Marsh Industries Car Wash Silt Trap

A silt trap is a pre-treatment tank installed before an oil separator or wash-down separator at vehicle wash bays etc. Its job is to catch coarse solids (grit, sand, sediment, etc.) so they don’t enter downstream equipment which could clog it or reduce its efficiency. 

Marsh’s silt traps are part of their Hydroil range of wash-down / silt trap / separator products.

Model	Capacity (litres)	Length (mm)	Width (mm)	Height (mm)	Outlet Invert	Other features
CST1	~ 830-1,050 L (depending on spec)	~ 1,165-2,110 mm	~ 680-720 mm	~ 1,060-1,140 mm	~ 110 mm	Uses galvanised steel grating for the top; heavy-duty body; guaranteed 25 years with design life 50 years.
CST2	~ 1,570-2,180 L	same footprint width & height pattern as CST1 across models
CST3	~ 2,300-3,200 L
CST4	~ 3,400-4,230 L

 

Regulations & Standards

Marsh’s wash-down separators and silt traps are tested / certified, particularly under BS EN 858 parts 1 & 2 when oil separation is involved. Although silt traps themselves are more about solid removal, they are part of the overall drainage / pollution control scheme. 

Use of wash-down separators or silt traps is often a legal requirement for commercial wash-bays etc. due to risk of contamination (soil, oil, detergents etc.

Pros & cons

Pros:

Protects downstream oil separators and foul/surface water systems from silt, reducing maintenance, blockages.

Durable build (25 year guarantee), strong grating, resistant to ground conditions.

Helps comply with environmental regulations.

Cons / considerations:

Must be sized correctly for the wash bay / flow, otherwise silt will settle less efficiently or overflow.

Need regular maintenance / emptying (silt build-up). If neglected, performance degrades.

The cost and space required increase with capacity.