Results from an Australian Trial
The pumping wells had accumulated fat and grease on their walls. With time septic conditions had set in giving rise to strong malodours and the local residents had started to complain about the smell. In addition acids produced under septic conditions were damaging the structural integrity of the pipes and pumps and increasing maintenance costs.
To overcome the problem Bactube modules containing Amnite S300, a product containing organic solids, fat and grease degrading bacteria plus nutrients, were installed in nominated pumping wells.
Once the Bactubes were installed the bacteria started to degrade the fat and grease and in the process got rid of the offensive smells. There was an initial increase in the fat and grease content of the sewage as the accumulated deposits were washed off the walls and equipment within the wells. With continuing treatment the level of fat and grease in the pump wells soon decreased. As the contents of the wells were pumped out the treatment process continued along the sewerage line.
BOD and SS levels in the influent reaching the sewage treatment works peaked 6 - 8 weeks after installation of the Bactube as the bacteria in the product released the accumulated fat and grease in the pump wells and rising mains. Thereafter the average influent BOD and SS levels decreased considerably as a result of treatment of the sewage en route. The breakdown of the FOG by the bacteria into its easily degradable components has also greatly improved the efficiency of the treatment plant and allowed improved BOD effluent discharge levels to be achieved.
The lowering of the levels of hydrogen sulphide and other malodorous compounds means that the Council is no longer getting complaints from residents. Also with the removal of the septic conditions the pumping wells are remaining cleaner with little or no corrosion damage. Consequently the maintenance costs have decreased. As the treatment of the sewage begins before it reaches the treatment plant the loading on the treatment plant is reduced increasing the plant efficiency.