Technology Innovation winner cleans up on domestic front

Alpha Environmental Systems won the prestigious Innovation Award for Technology at the ICU Exhibition 2005 held at the NEC in Birmingham in May,in recognition of the company's carrying out the first successful chemical oxidation remediation at a domestic property in the UK. At this particular site chemical oxidation was utilised as part of a multiple technology remediation strategy.

The award also recognised Alpha’s success in scaling down industry accepted remediation equipment and technologies to provide technical in-situ remediation solutions for domestic heating oil spills and similar scale projects. A range of multi-phase groundwater separation and treatment, vacuum, biological and oxidative equipment is now available for these types of projects.

The company utilised hydrogen peroxide when undertaking oxidative remediation at this site. The critical parameters for successful in-situ oxidation remediation revolve about subsurface distribution, off-gas pressure control and heat of reaction. The company has devised a close coupled liquid and air pressure injection system linked to vapour removal via sequential process application to probes inserted into the sub-strata.

This distribution and control process utilises the same probe assembly to perform injection, distribution control, pressure control and off-gas recovery for single point treatment. The benefit of this less complicated installation is reduced intrusive activities during the remediation system installation and minimised interconnecting pipework.

Specialised equipment to facilitate the above processes have been designed and manufactured in-house by Alpha. This ranges from units capable of operating upon hundreds of probes for larger contaminated plume areas to smaller items suitable for domestic applications. The equipment is all housed in a discrete, secure container.

Case study

In a case study cited by Alpha a multiple technology remediation strategy was adopted to remediate an oil spill around an existing domestic property located upon estuarine sands. In December 2003 the base of the ageing steel heating oil tank split due to frost damage and approximately 2,000 litres of fuel escaped directly into the subsoils. The contaminated soil plume was partially identified by a consultant to extend beneath the front garden, front bedroom and adjacent lounge.

A multiple technology remediation strategy included Vacuum Enhanced Free Phase Recovery (VEFPR) to simultaneously remove the free product, abstract contaminated groundwaters for ex-situ treatment and recover soil vapours from both the subsurface and the property. The groundwater dissolved phase target was reached within 16 weeks of VEFPR operation in combination with oxidative and bio-remedial techniques.

From first involvement with this site, Alpha reports that total clean-up was achieved within 20 weeks whilst allowing the householders to occupy the property for the majority of this period.

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