1.5 Current Waste Management Practice within the Western Isles

Future plans for the management of an area’s waste must be based on a sound understanding of its source, quantity and composition, and the existing transport and management infrastructure. The Western Isles has a relatively self-contained system for the management of household, commercial, and industrial wastes. However certain specific wastes, such as scrap metals, special wastes and some fish wastes, are exported for specialist treatment or disposal.

In common with the rest of Scotland, the Western Isles have traditionally relied on landfill as the primary method of waste disposal, and this is very much still the case. There are two strategically important landfill sites; Bennadrove near Stornoway, and Rueval on Benbecula. The capacity of the larger of the two, Bennadrove, at 40,000 tpa is expected to be sufficient beyond the 20-year period of this plan. Current estimates suggest that Rueval will be closed by 2007. Only in the last 2 years has CNES begun developing alternative waste management options such as recycling facilities.

1.5.1 MSW Management

The data in the following section were obtained from analysis of SEPA’s 2001/02 Local Authority Waste Arisings Survey (LAWAS) results, CNES landfill and recycling returns, and discussion amongst the WSAG members.

MSW Arisings and Trends
It is estimated that in 2001/2002 there were a total of around 40,300 tonnes of waste arising annually in the Western Isles. The approximate breakdown of this total by waste type is given in Figure 1.1 below. As the figure shows, an estimated 16,542 tonnes of the total were MSW, or around 41%. 14,169 tonnes of this is household waste, and the remaining 2,373 tonnes are from commercial premises.

Figure 1.1 – Estimated Baseline Waste Arisings by Source 2001/02

Source: CNES 2001, SEPA 2002

Based on current projections, the WSAG has assessed that there is likely to be only a slight increase in MSW arisings in the area over the next 20 years – around 5% in total, or an average of 0.25% each year. Although the population is forecasted to decline, the number of households is set to increase – from 11,670 in 2000 to an estimated 12,070 in 2014, a total rise of 3%. The last 3 years has seen an average annual increase in MSW
arisings of around 0.35%.

As the total tonnage of MSW arising in the area is relatively small, so too is its sensitivity to relatively small percent rates of growth (i.e. <1%). However, for reasons of prudence, the WSAG has agreed to assume an average annual MSW growth rate of 0.5% for the purposes of developing this plan and calculating waste diversion and recovery targets. Ongoing monitoring of MSW arisings will be carried out as part of tracking the plan’s implementation, and targets will be revised should any unexpected changes in MSW growth occur.

MSW Composition
The results of a recent analysis of the composition of household waste collected in the Western Isles are shown in Table 1.1. These studies, focused solely on kerbside household waste, were instigated by the local authority as a first step towards developing a detailed AWP Implementation Plan. MSW also includes substantial quantities of waste from commercial premises, skips, civic amenity sites and special collections. No up-to-date local data are available for the biodegradable content of these other wastes, although they are believed to contain a lower overall biodegradable fraction than kerbside household waste.

In the absence of reliable local data (for civic amenity and skip waste, commercial waste, and waste from special collections), it is assumed that the BMW content of total MSW in the Western Isles is around 60%. This figure, and those in Table 1.1 over have been used as the basis for developing all the targets in the AWP.

Table 1.1 - Baseline (2001/02) MSW management mix (tonnes per annum)

MSW Management Systems
The local authority, CNES collects and disposes of all the area’s MSW. Householders either purchase or lease a wheeled bin, and commercial customers lease wheeled containers or skips, although there are some uplifts of loose material on request. The council also provides an extensive ‘community skip’ service whereby skips are placed in suitable locations for householders to bring their waste for subsequent disposal. There are a small number of small-scale private waste operations collecting and landfilling inert construction and demolition waste.

Almost all the area’s MSW (>99%) is currently disposed of at the local authority’s two landfill sites – Bennadrove near Stornoway and Rueval on Benbecula. An estimated additional 1000 tonnes of waste (mainly scrap, clinical waste and other special wastes) are exported by ship to the mainland for reprocessing or safe disposal. Bennadrove is by far the larger of the two landfills and is the destination for over 80% of the area’s waste. There are also two privately operated inert landfill sites.

An estimated total of only 59.1 tonnes of municipal waste were recycled in 2001/02, although this figure does not include scrap cars and other metals, much of the waste material from which is in fact recycled.

However, a number of new initiatives are in the early stages of development in the islands to begin the required shift away from reliance on landfill disposal. Waste minimisation is currently promoted by CNES at community events and support for waste minimisation is also available through Western Isles Enterprise. A number of reuse schemes are currently in place that have important socio-economic and cultural value to the area, including
the following:

• Reclaimed wood and unwanted furniture are collected at Bennadrove landfill site for reuse locally
  

• A recent visit by a tyre baler to Benbecula has proved very successful, and the bales are being used as bunding in local landfill developments
  

• A project is in place to facilitate the salvage and reuse of local demolition stone in restoring community buildings
  

• Textiles are collected by the Blythswood charity (some rags are transported to the mainland for reprocessing) and other local charity shops accept used items.

A range of recycling services have recently been introduced to the Isles, primarily in the Stornoway area. These include the following:

• Drinks cans (aluminium and steel), mixed glass and plastic bottles are collected via 12 bring sites in Lewis/Harris. The majority are in the Stornoway area. Metals and plastic are exported for recycling. Glass is crushed and used locally as an aggregate replacement material (CNES is a registered packaging reprocessor with SEPA).
  

