ECOCLIMATIC INFLUENCE ON WASTE STABILIZATION PONDS (WSP) EFFICIENCIES - CASE-STUDY OF THE SESIMBRA SYSTEM

Portugal has a great diversity of ecoclimatic areas and Sesimbra was chosen to carry out a study on WSP efficiencies over five years (1989 to 1993). According to Pina Manique and Albuquerque (1954), the climate is classified as Atlantic Mediterranean (AM). Some environmental and climatic parameters have been studied in order to define the area. The treatment system at Sesimbra has three ponds: anaerobic, facultative and maturation. The physical and chemical parameters studied in the WSP system were: Temperature, pH, Dissolved Oxygen, Conductivity, BOD5, GOD, nitrates, nitrites, ammonia and total nitrogen, total and volatile suspended solids, total phosphorus and orthophosphates. Algal populations and the following microbiological parameters were studied: total and fecl colifurms, fecal Streptococci, Clostridium perfringens, Pseudomonas aeruginosa and some Enterobacteriaceae. The K and K-20 kinetic parameters were studied and derived for the three ponds utilizing the seasonal regional characteristics from the surrounding area, These values were then correlated with temperature and the subsequent removal efficiencies for each pond deduced. The data obtained indicate a necessity to determine the seasonal fluctuations of the K and K-20 kinetic parameters for the WSP systems.