Dimmer Landfill Site

Dimmer Landfill Site
Site Location See Non-Hazardous Landfill → page for a wider UK perspective.
Waste Licence	UP3139BB (UP3139BB)
Operator	Valencia Waste

Void

Year	Total Void
2018	745494
2019	603931

Summary site information collated from a variety of sources
including: Monksleigh, Ellard Associates, EA, WasteDataFlow,
SEPA, NRW, DEFRA, BEIS and owner and developer websites

Summary

Dimmer Landfill Site was developed from 1970 onwards, initially by Wincanton Rural District Council and then from 1974 onwards by Somerset County Council. The Landfill site came to be operated by Viridor following the sale of Wyvern Waste Services Limited to Viridor in 2006. Dimmer was one of two operational sites that passed to Viridor at that time. The most recent parts of the site are operated to Landfill Directive compliant standards.

It is understood that some of the permitted capacity may not be filled for commercial reasons.

History

Dimmer landfill was opened in 1970 by Wincanton Rural District Council. In 1974, following local government re-organisation, control was passed to Somerset County Council and was operated directly by them until responsibility was passed to Wyvern Waste Services Limited (WWS). WWS was a LAWDC (Local Authority Waste Disposal Company) formed by Somerset County Council in 1991; the assets at Dimmer were passed to WWS in 1992.

Somerset County Council sold its LAWDC to Viridor in 2006, the company name subsequently changing to Viridor Waste (Somerset) Limited in June 2006.

Some of the land used by the site was previously used as a ordnance dump during the second world war by the US military; very limited evidence of the former use is still visible on the site. Otherwise the land occupied by the site has historically been agricultural land.

The site is comprised of two principal parts - the original site and the extension area, but to all intents and purposes, the two sites are operated as one site. The site is a landraise (rather than a landfill) being constructed above original ground levels with no mineral extraction for off-site sale.

The Waste Management Licence was changed to an Environmental Permit in 2003/4 as required by the changing legislation at the time.

There have been several planning permissions for the site since 1970, none of which imposed an end-date to landfilling operations. In 2015, Viridor sought planning permission to construct and operate a waste transfer station at the site which was intended to divert wastes to non-landfill final disposal, notably energy-from-waste in Avonmouth and Oxfordshire. This proposal received approval in 2015 as permission 15/00372/CPO. The application documents stated that the landfill would close prematurely in 2016 and that a separate planning application would be made to alter the approved restoration contours/Landfill Settlement Contours of the landfill to take account of this. To date, no such application has been listed on Somerset County Council's planning portal..

Geology

The site is underlain by interbedded mudstone and limestone of the Langport Member, which is of late Triassic and early Jurassic age and forms part of what is known as the Blue Lias. Excavations and site investigation at the site suggest that locally this largely comprises low-permeability lithologies.

Engineering and Environmental Control

The Landfill is constructed as a Containment Facility, utilizing the underlying clay materials as the principal barrier. In the most recently constructed parts of the site, the landfill lining system is augmented with a flexible membrane liner of High Density Polyethylene (HDPE) on the base. As the site is a land-raise rather than a landfill, there are no sidewall barriers. In cross-section the site is lens-shaped: the base is an approximate mirror of the upper surface

There is Landfill Gas power generation with electricity export to the National Grid. Installed capacity is 2.96MW

Viridor have been unable to secure a connection to the local sewerage system, principally due to a lack of local treatment capacity at the receiving Sewage Treatment Works. There is an on-site leachate treatment plant that discharges to a local watercourse. Dry weather flow in the receiving watercourse is low and consequently, the standards required to be achieved to discharge are sometimes difficult to achieve. Viridor have installed tertiary treatment via reedbeds and other growing media in order to permit discharge at times of dry weather. Occasionally, leachate produced by the site is removed by tanker to appropriately permitted Sewage Treatment Works..

Other Infrastructure

Elsewhere within the site complex, Viridor also developed a Composting facility and an [In-vessel Composting]] (IVC) facility to deal with some of Somerset County Council's separately collected Green Waste and some Food Waste. This facility is no longer in operation and has been converted to be used as a Waste Transfer Station. Whilst a planning consent was granted for an Anaerobic Digestion facility this was not built, with this infrastructure being built at Walpole Recovery Facility and Landfill Site instead.

Waste Tonnage, EWC List

The table shows a list of the Waste for the Permit UP3139BB, that has arrived into sites as reported to the Regulator and then publicised in their reported statistics. The Data was last updated in October 2023. The total reported tonnage arriving at the site was: 22,662t.

EWC Code	Description	Tonnes In
17 05 04	soil and stones other than those mentioned in 17 05 03	22662.00