• Paper newsprint is collected at Bennadrove landfill site, then shredded and baled for local use as animal bedding. A pilot project collecting paper and cans also operates from one of Lewis’ community schools. The local market for animal bedding is limited, and some material has already been exported to Skye.
  

• Scrap cars are collected under contract, baled by CNES, and exported to the mainland.
  

• Oil is collected via bring sites located throughout the islands, then transported to Bennadrove landfill for dewatering, bulking and export to the mainland.

1.5.2 Non-MSW Management

In the Western Isles these wastes include industrial wastes, construction and demolition wastes, clinical wastes, special wastes and relatively small quantities of other wastes (e.g. oils, veterinary waste, abandoned vehicles, fridges, etc.). Agricultural wastes, although not current subject to regulatory control, are also extremely important.

Figure 1.2 – Baseline Non-MSW to Landfill

Source: CNES 2001

The majority of non-MSW is handled by CNES and disposed of at one of the two CNES landfill sites. Some local fish waste is currently disposed of by land-spreading and injection, and the majority of natural (i.e. organic) agricultural wastes are also spread on land.

Industrial Wastes
In purely quantitative terms, by far the most significant component of industrial waste in the Western Isles is fish-related waste (see Figure 1.2). Fish wastes are composed of two distinct waste streams associated with fish production (e.g. dead/contaminated fish or ‘morts’) and fish processing (sludges/slurries). There are other industrial wastes in the Isles, although research is required to identify their sources and quantities. There is a relatively small amount of offshore waste imported to the Isles (171 tonnes). Some industrial waste is exported off the island for safe treatment and disposal – e.g. fish waste ensiled and exported to Norway. The majority of industrial waste – around 4000 to 5000 tonnes per annum in total – is disposed of at the two main landfill sites. There are a small but increasing number of innovative projects to reuse or recover sector-specific wastes such as those from the fishing industry. A good example is the use of scallop shells to provide a material for drainage and construction.

Construction and Demolition Wastes
A substantial quantity of construction and demolition waste arises in the area (some of which is included as “other” wastes in Figure 1.2). A recent national SEPA research project into this type of waste suggested that some 12,487 tonnes arise annually in the Western Isles, of which the majority (circa 7250 tonnes) is exempt from waste management licensing. Of the remainder, roughly half is reused/recycled and the other half is landfilled.

Agricultural Waste
A small amount of agricultural waste is disposed of at local landfill sites. A more substantial quantity is disposed of to land on the many smallholdings and crofts throughout the isles. These wastes are likely to be brought under the regulatory control regime in late 2003, a development that has important implications for the farming industry (including crofters) in all the island areas. Current expectations are that initially only ‘non-natural’ farm wastes will be included in the first instance (e.g. plastics, metals, pesticide residues), although sludges/ slurries may also be covered if these wastes require transportation and disposal off-farm. Developments in this area will have a major impact on the non-MSW component of this plan.

Sewage Sludge
In 1999 Scottish Water introduced two interim treatment plants at Chivas Regal in Lewis and Market Stance in Benbecula to process and treat sewage sludge collected from both public and private septic tanks throughout the Western Isles. The raw sludge is treated by lime pasteurisation to produce a soil enhancing material for use in areas of Machair regeneration. The total production of raw cake was initially 180 tons at Chivas Regal and 50 tons at Market Stance per annum.

Although the first option for disposal of the enhanced treated sludge was to spread it to arable land, a scheme was devised where the sludge could be used to stabilise the machair where it was being eroded by wind blow. In December 2000 an application for grant aid from the European Regional Development fund was approved allowing this operation to proceed. Scottish Water have worked in partnership with SEPA, SNH, SAC and the local authority to pilot three schemes, one in Upper Barvas Machair in Lewis in 2000, one in Hosta in North Uist and a second scheme at Upper Barvas in 2001. The schemes have so far proved highly successful and the project has attained a Green Apple Award sponsored by the Chartered Institution of Environmental Health and the Institute of Waste Management.

In 2002 the Stornoway Waste Water Treatment works at Holm and another new facility at Market Stance were commissioned producing an estimated additional 980 tons and 160 tons of raw cake respectively. This considerable increase in the available treated material give the opportunity for the scheme to be expanded to also include non-machair applications for the first time. It is apparent from the results to date that there are clear benefits to the use of the biosolids in stabilising and re-instating the machair. This protects the integrity of the dune/coastal pasture system, and may help to reduce the impact of blowout erosion. It also provides much needed organic enrichment to the soils.

Non-MSW Trends
Predicting trends in non-MSW arisings is highly complex. As the islands undergo a shift away from the traditional industries towards new areas of economic activity, such as the development of renewable energy capacity, the mix of non-MSW streams will change. New challenges and opportunities will arise as a result. Although non-MSW arisings have been fairly constant during recent years, there is no guarantee this will continue to be the case. Identifying and quantifying trends in industrial and other non-MSW streams will need to be addressed as part of the ongoing development of the BPEO for these wastes. What is clear is that regulatory controls will tighten, and a number of current practices may change with major implications for the Isles. The most important development in the short term will be the amendment to waste management regulations that brings agricultural wastes within the regulatory regime.

1.5.3 Existing Waste-Management Facilities

The existing waste management infrastructure in the Western Isles is based on the two existing landfill sites. Tables 1.2 and 1.3 below summarise the type and capacity of waste management facilities currently in place.

Table 1.2 - Existing Landfill and Civic Amenity Site

Table 1.3 - Existing Waste Transfer, Sorting and Treatment Facilities