INDUSTRIES / HOSPITALS AND HEALTHCARE
Hospital wastewater treatment
that stops infection leaving the building.
Hospital wastewater carries far more bacteria, drug residues and disinfectants than ordinary sewage. We design, build and operate hospital STPs and ETPs with dependable disinfection, keep water safe inside the building, and test every stream in our NABL-accredited laboratory.
In short
What hospital wastewater treatment involves.
Hospital wastewater treatment is the treatment of sewage and liquid waste from wards, operation theatres, laboratories, laundry, kitchens and dialysis units so that it can be discharged or reused without spreading infection or chemicals. A hospital usually needs an STP (sewage treatment plant) for domestic-type wastewater, pre-treatment at source for laboratory and chemical liquids, and strong final disinfection (chlorine, UV or both). Under India's Bio-Medical Waste Management Rules, 2016, liquid waste must be segregated and pre-treated, and the treated effluent must meet the limits in the rules or the State Pollution Control Board's consent.
- 340–450L/bed/day
- National Building Code water demand for hospitals, the starting point for STP sizing
- 30mg/L
- BOD limit for treated liquid waste in Schedule II of the Bio-Medical Waste Rules, 2016
- 2016
- Year of the Bio-Medical Waste Management Rules that govern hospital liquid waste
- NABL
- Accredited laboratory for coliform, Legionella, BOD and COD tests on your water
Where the water comes from
Where does hospital wastewater come from?
Most of a hospital's wastewater looks like ordinary sewage. What makes it different is the small, concentrated streams mixed into it, and the very high number of disease-causing bacteria, including antibiotic-resistant ones, that patients shed. Each source needs to be understood before a plant is designed.
- Wards, OPD and staff toilets: the bulk of the flow. Faecal bacteria, viruses, urine with excreted medicines, and disinfectants from cleaning.
- Operation theatres, ICUs and casualty: blood and body fluids, antiseptics such as povidone-iodine and chlorhexidine, and heavy use of surface disinfectants.
- Pathology, microbiology and blood bank laboratories: cultures, reagents, stains, formalin and solvents. Under the 2016 rules, microbiological and laboratory waste must be disinfected or sterilised before it leaves the department.
- Laundry: often a fifth or more of water use in a large hospital, with hot water, detergents, bleach and lint. High pH and foam upset a biological plant if the flow arrives in one burst.
- Kitchen and canteen: fats, oil and grease (FOG), which need grease traps before the STP.
- Dialysis unit and RO plants: large volumes of RO reject that are clean but high in dissolved salts (TDS), plus spent dialysate.
- Radiology and imaging: where film is still processed, used fixer contains silver and must be collected for recovery, not drained. Contrast media from CT and MRI pass out in patients' urine.
How much wastewater will a hospital produce?
The National Building Code design figures are about 340 litres per bed per day for hospitals up to 100 beds and 450 litres per bed per day above that, with sewage usually taken as 80 to 90% of water used. A 200-bed hospital therefore produces in the region of 70 to 80 KLD (kilolitres per day) of wastewater, more with an in-house laundry, a medical college or a residential campus.
| Parameter | Typical raw range | Why it matters |
|---|---|---|
| BOD (biochemical oxygen demand) | 150 to 400 mg/L | The biodegradable load that sets the size of the biological stage |
| COD (chemical oxygen demand) | 300 to 900 mg/L | Higher than in household sewage because of drug residues, detergents and disinfectants that break down slowly |
| Total suspended solids | 100 to 400 mg/L | Solids shield bacteria from chlorine and UV, so they must be removed before disinfection |
| Faecal coliform | Millions per 100 mL | Indicator of disease-causing organisms; the main reason for strong disinfection |
| pH | 6.0 to 9.0, with laundry spikes | Bleach and alkaline detergents can push it high in bursts |
| Residual disinfectants and antibiotics | Variable, often low but continuous | Can slow down the bacteria in the STP and encourage antibiotic resistance |
| TDS (dissolved salts) | 500 to 2,000 mg/L, higher with RO reject | Limits reuse for cooling towers and gardens |
Rules and standards
What rules apply to hospital liquid waste?
