Good management of organic waste enables food and drink producers and hospitality businesses to reduce the disposal of organic waste to landfill. In turn this helps your business to meet legal, economic, stakeholder and media pressures.

Organic waste legal pressures

Managing your organic waste effectively will help you comply with legal requirements, such as regulations on animal by-products and landfill.

The Animal By-Products Regulations aim to control the risk of disease to both animals and the public. Animal by-products are allocated to one of three categories according to the risk they pose, and this category determines the waste management options permitted. Catering waste, former foodstuffs, and raw meat and raw fish from food manufacturers and food retailers are usually Category 3, the lowest risk.

Controls on waste disposed of to landfill are becoming increasingly tighter. Certain wastes are now banned, including liquid wastes. You or your waste contractor must also treat all waste in some way before it is sent to landfill as part of your duty of care for business waste.

Organic waste economic pressures

Reducing the amount of organic waste that you send to landfill will reduce your costs because food waste attracts the higher rate of landfill tax. Disposing of mixed waste to landfill sites is becoming increasingly less economically viable because of:

• annual increases in the landfill tax
• higher charges by operators to recoup the costs associated with stricter rules governing landfill design and operation
• the requirement to treat waste before consigning it to landfill

Organic waste stakeholder pressures

The environment is an increasingly important part of the corporate and societal agenda. Environmental performance and responsible behaviour in the community are increasingly important factors in winning and keeping new customers. Businesses are increasingly expected by their stakeholders - customers, investors, suppliers, media, etc - to demonstrate a commitment to minimising and managing waste.

Although organic waste management or treatment is important, it is not the most efficient use of resources for food and drink producers and hospitality businesses. The best approach is to avoid creating waste in the first place, as this will save you money.

If you can't avoid it, look at how you can reuse waste materials.

Food business waste reduction tips

To help prevent waste, take the following steps:

• Form a waste reduction team to lead initiatives to reduce and eliminate waste.
• Obtain support - the help and commitment of everyone in your business, including senior management, is essential for effective waste reduction.
• Measure - make an inventory of your materials and processes to identify ways to minimise waste.
• Prioritise - target major sources of waste first, as this should yield early successes and savings. Look at the largest quantities going to waste and at the highest net costs.
• Welcome ideas - talk to the key people involved in handling and dealing with each type of waste, and be prepared to challenge and question existing practices. You could ask why there is so much waste, whether anyone has looked at this as a problem before, whether there are processes that could be updated and what you think could be done to cut waste.

Putting waste reduction ideas into action

Your waste reduction team should be able to come up with a list of actions to reduce or eliminate waste. If necessary, hold an informal brainstorming session to get ideas. Estimate the costs and savings of different initiatives as accurately as possible.

You should also devise an action plan - for the short, medium and long term - with dates, costs and targets.

To be successful, you need to:

• be systematic - some changes can be introduced almost overnight, while others will take longer and need careful planning
• measure and quantify cost savings, payback periods and quantities of waste reduced
• communicate - this will help to motivate staff and keep the board supportive

Once you have implemented measures for reducing and reusing organic waste, the next step is to recycle organic waste that is left. This usually requires you to separate different types of waste.

Organic waste is not always welcomed by waste management businesses because:

• wet wastes such as food wastes are liable to decay and can cause smells
• wet wastes present a high pollution risk, particularly to water
• natural degradation can make landfill unstable
• uncontrolled production of landfill gas is hazardous and damaging to the environment
• it can be costly to transport

However, there are a number of relatively straightforward methods to treat organic material for recycling. On-site treatment of organic waste can substantially and quickly reduce the amount of waste material and the cost of disposal. If treated fully and appropriately organic waste can become a valuable resource as compost, energy or fertiliser.

However, if your business processes food or is involved in catering you cannot risk creating problems such as microbial hazards or odour. On-site solutions must, therefore, be both safe and 'biosecure' - preventing biological contamination and the spread of infectious organisms.

Regulatory issues with organic waste

Various environmental regulations determine what organic waste you can recycle. The Animal By-Products Regulations are key and you should check how these apply to you. The rules also vary depending on whether you are:

• processing your own waste
• processing and exporting products
• getting someone else to process your waste for you

Since organic waste is highly regulated, it is important to understand whether:

• your treatment choices comply with current legislation
• anyone to whom you transfer waste is using appropriate technology

There are significant costs associated with any method of disposal as well as substantial penalties for being ill-informed, so there can be real cost benefits in modern treatment, recycling and waste reduction.

Composting breaks down organic material to produce safe, stable reusable material - compost. The temperatures achieved during composting destroy any harmful pathogens present. You can compost most organic waste, but the method depends on the nature and amount of the waste and the level of regulation that applies.

Materials such as garden waste - so-called 'green waste' including grass cuttings, prunings and leaves - from your grounds can be composted easily outdoors. Material liable to cause smells may need to be put in a box or tank to minimise odour and prevent leaks of any liquids that may be produced.

The most appropriate composting method is likely to depend on how much waste you produce.

Composting small amounts of organic waste

Relatively small amounts of waste, eg leftover food from a small restaurant, can be treated in a 'back-door' composter similar to home compost bins. Such composting is lightly regulated providing any product is used only on site, eg for mulching flower beds around a hotel or kitchen. You should:

• ensure the composter is vermin-proof
• blend material likely to cause smells with garden wastes and other materials (eg cardboard) to reduce the risk
• aerate simple compost boxes by turning the contents (eg using a garden fork) regularly

You can also use this kind of composting at larger sites. You should establish a contained system to make it easier for staff to use and to keep the process clean.

Composting large amounts of organic waste

For larger quantities of green waste, you can generally carry out composting outdoors using relatively simple equipment such as tractors/loaders or tractor-drawn compost turners to aerate windrows. You may require additional equipment such as shredders.

These relatively simple operations tend to be labour-intensive and have a high energy cost per tonne. They may also result in poor product quality. Larger operations using specialist equipment are more likely to be successful but require investment in dedicated machinery. When deciding which machinery to use, capital cost may be less important than long-term operating and servicing costs.

Although large-scale composting is not appropriate for most businesses, there may be opportunities to form a partnership with neighbours. For example, a farm may be willing to compost rejects from a local vegetable processing plant.

The compost that you produce is likely to still be waste until it has been spread on land for beneficial purposes.

If you choose not to go down the quality protocol route the compost must be spread under either a waste exemption or a land-spreading permit. Most businesses will qualify for a waste exemption. In the unlikely event that you don't you will need to obtain a permit.

Wastes covered by the Animal By-products Regulations

Various requirements apply if material to be composted is covered under the Animal By-Products Regulations. Complying with the regulations is a requirement for any commercial waste food processing.

Food and drink producers and hospitality businesses could consider anaerobic digestion of their organic waste. This involves the treatment of organic material in the absence of oxygen (air). The digestion process involves degrading material with microbes but uses a different group of naturally occurring micro-organisms to composting. This process generally has three outputs:

• Digestate - a wetted, solid material that usually requires maturing or composting before it can be used, eg applied to soil.
• Liquid - may be rich in nutrients and can be used as a fertiliser.
• Biogas - can be used to generate electricity or burnt as a renewable fuel. It generally contains around 60 per cent methane, with carbon dioxide the other main component.

An important difference between composting and anaerobic digestion is that biogas is released during the fermentation process. Biogas is suitable for use in some gas engines and is often used in combined heat and power units to generate electricity and heat.

If you intend to set up your own anaerobic digestion system, check whether you need authorisation from the Northern Ireland Environment Agency. If you use a system operated by another organisation, check they are authorised to operate it.

The outputs from anaerobic digestion are still waste unless they have been produced on farms using certain waste types. They are therefore still subject to waste regulation and their use must be registered under a waste exemption or an environmental permit.

