5.1. Fi6e-day biochemical oxygen demand (BOD5)
Average inflow and outflow BOD5 concentrations
for the LWDB were 263 and 93 mg:l, for an
average concentration reduction efficiency of 65%.
Median BOD5 inflow and outflow concentrations
were 81 and 31 mg:l for an efficiency of 62%. The
maximum average inlet BOD5 was 3162 mg:l at
the University of Connecticut Kellogg farm receiving
dairy wastes.
Fig. 1 summarizes the observed relationship
between BOD5 mass loading and treatment wetland
outflow concentration for all of the individual
data points in the LWDB. A simple regression
equation fitted to these data allows the estimation
of the average BOD5 wetland outlet concentration
C2 based on the inlet concentration (C1):
C20.766C1
0.878 (1)
where R20.74, C11–1679 mg:l, C21–
682 mg:l. The inclusion of hydraulic loading rate
(q) in this regression does not improve the value
of R2. Therefore, this equation cannot be used to
estimate wetland area for BOD5 reduction