Treatment Efficiency In Terms Research Articles

Influence of ozone microbubble enhanced oxidation on mine effluent mixes and Daphnia magna toxicity

The mining industry often must mix different kinds of water on the mine site during pre-treatment or post-treatment before the final discharge of the treated water to the environment. Microbubble ozonation has proven to be efficient in the removal of contaminants of concern from mine water, such as metals, metalloids, and nitrogen compounds, which can persist in the environment and entail toxicity issues. This study evaluated the efficiency of ozone microbubbles combined with lime precipitation on contaminant removal and its impact on toxicity for Daphnia magna with five different mine effluent mixes from an active mine site located in Abitibi-Témiscamingue, QC, Canada. For the non-acidic mixes, two scenarios were tested: first, pre-treatment of metals using lime precipitation and a flocculant was conducted prior to ozonation; and second, ozonation was conducted prior to metals post-treatment using the same precipitation and flocculation technique. Results showed that the NH3–N removal efficiency ranged from 90% for the lower initial concentrations (1.1 mg/L) to more than 99% for the higher initial concentrations (58.4 mg/L). Moreover, ozonation without metals pre-treatment improved NH3–N treatment efficiency in terms of kinetics but entailed abnormal toxicity issues. Results of bioassays conducted on water with metals pre-treatment did not show any toxicity events but showed abnormal toxicity patterns on the mixes treated without metals pre-treatment (diluted effluents were toxic, while undiluted were not). At 50% dilution, the water was toxic, probably due to the potential presence of metal oxide nanoparticles. The confirmation of the source of toxicity requires further investigation.

Sub-arc collimator angle optimization based on the conformity index heatmap for VMAT planning of multiple brain metastases SRS treatments

ObjectiveThe aim of this study was to investigate the impact of collimator angle optimization in single-isocenter coplanar volume modulated arc therapy (VMAT) stereotactic radiosurgery (SRS) for multiple metastases with respect to dosimetric quality and treatment delivery efficiency. In particular, this is achieved by a novel algorithm of sub-arc collimator angle optimization (SACAO).MethodsTwenty patients with multiple brain metastases were retrospectively included in this study. A multi-leaf collimator (MLC) conformity index (MCI) that is defined as the ratio of the area of target projection in the beam’s eye view (BEV) to the related area fitted by MLC was applied. Accordingly, for each control point, 180 MCI values were calculated with a collimator angle interval of 1°. A two-dimensional heatmap of MCI as a function of control point and collimator angle for each full arc was generated. The optimal segmentation of sub-arcs was achieved by avoiding the worst MCI at each control point. Then, the optimal collimator angle for each sub-arc would be determined by maximizing the summation of MCI. Each patient was scheduled to undergo single-center coplanar VMAT SRS based on either the novel SACAO algorithm or the conventional VMAT with static collimator angle (ST-VMAT). The dosimetric parameters, field sizes, and the monitoring units (Mus) were evaluated.ResultsThe mean dose-volumetric parameters for the target volume of SACAO were comparable to ST-VMAT, while the conformity index (CI), homogeneity index (HI), and gradient index (GI) were reduced by SACAO. Improved sparing of organs at risk (OARs) was also obtained by SACAO. In particular, the SACAO method significantly (p < 0.01) reduced the field size (76.59 ± 32.55 vs. 131.95 ± 56.71 cm2) and MUs (655.35 ± 71.99 vs. 729.85 ± 73.52) by 41.11%.ConclusionsThe SACAO method could be superior in improving the CI, HI, and GI of the targets as well as normal tissue sparing for multiple brain metastases SRS. In particular, SACAO has the potential of increasing treatment efficiency in terms of field size and MU.

Integrated electron beam irradiation treatment with hydrogen peroxide aqueous solution to inactivate Salmonella on grape tomatoes

