Steroid estrogens in primary and tertiary wastewater treatment plants

The concentrations of two natural estrogens (Estrone (E1) and Estradiol (E2)) and one synthetic progestin (Ethinylestradiol (EE2)) were measured for different unit operations in an advanced sewage treatment plant and in a large coastal enhanced primary sewage treatment plant. The average influent concentration to both plants was similar – 55 and 53 ng/L for E1 and 22 and 12 ng/L for E2 for the advanced and enhanced primary STPs, respectively. The activated sludge process at the advanced STP removed up to 85% and 96% of E1 and E2, respectively. The enhanced primary sewage treatment plant was mostly ineffective at removing the steroids with only 14% of E1 and 5% of E2 being removed during the treatment process. EE2 was not been detected during the study period in the influent or effluent of either STP. The difference in the observed removal between the two plants is primarily linked to plant performance but the extent to which removal of steroid estrogens is due to bacterial metabolism (i.e. the advanced STP) rather than adsorption to the bacterial biomass remains unclear. The poor removal observed for the coastal enhanced primary STP may have implications for the receiving environment in terms of a greater potential for abnormal reproductive systems in marine animals, particularly if discharges are into large bays or harbours where flushing is limited

Fate of Steroid Estrogens in Australian Inland and Coastal Wastewater Treatment Plants

A comparison of estrone (E1), 17b-estradiol (E2) and 17a-ethinylestradiol (EE2) removal at a coastal enhanced primary and inland advanced sewage treatment plant (STP) is reported. The average concentration of estrogens in the raw sewage is similar to reports in other studies. The sequential batch reactor at the advanced STP removed on average 85% of the incoming E1 and 96% of the E2. Further removal was observed during later microfiltration with the estrogen concentration below detection (<0.1 ng.L-1) after reverse osmosis. Some 6% of the influent E1+E2 was removed in the waste activated sludge. The detection of EE2 in the waste activated sludge (0.42 ng.g-1 solids dry weight), undetectable in the raw sewage, suggests that EE2 is resistant to biological treatment in the sequential batch reactor and is primarily removed due to sorption. Little estrogen removal was observed at the enhanced primary with only 7% of E1 and 0% of E2 removed. Low removal is expected based on the degree of estrogens partitioning in the organic fraction given the relatively low solids concentration, but surprisingly, some 43% of E2, 24% of E1 and 100% of EE2 remains associated with the solids fraction in the treated effluent. Further research is necessary to determine whether the low level of estrogen removal for the coastal treatment plant will adversely affect the receiving marine environment

The Ginninderra CH4 and CO2 release experiment: An evaluation of gas detection and quantification techniques

A methane (CH4) and carbon dioxide (CO2) release experiment was held from April to June 2015 at the Ginninderra Controlled Release Facility in Canberra, Australia. The experiment provided an opportunity to compare different emission quantification techniques against a simulated CH4 and CO2 point source release, where the actual release rates were unknown to the participants. Eight quantification techniques were assessed: three tracer ratio techniques (two mobile); backwards Lagrangian stochastic modelling; forwards Lagrangian stochastic modelling; Lagrangian stochastic (LS) footprint modelling; atmospheric tomography using point and using integrated line sensors. The majority of CH4 estimates were within 20% of the actual CH4 release rate (5.8 g/min), with the tracer ratio technique providing the closest estimate to both the CH4 and CO2 release rates (100 g/min). Once the release rate was known, the majority of revised estimates were within 10% of the actual release rate. The study illustrates the power of measuring the emission rate using multiple simultaneous methods and obtaining an ensemble median or mean. An ensemble approach to estimating the CH4 emission rate proved successful with the ensemble median estimate within 16% for the actual release rate for the blind release experiment and within 2% once the release rate was known. The release also provided an opportunity to assess the effectiveness of stationary and mobile ground and aerial CH4 detection technologies. Sensor detection limits and sampling rates were found to be significant limitations for CH4 and CO2 detection. A hyperspectral imager\u27s capacity to image the CH4 release from 100 m, and a Boreal CH4 laser sensor\u27s ability to track moving targets suggest the future possibility to map gas plumes using a single laser and mobile aerial reflector

The FLUXNET2015 dataset and the ONEFlux processing pipeline for eddy covariance data

