Typically waste collection vehicles are weighed at a weighbridge (large scales) on arrival. After unloading, compactors or bulldozers then spread and compact the waste, and typically cover it with soil, wood chippings or other materials. The waste collection vehicles usually pass through a week cleaning facility before leaving – and, if needed, back through the weighbridge to calculate the waste deposited.
Landfill sites can create environmental problems such as water pollution, soil contamination and vermin. Decaying organic waste also emits methane, a greenhouse gas that is 34 times more potent than carbon dioxide. (Organic waste is the remains of once-living organisms such as plants and animals, and their waste. Food waste is an example of organic waste).
The European Landfill Directive came into effect in the EU July 1999 and the UK in 2002. It aims to decrease the environmental impacts of landfills, as well as the risk to human health. It sets:
1. Minimum standards for the location, design, construction and operation of landfills.
2. Rules defining waste and landfills types.
Historically the UK practiced what it known as co-disposal, with hazardous and non-hazardous wastes landfilled together. Since July 2004 though, landfills have been segregated – with landfills for: hazardous* waste only; non-hazardous waste only; inert** waste only.
*Hazardous waste includes most paints, chemicals, light bulbs, fluorescent tubes, spray cans, fertilizer
**Inert waste includes construction and demolition waste, dirt, rocks
3. Targets for reducing the amount of Biodegradable Municipal Waste (BMW)* sent to landfill.
In other EU states, targets were established for 2006, 2009 and 2016. However, because the UK previously relied so heavily on landfilling (over 80% of waste was being landfilled in 1995), it was granted an extra 4 years. The UK’s targets are:
• By 2010 reduce the biodegradable waste landfilled to 75% of that produced in 1995.
• By 2013 reduce the biodegradable waste landfilled to 50% of that produced in 1995.
• By 2020 reduce the biodegradable waste landfilled to 35% of that produced in 1995.
The UK adopted a Landfill Allowances Trading Scheme (LATS) and Landfill Allowance Schemes (LAS) to help achieve these targets.
In England LATS are used. Each waste disposal authority (WDA) is allocated a landfill allowance per year for their biodegradable municipal waste. However they’re also allowed to trade their allowance with other authorities and bank an amount for future years if their allocation isn’t fully used – among other options.
In Wales, Scotland and Northern Ireland the scheme is known as the Landfill Allowances Scheme (LAS) with no trading between WDAs being permitted.
*Municipal solid waste (MSW) is what’s commonly known as rubbish or refuse. It is consists of everyday items discarded by the public and collected by a ‘municipality’ (council or borough in the UK). Most definitions of MSW do not include industrial wastes, agricultural wastes, medical waste, radioactive waste or sewage sludge.
Incineration involves the combustion (burning) of organic materials in waste. The waste is converted into ash, gas and heat. The heat is used to boil water, which powers steam generators that produce electricity and heat to be used in homes and businesses.
One benefit of incineration over landfill is the reduction in waste volume – modern incinerators reduce the volume of the original waste by 95-96% percent, making incineration a popular option in countries such as Japan where land is scarce.
Modern incinerators are also equipped to prevent pollutants in the gas from entering the atmosphere. For example any acidic acids in the smoke are now neutralised; back in the 1980s, incinerators were accused of causing acid rain.
The term ‘in-vessel composting’ covers a wide range of composting systems, all of which involve the enclosed composting of waste – allowin oxygen levels, temperature and moisture to be controlled.
IVC can be a one or two stage process: the Animal By-Products Regulations (ABPR), introduced in 2003 to reduce health and environmental risks, allow waste excluding meat to be treated in one stage but require waste including meat to undergo two stages.
In stage one, food and garden waste is firstly shredded to a uniform size and loaded into a bay or tunnel. Naturally-occurring micro-organisms, already present in the waste, start breaking it down. The process draws oxygen from the air and raises the temperature to the 60-70ºC, which is needed to kill weed seeds and pathogens. Compost is produced, with water vapour and carbon dioxide given off as by-products.
If needed (if the original waste includes meat), the material is transferred to a second ‘barrier’ to ensure the material is fully sanitised. The two stages each take between 7 days and 3 weeks.
The compost is then left to mature in an open windrow* for approximately 10-14 weeks to ensure stabilisation. Screening takes place to produce different quality compost.
*A windrow is simply a heap or row of materials.
PAS 100 stands for Publicly Available Specification 100. You might also see it written as ‘BSI PAS 100’. This being UK phrasing, with BSI standing for British Standards Institution.
The PAS 100 is an industry standard for compost. It looks at the raw materials going in, production methods, quality control and lab testing – all to ensure the compost is of a high quality for agriculture and horticulture.
(N.B. With regards food packaging: composting facilities compliant with PAS 100 can only accept packaging that’s been certified as compostable under EN 13432).
In the same fashion, PAS 110 is a standard for digestate (bio-fertiliser). Digestate is produced when waste is treated using Anaerobic Digestion. Just as compost is produced from In-Vessel Composting. For an explanation of Anaerobic Digestion, see point 6. below.
In open windrow composting, garden waste is left to break in the presence of oxygen – in the open air or within large covered areas. This differs from enclosed In-Vessel Composting.
Windrow composting also faces different constraints under the Animal By-Products Regulations. Because catering* and animal wastes are categorised as Animal By-Products (ABPs) they are not accepted in windrow composting like they are in IVC. Windrow composting accepts garden waste only.
