In the final instalment of our three-week series on the main slurry storage options covered in TAMS II, we are looking at the option of building an over-ground circular slurry store.Over the past two weeks, we looked at the costs of installing a concrete slurry tank, a geomembrane-lined slurry store (lagoon) and the possible grant aid a farmer may receive from a successful TAMS II application.
In the final instalment of our three-week series on the main slurry storage options covered in TAMS II, we are looking at the option of building an over-ground circular slurry store.
Over the past two weeks, we looked at the costs of installing a concrete slurry tank, a geomembrane-lined slurry store (lagoon) and the possible grant aid a farmer may receive from a successful TAMS II application.
Concrete slurry tanks have the advantage of being easily upgraded and slatted for animal housing in the future. However, they are usually the more costly option, especially when large-scale slurry storage is required.
Lagoons can be a more cost-effective solution for slurry storage, but planning permission for lagoons can be difficult to achieve with some county councils.
Another option for slurry storage on farms is the over-ground circular slurry store and they are also covered in TAMS II.
The majority of farmers who erect over-ground slurry stores already have some form of slurry storage on the farm and use the over-ground tank to expand capacity.
The main advantages and possible disadvantages of over-ground slurry stores are listed below.
Advantages
Speed and ease of construction (can take just one week to erect).No major dig-out costs involved. Very little excess clay to take care of.A safer option compared with open slurry stores that require safety fencing.Disadvantages
Slurry usually needs to be pumped from a reception tank to the over-ground tank.In a green field site, a reception tank would have to be built, adding significantly to the cost. The reception tank should have at least two weeks’ slurry storage to save the amount of times a farmer has to pump his slurry to the over-ground tank.A propeller agitator usually needs to be purchased to fit inside the tank. Over-ground circular store example
Aidan Kelly from Agri Design and Planning Services in Newcastle, Clonmel, Co Tipperary, assisted us again this week with plans for two different sizes of over-ground tanks that farmers may install.
Figure 1 shows the plans of a tank designed to hold 16 weeks of slurry for a 100-cow herd. The tank has capacity for 134,000 gallons or 610m2 of slurry. The tank has a radius of 7.26m and is three rings (4.27m) high.
Table 1 shows the Department’s reference costs for building this size of over-ground tank and the maximum grant aid available for a successful TAMS II applicant.
This tank costs a total of €35,235 excluding VAT to build. Included in this cost is the floor of the tank, a ladder and platform, pipe work from the reception tank to a jetter, a jetter, slurry release valves and a mixer. A slurry reception tank is not included in the cost.
Under the Young Farmer Capital Investment Scheme (YFCIS) in TAMS, the maximum grant an applicant could receive if building this size of tank is €21,141.
A non-qualifying YFCIS farmer could apply for grant aid through the Animal, Welfare, Safety and Nutrient Storage Scheme, where the maximum grant would be €14,094.
Figure 2 shows the plans of a tank designed to hold 16 weeks of slurry for a 200-cow herd. The tank has capacity for 268,800 gallons of slurry or 1,221m2. The tank has a radius of 9.82m and is three rings high (4.27m).
Included in this cost is the floor of the tank, a ladder and platform, pipe work from the reception tank to a jetter, a jetter and a mixer. A slurry reception tank is not included in the cost.
Table 2 shows the Department’s reference costs for building this size of tank and the maximum grant aid available for a successful TAMS II applicant. In total, this tank, which suits a 200-cow herd, costs €49,593 excluding VAT.
Under the YFCIS in TAMS, the maximum grant an applicant could receive if building this size of tank is €29,755. A non-qualifying YFCIS farmer could apply for grant aid through the Animal, Welfare, Safety and Nutrient Storage Scheme, where the maximum grant would be €19,837.
Main specifications
According to the Department, all the specifications are the responsibility of the store contractor, or in accordance with the store contractor’s instructions. Farmers planning to install an over-ground slurry store through TAMS must use a contractor from the approved Department list, which can be found on the Departments website under S122A.
The main specifications for over-ground slurry stores is listed on the Department’s website under S122.
Excavation
All top soil and soft material must be excavated to a minimum depth of 150mm, or down to solid stratum, and the excavated material must be removed from site to a suitable area.
Hardcore must be compacted in 150mm layers using a suitable vibrating or heavy roller. The compacted hardcore must be extended a minimum of 300mm in each direction beyond the edge of the base. All hardcore must be blinded over by fine sand or by a 50mm layer of blinding concrete finished smooth.
A 1,000-gauge polythene membrane must be laid on the finished hardcore with 600mm overlaps. The overlaps must be sealed with suitable adhesive tape. The polythene must be brought up on the inside of the timber or steel formers around the outer edge of the ring beam.
In cases where fill is purchased for use under concrete, it must be certified to EN 13242:2013 and meet all the Department’s requirements. This material must also be used as the top 300mm of any backfill around stanchion foundations.
Ring beam
A ring beam must be constructed around the outer edge of the store, on which the store wall shall be constructed. The ring beam must be constructed to the store contractor’s specification.
Suitable fixing points must be installed in the ring beam for the fixing of the store walls. The concrete in the ring beam must also be vibrated using a poker vibrator.
Store floor
Steel mesh must be laid in all floors. The mesh must have a concrete cover of at least 40mm. The concrete must be thoroughly compacted using a vibrating screed and compaction around steel reinforcement must be carried out with a poker vibrator. The floor must be finished smooth.
Tank sides
The sides of the tank must be constructed and placed by the store contractor. All joints must be suitably sealed and certified as leak-tight by the store contractor.
The materials used in the tank sides shall be those accepted by the Department of Agriculture, Food and the Marine. If changes are made to the materials to be used in the tank sides, then acceptance must be sought from the Department for the new materials used.
Access ladders and platforms
An access ladder must be supplied to the side of the tank to enable viewing of the upper surface of the slurry in the tank. This ladder must be provided with a back safety cage. The lower 2.4m of this ladder must be removable so as to prevent unauthorised access to the top of the tank.
If agitation is to be performed using a jetter affixed to the top of the tank, then a safety platform, with safety rails, must be provided for the jetter operation. This platform must be at least 2m long by 1m wide and be fitted with toe board and safety railing. The platform must be constructed from galvanised steel and have a non-slip surface finish. At least two rails must be placed around the platform.
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