The FLUXNET2015 dataset provides ecosystem-scale data on CO2, water, and energy exchange between the biosphere and the atmosphere, and other meteorological and biological measurements, from 212 sites around the globe (over 1500 site-years, up to and including year 2014). These sites, independently managed and operated, voluntarily contributed their data to create global datasets. Data were quality controlled and processed using uniform methods, to improve consistency and intercomparability across sites. The dataset is already being used in a number of applications, including ecophysiology studies, remote sensing studies, and development of ecosystem and Earth system models. FLUXNET2015 includes derived-data products, such as gap-filled time series, ecosystem respiration and photosynthetic uptake estimates, estimation of uncertainties, and metadata about the measurements, presented for the first time in this paper. In addition, 206 of these sites are for the first time distributed under a Creative Commons (CC-BY 4.0) license. This paper details this enhanced dataset and the processing methods, now made available as open-source codes, making the dataset more accessible, transparent, and reproducible.Peer reviewe

Kinetics of Fe(III) precipitation in aqueous solutions at pH 6.0–9.5 and 25 °C

The kinetics of Fe(III) precipitation in synthetic buffered waters have been investigated over the pH range 6.0–9.5 using a combination of visible spectrophotometry, 55Fe radiometry combined with ion-pair solvent extraction of chelated iron and numerical modeling. The rate of precipitation, which is first order with respect to both dissolved and total inorganic ferric species, varies by nearly two orders of magnitude with a maximum rate constant of 16 ± 1.5 × 106 M−1 s−1 at a pH of around 8.0. Our results support the existence of the dissolved neutral species, Fe(OH)30, and suggest that it is the dominant precursor in Fe(III) polymerization and subsequent precipitation at circumneutral pH. The intrinsic rate constant of precipitation of Fe(OH)30was calculated to be allowing us to predict rates of Fe(III) precipitation in the pH range 6.0–9.5. The value of this rate constant, and the variation in the precipitation rate constant over the pH range considered, are consistent with a mechanism in which the kinetics of iron precipitation are controlled by rates of water exchange in dissolved iron hydrolysis species

The effect of dissolved natural organic matter on the rate of removal of ferrous iron in fresh waters

The ease of removal of iron in water treatment is determined principally by the form of iron present. If iron is complexed to natural organic matter (NOM) and present in dissolved form, it is quite difficult to remove by conventional deep-bed filtration methods while if present as particulate iron oxyhydroxides it is readily removed. A major source of iron in reservoirs is the benthic sediments which, on becoming anoxic, release ferrous iron (Fe(II)) to the water column. This Fe(II) may either bind to NOM and be retained in dissolved form or may form inorganic hydroxyl complexes which oxidize to Fe(III) species which typically precipitate rapidly. In this paper, we report on studies of the kinetics of Fe(II) removal from solution in the presence and absence of the IHSS standard Suwannee River Fulvic Acid (SRFA). Oxidation of inorganic Fe(II) by oxygen is negligible at low pH but addition of organics changes the kinetics of removal of Fe(II) remarkably, reducing the half life of Fe(II) from hours to minutes. Increasing the concentration of SRFA also enhances the degree of Fe(II) removal. Experimental results obtained over a wide range of conditions are successfully described using a kinetic model which accounts for the transformations between Fe(II) and Fe(III) species

The FLUXNET2015 dataset and the ONEFlux processing pipeline for eddy covariance data

Abstract The FLUXNET2015 dataset provides ecosystem-scale data on CO2, water, and energy exchange between the biosphere and the atmosphere, and other meteorological and biological measurements, from 212 sites around the globe (over 1500 site-years, up to and including year 2014). These sites, independently managed and operated, voluntarily contributed their data to create global datasets. Data were quality controlled and processed using uniform methods, to improve consistency and intercomparability across sites. The dataset is already being used in a number of applications, including ecophysiology studies, remote sensing studies, and development of ecosystem and Earth system models. FLUXNET2015 includes derived-data products, such as gap-filled time series, ecosystem respiration and photosynthetic uptake estimates, estimation of uncertainties, and metadata about the measurements, presented for the first time in this paper. In addition, 206 of these sites are for the first time distributed under a Creative Commons (CC-BY 4.0) license. This paper details this enhanced dataset and the processing methods, now made available as open-source codes, making the dataset more accessible, transparent, and reproducible