Sequencing batch reactors (SBR)

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Residential model of the Rewatec Solido SBR sewage treatment plant

What is a sequencing batch reactor?

A sequencing batch reactor (SBR) treats wastewater in optimized batches. It uses proven biological processes to remove contaminants. The result is exceptional performance with minimal energy consumption.

Our range of Rewatec SBR systems takes these design principles and hones them for your requirements.

We offer compact sewage treatment plants for homes and cottages, including our Solido and Solido Smart models. For business and communities, our in-house engineers design modular and single-tank systems according to your project's unique specifications.

No matter which solution you choose, the Rewatec SBR has the versatility to keep pace with your needs.

All installations can be adapted to population changes or periods of non-use. Plus, their treatment parameters can be personalized to reduce energy consumption or to meet new regulations in your area.

Where are our SBR systems used?

Compact Rewatec SBR models are most often a solution for:

  • primary residences
  • seasonal cottages
  • small businesses
  • campgrounds and parks

Larger-scale Rewatec SBR systems are commonly used for:

  • municipal and industrial treatment plants
  • leachate treatment for landfills and technical landfills
  • agri-food processing plants
  • residential developments

How do our SBR systems work for homes and cottages?

Rewatec SBR

Wastewater from the property runs into a main drainage pipe that flows into the Rewatec SBR.

The system uses time-controlled aeration cycles to treat wastewater. These cycles break down solids and provide oxygen to microorganisms that feed on organic pollutants.

After aeration, remaining solids (including microorganisms) sink to the bottom of the tank. They become what is known as activated sludge. A portion of this material always stays in the tank to treat the next batch of wastewater.

Rewatec Solido Smart SBR sewage treatment plant for homes and cottages in Portugal, Spain, and Morocco.

Discharge and final dispersal

When solids settle on the bottom of the tank, treated wastewater naturally forms at the surface. A lifting mechanism (either an airlift or a mechanical pump) discharges this wastewater from the tank so that it can be safely returned to the environment.

System controls

Our SBR models for homes and cottages come equipped with an electronic control panel. The control system ensures that treated wastewater flows out of the Rewatec SBR at a controlled rate.

To simplify set-up, optimized parameters are automatically loaded when the number of building occupants is entered in the control panel.

For sporadic usage or periods of non-use, an "economic mode" is available. This mode reduces aeration by 50% for a total of 30 days, which maximizes energy efficiency and reduces operating costs. After the 30-day period, the control system automatically returns to its previous settings.

How do our SBR systems work for businesses and communities?

Rewatec SBR system for a large-scale municipal wastewater treatment project in Canada.


Primary treatment tank or fine screen

In typical installations, wastewater first flows into a primary treatment tank. This tank allows liquids to separate from solids. Solids that settle on the bottom of the tank are called primary sludge. They are removed from the tank by a septic pumper as often as needed.

In some cases, a fine screen takes the place of the primary treatment tank. It provides a simple barrier that removes solids from wastewater before they can move downstream.

Equalization tank (if needed)

After primary treatment, liquids flow into an equalization tank. This tank collects wastewater from daily peak-use periods and sends measured doses to the Rewatec SBR.

When the Rewatec SBR is specifically designed for continuous flow, the equalization tank is not needed.

Rewatec SBR

Inside the Rewatec SBR, intermittent aeration cycles break down solids and provide oxygen to microorganisms that feed on organic wastewater pollutants.

After aeration, solids (including microorganisms) sink to the bottom of the tank and become what is known as activated sludge. A portion of this material always stays in the tank to treat the next batch of wastewater. The rest is extracted and returned to the primary treatment tank or a sludge storage tank.

During periods of very high flow, the system can shift from a batch-flow strategy to a continuous-flow strategy with intermittent discharge. This versatility eliminates the need to overdesign the system to cope with fluctuating flow rates, and it has no effect on treatment performance.

Receiving system and final discharge

As solids settle on the bottom of the Rewatec SBR, treated wastewater forms at the surface. A floating decanter with a solids-exclusion feature drains this wastewater so that it can be safely released into the environment.

SBR maintenance for homes and cottages

Protect your investment in your compact Rewatec SBR by having it regularly inspected and pumped by a qualified professional.

The frequency of service depends on the size of your tank, the amount of wastewater your property generates, and the environmental regulations in your area. It is best to speak with a local professional to determine the service that is right for you.

When your service provider visits your property, they should:

  • check for cracks and leaks in the tank
  • measure the scum and sludge layers
  • pump the tank, if needed
  • clean the effluent filter in the outlet pipe
  • keep and update maintenance records for your system
  • explain any areas of concern and recommend next steps

SBR services for businesses and communities

Our team of in-house experts and professional partners is here to guide you through every step of your business or community project.


  • engineering support to guarantee the best solution
  • help with technical drawings and diagrams
  • advice for electromechanical equipment
  • control panel design, including electrical diagrams

Construction and installation

  • dedicated project managers
  • fast answers to all questions
  • on-site support to ensure high-quality installations
  • real-time troubleshooting


  • commissioning by a qualified technician
  • verification of installation success
  • rapid responses to any areas of concern


  • full support from our process and mechanical experts
  • maintenance services from local technicians
  • remote support available

Find near you

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