The Bio-Medical Waste Management Rules, 2016 (MoEF&CC) require every occupier of a healthcare facility to segregate liquid waste at source and pre-treat it before it mixes with other effluent. Schedule II of the rules sets standards for treated liquid waste. The State Pollution Control Board's consent under the Water Act, 1974 may set stricter values, and the STP outlet must also meet the MoEF&CC STP standards of 2017 or the stricter values recommended by the NGT in 2019 where the board asks for them.
| Parameter | Limit |
|---|---|
| pH | 6.5 to 9.0 |
| Suspended solids | 100 mg/L |
| Oil and grease | 10 mg/L |
| BOD | 30 mg/L |
| COD | 250 mg/L |
| Bio-assay test | 90% survival of fish after 96 hours in 100% effluent |
Treatment
How a hospital STP and ETP work, step by step.
Keep chemicals and infectious liquids out at source, treat the rest biologically, then disinfect with a margin of safety. Most hospitals need one combined plant with pre-treatment units in front.
| Stage | What happens |
|---|---|
| 1. Source pre-treatment | Laboratory and microbiological liquids are disinfected or autoclaved in the department. Kitchen water passes through grease traps. Laundry water may go to its own holding tank so bleach and detergent surges are spread out. |
| 2. Screening | Fine screens catch gloves, gauze, cotton and plastic that reach drains despite segregation. Screenings are handled as soiled waste. |
| 3. Equalisation and neutralisation | An aerated tank holds several hours of flow and evens out the morning peak of ward cleaning and OT washing. pH is corrected if laundry or chemical spills push it out of range. |
| 4. Biological treatment | MBBR, SBR or MBR. Bacteria remove BOD and ammonia. A longer sludge age helps the biology cope with disinfectants and drug residues. |
| 5. Clarification | Tube settler or clarifier separates the biomass; MBR membranes replace this step and remove most bacteria physically. |
| 6. Tertiary filtration | Pressure sand filter and activated carbon filter take turbidity low, so disinfection works and some drug residues and colour are adsorbed. |
| 7. Disinfection | Chlorination with a contact tank and a measured residual, UV, or both in series. Ozone is used at some sites for added removal of residues. |
| 8. Sludge handling | Excess sludge is stabilised, dewatered and disposed of as the SPCB directs. Hospital STP sludge must not be spread on food crops without treatment. |
| Process | Best for | Treated water | Watch-outs |
|---|---|---|---|
| MBBR + sand and carbon filter + chlorine/UV | Most 50 to 500-bed hospitals, upgrades of old STPs | Meets 2017 values; NGT values with good tertiary | Disinfection fails if turbidity is high |
| SBR + tertiary + disinfection | Medical college campuses with hostels and variable flows | Very good, removes nitrogen | Needs reliable PLC and level control |
| MBR + UV | City hospitals in basements, high reuse targets | Excellent, very low solids and bacteria | Higher power and membrane cleaning; keep lint out |
| BIO-STP (nature-based) | Hospital campuses with open land, rural and district hospitals | Good, with low power use | Needs area; final disinfection still required |
BIO-STP is Rispri's field-tested, nature-based sewage treatment. It uses gravity flow and plants instead of blowers, which cuts power use for campuses with land. For hospitals it is always followed by filtration and disinfection.
Our NABL-accredited laboratory tests treated hospital wastewater for BOD, COD, TSS, oil and grease and faecal coliform, and our microbiology section tests drinking water, RO water and cooling towers for total bacteria, coliforms and Legionella.
Reuse and water safety
Can a hospital reuse treated wastewater?
Yes, with care about where it goes. Treated and disinfected hospital wastewater is suitable for gardening by drip or subsurface irrigation, cooling tower make-up after softening, and toilet flushing in non-clinical blocks such as offices, hostels and staff quarters, through colour-coded dual plumbing. Avoid spray irrigation near wards and entrances, and never use recycled water in clinical areas, kitchens, CSSD or anywhere patients bathe.
Dialysis and RO reject is a different case: it is low in organic matter and bacteria-free when it leaves the membrane, so it can often go straight to flushing or gardens if its TDS allows, saving a large volume.
Water safety for patients
Patients with weak immunity can be infected by bacteria that are harmless to healthy people. WHO's guidance on water safety in buildings and on environmental health standards in health care recommends a water safety plan: map the system, find where water stagnates or stays lukewarm, set control measures and verify them by testing.
