Marsh Civils

Marsh Civils


in fully accredited water and wastewater product solutions

As a trusted UK water and wastewater solution provider and a support team with extensive civils experience, we can help you and your team deliver project confidence.

  • Fully accredited and certified water and wastewater treatment solutions
  • High quality British manufacturing
  • Flexible production capacity
  • BIM/CAD materials support
  • Wide-ranging civils project experience
  • End-to-end customer service

Early engagement with the Marsh Civils team can bring product optimisation and significant cost savings.

Our experts are available to discuss your project and, in conjunction with our unique Gaia Sége process design software, we can provide you with the optimal solution for your site requirements.

Marsh accreditation

Contact our experts to find out how we can help you deliver project confidence


Marsh Civils product banner link

BIM/CAD library

We host a wide range of product downloads for architects, engineers, consultants and specifiers, including BIM files (RFA files), DWG CAD files and other supporting documentation is available to download here.

We also host a full technical library featuring all product information, specifications and certification here.

BIM / CAD files for architects, civil engineers and specifiers are available to download here


Gaia Sége process design software

Developed by Marsh Industries, the unique Gaia Sege process design software uses core information to accurately calculate and tailor key variables ensuring total optimisation for individual applications.

These precise calculations provide assurance to consultants, engineers, specifiers and contractors that the system is specifically designed to meet the appropriate standards of regulatory bodies.

Sewage treatment plants
For sewage treatment plants, the software uses established core process equations to accurately calculate and tailor key variables ensuring total processing optimisation for Biological Oxygen Demand (BOD), Total Suspended Solids (TSS) and Ammonia (NH4) reduction and removal.

Gaia Sege software also uses ‘British Water Flows & Loads’ data to calculate initial flows and loadings whilst also calculating peak flows and levels.

The programme can also calculate accurate sludge generation and storage on a daily basis, dependent upon final effluent standards required, ensuring the optimisation of primary chambers, individual clarifiers, diffused oxygen feed and final settlement chamber.

Pump chambers
Gaia Sege utilises current building regulations to calculate precise storage chamber sizes. Pump systems are determined by using friction head loss calculations based on minimum self-cleansing velocities in order to specify the best possible pump(s) for the application.

Grease traps
Appropriate grease trap sizes are generated by accounting for the amount of grease and flow generated from the grease producing facility whilst providing adequate retention time befitting of these variables.

Water attenuation tanks
Marsh Industries’ rainfall storage sizing programme, Gaia Storm Dammer, can simulate the calculated flood storage required for any prolonged period within a set geographic area (ie, 1 in 5 year or 1 in 100 year rainfall).

Download our new product specification brochure


Contact the experts in civils / commercial water and wastewater treatment


Speaking to experts in their field, such as those at Marsh Industries, provides us with confidence that the correctly sized tank is supplied and installed. Their systems are innovative and generally on quick lead times.

We have installed Marsh STPs for the last 4 years, robust products with fantastic technical support from their Regional Sales director.

Reliable products, prompt response on after sales issues, and flexible delivery schedules when required.

Designing and manufacturing a wide range of solutions from sewage treatment plants and cesspools to grease management systems and oil separators from our bases in Northamptonshire and Somerset, our products are fully type-tested and accredited including third party material integrity and fire testing.