Bioaugmentation, or the addition of supplemental bacteria, is often used as a reactive response to an upset or to address a myriad of wastewater problems including poor BOD reduction, excessive solids carryover, and problems related to toxic material odors. The theory is that the bacteria will grow once they are added, so the actual dosage is not that critical. In concept, that is true. However, extensive work by EBS scientists and university researchers demonstrated that if the initial inoculation or seeding level is insufficient, the indigenous population crowds out the supplemented bacteria.
The minimum threshold dosage ranges between 10,000 – 1,000,000 bacteria (CFU) per mL of system volume or daily flow. Attempting to achieve this kind of inoculation level through the addition of dry bacteria is simply not cost effective. Nevertheless, bacterial products offer the customer one feature no other chemical additive does – the ability to multiply on-site prior to application.
EBS BAC Unit Feed System
The patented EBS Bacterial Acceleration Chamber (BAC unit) and our second generation BAC2 unit were designed to acclimate and grow 100 to 1000 times the bacterial population of the dry product in 24 hours. While the original BAC units are single stage units, BAC2 units are two-stage units that provide higher growth rates. The BAC units range in size from 15 – 500 gallons allowing for optimal dosage application rates. These units can accept dry product quantities ranging from 1 – 25 pounds per batch and produce up to four batches per day. This is the equivalent of up to 5000 pounds of the typical dry product.
EBS BAC Units are the most efficient bioaugmentation application system available. Because BAC Unit technology can generate such high levels of bacteria daily, the result is a greater chance for application success at an affordable cost.
EBS Bacterial Formulations for the BAC Unit
For this growth rate to be achieved, EBS developed special product formulations that provide additional nutrients and food for optimum bacterial growth. Other bacterial products do not contain the proper ingredients needed to sustain multiple log growth rates. EBS products are specifically designed for on-site cultivation in the patented EBS BAC and BAC2 units. By utilizing both the EBS products and BAC unit technology, bacterial production increases 100 -1000-fold in 24 hours.
Once through lagoons or ASBs (aerated stabilization basins) are a prime application for BAC technology due to the lack of biomass (sludge) return. Systems with low retention time can benefit from higher populations of bacteria and aggressive bioaugmentation has been shown to reduce nutrient requirements. BAC units are also helpful in conventional activated sludge systems where the indigenous bacterial population is stressed due to high loading or bioaccumulation of harmful chemicals in the biomass. For systems without full biological treatment, application of high levels of bacteria to an aerated equalization tank that discharges to a publicly owned treatment works can reduce BOD and associated surcharges.
For bioaugmentation to be effective, the dosage of bacteria must be high enough to affect the population of the system. This quantity can be accomplished with the EBS BAC and BAC2 units.