Hospital STP and ETP Guidelines in India

Introduction: A Hospital Is Not an Ordinary Building

A hospital looks like a large residential or commercial building from the outside. It has toilets, kitchens, laundry and cooling towers, and it produces sewage like any other. But inside, it also produces wastewater that no apartment block does: blood and body fluid contaminated water from wards and operating theatres, pathology and microbiology laboratory effluent, chemical and disinfectant waste, radiology developer and fixer solutions, dialysis reject and pharmacy residues.

This changes the rulebook. A hospital's liquid waste is covered by the Bio-Medical Waste Management Rules, 2016 and their amendments, in addition to the general environmental standards, consent from the State Pollution Control Board and, for larger projects, environmental clearance conditions. Failing to manage it can spread pathogens, harm treatment plants downstream and attract notices and compensation.

The terms STP and ETP are often mixed up in hospitals. In broad terms, an STP treats the sewage from toilets, washing and kitchens. An ETP treats special streams, such as infectious liquid waste and laboratory effluent, before they join the sewage, or sometimes the combined flow. Many hospitals end up with a combined arrangement: pre-treatment and disinfection for infectious and chemical streams, followed by a main biological plant.

This guide explains the standards in plain language, how to build a design basis, which treatment steps a hospital plant needs, how to manage disinfection and records and what to ask a supplier. It is written for hospital administrators, facility managers, biomedical engineers and consultants. Trity Enviro designs hospital STP and ETP systems, and this guide draws on that work. Confirm the exact limits that apply to you with your SPCB.

Which Rules and Standards Apply

Bio-Medical Waste Rules and Liquid Waste Standards

The Bio-Medical Waste Management Rules, 2016, notified in March 2016 and amended in 2018 and 2019, require health care facilities to treat liquid waste before discharge. Schedule II sets treatment and disposal requirements, including that infectious liquid waste be pre-treated and disinfected before mixing with other wastewater, and that the combined discharge conform to the standards for liquid waste. Those standards, as quoted in official documents and summaries, include:

• pH between 6.5 and 9.0
• Suspended solids up to about 100 mg/L
• BOD up to about 30 mg/L
• COD up to about 250 mg/L
• Oil and grease within a stated limit
• A bioassay test, with a minimum survival of test organisms

The rules also have conditions for small facilities. Health care facilities with fewer than ten beds, for instance, have simpler options, and non-bedded occupiers must disinfect infectious liquid waste before disposal. Check the current text, since the rules have been amended more than once.

STP Norms, Consent and Clearance

Many SPCBs also apply the general STP norms to hospital sewage, and several hospital plant suppliers quote values like BOD of 10 mg/L, COD of 50 mg/L, TSS of 10 to 20 mg/L and faecal coliform of 100 MPN/100 mL, following the NGT's STP order for stricter categories. Whether these or the BMW Rule standards bind a particular hospital depends on its consent and on whether it discharges to a sewer, a drain or the ground. Read your consent, and design to the stricter value if in doubt.

Recent regulatory changes add confusion. In 2025, a CPCB circular on category reclassification affected how some hospitals are classified, and an analysis of that circular noted that a lower pollution category does not remove the duty to meet the liquid waste parameters of the BMW Rules. Larger hospital projects of 20,000 square metres or more of built-up area may also need environmental clearance with STP conditions, as explained in our guide to whether an STP is mandatory for your building. Consent to establish and operate are covered in our CTE and CTO guide.

Building the Design Basis

Water Use and Wastewater per Bed

Hospital water use is much higher per person than in residences. A common planning figure for bedded hospitals is in the region of 450 litres per bed per day, with outpatients, staff, kitchens, laundry, air conditioning and cooling towers adding to it. Use the figures in the National Building Code and your state's norms, and confirm them with actual metering if the hospital exists.

A worked example. A 200 bed hospital might use around 90 KLD for beds at 450 litres per bed, plus roughly 20 to 30 percent for outpatients, staff and services, giving about 115 KLD. Assuming about 80 percent becomes wastewater, the plant flow is about 90 to 95 KLD. Add a peak factor for the morning and evening periods, and add the cooling tower and laundry streams if they are connected. A design of around 100 to 120 KLD with an equalization tank is a reasonable starting point. For the full method, see our guide on how to calculate STP capacity. This is only an illustration: use your own metered data and the norms that apply.

