Monday 22 December 2008

How to Do Your Landfill CQA Up to the Start of the Construction Works

How to Do Landfill CQA up to the start of the Construction Works, which the construction contractor will then be required to follow, and which will once completed be reported upon to the environmental regulator.

The end goal is for the environmental regulator to agree that the landfill has been designed to the required high quality standard of construction, and grant the waste management licence, effectively allowing the site to open and start accepting waste materials.

The Video Below Shows You a Landfill Which is Proposed Well Away from Habitation.



Each CQA programme is specific to the site and the detailed design adopted.

The monitoring and tests to be carried out during construction should be appropriate to the materials chosen, and be focussed on the essential requirements for ensuring compliance with the specification, primarily ensuring that re barrier is as low in permeability in use as intended when designed.

So, you should base the most detailed checking on the results of the HRA just as the liner design itself will have been chosen to comply with the degree of engineered containment required by the HRA.

So, now that we have explained how site-specific variations can be very important and may change the CQA plan a lot, we shall describe the requirements for a typical CQA programme, including provision of the detailed as-built drawings and CQA report.

The early involvement of the consideration of CQA and availability of materials/constructability within the design/build process is invaluable in ensuring that the installation of the design can be carried out without unnecessary difficulty.

The designer must check that construction can be achieved without compromising design requirements.

Construction must also be devised to a programme and working methods to include only those geosynthetic configurations which can be properly monitored within the CQA programme.

A review by the CQA engineer to verify that the design methods and construction techniques chosen can be properly constructed and adequately monitored.

The CQA engineer then prepares the CQA documentation.

A crucial element in the CQA programme which sets out requirements for both the materials and the workmanship involved in the liner construction.

Now that the material has been chosen and described, the documents must provide the minimum requirements for fabrication of the selected material into a liner, and the programme of checks must be stated by the engineer.

The key to a really good design will be the extent of close co-operation between the design engineer and the CQA engineer.

There should then be a CQA Construction start meeting. The idea of this meeting is that it can be a valuable opportunity for the design engineer, CQA engineer and geosynthetic installation contractor to verify that all parties have the same understanding of the specification.
Steve Evans has provided more leading information on Landfill CQA (landfill Construction Quality Assurance) at his blog. A full version of this article is available at How to Set Up a Landfill Construction Quality Assurance Plan.

Landfill What is Landfill

Landfill is when waste is dumped in landfill sites and buried, but a landfill is not where the waste is just tipped or dumped. At a landfill the waste infilling is controlled usually by a waste regulatory authority or environment agency, by a waste disposed license or permit. Landfill sites usually, if well regulated, do not cause pollution problems. On the other hand tips or dumps being uncontrolled usually do cause pollution.

Watch our VideoBelow - About the Interior of Landfill and the way a landfill is lined and built-up in cells



One of the problems with landfill is that space for landfill sites is running out. Landfill is popular because it is significantly less costly than other methods of disposal ? It should not, however, be regarded or perceived as a cheap and nasty option. There are substantial costs if landfilling is to be done well, but the results can be veru good, and even th best recycling still results, in the end in at least some waste, which is usually landfilled in a responsible manner.

Sites must be equipped so that dirt is not dispersed onto public roads and surrounding land. Any contaminated water and leachate must be collected and treated except where deemed unnecessary by the competent authority. Site specific environmental plans are developed as part of the planning process.

All plans for landfills must include statements establishing that the landfill operator will implement environmental monitoring systems on operational sites, continue this monitoring after site closoure, and only then cease these after a very many years when the environmental regulator agrees that environmental impacts from such cessation would be negligable.

Methane emitted by decaying waste is a major greenhouse gas, and although it disappears more rapidly from the atmosphere, it is around 20 times more potent a greenhouse gas than CO2.

Methane gas from landfills is collected, and often used to power a generator and produce electricity. This methane /landfill gas is delivered through pipes to the Waste-to-Energy plant where it is transformed to electricity.

By using the energy from waste there are serval advantages. Methane emissions contribute to climate change, but burning it to make energy greatly reduces the carbon dioxide global warming equvalent effect. Those using the energy from waste don't need to dig up more coal or oil/natural gas so it reduces demand for the fossiliferous fuels to be used.

Landfill sites are one of the biggest easily avoidable sources of methane, although operators are getting increasingly good at capturing the gas and burning it for energy. Methane is a green house gas and methane gas from landfills has been shown to be a major contributor to global warming and the green house effect. Under the European Landfill Directive and the Northern Ireland Landfill Allowances Scheme the Council must substantially reduce the amount of organic waste they send to landfill each up to the target year of 2010 or they could be facing potentially huge fines. Methane is also produced from the decomposition process, to ensure this does not accumulate within the landfill site this gas has to be flared.

Leachate exits the site via a number of pipes at the base of the landfill. The flows are collected and pumped into the Settlement Tank, which is divided into two compartments. Leachate is controlled to prevent it polluting underground water systems. Lastly, many of the manmade "disposable" products, such as nappies and plastic bags, can take several hundred years to rot away. Leachate is the liquid effluent resulting from infiltration of precipitation into a landfill. As precipitation percolates through the waste, leaching occurs involving the potential dissolution of compounds.

Landfill can create problems for local communities including nuisances from more traffic, noise, odours, smoke, dust, litter and pests.

Much more could be done to reduce and recycle the waste we produce and small changes can make a big difference. Recycling uses much less energy and raw materials than making new products. Please support recycling, and practise it yourself.
Steve Evans has provided more leading information on Landfill at his web site. Also we highly recommend the next closely related web site at Liners for Landfill.