Legionella and cooling towers
Legionella bacteria grow at 25 to 45 °C in cooling towers, hot water tanks, shower heads and little-used taps, and infect people who breathe in fine spray. Good practice is to store hot water at 60 °C or more and deliver it at 50 °C or more, flush rarely used outlets weekly, clean shower heads, and keep cooling towers on a continuous biocide and scale control programme. We supply cooling tower biocides and inhibitors and test for Legionella in our microbiology laboratory.
Cost
How much does a hospital STP cost?
Cost depends on beds, laundry and laboratory load, the outlet standard, the disinfection chosen and the site. A basement MBR in a city hospital costs more per KLD than an MBBR plant on open ground.
| Wastewater flow | Typical facility | Indicative STP cost with tertiary and disinfection* |
|---|---|---|
| 10 to 25 KLD | Nursing home or clinic with 20 to 50 beds, diagnostic centre | ₹6 to 15 lakh |
| 50 to 100 KLD | 150 to 250-bed hospital | ₹18 to 45 lakh |
| 200 to 300 KLD | 500-bed hospital with laundry | ₹45 to 90 lakh |
| 500 KLD and above | Medical college campus with hostels and quarters | ₹80 lakh to ₹1.8 crore and upwards |
*Indicative 2026 ranges for equipment, electricals, tertiary filtration, disinfection and installation, excluding civil tanks, land, taxes and the dual plumbing network. MBR typically adds 30 to 60%. A separate pre-treatment unit for a large laboratory or laundry adds a few lakh. Running cost is usually ₹10 to 25 per kilolitre, mostly power, disinfectant and operator. We give a firm price after testing your wastewater and visiting the site.
What drives capital cost
- Beds, laundry and residential campus load
- Outlet standard and reuse plans
- Chlorine, UV or both, and contact time
- Basement or open-ground siting, odour control
- Standby blowers and pumps (a hospital cannot stop)
We audit hospital STPs stage by stage, fix disinfection and filtration, retrofit MBBR media into old tanks and run the plant under an annual O&M contract with monthly NABL reports for your SPCB file.
Troubleshooting
Common problems in hospital STPs, and how we fix them.
- 01The problem
Faecal coliform in the outlet is above the limit even though chlorine is dosed.
What we doBring turbidity down first, then set chlorine dose on measured demand with a proper contact tank, or add UV after filtration. Residual is logged daily.
- 02The problem
The biology dies off after heavy cleaning days or a disinfectant spill.
What we doEnlarge equalisation, agree cleaning chemical use with housekeeping, keep a longer sludge age, and re-seed with lab checks when needed.
- 03The problem
Gloves, gauze and cotton choke pumps and screens.
What we doFit fine screens with easy cleaning, add strainers on ward drains, and give a short segregation briefing to nursing and housekeeping staff.
- 04The problem
Foam and high pH from the laundry.
What we doRoute laundry water to its own holding tank, dose it slowly into equalisation, correct pH and use antifoam only where needed.
- 05The problem
Positive Legionella or high bacterial counts in a cooling tower or hot water loop.
What we doClean and disinfect the system, fix dead legs and temperatures, set a biocide programme and retest at agreed intervals.
What we offer
Water and wastewater services for hospitals.
Hospital STPs
MBBR, SBR, MBR and BIO-STP plants with tertiary filtration and dual disinfection, sized for beds, laundry and campus.
STP solutions →ETP and pre-treatment
Neutralisation and treatment units for laboratory, laundry and chemical streams before they join the STP.
ETP solutions →Microbiological testing
Coliforms, total bacteria and Legionella in treated water, drinking water, RO water and cooling towers.
Microbiology →Wastewater testing
NABL-accredited BOD, COD, TSS, oil and grease and pH tests for your SPCB reports.
Testing →Disinfection and cooling chemicals
Hypochlorite, biocides, scale inhibitors and RO cleaning chemicals, with spares for filters and softeners.
Chemicals →Softeners and RO
Soft water for autoclaves, boilers, CSSD and laundry; RO for drinking points and kitchens.
Water softeners →Buying guide
What to ask before you buy a hospital STP or ETP.
