CASE STUDY

Bacterial Inoculants, Oxygen Release Compound

OVERVIEW

Introduction

Previously unidentified underground storage tanks

were uncovered at a former petrol filling station in

West Sussex, that was due to be redeveloped by

a major supermarket.

Detailed investigation encountered a plume of

hydrocarbons up to 29mg/l were recorded in the

groundwater. A local water body and the ground-

water in the chalk aquifer were found to be at risk

from the migrating plume.

Treatment Design

Geo2 worked with an Environmental Consultant to undertake the remediation, which employed a detailed Site Investigation and Risk Assessment process to calculate suitable Remediation Targets.

The treatment programme involved:

• Injecting a solution containing a bacterial agent together with a catalysing Oxygen Release Compound into the contaminated areas of the site.

• A total of 41 injection points were treated, preventing the need to remove any soils.

• After the treatment, the site was left for the developers to start work, whilst the remediation continued in the subsurface

Results A hydrocarbon concentration reduction of 97% was achieved. This was far higher than the client had experienced on previous projects (with other contractors) using similar techniques.

Avoided costly soil removal and disposal costs or costs and disruption associated with ex-situ treatment.

Remediation Specialists Experienced evaluation • Innovation solutions • Efficient implementation

Geo2 Remediation Ltd • 11 The Mending Rooms • Sunny Bank Mills • Farsley • Leeds • LS28 5UJ

www.geo2.co.uk • info@geo2.co.uk • 0113 257 5397

Hydrocarbons in Groundwater.

97% reduction Remedial Targets Achieved.

Bacterial Inoculants, Oxygen Release Compound.

1 week on-site.

Source

Treatment

Timescale

Result

“Working with developers who place significant demands on time and budgets, your reputation is on the line to an extent. I can honestly say however, that working with Geo² on this project has enhanced “our credentials in this market”.

Client Testimony

Bacterial Inoculants, Oxygen Release Compound

DETAILED EVALUATION

Method

Using direct push injection we delivered a bacterial inoculant solution, specially selected for hydrocarbon degradation, and a catalysing Ox-ygen Release Compound (ORC) at 41 injection points across the site, without needing to remove any soil for more costly ex-situ treatment.

Due to our experience in using similar methods at other sites and from our other research, Geo2 knew that the ORC would continue to work for up to twelve months. During this time, the ORC would help with the aerobic respiration of the in-digenous and introduced microbes.

Following the application, which was administered over the course of a week, Geo2 vacated the site which allowed the developers to get on with their work.

Results

The results of the treatment were impressive, amounting to a hydrocarbon reduction of 97%. The reductions achieved were greater than the client had experienced on previous projects using similar techniques. The results enabled our client to meet their deadline and deliver this aspect within budget.

Remediation Specialists Experienced evaluation • Innovation solutions • Efficient implementation

Geo2 Remediation Ltd • 11 The Mending Rooms • Sunny Bank Mills • Farsley • Leeds • LS28 5UJ

www.geo2.co.uk • info@geo2.co.uk • 0113 257 5397

Introduction

Geo2 were brought in as remediation experts following the discovery of extensive hydrocarbon impact at a former car and petrol retailing site in West Sussex. Environmental Consultants had already undertaken an extensive investigation and Quantitative Risk Assessment in order to establish which contaminants required treating and the concentrations that needed to be achieved to fulfil the planning conditions.

Hydrocarbon Impact

Following site closure and removal of the remaining structures on site more thorough investigation of the soil and groundwater was able to be undertaken. At this point, two further underground tanks were found that did not appear on historical records, putting the local water body and wider water table at risk of contamination.

Following a process of competitive tendering, Geo² were selected for the remediation contract because of the ‘practical and proficient approach’. Our approach provided the answers the client needed quickly and confidently pinpointing a treatment meth-od that would deliver the required results within their client’s fixed redevelopment window.

Both the Client and developer “We were particularly impressed by Geo²’s attention to detail in producing a remediation method state-ment that far exceeded its remit, making our dialogue with the Environment Agency far more straightforward and efficient.” Client Testimony