Environmental Protection Internal Report TRAINING GUIDANCE
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N K A -S outh W£t>fc ^ \ - z o Environmental Protection Internal Report TRAINING GUIDANCE NOTES CONTROL OF POLLUTION FARM WASTE REGULATIONS October 1992 PC/W/l/92/002 Author: S B Newport Pollution Inspector NRA C.V.M. Dovies National Rivers Authority Environmental Protection Manager South West Region AGRICULTURAL TRAINING CONTROL OF POLLUTION REGULATIONS GUIDANCE NOTES ENVIRONMENT AGENCY FARM WASTE STORAGE AND DISPOSAL CONTROL OF POLLUTION (SILAGE, SLURRY AND AGRICULTURAL FUEL OIL) REGULATIONS 1991 The Control of Pollution (Silage, Slurry and Agricultural Fuel Oil) Regulations 1991 came into force on 1 September 1991. The regulations require persons with custody or control of a crop being made into silage, livestock slurry or certain fuel oil to carry out works and take precautions and other steps for preventing pollution of waters which are controlled waters for the purposes of Part III of the Water Act 1989. The regulations provide exemptions from their requirements and for the loss of those exemptions in certain circumstances. They also confer a right for appeal to the Secretary of State and provide that contravention of certain regulations is a criminal offence. The regulations are no longer new to the field staff of the National Rivers Authority. The aim of following notes and the contents supplied in this document will help field staff to draw a common approach to the use of the regulations across the South West Region. The regulations dictate that any person with custody of livestock slurry should provide a minimum of four months continuous storage unless they can demonstrate that a reduced storage capacity is sufficient without posing a risk to controlled waters. The farmer's ability to provide less than 4 months storage must be approved by the National Rivers Authority. The information required to satisfy the National Rivers Authority is compiled by the applicant in the form of a farm waste management plan. The Water Resources Act 1991 has several sections designed to prevent water pollution. Section 110 of the Water 1989 and the resulting Slurry Regulations aim to prevent pollution by slurry, silage effluent, dirty water and fuel oil by setting standards for keeping and handling substances. Facilities that farmers had before 1 March 1991 are usually exempt from these rules, but the National Rivers Authority can force farmers to improve structures if there is a significant risk of pollution being caused. A farmer has the right to Appeal on notice served on exempt structures and the National Rivers Authority must give him 28 days to do so. New, substantially enlarged, or substantially reconstructed facilities must meet the standards set out in the regulations. SBN/MWM - 3/9/92 FARM WASTE MANAGEMENT FLANS As previously mentioned, the Slurry Regulations dictate that a farm must provide four months continuous storage unless he is in possession of exempt structures which are safe or he proves to the National Rivers Authority that his proposed system of work is safe. Waste Management Plans can be presented in various forms for different systems. The National Rivers Authority find it acceptable if farmers provide waste disposal plans for individual waste characteristics, i.e. slurry or dirty water. Should a farmer wish to install a settlement tank and distribution system he must supply a plan showing: 1. Details of stocking and volumes of waste entering the system. 2. Calculations showing: a) Yard areas and other wastes draining to the L.R.I. b) Infiltration of clean water to the system. 3. Calculations showing capacities of the settlement and buffer storage area* 4. Pump output, rates of application and type of irrigator, i.e. mobile, static. 5. Farm maps for the area to be irrigated showing risk aspects (preferably in colour). 6. Diagram of buildings showing clean and foul drainage routes and exits. Individualise contaminated and clean areas. 7. Assessment of land showing soil types and slope. 8. Nitrogen loadings. 9. Contingencies. Should a' farmer wish to install a slurry storage system of less than 4 months capacity, he must supply a plan showing: 1. Details of stocking and wastes entering the system. a) Including run off from contaminated yards. b) Rainfall on the store. c) Provision to deal with liquid drainage. 2. Disposal methods for waste. 3. Calculations showing nitrogen loadings and application rates. 4. Farm map showing area to be used for disposal including risk and no go areas. a) Drained land. b) Slope. c) Watercourses. d) Trafficability and Porosity. 