AbstractThis study investigated the efficacy of integrated electron beam (e‐beam) irradiation and hydrogen peroxide (H2O2) aqueous solution treatments to inactivate mixed strains of Salmonella inoculated in grape tomatoes. Whole grape tomatoes were inoculated with a mixed bacterial cocktail composed of five strains of Salmonella enterica corresponding to serotypes Rissen (SAL1449), Montevideo (SAL4599), Saintpaul (476398), and Typhimurium (ATCC 13311 and ATCC 700720), dried in a biological safety cabinet for 2 h at room temperature and then stored at 4°C for 24 h to facilitate bacterial attachment before treatment. Tomatoes in H2O2 (60 mg/L) aqueous solution were irradiated at 0.45, 0.60, 0.75, 1.0, and 1.25 kGy dose. The combined treatment of 1.0 kGy radiation dose and 60 mg/L H2O2 achieved 4‐log reductions in Salmonella. The D10−average value of Salmonella in the present study was 0.25 ± 0.01 kGy. Regarding the effect of the treatment on tomato quality, the combined application of e‐beam up to 1.25 kGy and H2O2 (60 mg/L) did not affect (p &gt; .05) the color and texture of grape tomatoes compared to non‐irradiated samples. Furthermore, the combined treatments of e‐beam and H2O2 aqueous solution reduced the dose uniformity ratio (DUR) by 7%, a relevant finding regarding commercial applications of electron beam accelerators. Exposure of the tomatoes to e‐beam and water wash with added H2O2 is a promising decontamination system for use in tomatoes and other produce processing. Further studies on the optimization of this integrated treatment are needed.Practical ApplicationsElectron beam irradiation of tomatoes immersed in hydrogen peroxide (H2O2) solution reduces the dose required to eliminate pathogens in the fresh produce. The integrated treatment ensures minimal changes to produce quality and increased treatment efficiency in terms of dose uniformity.

Anaerobic treatment of slaughterhouse wastewater: a review.

This article presents a review of anaerobic treatment technologies to treat slaughterhouse wastewater including its advantages and disadvantages. Physico-chemical characteristics and biochemical methane potential (BMP) of slaughterhouse wastewater are addressed. Various anaerobic treatment technologies are presented with the related operating parameters, viz., hydraulic retention time (HRT), organic loading rate (OLR), upflow velocity (Vup), and biogas yield vis-a-vis treatment efficiency in terms of chemical oxygen demand (COD). In addition, various factors that affect the anaerobic treatment of slaughterhouse wastewater such as high oil & grease (O & G) concentration in influent, inhibitors, volatile fatty acids (VFAs), and the loading rate are also addressed. The literature review indicated that the slaughterhouse wastewater can be treated effectively by employing any anaerobic treatment technologies at OLRs up to 5 kg COD/m3.d with more than 80% COD removal efficiency without experiencing operational problems. Anaerobic hybrid reactors (AHRs) were found the most effective among various reviewed technologies because of their ability to operate at higher OLRs (8 to 20 kg COD/m3.d) and lower HRTs (8 to 12 hrs).

Application of Mg-doped TiO2 coated buoyant clay hollow-spheres for photodegradation of organic pollutants in wastewater

The present work attempt to demonstrate a sustainable wastewater treatment process which is cost-effective, durable and employs light-weight functional material. Specifically, the study reveals the preparation of photocatalyst (Mg@TiO2) decorated on natural floatable spheres for photo-oxidation of organic pollutants under sunlight irradiation. About 10–15 mm diameter spheres were prepared mainly using clay and activated carbon. Mg@TiO2 photocatalytic particles were decorated on the surface of clay spheres and sintered at 550 °C temperature. The as-prepared photocatalyst decorated spheres were characterized by powder XRD, FTIR, SEM-EDX, and BET. The characterization results indicated well crystalline structures, adequate porosity and enough surface area, high stability and high photocatalytic activity which apparently enhanced photocatalysis. Treatment efficiency in terms of Chemical oxygen Demand (COD) was evaluated under different light sources using real-time industrial wastewater samples. The results showed about 80–90% removal of organic pollutants in textile and pharmaceutical industrial effluents within 24 h under sunlight. In addition, the recovery, recyclability, and reproducibility of the proposed photocatalyst were appreciable. The catalyst remained active and exhibited fair degradation efficiency up to 10–15 cycles. The spherical shape and buoyant nature influenced treatment efficiency by continuous spinning that made the illumination of decorated photocatalysts to photon and thereby inducing the intimate contact between pollutants and catalyst.

Applications of doped mixed metal oxide anode for the electro-oxidation treatment and mineralization of urine metabolite, uric acid

Removal of nitrogen-based contaminants present in urine wastewater has become a considerable matter of concern because of its potentially harmful effects on human health and can cause alterations to aquatic life. Hence to avoid its dangerous effects, electro-assisted technology was employed for the voidance of this metabolite with the doped-mixed metal oxide. The influence of various input factors such as time, pH, current density and NaCl dose on treatment efficiency in terms of percent degradation and energy consumption were evaluated using response surface methodology. Electrolysis results showed that 95.35% degradation of uric acid was achieved at optimized conditions. In addition, to reduce the treatment time further, attempts have been made by incorporating dual effect i.e. Photoelectrocatalysis. The anode used for multiple runs were proven to be effectively stable through XRD and SEM/EDS. Analysis of treated uric acid solution was validated in terms of COD (92%) and TOC (89%) reduction. The transformation products of uric acid were identified through LC–MS. Based on these intermediates and literature survey, an oxidative mechanism for uric acid has been proposed. The total operating cost for electro-oxidation treatment process is found to be 0.18 $/m3.

