Water Supply
New options to consider for zebra mussel control By Rinita Banerjee
Z
ebra mussels were first discovered in Canada in 1988 and have become a well-established nuisance in the Great Lakes. Their rapid colonization rate and environmental resilience make them difficult to control. Zebra mussels can adhere to hard surfaces such as PVC, plastics and metal surfaces to form multilayer colonies (Griffiths et al, 1991). This results in blockage or reduced flow in pipes and water intake systems, leading to adverse long-term economic impacts. Various design techniques have been employed to control mussel infestation. The most common include a combination of chemical treatment and mechanical removal. However, concerns have been raised about the harmful effects on non-target aquatic species. continued overleaf...
Zebra mussel infestation results in blockage or reduced flow in pipes and water intake systems, leading to adverse long-term economic impacts. Photo courtesy Cottonwood County.
Technology
Advantage
Disadvantage
Usage
Chemical Oxidation
Widely used in the industry, readily available
Difficult to install and monitor, harmful to non-target aquatic species
Raw water intakes of Toronto’s water treatment plants and most GTA municipal lake based water supplies
Mechanical Removal
Simple and easy to administer, energy efficient
Labour intensive, must be repeated often to prevent buildup
Used extensively as a temporary fix
Thermal Treatment
High energy requirement
Causes damage to the ecosystem, must be repeated at least twice a year
Foul Release Coating
Different options available to suit site specific needs, long lasting
May be expensive, prone to corrosion and abrasion
Parker Dam Colorado- field test site
Low Frequency Magnetism
Highly effective, low maintenance requirements, not harmful to the lake ecosystem
Not readily available, needs electricity, expensive
US Steel Water Intake (Chicago) pilot test
Pulse Acoustics
High efficiency, not harmful to the lake ecosystem
Not readily available, needs electricity, expensive
Georgia-Pacific paper towel and tissue mill off the shore of Lake Champlain, NY- field test site
UV Light
Effective
Recommended for small systems, not efficient if water has high turbidity
Used in drinking water systems. Experimentally proven to kill zebra mussel veligers
Table 1. Different zebra mussel control technologies with their advantages and disadvantages. 66 | April 2016
Environmental Science & Engineering Magazine