GovWire

Construction quality assurance (CQA)

Environment Agency

January 17
08:30 2024

You must have construction quality assurance (CQA) for the construction of all aspects of landfill engineering and infrastructure.

Landfill engineering

Landfill engineering includes:

  • permanent geophysical leak location system
  • leak detection layer
  • groundwater underdrainage system
  • sub-grade or formation layer
  • barriers
  • liners
  • liner protection
  • leachate collection system
  • leachate abstraction system
  • separation bund or layer
  • cell or area surface water drainage system
  • side wall subgrade or formation layer
  • sidewall containment and leachate collection systems

Landfill infrastructure

Landfill infrastructure includes:

  • permanent capping
  • temporary capping such as engineered temporary caps, not cover materials
  • leachate abstraction systems
  • leachate transfer, treatment and storage systems
  • surface water drainage systems
  • leachate monitoring wells
  • groundwater monitoring boreholes
  • landfill gas monitoring boreholes
  • landfill gas management systems including gas extraction wells, gas collection pipework and condensate management systems
  • lining within the installation

Construction quality assurance (CQA) plan

You must have a CQA plan. This is a written management system for any construction you propose.

What to include in your CQA plan

Your CQA plan must include the following information that is relevant to your site:

  • a detailed design description with reference to existing stability assessments
  • drawings of your proposed landfill engineering or infrastructure
  • specification of the proposed materials you will use to construct the landfill engineering or infrastructure including the type and frequency of conformance testing
  • pass or fail criteria for all the materials you will use to construct the landfill engineering or infrastructure
  • details of the conformance testing you will carry out
  • how you will install each layer
  • CQA procedures for each layer
  • the procedure for agreeing changes to the design
  • details of the measures you will take where any non-compliance with the specification is identified for each material you will use
  • details of the information you will include in the validation report

Your detailed design description must consider scenarios during and after construction, as well as after completing the filling and capping of the cell. If the design differs to that supported by a previously agreed stability assessment, you must provide a further stability assessment.

Where you need to carry out testing, you must use an independent laboratory that has United Kingdom Accreditation Service (UKAS) accreditation for each of the tests proposed.

All drawings, maps or plans must be to a recognised scale and all units must be metric. Each drawing should have a label that includes:

  • title of the drawing
  • installation name
  • name and address of the operator
  • date the drawing was made
  • drawing identification number
  • scale of the drawing
  • key
  • National Grid lines and north point
  • paper size of original drawing

The drawings of your proposed landfill engineering or infrastructure must, where applicable, show:

  • existing topography
  • location of proposed cell or capping works, including location of adjacent cells or caps
  • cell formation level, including under drainage system
  • level to top of geological barrier
  • level to top of leachate drainage and collection system
  • layout of leachate drainage and collection system
  • location of leachate collection, extraction and monitoring infrastructure, including the location of all target pads
  • location of gas collection and monitoring infrastructure
  • cross section of the cell lining system or infrastructure, including anchor trenches and under drainage system
  • cross section of cell perimeter and inter bund design, including connection with adjacent and existing cells
  • cross section of leachate extraction infrastructure and basal and sidewall pipework
  • cross section of leachate monitoring chamber
  • proposed waste thicknesses

You must record all levels in mAOD (metres above ordnance datum).

Submit your plan

You must submit your CQA plan to the Environment Agency. You must not begin constructing any new part of the landfill or landfill infrastructure until the Environment Agency has confirmed its satisfied with your proposals.

You must submit CQA plans sufficiently in advance of the programmed work to allow the Environment Agency to consider your proposals

The CQA plan must be signed by someone with a minimum route A qualification for a CQA engineer.

You or your CQA engineer or inspector must notify the Environment Agency of non-conformances against the approved CQA plan.

Environment Agency staff will visit the site during construction to monitor how you implement the CQA plan.

Update on progress and agree changes to your plan

Your CQA engineer or inspector must provide a progress update to your local Environment Agency office. They must normally do this weekly. Include:

  • progress in the last week
  • the proposed work programme for the following week
  • weather conditions
  • in the case of multiple clay sources, the sources currently in use
  • any testing carried out, with results recorded on the appropriate forms as listed in the CQA plan
  • any problems with proposed or agreed solutions

If the next and subsequent cells are the same design, you only need to submit a new cell layout drawing to the Environment Agency before construction. The Environment Agency will need to confirm its satisfied with the cell layout drawing and that it does not need any more information.

You must agree any change to the approved design in writing with the Environment Agency.

CQA personnel qualifications and experience

You must use competent people and resources in all aspects of your landfill engineering and infrastructure works. For example, use a competent contractor, who has experience of working with the materials you propose in your design, to carry out the works.

You must:

  • provide the Environment Agency with the CVs of all office and site based CQA personnel involved in the construction works, for agreement, before the works begin
  • outline the roles and responsibilities of each member of the CQA team within a CQA plan for the works

The Environment Agency will base its agreement on the following:

  • qualifications and experience of the proposed CQA inspector
  • evidence of continued suitability
  • complexity of the proposed works

Where, during the works, there is evidence of poor performance, the Environment Agency may remove their agreement.

You must provide the CVs of all office and site-based personnel involved in the construction works to your local Environment Agency officer a minimum of 5 working days before the start of the works. You must confirm what role they will perform.

You must make sure that each CV includes:

  • the name of the person
  • their proposed role
  • their education and qualifications
  • their site specific experience, including the:

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