Ozone Dose Research Articles

UV/O3 assisted ceramic membrane reactor for efficient fouling control and DOM transformations in real textile wastewater

A ceramic membrane reactor (CMR) coupled with an up-flow anaerobic sludge blanket (UASB) reactor has been investigated to treat real textile wastewater, focusing on the synergetic effects of UV and O3 on fouling control and dissolved organic matter (DOM) transformation. The ozone treatment showed high potential in color removal but resulted in a linear (R2 = 0.996) increase in the membrane fouling rate with the increasing ozone dose; the continuous UV (254 nm) exposure significantly retarded membrane fouling by 16 folds but increased soluble chemical oxygen demand. In contrast, when intermittent (15 min ON: 15 min OFF) UV exposure and ozonation (UV/O3) were applied simultaneously, 94% color removal was reached and a synergistic effect on membrane fouling control was prominent, which increased the fouling time by 2.92 and 10.1 folds as compared to the standalone application of UV or ozone, respectively. Confocal laser scanning microscopy observation revealed proteins and polysaccharides as prominent foulants during O3 and UV treatment, respectively. UV–Vis spectroscopy and 3-D excitation-emission matrix fluorescence spectra confirmed the synergistic effects of UV/O3 in the degradation of UV280 and UV254 absorbance and fluorescent DOM. The HO• radicals played a primary role in degrading organic pollutants during UV/O3 treatment. These results provide new insights into the fouling mechanism and DOM transformation in ceramic membrane-based wastewater treatment systems, and recommend simultaneously intermittent application of UV/O3 in an external CMR coupled to UASB as a promising technology for the treatment of textile or other industrial wastewater.

Degradation of Organics and Change Concentration in Per-Fluorinated Compounds (PFCs) during Ozonation and UV/H2O2 Advanced Treatment of Tertiary-Treated Sewage

This study aimed to investigate the effect of H2O2 addition, ozone feed rate, and UV addition on the change in the concentration of organics such as CODMn, CODCr, TOC, and PFCs in tertiary-treated effluent from a sewage treatment plant (STP) during the O3 and UV/H2O2 process. The degradation of organic pollutants from tertiary effluent is a significant challenge because biological treatment cannot degrade these recalcitrant pollutants. Therefore, the O3/UV/H2O2 process was an effective method for treating recalcitrant organics. Several batch tests were conducted to investigate the direct UV photolysis, UV/H2O2, and ozone-based advanced oxidation process to degrade CODMn, CODCr, TOC, and PFCs. The chemical oxygen demand (COD) and total organic carbon (TOC) with UV irradiation showed 95% and 50% removal efficiency percentages under optimal conditions (initial pH = 6.7, H2O2 dosage = 50 mg/L, ozone feed rate = 5.8 mg/L/min. Moreover, UV irradiation, with the addition of H2O2, and a sufficient dose of ozone, demonstrated the efficient removal of organic compounds by the indication of radical oxidation. (·OH) is the dominant mechanism. However, AOPs are not sufficient to fully treat the PFC compound; thus, additional procedures are required to degrade PFCs. In this study, the removal of organic recalcitrant contaminants and the change in added PFC concentration in tertiary-treated sewage were investigated by applying the ozone-based advanced oxidation process.

A sensitivity analysis of a human exposure model using the Sobol method.

