A major problem associated with the microfouling of pipes is the blockage of flow within the piping system. This can result in the prevention of operation of the system, as well as the corrosion of metallic surfaces, poor sealing joints, erosion and abrasion of seals, increased maintenance, unbalanced forces, poor flow distribution, and increased loads on pumps. Although live mussels can cause flow reductions, the presence of zebra mussel shells (dead organisms) could also be a problem throughout the system. Some facilities that have not removed all dead organisms after implementing a reactive control method have been fouled a second time by the dead mussel shells.
If two pipes are present, one can be shut down, inspected, and cleaned if necessary, but a more preventative approach would be to increase the velocity of flow periodically. This will help to prevent settlement. Juveniles will settle in internal piping and along any submerged area with a flow rate of less than 1.5 m/sec (Claudi and Mackie 1994). The zebra mussel avoids high-velocity flow locations and is also capable of detaching from a poor settlement location and moving to a more suitable one.
Antifoulant coatings are designed to prevent zebra mussel attachment. They may be used in conjunction with periodic high velocity flow to assist in prevention of settlement. Antifoulant coatings, because of potential toxicity, should not be used if water is to be used for public consumption.
Management and Control Contents
Management and Control Options
Proactive Control Methods