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Waterloo Emitter
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Waterloo Emitter Diffusion Technology
The Waterloo Emitter is a simple, low cost device designed for the controlled release of oxygen or other amendments, to encourage and sustain the growth of micro organisms required for in-situ bioremediation of contaminated groundwater. The patented technology* enables direct diffusion into an aquifer of fluids (gas or liquid) through silicone or LDPE tubing which is wrapped around a frame. The frame allows insertion of sampling or monitoring devices for down-hole monitoring of groundwater conditions and remediation performance. Ideal for the bioremediation of BTEX and MTBE using oxygen and diffusion. The diffusive process provides immediate bioavailability of molecular oxygen for aerobic biodegradation enhancement, with no loss of amendment gas due to 'bubbling'. The Waterloo Emitter can also enhance desirable abiotic reactions (pH adjustment, hydrolysis, etc.).
Product Description
Applications
Oxygen release for aerobic bioremediation of BTEX and MTBE
Hydrogen release for anaerobic reductive dechlorination of solvents
Introduction of dissolved SF6, argon, etc for use as tracers
Release of CO2 for pH adjustment
Light alkane release to promote co-metabolic biodegradation of MTBE
Horizontal wells
Simple Flexible System
Waterloo Emitters are available to fit 2", 4" and 8" (50 mm, 100 mm and 200 mm) wells. They can be installed in cased wells or open boreholes.
1.8", 3.8", and 6" Waterloo Emitters Advantages/Benefits
Low cost
Controlled, uniform release for constant microbial activity
No amendment loss due to ‘bubbling
Easy installation and removal
No cleanup required on decommissioning
Very low operating and maintenance costs
No electricity required
No slurry to mix, handle or inject
No hazardous materials to ship or handle
Suitable for many forms of remediation
A series of Emitters can be stacked in a single well to ensure coverage of the full thickness of the contaminant plume. They can be used in conjunction with packers and/or circulating pumps to focus the diffusive release, or to increase the radius of influence. Emitters can also be connected from one well to another to allow easy management of the gas supply.
Almost any appropriate fluid (gas or liquid) can be used with the Waterloo Emitter diffusion technology, to apply specific chemicals to a contaminated groundwater plume for enhanced bioremediation, abiotic reactions such as pH adjustment, or for tracer tests.
The new 1.8" (46 mm) Emitters fit easily into existing 2" (50 mm) monitoring wells. For shallow applications in suitable soils, they can be installed through larger direct push casing, resulting in the lowest cost installation of any bioremediation enhancement device.
Operating Principles
The Waterloo Emitter consists of silicone or polyethylene tubing coiled around a PVC frame. When a fluid is introduced into the tubing, a concentration gradient is created between the inside of the tubing and the groundwater.
The Emitter works in accordance with Fick's Law, whereby diffusion will occur until there is equilibration in chemical concentration inside and outside of the tubing. With the Emitter technology, the oxygen (or other amendment) is replenished regularly, and the groundwater flow around the Emitter is continuous, hence an equilibration point is never reached. This results in a continuous flow, through diffusion, being maintained from inside the Emitter to the groundwater.
When a gas is applied to the Emitter there is a direct correlation between an increase in applied pressure and an increase in the amount of gas that will diffuse into the groundwater.
Installation
The 51" (130 cm) long Waterloo Emitters can be installed singly or placed in line one on top of the another. These stacked Emitters can be designed to ensure that the full thickness of the contaminant plume will receive the bioremediation enhancement.
If an enhancement gas is to be used for remediation, a small to medium sized gas cylinder can be used. Emitter tubing is selected and pressure is set according to the amount of enhancement gas required. A single gas cylinder can be used to supply multiple Emitters connected in series.
Replenishment of the gas inside the Emitter tubing can be accommodated by periodic purging (weekly/bi-weekly), or a needle bleed valve can be used at the end of the system to allow slow, constant replenishment to occur.