ZEXCORP delivers end-to-end sewage treatment plant solutions for apartments, hospitals, hotels, and industries across Kolkata and West Bengal. From process design and WBPCB compliance to fabrication, installation, and long-term O&M — we handle everything so you don't have to.
☎ Get a Free STP QuoteFinding a reliable STP company in Kolkata that combines genuine environmental engineering expertise with end-to-end project execution is not easy. Most vendors in the market are equipment traders or fabricators who assemble standard tanks without understanding the process chemistry behind sewage treatment. The result is chronic performance issues — high BOD in treated water, excessive sludge, foul odour, and WBPCB non-compliance notices.
ZEXCORP Services Private Limited is different. We are a Kolkata-headquartered environmental engineering and EPC consultancy that designs, builds, commissions, and operates sewage treatment plants from the ground up. Our engineering team brings hands-on experience with brewery wastewater, pharmaceutical effluents, textile ETP, and large residential STP systems — not just textbook knowledge.
Whether you need a new STP for your apartment complex in Salt Lake, a retrofit of your existing plant in Howrah, or a comprehensive STP AMC in Kolkata with guaranteed treated water quality, ZEXCORP is equipped to deliver. We work across the full spectrum of treatment technologies — MBBR, SBR, MBR, ASP, and FBBR — and select the optimal process based on your inlet characteristics, space constraints, budget, and reuse requirements.
Did you know? Under KMDA building rules, all residential complexes in Kolkata with more than 20,000 sq ft of built-up area are required to install a sewage treatment plant. Non-compliance can lead to connection denial, penalties, and legal action from WBPCB.
Six reasons Kolkata's leading builders, industries, and housing societies trust us with their sewage treatment plants.
We start every project with a detailed wastewater characterization, mass balance, and process simulation. Our designs are sized to handle actual peak loads, monsoon inflow, and seasonal variations — not just nameplate capacity.
Every STP we build meets or exceeds WBPCB/CPCB discharge norms. We handle the entire compliance journey: CTE application, design approval, commissioning reports, CTO filing, and ongoing quarterly monitoring.
Our trained STP operators are available round-the-clock. We offer comprehensive O&M packages and AMCs that include routine maintenance, chemical dosing, lab testing, performance reporting, and emergency breakdown response.
We have hands-on experience with high-strength wastewater from breweries (BOD 3000+ mg/L), pharmaceuticals, textiles, food processing, and chemical manufacturing. This industrial depth makes residential STP design straightforward.
We are not locked into one technology. Our team designs and builds MBBR, SBR, MBR, conventional ASP, and FBBR systems. We select the technology that best fits your project — not the one that gives us the highest margin.
Our advanced STPs integrate IoT sensors and telemetry for real-time monitoring of flow, pH, DO, turbidity, and blower status. Plant managers and compliance officers get live dashboards and automated alerts via our NEXUS platform.
We work with all major sewage treatment technologies and recommend the right one for your specific project requirements.
The most popular choice for Kolkata apartments. Bio-media carriers provide massive surface area for microbial growth. Compact, low-maintenance, handles load fluctuations well. Ideal for 10–500 KLD capacity.
Fill-and-draw batch process with excellent nitrogen and phosphorus removal. Single-tank design saves space. Best for medium-capacity plants (50–300 KLD) with predictable inflow patterns.
Premium technology combining biological treatment with ultrafiltration membranes. Produces near-RO quality permeate suitable for direct reuse. Highest CAPEX but lowest footprint and best output quality.
The proven conventional technology for large-capacity STPs (500+ KLD). Reliable and well-understood. Requires more space and higher energy than newer technologies but delivers consistent performance.
Advanced fixed-film technology with excellent BOD removal efficiency. Sand or GAC media supports high biomass density. Suitable for high-strength wastewater and space-constrained industrial applications.
Technology selection is never one-size-fits-all. Our process design starts with characterizing your inlet wastewater (BOD, COD, TSS, pH, Oil & Grease, nitrogen, phosphorus) and understanding your site constraints:
| Parameter | Typical Domestic Sewage | WBPCB Discharge Limit | Reuse Standard |
|---|---|---|---|
| BOD (mg/L) | 200–300 | ≤ 30 | ≤ 10 |
| COD (mg/L) | 400–600 | ≤ 250 | ≤ 50 |
| TSS (mg/L) | 200–400 | ≤ 50 | ≤ 20 |
| pH | 6.5–8.5 | 6.5–9.0 | 6.5–8.5 |
| Oil & Grease (mg/L) | 10–30 | ≤ 10 | ≤ 5 |
| Fecal Coliform (MPN/100mL) | 106–108 | ≤ 1000 | ≤ 230 |
Based on these parameters, available space, budget, energy costs, and treated water reuse plans, we prepare a detailed techno-commercial comparison of 2–3 suitable technologies before finalizing the design. Read our detailed technology comparison: MBBR vs SBR — Which Is Better for Your STP?
