An electrode assembly 20 for installation and electrokinetic treatment of the substrate. The electrode assembly comprises a tube 22 for collecting and draining fluid from the substrate said tube having a sidewall comprising openings (fig. 1; 14) for allowing fluid to enter the tube from the substrate a filtration membrane 24 surrounding the tube for preventing at least some particulate matter from entering the tube; and a plurality of conducting members 26, 28 surrounding or associated with said filtration membrane, the filtration membrane (24) extending transversely away from said tube to form an extended collection region 30, comprising two adjacent spaced-apart portions of the filtration membrane for collecting fluid from the substrate for drainage by the tube . A further electrode assembly where a first longitudinal section and at least one second longitudinal section are configured such that the sections are operable for conducting electrical current independently each other is also claimed. Claims for a
