Effluent tank

[AndrewG]

Building a new silage pit which will be earth banks with a small shuttered wall around the edge, tank will need to be 10000 gallons.

Looking at options for effluent tanks, the last pit I built has a steel tank, I assume an ex fuel tank but I can't find any, so looking at either concrete or a grp type tank, any other options or recommendations appreciated.

 

[S J H]

I think they have to have a standard, but I can't remember what it is, I was told that europipes sell them, or cotteril civils

 

[Pan mixer]

I made a tank bigger than that - 15 feet diameter and 12 feet deep - for my dirty water system, I took engineering advice which was simple....

Dig hole, lay a concrete base (I wish now that I had put in a low-end for the pump), lay concrete blocks - 6 inch hollows - in a circle taking care to fill the joints between the blocks properly. Keep laying the courses of blocks, backfilling with soil as you go to give you something to stand on.

Stop at ground level if you want or go a bit higher for security having concreted in the outfalls as you go.

Despite the corrosive effects of dirty water, my cheap tank is still fine after 28 years, it gets pumped out most nights by a submersible macerator pump so any groundwater leaks in although I believe that you could build the whole thing in a plastic sheet.

No idea about the rules for silage juice though or if it is even more corrosive than pig pee.

 

[MickMoor]

You can follow this link, https://www.gov.uk/guidance/storing-silage-slurry-and-agricultural-fuel-oil , it's all here:
Silos
All parts of a silo must be resistant to attack. Your silo must have:

• an impermeable base extending beyond any walls
• impermeable drainage collection channels around the outside, flowing into an effluent tank

The base must comply with:

• British Standard 8007:1987 and British Standard 8110-1:1997 (for concrete bases)
• British Standard 594/EN 13108-4:2006 (for hot-rolled asphalt bases)

If your silo has walls they must withstand wall loadings set in British Standard 5502-22:2003+A1:2013..

Ask your manufacturer, or check the mannual that came with your equipment, to find out if it meets these British Standards.

Effluent tanks
Your silo must have an effluent collection system.

If all parts of an effluent tank are above ground, the tank must be constructed to resist attack from silage effluent for at least 20 years with maintenance. If any part is below ground it should be impermeable for at least 20 years without maintenance. You’ll be asked to prove your tank is suitable, eg with a manufacturer’s guarantee.

You can store silage effluent and slurry together if your tank has enough capacity and is built to withstand both types of effluent. However, mixing slurry can give off gases that are lethal to humans and livestock, and you must never put silage effluent into an under-floor slurry store.

Capacity
The minimum capacity rules for effluent tanks should give you at least 2 days’ storage at peak flow. However, it’s up to you to ensure you’ve enough capacity to avoid the risk of pollution.


Silo capacity Minimum effluent tank capacity
Up to 1,500 cubic metres 20 litres for each cubic metre
Over 1,500 cubic metres 30 cubic metres, plus 6.7 litres for each cubic metre of silo capacity over 1,500 cubic metres