Environmental Management ENV111
We have left a greater mark on the Earth than any other species. Waste has a significant effect on the environment and its reduction must play a part in our responsible stewardship of this planet on which we are merely tenants. The true cost of waste is often overlooked and includes cost of:- purchase & transport of materials wasted, storage of waste, loss of income which could have been gained from recovery of waste and loss of amenity at disposal site and access routes.
Municipal solid waste forms a small proportion of total waste at 7% (Figure 1 shows estimated UK waste), and household solid waste (HSW) forms by far the major part of this figure, therefore, for the purpose of this exercise, the terms can be interchangeable. HSW consists of, in order of magnitude:-
The type of materials used has changed distinctly, even in the last generation or two. Packaging such as glass milk bottles and paper bags are being superceded by plastics and gone is the idea of furniture to last a lifetime or more. Many such moves, though making consumer financial savings and greater producer profit, are not perhaps as sustainable as older methods.
Figure 1 - Estimated Total Annual Waste Arisings UK (100%=414Mte)
Landfill, at 83%, is by far the greatest destination for household solid waste (Figure 2 shows the final destinations of waste in England & Wales 1995/6, 100%=22.41Mt) and this is reflected in local data from Lancaster's Salt Ayre waste disposal site (Figure 3 shows a five week sample in 1997, 100%=5431te ). Waste can be handled by several methods, i.e. Minimise, Salvage and Reuse, Recycle, Incinerate, Landfill.
Figure 2 - Treatment & disposal of MSW in England & Wales 1995/6 (100%=22.41Mt)
Figure 3 - Salt Ayre Household Solid Waste (100%=5431te)
This usually involves a major culture change and embraces both manufacturer and consumer. The manufacturer can contribute through source reduction, which can also have benefits in lower material costs, in turn benefiting the consumer. Types of source reduction include, for example, changes to packaging or products (See Appendix).
3.2 Salvage & Reuse
Local household waste sites currently recover 'bric a brac' (Plate 1) however must be wary of selling goods to the public due to trading regulations; such items as televisions can only be sold to contractors who undertake only to use items for spares; otherwise the public liability of faults would be onerous.
The re-processing of such items as glass is now well established in the UK, but infrastructure is weak. More people would recycle if kerbside collections were more widespread. There must be sufficient infrastructure to handle this increase and likewise markets must favour recycled materials. Landfill Tax encourages waste centres to recover & recycle as much as possible. Green waste is now composted, bagged and sold. In recent years, scrap newsprint has dropped from £40/te to almost zero; household waste centres only handle it due to contractual reasons imposed by local government and to avoid landfill tax. (Plates 2,3 4 & 5).
Plate 1 - Salt Ayre - Bric a Brac Compound
Plate 2 - Salt Ayre Household Waste Centre
Plate 3 - Material Recycling Facility paper bales
Plate 4 - Salt Ayre - MRF Fridge compound
Plate 5 - Salt Ayre - MRF plastic bottle bales (HDPE, PET & PVC)
|The government target is 25% recycling of HSW by 2000 and to recover, including energy from waste & composting, 40% by 2005. The current national figure is 7% set against 16% for Lancashire (Figure 3). I carried out a trial during one week during October 1997 to see how feasible this recycling target is. Our house has a garden with 2m x 1m x1m compost bin and garage for storage of recycling items. The family consists of 2 adults and 3 children and this trial reflects our normal recycling activities without going to special measures. The trial revealed a staggering 61% recycling rate (Figure 4 shows one week in 1997, 100%=12kg ), therefore implying that the 25% target may potentially be exceeded significantly, subject to infrastructure and economics.||
Figure 4 - Household solid waste trial
People have burned small household solid waste for many years although this has reduced as open hearth fires have been replaced by other heat sources. Incineration comes in two forms, both of which result in landfill:- simple incineration or incineration with energy recovery, either in the form of electricity alone or with hot water supplied to nearby consumers. These currently form 4%* and 5% respectively of UK waste disposal (figure 3) (*this figure = 5% if Refuse Derived Fuel is included). Waste to energy plants benefit from the None Fossil Fuel Obligation which ties electricity companies to buying from such plants, one combined scheme in South East London generates 35Mw and currently earns 60% of income from electricity sales. Income from this disposal method, from £4/te upwards compares well with the cost of landfill tax at over £2/te. Incineration has the benefit in large conurbations of disposing of HSW when landfill sites where not available locally and of having a market for energy output; the capital cost may be easier to recoup in large conurbations, but smaller ones may not have the turnover to justify energy recovery plants. Furthermore it stabilises the waste and reduces it to typically 40% original volume. On the down side however, it also concentrates certain toxic substances such as heavy metals and produces large amounts of ash, both of which require licensed disposal sites. Older incinerators have to conform to stringent EU toxic emission standards. Although this has lead to the introduction of cleaner incineration, the public preconception is of black smoke, smells and heavy traffic, making a new plant a difficult proposition. Ironically, a modern waste to energy plant is probably the most safe and efficient solution to the problem; waste gasses are sprayed with urea to remove nitrogen dioxide and activated carbon removes toxic heavy metals, dioxins and furans before being sprayed with lime, bagged and sent for landfill after filtration.
