TABLE OF CONTENTS Pages Symposium 1 - the National Sea ...

quality, specifically the tank ammonia and nitrite level.
Table 1. Backwash regime and mixing duration for propeller-washed beadfilters using various
media at different feeding rates
Feed Loading
Rate
Backwash Frequency
(per day)
(kg/m 3 /day) Beads Modified
Beads
24
32
36
Sampling Protocols
4
Mixing Duration
(seconds)
Tubes Beads Modified
Beads
Tubes
4 3 3 15 20 20
NA 3 3 NA 25 25
NA 4 4 NA 25 30
The objective of each experiment was to determine the filter’s performance once steady state
was reached for two weeks at the target-feeding rate. Therefore, whenever the feeding or
backwashing rate was adjusted, the systems were allowed to acclimate for the required
period. During these periods of adjustment water quality was monitored daily using a Hach
2010 spectrophotometer and reagents. Once steady performance was achieved in all three
systems, water samples were taken from filter influent and effluent ports from each system
for 3 consecutive days.
Influent and effluent water sampling was conducted according to a standardized analytical
protocol. The protocol requires influent and effluent sampling for primary parameters (TAN,
NO2, BOD5, TSS, and Turbidity), and determination of critical secondary parameters (pH,
alkalinity, temperature, dissolved oxygen, and flow rate). These secondary parameters were
analyzed immediately by the research team at AST due to instability of these parameters. This
sampling regime allows the filter’s physical performance (flow rate, headloss, airflow
demands, and sludge loss rates) to be studied in light of actual loading regimes experienced
by the filter. Water flow and temperature were also recorded at the time of sampling. The
remaining portion of the sample was placed on ice and shipped immediately, via commercial
bus line, to the CEASL water quality lab in the Department of Civil and Environmental
Engineering at Louisiana State University for analysis of remaining parameters by
standardized methods (Table 2) (APHA, 1996). Each water quality parameter was analyzed
in triplicate and mean values were determined. All data was then transferred to AST were
it was transferred in spreadsheet format for complete analysis.