Farm Waste Management

Unpolluted river

The collection, storage and handling of wastes from agriculture continues to be a major challenge on many Northern Ireland farms. It is estimated that each year some 20 million cubic metres of farm wastes are produced and require storage. Virtually all of this is disposed of by land spreading.

Agricultural wastes, including silage effluent, slurry and dirty yard water have a very high pollution potential. Silage effluent is most polluting at about 200 times the pollution potential of raw domestic sewage. When agricultural wastes get into waterways the consequences for river life can be devastating. In serious pollution cases all river life can be killed for considerable distances downstream. Responsible farm waste management is essential to ensure pollution is prevented.

The pollution of water is an offence and under the Water (Northern Ireland) Order 1999 a maximum fine of £20,000 can be imposed on offenders. According to the Northern Ireland Environment Agency (NIEA) approximately one third of all substantiated pollution incidents each year are attributed to agriculture. For more information on water pollution incidents and water quality see the NIEA www.ni-environment.gov.uk

website.

Types of Water Pollution

There are two main types of water pollution from agriculture – point source and diffuse

Point source pollution

Pollution of a waterway from a particular source such as a tank, building or field is referred to as point source pollution. This can result when slurry, silage effluent or uncollected dirty water reaches a waterway. It can also be caused by fuel oil, pesticides or sheep dip which can poison or damage river life or make groundwater unfit for use.

When farm wastes get into a waterway, they are broken down by microorganisms. This process uses oxygen needed by river life, including plants and fish, to survive. Biochemical oxygen demand (BOD) is a measure of the amount of oxygen needed by these microorganisms to break down the organic material. BOD is therefore a measure of the polluting strength of organic wastes. Farm wastes have a high BOD. The higher the BOD the more polluting the waste. In serious pollution cases, all river life can be killed for considerable distances downstream.

Typical BOD values for farm wastes.

Waste Biochemical Oxygen Demand (mg/litre of oxygen)

Whole milk 100,000

Silage effluent 65,000

Pig slurry 25,000

Cattle slurry 17,000

Dirty yard water 1,500

Raw vegetable washings 500 – 3,000

Dilute dairy & parlour washings 1,000 – 2,000

Raw domestic sewage 300

Diffuse Pollution

Diffuse pollution cannot be attributed to a single event or action and is generally caused by nitrates, phosphates and pesticides.

A significant diffuse pollution problem in Northern Ireland has resulted from a leakage of phosphorus from soils that are oversupplied. In many cases, this has caused surface waters to become enriched with nutrients leading to enhanced growth of algae and aquatic plants (eutrophication). (See picture below). This can have many undesirable effects, including posing a health risk to both animals and humans.

surface waters enriched with nutrients leading to enhanced growth of algae

Information on eutrophication research and in particular the impact of agriculture on phosphorus loadings to Lough Neagh can be found on the Agri-food and Biosciences Institute[external site] website.

Information on eutrophication research and in particular the impact of agriculture on phosphorus loadings to Lough Neagh can be found on the Agri-food and Biosciences Institute

website.

Farm Waste Management (FWM) and the role of Countryside Management Unit (CMU)

Provide Advice
One of the main roles of CMU is to provide advice to farmers on all aspects of farm waste management and pollution control. All applicants to Department of Agriculture and Rural Development agri-environment schemes receive a farm waste management advisory visit as part of their application to the scheme. CMU also offer farmers an advisory visit after they have had a pollution incident substantiated by the DOE.
Produce and promote the Code of Good Agricultural Practice for the prevention of pollution of water.
The Code contains practical management advice on how farm wastes such as silage effluent, slurry and manure can be collected, stored and spread with minimum risk to the environment. Guidance on how to prevent pollution from pesticides, sheep dip and fuel oil is also included. The Code also contains useful worksheets on how to calculate slurry storage capacity on the farm.
If you are in receipt of Less Favoured Areas Compensatory Allowances (LFACA) payments, participating in an agri-environment scheme or in the Livestock Meat Comission (LMC) Farm Quality Assurance Scheme for Beef or Lamb you must retain copies of the Codes.
Develop Training Courses
CMU is responsible for the development of a range of agri-environment training courses for farmers including dealing with farm wastes and nutrient management planning. These courses are delivered by the College of Agriculture, Food and Rural Enterprise.

For more information on agricultural waste, see www.netregs.gov.uk/farmwaste