ALKALINE PROCESSING BY CLOSED SYSTEM FOR MORGAN CITY AND SHREVEPORT, LOUISIANA

This paper is a compilation of experimental data obtained from studies conducted at Morgan City and Shreveport, Louisiana wastewater treatment plants by Tulane University in conjunction with Bioset, Inc. At each of the plants, a closed alkaline system is in place to treat the municipal solids. Experimental studies were conducted at the Morgan City plant to determine the optimum conditions for disinfection utilizing a closed alkaline system. The main parameters that effect disinfection include: (1) ammonia concentration, (2) exposure time, (3) temperature, (4) suspended solids content, and (5) storage time. From the data, the inactivation of helminth eggs such as Ascaris have been enhanced by 50% to 99% at temperature ranges of 35oC to 55oC as compared to the time required for pathogen inactivation related to just the time/ambient temperature phenomenon alone. In the next few years, it is expected that alkaline disinfection of biosolids will be optimized in relation to the factors stated above. Once this relationship is clearly defined and the most advantageous combination established, it would allow the development of a process that will be more energy efficient, cost effective, and be better in controlling potential odorous emissions. Also, the two locations are successfully reusing the alkaline biosolids. At the Morgan City location, the biosolids are used as fertilizer on sugar cane fields. In Shreveport, a turf grass farm is being established on site to provide additional income for the city of Shreveport along with the complete reuse of their treated biosolids.