FATE OF FECAL-COLIFORM BACTERIA IN A WASTE-WATER RETENTION RESERVOIR CONTAINING LEMNA-GIBBA L

The comparative survival of total and faecal coliform bacteria was stu died in a stable waste-water retention reservoir. The surface of the w ater reservoir was covered with a macrophyte, Lemna gibba L. Sets of d ialysis sacs were suspended in an exposed site to the sun light, while other sets of sacs were suspended beneath the thick green him of L. g ibba; where sunlight is almost absent. Total coliform bacteria regrow in sun and in sacs unexposed to sun, while faecal coliform cells expos ed to sunlight disappeared with a decay rate 0.1768 h(-1). Interesting ly, faecal coliform in sacs suspended under the L. gibba green film di d not decline during the period of the experiment.