Marsh Ensign sewage treatment plant
The Marsh Ensign sewage treatment plant is a widely used package system by Marsh Industries, designed for domestic or small commercial wastewater treatment. Here's a detailed overview:
🌟 What is the Marsh Ensign?
A single-tank, below-ground system using aeration and bio-media (Moving Bed Biofilm Reactor, MBBR) for treating domestic sewage to very high standards
Available in the Ensign:Standard and upgraded Ensign:Ultra variants, plus shallow-dig versions for constrained or rocky sites
🚰 How It Works
Primary chamber: anaerobic sludge settlement.
Aeration chamber: air-diffusers support bacteria growing on bio-media to degrade contaminants.
Final settling: separated biomass settles before filtered effluent discharges via a Polylok tertiary filter (on Ultra models) The Ultra version adds a quiet Whisspurr compressor with alarm and the Polylok filter for ~40% extra reduction in suspended solids and BOD
✅ Performance & Certification
Certified to BS EN 12566‑3/A1:2009, CE marked.
Achieves ~11.5 mg/L BOD, 19.2 mg/L suspended solids, and 8.4 mg/L ammonia—well within UK consent limits (~97% removal)
📏 Size Options
| Model | Population Equivalent (PE) | Length × Width × Height (mm) | Notes |
|---|---|---|---|
| Standard | 4–50 PE (e.g. 6, 12, 16 PE) | Varies 1620×1352×1575 to 5200×1912×2284 | Shallow versions in 4–35 PE reduce depth to ~1.6 m |
Installation options include gravity outlet or pumped outlet, and internal or external blower configuration. Risers for invert depth adjustment are available
🌿 Key Benefits
Low maintenance, robust with no moving parts in the tank.
Quiet and odour-free operation.
Easy to install (integral lifting eyes, Forsheda seals for flexibility, stabilising feet, self-levelling base)
Long structural guarantee: 25 years, with ~50-year design life
🏠 Best Suited For
Off‑mains dwellings or small commercial sites requiring compliant wastewater treatment.
Locations with space or access constraints where minimal soil excavation depth is advantageous.
Projects needing flexibility in discharge levels and equipment placement.
✅ Summary
The Marsh Ensign is a proven, efficient, low‑maintenance sewage treatment option certified to UK/EU standards. It is available in a wide range of sizes (4–50 PE) with flexible configurations for site and budget constraints. Particularly suitable where low noise, high-quality effluent, minimal excavation depth, and reliable long-term operation are needed.