Efficacy of Pilot-Scale Wastewater Treatment upon a Commercial Recirculating Aquaculture Facility Effluent - Aquaculture and the Environment: A Shared Destiny - page 142

reported by Sandu et al. (2008). Here, we: (1) evaluate the effectiveness of a pilot wastewater
treatment train with regard to alkalinity, pH, hardness, and nitrogenous compounds (TAN,
NO 2 - -N, NO 3 - -N and TKN), (2) the effect of nitrate feed rate on denitrification, and (3)
examine the economic feasibility of treating and reusing this aquaculture wastewater. All
abbreviations used in this chapter are presented in Table 1.
.
BRA Blue Ridge Aquaculture
BOD biochemical oxygen demand (mg/l)
cBOD 5 carbonaceous biochemical oxygen demand (mg/l)
CF chemical flocculation
COD chemical oxygen demand (mg/l)
DR denitrification reactor
NO 2 - -N nitrite-nitrogen (mg/l)
NO 3 - -N nitrate-nitrogen (mg/l)
NO x — N oxidized nitrogen species (mg/l)
OR ozone reactor
RI raw (untreated) influent
SB sedimentation basin
TAN total ammonia nitrogen (mg/l)
TF trickling filter
TKN total Kjeldall nitrogen (mg/l)
TSS total suspended solids (mg/l)
VSS volatile suspended solids (mg/l)
Y b biological (anoxic) yield (g microbial biomass produced/g substrate used)
Y NO3 - -N biological yield for NO 3 - -N (g biomass VSS/g NO 3 - -N)
Y VSS biological yield for VSS (g biomass VSS/g dissolved COD)
Y COD biological yield for COD (g biomass COD/g dissolved COD) .
Table 1. Nomenclature used in this chapter.
2. Methods
2.1 Treatment train and experimental treatments
The wastewater treatment train (Figure 1) included storage tanks, a primary sedimentation
basin, mechanical filtration using a microscreen drum filter, denitrification using a fluidized
bed biological reactor with methanol added to provide carbon and energy for cellular
growth, ozonation and foam fractionation in a bubble-contact ozone reactor, dissolved
ozone quenching in an air-bubble stripping chamber, aerobic biological treatment using a
trickling filter, and jar test-scale chemical flocculation, followed by sand filtration. A
detailed description of the pilot plant, its operation and analytical techniques may be found
in Sandu (2004) or Sandu et al. (2008).
Our evaluation of pilot plant effectiveness consisted of four different experimental
treatments (Table 2), differing by use of 6 or 4 lpm flow and recycling rates, ozone doses
between 36.6 - 82.5 mg O 3 /l water, and 6- or 9-minute ozonation times.