Sewage Treatment Plant (STP) Manufacturer & Supplier in Bengaluru

A Sewage Treatment Plant (STP) is a facility that processes domestic and municipal wastewater to remove contaminants before the treated water is discharged or reused. The process involves physical, biological, and chemical treatment stages that remove suspended solids, organic matter, nutrients, and pathogens.

Modern STP systems use technologies including MBBR (Moving Bed Biofilm Reactor), MBR (Membrane Bioreactor), SBR (Sequencing Batch Reactor), and conventional activated sludge processes — each suited to different capacities and site conditions.

In India, STPs are mandatory for residential societies above 20,000 sqm built-up area, commercial complexes, hotels, hospitals, and all industrial facilities discharging domestic effluent — as per CPCB norms and local Pollution Control Board regulations.

Bengaluru's STP market is shaped by two things most cities do not deal with at the same scale: a large stock of gated-community apartments built specifically around IT campuses, and a genuine water-stress problem that makes treated wastewater reuse a financial decision, not just a compliance one. BWSSB tanker water costs have pushed many Whitefield and Electronic City societies to size their STP for maximum flushing and landscaping reuse rather than the compliance minimum.

KSPCB inspection has also become noticeably stricter around Peenya and Bommasandra over the last few years, and a number of our Bengaluru enquiries now come from older societies whose plants were built to a lower standard than current KSPCB norms require and are being asked to upgrade.

Tech park campuses around Whitefield and Electronic City add a third category — commercial STPs sized for a daytime-only occupancy pattern that looks nothing like a residential flow curve, which changes how the plant should be sized and staffed.

Bengaluru's wastewater system is under strain from sheer growth. Lakes such as Bellandur and Varthur have been the focus of long-running pollution concern, groundwater has dropped in many neighbourhoods, and tanker water is a large and rising cost for apartments. Karnataka's rules respond by requiring apartment buildings to treat their own sewage, and the pollution board has acknowledged that enforcing reuse of the treated water is difficult in practice.

The practical problems are specific. A KSPCB official has said that even large complexes with parks and lawns reuse only about 40 to 50% of their treated water in-house, so many societies end up with surplus water and no outlet. Retrofit is hard: older apartments built with a single plumbing network have no dual lines for flushing. KSPCB guidelines also discourage placing a plant in the basement of residential towers because of odour, noise and vibration, so plants must go under driveways or in separate structures away from flats.

How Optima solves it: we design the plant for the whole water balance, not just treatment. That means sizing flushing, landscaping and cooling use up front, planning dual plumbing for new buildings and practical retrofit routes for old ones, locating blowers away from flats, and advising on how surplus treated water can be used or sold under the state's recent rules.

The Karnataka State Pollution Control Board (KSPCB) requires Consent to Establish before construction and Consent to Operate after commissioning. Its rules require an STP for apartment buildings with more than 20 units or built-up area of 2,000 sq m or above, and its guidelines also cover educational institutions and large development projects. Separately, the Bangalore Water Supply and Sewerage Board (BWSSB) amended its sewerage regulations in March 2016 so that new and existing apartment buildings above 20 units connected to its network must install STPs.

KSPCB's STP guidelines add design rules: a dual plumbing arrangement for toilet flushing with treated water, blowers kept away from residential units, the plant preferably under a driveway, and no placement in the basement of apartment towers. Reported reuse-grade standards for Bengaluru are strict, around BOD 10 mg/L and TSS 10 mg/L, though the board has changed treated-water norms and fees over time, so check the current consent. The state has also moved to allow the sale of surplus treated water, which gives apartments an outlet.

Projects above 20,000 sq m also need environmental clearance, and hospitals face additional biomedical-waste obligations. We design to the figures in your consent.

Bengaluru is one of the few cities where we recommend treated water reuse as a cost argument first and a compliance argument second. With BWSSB tanker rates what they are, an MBR-based STP that produces reuse-grade water for flushing and landscaping typically pays back its higher upfront cost within a few years for a mid-size Whitefield or Electronic City society, purely on the reduction in tanker dependence.

Tech park and commercial campus STPs need a different sizing approach entirely. Occupancy peaks sharply on weekdays between roughly 9 am and 7 pm and drops close to zero on weekends, so a plant sized like a residential system either runs underloaded most of the time or struggles during the workday peak. We size these systems around the actual daily occupancy curve provided by the facility team rather than a flat per-person estimate, which is standard practice for residential design but not accurate for a campus.

Sizing examples. A 24-unit apartment building, just above the 20-unit threshold, houses about 108 residents at 135 litres, uses roughly 15 KLD and returns about 12 KLD, so a compact 15 KLD plant is enough. A 400-flat gated community with about 1,800 residents uses roughly 243 KLD and returns around 194 KLD, which points to a 200 KLD plant. A tech park with 8,000 staff at 45 litres uses about 360 KLD and returns roughly 288 KLD, with strong weekday peaks.

Which technology where. For small 20 to 100-unit buildings, a compact MBBR package fits narrow plots. MBR suits tech parks, hospitals and premium communities that want treated water for flushing and cooling towers, but remember surplus output must have a use. SBR fits large campuses and townships in Whitefield, Sarjapur Road and Electronic City with variable load. Units in Peenya, Bommasandra and Doddaballapur need an ETP for process wastewater; only staff and canteen sewage goes to the STP.