The Air Pollutants Exposure Model (APEX) is a stochastic population-based inhalation exposure model which (along with its earlier version called pNEM) has been used by the U.S. Environmental Protection Agency (EPA) for over 30 years for assessment of human exposure to airborne pollutants. This study describes the application of a variance decomposition-based sensitivity analysis using the Sobol method to elucidate the key APEX inputs and processes that affect variability in exposure and dose for the simulated population. Understanding APEX's sensitivities to these inputs helps not only the model user but also the EPA in prioritizing limited resources towards data-collection and analysis efforts for the most influential variables, in order to maintain the quality and defensibility of the simulation results. This analysis examines exposure to ozone of children ages 5-18 years. The results show that selection of activity diaries and microenvironmental parameters (including air-exchange rate and decay rate) are the most influential to estimated exposure and dose, their aggregate main-effect indices (MEIs) equaling 0.818 (out of a maximum of 1.0) for daily-average ozone exposure and 0.469 for daily-average inhaled ozone dose. The modeled person's home location, sampled from national Census data, has a modest influence on exposure (MEI = 0.079 for daily averages), while age, sex, and body mass, also sampled from Census and other survey data, have modest influences on inhaled dose (aggregate MEI = 0.307). The sensitivity analysis also plays a quality-assurance role by evaluating the sensitivities against our knowledge of the physical properties of the model.

Changes in Organics and Nitrogen during Ozonation of Anaerobic Digester Effluent

The objective of this study is to investigate the consequence of ozone dosage rate on the qualitative change in organic compounds and nitrogen in anaerobic digester effluent during the ozone process. Therefore, ozonation improves the biodegradability of recalcitrant organic compounds, quickly oxidizes the unsaturated bond, and forms radicals that continue to deteriorate other organic matter. In this study, ozonation was performed in a microbubble column reactor; the use of microbubble ozone improves the status of chemical oxygen demand (COD) and changes of organic nitrogen to inorganic compounds. The ozone injection rates were 1.0, 3.2, and 6.2 mg/L/min. The samples obtained during the ozone treatments were monitored for CODMn, CODCr, TOC, NO2−-N, NO3−-N, NH4+-N, T-N, and Org-N. The ozone dose increased 1.0 to 6.2 mg/L and it increased the degradation ratio 40% and the total organic carbon 20% during 20 min of reaction time. During the ozonation, the CODCr and CODMn values were increased per unit of ozone consumption. The ozone treatment showed organic nitrogen mineralization and degradation of organic compounds with the contribution of the microbubble ozone oxidation process and is a good option for removing non-biodegradable organic compounds. The original application of the microbubble ozone process, with the degradation of organic compounds from a domestic wastewater treatment plant, was investigated.

Nanoplastics removal during drinking water treatment: Laboratory- and pilot-scale experiments and modeling

Microplastics detected in potable water sources and tap water have led to concerns about the efficacy of current drinking water treatment processes to remove these contaminants. It is hypothesized that drinking water resources contain nanoplastics (NPs), but the detection of NPs is challenging. We, therefore, used palladium (Pd)-labeled NPs to investigate the behavior and removal of NPs during conventional drinking water treatment processes including ozonation, sand and activated carbon filtration. Ozone doses typically applied in drinking water treatment plants (DWTPs) hardly affect the NPs transport in the subsequent filtration systems. Amongst the different filtration media, NPs particles were most efficiently retained when aged (i.e. biofilm coated) sand was used with good agreements between laboratory and pilot scale systems. The removal of NPs through multiple filtration steps in a municipal full-scale DWTP was simulated using the MNMs software code. Removal efficiencies exceeding 3-log units were modeled for a combination of three consecutive filtration steps (rapid sand filtration, activated carbon filtration and slow sand filtration with 0.4-, 0.2- and 3.0-log-removal, respectively). According to the results from the model, the removal of NPs during slow sand filtration dominated the overall NPs removal which is also supported by the laboratory-scale and pilot-scale data. The results from this study can be used to estimate the NPs removal efficiency of typical DWTPs with similar water treatment chains.