Segregating Special Streams

Good hospital design starts with segregation. Keep these streams separate until they have been dealt with:

• Infectious and body fluid wastewater from wards, operating theatres, labour rooms and mortuary: pre-treat and disinfect at source
• Laboratory effluent from pathology and microbiology: collect, neutralise and disinfect, and keep strong chemicals out of the drain
• Radiology fixer and developer: silver recovery or removal by an authorised agency, and not to the STP
• Mercury, cytotoxic and pharmaceutical waste: manage as hazardous or biomedical waste, not as wastewater
• Kitchen and laundry: grease trap and equalization before the plant
• Dialysis reject water: relatively clean but high in salts and disinfectant residuals, which may affect the biology

Anything that is not wastewater should not go through the plant. Disinfectants and antibiotics in large quantities can inhibit bacteria and damage biological treatment.

The Treatment Train

Pre-Treatment, Biological Treatment and Tertiary Polishing

A typical hospital plant includes:

1. Screening and grit removal for rags, plastics and sand
2. Equalization tank with mixing, sized for the peak, as explained in our guide to equalization tank design
3. Biological treatment: extended aeration, MBBR, SBR or MBR. MBBR and MBR are popular in hospitals because of their compactness and stable performance. See our comparison of MBBR vs SBR vs MBR
4. Secondary clarification, with tube settlers if space is tight
5. Tertiary treatment: pressure sand and activated carbon filters, and optionally ultrafiltration for reuse. See our tertiary treatment plant page
6. Disinfection, discussed below

Nitrogen limits may require an anoxic zone, as explained in our guide to ammonia and nitrogen removal in STP. Our dedicated pages on hospital STP and hospital ETP describe the options.

Disinfection, Sludge and Reuse

Disinfection is not optional in a hospital. The pathogen profile includes bloodborne viruses, enteric bacteria and drug-resistant organisms. Chlorination, UV and ozone are the common choices. Chlorine dosing needs adequate contact time and a measurable residual, and it must be controlled to avoid excess chlorine in the discharge or reuse water. UV needs low turbidity water, so it follows filtration. Using two methods in series is sometimes done for the infectious pre-treatment stream and the final outlet.

Sludge from a hospital plant, especially from the pre-treatment of infectious liquid waste, should be stabilised and disinfected, for example with lime, and handled as the BMW Rules and your SPCB require. Ask your SPCB how it classifies the sludge, and keep records of disposal through authorised channels.

Reuse of treated water for flushing, gardening and cooling towers lowers the hospital's water bill, but it needs reliable filtration and disinfection and clear labelling of reuse pipes, and it should never reach areas where patients, food or sterile processes are involved.

Operation, Records and Cost

Monitoring and Documents Inspectors Ask For

Hospitals are inspected, and accredited hospitals also face audits under quality standards. Keep:

• A daily logbook: flows, DO, pH, chlorine residual, blower hours, chemical use
• Monthly outlet tests for pH, BOD, COD, TSS and faecal coliform, or as required by your consent, from an accredited laboratory
• Records of segregated liquid waste handling under the BMW Rules
• AMC reports, operator training records and equipment calibration records
• Consent to operate, authorisations and returns

Our guide on the STP operation and maintenance checklist gives a logbook format that hospitals can adapt.

Questions to Ask Before You Order

• Which standards did you design to, and how do they match my consent?
• What is the design flow, peak factor and basis, and what metered data did you use?
• How are infectious and laboratory streams segregated and pre-treated?
• What disinfection method and residual control do you propose?
• How is sludge handled, and what does the SPCB require?
• What footprint and noise control does the plant need near wards?
• What operation, maintenance and emergency support do you provide?

Trity Enviro's sewage treatment plant and effluent treatment plant range covers hospitals of all sizes, and an annual maintenance contract or operation and maintenance service keeps the plant dependable.

Industry Comparison / Operational Parameter Table

Why Choose Trity Enviro

Trity Environ Solutions is an ISO 9001:2015 certified and QCI-approved hospital sewage treatment plant and effluent treatment plant manufacturer and supplier in India, delivering robust, high-efficiency systems engineered for CPCB and SPCB regulatory compliance.

Every installation is supported by pan-India Annual Maintenance Contract and Operation and Maintenance services.