Aberdeenshire treatment plant grows to accept landfill leachate waste

Leachate waste from landfill sites can now be handled at Fraserburgh’s Waste Water Treatment Works (WWTW) in a bid to reduce carbon emissions.

Following investment by Scottish Water Horizons, the public utility’s commercial subsidiary, and site management company Grampian Water Services, landfill operators in the Northeast of Scotland can now send their leachate waste to a local facility for treatment before being safely returned to the environment.

The facility’s enhancement was a result of a collaborative effort between both companies and the Scottish Environment Protection Agency (SEPA). It resulted in the site gaining a new Waste Management Licence and tanker reception facility to provide a much-needed leachate outlet in the area.

Leachate treatment at Fraserburgh

Leachate, a liquid that is created when rainfall percolates through landfill waste, goes through a series of treatment stages to separate water and any solids present. 

The water element is eventually isolated in a large tank where it is balanced and returned to the waste water treatment process at a controlled rate.  This treated “liquor” is then discharged to the sea along with the rest of the site’s final effluent.

The remaining treated solids, which have now become “sludge”, are taken to another Scottish Water treatment works in Aberdeenshire, where they are thermally hydrolysed and digested.  Biogas is generated in this process to fuel the site steam boiler, as well as producing electricity via CHP (Combined Heat and Power) engines for use on site or exported to the National Grid.  The resulted treated biosolids are then recycled to agriculture, with significant nutrient benefits over commercial fertilisers.

A reduced carbon footprint

Prior to the site’s enhancement, landfill operators often had to transport leachate to the central belt and beyond for treatment. This resulted in higher transportation costs and carbon miles.

Scottish Water Horizons Sales and Contracts Manager, David Weber, said: “The Fraserburgh site was chosen as it has excellent vehicle access and spare treatment capacity. By introducing a local treatment option, landfill operators can now handle their leachate waste more efficiently whilst reducing the social and environmental costs of keeping fleets of tankers on the roads.”

It is estimated that recent modifications to the facility will help landfill operators reduce transportation by around 50,000 miles each year and save around 94 tonnes of CO2 annually. This is the equivalent of offsetting around 300,000 miles from the average passenger car.

Grampian Water Services Team Manager, Steven Frankl, said: “We’re delighted to accept this new waste stream to support Scotland’s wider decarbonisation efforts. The Northeast of Scotland has been lacking leachate treatment facilities for some time and we’re pleased to have an opportunity to provide a sustainable waste outlet.

“Throughout this process, we’ve also been mindful of reducing our own carbon footprint. We found ourselves in the fortunate position of being able to use a previously redundant tank and site logger which saved us from sourcing new materials.”

Increasing renewable energy generation

The Fraserburgh site also plays an important role in facilitating the generation of biogas.  Treated sludges are transferred to another treatment works in Aberdeenshire where they are transformed into biogas. This biogas can be used to provide heat and power for use on site or in the case of the electricity, surplus power can be exported to the National Grid.  

Steven says: “Recovering value from waste is one of our key strategic aims. By increasing waste volumes received at our sites such as distillery by-products and landfill leachate, we can boost biogas production. 

“Moreover, any additional electricity demand for treating importing waste is outweighed by the power that can be generated from it.”

The Aberdeenshire facility is also home to another Horizons sustainable investment – the installation of a solar photovoltaic (PV) scheme. It includes innovative bifacial solar panels which generate green energy and reduce emissions.

David said: “Land was also available near the site to enable the installation of photovoltaic panels. The panels will capture the daylight available to further generate electricity and reduce reliance on imported grid electricity. Critically, it also helps to manage the costs we charge operators as the panels will help to offset energy consumption at the site.”

A sustainable future  

The combined efforts of all parties have resulted in environmental wins all round. It is a perfect example of how public and private sectors can work together to develop sustainable solutions.

Steven concludes: “Considering the reduction of vehicle emissions, increased biogas generation and the provision of a sustainable and local waste outlet, the overall carbon footprint associated with treating landfill leachate is significantly reduced.

“Not only does it meet SEPA’s aim of providing local facilities, it also contributes to Scotland’s net zero emissions targets and zero waste ambitions.

There are currently three waste water treatment sites that accept landfill leachate which provide environmentally responsible treatment solutions across Scotland.