Sewage treatment in Malta.

Abstract

In the Maltese Islands crude sewage is discharged into the sea, the organic matter will at once begin to decompose using up the contained oxygen and destroying fish life. This fact upraised considerable public concerns over sewage disposal, particularly to the type adopted in Malta that of discharging crude sewage into the sea without any treatment. A draft European Council directive on municipal waste water treatment provided a guide to the likely European requirements on treatment of sewage. In general the requirements call for full primary and secondary treatment as well as adequate arrangements for the disposal of sludge. In Malta a waste treatment facility is available and sited at Sant Antnin limits of Marsascala, the plant was commissioned in 1983 and its main aim is to produce water for irrigation purposes. The treatment of sewage cannot be completely effected by a single process but due to various forms of impurity present it should consist of a series of processes arranged in a logical order which together produce an effluent of satisfactory purity. At Sant Antnin Waste Treatment Plant the process is divided into four stages. The preliminary stage consists of screening and oil/ grit removal. The primary treatment only consists of settling, while in the secondary treatment biological oxidation and settling takes place. In the tertiary treatment the effluent passes through sand filtration and disinfection. Samples of material at all stages of treatment are taken regularly and analysed. The aims of these analysis are quality control. Guide line values are also established for safe reuse of the waste water in agriculture. The Structure Plan for Malta issued in 1991 stated that new sewage treatment plants will be required. Three new treatment plants all related to existing outfalls will probably be required, the locations being Hinterland at Anchor Bay, Wied Ghammieq near Ricasoli and another between Sannat Valley and Victoria in Gozo. A proposed extension to the existing plant at Sant Antnin was also given importance in the structure plan. (Structure Plan 19917 Sewerage policy no. 11 ) In the 1996 budget the House of Representatives approved the expenditure fund for the upgrading of the Sant Antnin sewage treatment plant. ( The Times 7 12 December 1995)