Use this list with any supplier, including us.
- Was the flow worked out from beds, laundry and campus use, or from metered water?
- Which outlet values are guaranteed, including faecal coliform, in writing?
- How are laboratory, laundry and kitchen streams pre-treated before they reach the plant?
- What disinfection is offered, what contact time, and how is the residual measured?
- Are there standby blowers, pumps and dosing units? A hospital plant cannot shut down for repairs.
- Where will treated water be reused, and how is it kept away from clinical areas?
- How are odour and noise kept away from wards and air-handling intakes?
- Who operates and tests it? Ask for a trained operator and a NABL-accredited laboratory.
Why Rispri
Treatment, water safety and microbiology in one team.
Our own NABL lab
Chemical and microbiological tests on raw and treated wastewater, drinking water and cooling towers, so design and verification come from one place.
Engineering since 1999
1,498+ plants and turnkey projects and 499+ clients across industries, hotels, hospitals and cities.
Chemicals and softeners in house
Disinfectants, biocides, RO chemicals, softeners and spares from our own catalogue.
Operate and maintain
Annual O&M contracts with trained operators and monthly reports, from offices in Jaipur, Agra and Ahmedabad. We work in collaboration with IIT Bombay, IIT Kharagpur and ICT Mumbai on low-energy treatment.
Questions
Hospital wastewater treatment FAQs.
Is an STP or ETP mandatory for a hospital in India?
The Bio-Medical Waste Management Rules, 2016 require hospitals to segregate and pre-treat liquid waste, and the SPCB consent sets outlet limits. In practice almost every hospital of meaningful size needs a treatment plant with disinfection, especially where there is no sewer leading to a working STP. Small clinics should confirm with their state board.
Does a hospital need an STP or an ETP?
Most hospital wastewater is sewage-like, so the main plant is an STP with strong disinfection. Laboratory, laundry and chemical streams need pre-treatment at source, which some boards call an ETP. Many hospitals have one combined plant with these pre-treatment units in front.
What are the discharge standards for hospital liquid waste?
Schedule II of the Bio-Medical Waste Rules, 2016 sets pH 6.5 to 9.0, suspended solids 100 mg/L, oil and grease 10 mg/L, BOD 30 mg/L, COD 250 mg/L and a fish bio-assay of 90% survival, for discharge where there is no sewer with a terminal STP. Your SPCB consent may set stricter values, including faecal coliform.
What size STP does a 100-bed hospital need?
At the National Building Code figure of 340 litres per bed per day and sewage at 80 to 90% of that, a 100-bed hospital produces roughly 27 to 31 KLD. With a laundry, staff quarters or a large OPD, 35 to 50 KLD is a safer design figure.
How much does a hospital STP cost?
As an indication, a 50 to 100 KLD STP with tertiary filtration and disinfection costs about ₹18 to 45 lakh for equipment and installation, excluding civil work. Small nursing home plants start around ₹6 lakh. We quote after testing the wastewater and seeing the site.
Is chlorine or UV better for hospital wastewater?
Both work when the water is clear. Chlorine leaves a residual that protects the reuse network; UV adds no chemicals and is effective against chlorine-resistant organisms. Many hospitals use UV followed by a small chlorine dose.
Can treated hospital wastewater be reused?
Yes, for gardens by drip irrigation, cooling tower make-up and flushing in non-clinical buildings, after filtration and disinfection. It must never be used in clinical areas, kitchens or for bathing.
How do hospitals control Legionella?
By keeping stored hot water at 60 °C or more and delivered hot water at 50 °C or more, flushing rarely used outlets, cleaning shower heads, and running a biocide programme on cooling towers with regular testing. A water safety plan along WHO lines ties these together.
Can laboratory waste go into the hospital STP?
Not directly. Microbiological and laboratory liquids must be disinfected or sterilised at source under the 2016 rules, and solvents, stains, formalin and mercury are collected as chemical or bio-medical waste. Only pre-treated, dilute washings should reach the STP.
How often should a hospital STP be tested?
Daily checks of pH, residual chlorine and turbidity by the operator, and monthly NABL-accredited tests of BOD, COD, TSS, oil and grease and faecal coliform are a sound minimum. Your consent may specify the frequency.
Related