Intensification of ozone mass transfer for wastewater treatment using a rotating bar reactor

As one of the advanced oxidation processes (AOPs), ozonation has been widely used in the treatment of textile dyeing wastewater. However, ozonation was limited by the mass transfer process due to the low solubility of ozone in water. In this work, a novel rotating bar reactor (RBR) was developed to enhance ozone-water mass transfer via optimizing its inner structures. The RBR with the internal structure of sieve plates combined with spoiler columns has the best mass transfer performance, which was 249% higher than that of the RBR without these structures. Furthermore, the optimized RBR was adopted to intensify the decolorization of the simulated wastewater of reactive black 5. The ozone dose was used to characterize the introduced ozone mass for treating a liter of wastewater in different reactors. The ozone dose in RBR was 150 mg/L (using O3), which was lower than that in semibatch glass reactor (567 mg/L, using O3/UV/H2O2) and in cylindrical glass cell (506.67 mg/L, using O3/US), reported in the literatures. The results indicated that RBR can achieve the same decolorization rate with less ozone dose, i.e. the RBR is more efficient. The RBR exhibited great potential application in enhancing liquid-film controlling system.

Highly efficient catalytic ozonation for ammonium in water upon γ-Al2O3@Fe/Mg with acidic-basic sites and oxygen vacancies

Catalytic ozonation has prospects in the advanced treatment of nitrogen removal, and solid base MgO can efficiently catalyze the ozonation of ammonium nitrogen. However, it is necessary to improve the problem of easy loss, difficult recovery, and low percentage of gaseous products. Here, MgO, amorphous Fe2O3, and γ-Al2O3 were selected as doping components and supports, respectively, to prepare γ-Al2O3@Fe/Mg composite catalysts with abundant acidic-basic sites and oxygen vacancies. The results show that γ-Al2O3@Fe/Mg5 can efficiently catalyze the ozonation of ammonium nitrogen (98.73%) with 67.82% gaseous product selectivity under the conditions of initial pH = 7, catalyst dosage of 112.88 g/L, and ozone dosage of 2.4 mg/min. The doping of Fe2O3 and MgO with a weaker lattice oxygen binding energy improves the gaseous product selectivity. The mechanism of ammonium nitrogen removal for γ-Al2O3@Fe/Mg5 is revealed, especially the intrinsic contribution of acidic-basic sites and oxygen vacancies. The pH and active sites play different roles in ozone decomposition for NH4+ removal. Surface hydroxyl protonation on basic sites and oxygen vacancies and electron transfer on acidic sites are responsible for ozone decomposition to hydroxyl radicals. Moreover, γ-Al2O3@Fe/Mg5 exhibits good stability, few leaching ions, and can be settled in water for easy recovery. This study suggests that γ-Al2O3@Fe/Mg5 is a good candidate for the catalytic ozonation of ammonium nitrogen.

Electro-peroxone application for ciprofloxacin degradation in aqueous solution using sacrificial iron anode: A new hybrid process

In a completely novel approach, the potential of hybridizing electro-peroxone (EP) with a sacrificial iron anode (EP/iron) was investigated. This hybrid process proved to be of extraordinary performance in the degradation of ciprofloxacin (CIP) for the first time. The obtained results revealed that EP/iron process had superior degradation performance in comparison with EP, E-H2O2/iron anode, ozonation, electrolysis/iron, and electrolysis and could completely degrade CIP in 40 min reaction time with a rate constant of 0.126 min−1 under optimal conditions. Effects of operational parameters were thoroughly evaluated and the best degradation results were achieved in pH = 3, ozone dosage 33.1 mg/L, and applied current 180 mA as an optimized condition. Inhibitory influence of naturally-occurring anions was assessed and 5 mM of bicarbonate and nitrite could suppress the CIP destruction up to 35% and 30% respectively, as the worst interferences. EP/iron process could yield the best mineralization performance among other methods utilized and eliminate over 70% of the total organic carbon (TOC) content in the reactor. Moreover, the contribution of oxidation and coagulation in EP/iron and E-H2O2/iron processes was thoroughly examined. In EP/iron process, oxidation had a 60.4% share of the TOC removal while coagulation had only 39.6% share. However, in E-H2O2/iron process, the contributions of oxidation and coagulation in TOC removal were 37.9% and 62.1% respectively, emphasizing the dominant role of free radicals over coagulant species in the EP/iron process. Eventually, the potential of the EP/iron system was investigated on real hospital wastewater and CIP and TOC content could be eliminated by up to 85% and 45% respectively, revealing the remarkable performance of the EP/iron process.