To make sure the use of anaerobic digestate isn't regulated by waste legislation you should meet the requirements of the quality protocol for anaerobic digestate.

Digester system design

There are various digester designs, each suited to different circumstances. The design of an anaerobic digestion system provides the optimum conditions in which micro-organisms can flourish and degrade the waste. This requires:

• a balanced and predictable internal environment
• control of the rate of input and output and process conditions such as temperature and acidity

Wet digestion of organic waste

This type of digester has technology that is proven, robust and relatively simple to operate. The digestion of dense materials such as food waste and similar solids/semi-solids requires their dilution in a large volume of water so any solid output will need to be dewatered. Liquid outputs can be recycled within the process to reintroduce the bacteria and reduce water use.

Dry digestion of organic waste

High solids processes are not dry. The waste is processed at 20 to 40 per cent moisture, generally as a pumpable mass blended to the correct consistency using specialist equipment and injected into the digester. Virtually no liquid make-up is required and the liquid output is modest. This liquid tends to have a relatively high nutrient content and is a useful fertiliser.

Dry digesters can be horizontal and may have a void above the digestion mass, which can act as a buffer for low pressure biogas production and storage. This removes the need for additional gas management and separate storage vessels.

Digester biosecurity

Traditional wastewater anaerobic digestion systems operate at a relatively low temperature of around 35°C. At these temperatures the mass is transformed substantially, coupled with biogas release, but harmful micro-organisms and parasites may not be eliminated. Organic wastes must be subjected to controlled pasteurisation involving temperatures of 55-70°C.

There are various other physical and chemical methods that food and drink producers and hospitality businesses can use to treat organic waste. However, these tend to be large-scale solutions, so smaller businesses are likely to need other organisations as partners or contractors.

Rendering

Rendering involves the partial recovery of materials from animal by-products (including former foodstuffs) by crushing and grinding, followed by heat treatment to reduce the moisture content and kill micro-organisms. Renderers process most animal by-products from the meat production chain to produce tallow and protein meal. Tallow is used in industries as diverse as paint manufacture and tyre production, as well as for fuel.

Autoclaving

Autoclaving is a conventional combination of heat treatment under pressure and has been used for many years as a sterilisation process. Heat is applied to material either directly as steam or by heating the vessel to release steam from the moisture content of the material being treated. This increases the pressure within the closed vessel. Organic waste such as food and vegetable residues, paper and cardboard etc will result in an organic 'wool' or fibre when treated in an autoclave.

Hydrolysis

Hydrolysis is a process in which chemical bonds are broken by the 'insertion' of water between the atoms in the chemical bond. This destroys the protein/amino acid framework of organic waste and is particularly suited to high risk wastes, such as high level animal by-product wastes.

Microwave treatment

Microwave treatment of organic waste tends to be small scale and is predominantly used to sterilise high risk material. Microwave systems are either batch or through-flow, and may be used alone or in combination with steam injection systems, which increase the efficiency of the microwave process and help to raise its temperature to pasteurisation levels.

Food and drink producers and hospitality businesses can consider various other treatment systems involving the use of heat. These all require specialist facilities.

Incineration

Incineration does not produce usable by-products, although the energy can be used to generate electricity. Many organic wastes have a high moisture content and may require drying before combustion. Incinerator plants that burn only animal carcasses or parts of carcasses must be approved under the Animal By-Products Regulations, but are exempt from more onerous waste incineration controls. However, plants that burn other animal by-products must be permitted or licensed by the Northern Ireland Environment Agency.

Pyrolysis

Pyrolysis is the thermal destruction or decomposition of material occurring in the absence of oxygen. In fast pyrolysis, the waste degenerates to give vapours, aerosols and some charcoal. After cooling and condensation, a dark brown liquid is formed which has a heating value about half that of conventional fuel oil. Virtually any form of organic waste can be considered for fast pyrolysis.

Gasification

Gasification is closely linked to pyrolysis. When waste material is heated with no more than around one-third of the amount of oxygen needed for efficient combustion, it gasifies to a mixture of carbon monoxide and hydrogen (synthesis gas or syngas) potentially with carbon dioxide and methane. The amount of oxygen and other conditions determine whether the biomass gasifies. Biomass and biowaste gasification can improve the efficiency of large-scale biomass power facilities and specialised facilities.

Plasma gasification

Plasma gasification is where waste is fed to a reactor where it is exposed to an electrically-generated plasma. The waste is heated to over 2,000 degrees Celsius, causing organic compounds to break down to form molecules such as hydrogen, carbon monoxide, carbon dioxide, water vapour and methane. The gas from the reactor is suitable as fuel for a gas-fired generation unit or can be used as a feedstock for chemical processes such as methanol production.

Good management of organic waste enables food and drink producers and hospitality businesses to reduce the disposal of organic waste to landfill. In turn this helps your business to meet legal, economic, stakeholder and media pressures.

Organic waste legal pressures

Managing your organic waste effectively will help you comply with legal requirements, such as regulations on animal by-products and landfill.

The Animal By-Products Regulations aim to control the risk of disease to both animals and the public. Animal by-products are allocated to one of three categories according to the risk they pose, and this category determines the waste management options permitted. Catering waste, former foodstuffs, and raw meat and raw fish from food manufacturers and food retailers are usually Category 3, the lowest risk.

Controls on waste disposed of to landfill are becoming increasingly tighter. Certain wastes are now banned, including liquid wastes. You or your waste contractor must also treat all waste in some way before it is sent to landfill as part of your duty of care for business waste.

Organic waste economic pressures

Reducing the amount of organic waste that you send to landfill will reduce your costs because food waste attracts the higher rate of landfill tax. Disposing of mixed waste to landfill sites is becoming increasingly less economically viable because of:

• annual increases in the landfill tax
• higher charges by operators to recoup the costs associated with stricter rules governing landfill design and operation
• the requirement to treat waste before consigning it to landfill

Organic waste stakeholder pressures

The environment is an increasingly important part of the corporate and societal agenda. Environmental performance and responsible behaviour in the community are increasingly important factors in winning and keeping new customers. Businesses are increasingly expected by their stakeholders - customers, investors, suppliers, media, etc - to demonstrate a commitment to minimising and managing waste.

Although organic waste management or treatment is important, it is not the most efficient use of resources for food and drink producers and hospitality businesses. The best approach is to avoid creating waste in the first place, as this will save you money.

If you can't avoid it, look at how you can reuse waste materials.

Food business waste reduction tips

To help prevent waste, take the following steps:

• Form a waste reduction team to lead initiatives to reduce and eliminate waste.
• Obtain support - the help and commitment of everyone in your business, including senior management, is essential for effective waste reduction.
• Measure - make an inventory of your materials and processes to identify ways to minimise waste.
• Prioritise - target major sources of waste first, as this should yield early successes and savings. Look at the largest quantities going to waste and at the highest net costs.
• Welcome ideas - talk to the key people involved in handling and dealing with each type of waste, and be prepared to challenge and question existing practices. You could ask why there is so much waste, whether anyone has looked at this as a problem before, whether there are processes that could be updated and what you think could be done to cut waste.

Putting waste reduction ideas into action

Your waste reduction team should be able to come up with a list of actions to reduce or eliminate waste. If necessary, hold an informal brainstorming session to get ideas. Estimate the costs and savings of different initiatives as accurately as possible.

You should also devise an action plan - for the short, medium and long term - with dates, costs and targets.

To be successful, you need to:

• be systematic - some changes can be introduced almost overnight, while others will take longer and need careful planning
• measure and quantify cost savings, payback periods and quantities of waste reduced
• communicate - this will help to motivate staff and keep the board supportive

Once you have implemented measures for reducing and reusing organic waste, the next step is to recycle organic waste that is left. This usually requires you to separate different types of waste.

