oxidation reduction potential Articles
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Municipal sludge characteristic changes under different aerating condition in a deep-shaft aeration system
A pilot-scale municipal sewage sludge deep-shaft aeration system was implemented in Lanzhou, Gansu Province of China. The reactor depth was 60 m with a diameter of 1.0 m and the sludge to be treated came from a wastewater plant in Lanzhou. In order to obtain the optimum operation conditions, analysis was conducted on the transformations of the volatile suspended solids (VSS), temperature, pH, ...
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Sludge reduction and performance analysis of a modified sludge reduction process
A modified sludge process reduction activated sludge (SPRAS) technology was developed by inserting a sludge process reduction (SPR) module, composed of an aeration tank and a settler, before the activated sludge system was proposed in this study. Compared with the anaerobic/anoxic/aerobic (AAO) process, the SPRAS resulted in a remarkable decrease in sludge production by 76.6%; sludge ...
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Influence of nitrite on the removal of Mn(II) using pilot-scale biofilters
Two pilot-scale biofilters were used to systematically investigate the influence of nitrite on biological Mn(II) removal. Gibbs free energy change (ΔG) of the redox reaction between MnO2 and NO2– was 122.28 kJ mol–1 in 298 K, suggesting that MnO2 could not react with NO2–. When nitrite in the influent was increased from 0.05 to 0.5 mg L–1, manganese oxides did not react with nitrite in ...
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High spatial resolution analysis of the distribution of sulfate reduction and sulfide oxidation in hypoxic sediment in a eutrophic estuary
Bottom hypoxia and consequential hydrogen sulfide (H2S) release from sediment in eutrophic estuaries is a major global environmental issue. We investigated dissolved oxygen, pH and H2S concentration profiles with microsensors and by sectioning sediment cores followed by colorimetric analysis. The results of these analyses were then compared with the physicochemical properties of the bottom ...
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Removal of volatile organic sulfur compounds by aeration during algae-induced black blooms in shallow lakes
High levels of volatile organic sulfur compounds (VOSCs) have frequently been detected during algae-induced black blooms, which pose an ecological threat to water bodies and their surrounding residents. In this study, aeration was applied to remove the VOSCs after the outbreak of a black bloom. The removal efficiencies under different aeration rates (A1 (0.06 m3-air min−1 m−3), A2 (0.18 ...
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Effects of chemical oxygen demand (COD)/N ratios on pollutants removal in the subsurface wastewater infiltration systems with/without intermittent aeration
The matrix oxidation reduction potential level, organic pollutants and nitrogen removal performances of eight subsurface wastewater infiltration systems (SWISs) (four with intermittent aeration, four without intermittent aeration) fed with influent chemical oxygen demand (COD)/N ratio of 3, 6, 12 and 18 were investigated. Nitrification of non-aerated SWISs was poor due to oxygen deficiency ...
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Interactions between ammonia, iron and manganese removal using pilot-scale biofilters
Pilot-scale biofilters treated with real groundwater were established to systemically investigate the interactions between ammonia, iron and manganese removal. When both of ammonia and manganese in influent were about 1 mg/L, they were quickly removed; but when manganese was above 3 mg/L, ammonia removal was affected significantly. When total iron was above 5 mg/L, the oxidization rate of ...
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Real-time process dynamics monitoring in Anammox reactors
Process dynamics in Anammox systems were evaluated through continuous monitoring of pH, oxidation reduction potential (ORP) and conductivity in two separate newly started-up sequencing batch reactors, one seeded with an enriched Anammox sludge and the other seeded with mixed activated sludge. The pH and ORP profiles exhibited characteristic patterns depending on the process dynamics during ...
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Biological nitrogen removal in a step-feed CAST with real-time control treating municipal wastewater
The performance of a 18 L step-feed cyclic activated sludge technology (CAST) combined with real-time control treating real municipal wastewater was evaluated. The operation strategies employed pH and oxidation reduction potential (ORP) as on-line control parameters, which can control the durations of oxic and anoxic phases flexibly. The obtained results showed that the studied process had ...
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Control of trichloroethylene plume migration using a biobarrier system: a field-scale study
The objective of this field-scale study was to evaluate the effectiveness of controlling trichloroethylene (TCE) plume migration using the polycolloid substrate (PS) biobarrier. The developed PS (containing soybean oil, lactate and surfactants) could release substrate to enhance the TCE dechlorination. In this study, a biobarrier comprising PS injection wells was installed. Injection wells were ...