Removal of Antibiotic Resistance From Municipal Secondary Effluents by Ozone-Activated Carbon Filtration

At wastewater treatment plants (WWTPs), additional steps are introduced for removal of organic micropollutants (OMPs) from the treated effluents, especially pharmaceutical residues. At the same time, a new concern is emerging: antibiotic resistance (AR). This research studied the effect of ozonation, coagulation and granular activated carbon (GAC) filtration applied as tertiary treatment for the removal of OMPs and nutrients, on AR removal. Bacterial culture methods in selective media were used to screen for four different microorganisms: two faecal indicators (Escherichia coli and Enterococci) as antibiotic sensitive bacteria (ASB), and a resistant strain of each of these bacteria, namely Extended-Spectrum Beta-lactamase producing E. coli (ESBL-E.coli) and Vancomycin Resistant Enterococci (VRE) as antibiotic resistant bacteria (ARB). At laboratory scale, ozonation experiments (ozone dose 0.4–0.6 g O3/g DOC) and coagulation experiments using Polyaluminum chloride (PAX-214) and FeCl3 (coagulant dose 0.004–1 mM/L) were performed using secondary effluent from two municipal WWTPs. In addition in a pilot plant and full-scale plant ozonation (ozone dose 0.4 g O3/g DOC) and GAC filtration (empty bed contact time 15 min) were studied for AR removal. No significant differences were found between ARB and ASB removal for coagulation and ozonation which could indicate that ASB can be used as an initial proxy for ARB removal for these technologies. In the laboratory experiments, ozonation and coagulation showed a good removal of both ARB and ASB. However, the doses needed to reach 2–3 log removal were a factor 2.5–4 (ozonation) and 250 (coagulation) higher than applied for OMP removal (by ozonation) and phosphorus (P) removal (by coagulation). In the GAC filters, the risk of ARB enhancement occurred, especially in filters with a matured biology. Although these bacteria are not necessarily directly harmful, they can pass down their resistance to pathogenic bacteria via horizontal gene transfer.

Incorporating catalytic ceramic membrane into the integrated process of in situ ozonation, membrane filtration and biological degradation: Enhanced performance and underlying mechanisms

The integrated process comprising of in situ ozonation, ceramic membrane filtration and biologically active carbon filtration has a bright application prospect in wastewater reclamation to confront the global water crisis. Additionally, ceramic membranes of stronger catalytic activity are highly desirable so as to further increase the process cost-efficiency. In this study, a Mn-loaded catalytic membrane was tested by conducting pilot-scale experiments of the integrated process to measure its performance in enhancing pollutant removal and in alleviating membrane fouling. Lab-scale experiments were also conducted in order to investigate the underlying mechanisms in which the conventional Al2O3 membrane was used for comparison. Results showed that the integrated process with an incorporated catalytic membrane performed very well in that at a water flux as high as 80 L/m2/h and an ozone dosage of 5 mg/L, the treated water satisfied the guideline values for indirect potable reuse and membrane fouling was minimal. Reducing the ozone dosage to 4 mg/L can still achieve significant membrane fouling control effects, and maintain good effluent quality. Catalytic ozonation could lead to the generation of hydroxyl radicals, and the catalytic ozonation effect was much stronger when the catalytic membrane was used. Catalytic ozonation took place in both the membrane tank and membrane pores, with comparable contributions to the pollutant removal and membrane fouling control. Redundancy analysis (RDA) of membrane fouling characteristics showed that residual ozone concentration in membrane tank was an essential parameter and catalytic ozonation could be more effective in abating irreversible fouling than reversible fouling. RDA also confirmed that a lower ozone dosage would be sufficient for membrane fouling control when the catalytic membrane was used. This study evidently suggested the advantage of using catalytic ceramic membrane in the integrated process for efficient while economic treatment and reclamation of wastewater.

