Why undertake remediation feasibility testing?
Under some circumstances it is beneficial to carry out a pilot trial before full-scale remediation is undertaken. This can give useful information to ensure that remediation is conducted efficiently to meet the client’s needs, budget and timescales.
Our in-house laboratory facilities are available for carrying out various tests, the results of which can be used to assess the preferred treatment solution, expected treatment times and associated costs.
Biodegradation laboratory trials are undertaken on samples of soil and groundwater. Accelerated tests can be undertaken in a matter of a few weeks, to derive useful information on bioremediation potential and likely timescales to reach specified target contaminant concentrations.
We also carry out laboratory pilot trials for the treatment of landfill leachate, which is often contaminated with high levels of ammonia, petroleum hydrocarbons, volatile fatty acids and metals. An example project report for a laboratory leachate treatment pilot trial is available to download.
Field pilot trials and pumping tests
Pilot trials can be undertaken to demonstrate the effectiveness of a remediation technique prior to full scale implementation. Typical trials may include the following:
- Ex-situ bioremediation - screened soil is characterised, sampled, analysed, blended with suitable amendments and formed into a biopile. Samples may be taken weekly for chemical testing. A typical timescale for an ex-situbioremediation trial would be 8 to 16 weeks.
- In-situ bioremediation - this can be either aerobic or anaerobic. For example, in-situ treatment of groundwater contaminated with chlorinated solvents could involve injection of a hydrogen release substrate to promote anaerobic biodegradation. This could be applied to a small test area within the plume source, or as a limited permeable reactive barrier arrangement. Further details of an in-situ bioremediation pilot trial are available to download.
- Air sparging - air is injected into the saturated zone by connecting mobile equipment to previously installed test boreholes. The effect on the water table is monitored including extent of mounding, radius of influence, rate of contaminant removal, effect on dissolved oxygen levels.
- Soil vapour extraction (SVE) - mobile testing equipment is mobilised to site, connected to test boreholes, and used to determine parameters such as radius of influence under various vacuum pressures and flow rates, and rate of removal of contamination in kg/h.
- Groundwater / free product pumping tests - these are undertaken to determine various parameters such as ground permeability, drawdown, rate of recovery and free product yield.
- Landfill leachate treatment field pilot trial - leachate is pumped to above ground equipment where the treatment process can be monitored and optimised. Design parameters can then be used to scale up the system to full scale. An example leachate treatment case study is available for viewing.