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Another example of a successful Enviros compost facility design service project:
Deerdykes Composting Facility Stage 1, Cumbernauld, Scotland
Conversion of a Sewage Works into a Composting Plant
A sewage treatment works standing idle since 2003 has been converted by Scottish Water Waste Services {SWWS) into a composting plant, by the Enviros Compost Team. It might seem an unlikely transformation, but the Deerdykes Composting Plant, which has been taking green waste from three local authorities, has attracted a grant of approximately £600,000 from the Waste and Resources Action Programme (WRAP) Organics Capital Support Programme through funding provided by the Scottish Executive and has entered its second six months of operation. It has already produced compost - the first 500 tonnes of which have been delivered to a local land restoration scheme.
Deerdykes STW was built in the 1970s and was originally known as the Cumbernauld Sewage Purification Works. The Kelvin Valley Sewer now serves the area, taking sewage past the site to a much larger and more modern plant downstream.
Clearly reuse - where possible - is the most sustainable option for redundant civil engineering structures. Enviros Consulting recommended reusing the works with very few provisos. The condition of the concrete was found to be very good, and the already extensive drainage system needed little more than a thorough clean.
The structures of the original activated sludge process plant are, to varying degrees, being recycled. Its rectangular sedimentation tanks will make excellent compost tunnels with their end walls demolished and a central dividing wall installed, while the activated sludge aerated tanks, with central division walls and near ends demolished, have become an organic waste reception area. One of the two circular clarifier tanks has been used to store sludge press washwater; an access ramp has been added and, in addition, demolition materials were crushed on site and used in the formation of new slabs constructed for the maturation of compost.
At present, the plant operates on the open windrowing principle. However, plans are well advanced for further investment by SWWS for the final stage of conversion: to add roofing to the tanks and install a controlled aeration system to create an in-vessel composting facility. This has been designed by Enviros Consulting to accept industrial sludges, green waste and liquid wastes. It will, at a later stage, be updated to take food waste. Liquid wastes will be stored on site and discharged to sewer. The sludges will be pressed with the resulting cake co-composted with green waste in the converted composting tunnels. Some green waste will also be composted separately in open windrows.
The production of premium quality compost from a wide range of organic waste materials requires a highly controlled in-vessel environment. Deerdykes plans to use a forced-air, in-vessel process providing an initial sanitisation and stabilisation process over a two-week composting period. This will be similar to the existing system already in place at the Beddington composting plant in Surrey and will use blowers and fans to circulate oxygen through pipes into the composting tunnels, while a series of probes set within the composting mass monitors the temperature. The stale air from the composting tunnels will be passed through a biofilter into the atmosphere. Once this in-vessel aerated static pile composting system has been completed, the site will be ready to accept a much wider range of organic waste materials for composting.
See also Beddington Compost Facility, also an Enviros Consulting, Design Service project.
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Deerdykes Composting Facility Stage 2, Cumbernauld, Scotland
The second stage comprised the construction of the in-vessel tunnels to provide a facility for accepting and processing pressed sludge cake and ABP. 
Enviros' bespoke design comprises 4 concrete composting tunnels, fully equipped with computer controlled in-floor aeration system. All blowers, ancillary equipment and even the biofilter are placed on the roof of the tunnels to save space and allow future site expansion.
Scottish Water Waste Services' first composting site is now operational and is expected to take up to 45,000 tonnes per year of green waste and various wastes from industrial and commercial customers. . SWWS has achieved PAS100 accreditation and the product is being marketed under the brand name 'Pod', SWWS is now in the process of obtaining ABPR approval to allow the composting of catering waste.
This is another important building block in the development of Enviros' composting facility design-and-build business, and will provide the foundations for developing an excellent market image for future prospects.
Two Enviros designed in-vessel composting facilities have been built in the UK; both constructed by Ascot Environmental. From this success, Enviros and Ascot are developing a partnership to offer the UK waste industry a new supplier of bespoke composting facility design-and-build services.
The Enviros-Ascot partnership offers a complete bespoke composting facility development package, including: design-and-build, conceptual design, technology options evaluation, economic feasibility studies, planning and licensing, training, and compost product market development.
It is hoped that this will continue to grow and expand, offering other forms of waste treatment infrastructure. Enviros and Ascot are now developing a new offering for the design and build of dedicated Gasification plants.
Click here to use our contact form to request further information on our design service.
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