Brackish-, sea- and wastewater desalination

As a consequence of continuous growth in population, in standards of life a nd in industrial development, stress on water supplies is steadily increasi ng in the Mediterranean and other areas with water scarcity. Therefore, a n eed to use raw waters of lower quality has developed. In some of the countr ies of the Mediterranean and Middle East region, the governments have issue d new large-scale programs to recover and reuse treated municipal waste wat ers, rehabilitate salinated and contaminated wells and desalinate brackish and other difficult raw waters from marginal sources. This paper presents t rends for the above type of treatments and discusses alternatives and probl ems seen in implementing some of the possibilities. Benefits and problems e ncountered in "real-life" application of modern membrane technologies are p resented in the example of three case histories on industrial size and pilo t plants for reverse osmosis (RO) or nanofiltration (NF) treatment. Feed wa ters included are industrial, municipal and agricultural effluents as well as highly contaminated surface and well waters. For some of the cases, econ omic figures are also presented. Based on the experiences given in the case histories, conclusions for the selection of feed waters and for future tec hnical concepts are drawn.