Slurry Pump Longevity with Landia

Fit and forget. A phrase often used in engineering. And never truer than when applying it to slurry pumps at farms. As any reputable pump manufacturer will know, the ‘forget’ part is arguably a problem, because for all that reliability and longevity, your customer might easily ‘forget’ about that superb slurry pump that’s been working away in the pit for umpteen years without fail. It’s noticeable how when a farmer does have a problem with a pump he’ll refer to it as ‘the manufacturer’s pump’, but when it’s been as good as gold, he proudly refers to it as ‘my pump!’

Those rightly proud farmers are the ones who wisely recognised that to manage their farm’s slurry, you need a pump that is designed for purpose, especially for example, the arduous application of thick raw cow slurry. Yes, there are plenty of pumps out there at a tenth of the cost that may be able to handle some of the many other pumping tasks required on a farm, but the hassle of having to replace a cheaper, ineffective pump every six months soon becomes very tiresome, as well as bad economics.

I recently took a call from a pig farmer whose submersible Landia slurry pump finally needed some maintenance after its installation in... 1993. Wholly submerged in slurry, Landia’s two DG pumps (18.5kW) at J.E. Carter & Sons are built to handle thick and highly corrosive fluids, whilst Landia’s PODB (15kW) mixers (designed with a 2-blade clogging free propeller) benefit from a double mechanical sealing system between the electric motor and the surrounding liquid.

The pig farmer in question, Chris Carter at Strathyre Farm near Preston, said: “After 21 years, one of our Landia slurry pumps actually got to see daylight!”

“You can’t fault Landia’s slurry pumps and mixers,” added Chris, who uses the equipment to transfer pig slurry from one pit to another – and then to a 20’ high store.

“Landia’s pumps and mixers have never failed us”, he continued. They’ve been in our pits for over two decades, working away, dealing endlessly with slurry, which has to be mixed properly and also pumped over long distances”.

Getting it right, as with J.E. Carter & Sons, is always very pleasing, but without experience, and especially when it comes to hard to handle cow slurry, it is very easy for a young engineer to under or over specify. We certainly aren’t a one size fits all company, but we know our short, albeit quality time on site is little compared to the farmer who will be using his slurry equipment for many years to come. It is vital to carry out a proper evaluation, because slurry pits will vary enormously, as will, for example, what a farmer’s cows are fed on. It could be lucerne (alfalfa), or maybe grass or maize silage that will have a higher viscosity than green or cereal crops. Options can then be considered as to whether say, dry installed pumps should be installed - and at what pressures to meet the distances that are required. Factors such as rainwater and yard water also come into play, as does whether or not the cows are kept indoors or outdoors. If you want your slurry pump system to be a hassle-free operation – and who wouldn’t – then your pump supplier should be taking particular care over the determining factors such as pipework sizing, including all the bends and nuances that will go into making the pump operation something that will be more of a ‘forget’, than an ‘oh no, it’s blocked up again’ scenario. The whole system should be as user-friendly for the farmer as possible, with various options offered for installation, whether the pit is above ground or below ground.

Pipe diameter is crucial. Too small and you’re going to need more pressure to get things moving – probably a bigger, more powerful pump to do the same job that should be carried out by one half its size, which has unwanted capital and energy cost consequences. Too big a pipe diameter can result in not enough pressure. You don’t want to have to use the whole volume of the pit.

Thick raw cow slurry is very unforgiving. The only way to really shift it properly in our opinion is with an open-faced centrifugal pump. Non-return valves are a complete no-no. Suction pumps will fail eventually if not immediately. Achieving a homogenous mix is also vital. If slurry isn’t mixed properly then the water will be removed, leaving you with all the solids. Over the years we’ve lost count how many times we’ve been asked to add our pumps to farms where existing equipment can’t cope - either due to being under-specified, and/or because the pipe diameter and/or pipe-work has been inadequate.

When choosing your slurry pump system, you may also want to consider all the extras that some farm hands consider fair game to add to the pit. Our chopper pumps (which have a very non-forgiving knife system and no seals or bearings to have to replace), deal with syringes, aprons, rubber gloves and more. Tail hair can be a nightmare, so best choose a pump, which could be anything from 5.5kW to 40kW, that can do things that other pumps cannot do (i.e. a knife system that will cut solids) – and make sure you are getting the right advice about the impeller for your mixer so as to achieve an optimum homogeneity. Should you be planning to add surplus long cut silage to your slurry pit, please bear in mind that this will be a challenge to almost any pump! We now also produce specially coated pumps to deal with the increasing use of sand for bedding. Without the use of hardened materials to cope with such an abrasive material, pumps do not last very long at all.

Poor mixing and a lack of aeration can also result in farmers sometimes mocking one and other! A Stars and Stripes pattern on a field (dark green/light green), will stand out like a sore thumb, whereas slurry that has been treated correctly will soon filter down into the ground and out of sight as it begins do its job in helping the land and the crops. Slurry that has been suitably homogenized will always be more flowing and less aggressive, reaching plant roots quicker. This considerable reduction of the slurry’s aggressiveness allows it to spread at any time, even during the key growth period, without scorching the crops. It can also result in healthy savings on fertilizers.

An example of where different pumps undertake different farm applications recently saw us work in Cheshire for Grosvenor Farms, who needed to efficiently and effectively process its slurry.

Part of the Grosvenor Estate that represents the assets owned by trusts on behalf of the Grosvenor family, headed by the sixth Duke of Westminster, Grosvenor Farms is a 6,000 acre farm that produces milk, cereals and potatoes.

We worked in close conjunction with Midland Slurry Systems, who offer a turnkey operation for slurry treatment and pollution control, to provide two Landia pumps and a mixer at the Estate’s Grange Farm in Churton near Chester. A 10.82 feet length longshaft Landia MPG pump (15.0kW 4”) and a high pressure Landia DG pump (3.0kW) combine with a Landia POP mixer (5.5kW 300rpm) to mix and reduce the density of thick cattle slurry from young stock so that it can be pumped to a gantry-mounted separator. Separated liquor is held and then either returned to the reception pit for further thinning or pumped several hundred metres to a storage lagoon.

David Craven, the health and safety representative and building maintenance manager of Grosvenor Farms, said: “We have no disruption with Landia’s pumps and mixers, which are certainly built to last. They are also very capable of handling the long distances that we need to pump our slurry”.

Family-run business Midland Slurry Systems, who have been working with the Grosvenor Estate for over six years, have also teamed up with Landia at Chapel House Farm in Bruera near Chester. Here, a Landia pump is utilised to send used run-off water and wastewater from parlour washing to a reception pit several hundred yards away (via a pre-installed 4” irrigation main) to a 25 million gallon storage lagoon.

Odour reduction is another key benefit to be gained from the correct pumping and mixing of (cow) slurry, especially when it is fresh, with an 80% success rate in most cases. Pig slurry can be almost odour-free after an aeration period of 7-14 days in storage silos. On smaller farms particularly, a well designed pump and mixing system will put the slurry where it is needed, keeping all those odours (and flies!) away from livestock and the farmstead.

Landia began in 1933 as a company that designed and manufactured slurry pumps. Much has happened since then of course, including when in 1950, our founder Christian Oelgaard invented and patented the world’s first pump that could process and macerate the hard pebbles, long straw, and other dry matter found in thick slurry, and thereby prevent the potential cause of severe damage to the pump. This ‘chopper’ pump design has gone on to be used worldwide in all sorts of very arduous wastewater applications, but the ‘Grand Old Lady’ as we affectionately know her is still going strong - so although we have carried out thousands of ‘fit and forget’ installations, this is a slurry pump that will live long in engineering history.