Response of the green mussel Pern a viridis (L.) to heat treatment in relation to power plant biofouling control

Biofouling in the cooling water circuits of coastal power stations presents considerable problems for their normal operation. Although chlorination is commonly practised, operational problems, safety concerns and environmental issues have made it necessary to look for alternative methods of control. Heat treatment is considered as a viable alternative and is being practised by a few utilities in the USA and The Netherlands. This paper presents data on the lethal and sublethal effects of temperature on the green mussel Perna viridis, a species causing fouling problems for the Madras Atomic Power Station, located on the east coast of India.

The mortality pattern and the physiological behaviour (byssus thread production, filtration rate and foot activity index) of the green mussel were studied at temperatures varying from 10°C to 46°C. Synergistic effects of salinity and temperature on mortality were also studied. Exposure of 2 mm size group mussels to a temperature of 39°C showed 50% mortality in 58 min and 100% mortality in 73 min. Mortality was strongly dependent on age (size) of the mussels, young ones being more susceptible than older ones. The study indicated that heat treatment has distinct advantages as an alternative to control mussel fouling in tropical power stations.

Key words:

• biofouling
• power station
• fouling control measures
• heat treatment
• Perna viridis

Notes

Present address: Department of Ecology, Research Working Group Aquatic Ecology, Faculty of Science, University of Nijmegen, P O Box 9010, 6500 GL Nijmegen, The Netherlands.