Sewer Loops Rig

Sewer Loops Rig

The test and control sewer loops rig is a unique research facility available for studies on in-sewer processes.

The test and control sewer loops rig is the first and only in the UK of this scale. The facility simulates two sewer lines fed with real wastewater that are easily accessible being completely above ground.

The rig is composed of two pipelines made of high density polyethylene (HDPE) pipe of 100 m length and 125 mm in diameter (external) with a 1% slope. Each pipeline is equipped with:

  • mixing chambers to allow dosage of external solutions or sampling;
  • an upfront butterfly valve to either close or partition the flow in the pipe;
  • removable sections allowing to monitor the condition of the inside of the pipe or to change the material of the section;
  • transparent sections for visual inspections;
  • inline sampling points;
  • inspection points for the use of CCTV camera systems;
  • an array of sensors located towards the end of the pipeline to continuously monitor the quality of the sewage for the following parameters: temperature, water depth, dissolved Oxygen, electro-conductivity, oxidation reduction potential, pH, ammonia (NH4+), turbidity. The same parameters are also monitored for the screened crude sewage feeding both lines;
  • insulating foam to minimise variations in temperature.


The uniqueness and flexibility of the facility make it an ideal location to conduct studies at large scale to deliver results to tackle some of the most challenging problems for the UK water sector. Some examples are:

  • in-sewer processes management and control (e.g. fat, oil and grease (FOG) deposit control and remediation, septicity and odour control and remediation, biofilm formation and corrosion, macro and micro pollutants transformation);
  • monitoring and control systems (e.g. sensors development and testing);
  • blockages management and control;
  • innovative approaches or technologies for sewer systems (e.g. heat exchange/recovery, innovative/alternative materials, coating, bio-augmentation);
  • environmental impact and emissions (e.g. greenhouse gas (GHG) emissions and control).


Dr Luca Alibardi

Lecturer in Separation Processes

Cranfield Water Science Institute


Prof Bruce Jefferson

Professor of Water Engineering

Cranfield Water Science Institute


Keywords: In-sewer processes; diffused emissions; fat, oil, grease (FOG); blockages; sewer heat exchange; septicity; bioaugmentation; sewer materials; online monitoring; sampling.