The storage of slurry
This General Binding Rule (GBR) applies to the storage of slurry.
Authorisation level
General Binding Rule (GBR)
Rules
The storage of slurry is covered by General Binding Rules. If you intend to carry out this activity, and you comply with the rules set out below, your activity will be authorised. You don’t need to apply to SEPA for an authorisation.
If you carry out an activity under this authorisation you must comply with the rules. It is an offence if you do not comply with the rules.
If you cannot comply with the rules, you will need a different type of authorisation.
General Binding Rule (GBR) for the storage of slurry
Where slurry is produced on the farm by housed livestock from dungsteads or from dirty yards, the slurry must be stored in a slurry storage system, liquid digestate storage system, or slurry bags which have sufficient capacity to store the total quantity of slurry likely to be produced in—
- 26 weeks by housed pigs, or
- 22 weeks by housed cattle,
taking account of any additional inputs to or exports from the storage as described in paragraph (c),
the total quantity of slurry referred to in paragraph (a) is to be calculated by adding up the figures produced for each type of livestock, as applicable, in accordance with the formula for housed pigs or housed cattle, contained in regulation 7(2) of the Action Programme for Nitrate Vulnerable Zones (Scotland) Regulations 2008(a),
(a) S.S.I. 2008/298, amended by S.S.I. 2008/394, S.S.I. 2009/447, S.S.I. 2011/228, S.S.I. 2012/360, S.S.I. 2013/123, S.S.I. 2014/373, S.S.I. 2015/376 and S.S.I. 2021/412.
in calculating the minimum storage capacity necessary to comply with paragraph (a), the following figures must be included in respect of the relevant 26- or 22-week period—
- the quantity of any rainfall (including any fall of snow, hail or sleet) that is likely to enter the system (directly or indirectly) including from dungsteads, silage pits or dirty yards,
- the quantity of any cleaning water that is likely to enter the system or slurry bag,
- the likely quantity of any imported slurries and liquid digestate added to the system or slurry bag,
- the quantity of any slurry exported off farm,
where slurry is imported onto the farm, there must be sufficient storage capacity on the farm to store the quantities imported during periods when application is not authorised under activity 18 of this Chapter or would not comply with the requirements of the Action Programme for Nitrate Vulnerable Zones (Scotland) Regulations 2008,
the capacity of any facility used for the temporary storage of slurry before it is transferred to a slurry storage tank must be the equivalent of at least 1.5% of the minimum on farm storage capacity in accordance with paragraph (a),
the slurry storage system must—
- comply with paragraphs (g) to (l),
- where constructed, or substantially reconstructed or enlarged, on or after 1 September 1991, comply, in addition to paragraph (f)(i), with paragraphs (m) and (n),
- if new (including systems constructed from used materials), substantially reconstructed or enlarged, on or after 1 January 2022, have a life expectancy of at least 20 years with proper maintenance, from its construction, reconstruction or enlargement,
the base and walls of any slurry storage tank, any channels and reception pit, and the walls of any pipes, must be impermeable (except where the conditions in paragraph (j) are complied with) and free from any cracks or structural defects,
where slurry flows into a channel before discharging into a reception pit, and the flow is controlled by means of a sluice or valve, the capacity of the reception pit must be sufficient to store the maximum quantity of slurry which can be released by opening the sluice or valve,
the slurry storage tank, channels, pipes, valves, and reception pit must be operationally maintained to be free of any structural defects during their lifecycle,
where the walls of the slurry storage tank are not impermeable—
- the base of the tank must extend beyond its walls and be provided with channels designed and constructed so as to collect any slurry which may escape from the tank,
- the tank must have adequate provision to collect, drain and store slurry from the channels to a slurry storage system,
where the slurry storage tank or reception pit is fitted with a drainage pipe—
- there must be two valves in series on the pipe and each valve must be capable of stopping the flow of slurry through the pipe and must be kept shut and locked in that position when not in use,
- sub-paragraph (i) does not apply in relation to a slurry storage tank which drains through the pipe into another slurry storage tank of equal or greater capacity or where the tops of the tanks are at the same level,
where a slurry storage system has walls which are made of earth, the system must not be filled to a level which allows less than 750 millimetres of freeboard, and in all other cases the slurry storage tank must not be filled to a level which allows less than 300 millimetres of freeboard,
the base and walls of any slurry storage tank, channels and reception pit, valves, and the walls of any pipes, constructed, or substantially reconstructed or enlarged, on or after 1 September 1991 must be protected against corrosion in accordance with paragraph 7.2 of the Code of Practice on Buildings and Structures for Agriculture, BS 5502- 50:1993+A2:2010(b),
(b) Published by the British Standards Institution on 15 April 1993, last updated in 2010 (ISBN 978-0-580-71245-6).
the base and walls of any slurry storage tank and any reception pit constructed, or substantially reconstructed or enlarged, on or after 1 September 1991, must be capable of withstanding characteristic loads calculated on the assumptions and in the manner as set out in paragraph 5 of the Code of Practice on Buildings and Structures for Agriculture, BS 5502- 50:1993+A2:2010,
any slurry storage system, constructed, or substantially reconstructed or enlarged, on or after 1 January 2022, which has walls made of earth, must be lined with an impermeable sheet material which, with proper maintenance, slurry cannot permeate for a period of at least 20 years,
a slurry storage system constructed on or after 1 January 2022 must not be situated within 10 metres of any surface water or opening into a surface water drain which slurry could enter into if it were to escape,
a slurry bag may only be used to store slurry if—
- the bag is constructed of impermeable material of sufficient strength and structural integrity such that it is unlikely to burst or leak in its ordinary use, and
- it is situated in a bund which complies with the following requirements—
- the bund must be of at least equivalent capacity to the slurry bag,
- the bund must be lined with an impermeable sheet material which, with proper maintenance, slurry cannot permeate for a period of at least 20 years,
- the bund must have a means of removing rainwater, and
- other than as necessary to allow rainwater to be removed, the base and walls of the bund must not be penetrated by any valve, pipe or other opening,
where a slurry storage system (including a reception pit or channels) is to be constructed or to be substantially rebuilt or enlarged—
- the operator must give notice to SEPA of the works no later than 30 days prior to commencing the works,
- the notice under sub-paragraph (i) must be accompanied by an engineering plan for the works to be carried out,
- the operator must retain the engineer’s final sign-off certificate for the works for the lifetime of the slurry storage system, for inspection by SEPA on request,
slurry may be stored in a liquid digestate storage system which complies with the rules for activity 34 of this Chapter in relation to the storage of liquid digestate.
Activity 34 of this chapter activity 34 in Chapter 2, Schedule 9 of The Environmental Authorisations (Scotland) Regulations.