Wetlands for Wastewater Treatment.

This paper provides a review of the treatment technologies, which utilize natural processes or passive components in wastewater treatment. In particular, this paper primarily focuses on wetland systems and their applications in wastewater treatment (as an advanced treatment unit or decentralized system), nutrient and pollutant removal (single and multiple pollutants, and metals), and emerging pollutant removal (pharmaceuticals). A summary of studies involving the plant (vegetation) effects, wetland design and modeling, hybrid and innovative systems, storm water treatment and pathogen removal is also included.

Optimization of operating parameters of intermittent aeration-type activated sludge process for nitrogen removal: a simulation-based approach.

Biological nitrogen removal is becoming a proven approach to reducing the total nitrogen discharged from wastewater treatment facilities. Simulation performed with intermittent aeration-type activated sludge process using Activated Sludge Model No. 1 predicted that up to 90% total nitrogen removal could be attained when the total cycle time and its anoxic phase were balanced adequately.

Combined ozone and ultraviolet inactivation of Escherichia coli.

The kinetics of Escherichia coli inactivation using ozone and ultraviolet (UV) radiation, separately and simultaneously, was evaluated at 25 degrees C in buffered (pH 6.0, 7.0 and 8.

Characterization of soluble microbial products (SMP) derived from glucose and phenol in dual substrate activated sludge bioreactors.

Soluble microbial products (SMP) generated by activated sludge cultures receiving a mixed feed of phenol and glucose were characterized with respect to molecular weight (MW) distribution, octanol-water partition coefficient (K(ow)), and Microtox toxicity. Short-term batch reactor tests using 14C-labeled substrates were performed to collect SMP derived from each substrate, while long-term tests were performed with SMP accumulated over multiple feed cycles using fed-batch reactors receiving non-labeled substrates. Yield of SMP in the batch tests, 10%-20% for phenol and 2%-5% for glucose, differed for each substrate and was independent of initial concentration.

Relative efficacy of intrinsic and extant parameters for modeling biodegradation of synthetic organic compounds in activated sludge: dynamic systems.

The utility of intrinsic and extant kinetic parameters for simulating the dynamic behavior of a biotreatment system coupled with a distributed, unstructured, balanced microbial growth model were evaluated against the observed response of test reactors to transient loads of synthetic organic compounds (SOCs). Biomass from a completely mixed activated-sludge (CMAS) system was tested in fed-batch reactors, while a sequencing batch reactor (SBR) was tested by measuring SOC concentrations during the fill and react period. Both the CMAS system and the SBR were acclimated to a feed containing biogenic substrates and several SOCs, and the transient loading tests were conducted with biogenic substrates along with one or more SOCs.

Relative efficacy of intrinsic and extant parameters for modeling biodegradation of synthetic organic compounds in activated sludge: steady-state systems.

The performance of intrinsic and extant kinetic parameters as predictors of synthetic organic compound (SOC) concentration in biotreatment systems operated at steady state was evaluated. Two laboratory-scale, completely mixed activated-sludge systems were sampled on a routine basis, and SOC concentrations were quantified using gas chromatography with flame-ionization detection coupled with solid-phase microextraction for analyte concentration. At the same time, intrinsic and extant respirometric tests were performed periodically, and the kinetic parameter estimates obtained were used to predict effluent SOC concentrations for comparison with the measured values.