Organic waste is not always welcomed by waste management businesses because:

• wet wastes such as food wastes are liable to decay and can cause smells
• wet wastes present a high pollution risk, particularly to water
• natural degradation can make landfill unstable
• uncontrolled production of landfill gas is hazardous and damaging to the environment
• it can be costly to transport

However, there are a number of relatively straightforward methods to treat organic material for recycling. On-site treatment of organic waste can substantially and quickly reduce the amount of waste material and the cost of disposal. If treated fully and appropriately organic waste can become a valuable resource as compost, energy or fertiliser.

However, if your business processes food or is involved in catering you cannot risk creating problems such as microbial hazards or odour. On-site solutions must, therefore, be both safe and 'biosecure' - preventing biological contamination and the spread of infectious organisms.

Regulatory issues with organic waste

Various environmental regulations determine what organic waste you can recycle. The Animal By-Products Regulations are key and you should check how these apply to you. The rules also vary depending on whether you are:

• processing your own waste
• processing and exporting products
• getting someone else to process your waste for you

Since organic waste is highly regulated, it is important to understand whether:

• your treatment choices comply with current legislation
• anyone to whom you transfer waste is using appropriate technology

There are significant costs associated with any method of disposal as well as substantial penalties for being ill-informed, so there can be real cost benefits in modern treatment, recycling and waste reduction.

Composting breaks down organic material to produce safe, stable reusable material - compost. The temperatures achieved during composting destroy any harmful pathogens present. You can compost most organic waste, but the method depends on the nature and amount of the waste and the level of regulation that applies.

Materials such as garden waste - so-called 'green waste' including grass cuttings, prunings and leaves - from your grounds can be composted easily outdoors. Material liable to cause smells may need to be put in a box or tank to minimise odour and prevent leaks of any liquids that may be produced.

The most appropriate composting method is likely to depend on how much waste you produce.

Composting small amounts of organic waste

Relatively small amounts of waste, eg leftover food from a small restaurant, can be treated in a 'back-door' composter similar to home compost bins. Such composting is lightly regulated providing any product is used only on site, eg for mulching flower beds around a hotel or kitchen. You should:

• ensure the composter is vermin-proof
• blend material likely to cause smells with garden wastes and other materials (eg cardboard) to reduce the risk
• aerate simple compost boxes by turning the contents (eg using a garden fork) regularly

You can also use this kind of composting at larger sites. You should establish a contained system to make it easier for staff to use and to keep the process clean.

Composting large amounts of organic waste

For larger quantities of green waste, you can generally carry out composting outdoors using relatively simple equipment such as tractors/loaders or tractor-drawn compost turners to aerate windrows. You may require additional equipment such as shredders.

These relatively simple operations tend to be labour-intensive and have a high energy cost per tonne. They may also result in poor product quality. Larger operations using specialist equipment are more likely to be successful but require investment in dedicated machinery. When deciding which machinery to use, capital cost may be less important than long-term operating and servicing costs.

Although large-scale composting is not appropriate for most businesses, there may be opportunities to form a partnership with neighbours. For example, a farm may be willing to compost rejects from a local vegetable processing plant.

The compost that you produce is likely to still be waste until it has been spread on land for beneficial purposes.

If you choose not to go down the quality protocol route the compost must be spread under either a waste exemption or a land-spreading permit. Most businesses will qualify for a waste exemption. In the unlikely event that you don't you will need to obtain a permit.

Wastes covered by the Animal By-products Regulations

Various requirements apply if material to be composted is covered under the Animal By-Products Regulations. Complying with the regulations is a requirement for any commercial waste food processing.

Food and drink producers and hospitality businesses could consider anaerobic digestion of their organic waste. This involves the treatment of organic material in the absence of oxygen (air). The digestion process involves degrading material with microbes but uses a different group of naturally occurring micro-organisms to composting. This process generally has three outputs:

• Digestate - a wetted, solid material that usually requires maturing or composting before it can be used, eg applied to soil.
• Liquid - may be rich in nutrients and can be used as a fertiliser.
• Biogas - can be used to generate electricity or burnt as a renewable fuel. It generally contains around 60 per cent methane, with carbon dioxide the other main component.

An important difference between composting and anaerobic digestion is that biogas is released during the fermentation process. Biogas is suitable for use in some gas engines and is often used in combined heat and power units to generate electricity and heat.

If you intend to set up your own anaerobic digestion system, check whether you need authorisation from the Northern Ireland Environment Agency. If you use a system operated by another organisation, check they are authorised to operate it.

The outputs from anaerobic digestion are still waste unless they have been produced on farms using certain waste types. They are therefore still subject to waste regulation and their use must be registered under a waste exemption or an environmental permit.

To make sure the use of anaerobic digestate isn't regulated by waste legislation you should meet the requirements of the quality protocol for anaerobic digestate.

Digester system design

There are various digester designs, each suited to different circumstances. The design of an anaerobic digestion system provides the optimum conditions in which micro-organisms can flourish and degrade the waste. This requires:

• a balanced and predictable internal environment
• control of the rate of input and output and process conditions such as temperature and acidity

Wet digestion of organic waste

This type of digester has technology that is proven, robust and relatively simple to operate. The digestion of dense materials such as food waste and similar solids/semi-solids requires their dilution in a large volume of water so any solid output will need to be dewatered. Liquid outputs can be recycled within the process to reintroduce the bacteria and reduce water use.

Dry digestion of organic waste

High solids processes are not dry. The waste is processed at 20 to 40 per cent moisture, generally as a pumpable mass blended to the correct consistency using specialist equipment and injected into the digester. Virtually no liquid make-up is required and the liquid output is modest. This liquid tends to have a relatively high nutrient content and is a useful fertiliser.

Dry digesters can be horizontal and may have a void above the digestion mass, which can act as a buffer for low pressure biogas production and storage. This removes the need for additional gas management and separate storage vessels.

Digester biosecurity

Traditional wastewater anaerobic digestion systems operate at a relatively low temperature of around 35°C. At these temperatures the mass is transformed substantially, coupled with biogas release, but harmful micro-organisms and parasites may not be eliminated. Organic wastes must be subjected to controlled pasteurisation involving temperatures of 55-70°C.

There are various other physical and chemical methods that food and drink producers and hospitality businesses can use to treat organic waste. However, these tend to be large-scale solutions, so smaller businesses are likely to need other organisations as partners or contractors.

Rendering

Rendering involves the partial recovery of materials from animal by-products (including former foodstuffs) by crushing and grinding, followed by heat treatment to reduce the moisture content and kill micro-organisms. Renderers process most animal by-products from the meat production chain to produce tallow and protein meal. Tallow is used in industries as diverse as paint manufacture and tyre production, as well as for fuel.

Autoclaving

Autoclaving is a conventional combination of heat treatment under pressure and has been used for many years as a sterilisation process. Heat is applied to material either directly as steam or by heating the vessel to release steam from the moisture content of the material being treated. This increases the pressure within the closed vessel. Organic waste such as food and vegetable residues, paper and cardboard etc will result in an organic 'wool' or fibre when treated in an autoclave.

Hydrolysis

Hydrolysis is a process in which chemical bonds are broken by the 'insertion' of water between the atoms in the chemical bond. This destroys the protein/amino acid framework of organic waste and is particularly suited to high risk wastes, such as high level animal by-product wastes.

Microwave treatment

Microwave treatment of organic waste tends to be small scale and is predominantly used to sterilise high risk material. Microwave systems are either batch or through-flow, and may be used alone or in combination with steam injection systems, which increase the efficiency of the microwave process and help to raise its temperature to pasteurisation levels.

Food and drink producers and hospitality businesses can consider various other treatment systems involving the use of heat. These all require specialist facilities.

