Slurry separation

[Fools Gold]

Having just followed a trailer load of solids along the the road that were to be tipped in a field gateway it got me wondering what exactly the point of slurry separation is?
It seems to me to just create yet another product to be handled and involves yet more machinery (separation unit, pumps etc) which will go wrong and cost money and hassle to fix, surely the old argument of being able to spread the liquid fraction on grazing ground without tainting has less credence with the advent of dribble bars and trailing shoes? Increased Storage space is another reason I once heard but surely with the cost of all the kit involved in separation some extra storage space would be a viable option?
Anyone care to explain their reasons for separation? I’d be interested to hear them and learn something!
Cheers

 

[deleted user 837354]

Having just followed a trailer load of solids along the the road that were to be tipped in a field gateway it got me wondering what exactly the point of slurry separation is?
It seems to me to just create yet another product to be handled and involves yet more machinery (separation unit, pumps etc) which will go wrong and cost money and hassle to fix, surely the old argument of being able to spread the liquid fraction on grazing ground without tainting has less credence with the advent of dribble bars and trailing shoes? Increased Storage space is another reason I once heard but surely with the cost of all the kit involved in separation some extra storage space would be a viable option?
Anyone care to explain their reasons for separation? I’d be interested to hear them and learn something!
Cheers

The main bonuses from separating slurry as I understand it:

The solid fraction can be carted and stacked anywhere, totally 'legally', also being dry(ish) it is easier to cart about. This all saves storage space.

Second, your remaining liquid is all totally solid free and so no crust forms and it contains far less sediment to settle on the bottom meaning you can now have a plastic lined lagoon. Being 'solid free' it is also very easy to pump and spread.

In reality these benefits come at a cost and with the required complexity of most separators- a piece of machinery that is basically playing with muck day in day out and all that goes with that.

Spreading separated solids is a dream mind as it is usually pretty friable- like compost.

 

[Beef farmer]

The main bonuses from separating slurry as I understand it:

The solid fraction can be carted and stacked anywhere, totally 'legally', also being dry(ish) it is easier to cart about. This all saves storage space.

Second, your remaining liquid is all totally solid free and so no crust forms and it contains far less sediment to settle on the bottom meaning you can now have a plastic lined lagoon. Being 'solid free' it is also very easy to pump and spread.

In reality these benefits come at a cost and with the required complexity of most separators- a piece of machinery that is basically playing with muck day in day out and all that goes with that.

Spreading separated solids is a dream mind as it is usually pretty friable- like compost.

Let me just stop you there.... solid free liquid is more difficult to pump. Water is harder to pump/get a decent flow than slurry.

@lazy farmer may shed some light as he separates.

For spreading behind cows it would be a dream. We don't stir the pit when doing so. But it results in a thick sludge that is really difficult to handle

 

[frederick]

Let me just stop you there.... solid free liquid is more difficult to pump. Water is harder to pump/get a decent flow than slurry.

@lazy farmer may shed some light as he separates.

For spreading behind cows it would be a dream. We don't stir the pit when doing so. But it results in a thick sludge that is really difficult to handle

Please explain the fluid dynamics of that.
It may be harder to get good pressure at an umbilical because the flow rate is greater and less pressure but water will always flow faster through an umbilical pipe than slurry. Simply less resistance.

 

[Beef farmer]

Please explain the fluid dynamics of that.
It may be harder to get good pressure at an umbilical because the flow rate is greater and less pressure but water will always flow faster through an umbilical pipe than slurry. Simply less resistance.

