When farm livestock are indoors their muck accumulates indoors. It’s valuable but hazardous.
Slurry is a smelly, semi-liquid mixture of muck and urine. If the floor’s hosed down, for example in a milking parlour, slurry is thinner because the muck has been mixed with water.
Here in Yorkshire people are proud to say that ‘where there’s muck there’s brass’. When this gets said about animal muck, the point is that muck and slurry are valuable as fertiliser for the land. But they can pollute groundwater and rivers. And they give off fumes including methane, carbon dioxide, ammonia and the most lethal slurry gas: hydrogen sulphide. So slurry management must comply with regulations.
Typically on a dairy farm, it’s part of the daily routine to scrape slurry into a reception pit below ground level. The pit is covered by a lid of concrete or stout bars.
From the reception pit, slurry is pumped up and discharged into a much larger, above-ground slurry tank. Tanks like this are familiar sights on livestock farms. They can store as much as a year’s slurry. In the tank, the slurry separates into a solid crust on top of the liquid fraction. To mix it, ready for moving it to a muck spreader, an outlet pipe is opened so that the slurry pours back into the reception pit. From there it’s recirculated by pumping it to the above-ground slurry tank again.
The season for spreading muck on the land is usually winter or spring. When that season comes around, slurry from the tank is pumped into a muck spreader. Then the spreader is towed behind a tractor to the field where its contents are discharged. It’s a smelly job and I’ve heard of complaints when this was done upwind of somebody’s house on Christmas Eve!
Slurry is in the news this week after a tragic accident. The terrible story is still breaking but we hear that the people who died were in the underground reception pit. There they didn’t drown. They were poisoned by the fumes from the slurry.
Science on the Land 