinated water costing ₹140–₹180 per KL.
Yet, in the same cities, more than 70% of the water that enters as fresh supply leaves as sewage. And most of it is thrown away after minimal or no treatment, highlighting the urgent need to adopt advanced wastewater treatment solutions for modern cities.
The mathematics is brutal: every day India flushes away 60,000–65,000 million litres of potentially reusable water while spending thousands of crores extracting, pumping, and purifying fresh water that is then used for flushing toilets and washing cars. Cities that invest in energy-efficient wastewater systems drastically cut these losses and reduce reliance on tanker water overnight.
Treated sewage water reuse is no longer a “green” luxury; it is the fastest, cheapest, and most scalable way to cut freshwater dependency by 30–70% in residential, commercial, and industrial projects — one of the strongest arguments behind why every institution needs a wastewater treatment plant. Many developers and industries are now choosing modern STP plants in India not just for compliance but for long-term operational savings.
Add to this the increasing shift toward AI-powered smart STP operations. Which allow cities and large campuses to monitor quality, predict loads, and optimise energy consumption. For those planning new installations, the SKF Elixer Vulcan STP product range offers highly efficient AABR-based solutions designed for consistent, high-quality treated water that supports reuse at scale.
The Urban Freshwater Crisis in Numbers (2025)
- 21 major cities, including Delhi, Bengaluru, Chennai, and Hyderabad, are expected to run out of groundwater by 2030.
- Average per capita freshwater availability has fallen from 5,178 cubic metres in 1951 to roughly 1,400 cubic metres today.
- Municipal and industrial demand is growing at 6–8 % annually, while supply is stagnant or shrinking.
- Summer tanker rates in Pune, Hyderabad, and NCR have doubled in the last four years.
- Green building norms (IGBC, GRIHA) and most state pollution boards now mandate minimum 30–50 % water recycling for new projects above a certain size.
The result? Property buyers, hotel chains, IT parks, and factory owners are discovering that the real limiting factor is no longer land or power; it is water.
Which Sectors Can Switch to Treated Sewage Water
Almost every non-potable use can run perfectly on well-treated sewage:
- Toilet flushing in apartments, malls, airports, and offices
Largest single opportunity. An average Indian household of four uses 120–150 litres per person per day for flushing alone. A 500-apartment complex can save 2–3 lakh litres of fresh water daily. - Landscape irrigation and water bodies
Golf courses, public parks, highway medians, and society lawns in Gurugram, Noida, Bengaluru, and Pune already use treated sewage through dual plumbing networks. - Cooling tower make-up in industries and commercial buildings
Power plants, steel mills, textile units, data centres, and large office towers consume enormous volumes for evaporative cooling. Treated sewage with simple tertiary polishing works as well as (or better than) borewell water because it has lower scaling potential after proper treatment. - Construction water
Dust suppression, curing, and compaction on large sites can absorb 50,000–2 lakh litres per day — all from on-site STPs. - Vehicle washing and floor cleaning
Car wash centres, bus depots, and industrial shop-floors in Chennai and Hyderabad have switched entirely.
Process water in non-food industries
Textile dyeing, leather processing (after additional treatment), and pulp & paper units in Tamil Nadu and Uttar Pradesh are legally required to meet “Zero Liquid Discharge” and achieve 80–95 % recycling using treated sewage blended with effluents.
The Real Cost Advantage of Recycled Water
The economics are compelling in 2025:
When you look at actual delivered cost per 1,000 litres in most Indian cities in 2025, the difference is striking. Municipal water supply typically costs between ₹45 and ₹80, but it comes with frequent shortages and low pressure during peak summer months. Running your own borewell appears cheaper at ₹25–₹50 per 1,000 litres when you only count electricity and basic maintenance. Yet this ignores the rapidly falling water table and increasing risk of salinity or contamination.
Private tankers, which have become the lifeline for thousands of housing societies and commercial buildings, now charge anywhere from ₹90 to ₹180 per 1,000 litres depending on distance and season, and the supply is never guaranteed.