Its the impeller having nothing to bite onto to push it on its way.
Our umbilicle man says that when he gets called to pump a flooded river or such for the EA that even over a short distance he can get the flow. Our slurry being self feed is very thin and often leaves the same comment here.
@Sid could testify, he knows a bit about the slurry job, whereas I know nowt

 

[Boysground]

I have been separating for a few years now. It has a number of pros and cons. I have deep sand beds and so the sand is a massive issue. The layout of the farm does not make movement of anything easy, it is bisected by a main A road and a river. My tanker runs every week moving or spreading slurry.
The sand is the biggest issue it destroys anything mechanical it touches, the wear on the separator is high but the sand stays with the liquid portion settles quickly which means we can more it to another lagoon and more importantly my umbilical contractor will put it through his pump. We put separated liquid on wheat this reduces my fertiliser spend on the wheat.

I also have more muck than I need, I have 4 or 5 people who regularly have separated solids. The 2 main ones will have had over 1000t each in the last year. If I call either a fleet of trailers appear, they are both arable farmers so they don’t need anything more special than a hired muck spreader to spread it.

It reduces my nvz storage requirement and with planning issues it’s difficult to enlarge the lagoon at the dairy.

The separator is getting worn now and will be replaced in the next few years. The cost of running isn’t huge as the whole auto scraper and separator system runs on 4 small electric motors.

It has taken a lot of learning and alteration to get to the system we have now. Never believe any company that says their kit is sand proof. I won’t be going back to not separating the pros massively outweigh the cons on this farm.

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[Bramble]

The running costs of our separators is fairly low, a small electric motor each. Budget for a new screen every 18 months. Pumping the liquid fraction is much easier, and faster, than pumping slurry. The biggest running cost is the electric for a 20hp electric motor that we run to pump up to the separators

Its expensive compared to just shoving slurry in a lagoon, but it makes things a lot easier for us

 

[deleted user 837354]

Ah yes, the other bonus of separated solids- arable farmers will happily take it.

 

[deleted user 837354]

Let me just stop you there.... solid free liquid is more difficult to pump. Water is harder to pump/get a decent flow than slurry.

@lazy farmer may shed some light as he separates.

For spreading behind cows it would be a dream. We don't stir the pit when doing so. But it results in a thick sludge that is really difficult to handle

I've been on the umbilical team and spread separated liquid before, you may be right about overall flows, I'm not really sure as I haven't done it in over a decade but the liquid easy to apply.

 

[frederick]

I have been separating for a few years now. It has a number of pros and cons. I have deep sand beds and so the sand is a massive issue. The layout of the farm does not make movement of anything easy, it is bisected by a main A road and a river. My tanker runs every week moving or spreading slurry.
The sand is the biggest issue it destroys anything mechanical it touches, the wear on the separator is high but the sand stays with the liquid portion settles quickly which means we can more it to another lagoon and more importantly my umbilical contractor will put it through his pump. We put separated liquid on wheat this reduces my fertiliser spend on the wheat.

I also have more muck than I need, I have 4 or 5 people who regularly have separated solids. The 2 main ones will have had over 1000t each in the last year. If I call either a fleet of trailers appear, they are both arable farmers so they don’t need anything more special than a hired muck spreader to spread it.

It reduces my nvz storage requirement and with planning issues it’s difficult to enlarge the lagoon at the dairy.

The separator is getting worn now and will be replaced in the next few years. The cost of running isn’t huge as the whole auto scraper and separator system runs on 4 small electric motors.

It has taken a lot of learning and alteration to get to the system we have now. Never believe any company that says their kit is sand proof. I won’t be going back to not separating the pros massively outweigh the cons on this farm.

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How are you stirring and pumping up to the separator with small motors

 

[frederick]

Its the impeller having nothing to bite onto to push it on its way.
Our umbilicle man says that when he gets called to pump a flooded river or such for the EA that even over a short distance he can get the flow. Our slurry being self feed is very thin and often leaves the same comment here.
@Sid could testify, he knows a bit about the slurry job, whereas I know nowt

Is that not more a sign of worn impeller.

 

[lazy farmer]

The problem we found with slurry is what the hell to do with it in a grazing situation.our answer was to grow maize and reseed and dump the stuff on the stubble and plough it in.
What a waste.