Inactivation kinetics of Salmonella enterica serovar Typhimurium NCTC 12023 in Chokanan mango (Mangifera indica L.) fruit juice by aqueous ozone treatment

Food processing industries worldwide focus on maintaining and enhancing food quality and security, particularly microbial food safety, to fulfil customer requirements. This study examined the efficacy of aqueous ozone on the inactivation of Salmonella enterica serovar Typhimurium NCTC 12023 in Chokanan mango juice (MJ) diluted with distilled water (DW) ratios (100MJ:0DW, 75MJ:25DW, and 50MJ:50DW). The inoculated MJ samples were treated at 10, 20, 30, and 40 mins with ozone doses 0.33, 0.67, 1.00, and 1.33 mg/mL. The results showed that the Bx values and mango pulp presence in the various MJ samples interfered with the S. enterica ser. Typhimurium disinfection activity by ozone. The S. enterica ser. Typhimurium inactivation and the survival curves’ concavity are more reliably measured in the kinetic Weibull model. Validation of the Weibull model produced coefficient determination (R 2 ) of 0.94–0.99, RSME of 0.1 to 0.4, bias and accuracy factor of 0.7 to 1.4, and shape parameter p<1. A fast inactivation rate for 5-log reduction of S. enterica ser. Typhimurium was observed in 50MJ:50DW sample (24.82 mins, 0.82 mg/mL) and in 75MJ:25DW sample (28.39 mins, 0.95 mg/mL), respectively. However, in the 100MJ:0DW sample, the 5-log reduction was achieved at 36.39 min with an ozone dose of 1.20 mg/mL. Nevertheless, this study’s ozone dose range from 0.33 mg/mL to 1.33 mg/mL with a treatment time of 10 to 40 mins has proven to lower and achieved a 5-log reduction of S. enterica ser. Typhimurium in all MJ samples

Chronic exposure to ozone induces cardiac antioxidant response and overexpression of either mitochondrial fision protein DRP1 and hipertrophyc-related proteins.

Pollution is considered a risk factor for cardiovascular disease; however, the mechanisms to explain this relationship are not well understood; ozone is one of the most abundant and studied air contaminants. Our study aimed to evaluate the effect of chronic exposition of rats to controlled low doses of ozone on oxidative stress, apoptosis, mitochondrial dynamics, and cardiac hypertrophy. Male Wistar rats were daily exposed to low ozone doses during 7, 15, 30, and 60days, 4h/day. Hearts were dissected, and homogenates were prepared. Oxidative stress was evaluated by TBARS and protein nitrosylation in addition to Superoxide dismutase 1 (SOD1) and Catalase levels; the apoptosis related-proteins caspase 3, caspase 9, Bax, Bcl-2, and the mitochondrial dynamic-associated proteins Fis1, Drp1, OPA1, and Mfn1 were quantified by western blot among the cardiac hypertrophy indicator alpha-actin (cardiac actin). There were no changes in the oxidative stress markers, however SOD1 expression increases. Caspase 3 expression decreased, whereas caspase 9 increased without changes in Bax or Bcl-2. Mitochondrial fission may be favored according to the increased expression of Drp1 but not changes in fusion-related proteins OPA1 and Mfn1. Finally, the molecular marker for cardiac hypertrophy was overexpressed after 30 and 60days of ozone exposition. The chronic exposition to ozone induces a deleterious effect on cardiac mitochondria. Antioxidant defenses also show changes in relation to exposure time, as well as an apparent pro-hypertrophic effect associated with altered mitochondrial dynamics.

