Oxygen transfer parameters and oxygen uptake rates revisited.

This paper provides a review of the essential equations and parameters that are used to design bioreactor aeration systems. Major objectives were to determine if the log-deficit method (LDM) and non-linear regression method (NLRM) yielded different results for the volumetric oxygen mass transfer coefficient ( and dissolved oxygen (DO) saturation concentration ( . Another objective was to compare and evaluate oxygen uptake rates (OURs) from the traditional BOD bottle technique with OURs determined from mass balances around completely-mixed activated sludge (CMAS) reactors.

Comparison of oxygen transfer parameters and oxygen demands in bioreactors operated at low and high dissolved oxygen levels.

The proper design of aeration systems for bioreactors is critical since it can represent up to 50% of the operational and capital cost at water reclamation facilities. Transferring the actual amount of oxygen needed to meet the oxygen demand of the wastewater requires α- and β-factors, which are used for calculating the actual oxygen transfer rate (AOTR) under process conditions based on the standard oxygen transfer rate (SOTR). The SOTR is measured in tap water at 20°C, 1 atmospheric pressure, and 0 mg L of dissolved oxygen (DO).

Comparing two empirical models used to predict process parameter dynamics during ozonation of synthetic dye wastewater.

Ozonation of a synthetic wastewater contaminated with acid yellow 17 dye and glucose was evaluated in a semi-batch bubble column. Data collected during this study suggests that the ozonation process removed color (represented as A400) more efficiently than chemical oxygen demand (COD) regardless of initial experimental conditions. With a 40-minute run time, the maximum A400 and COD removal efficiencies were 99.

Bench-scale ozonation study of waste activated sludge.

A bench-scale ozonation study was conducted on waste activated sludge (WAS) in a 10-L, clear PVC, semi-batch, bubble column reactor. Two separate runs were performed on 5-L samples of WAS obtained from the Rocky Creek Wastewater Treatment Plant (WWTP) in Macon, Georgia. The Rocky Creek facility uses the extended aeration activated sludge process to treat domestic wastewater.

Oxidation and ozonation of waste activated sludge.

In this bench-scale study, the treatment of waste activated sludge (WAS) was evaluated using aerobic digestion and ozonation. Two, 2-L batch digesters, one aerated and the other one ozonated, were operated for 30 days in each phase of the study. The aerated digester simulated the aerobic digestion process and served as control to the ozonated digester.

Performance assessment of major wastewater treatment plants (WWTPs) in the state of Georgia.

A survey was conducted to report on the types and efficiencies of various treatment technologies being used at major wastewater treatment plants (WWTPs) in the state of Georgia. Twenty-four, full-scale wastewater treatment facilities with a design capacity of 37,850 m(3) d(-1) (10 Mg d(-1)) or greater were evaluated. One year of operating data for the 2003 calendar year was obtained from discharge monitoring reports (DMRs) provided by the Georgia Environmental Protection Division (EPD) in Atlanta.

Ozonation of acid yellow 17 dye in a semi-batch bubble column.

A semi-batch bubble column was used to evaluate the effect of ozonation on the removal of acid yellow 17 dye from water. Results indicate that ozonation is very effective at removing acid yellow 17 dye from synthetic textile wastewater. The ozone consumed to apparent dye removal ratio ranged from 2 to 15,000 mg ozone per mg of dye decolorized and was dependent on both ozonation time and apparent dye concentration.

Assessment of AWT systems in the metro Atlanta area.

A study was conducted to evaluate the performance of six advanced wastewater treatment facilities using biological nutrient removal processes as the primary mechanism for removing carbon, nitrogen, and phosphorus from domestic wastewater. One year of operating data was obtained from monthly operating reports provided by the Georgia Environmental Protection Division (EPD) in Atlanta. Additional information about facility operations and the types of chemicals used was gathered through review of EPD files and interviews with plant personnel.

Treatability study of a seafood-processing wastewater.

The unique characteristics of seafood-processing wastewater require a treatability study be performed. Wastewater from seafood-processing contains high concentrations of nitrogen and suspended solids along with large volumes of wastewater. This treatability study was undertaken using a 10 L per day, bench-scale, modified Ludzack-Ettinger (MLE) process that was designed, constructed, and operated for approximately eight (8) months.