We have no issues pumping separated liquids and will either follow cow grazings or silage with it.
The solid element if allowed to decompose becomes a real soil enhancer and if spread lightly can be applied in between grazings or silage crops with no issues at all as it disappears within hours if your soils are alive and well.

 

[Treemover]

The problem we found with slurry is what the hell to do with it in a grazing situation.our answer was to grow maize and reseed and dump the stuff on the stubble and plough it in.
What a waste.

We have no issues pumping separated liquids and will either follow cow grazings or silage with it.
The solid element if allowed to decompose becomes a real soil enhancer and if spread lightly can be applied in between grazings or silage crops with no issues at all as it disappears within hours if your soils are alive and well.

Would you mind popping up some photos of the solid element, and on silage ground?

 

[lazy farmer]

Would you mind popping up some photos of the solid element, and on silage ground?

Will do

 

[rusty]

I have been using a separator for 15 years . For the last 10 years we have also had our own umbilical gear with an underground main that goes under 2 roads allowing us to umbilical 360 of our 400 acres at home. Solids are trailered to our wholecrop ground, some of which is 7 miles away.
For us it's much more efficient to cart the solids to the away ground as you are not shifting anywhere near as much water. The liquid goes on grazing and silage ground in spring and then after every silage cut. The separated liquid soaks in very quickly and we feel we get a better response than unseperated slurry from our Youngstock slats that gets tinkered on with a dribble bar. The other advantage of having separated slurry for the umbilical system is that we don't have to blow out the pipes or underground main when we finish pumping.
I would agree with @Beef farmer that having a bit of solids in the separated slurry helps it pump faster. We transfer from our youngstock shed directly to our main lagoon resulting in about 10% unsepearated in the lagoon and it definitely pumps better than from our small intermediate lagoon that is purely separated slurry.

 

[Fools Gold]

Thank you all very much for taking the time to reply to my OP it’s been great reading the explanations given and provided some interesting food for thought.
from my own perspective on slurry management a recent major investment in new storage capacity has allowed us to apply slurry at the correct times (housed herd on multi cut) and reduce bagged fert usage by around 1/3rd
A purchase this spring of a dribble bar for one tanker seems to have resulted in improved grass yields in the fields spread with it over the ones done at same time with a splash plate, whether the increase is enough to warrant the cost of the machine will take longer to ascertain!

 

[Boysground]

How are you stirring and pumping up to the separator with small motors

Houle piston pump. Hydraulic drive off a half horse power motor. Lifts about 6m with our setup, it cycles every 20 seconds each pump is about 40 gallons.

Had a supposedly sand proof impeller pump and destroyed it in a few weeks. Other than bushes and seals wearing we have done little else to the houle pump since it was bought.

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[Boysground]

Thank you all very much for taking the time to reply to my OP it’s been great reading the explanations given and provided some interesting food for thought.
from my own perspective on slurry management a recent major investment in new storage capacity has allowed us to apply slurry at the correct times (housed herd on multi cut) and reduce bagged fert usage by around 1/3rd
A purchase this spring of a dribble bar for one tanker seems to have resulted in improved grass yields in the fields spread with it over the ones done at same time with a splash plate, whether the increase is enough to warrant the cost of the machine will take longer to ascertain!

Ive been running a shoe on the tanker for a few years now. I’m sure it’s the best way to go, my umbilical guy uses a dribble bar and that is also good.

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[frederick]

Houle piston pump. Hydraulic drive off a half horse power motor. Lifts about 6m with our setup, it cycles every 20 seconds each pump is about 40 gallons.

Had a supposedly sand proof impeller pump and destroyed it in a few weeks. Other than bushes and seals wearing we have done little else to the houle pump since it was bought.

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Thanks piston pump was the plan but how do I avoid a 7kw stirrer in the reception pit

 

[Boysground]

I don’t stir. Can run a hydraulic driven mixer off the houle I think.


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