Oh DSEAR.....!
The minefield of legislation and buerocracy that is required to implement and operate a landfill site requires many of us to be a lawyer first and landfill engineer second! However these days Health and Safety legislation extends beyond simply wearing a hi vis vest and a hard hat. The introduction of the DSEAR Regulations has wide reaching consequences for Landfill Operators and Contractors working on the site. The most relevant section of the various ICOP's specific to our operation is covered in ICOP 5 and identifies the risks specific to the equipment used. Our method statements and risk assessments have applied the necessary measures to ensure the safety of the workforce. Whilst all legislation has a place, the extent of measures required and the subsequent financial burden that this has could affect large and small companies alike. Landfill sites now take a narrower range of waste types, unless it is a designated Hazardous site - of which there are few - and our boots and clothing now have to be anti-static. This raises issues about the school visits, local liaison visits, are we to remove all mobiles from visitors? With no requirement to supply non-employees with appropriate PPE or work clothing, accessible areas will be reduced to these personnel. This may fuel the fire even further with some individuals that landfill sites are dangerous places!?!
Return to topClay Wells
Historically, older landfill sites have less accurate site information available with regards to the basal levels, containment type and well constructions.
herefore preservation of these is preferable to retrodrilling as this may not always provide hydraulic continuity with basal leachate due to the inherent inaccuracies. Situations arise where the debris located within the wells is not silt or sludge. Material like clay and concrete pieces, which is not in a pumpable form, has to have its state altered to enable remediation works to commence. In a particular instance the clay was present to a depth of up to 6m and was heavily compacted as it had been located there for a number of years. The method applied for this case involved emulsification of the clay and applying suction at the same time. A specialised adapter has been manufactured to use in scenarios such as this to reduce the amount of bagging that requires to be placed down the well. This obviously assists with smaller well diameters. The 6m of clay was successfully removed from the bottom of the well. In addition to the clay there were house bricks, concrete biscuits and telephones! How and why the materials are located within the well may possibly be the World's Eight Wonder (although I am sure that there are endless plausible theories). What is important is that the well became functional again without damaging any of the existing fragile engineering. This well was then relined, by others, with HDPE pipework and the leachate extraction system reconnected. Completion of our operation on this particular well took less than 2 days.
Return to topLarge or Small
Compliance issues on landfill sites are extensive and operators have to ensure that all infrastructure is able to function as expected. The non homogenous nature of the materials involved and the sometimes dubious application of structural engineering to a wall of waste does give rise to temporary non functioning and sometimes complete failure. Nowadays the technology used to construct wells provides a greater degree of reliability. Although access through smaller diameters creates more difficulties to remediate in the event of a severe failure. Typically leachate well failures, in our experience, can be attributed to poor construction and particularly poor surround. Retrodrilled gas well failure appears to fail at relatively shallow depths, which in most instances appears to be due to rapid settlement of the restoration soils and the moment of heavy machinery around those areas. Well diameters and access requirements to these should be carefully identified for new cells. Smaller diameter wells make remediaiton more complicated and costly and any compliant leachate levels are achieved quicker. Ideally provision should be made in these wells to provide permanent acces for the hoses associated with the extraction system whilst allowing for remedaition works without ceasing any pumping. Other factors being investigated by the EA currently is access to basal leachate drainage via the vertical wells. This is unlikely ever to work efficiently due to the nature of materials and benfits that could be achieved are negligible. Although as with all cases studies one off applications may sometimes be appropriate.
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