Incineration

Incineration does not produce usable by-products, although the energy can be used to generate electricity. Many organic wastes have a high moisture content and may require drying before combustion. Incinerator plants that burn only animal carcasses or parts of carcasses must be approved under the Animal By-Products Regulations, but are exempt from more onerous waste incineration controls. However, plants that burn other animal by-products must be permitted or licensed by the Northern Ireland Environment Agency.

Pyrolysis

Pyrolysis is the thermal destruction or decomposition of material occurring in the absence of oxygen. In fast pyrolysis, the waste degenerates to give vapours, aerosols and some charcoal. After cooling and condensation, a dark brown liquid is formed which has a heating value about half that of conventional fuel oil. Virtually any form of organic waste can be considered for fast pyrolysis.

Gasification

Gasification is closely linked to pyrolysis. When waste material is heated with no more than around one-third of the amount of oxygen needed for efficient combustion, it gasifies to a mixture of carbon monoxide and hydrogen (synthesis gas or syngas) potentially with carbon dioxide and methane. The amount of oxygen and other conditions determine whether the biomass gasifies. Biomass and biowaste gasification can improve the efficiency of large-scale biomass power facilities and specialised facilities.

Plasma gasification

Plasma gasification is where waste is fed to a reactor where it is exposed to an electrically-generated plasma. The waste is heated to over 2,000 degrees Celsius, causing organic compounds to break down to form molecules such as hydrogen, carbon monoxide, carbon dioxide, water vapour and methane. The gas from the reactor is suitable as fuel for a gas-fired generation unit or can be used as a feedstock for chemical processes such as methanol production.

Good management of organic waste enables food and drink producers and hospitality businesses to reduce the disposal of organic waste to landfill. In turn this helps your business to meet legal, economic, stakeholder and media pressures.

Organic waste legal pressures

Managing your organic waste effectively will help you comply with legal requirements, such as regulations on animal by-products and landfill.

The Animal By-Products Regulations aim to control the risk of disease to both animals and the public. Animal by-products are allocated to one of three categories according to the risk they pose, and this category determines the waste management options permitted. Catering waste, former foodstuffs, and raw meat and raw fish from food manufacturers and food retailers are usually Category 3, the lowest risk.

Controls on waste disposed of to landfill are becoming increasingly tighter. Certain wastes are now banned, including liquid wastes. You or your waste contractor must also treat all waste in some way before it is sent to landfill as part of your duty of care for business waste.

Organic waste economic pressures

Reducing the amount of organic waste that you send to landfill will reduce your costs because food waste attracts the higher rate of landfill tax. Disposing of mixed waste to landfill sites is becoming increasingly less economically viable because of:

• annual increases in the landfill tax
• higher charges by operators to recoup the costs associated with stricter rules governing landfill design and operation
• the requirement to treat waste before consigning it to landfill

Organic waste stakeholder pressures

The environment is an increasingly important part of the corporate and societal agenda. Environmental performance and responsible behaviour in the community are increasingly important factors in winning and keeping new customers. Businesses are increasingly expected by their stakeholders - customers, investors, suppliers, media, etc - to demonstrate a commitment to minimising and managing waste.

Although organic waste management or treatment is important, it is not the most efficient use of resources for food and drink producers and hospitality businesses. The best approach is to avoid creating waste in the first place, as this will save you money.

If you can't avoid it, look at how you can reuse waste materials.

Food business waste reduction tips

To help prevent waste, take the following steps:

• Form a waste reduction team to lead initiatives to reduce and eliminate waste.
• Obtain support - the help and commitment of everyone in your business, including senior management, is essential for effective waste reduction.
• Measure - make an inventory of your materials and processes to identify ways to minimise waste.
• Prioritise - target major sources of waste first, as this should yield early successes and savings. Look at the largest quantities going to waste and at the highest net costs.
• Welcome ideas - talk to the key people involved in handling and dealing with each type of waste, and be prepared to challenge and question existing practices. You could ask why there is so much waste, whether anyone has looked at this as a problem before, whether there are processes that could be updated and what you think could be done to cut waste.

Putting waste reduction ideas into action

Your waste reduction team should be able to come up with a list of actions to reduce or eliminate waste. If necessary, hold an informal brainstorming session to get ideas. Estimate the costs and savings of different initiatives as accurately as possible.

You should also devise an action plan - for the short, medium and long term - with dates, costs and targets.

To be successful, you need to:

• be systematic - some changes can be introduced almost overnight, while others will take longer and need careful planning
• measure and quantify cost savings, payback periods and quantities of waste reduced
• communicate - this will help to motivate staff and keep the board supportive

Once you have implemented measures for reducing and reusing organic waste, the next step is to recycle organic waste that is left. This usually requires you to separate different types of waste.

Organic waste is not always welcomed by waste management businesses because:

• wet wastes such as food wastes are liable to decay and can cause smells
• wet wastes present a high pollution risk, particularly to water
• natural degradation can make landfill unstable
• uncontrolled production of landfill gas is hazardous and damaging to the environment
• it can be costly to transport

However, there are a number of relatively straightforward methods to treat organic material for recycling. On-site treatment of organic waste can substantially and quickly reduce the amount of waste material and the cost of disposal. If treated fully and appropriately organic waste can become a valuable resource as compost, energy or fertiliser.

However, if your business processes food or is involved in catering you cannot risk creating problems such as microbial hazards or odour. On-site solutions must, therefore, be both safe and 'biosecure' - preventing biological contamination and the spread of infectious organisms.

Regulatory issues with organic waste

Various environmental regulations determine what organic waste you can recycle. The Animal By-Products Regulations are key and you should check how these apply to you. The rules also vary depending on whether you are:

• processing your own waste
• processing and exporting products
• getting someone else to process your waste for you

Since organic waste is highly regulated, it is important to understand whether:

• your treatment choices comply with current legislation
• anyone to whom you transfer waste is using appropriate technology

There are significant costs associated with any method of disposal as well as substantial penalties for being ill-informed, so there can be real cost benefits in modern treatment, recycling and waste reduction.

Composting breaks down organic material to produce safe, stable reusable material - compost. The temperatures achieved during composting destroy any harmful pathogens present. You can compost most organic waste, but the method depends on the nature and amount of the waste and the level of regulation that applies.

Materials such as garden waste - so-called 'green waste' including grass cuttings, prunings and leaves - from your grounds can be composted easily outdoors. Material liable to cause smells may need to be put in a box or tank to minimise odour and prevent leaks of any liquids that may be produced.

The most appropriate composting method is likely to depend on how much waste you produce.

Composting small amounts of organic waste

Relatively small amounts of waste, eg leftover food from a small restaurant, can be treated in a 'back-door' composter similar to home compost bins. Such composting is lightly regulated providing any product is used only on site, eg for mulching flower beds around a hotel or kitchen. You should:

• ensure the composter is vermin-proof
• blend material likely to cause smells with garden wastes and other materials (eg cardboard) to reduce the risk
• aerate simple compost boxes by turning the contents (eg using a garden fork) regularly

You can also use this kind of composting at larger sites. You should establish a contained system to make it easier for staff to use and to keep the process clean.

Composting large amounts of organic waste

For larger quantities of green waste, you can generally carry out composting outdoors using relatively simple equipment such as tractors/loaders or tractor-drawn compost turners to aerate windrows. You may require additional equipment such as shredders.

These relatively simple operations tend to be labour-intensive and have a high energy cost per tonne. They may also result in poor product quality. Larger operations using specialist equipment are more likely to be successful but require investment in dedicated machinery. When deciding which machinery to use, capital cost may be less important than long-term operating and servicing costs.

Although large-scale composting is not appropriate for most businesses, there may be opportunities to form a partnership with neighbours. For example, a farm may be willing to compost rejects from a local vegetable processing plant.