5. Contingencies. Should a farm's available land not be sufficient to take both categories of waste independently, then a full farm waste plan will be required showing a combination of both. When assessing a farm plan interpretation of certain structures can be unclear with relationship to the Control of Pollution (Silage, Slurry and Agricultural Fuel Oil) Regulations 1991. The following will be of some help to you. a) A Store - A structure which contains a minimum of two days storage of waste. b) A Reception Pit - A receiving store normally accompanied by larger containment (NOT A MULTI SETTLEMENT CHAMBER). c) A Catch Pit - Drainage points within a yard or store with connection to containment. If the Catchpit is connected to a receiving store by gravity, its size is not governed. If the waste is pumped, the Catchpit should provide 25mm storage over the contaminated area. A greater figure may be used if the sensitivity of the site is high. d) Multi Chamber Settlement System - Containment used prior to distribution - An overflow to safe storage is permitted unless silage effluent is an ingredient of the waste. Any settlement system taking silage effluent must be certified to last 20 years with no maintenance if below ground. The freeboard limit of 300mm or 750mm does not apply to multi settlement tanks unless they are of earth construction. e) Freeboard - The minimum distance between the top of the store and its contents. There must be provision made for not less than 750mm of freeboard in the case of a tank with walls made of earth and 300mm of freeboard in all other cases. f) Cattle Yards - Not covered by slurry regulations. g) Silage Silo - An impermeable base which includes perimeter drains beyond any walls or silage. The base must be constructed to last for 20 years with maintenance and accept machinery forces which are expected during use. Any walls built must not exceed the base and must comply to load bearings. Impermeability is not covered for any structural support that retains the crop in the reqs. To calculate the loadings on any walls is detailed and complex (BS 5502 Part 22) and is a specialist job. A display sign must be attached to the structure if walls are present explaining their loading capability. h) Silage Effluent Tank - Must be designed to be impermeable and last for twenty years below ground without maintenance. THIS STRUCTURE NEEDS CERTIFICATION. The size is calculated by using the figures shown in the accompanying graph. i) High Rate Irrigation - Systems using large bore pipelines, high flow rates and application rates. These systems are not advisable during winter months unless two months total containment is provided and suitable land for spreading is available. These systems are usually tractor driven. (NB Distribution rates should not exceed 5mm in one hour). j) Low Rate Irrigation - Systems using up to small bore pipeline distributing settled waste at low volumes (generally up to 5m an hour and distributing it evenly at an application rate of below 5mm in any hour depending on ground type. SBN/PL 8.9.1992 SILAGE CLAMP EFFLUENT REQUir^iKNTS (FOR NEW OR IMPROVED STRUCTURES) (NB ADD AN ADDITIONAL 1M3 FOR EACH 150M3 OF SILO CAPACITY IN EXCEOS OF 1500M3 (OR 6.7 LT PER M3 OF SILO) SIZE F CLAMP IN M3 M3 TANK SIZE RAINFALL SECTION INFORMATION Rainfall figures have a large part to play in calculating the type of scheme a unit should install and associated distribution methods. Enclosed in this section are the average rainfall figures for the South West Region- The information produced by the National Rivers Authority's Hydrometric Section can be used to work out probability levels of worst events, more commonly known as "return periods". The National Rivers Authority's Hydrometric Section use additional information such as flood studies to accurately predict return periods. An accurate return period figure can be obtained by the National Rivers Authority Hydrometric Section at Exeter. This information has to be calculated for individual sites so an instant response is not always possible. Different durations and return periods need to be used according to the circumstances. In designing a dirty water settlement tank and pumping system, for example, it may be appropriate to consider: (1) a medium duration rainfall (24 hours) in calculating the total capacity of the tank and (2) a short duration rainfall (1-3 hours) in calculating pumping requi rements. In estimating the capacity required for a slurry storage tank to take four months waste production (as required by the Control of Pollution {Silage, Slurry and Agricultural Fuel Oil) Regulations 1991) a four month duration rainfall estimate should be used. The National Rivers Authority Farm Waste Group have recently been discussing buffer storage capacity in multi settlement chambers (Figure 78). A figure of 25mm rainfall over the total catchment area should be the minimum buffer storage capacity in any multi settlement and distribution system. Information supplied by the applicant on the FPC1 form will enable the pollution staff to calculate a minimum buffer capacity and relate that to the overall proposal. It must be understood that if the site of such a system poses a possible pollution risk due to proximity of a watercourse or a high rainfall area, a higher figure would be used.