Slurry safety

Slurry safety

Safety advice from Teagasc ahead of upcoming busy time for many farmers and contractors who will be emptying slurry tanks before the 15 October deadline.

16 August 2020

Over the next few weeks many farmers and contractors will be busy emptying slurry tanks before the October 15th deadline. Mixing and spreading slurry are high risk activities. Drowning and gas poisoning together with the potential of crush injuries from machinery are the main risk areas.

Francis Bligh and Tom Fallon from Teagasc offer some detailed advice on staying safe around slurry.

Children and older farmers

Children and the elderly are at particular risk from slurry related accidents. Health and Safety Authority data show in the period 2010-2019, 5% of child fatal accidents on farms were caused by drowning/gas. In the same period 6% of deaths to elderly farmers were caused by drowning/gas. Only persons involved in the job should be present. Children must be supervised in a safe play area.

Toxic gasses

Microorganisms help break down the slurry and make the nutrients more available but this process also produces toxic gasses. Carbon dioxide, ammonia, methane and hydrogen sulphide can be released in high concentrations when agitation commences. Hydrogen sulphide is a very dangerous gas. It smells like rotten eggs at low concentrations but you cannot smell it at high concentrations. One breath at this level can be lethal. Methane is a flammable gas and farmers have experienced fires or explosions when this gas came in contact with a spark. Avoid smoking, welding and cutting metal close to slurry tanks.

Evacuate and ventilate

Before starting the job take some time to plan and prepare. Make sure farm pets are put into a secure area. Inform all family members and other people that may be around the farm that slurry agitation is taking place. Make sure all the animals have been removed from the shed. Open up all doors and air flaps to provide good ventilation. If the weather is calm and there is very little air flow delay agitation to a later time or to a different day. It is good practice to have another person present during agitation. For at least the first 30 minutes after agitation commences stay well clear of the area around the agitator and do not allow access to the shed.

Indoor agitation points

Mixing slurry using agitation points inside the shed is highly dangerous and should be avoided.

What are the options or remedies for farmers with indoor agitations points or a combination of indoor and outdoor agitation points? The first three options are all eligible for grant aid under TAMSII

Option 1: Install outdoor agitation points

Tanks can be extended to provide an agitation point/s outdoors.

Option 2: Install a slurry circulation pipe

A fixed slurry circulation pipe is used to pump slurry from an outside agitation point to a location within the slurry tank to aid circulation of the slurry. Details of this can be found in DAFM Specification S123 (see: ). To work well the slurry should be easily pumped and be of reasonable uniform consistency. For animals on a low DMD diet it is advised to start the winter by placing 0.3 to 0.6m of water at the bottom of the tank. This system is still relatively unproven but may be a viable option in some situations where appropriate agitators and slurry pumping equipment is available.

Option 3: Install a slurry aeration system

This system periodically pumps air through a series of pipes that are placed at the base of the tank. As the air bubble rises to the surface it churns the slurry thereby mixing it. This system removes the need to use mechanical agitators and lowers the likelihood of gas build up. This system is expensive to install but the running costs are low. It is important to note that this system may contradict the national requirement to reduce gaseous losses from slurry especially ammonia.

Option 4: Slurry additives

There are many additives on the market that will assist the agitation process. The feedback from farmers that have used these additives is very positive.

Teagasc advisers can advise on these options and on associated TAMSII grant applications.

Useful tips to reduce accidents when spreading slurry:

  • Has the tractor and slurry tanker been serviced recently
  • Check tyre pressure in both tractor and slurry tanker and the braking system
  • Check attachment mechanism of tanker for wear.
  • Clean windows on the tractor, check mirrors, put cones/traffic warning system on the road
  • Cut back vegetation at gate entrances to improved visibility
  • Can you adjust field openings to avoid having to stop on public roads to open gates? (or perhaps they can be opened in advance of the spreading operation)
  • Check field conditions and avoid spreading on steep ground where the surface has recently become wet

The Health and Safety Authority (HSA) have produced a number of videos focused on safety with slurry:

Authors: Francis Bligh Teagasc Health and Safety Specialist and Tom Fallon Farm Buildings & Infrastructure Specialist.