Skip to product information
1 of 2

12 Person Marsh ENCO Sewage Treatment Plant (Gravity)

Regular price
£2,430.00 (£2,025.00 ex VAT)
Regular price
Sale price
£2,430.00 (£2,025.00 ex VAT)
Est. delivery: 5-7 working days

Take advantage of the brand new ENCO sewage treatment plant range by Marsh. This sewage treatment plant comes with a gravity outlet and is suitable for dwellings with up to 12 people. The Marsh ENCO range is budget-friendly, whilst also providing high-quality results. The treated effluent is exceptionally clean, and safe to discharge into a soakaway or watercourse.

This Marsh ENCO sewage treatment plant is tested to BSEN12566:3 and CE-marked which makes it compliant with the latest Building Regulations requirements, as well as environmental standards. It has a class-leading effluent quality of 11.5:19.2:8.4 (BOD:SS:NH4) ensures discharges well within national consent standards.


  • Near silent energy efficient compressors
  • Effective 3 stage chamber system for separation & retention of solids which improves final effluent quality
  • Standard or shallow options enable suitability for all applications
  • High specification bio-media (310m3 per m2 ) & membrane diffusers ensure even circulation. 
  • Internal continuous recirculation (from final to primary chamber) to provide higher effluent quality whilst balancing flow over 24 hour period or periods of intermittent use
  • Integral lifting eyes for improved on-site handling
  • Unique 'keying-in' lip to assist anchoring into granular or concrete surround


Rest assured that our Marsh sewage treatment plants come with a 10-year structural warranty and have a 50-year design life.

Installation Service:

If required, we can also provide you with an installation service at an additional cost (location dependent). Contact us on 0121 351 3230 to find out more.

View product data sheet here.

Image for illustrative purposes only. The ENCO tank is grey in colour.

Full Description

This Marsh ENCO sewage treatment plant is for domestic properties with up to 12 people. It comes with a gravity outlet.

Take advantage of the brand new ENCO range from Marsh Industries! This range offers exceptional value for money for off mains sewage treatment systems.

Due to the 3 stage process of treating effluent and recirculation, these sewage treatment plants offer the most environmentally sustainable solution to off mains drainage.

The Marsh ENCO Sewage Treatment Plant is an excellent choice for offering value for money. In addition to the anaerobic absorption occurring in the essential settlement tank (as septic tanks), the ENCO unit permits the cleared up water to go into a second “air circulation” chamber where it is processed to expel the broken up constituents. Here oxygen-consuming microscopic organisms, upheld by diffused air and versatile media, guarantee full treatment is accomplished before the treated emanating (and ‘sloughed off’ microscopic organisms) stream to the last settlement chamber before release.

This Marsh ENCO plant treats effluent to British and European Standards to an impressively clean standard. This makes it safe to be discharged back into the watercourse whilst following all appropriate regulations. Our Marsh ENCO tanks can be manufactured with either a gravity or pumped outlet.

Our ENCO domestic sewage treatment plant comes with lifting eyes as standard to make unloading and installation faster and safer. It's innovative design allows it to self-level on the base and use unique pipe connections to ensure efficient installation.

What are the benefits of the Marsh ENCO Sewage Treatment Plant?

• No moving parts
• Low running and maintenance costs
• Faster and safer to install due to lifting eye
• Tested and certified to BSEN12566-3
• 50-year design life
• 10-year structural guarantee

Installation is also available for this product.

Technical Specification

No. of people: 12

Height (mm): 2139mm

Outlet: Gravity

Outlet Invert: 625mm

Inlet Invert: 550mm

Width (mm): 1912mm

Length (mm): 2860mm

Outlet Type: Gravity outlet

Installation Service

We can also offer an installation service for our stormwater attenuation, rainwater harvesting, water storage and sewage treatment solutions. Get in touch here.

Contact Us

Our team of experts are available and ready to speak to you. You can contact us or call us directly on 0121 351 3230. Available Mon-Friday 8am-5pm.

Further questions?

Our team of specialists are here to help. We install many of our products so can provide real-world advice. We also offer a free take-off service if required.

Make an enquiry

Our Guides and Advice