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Influence of Fe(II) addition on heavy metal bioleaching from sewage sludge with mixed inocula
The indigenous mixed inocula were cultured and enriched from the thickened waste sewage sludge for heavy metal bioleaching. The mixed inocula were then used for bioleaching, and 2 g/L sulphur was added. The influences of FeSO4?7H2O dosage on heavy metals (Zn, Cu, Pb and Cd) and nutrients (nitrogen and phosphorus) bioleaching were investigated. Results show that the addition of FeSO4?7H2O ...
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Effects of oxidation reduction potential in the bypass micro-aerobic sludge zone on sludge reduction for a modified oxic–settling–anaerobic process
Batch experiments were conducted to determine the effect of oxidation reduction potential (ORP) on sludge reduction in a bypass micro-aerobic sludge reduction system. The system was composed of a modified oxic–settling–anaerobic process with a sludge holding tank in the sludge recycle loop. The ORPs in the micro-aerobic tanks were set at approximately +350, −90, ...
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Performance and mechanism of anaerobic biotrickling filter for removal of sulfite, sulfate, and hydrosulfite
A biotrickling filter (BTF) was designed for removal of sulfite (SO32−), sulfate (SO42−), and hydrosulfite (HSO−3) produced from flue gas adsorbent during dual-alkali flue gas desulfurization. With an SO32− concentration of 0.89 g-S/(L packing), BTF could completely remove SO32− within 3 h with an elimination capacity (EC) of 296 g-S/(m3h). With an SO42− concentration of 0.60 g-S/(L packing), ...
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Rainwater harvesting in schools in Taiwan: system characteristics and water quality
In order to understand the current status of rainwater harvesting (RWH) practices in Taiwan's schools, a study was carried out to examine the RWH system performance, water usage, and water quality in these sites. A total of 29 schools in various regions were selected for this investigation, including 7 in the northern, 7 in the central, 8 in the southern, and 7 in the eastern regions of Taiwan. ...
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Effects of C/N ratio on nitrous oxide production from nitrification in a laboratory-scale biological aerated filter reactor
Emission of nitrous oxide (N2O) during biological wastewater treatment is of growing concern. This paper reports findings of the effects of carbon/nitrogen (C/N) ratio on N2O production rates in a laboratory-scale biological aerated filter (BAF) reactor, focusing on the biofilm during nitrification. Polymerase chain reaction–denaturing gradient gel electrophoresis (PCR-DGGE) and ...
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Monitoring pH and ORP in a SHARON reactor
This paper analyses the valuable information provided by the on-line measurements of pH and oxidation reduction potential (ORP) in a continuous single high ammonia removal over nitrite (SHARON) reactor. A laboratory-scale SHARON reactor equipped with pH, ORP, electric conductivity and dissolved oxygen (DO) probes has been operated for more than one year. Nitrogen removal over nitrite has been ...
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Microorganism growth control - Case Study
KDF Process Media uses Oxidation Reduction Process for Scale and Bacteria Removal A plastic injection molding plant uses KDF media to control microorganisms and eliminate scale build-up in cooling towers-at 25% of the cost of chemical treatments. Photo courtesy of Marley Tooling Technologies, Inc. KDF process media are incorporated into carbon blocks and other matrices for bacteria removal and ...
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Destabilization dynamics of clay and acid-free polymers of ferric and magnesium salts in AMD without pH adjustment
The physicochemical treatment was employed to treat acid mine drainage (AMD) in the removal of turbid materials using clay only (exp A) and a combination of clay, FeCl3 and Mg(OH)2 (exp B) to form a polymer. A 5 g sample of clay (bentonite) was added to 1.2 L of AMD and treated in a jar test at 250 rpm for 2 min and reduced to 100 rpm for 10 min. A 200 mL sub-sample from the 1.2 L mother ...
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Performance and metabolic aspects of a novel enhanced biological phosphorus removal system with intermittent feeding and alternate aeration
A novel enhanced biological phosphorus removal (EBPR) system, which combined the intermittent feeding design with an anaerobic selector, was examined using on-line oxidation reduction potential (ORP), nitrate and ammonium probes. Two experimental periods were investigated: the aerobic and anoxic phases were set at 40 and 20 minutes respectively for period I, and set at 30 and 30 minutes for ...
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Case study – benzene contamination pilot study - retail gasoline site, Northglenn, Colorado
Introduction LTE was contracted by Shell Oil Products US (Shell) to conduct a pilot test program at a petroleum hydrocarbon impacted retail facility north of Denver, Colorado. The goals of the pilot program were to: 1) Determine the viability of using a carbon-based injectate (RPI’s BOS 200®) to remove hydrocarbons from soil and groundwater, 2) Assess transient hydraulic conditions ...
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