Inverness Project

Shore Energy is planning to build a waste sorting and recycling centre on a site at Longman Drive within property owned by the Inverness Harbour Trust.

Currently, the majority of waste generated in the Highlands Region is transported long distances to landfill. This has to change for a number of reasons

• Firstly, the rules set by the EU and by the Scottish Government dictate that we have to reduce the tonnages of waste sent to landfill. Landfills produce methane which is a very damaging greenhouse gas. There are specific dates set for these changes and the Scottish Government has stated its intention to ban some materials from landfill by 2015.
• Secondly, more material has to be recycled; the Scottish government has set a target of 70% recycling by 2025 and whilst the Highland region has improved its municipal waste recycling performance, it is currently at 35%, exactly half the ultimate target.
• Thirdly cost, not only is the cost of moving the region’s waste to far away landfills expensive, but landfill tax is rising by £8/year. Since just over 100,000te of municipal waste goes to landfill, this means that the cost to your region rises by £800,000 every year. Unless something is done, this tax effect will continue, until in 2014 the tax bill alone will be £8,000,000 if nothing changes.
• Finally the Scottish Government Zero Waste Plan requires that commercial and industrial waste meets the same levels of performance – high recycling and low landfill.

In other words change has to take place and so facilities are required to achieve that change.

The site at Longman Drive has been selected for two main reasons; firstly, whilst the location is central it is clearly industrial and most of the area’s waste is delivered there at the moment, before being transferred out of the region. Secondly, it would be our intention to send the products from our process out of the area by ship, thereby removing many large waste carrying vehicles from the main arterial roads out of Inverness.

What is proposed?

The facility will contain mechanical equipment which is designed to facilitate separation of the waste into individual components which can then be taken to reprocessors for recycling. By using this technique, metals, plastics, glass, grit, stones and the like can be separated and a biomass fibre left. The biomass fibre can then be used to generate renewable energy (the Scottish Government also has a target to generate 80% of its energy from renewable sources by 2020) or to make renewable fuels such as biodiesel or bio-ethanol. The latter solution would help meet targets for renewable transport fuels set by the EU.

The process proposed at Inverness has three simple stages all of which take place inside buildings; firstly waste is received and an initial visual sort allows miscellaneous bulky or dangerous articles such as concrete blocks, tree stumps and gas bottles to be removed. Then the balance of the waste moves to stage two of the process, the autoclave. The autoclave is a rotating vessel which is filled with waste and then sealed, at which point steam is injected at about 160°C and 5bar pressure. This steam processing takes about two hours and has a number of benefits;

•    The bulk of the waste is reduced by up to 80%
•    The biomass in the waste, which includes cardboard, paper, foodwaste, garden waste and the like, is broken down into a sterile homogenous fibre
•    Metals are cleaned, labels and the contents removed
•    Plastic shrinks making it denser and therefore more easily separable from the fibre.

The steam is just clean water with no additives and once the process is finished, that water is cleaned and recycled within the process. The steam is generated using a conventional gas boiler – no waste is used as fuel.

The final stage of the process is mechanical separation; ferrous metals are separated using magnets, non ferrous metal using eddy current separators, plastics using optical sorters and glass and other inert material using density separation. All standard and well known equipment.

Once completed the separated fractions are baled and stored until an economic load is available to send the material to reprocessors.

The plant capacity will be around 120,000 tonnes of waste per annum and the plant will be available to the local Authority and commercial users alike. Once commissioned, the facility will offer an economic modern solution in compliance with national targets and with a big beneficial impact on the carbon footprint of the region.