At 83%, this forms the major part of HSW disposal (Figure 2). Uncontrolled methane leakage, toxic substances and general leachate are hazards still experienced, however tighter controls following the 1993 Royal Commission on Environmental Pollution should reduce the causes of these problems. Rainfall and air feed the decomposition of non inert items, producing heat and such gasses as carbon dioxide, methane and hydrogen sulphide. Leachate from toxic products and heavy metals is not usually a problem as they are firmly bound to the deposited material but salts and organic products may be and therefore measures need to be taken. Sites above the skyline can have more of an impact visually whereas sites below have less impact and may also make use of redundant quarries; but, even though five times as much extraction takes place than landfill, quarries are often unsuitable due to geography or geology. Deeper landfill sites also enable more efficient recovery of methane which is burned to produce modest amounts of electricity; volume CO2 produced from CH4 is environmentally less damaging than the CO2.
Improved awareness is required by manufacturers and consumers. Waste handling must move towards recycling and energy recovery. Landfill Tax has proved that changes in attitude of public and industry are best motivated by economics.
Mark Twain is reputed to have said
"Don't go around thinking the World owes you something
- the World owes you nothing, it was here first"
Sadly, this view is lacking in the so called developed world. Would people be more concerned if they had the total waste they were expected to generate in their lifetime, some 20 tonnes, dropped on them at a crucial moment in their life, such as their wedding?
Reduction In Weight - An early 1970's plastic milk bottle weighed 95g as opposed to one of the 1990's of 60g.
Replacement - shrink wrap polythene is being used in preference to cardboard packing. It is questionable that when all external costs are considered, in addition to the energy efficiency of polythene against cardboard, whether the polythene actually is better.
Bulk Packaging- fresh products being shipped in large containers rather than individually wrapped
Composite Packaging - more efficient packaging having a higher strength/weight (or volume) ratio than other packaging.
Consumable Packaging - In the 1980's, some detergent manufacturers produced packaging in dissolvable containers. More recently, UK shops are selling items (such as bathroom soap) in cloth string-tie bags or decorated cardboard boxes, intended for secondary use such as jewellery boxes.
Extended Packaging Life- Refillable containers have been available since the early 1990's, such as bathroom consumables (Body Shop shampoos etc).
Product Redesign - reduces amount of packaging required, for example clothes washing powders/liquids are now available concentrated.
Other Source Reduction Methods - to reduce waste, such as recycling, composting and even photocopying on two sides of sheets or removing junk mail from mailing lists!
Market Forces - Packaging manufacturers by reducing volume are also becoming more profitable, furthermore, reduction improves is good publicity as the public demands greener policies. A US survey showed small decline in packaging as part of total waste; 33% in 1980 a s compared with 30% in 1990.
|Dept of Environment, Transport & The Regions, 1997, Digest of Environmental Statistics No19|
|Institution of Civil Engineers, 1996, Environment File|
|Emap, 1997, New Civil Engineer 2/10/1997|
|Eblen & Eblen, 1994, Encyclopedia of the Environment|
|Melanby, 1992, Waste & Pollution - The Problem|
My thanks to:-
|Carol Taylor (Recycling Officer Lancaster CC)|
|Jane Hawkes (Waste Disposal Officer Lancashire CC|
|Ken Earnshaw (Site Manager, Lancashire Waste Services, Salt Ayre Waste Centre)|
|Institution of Civil Engineers Library|
Back to my university contents page
Back to my homepage