The compost that you produce is likely to still be waste until it has been spread on land for beneficial purposes.

If you choose not to go down the quality protocol route the compost must be spread under either a waste exemption or a land-spreading permit. Most businesses will qualify for a waste exemption. In the unlikely event that you don't you will need to obtain a permit.

Wastes covered by the Animal By-products Regulations

Various requirements apply if material to be composted is covered under the Animal By-Products Regulations. Complying with the regulations is a requirement for any commercial waste food processing.

Food and drink producers and hospitality businesses could consider anaerobic digestion of their organic waste. This involves the treatment of organic material in the absence of oxygen (air). The digestion process involves degrading material with microbes but uses a different group of naturally occurring micro-organisms to composting. This process generally has three outputs:

• Digestate - a wetted, solid material that usually requires maturing or composting before it can be used, eg applied to soil.
• Liquid - may be rich in nutrients and can be used as a fertiliser.
• Biogas - can be used to generate electricity or burnt as a renewable fuel. It generally contains around 60 per cent methane, with carbon dioxide the other main component.

An important difference between composting and anaerobic digestion is that biogas is released during the fermentation process. Biogas is suitable for use in some gas engines and is often used in combined heat and power units to generate electricity and heat.

If you intend to set up your own anaerobic digestion system, check whether you need authorisation from the Northern Ireland Environment Agency. If you use a system operated by another organisation, check they are authorised to operate it.

The outputs from anaerobic digestion are still waste unless they have been produced on farms using certain waste types. They are therefore still subject to waste regulation and their use must be registered under a waste exemption or an environmental permit.

To make sure the use of anaerobic digestate isn't regulated by waste legislation you should meet the requirements of the quality protocol for anaerobic digestate.

Digester system design

There are various digester designs, each suited to different circumstances. The design of an anaerobic digestion system provides the optimum conditions in which micro-organisms can flourish and degrade the waste. This requires:

• a balanced and predictable internal environment
• control of the rate of input and output and process conditions such as temperature and acidity

Wet digestion of organic waste

This type of digester has technology that is proven, robust and relatively simple to operate. The digestion of dense materials such as food waste and similar solids/semi-solids requires their dilution in a large volume of water so any solid output will need to be dewatered. Liquid outputs can be recycled within the process to reintroduce the bacteria and reduce water use.

Dry digestion of organic waste

High solids processes are not dry. The waste is processed at 20 to 40 per cent moisture, generally as a pumpable mass blended to the correct consistency using specialist equipment and injected into the digester. Virtually no liquid make-up is required and the liquid output is modest. This liquid tends to have a relatively high nutrient content and is a useful fertiliser.

Dry digesters can be horizontal and may have a void above the digestion mass, which can act as a buffer for low pressure biogas production and storage. This removes the need for additional gas management and separate storage vessels.

Digester biosecurity

Traditional wastewater anaerobic digestion systems operate at a relatively low temperature of around 35°C. At these temperatures the mass is transformed substantially, coupled with biogas release, but harmful micro-organisms and parasites may not be eliminated. Organic wastes must be subjected to controlled pasteurisation involving temperatures of 55-70°C.

There are various other physical and chemical methods that food and drink producers and hospitality businesses can use to treat organic waste. However, these tend to be large-scale solutions, so smaller businesses are likely to need other organisations as partners or contractors.

Rendering

Rendering involves the partial recovery of materials from animal by-products (including former foodstuffs) by crushing and grinding, followed by heat treatment to reduce the moisture content and kill micro-organisms. Renderers process most animal by-products from the meat production chain to produce tallow and protein meal. Tallow is used in industries as diverse as paint manufacture and tyre production, as well as for fuel.

Autoclaving

Autoclaving is a conventional combination of heat treatment under pressure and has been used for many years as a sterilisation process. Heat is applied to material either directly as steam or by heating the vessel to release steam from the moisture content of the material being treated. This increases the pressure within the closed vessel. Organic waste such as food and vegetable residues, paper and cardboard etc will result in an organic 'wool' or fibre when treated in an autoclave.

Hydrolysis

Hydrolysis is a process in which chemical bonds are broken by the 'insertion' of water between the atoms in the chemical bond. This destroys the protein/amino acid framework of organic waste and is particularly suited to high risk wastes, such as high level animal by-product wastes.

Microwave treatment

Microwave treatment of organic waste tends to be small scale and is predominantly used to sterilise high risk material. Microwave systems are either batch or through-flow, and may be used alone or in combination with steam injection systems, which increase the efficiency of the microwave process and help to raise its temperature to pasteurisation levels.

Food and drink producers and hospitality businesses can consider various other treatment systems involving the use of heat. These all require specialist facilities.

Incineration

Incineration does not produce usable by-products, although the energy can be used to generate electricity. Many organic wastes have a high moisture content and may require drying before combustion. Incinerator plants that burn only animal carcasses or parts of carcasses must be approved under the Animal By-Products Regulations, but are exempt from more onerous waste incineration controls. However, plants that burn other animal by-products must be permitted or licensed by the Northern Ireland Environment Agency.

Pyrolysis

Pyrolysis is the thermal destruction or decomposition of material occurring in the absence of oxygen. In fast pyrolysis, the waste degenerates to give vapours, aerosols and some charcoal. After cooling and condensation, a dark brown liquid is formed which has a heating value about half that of conventional fuel oil. Virtually any form of organic waste can be considered for fast pyrolysis.

Gasification

Gasification is closely linked to pyrolysis. When waste material is heated with no more than around one-third of the amount of oxygen needed for efficient combustion, it gasifies to a mixture of carbon monoxide and hydrogen (synthesis gas or syngas) potentially with carbon dioxide and methane. The amount of oxygen and other conditions determine whether the biomass gasifies. Biomass and biowaste gasification can improve the efficiency of large-scale biomass power facilities and specialised facilities.

Plasma gasification

Plasma gasification is where waste is fed to a reactor where it is exposed to an electrically-generated plasma. The waste is heated to over 2,000 degrees Celsius, causing organic compounds to break down to form molecules such as hydrogen, carbon monoxide, carbon dioxide, water vapour and methane. The gas from the reactor is suitable as fuel for a gas-fired generation unit or can be used as a feedstock for chemical processes such as methanol production.

Good management of organic waste enables food and drink producers and hospitality businesses to reduce the disposal of organic waste to landfill. In turn this helps your business to meet legal, economic, stakeholder and media pressures.

Organic waste legal pressures

Managing your organic waste effectively will help you comply with legal requirements, such as regulations on animal by-products and landfill.

The Animal By-Products Regulations aim to control the risk of disease to both animals and the public. Animal by-products are allocated to one of three categories according to the risk they pose, and this category determines the waste management options permitted. Catering waste, former foodstuffs, and raw meat and raw fish from food manufacturers and food retailers are usually Category 3, the lowest risk.

Controls on waste disposed of to landfill are becoming increasingly tighter. Certain wastes are now banned, including liquid wastes. You or your waste contractor must also treat all waste in some way before it is sent to landfill as part of your duty of care for business waste.

Organic waste economic pressures

Reducing the amount of organic waste that you send to landfill will reduce your costs because food waste attracts the higher rate of landfill tax. Disposing of mixed waste to landfill sites is becoming increasingly less economically viable because of:

• annual increases in the landfill tax
• higher charges by operators to recoup the costs associated with stricter rules governing landfill design and operation
• the requirement to treat waste before consigning it to landfill

Organic waste stakeholder pressures

The environment is an increasingly important part of the corporate and societal agenda. Environmental performance and responsible behaviour in the community are increasingly important factors in winning and keeping new customers. Businesses are increasingly expected by their stakeholders - customers, investors, suppliers, media, etc - to demonstrate a commitment to minimising and managing waste.