*Catering waste is defined as all waste food, including used cooking oil, that’s originated in restaurants, catering facilities and kitchens, including household kitchens. It excludes waste food originating in supermarkets, butchers and factories, which produce food for retail sale.
In Anaerobic Digestion (AD) biodegradable waste breaks down in the absence of oxygen (in contrast to In-Vessel Composting where oxygen is present). It’s widely used to treat wastewater in the UK, and increasingly used for food waste and manure.
In the first stage, ‘pre-treatment’, the materials are mixed together to ensure the right consistency; water may be added. The material is then screened for contaminants, such as plastic and grit. Packaged food often has its packaging removed at this stage as well (although in some AD plants, this ‘depackaging’ happens at the end).
Next, the materials are fed into a digestor. It’s here that they break down into digestate (a bio-fertiliser that can be used on the land for healthy plant growth and soil), as well as biogas (mostly methane and Co2).
Because of this biogas, AD is another Waste-to-energy (WtE) or energy-from-waste (EfW) technology like incineration (point 1. above). Waste-to-energy is all about ‘energy recovery’ from waste. That is, generating electricity and/or heat from waste – either directly from the combustion of waste like incineration, or by producing a combustible fuel like AD.
The biogas produced in AD can be used directly as fuel, in combined heat and power gas engines, or upgraded to biomethane (Co2 and other contaminants are removed leaving a gas that’s 95% methane). This biomethane is injected into the gas grid or used as vehicle fuel.
There are different kinds of recycling collection services:
• Source-separated recycling: recyclables are separated into their material streams e.g. paper, plastic at the point they are discarded. They’re also collected separately.
• Kerbside sort’ schemes: recyclables are sorted at the kerbside, before they enter the lorry i.e. even when recyclables are thrown away together, into one bin, if they’re sorted at the kerbside, it’s still coined a ‘separate collection’.
Paper/card only segregated:
• ‘Two-stream’: paper and card is put into one compartment of the lorry, whilst plastic, glass and metal (e.g. aluminium cans) are placed in another.
• ‘Co-mingled’ collections: all recyclables are put into the lorry together, before going to a Materials Recovery Facility (MRF) for sorting.
At the Material Recycling Facility:
1. The co-mingled materials are loaded onto conveyors.
2. Incorrect items such as crisp packets and plastics bags are removed.
3. A vibrating machines separates the cardboard and paper from the rest of the materials. The different types of paper are then sorted by hand and then baled.
4. The remaining recyclables continue on another conveyor where steel and tins are removed using magnets.
5. Different types of plastic are identified and separated using optical scanners.
6. A special kind of magnet is used to sort aluminium cans.
7. Glass is the remaining material and this drops off the end of the conveyor.
New laws came into effect on 1st January 2014 asking Scottish businesses were to comply with separate recycling collections. By 2025, Scotland aims to to recycle 70% of the country’s waste and send just 5% to landfill.
England & Wales
The European Waste Framework Directive states that from 1st January 2015, waste collection authorities must collect household paper, plastic, metal and glass separately.
This is to help meet the directive’s target of recycling, or preparing for reuse, 50% of household waste by 2020.
The most recognised symbols in the UK are from Recycle Now, an initiative of the government waste body WRAP (Waste & Resources Action Programme). Their on-pack labelling on food items, for example, looks like:
“Widely Recycled” means 75% of people have access to recycling facilities for these items.
“Check locally” means 20% – 75% of people have access to recycling facilities for these items.
“Not recycled” means less than 20% of people have access to recycling facilities for these items.
The Mobius Loop is a universally recognised symbol and tells us an object is recyclable. Although whether the object can be recycled in a particular recycling centre is dependent on the facilities available.
Like this however (see left), the Mobius Loop does not indicate that the object contains any recycled content. Only when the loop contains a percentage sign, does it indicate recycled content. A Mobius Loop showing 50%, for example, implies the item contains 50% recycled content.
Only by knowing about the different plastic type can you know if the object is recyclable. For example:
– PET or PETE (Polyethylene terephthalate) is widely recyclable in the UK. Example of an object made from PET: mineral water bottle.
– PP (Polypropylene) on the other hand is rarely recyclable. Example of an object made from PP: bottle lid.
The number inside the loop indicates the type of polymer.
It is in fact a scheme covered under the European “Packaging and Packaging Waste Directive – 94/62/EC”. It means that the manufacturer contributes towards the cost of recovery and packaging.
Similarly the Tidyman is not a recycling symbol. It’s merely to convey the message ‘Do not litter’.
Most glass bottles and jars are suitable for recycling even if they do not display this symbol.
The wood used in objects showing this symbol has come from a forest certified by the Forest Stewardship Council (FSC). It means the wood used is sustainably produced, and that you are not contributing to the destruction of the world’s forests.
This indicates an object has been certified by the National Association of Paper Merchants (NAPM), as being made from waste paper or waste cardboard. There are 3 variations of the symbol, depending on whether the object contains 50%, 75% or 100% recycled material.
The directive places responsibility for the disposal of waste electrical equipment on the manufacturer. The manufacturer should establish an infrastructure for collecting WEEE, so that consumers can return the WEEE free of charge. The manufacturer is also obliged to use the collected waste in an eco-friendly manner, either by ecological disposal or by reuse/refurbishment.