Full-Scale Operation of Large Biological Nutrient Removal Facilities to Meet Limits of Technology Effluent Requirements: The Florida Experience

WEF/WERF Cooperative Study of BNR Plants Approaching the Limit of Technology: I. What Can We Learn About the Technologies?

“…An early determination was made to depart from a number of previous approaches. For instance, similar analyses of nutrient removal performance have restricted the analyses to only monthly data (Morales et al, 1991;Tetreault et al, 1989 andJimenez et al, 2007); the disadvantage of this approach is that effluent permits may possibly be set on other bases such as annual averages or daily maximum values. We therefore analyzed daily, monthly, and annual data.…”

“…Second, description of maximum month performance is often used to illustrate the treatment capabilities of treatment facilities; when only single calendar year data are examined (or even multiple calendar years) to determine maximum month treatment capability (Tetreault et al, 1989, andMorales et al, 1991), then the approach may understate or overstate performance capability of the facility, depending on how many years are picked to include in the analysis. An evaluation of Florida BNR plants using 36 months of data was able to distinguish between technologies (Jimenez et al, 2007), perhaps because the longer period consistently employed more accurately captured variability within the plants. One investigation focused on daily data rather than monthly or annual average data and was able to draw conclusions about operating conditions and process design differentiation between plants (deBarbadillo et al, 2007).…”

“…As the initial study could not resolve all relevant questions regarding nitrogen removal, results of an earlier survey of Florida plants (Jimenez, et al, 2007) …”

“…Table 4. Since the earlier Florida study (Jimenez et al, 2007) only reported monthly 95 percentile data, we report only the results of the WEF/WERF survey in Table 4 for the most important 95 and 99 percentile statistics. When using annual rolling average as a criterion, all of the plants incorporating some separate denitrification step (TMWRF, River Oaks, Fiesta Village) were able to meet the criterion of 3.0 mg/L, TN, but the two combined technology plants did not achieve LOT on an annual basis.…”

Achieving Limits of Technology (LOT) Effluent Nitrogen and Phosphorus Removal at the River Oaks Two-Stage Advanced Wastewater Treatment Plant

“…This innovative treatment process has provided flexible and reliable treatment to enable Hillsborough County to achieve the highest quality treated wastewater tributary to the Tampa Bay Estuary. Jimenez et al (2007) presented a comprehensive analysis of LOT facilities in Florida and concluded that the process configuration at the River Oaks AWTP produces the lowest nitrogen concentration in the state. Based on the information provided by plant staff, approximately 60 percent of the O&M costs are related to utilities and operation and 40 percent to chemical usage.…”