WASTE-WATER AND SLUDGE - THE RAPID-DETERMINATION OF MICROBIAL CONTENTBY ATP BIOLUMINESCENCE

A study to optimize a rapid method for the determination of microbial content of wastewater and sludges by means of the ATP bioluminescent a ssay has been performed. Sampling, ATP extraction and testing of these complex specimens have been considered. A mayor problem was to obtain an homogeneous sampling. Diluition was also a very important step. Se veral diluitions were tested and the chosen one was 1:100. Different c hemical and physical method of extraction have been compared: cationic detergents, ultrasounds and microwaves have been tested, alone or in combination. Obtained data have shown that to combine the physical tre atments with detergents is the more effective way to achieve a satisfa ctory yield of extraction. In particular the use of ultrasounds on sam ples diluted in detergents solution allows a rapid, simple and effecti ve ATP extraction. The bacterial content determined by the bioluminesc ent assay was finally compared to results obtained using the plate cou nt method. ATP bioluminescence seems to allow a greater number of bact eria to be detected than with classical determinaton.