A thorough observation of an ozonation catalyst under long-term practical operation: Deactivation mechanism and regeneration

Heterogeneous catalytic oxidation, as an efficient advanced treatment technology, has been gradually applied in industrial wastewater treatment. The fixed bed technique is one of the most popular catalytic ozonation methods. However, few studies have concentrated on the long-term operation effects on catalysts. In this study, we conducted long-term (~5 years) observations of the operation of the largest petrochemical wastewater treatment plant (treatment capacity 120,000 m3/d) with catalytic ozonation technology in China. A commercial catalyst, which uses Al2O3 pellets supporting copper oxide was applied in this plant. The results showed that the catalytic efficiency gradually decreased from 60.65% to 25.98% since 2018, and the ozone dosage to COD removal ratio (ozone/COD) also increased from 0.82 to 1.93 mg/mg as the running time continued. By means of the comparison and characterization of fresh catalyst and used catalyst, a “mucus layer” was formed by the adsorption of negatively charged extracellular polymeric substances on the positively charged catalyst surface and the interception of the catalyst layer. The mucus layer significantly reduced the catalytic efficiency by isolating ozone with catalytic active sites and releasing extra organic contaminants during the catalytic process resulting in 53.97% TOC increase in the batch test. Meanwhile, regeneration experiments revealed that the TOC removal efficiency was 4.76% and 43.48% in presence of washed catalysts and calcinated catalysts, respectively. Compared with the fresh catalyst, 73% of the catalytic activity was recovered for calcinated catalyst. Consequently, this study provides much practical information, showing positive effects on the promotion of catalytic ozonation application in actual wastewater treatment.

Studying Removal of PHCs from Deposits of Petroleum Storage Tanks by Ozonation Method: Determining Optimal Conditions by Central Composite Design Method

Introduction: The increasing trend of petroleum production in Iran and lack of proper and systematic management of waste products in the deposition of petroleum storage tanks have made the existing hydrocarbons as a major hazards to the environment. In this study, the ozonation process was used to remove the petroleum deposits.
 Materials and methods: In this experimental study, effects of pH, ozone dose, and petroleum hydrocarbons (PHCs) concentration were evaluated. In order to measure the PHCs, using the n-pentanes, the hydrocarbons were first extracted from the environment followed by detection using the GC-FID. The response surface methodology (RSM) was used to evaluate the effect of independent variables on response function.
 Results: In this study, the efficiency was calculated 45.47% in the optimal conditions of removing PHCs with respect to the optimal energy consumption for the process. Analysis of variance and regression showed that the fitted model had good agreement with the laboratory results.
 Conclusion: The results demonstrated that the advanced oxidation process (AOP) of ozone at high pH levels could be a useful method for the degradation and reduction of heavy hydrocarbons in petroleum waste. However, regarding the energy consumption, it is suggested to use less costly reactions as pretreatment or final treatment steps.

Mesoporous Fe3O4/graphene oxide nanohybrid for catalytic Ozonation: Preparation, characterization and process modeling by neural network

BackgroundCatalytic activity of graphene and its related compounds have been reported in the ozonation process. In addition, Fe3O4 has a good catalytic activity in the ozonation process. Fabrication of high porosity Fe3O4/graphene oxide nanohybrids can improve the production of reactive oxygen species. MethodsMesoporous Fe3O4/ graphene oxide nanohybrid was prepared by coprecipitation method. The catalytic activity of nanohybrid was investigated in ozonation degradation of acid red88 in the simulated wastewater. The progress of degradation process was determined using reactive oxygen species scavengers. The process was modeled by the artificial neural network. Significant FindingsThe mesoporous nanohybrid has a specific surface area of 252.7 m2/g, total pore volume of 0.353 cm3/g and mean pore diameter of 5.6 nm. Fe3O4/ graphene oxide showed superior catalytic activity compared to Fe3O4 and graphene oxide. Hydroxyl (OH·) and superoxide radicals (O2·−) were identified the main radical reactive species. The influence of ozone dosage, pH, dye and catalyst concentration, on the acid red88 degradation rate was investigated. The degradation process was pH dependent, and acidic condition was more favorable to mineralization of acid red88 than neutral or basic mediums. Chemical oxygen demand removal has reached 69% in the catalytic ozonation process, while it reached only 25% in single ozonation process. A very good agreement (R = 0.99) was observed between the calculated and experimental degradation efficiency. The results demonstrated that mesoporous nanohybrid is a promising catalyst for ozonation process, especially treating water polluted by azo dyes.

