Campuses and townships
Treat sewage on site and reuse the water for gardens.
- Universities and schools
- Residential townships
- Industrial colonies
RESEARCH PARTNERSHIP / 13
Field provenDelivered by Rispri Labs
BIO-STP nature-based sewage treatment.
Plants and microbes do the work.
Rispri Labs delivers BIO-STP, a nature-based sewage treatment plant that uses a settling chamber, an engineered wetland and an aquatic plant biofilter instead of blowers for most of the treatment. Low energy, built for monsoon surges, and designed to catch microplastics and endocrine disruptors that conventional STPs miss.
RESEARCH TO REALITYRispri Labs research collaborations
What it means for you
Sewage treated by gravity, plants and microbes.
Low energy
Gravity flow and plants replace blowers for most of the treatment.
Monsoon-ready
The settling chamber buffers surges, including stormwater.
Biomass
Plants and microalgae can become biofertiliser.
Performance
Built on how rivers actually recover.
Field studies of how a river recovers after it passes a city shaped the design. They found 2.6 times more microplastics in urban wetlands than in the river itself, and that human activity explained 82.4% of the variation in water quality. BIO-STP uses the same processes a healthy wetland uses, engineered and sized for your sewage.
- 3stages
- Settling chamber, engineered wetland and aquatic plant biofilter
- 2.6×
- More microplastics found in urban wetlands than in the river
- 82.4%
- Of water-quality variation explained by human activity
- NABL
- Treated water quality verified by our accredited laboratory
The microplastic and water-quality figures are from field studies of a river downstream of a city. Treated water quality on your plant is verified by our NABL-accredited laboratory.
Challenge and response
The problems this solves.
- 01The challenge
Conventional STPs run blowers around the clock, and the power bill decides whether they keep running.
How we solve itGravity flow, plants and microbes do most of the treatment, with far less blower use.
- 02The challenge
Monsoon stormwater floods small STPs and washes sludge out.
How we solve itA serpentine settling chamber buffers surges, with equalisation and overflow control.
- 03The challenge
Microplastics and endocrine disruptors pass through most STPs.
How we solve itAdsorbent media, plants and microbes in the wetland are chosen to target them.
- 04The challenge
Untreated drains feed ponds and lakes and undo restoration work.
How we solve itA modular BIO-STP treats the drain before it reaches the water body.
How it works
The treatment train, stage by stage.
Sewage flows by gravity through three stages.
- 1
01 · Serpentine settling chamber
Removes grit and solids and buffers surges, including monsoon stormwater.
- 2
02 · Engineered wetland
Chambers with adsorbent media, plants and microbes remove nutrients, metals, microplastics and endocrine disruptors.
- 3
03 · Aquatic plant biofilter
Microalgae and plants polish the water; the biomass can become biofertiliser.
Use cases
Where BIO-STP delivers.
Hotels and resorts
A treatment plant that looks like a garden, not a machine room.
- Resorts
- Eco-lodges
- Highway hotels
Decentralised municipal sewage
Treat sewage close to where it is made, without long sewer lines.
- Small towns
- Peri-urban wards
- Villages
Drains feeding ponds and lakes
Stop sewage before it reaches a pond or lake.
- Lake restoration
- Amrit Sarovar ponds
- Urban nallahs
Treated water reuse
Use the treated water where the rules allow.
- Landscaping
- Toilet flushing
- Groundwater recharge
Verified by our NABL lab
Inlet and outlet are tested so the plant is shown to meet its consent.
- BOD, COD and TSS
- Nutrients and coliforms
- Seasonal checks
Comparison
How it compares.
| Factor | Conventional STP | Rispri solution |
|---|---|---|
| Treatment driver | Blowers and mechanical aeration | Plants and microbes, with gravity flow |
| Energy | Continuous blower power | Low; blowers replaced for most treatment |
| Microplastics and endocrine disruptors | Not targeted | Targeted by wetland media, plants and microbes |
| Monsoon surges | Often washed out | Equalisation and overflow control |
| Layout | Fixed plant | Modular stages added as flow grows |
| By-products | Sludge for disposal | Biomass that can become biofertiliser |
Standards and regulations
Designed around the rules that apply to you.
We design each system to meet your consent conditions and the regulations for your sector, and our laboratory reports against them.
- Environment (Protection) Rules, 1986STP discharge standards notified by MoEF&CC in 2017.
- NGT orders on STP standardsStricter treated-sewage limits set by the National Green Tribunal.
- CPHEEO Manual on Sewerage and Sewage Treatment Systems, 2013Design guidance for sewage treatment.
- National framework on safe reuse of treated waterGuidance on reusing treated sewage.
Industries served
Built for the sectors that need it most.
Why Rispri
Proven technology. Industrial delivery.
Field-proven technology
A proven, field-tested technology from our research collaborations with IIT Bombay, IIT Kharagpur and ICT Mumbai.
Tested on your stream
Our accredited laboratory characterises your water or waste before design and verifies results after.
Engineering since 1999
The team that builds ETPs, STPs and ZLD plants across India takes each solution from pilot to full scale.
One accountable partner
Design, supply, installation, commissioning, operation and testing under one contract.
Questions
Frequently asked questions.
What is BIO-STP?
BIO-STP is a nature-based sewage treatment plant. Sewage passes through a serpentine settling chamber, an engineered wetland and an aquatic plant biofilter, where settling, adsorbent media, plants and microbes clean it.
How is it different from a conventional STP?
A conventional STP relies on blowers to aerate the sewage. BIO-STP relies on plants and microbes and gravity flow for most of the treatment, targets microplastics and endocrine disruptors, handles monsoon surges with equalisation and overflow control, is modular and yields biomass.
Does it meet discharge standards?
It is designed to meet the standards in your consent to operate, and our NABL-accredited laboratory tests the treated water to show it does. For conventional mechanical treatment, see our sewage treatment plants.
How much energy does it use?
Much less than a blower-driven STP. Gravity flow and plants replace blowers for most of the treatment, so pumping is the main power use.
What happens in the monsoon?
The serpentine settling chamber buffers surges, including stormwater, and the plant has equalisation and overflow control so the wetland is not washed out.
Does it remove microplastics?
The engineered wetland is designed for it. Its adsorbent media, plants and microbes target microplastics, metals, nutrients and endocrine disruptors.
How much space does it need?
More open area than a compact mechanical STP, because plants do the work. We size it after a site survey, and the stages are modular.
What happens to the plants?
Microalgae and plants from the biofilter are harvested, and the biomass can become biofertiliser.
Is the technology proven?
Yes. BIO-STP is a field-proven, nature-based treatment approach. Each project starts with a survey and a pilot sized for your flow, and our NABL-accredited laboratory verifies the treated water quality.
Research partnerships
More solutions from our partnerships.
THE NEXT STEP
Prove it on
your own site.
Tell us about your sewage flow and site. We will test the sewage, size the stages and propose a pilot.
Request a pilot