Suchergebnisse

ABSTRACTThe zebra mussel, Dreissena polymorpha, is a major biofouling pest of water treatment works, irrigation systems and power stations in Europe and North America. This paper documents current problems associated with zebra mussels in English waterworks. Questionnaires and manual surveys conducted between 2001 and 2003 have revealed that over 30 water treatment works in England suffer problems associated with zebra mussels. Hundreds of tonnes of mussels are being removed each year from raw water intakes, pipelines and reservoirs. Problems have increased in. the last five years, due to a spread in the range of zebra mussels around England and the cessation of chemical treatment at the intakes of many treatment facilities during the 1990s. The importance of taking control of zebra mussels into account in planning new water supply schemes is highlighted.

AbstractWater companies in the United Kingdom have been dealing with seasonal algal blooms for many decades, with escalating costs as bloom occurrences have increased markedly with elevated demand on water supply. Environmentally friendly water treatment solutions, such as ultrasound and barley straw, are defined as those that use less energy and chemicals. Barley straw has been used quite extensively by certain UK water companies, and results are generally positive. Ultrasound has only recently been used as a treatment for algal removal, with limited results from several successful trials finding cyanobacteria to be the most susceptible algal group at field scale, with results also indicating susceptibility in other algal groups; however, energy costs are higher than barley straw. Ultrasound has been extremely successful at removing bacteria in wastewater treatment; therefore, ultrasound should be considered as an in‐works solution where its effectiveness would be enhanced while reducing energy requirements.