The surface water quality preservation is dependent on the used technology of wastewater purification, waters that are thrown in natural streams and on the used methods for the purification efficiency evaluation. The field microbiological test (FMT) is made of a concentrated culture medium that allows the evidencing of enterobacteria below values of 100/cubic cm, therefore it was used for sanitary ranking of treated wastewaters at the sewage treatment plant of Timisoara (Romania). We noted a 100% correlation between FMT and the official coliform bacteria test.

This paper presents the results obtained after an alternative treatment (aerobic and anaerobic) of the animal slurry. We discussed only about the problems related to the effects of denitrification and dephosphatation on coliform bacteria. We noticed a good decontamination of the slurry using alternatively the two procedures. To determine the decontamination degree we used the classical multiple tubes method. The same samples were examined through the field microbiological test (FMT) adding Kovacs reagent. There is a concordance between the coliform bacteria determined through the classical method and the number determined through FMT to which the Kovacs reagent adding increases the sensitivity degree.