Nikolajsenroach5289

The MCLR reaction with free chlorine was strongly affected by temperature and the presence of DOM, while changes in ionic strength and alkalinity had little effect. Free chlorine in the presence of DOM, originating from both terrestrial and microbial sources, exhibited two-stage decay. The initial chlorine demand in the first 15 s of reaction can be determined by the dissolved organic carbon (DOC) concentration (initial chlorine demand = 1.8 × DOC), and the second-order rate constants for the later slower decay correlated well with SUVA254 (kapp,DOM = 0.73 × SUVA254 - 0.41). The results yielded a practical model to predict the decay of MCLR during chlorination of waters with varied water quality characteristics.Powdered activated carbon (PAC) is increasingly used as tertiary treatment for the removal of trace organic contaminants (TrOCs) from wastewater (WW). To enhance the sorption kinetics and capacity, the PAC particles can be milled down to superfine powdered activated carbon (SPAC). However, the small-grained SPAC particles are prone to aggregation, which may impact their treatment performance. In this study we examined the effect of SPAC dispersion and aggregation on TrOC removal kinetics and sorption capacity. Specifically, we assessed how two interventions that modulate the apparent size of SPAC - ultrasonication and coagulation - affect the uptake of TrOCs in secondary WW effluent. We quantified the removal of fourteen TrOCs, of which twelve are indicator substances for micropollutant removal in WWTPs as designated by the Swiss Water Protection Ordinance. We determined that at high SPAC doses (> 1.6 mgSPAC/mg Dissolved Organic Carbon [DOC]), the TrOC removal kinetics were fast even for aggregated SPAC, such that SPAC dispersal by ultrasonication yielded no benefit. At low SPAC doses ( less then 1.6 mgSPAC/mgDOC) and contact times ( less then 2 minutes) ultrasonication was beneficial, in particular if the SPAC particles reached complete dispersion prior to exposure to TrOCs. However, the energy consumption of such an ultrasonication step should be carefully weighed against the additional energy requirement associated with using a higher SPAC dose. Finally, a coagulant to mitigate membrane fouling can be added simultaneously with the SPAC without compromising the TrOC removal efficiency. We conclude that under realistic SPAC application scenarios in WWTPs, interventions that disperse SPAC during TrOC sorption are not necessary, and processes that aggregate SPAC are acceptable.Bacteria capable of simultaneous nitrification and denitrification (SND) and phosphate removal could eliminate the need for separate reactors to remove nutrients from wastewater and alleviate competition for carbon sources between different heterotrophs in wastewater treatment plants (WWTPs). Here we report a newly isolated Thauera sp. strain SND5, that removes nitrogen and phosphorus from wastewater via SND and denitrifying-phosphate accumulation, respectively, without accumulation of metabolic intermediates. 2-Propylvaleric Acid Strain SND5 simultaneously removes ammonium, nitrite, and nitrate at an average rate of 2.85, 1.98, and 2.42 mg-N/L/h, respectively. Batch testing, detection of functional genes, nitrogenous gas detection and thermodynamic analysis suggested that nitrogen gas, with hydroxylamine produced as an intermediate, was the most likely end products of heterotrophic ammonium oxidation by strain SND5. The generated end products and intermediates suggest a novel nitrogen removal mechanism for heterotrophic ammonium oxidation in strain SND5 (NH4+→NH2OH→N2). Strain SND5 was also found to be a denitrifying phosphate-accumulating organism, capable of accumulating phosphate, producing and storing polyhydroxybutyrate (PHB) as an intracellular source of carbon while using nitrate/nitrite or oxygen as an electron acceptor during PHB catabolism. This study identifies a novel pathway by which simultaneous nitrogen and phosphorus removal occurs in WWTPs via a single microbe.Ozonation of secondary wastewater treatment plant effluent for the abatement of organic micropollutants requires an accurate process control, which can be based on monitoring ozone-induced changes in dissolved organic matter (DOM). This study presents a novel automated analytical system for monitoring changes in the electron donating capacity (EDC) and UV absorbance of DOM during ozonation. In a first step, a quantitative photometric EDC assay was developed based on electron-transfer reactions from phenolic moieties in DOM to an added chemical oxidant, the radical cation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS·+). The assay is highly sensitive (limit of quantification ∼0.5 mgDOC·L-1) and EDC values of model DOM isolates determined by this assay were in good agreement with values determined previously by mediated electrochemical oxidation (slope = 1.01 ± 0.07, R2 = 0.98). In a second step, the photometric EDC measurement method was transferred onto an automated fluidic system coupled to a photometer (EDC analyzer). The EDC analyzer was then used to monitor changes in EDC and UV absorbance of secondary wastewater effluent treated with ozone. While both parameters exhibited a dose-dependent decrease, a more pronounced decrease in EDC as compared to UV absorbance was observed at specific ozone doses up to 0.4 mgO3·gDOC-1. The concentration of 17α-ethinylestradiol, a phenolic micropollutant with a high ozone reactivity, decreased proportionally to the EDC decrease. In contrast, abatement of less ozone-reactive micropollutants and bromate formation started only after a pronounced initial decrease in EDC. The on-line EDC analyzer presented herein will enable a comprehensive assessment of the combination of EDC and UV absorbance as control parameters for full-scale ozonation.The forward osmosis-reverse osmosis (FO-RO) hybrid process has been extensively researched as part of attempts to reduce the high energy consumption of conventional seawater reverse osmosis in recent years. FO operating conditions play a substantial role in the hybrid process, dictating not only the performance of the entire system but also the propensity for fouling, which deteriorates performance in long-term field operations. Therefore, determining the optimal FO operating conditions with regard to membrane fouling may promote sustainable operation through efficient fouling control. This study thus evaluated the influence of each hydrodynamic operating condition (feed flowrate, draw flowrate, and hydraulic pressure difference) and their synergistic effects on fouling propensity in a pilot-scale FO operation under seawater and municipal wastewater conditions. Fouling-induced variation in water flux, channel pressure drop, diluted concentration, and the resulting specific energy consumption (SEC) were comparatively analyzed and utilized to project performance variation in a full-scale FO-RO system.