From luxury apartment complexes to heavy industrial plants, our STP solutions are engineered for every application.
Residential apartment complexes represent the largest segment of STP installations in Kolkata. KMDA mandates STP for buildings exceeding 20,000 sq ft built-up area. We have designed and installed STPs for housing societies ranging from 50 to 2,000+ flats across Salt Lake, New Town, Rajarhat, EM Bypass, and South Kolkata.
Our residential STP designs prioritize minimal footprint, low noise, odour control, and treated water reuse for gardening, car washing, and toilet flushing — reducing freshwater consumption by 30–40%. Read more: Complete Guide to STP for Apartment Complexes in Kolkata.
Industrial wastewater presents unique challenges — high BOD/COD, variable pH, dissolved solids, heavy metals, and toxic compounds. Our industrial experience spans brewery ETP (BOD 3,000+ mg/L), pharmaceutical wastewater, textile dyeing effluent (high colour and TDS), food processing waste, and chemical manufacturing. We design combined ETP+STP systems that treat both process effluent and domestic sewage in a single integrated plant, optimizing CAPEX and operational costs.
End-to-end sewage treatment plant solutions — from concept to commissioning and beyond.
Wastewater characterization, technology selection, process flow diagrams, P&ID, equipment sizing, civil structural design, electrical single-line diagrams, and detailed engineering drawings.
In-house and partner fabrication of MS/SS/FRP tanks, filter presses, clarifiers, aeration systems, chemical dosing skids, MBBR bio-carriers, and pre-fabricated compact STP modules.
Civil construction, mechanical erection, piping, electrical wiring, instrumentation, wet testing, biological seeding, performance stabilization, and WBPCB commissioning report preparation.
Full-time or periodic O&M services with trained operators, chemical management, routine lab testing, equipment servicing, WBPCB compliance reporting, and 24/7 emergency support.
Comprehensive AMC packages covering preventive maintenance, consumables, quarterly NABL lab reports, wear-part replacement, bioculture dosing, and performance guarantees on treated water quality.
Upgrade old ASP/extended aeration STPs to high-efficiency MBBR or MBR. Add tertiary treatment for reuse. Install IoT monitoring. Increase capacity without expanding civil footprint. All without stopping ongoing operations.
Navigating the West Bengal Pollution Control Board's regulatory framework can be daunting. ZEXCORP provides complete WBPCB compliance support as part of every project: CTE (Consent to Establish) application, design document preparation, commissioning test reports, CTO (Consent to Operate) filing, ongoing quarterly environmental monitoring, and representation during WBPCB inspections. We ensure your STP is fully compliant from day one. Learn more: Why Most ETPs Fail Their First WBPCB Inspection.
We serve clients across the Kolkata Metropolitan Area and key industrial zones throughout West Bengal.
Beyond the Kolkata metropolitan area, we serve industrial clients across West Bengal including Durgapur (steel and power sector), Haldia (petrochemical and port), Siliguri (tea processing), and Asansol (mining and manufacturing). Our field teams are based in Kolkata with rapid deployment capability to any site in the state.
One of the most common questions we receive is: "How much does an STP cost in Kolkata?" The answer depends on several factors, but here are realistic budget ranges based on our recent projects:
| STP Capacity | Technology | Typical Application | Estimated Cost |
|---|---|---|---|
| 5–10 KLD | Compact MBBR | Small apartment complex (30–50 flats) | ₹3–6 Lakh |
| 20–50 KLD | MBBR / SBR | Mid-size society (100–250 flats) | ₹8–20 Lakh |
| 50–100 KLD | MBBR / SBR | Large complex / Hospital | ₹18–35 Lakh |
| 100–300 KLD | SBR / MBR | Township / Commercial | ₹30–75 Lakh |
| 500+ KLD | ASP / MBBR / MBR | Industrial / Municipal | ₹75 Lakh – 2+ Cr |
Note: Costs are indicative and include equipment, fabrication, installation, and commissioning. Civil construction, electrical, and site-specific modifications are additional. Contact us for a detailed project-specific quotation.
Common questions from our clients about sewage treatment plants in Kolkata and West Bengal.
Tell us about your project and we'll prepare a detailed techno-commercial proposal within 48 hours.
💬 WhatsApp Us NowKMDA requirements, technology options, cost estimates, and compliance checklist for residential STP installations.
Head-to-head comparison of the two most popular sewage treatment technologies with pros, cons, and cost analysis.
Common compliance failures, what inspectors look for, and how to ensure your treatment plant passes on the first try.