Although organic waste management or treatment is important, it is not the most efficient use of resources for food and drink producers and hospitality businesses. The best approach is to avoid creating waste in the first place, as this will save you money.

If you can't avoid it, look at how you can reuse waste materials.

Food business waste reduction tips

To help prevent waste, take the following steps:

• Form a waste reduction team to lead initiatives to reduce and eliminate waste.
• Obtain support - the help and commitment of everyone in your business, including senior management, is essential for effective waste reduction.
• Measure - make an inventory of your materials and processes to identify ways to minimise waste.
• Prioritise - target major sources of waste first, as this should yield early successes and savings. Look at the largest quantities going to waste and at the highest net costs.
• Welcome ideas - talk to the key people involved in handling and dealing with each type of waste, and be prepared to challenge and question existing practices. You could ask why there is so much waste, whether anyone has looked at this as a problem before, whether there are processes that could be updated and what you think could be done to cut waste.

Putting waste reduction ideas into action

Your waste reduction team should be able to come up with a list of actions to reduce or eliminate waste. If necessary, hold an informal brainstorming session to get ideas. Estimate the costs and savings of different initiatives as accurately as possible.

You should also devise an action plan - for the short, medium and long term - with dates, costs and targets.

To be successful, you need to:

• be systematic - some changes can be introduced almost overnight, while others will take longer and need careful planning
• measure and quantify cost savings, payback periods and quantities of waste reduced
• communicate - this will help to motivate staff and keep the board supportive

Once you have implemented measures for reducing and reusing organic waste, the next step is to recycle organic waste that is left. This usually requires you to separate different types of waste.

Organic waste is not always welcomed by waste management businesses because:

• wet wastes such as food wastes are liable to decay and can cause smells
• wet wastes present a high pollution risk, particularly to water
• natural degradation can make landfill unstable
• uncontrolled production of landfill gas is hazardous and damaging to the environment
• it can be costly to transport

However, there are a number of relatively straightforward methods to treat organic material for recycling. On-site treatment of organic waste can substantially and quickly reduce the amount of waste material and the cost of disposal. If treated fully and appropriately organic waste can become a valuable resource as compost, energy or fertiliser.

However, if your business processes food or is involved in catering you cannot risk creating problems such as microbial hazards or odour. On-site solutions must, therefore, be both safe and 'biosecure' - preventing biological contamination and the spread of infectious organisms.

Regulatory issues with organic waste

Various environmental regulations determine what organic waste you can recycle. The Animal By-Products Regulations are key and you should check how these apply to you. The rules also vary depending on whether you are:

• processing your own waste
• processing and exporting products
• getting someone else to process your waste for you

Since organic waste is highly regulated, it is important to understand whether:

• your treatment choices comply with current legislation
• anyone to whom you transfer waste is using appropriate technology

There are significant costs associated with any method of disposal as well as substantial penalties for being ill-informed, so there can be real cost benefits in modern treatment, recycling and waste reduction.

Composting breaks down organic material to produce safe, stable reusable material - compost. The temperatures achieved during composting destroy any harmful pathogens present. You can compost most organic waste, but the method depends on the nature and amount of the waste and the level of regulation that applies.

Materials such as garden waste - so-called 'green waste' including grass cuttings, prunings and leaves - from your grounds can be composted easily outdoors. Material liable to cause smells may need to be put in a box or tank to minimise odour and prevent leaks of any liquids that may be produced.

The most appropriate composting method is likely to depend on how much waste you produce.

Composting small amounts of organic waste

Relatively small amounts of waste, eg leftover food from a small restaurant, can be treated in a 'back-door' composter similar to home compost bins. Such composting is lightly regulated providing any product is used only on site, eg for mulching flower beds around a hotel or kitchen. You should:

• ensure the composter is vermin-proof
• blend material likely to cause smells with garden wastes and other materials (eg cardboard) to reduce the risk
• aerate simple compost boxes by turning the contents (eg using a garden fork) regularly

You can also use this kind of composting at larger sites. You should establish a contained system to make it easier for staff to use and to keep the process clean.

Composting large amounts of organic waste

For larger quantities of green waste, you can generally carry out composting outdoors using relatively simple equipment such as tractors/loaders or tractor-drawn compost turners to aerate windrows. You may require additional equipment such as shredders.

These relatively simple operations tend to be labour-intensive and have a high energy cost per tonne. They may also result in poor product quality. Larger operations using specialist equipment are more likely to be successful but require investment in dedicated machinery. When deciding which machinery to use, capital cost may be less important than long-term operating and servicing costs.

Although large-scale composting is not appropriate for most businesses, there may be opportunities to form a partnership with neighbours. For example, a farm may be willing to compost rejects from a local vegetable processing plant.

The compost that you produce is likely to still be waste until it has been spread on land for beneficial purposes.

If you choose not to go down the quality protocol route the compost must be spread under either a waste exemption or a land-spreading permit. Most businesses will qualify for a waste exemption. In the unlikely event that you don't you will need to obtain a permit.

Wastes covered by the Animal By-products Regulations

Various requirements apply if material to be composted is covered under the Animal By-Products Regulations. Complying with the regulations is a requirement for any commercial waste food processing.

Food and drink producers and hospitality businesses could consider anaerobic digestion of their organic waste. This involves the treatment of organic material in the absence of oxygen (air). The digestion process involves degrading material with microbes but uses a different group of naturally occurring micro-organisms to composting. This process generally has three outputs:

• Digestate - a wetted, solid material that usually requires maturing or composting before it can be used, eg applied to soil.
• Liquid - may be rich in nutrients and can be used as a fertiliser.
• Biogas - can be used to generate electricity or burnt as a renewable fuel. It generally contains around 60 per cent methane, with carbon dioxide the other main component.

An important difference between composting and anaerobic digestion is that biogas is released during the fermentation process. Biogas is suitable for use in some gas engines and is often used in combined heat and power units to generate electricity and heat.

If you intend to set up your own anaerobic digestion system, check whether you need authorisation from the Northern Ireland Environment Agency. If you use a system operated by another organisation, check they are authorised to operate it.

The outputs from anaerobic digestion are still waste unless they have been produced on farms using certain waste types. They are therefore still subject to waste regulation and their use must be registered under a waste exemption or an environmental permit.

To make sure the use of anaerobic digestate isn't regulated by waste legislation you should meet the requirements of the quality protocol for anaerobic digestate.

Digester system design

There are various digester designs, each suited to different circumstances. The design of an anaerobic digestion system provides the optimum conditions in which micro-organisms can flourish and degrade the waste. This requires:

• a balanced and predictable internal environment
• control of the rate of input and output and process conditions such as temperature and acidity

Wet digestion of organic waste

This type of digester has technology that is proven, robust and relatively simple to operate. The digestion of dense materials such as food waste and similar solids/semi-solids requires their dilution in a large volume of water so any solid output will need to be dewatered. Liquid outputs can be recycled within the process to reintroduce the bacteria and reduce water use.

Dry digestion of organic waste

High solids processes are not dry. The waste is processed at 20 to 40 per cent moisture, generally as a pumpable mass blended to the correct consistency using specialist equipment and injected into the digester. Virtually no liquid make-up is required and the liquid output is modest. This liquid tends to have a relatively high nutrient content and is a useful fertiliser.

Dry digesters can be horizontal and may have a void above the digestion mass, which can act as a buffer for low pressure biogas production and storage. This removes the need for additional gas management and separate storage vessels.

Digester biosecurity

Traditional wastewater anaerobic digestion systems operate at a relatively low temperature of around 35°C. At these temperatures the mass is transformed substantially, coupled with biogas release, but harmful micro-organisms and parasites may not be eliminated. Organic wastes must be subjected to controlled pasteurisation involving temperatures of 55-70°C.

