Waste Minimisation

Each year Leicestershire produces approximately 330,000 tonnes of waste and this is continuing to rise. This equates to 1.3 tonnes of rubbish per household. This is the same weight as an average family car. In 2003/04 just over 25% of this waste was recycled. It is essential that we turn this growth trend around and not only recycle but also reduce the waste we produce. It currently costs taxpayers £20 million each year to deal with the waste in Leicestershire. It would clearly be beneficial if every household could reduce the quantity of waste it produces for disposal by practising waste minimisation. If we concentrate on decreasing the quantity of waste produced we can reduce the costs and energy used. The less waste we introduce into the waste stream the less harm we inflict on our environment.The Waste Hierarchy provides a sliding scale on the best ways to deal with our waste. The best option is at the top of the scale and the least preferred option is at the bottom.

Reduce

It is important to reduce the amount of waste we produce. This can be done in many ways including those listed below. It is better to reduce the amount of waste we produce so we send less to landfill.

Shop smart, consider the packaging that foods are contained in
Buy loose fruit and vegetables for example
Consider buying in bulk to minimise packaging waste
Dont buy disposable items such as razors and pens
Use re-usable boxes for packed lunches and storage of food in the fridge rather than foil or cling film
Stop junk mail. Contact the Mailing Preference Service, DMA House, 70 Margaret Street, London, W1W 8SS. Telephone 0207 291 3310, or visit their website at www.mpsonline.org.uk
Find out more about home composting so you can help to reduce the amount of waste going to landfill

Re-use

Reusable Bag
There are numerous ways that we can re-use products that we buy. A number of these are listed below, but there will be many more that you may come up with yourself.

Use re-usable Nappies

Buy re-useable carrier bags from supermarkets
Use re-chargeable batteries
Buy re-useable items such as jam jars
Donate old clothes and shoes
Re-use the back of paper for scrap paper
Re-use ice cream tubs as storage containers or lunch boxes

Recycle

Kerbside Recycling
Many materials are collected across Leicestershire, which are taken to be recycled. There are bring sites located across Leicestershire as well as the fourteen Recycling and Household Waste Sites. In addition there are kerbside collections in each of the Seven districts collecting a variety of materials.

The materials collected are listed below (this may vary depending on the site)

Paper
Card
Glass Bottles and Jars
Plastic bottles
Scrap Metal
Green Waste
Textiles
Engine Oil
Car Batteries
Fridges
White Goods
Wood
Mobile Phones
Batteries

Find out what materials are accepted at each site

Energy Recovery

There are other technologies which offer an alternative to landfill and enable energy recovery from waste.

Incineration

Incineration flow diagram
Once we have reduced, re-used and recycled, the remaining waste can be incinerated at 'Energy from Waste' plants. Waste is stored at the plants until it is needed to fuel the boilers to create energy. The most widely used process is the 'mass burn'.

The mass burn involves rubbish being burnt on a moving grate. Air is normally injected both above and below the grate to make sure that the rubbish is burnt properly The inside of the boiler's combustion chamber is filled with metal pipes, which are filled with water. The water in the pipes is heated and turns into steam when the waste is burnt. It is this steam that turns the blades of the turbine, which is like a giant propeller. The rapid rotation of the turbine is used to turn an electromagnet that produces the electricity. Around 10% of this electricity is used to run the plant and the rest is sold outside.

Once the steam has turned the turbines it is cooled and turned back into water, This water is then used to start the whole process again. Once the process is complete there is only ash left in the combustion chamber. The ash is passed along a conveyor belt, which passes by a magnet where any magnetic metals are removed. The remaining ash is then sent to landill and in some instances used for road contruction.

When waste is burnt it reduces the mass of waste going to landfill as well as reducing the amount of fossil fuel used to create electricity.

Pyrolysis

Pyrolysis is a thermal process where high temperatures (of around 500oC) are used to break down waste in the absence of oxygen. The process produces three end products; char (or ash), bio-oil and a synthetic gas. The solid char contains valuable carbon and mineral materials, which can be processed further to release this energy. The bio-oil can be used to fuel power stations and the gas is a clean fuel, which has a high calorific value.

Gasification

Gasification is a similar process to pyrolysis wherby the same three products are produced. Gasification however uses higher temperatures of around 2000oC and unlike pyrolysis uses controlled amounts of oygen and water in the process.

Gassification produces a gas called syngas, which can be used as an alternative to fossil fuels in generating electricity.

Anaerobic Digestion

Anaerobic Digestion is a process similar to composting which can treat all of our organic material. Organic waste is taken to a specialised plant and placed in an enclosed chamber for 10-25 days under controlled conditions. Anaerobic means 'in the absence of oxygen' which is the main difference between this process and composting. The absence of oxygen makes the waste decompose rapidly due to the bacteria that thrive in these conditions. This process produces biogas and a solid material called a digestate.

Biogas is a gas, which can be used as a fuel to make electricity. Many sewage treatments use this process and the gas produced is used to heat and power the plant.

The digestate can be seperated out into fibre and liquor. The liquid can be used as agricultural fertiliser and the solid is used as soil conditioner.

For further information on Anaerobin Digestion and to find out about the availability of grants to businesses in Leicestershire

MBT - Mechanical Biological Treatment

MBT systems fall into 2 categories:

1. Mechanical Treatment followed by Biological Treatment

Mechanical treatment removes glass, plastics and metals from household waste, these materials can then be recycled. The remaining fraction will then consist mainly of organic waste, which then enters the next stage of the process.

The biological treatment can incorporate anaerobic digestion or composting, this reduces the volume of organic waste and produces a compost-like product although this would not be the same quality as the compost you use in your garden.

2. Biological Treatment followed by Mechanical Treatment

The waste is shredded and dried, it is then mechanically sorted. Metals are removed using magnets and sent for recycling. Glass and grit is also removed and can be used for aggregate. The dried organic waste can be used as landfill cover, or made into pellets for use as fuel.

Disposal

Landfill Site
Finally there is the disposal of waste. Once we have reduced, re-used and recycled as much as possible of the materials in our waste bin, what is left has to go for disposal. Disposal involves the containment of waste with no energy recovery, most often in landfill sites or by incineration. If we maximise resource recovery we will reduce our demand on the earth’s natural resources.