In many resort towns, the influent loads to the
wastewater treatment system are highly variable
throughout the year. During the tourist seasons there is
an abundance of wastewater to sustain the biomass at
treatment facilities, but when the transient population
leaves, there is a drastic reduction in organic substrate.
The organic carbon supplied to the system, the
carbonaceous biological oxygen demand (CBOD), serves
as a food source for organotrophic organisms in activated
sludge systems. The ratio of food to microorganisms
(F:M) in wastewater declines correspondingly with
CBOD. Low levels of organic substrate slow cellular
growth which indicates a biomass is using emergency
carbon stores to fuel cellular function.1
Eventually, the biology in the system becomes dispersed
and unable to efficiently process influent wastewater.
Augmenting a treatment process with an external
carbon source helps to balance F:M. As a healthy F:M
is achieved, the biological treatment is supported to
provide a better-quality effluent. The remainder of
this document discusses a successful application of
Candy Carbon® (CC) for improving organic substrate
availability and biomass stability.
A small town on the eastern slope of the Sangre de Cristo
Mountains in Colorado was dealing with inconsistent
flows at their wastewater treatment plant. The SBR in
the town was receiving average flows of 0.003 MGD
when seasonal residents and visitors were present from
May to December. However, the influent dramatically
decreased when the visitors left each year between
January and April. From September to December there
were also short periods of vacancy in the town that
impacted the volume of organic inputs to the treatment
1 Gerardi, M. (2006). Wastewater Bacteria. Hoboken, New Jersey: John Wiley & Sons, Inc. Pp.73.
plant. During these times of low flow, the biology in the
SBR was not receiving an adequate supply of organic
carbon. This caused biomass mortality that produced
a rancid odor at the plant in the late winter months.
The facility needed to find a reliable organic carbon
source to keep the plant alive when influent substrate
loads were limited. The operations supervisor for the
SBR contacted BioLynceus® to inquire about their nonmethanol
carbon supplement.
Figure 1. A sequencing batch reactor similar to the one located
at the plant. A strong-smelling odor was emitting from the plant
during times of low flows in the late winter months.
BioLynceus® product, CC, was implemented in the
headworks of the system to supply the plant with high
quality organic carbon. The CC treatment kept the
biology in the reactor alive until the transient population
returned in the spring. Additionally, the effluent quality
at the SBR was improved after CC applications. The
facility remained fully functional year-round without
producing bothersome odors. Even with variable
influent loads, CC helped the SBR maintain a biomass
that efficiently processed wastewater.
BioLynceus® Candy Carbon® provides organic carbon to promote optimal F:M in SBRs.