There are various other physical and chemical methods that food and drink producers and hospitality businesses can use to treat organic waste. However, these tend to be large-scale solutions, so smaller businesses are likely to need other organisations as partners or contractors.

Rendering

Rendering involves the partial recovery of materials from animal by-products (including former foodstuffs) by crushing and grinding, followed by heat treatment to reduce the moisture content and kill micro-organisms. Renderers process most animal by-products from the meat production chain to produce tallow and protein meal. Tallow is used in industries as diverse as paint manufacture and tyre production, as well as for fuel.

Autoclaving

Autoclaving is a conventional combination of heat treatment under pressure and has been used for many years as a sterilisation process. Heat is applied to material either directly as steam or by heating the vessel to release steam from the moisture content of the material being treated. This increases the pressure within the closed vessel. Organic waste such as food and vegetable residues, paper and cardboard etc will result in an organic 'wool' or fibre when treated in an autoclave.

Hydrolysis

Hydrolysis is a process in which chemical bonds are broken by the 'insertion' of water between the atoms in the chemical bond. This destroys the protein/amino acid framework of organic waste and is particularly suited to high risk wastes, such as high level animal by-product wastes.

Microwave treatment

Microwave treatment of organic waste tends to be small scale and is predominantly used to sterilise high risk material. Microwave systems are either batch or through-flow, and may be used alone or in combination with steam injection systems, which increase the efficiency of the microwave process and help to raise its temperature to pasteurisation levels.

Food and drink producers and hospitality businesses can consider various other treatment systems involving the use of heat. These all require specialist facilities.

Incineration

Incineration does not produce usable by-products, although the energy can be used to generate electricity. Many organic wastes have a high moisture content and may require drying before combustion. Incinerator plants that burn only animal carcasses or parts of carcasses must be approved under the Animal By-Products Regulations, but are exempt from more onerous waste incineration controls. However, plants that burn other animal by-products must be permitted or licensed by the Northern Ireland Environment Agency.

Pyrolysis

Pyrolysis is the thermal destruction or decomposition of material occurring in the absence of oxygen. In fast pyrolysis, the waste degenerates to give vapours, aerosols and some charcoal. After cooling and condensation, a dark brown liquid is formed which has a heating value about half that of conventional fuel oil. Virtually any form of organic waste can be considered for fast pyrolysis.

Gasification

Gasification is closely linked to pyrolysis. When waste material is heated with no more than around one-third of the amount of oxygen needed for efficient combustion, it gasifies to a mixture of carbon monoxide and hydrogen (synthesis gas or syngas) potentially with carbon dioxide and methane. The amount of oxygen and other conditions determine whether the biomass gasifies. Biomass and biowaste gasification can improve the efficiency of large-scale biomass power facilities and specialised facilities.

Plasma gasification

Plasma gasification is where waste is fed to a reactor where it is exposed to an electrically-generated plasma. The waste is heated to over 2,000 degrees Celsius, causing organic compounds to break down to form molecules such as hydrogen, carbon monoxide, carbon dioxide, water vapour and methane. The gas from the reactor is suitable as fuel for a gas-fired generation unit or can be used as a feedstock for chemical processes such as methanol production.

Good management of organic waste enables food and drink producers and hospitality businesses to reduce the disposal of organic waste to landfill. In turn this helps your business to meet legal, economic, stakeholder and media pressures.

Organic waste legal pressures

Managing your organic waste effectively will help you comply with legal requirements, such as regulations on animal by-products and landfill.

The Animal By-Products Regulations aim to control the risk of disease to both animals and the public. Animal by-products are allocated to one of three categories according to the risk they pose, and this category determines the waste management options permitted. Catering waste, former foodstuffs, and raw meat and raw fish from food manufacturers and food retailers are usually Category 3, the lowest risk.

Controls on waste disposed of to landfill are becoming increasingly tighter. Certain wastes are now banned, including liquid wastes. You or your waste contractor must also treat all waste in some way before it is sent to landfill as part of your duty of care for business waste.

Organic waste economic pressures

Reducing the amount of organic waste that you send to landfill will reduce your costs because food waste attracts the higher rate of landfill tax. Disposing of mixed waste to landfill sites is becoming increasingly less economically viable because of:

• annual increases in the landfill tax
• higher charges by operators to recoup the costs associated with stricter rules governing landfill design and operation
• the requirement to treat waste before consigning it to landfill

Organic waste stakeholder pressures

The environment is an increasingly important part of the corporate and societal agenda. Environmental performance and responsible behaviour in the community are increasingly important factors in winning and keeping new customers. Businesses are increasingly expected by their stakeholders - customers, investors, suppliers, media, etc - to demonstrate a commitment to minimising and managing waste.

Although organic waste management or treatment is important, it is not the most efficient use of resources for food and drink producers and hospitality businesses. The best approach is to avoid creating waste in the first place, as this will save you money.

If you can't avoid it, look at how you can reuse waste materials.

Food business waste reduction tips

To help prevent waste, take the following steps:

• Form a waste reduction team to lead initiatives to reduce and eliminate waste.
• Obtain support - the help and commitment of everyone in your business, including senior management, is essential for effective waste reduction.
• Measure - make an inventory of your materials and processes to identify ways to minimise waste.
• Prioritise - target major sources of waste first, as this should yield early successes and savings. Look at the largest quantities going to waste and at the highest net costs.
• Welcome ideas - talk to the key people involved in handling and dealing with each type of waste, and be prepared to challenge and question existing practices. You could ask why there is so much waste, whether anyone has looked at this as a problem before, whether there are processes that could be updated and what you think could be done to cut waste.

Putting waste reduction ideas into action

Your waste reduction team should be able to come up with a list of actions to reduce or eliminate waste. If necessary, hold an informal brainstorming session to get ideas. Estimate the costs and savings of different initiatives as accurately as possible.

You should also devise an action plan - for the short, medium and long term - with dates, costs and targets.

To be successful, you need to:

• be systematic - some changes can be introduced almost overnight, while others will take longer and need careful planning
• measure and quantify cost savings, payback periods and quantities of waste reduced
• communicate - this will help to motivate staff and keep the board supportive

Once you have implemented measures for reducing and reusing organic waste, the next step is to recycle organic waste that is left. This usually requires you to separate different types of waste.

Organic waste is not always welcomed by waste management businesses because:

• wet wastes such as food wastes are liable to decay and can cause smells
• wet wastes present a high pollution risk, particularly to water
• natural degradation can make landfill unstable
• uncontrolled production of landfill gas is hazardous and damaging to the environment
• it can be costly to transport

However, there are a number of relatively straightforward methods to treat organic material for recycling. On-site treatment of organic waste can substantially and quickly reduce the amount of waste material and the cost of disposal. If treated fully and appropriately organic waste can become a valuable resource as compost, energy or fertiliser.

However, if your business processes food or is involved in catering you cannot risk creating problems such as microbial hazards or odour. On-site solutions must, therefore, be both safe and 'biosecure' - preventing biological contamination and the spread of infectious organisms.

Regulatory issues with organic waste

Various environmental regulations determine what organic waste you can recycle. The Animal By-Products Regulations are key and you should check how these apply to you. The rules also vary depending on whether you are:

• processing your own waste
• processing and exporting products
• getting someone else to process your waste for you

Since organic waste is highly regulated, it is important to understand whether:

• your treatment choices comply with current legislation
• anyone to whom you transfer waste is using appropriate technology

There are significant costs associated with any method of disposal as well as substantial penalties for being ill-informed, so there can be real cost benefits in modern treatment, recycling and waste reduction.

Composting breaks down organic material to produce safe, stable reusable material - compost. The temperatures achieved during composting destroy any harmful pathogens present. You can compost most organic waste, but the method depends on the nature and amount of the waste and the level of regulation that applies.

