POTASSIUM DOSING SYSTEM FOR CONTROL OF ZEBRA MUSSELS IN SEMI-STATIC WATER SYSTEMS

OCETA logo OCETA ENVIRONMENTAL TECHNOLOGY PROFILES

CAT. #03-020 / 08-017

CONTACT:
ASI Group Ltd.
250 Martindale Rd, PO Box 2205
St. Catharines, Ontario,
Canada, L2R 7R8
Tel. (905) 641-0941
Fax. (905) 641-1825 blaurens@asi-group.com www.asi-group.com

PROCESS/ PRODUCT DESCRIPTION: potassium potash environmentally benign selective molluscicide intermittent flow systems portable metering system	Since its introduction into North American fresh water ecosystems circa 1988, the zebra mussel has colonized the Great Lakes and the Mississippi River along with its associated tributaries. The potential blockages of industrial and municipal service water intake and discharge piping has elicited a variety of technical responses to this severe form of biofouling. ASI Group Letd. (ASI) has developed a safe and cost-effective approach to treating closed-loop and/or intermittent flow systems using potassium (K+) in the form	Figure 1: ASI Potassium Treatment of an Industrial Firewater Distribution System
		of commercially available potash, which is naturally-occurring and environmentally benign at low concentrations. ASI's potassium control process is available as a complete turnkey operating system which includes initial site assessment, related permit applications, installation	and operation of the portable metering system which accurately delivers the designated dosing. The system is relatively low-cost due to the commercial availability of potash, does not disrupt normal operations, and is effective under both warm and cold water conditions.

PROCESS/ PRODUCT APPLICATION: closed loop or semi- static water systems fire water distribution systems shipboard ballast tanks re-circulation lines nozzels sprinklers warm or cold water	Traditionally, zebra mussel control measures have included mechanical cleaning, thermal treatments, ultra-violet light, cathodic protection, and chemical oxidants such as chlorine. In closed loop or semi-static water systems, these methods can be costly and vary in terms of performance. The use of chlorine in such systems requires persistently high dosages due to rapid dissipation and must be applied at warm water temperatures (>15 oC). Preliminary fish toxicity tests have shown that potash is not toxic to non-target organisms at concentrations of 100 ppm. Lethal to adult mussels, in some instances potash has been used to prevent zebra mussel infestation in fish hatcheries. Fire water distribution systems, shipboard ballast tanks,	Figure 2: Fire Water Distribution System
		or water distribution systems with re-circulation lines are all examples of systems where ASI's potassium treatment system can eliminate biofouling due to zebra mussels. This is particularly crucial in fireline applications where only small amounts of shell material can prevent hose nozzles or sprinklers from functioning properly during an emergency response. ASI developed the first low-	temperature (<5 oC) potash treatment method for an industrial fire water distribution system in Canada. The ASI system was put on-line downstream of the pumphouse for the fire protection system at the Bayer Rubber Corp., Sarnia, Ontario, in 1996 and in the fall of 1998. ASI was also commissioned to treat the fire water distribution system at the Bruce Nuclear Plant, Kincardine, Ontario.

PROCESS/ PRODUCT OPERATION:

potassium control
agent
low ppm dosage
on-line metering
equipment
chemical storage
tank
biobox monitors
100% mortality

During early bench scale testing, ASI discovered that, in addition to pre-disposing zebra mussels to treatment by other oxidants, potassium could itself be used as a selective molluscicide at optimum concentrations and contact times. The results indicated that 30 ppm of potash administered continuously prevented primary settlement, while 40 ppm caused acute mortality in adult mussels after 2 weeks of exposure (water temperature >15 oC). Concentrations of 100 ppm yielded 100% mortality within 48 hours. More recent field applications at concentrations of 100 ppm have produced 100% mortality in eight days under extreme cold water conditions (< 5 oC). Table 1 summarizes larval settlement densities on PVC plates in flow through trials at three potassium concentrations

Figure 3: ASI Metering Panel for Potassium Control Agent

Table 1: Larval Settlement Densities

Click to View Table 1

Using dissolved oxygen data collected at various points, ASI can identify areas particularly susceptible to zebra mussel colonization. The unique dosing system, designed by ASI, can then be put on line to administer appropriate levels of potassium rich solution. The system incorporates accurate metering equipment that operates in conjunction with other on-line instrumentation (ie. flow meters) to provide feedback to the pump (see Figure 3).

The system involves no siphoning and includes a chemical storage tank with provisions for spill containment. Biobox monitors seeded with live zebra mussels can be situated strategically throughout the receiving system and used to gauge the performance of the potassium control agent. Zebra mussels are acclimatized to the receiving water system for 48 hours prior to use in biobox monitors. This non-intrusive system is removed upon completion of the designated kill.

VENDOR
INFORMATION:

ASI Group Ltd.

ASI Group Ltd. was founded in 1987 as Aquatic Sciences Inc. by a small team of technical professionals committed to provide industry and government worldwide with integrated engineering, marine and ecological services.

Over 100 professionals and technical support staff are dedicated to providing municipal and private sector clients innovative, single source, industry leading solutions in the areas of water and wastewater engineering, biofouling control,

ecological assessments, underwater inspection services and marine construction. The company’s head office facility (32,000 ft.2) is located in St. Catharines, ON. Branch offices are located in Sarnia, ON and Orchard Park, NY.

This document was originally published August, 1999.
It is best viewed with the font Times, size 12.
While OCETA has reviewed this product/process with the Vendor and
conducted limited independent investigation, OCETA assumes no responsibility
for the accuracy and completeness of the information.

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