In comparison, producing reuse-quality water from your own treated sewage plant costs only ₹8–₹18 per 1,000 litres once the system is installed and running. This figure includes power, minimal chemicals, and part-time operator salary. More importantly, the supply is 100 % under your control, available 365 days a year, with zero transportation delays or price shocks. For most residential complexes, hotels, IT parks, and industries, this makes recycled sewage water the single cheapest and most reliable source of non-potable water available today.
A 200 KLD residential society in Pune, installed dual plumbing in 2021 and now saves ₹42–48 lakh every year in tanker bills by reusing 140–160 KLD for flushing and gardening. Payback on the extra piping cost was under 14 months.
Even smaller 40–60 KLD hotels in Jaipur and Goa report ₹12–18 lakh annual savings after switching cooling towers and irrigation to treated water.
STP Technologies That Make High-Quality Reuse Possible and Affordable
Not every STP produces water good enough for reuse. The key lies in choosing the right biological process and polishing steps:
- Attached Growth Bioreactor (AABR) systems (used in SKF Elixer Vulcan series)
Bacteria grow on fixed synthetic media instead of floating freely, resulting in 30–40 % less sludge, higher resistance to load shocks, and consistent outlet BOD <10 mg/L and TSS <10 mg/L without heavy chemical dosing. - Tertiary polishing options
- Pressure sand + activated carbon filters (standard for flushing & gardening)
- Ultrafiltration membranes (for cooling towers and construction)
- Reverse osmosis (for near-potable or ZLD industrial reuse)
- Stainless-steel modular construction
Zero leakage risk, 20+ year life, relocatable, and odour-free — critical when the plant sits in a basement or inside a housing society. - Automatic operation and IoT monitoring
Most modern 50–300 KLD plants now run with one part-time operator and remote alerts, keeping operating cost below ₹12–15 per 1,000 litres treated.
Because AABR plants produce far less sludge and need minimal chemicals, the cost of producing reuse-quality water is often lower than running an old MBBR or SBR plant that was designed only for discharge.
From Compliance to Profit Centre
In 2025, a well-planned sewage treatment and reuse system does three things simultaneously:
- Guarantees NGT and pollution-board compliance
- Cuts freshwater bills by 40–70 %
- Adds genuine resale value to the property (apartments with dual plumbing and zero tanker dependency command 8–15 % premium in Bengaluru and Pune)
The era of treating sewage as waste is over. The cities and businesses that recognise treated sewage as a reliable, local, drought-proof water source are the ones that will stay operational — and profitable — through the dry decades ahead.
Every litre reused is one litre that does not need to be extracted from an already stressed aquifer or transported across the city at ₹150 per KL.
In a water-starved India, treated sewage water is no longer wastewater. It is the new freshwater — and advanced solutions like AABR technology in STP plants make achieving this reliability easier than ever.
If you’re planning a new project or upgrading an existing facility, explore the SKF Elixer Vulcan STP product range to get a high-efficiency, compact, low-sludge treatment solution tailored for your site.
Click here to enquire about our STP systems and get expert guidance for your requirement.
Frequently Asked Questions (FAQs)
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1. How much freshwater can a typical apartment complex save with sewage reuse?
A 500-flat society generating 200–250 KLD sewage can reuse 160–200 KLD for flushing and gardening, reducing freshwater demand by 55–70 % and saving ₹35–60 lakh per year.
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2. Is treated sewage water safe for garden plants and trees?
Yes. When treated to BOD <10 mg/L and properly disinfected. It is safer than many municipal supplies because sodium and chloride levels are controlled and micronutrients actually benefit plants.
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3. What is the extra cost of dual plumbing for reuse?
₹400–₹800 per flat in new construction (separate lines for flushing). Retrofitting costs ₹1,200–2,000 per flat but still pays back in 2–4 years at current tanker rates.
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4. Can industries directly use treated sewage in boilers or processes?
After ultrafiltration or RO polishing, yes. Many textile and chemical units in Tiruppur, Vapi, and Panipat already achieve 90 %+ recycling and meet ZLD norms.
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5. How long does it take to recover the investment in a reuse-ready STP?
Most residential and commercial projects achieve full payback in 3–6 years through water-bill savings alone; hotels and industries often recover in 18–36 months.
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