Influence of Operating Parameters on the Biodegradation of Steroid Estrogens and Nonylphenolic Compounds during Biological Wastewater Treatment Processes

Abstract

Abstract. This study investigated operational factors influencing the removal of steroid 18 estrogens and alkylphenolic compounds in two sewage treatment works, one a 19 nitrifying/denitrifying activated sludge plant and the other a nitrifying/denitrifying 20 activated sludge plant with phosphorus removal. Removal efficiencies of >90% for 21 steroid estrogens and for longer chain nonylphenol ethoxylates (NP 4-12 EO) were observed 22 at both works, which had equal sludge ages of 13 days. However, the biological activity 23 in terms of milligrams of estrogen removed per tonne of biomass was found to be 50-60% 24 more efficient in the nitrifying/denitrifying activated sludge works compared to the works 25 which additionally incorporated phosphorus removal. A temperature reduction of 6°C 26 had no impact on the removal of free estrogens, but removal of the conjugated estrone-3-27 sulphate was reduced by 20%. The apparent biomass sorption (LogKp) values were 28 greater in the nitrifying/denitrifying works than those in the nitrifying/denitrifying works 29 with phosphorus removal for both steroid estrogens and alkylphenolic compounds 30 possibly indicating a different cell surface structure and therefore microbial population. 31The difference in biological activity (mg tonne -1 ) identified in this study, of up to seven 32 2 times, suggests that there is the potential for enhancing the removal of estrogens and 33 alkylphenols if more detailed knowledge of the factors responsible for these differences 34 can be identified and maximised, thus potentially improving the quality of receiving 35 waters. 36 37 Introduction 38

Fate and seasonal variation of endocrine-disrupting chemicals in a sewage treatment plant with A/A/O process

“…Results indicate that the average log K d values of target EDCs (except E3) followed the same order as their log K ow values, and were also similar to those reported by Koh et al [31]. On this basis, the distribution proportion of each EDC in the solid phase of return sludge (D) could be readily estimated by the following equation [33]:…”

“…Koh et al [31] found that every six-degree drop in sewage temperature could decrease the removal efficiency of E1 sulfate by ca. 20% in a nitrifying/denitrifying process, thus inferring that the low temperature in winter could bring down the activity of arylsulfatase enzymes or reduce the bacteria population containing these enzymes.…”

Occurrence and removal of antibiotics in ecological and conventional wastewater treatment processes: A field study

“…However, previous studies have shown inconsistent results. Castiglioni et al (2006) reported an enhanced removal of amoxicillin, atenolol, bezafibrate, enalapril and SMX with increasing temperature, whilst Koh et al (2009) found a decrease in temperature from 18 to 12 C did not affect the removal of steroid estrogens and nonylphenolic compounds in the AS process.…”

Removal of steroid estrogens in carbonaceous and nitrifying activated sludge processes

“…Based on observations at full-scale and laboratory scale, researchers have alluded to the importance of redox conditions (Matsui et al, 2000;Joss et al, 2004), hydraulic retention time (HRT) (Svenson et al, 2003) and solids retention time (SRT) (Johnson and Sumpter, 2001;Clara et al, 2005;Koh et al, 2008) as possible unifying parameters to explain the disparity between reported ASP estrogen removal efficiencies. A recent comparative study of two full-scale ASPs operated at nearidentical SRT (Koh et al, 2009) reported similar estrogen removal of > 90%, however, differing specific biomass activities (µg estrogen degraded per kg biomass per day, where Σ EST is the sum of dissolved and adsorbed components of five studied compounds) of 84 and 39 µg ΣEST kg -1 biomass d -1 for the nitrification/denitrification and nitrification/denitrification/phosphorus removal ASP respectively led the authors to conclude that enhancement of estrogen biodegradation could be facilitated by the appropriate microbial population. Particular emphasis has been given to the role of nitrification on the biodegradation of the more recalcitrant EE2; the hypothetical advantage of nitrification has been cited as the augmented cometabolic oxidation observed with other organic compounds in the presence of the ammonium monooxgenase (AMO) enzyme (Vader et al, 2000).…”