Materials such as garden waste - so-called 'green waste' including grass cuttings, prunings and leaves - from your grounds can be composted easily outdoors. Material liable to cause smells may need to be put in a box or tank to minimise odour and prevent leaks of any liquids that may be produced.

The most appropriate composting method is likely to depend on how much waste you produce.

Composting small amounts of organic waste

Relatively small amounts of waste, eg leftover food from a small restaurant, can be treated in a 'back-door' composter similar to home compost bins. Such composting is lightly regulated providing any product is used only on site, eg for mulching flower beds around a hotel or kitchen. You should:

• ensure the composter is vermin-proof
• blend material likely to cause smells with garden wastes and other materials (eg cardboard) to reduce the risk
• aerate simple compost boxes by turning the contents (eg using a garden fork) regularly

You can also use this kind of composting at larger sites. You should establish a contained system to make it easier for staff to use and to keep the process clean.

Composting large amounts of organic waste

For larger quantities of green waste, you can generally carry out composting outdoors using relatively simple equipment such as tractors/loaders or tractor-drawn compost turners to aerate windrows. You may require additional equipment such as shredders.

These relatively simple operations tend to be labour-intensive and have a high energy cost per tonne. They may also result in poor product quality. Larger operations using specialist equipment are more likely to be successful but require investment in dedicated machinery. When deciding which machinery to use, capital cost may be less important than long-term operating and servicing costs.

Although large-scale composting is not appropriate for most businesses, there may be opportunities to form a partnership with neighbours. For example, a farm may be willing to compost rejects from a local vegetable processing plant.

The compost that you produce is likely to still be waste until it has been spread on land for beneficial purposes.

If you choose not to go down the quality protocol route the compost must be spread under either a waste exemption or a land-spreading permit. Most businesses will qualify for a waste exemption. In the unlikely event that you don't you will need to obtain a permit.

Wastes covered by the Animal By-products Regulations

Various requirements apply if material to be composted is covered under the Animal By-Products Regulations. Complying with the regulations is a requirement for any commercial waste food processing.

Food and drink producers and hospitality businesses could consider anaerobic digestion of their organic waste. This involves the treatment of organic material in the absence of oxygen (air). The digestion process involves degrading material with microbes but uses a different group of naturally occurring micro-organisms to composting. This process generally has three outputs:

• Digestate - a wetted, solid material that usually requires maturing or composting before it can be used, eg applied to soil.
• Liquid - may be rich in nutrients and can be used as a fertiliser.
• Biogas - can be used to generate electricity or burnt as a renewable fuel. It generally contains around 60 per cent methane, with carbon dioxide the other main component.

An important difference between composting and anaerobic digestion is that biogas is released during the fermentation process. Biogas is suitable for use in some gas engines and is often used in combined heat and power units to generate electricity and heat.

If you intend to set up your own anaerobic digestion system, check whether you need authorisation from the Northern Ireland Environment Agency. If you use a system operated by another organisation, check they are authorised to operate it.

The outputs from anaerobic digestion are still waste unless they have been produced on farms using certain waste types. They are therefore still subject to waste regulation and their use must be registered under a waste exemption or an environmental permit.

To make sure the use of anaerobic digestate isn't regulated by waste legislation you should meet the requirements of the quality protocol for anaerobic digestate.

Digester system design

There are various digester designs, each suited to different circumstances. The design of an anaerobic digestion system provides the optimum conditions in which micro-organisms can flourish and degrade the waste. This requires:

• a balanced and predictable internal environment
• control of the rate of input and output and process conditions such as temperature and acidity

Wet digestion of organic waste

This type of digester has technology that is proven, robust and relatively simple to operate. The digestion of dense materials such as food waste and similar solids/semi-solids requires their dilution in a large volume of water so any solid output will need to be dewatered. Liquid outputs can be recycled within the process to reintroduce the bacteria and reduce water use.

Dry digestion of organic waste

High solids processes are not dry. The waste is processed at 20 to 40 per cent moisture, generally as a pumpable mass blended to the correct consistency using specialist equipment and injected into the digester. Virtually no liquid make-up is required and the liquid output is modest. This liquid tends to have a relatively high nutrient content and is a useful fertiliser.

Dry digesters can be horizontal and may have a void above the digestion mass, which can act as a buffer for low pressure biogas production and storage. This removes the need for additional gas management and separate storage vessels.

Digester biosecurity

Traditional wastewater anaerobic digestion systems operate at a relatively low temperature of around 35°C. At these temperatures the mass is transformed substantially, coupled with biogas release, but harmful micro-organisms and parasites may not be eliminated. Organic wastes must be subjected to controlled pasteurisation involving temperatures of 55-70°C.

There are various other physical and chemical methods that food and drink producers and hospitality businesses can use to treat organic waste. However, these tend to be large-scale solutions, so smaller businesses are likely to need other organisations as partners or contractors.

Rendering

Rendering involves the partial recovery of materials from animal by-products (including former foodstuffs) by crushing and grinding, followed by heat treatment to reduce the moisture content and kill micro-organisms. Renderers process most animal by-products from the meat production chain to produce tallow and protein meal. Tallow is used in industries as diverse as paint manufacture and tyre production, as well as for fuel.

Autoclaving

Autoclaving is a conventional combination of heat treatment under pressure and has been used for many years as a sterilisation process. Heat is applied to material either directly as steam or by heating the vessel to release steam from the moisture content of the material being treated. This increases the pressure within the closed vessel. Organic waste such as food and vegetable residues, paper and cardboard etc will result in an organic 'wool' or fibre when treated in an autoclave.

Hydrolysis

Hydrolysis is a process in which chemical bonds are broken by the 'insertion' of water between the atoms in the chemical bond. This destroys the protein/amino acid framework of organic waste and is particularly suited to high risk wastes, such as high level animal by-product wastes.

Microwave treatment

Microwave treatment of organic waste tends to be small scale and is predominantly used to sterilise high risk material. Microwave systems are either batch or through-flow, and may be used alone or in combination with steam injection systems, which increase the efficiency of the microwave process and help to raise its temperature to pasteurisation levels.

Food and drink producers and hospitality businesses can consider various other treatment systems involving the use of heat. These all require specialist facilities.

Incineration

Incineration does not produce usable by-products, although the energy can be used to generate electricity. Many organic wastes have a high moisture content and may require drying before combustion. Incinerator plants that burn only animal carcasses or parts of carcasses must be approved under the Animal By-Products Regulations, but are exempt from more onerous waste incineration controls. However, plants that burn other animal by-products must be permitted or licensed by the Northern Ireland Environment Agency.

Pyrolysis

Pyrolysis is the thermal destruction or decomposition of material occurring in the absence of oxygen. In fast pyrolysis, the waste degenerates to give vapours, aerosols and some charcoal. After cooling and condensation, a dark brown liquid is formed which has a heating value about half that of conventional fuel oil. Virtually any form of organic waste can be considered for fast pyrolysis.

Gasification

Gasification is closely linked to pyrolysis. When waste material is heated with no more than around one-third of the amount of oxygen needed for efficient combustion, it gasifies to a mixture of carbon monoxide and hydrogen (synthesis gas or syngas) potentially with carbon dioxide and methane. The amount of oxygen and other conditions determine whether the biomass gasifies. Biomass and biowaste gasification can improve the efficiency of large-scale biomass power facilities and specialised facilities.

Plasma gasification

Plasma gasification is where waste is fed to a reactor where it is exposed to an electrically-generated plasma. The waste is heated to over 2,000 degrees Celsius, causing organic compounds to break down to form molecules such as hydrogen, carbon monoxide, carbon dioxide, water vapour and methane. The gas from the reactor is suitable as fuel for a gas-fired generation unit or can be used as a feedstock for chemical processes such as methanol production.