Fe3O4 catalytic ozonation of iohexol degradation in the presence of 1-hydroxybenzotriazole: Performance, transformation mechanism, and pathways

This study explored the degradation of an iodine X-ray contrast media, iohexol, under heterogeneous ozone-catalyzed oxidation by adding Fe3O4 and 1-hydroxybenzotriazole (HBT). Results show that increasing the dosages of Fe3O4 catalyst and ozone as well as solution pH were beneficial to the degradation of iohexol. The presence of low background humic acid (HA) concentration (≤10 mg/L) promoted iohexol degradation, but high HA concentration (≥20 mg/L) inhibited it. Adding HBT exhibited a similar effect on iohexol degradation as HA. The degradation rate constant of iohexol was calculated as 0.07108 min−1 in the Fe3O4/O3/HBT process ([HBT] = 5 μM) at pH 7.0, which was approximately 1.5 times higher than that in the Fe3O4/O3 process (0.04533 min−1), and 4 times higher than that in the O3 process (0.01742 min−1). Fe3O4/O3/HBT process was pH-dependent with high degradation efficiency of iohexol at pH 5 or 7. Singlet oxygen (1O2), hydroxyl radical (OH∙), and superoxide radical (O2-∙) have been identified in the Fe3O4/O3/HBT process, and the conversion of Fe2+ to Fe3+ was more obvious on the surface of Fe3O4 compared to that in the Fe3O4/O3 process. Transformation intermediates were identified, and the degradation pathways of iohexol were proposed. Overall, Fe3O4/O3 could enhance iohexol degradation compared with ozone-only system, and adding trace HBT in Fe3O4/O3 system can further enhance heterogeneous ozone-catalyzed process for rapid organic matter degradation.

Efficient removal of ibuprofen and ofloxacin pharmaceuticals using biofilm reactors for hospital wastewater treatment

Hospital wastewater is harmful to the environment and human health due to its complex chemical composition and high potency towards becoming a source of disease outbreaks. Due to these complexities, its treatment is neither efficient nor cost-effective. It is a challenging issue that requires immediate attention. This effort focuses on the treatment of hospital wastewater (HWW) by removing two selected drugs, namely ibuprofen (IBU) and ofloxacin (OFX) using individual biological treatment methods, such as moving bed biofilm reactors (MBBR) and physicochemical treatment, such as ozonation and peroxane process. The both methods are compared to find the best method overall based on effectiveness and removal efficiency. The optimal removal for ozone dosing range was nitrate (9.00% and 62.00%), biological oxygen demand (BOD) (92.00% and 64.00%), and chemical oxygen demand (COD) (96.00% and 92.00%) that required at least 10 min to reach considerable degradation. The MBBR process assured a better performance for ibuprofen removal, overall. The IBU and OFX removal was found to be 14.32–96.00% at a higher COD value and 11.33–94.00% at a lower COD value due to its biodegradation. This work strives to pave the way forward to build an HWW treatment technology using integrated MBBR processes for better efficiency and cost-effectiveness.

