Waste Management and Waste Accetance Criteria (WAC)

Site Investigation

SITE WASTE MANAGEMENT PLANS (SWMPs)

In England, the SWMP Regulations 2008 came into force on 6th April 2008.  They apply to ‘construction projects’, and to the whole life of a construction project, from design all the way through to completion.  As well as including actual construction works, they include renovation projects, site preparation works, the installation of services, and all kinds of demolition.  If you carry out a construction project where the value of the materials plus labour exceeds £300,000, it becomes a criminal offence (for both the project manager and the main contractor) not to produce a SWMP. 

The Plans must include basic elements like who prepared it, who’s in charge of the project, who’s the main contractor, what’s the location, and what’s the estimated value.  But it must also include details of the decisions taken at the outset on (1) the design of the project, (2) the methods employed and (3) the materials employed in order to MINIMISE the quantity of waste produced on site.  It will therefore be crucial to have evidence of that thought process.  The SWMP must describe each type of waste that will be produced, and estimate the volume.  Then, you must identify the particular waste management ‘action’ that will apply to the waste.  Is it to be dumped, sent for recycling, or perhaps recovered through use for land treatment under an exemption?

WASTE MANAGEMENT LICENSING

The Environment Agency has set out guidance as to the classification of waste arising from construction sites in its document “The Definition of Waste” dated April 2006.  This document outlines how waste is to be handled. 

The following activities are not regarded as a waste management activity requiring licensing.

Construction activities carried out for the purpose of producing a suitably engineered soil e.g. lime stabilisation, vibro-replacement and piling. 

Uncontaminated materials produced on site (including excavated soils and materials from demolition) which can be reused without further treatment.  Examples include site regrading and footing excavations.

These must be done in accordance with the Planning Permission.  Demolition material must be used in accordance with the quality protocols for the production of aggregates from inert waste, subject to appropriate testing and the lack of any harmful constituents.  Uses include pipe bedding, backfill and sub-base. 

Contaminated soils can be moved on-site providing they do not require treatment or containment.  There should be no risk to the environment i.e. non-leachable and in accordance with Planning Permission.  Relevant activities can include site regrading and use of materials below clean cover systems, capping, buildings and hardstanding. 

Where contaminated materials have to be placed in an engineered cell to prevent pollution, then this would be classed as landfilling and require PPC permits.  Any material taken off site is considered to be waste.  However, this is under review.  If material is waste, then there is a duty of care including ensuring material is transported by a registered carrier.  The destination of material leaving the site should be regularly checked and Waste Transfer Notes kept.

GAS MONITORING 

In March 2007, the NHBC issued a report entitled “Guidance on Evaluation of Development Proposals on Sites Where Methane and Carbon Dioxide are Present”. 

The document recommends that a Conceptual Site Model is produced at the desk study stage.  This can be used to produce a Preliminary Risk Assessment (PRA), with a view to assessing whether a ground gas investigation is necessary.  The NHBC guidance suggests that the production of a PRA is a preliminary tool only and “cannot remove the need entirely for ground gas monitoring data ..”.  This suggests that gas monitoring is needed in all circumstances.  This would normally comprise the use of gas monitoring wells over a suitable time period in order to establish maximum gas concentrations and flow rates. 

Our view is that if there is no evidence of any gas producing source and if spike testing or on-site testing shows no evidence of landfill gases, then we regard the risk of hazardous gas production to be minimal such that further on-going monitoring would not be required.  This is in line with the concept of there being no significant risk of significant harm i.e. no contamination.  If there is any element of doubt, basic gas protection measures can be installed at minimal cost and each site dealt with individually.

 

Waste Acceptance Criteria (WAC)

The main objective of the Landfill Directive is to prevent or reduce as far as possible the negative effects of landfilling waste on the environment and on human health.  It is intended to reduce the disposal of waste materials to landfills and to encourage more sustainable approaches to dealing with wastes.  It bans the landfill of liquids and certain solid wastes, introduces requirements for the treatment of wastes prior to landfill and provides for the classification of landfills as sites for inert, hazardous or non-hazardous waste and prohibits co-disposal. 

It sets out procedures for waste acceptance at landfills and the types of waste for each class of landfill as specified by Waste Acceptance Criteria (WAC).  The WAC are predominantly lists of “limit values” for certain parameters obtained from standard leaching tests of wastes going to landfills.  WAC are set out in the Landfill Directive itself.  Full details can be found in the Environment Agency document “Guidance for waste destined for disposal in landfills” Version 2 June 2006.