Smart Dielectric Barrier Discharge Plasma Decontamination: Spatially Targeted Decontamination With Actuated Ozone Distribution

This study introduces spatially targeted decontamination using a synergistic combination of dielectric barrier discharge (DBD) flow actuation and ozone generation. Here, we relate the spatial distribution of local microbial decontaminations in an enclosure to that of local ozone concentrations caused by DBD ozone generation and flow actuation using two reactors with contrasting flow actuation, the Fan and Comb reactors, run at equal power of 1 ± 0.03 W for 3.5 min. Deviations in ozone concentrations and reductions of Escherichia coli on contaminated coupons over two planes were used to quantify the utilization capacity of the generated ozone to simultaneously disinfect regions of a surface placed in the planes. Results show that uniform ozone consumption by a contaminated target, i.e., targeted decontamination, lowers ozone requirements, exposure times, and reactor energy consumption for its disinfection. Furthermore, a significant positive correlation was found between local decontamination and ozone concentrations with Pearson’s correlation, ρ (34) = 0.64; p < 0.001. Simulated ozone distribution using an experiment integrated simulation method, governed by DBD reactor geometry induced flow actuation and ozone reaction rates, is also presented for predicting DBD actuated spatial decontamination distribution. Our study shows an innovative approach of applying DBD plasma reactors for decontamination using flow actuation and ozone generation to achieve targeted killing with maximized ozone utilization lowering overall ozone dosage requirements, energy requirements, and exposure times.

Ozone Kinetic Studies Assessment for the PPCPs Abatement: Mixtures Relevance

The increasing consumption of pharmaceutical and personal care products (PPCPs) by humankind has been causing an accumulation of contaminants (commonly referred to as contaminants of emerging concern), in effluents and water resources. Ozonation can be used to improve the removal of these contaminants during water treatment to alleviate this burden. In this work, the degradation of methyl (MP), propylparaben (PP), paracetamol (PCT), sulfamethoxazole (SMX), and carbamazepine (CBZ) by ozonation was assessed both for individual compounds and for mixtures with increasing complexity (two to five compounds). Ozonation was performed at pH3 to gain an insight on the exclusive action of molecular ozone as oxidizing agent. The degradation of contaminants was described as a function of time and transferred ozone dose, and the corresponding pseudo-first order kinetic rate constants (k’) were determined. PPCPs were degraded individually within 1.5 to 10 min. CBZ was the most quickly degraded (k’ = 1.25 min−1) and MP the most resistant to ozone (k’ = 0.25 min−1). When in the mixture, the degradation rate of the contaminants was slower. For parabens, the increase of the number of compounds in the mixture led to an exponential decrease of the k’ values. Moreover, the presence of more PPCPs within the mixture increased energy consumption associated with the treatment, thereby reflecting higher economic costs.

Mitigation of inhibitory effect of THP-AD centrate on partial nitritation and anammox: Insights into ozone pretreatment

Anaerobic digestion centrate produced from thermal hydrolysis pretreated sludge (THP-AD centrate) has serious inhibitory effect on ammonium oxidizing bacteria (AOB) and anammox bacteria. This imposes huge challenge to employ partial nitritation/anammox (PN/A) process to treat THP-AD centrate. This study, for the first time, presented an effective strategy, ozone pretreatment, to alleviate such inhibitory effect. The activities of AOB and anammox bacteria increased with increasing ozone dosage, which were likely related to the transformation of organic compounds including humic acid-like and fulvic acid-like substances as well as high molecular weight (HMW) protein. Long-term operation of PN/A system further demonstrated the improved performance in term of nitrogen removal, organics degradation as well as sludge settleability and effluent solids. Nitrogen removal rate (NRR) of 0.64 Kg N/m3/d was achieved (1.38 g O3/ g COD), which was 42.2% higher compared to treating untreated THP-AD centrate. Effluent nitrate, the by-product of PN/A process, was reduced by 39.7% despite of its release in ozonation. This was due to the enhanced denitrification activity, humic acid-like and fulvic acid-like substances as well as HMW protein were significantly reduced. Overall, this study provides a promising method to improve PN/A performance and final effluent quality when treating organic-rich THP-AD centrate.