A facile ultrasonic-aided biosynthesis of ZnO nanoparticles using Vaccinium arctostaphylos L. leaf extract and its antidiabetic, antibacterial, and oxidative activity evaluation

The synthesis of nanoparticles often result in the generation of harmful chemical pollutants. As such, many researchers have focused on developing green processes, which include the biosynthesis. In this research, ZnO nanoparticles were prepared using the leaf extract of whortleberry (Vaccinium arctostaphylos L.) via a simple ultrasonic-assisted method. The morphology, crystal size and structure, surface, thermal, and optical properties of the bio-mediated ZnO sample (ZnOext) were analyzed and compared with that produced without incorporating the extract (ZnOchem). The ZnO samples were evaluated for their antidiabetic, antibacterial, as well as their sono- and photo-catalytic performances. Initially, the samples were intraperitoneal injected to alloxan-diabetic rats to examine their treatment efficiency in terms of effects on fasting blood glucose, insulin, cholesterol, high-density lipoprotein, and total triglyceride levels. The ZnOext showed significantly higher efficiency for improving the health status of alloxan-diabetic rats in contrast with other tested treatments, vis. ZnOchem, insulin, and only leaf extract. In addition, both the ZnO samples were assessed against gram-negative and gram-positive bacteria and through sono- and photo-catalytic processes for removing rhodamine B, respectively. The results of this study indicated that not only the ZnOext sample was pollution free, it also exhibited higher potentials for treating diabetic rats, bacterial decontamination, and also oxidative removal of organic compounds under the influences of ultrasound and UV irradiations when compared with ZnOchem sample.

Treatment Efficiency Enhancement of Dairy Effluent by Bioaugmentation Using Bacterial Species

Dairy wastewater mainly contains biodegradable pollutants and generally treated by using biological processes. Bacterial species plays vital role in reducing nutrients and organic waste concentration from dairy effluent to permissible limit. Activated sludge process is most commonly used for biological treatment but it has few treatment problems that lower down its efficiency, which can be increased by bioaugmentation of specific bacterial species and growing them by providing favorable environmental conditions within the system. Studies are carried out in search of bacterial species which can effectively remove particular pollutant from wastewater. Lot of researches emphasizes the importance of various bacterial species in treatment of wastewater emerging from different categories of industries. Efficiency of conventional activated sludge process can be increased by adding specific kind of bacterial species. The present study was carried out to test efficiency of lipase producing bacteria like bacillus subtilis and pseudomonas aeruginosa for the treatment of dairy wastewater. A lab scale model of aeration tank with the provision of diffused aeration was developed. Study was carried out to test the performance of reactor inoculated with pure culture of individual bacterial species in removal of different parameter including Turbidity, BOD and COD. Treatment efficiency in terms of COD removal for individual species of bacteria was studied for the period of 14 days. The Pseudomonas aeruginosa offered highest COD removal efficiency for dairy wastewater, which was 84.2%.

Comparison of Photocatalytic activity of Various Metallic and Non-metallic doped TiO2 Nano Particles for Treatment of Pharmaceutical Effluent

The use of semiconductor oxide particles such as TiO 2 as photo catalysts has shown great utility in the complete mineralization of organic compounds present in effluent. The dopant maximize the electron trapping for further inhibiting excitation recombination and thereby enhancing the oxidation of organic compounds. A pilot scale synthesis of TiO 2 nano particles has been carried out using the Sol-gel method with various metallic dopants like Iron, Copper, Cobalt, Vanadium, silver and non-metallic dopants like Boron, Phosphorus and Nitrogen. The obtained doped TiO 2 was characterized by X-ray Diffraction (XRD) to determine size, Morphology Index and Dislocation Density in order to analyze the structural, optical and surface properties of the synthesized materials. Photocatalytic activity of the various doped TiO 2 are assessed by the photocatalytic degradation of pharmaceutical effluent under ultraviolet light and Hydrogen Peroxide to compare treatment efficiency in terms of maximum removal of Chemical Oxidation Demand (COD) of pharmaceutical waste water having initial COD of 40000 mg/L. Comparison between TiO 2 nano particles and doped TiO 2 nano particles has also been carried out. From this we conclude that Ag doped TiO 2 nano particles is best among all dopants when amount of photocatalyst was 0.5 gm and H 2 O 2 (30 %) was 25 ml. Ag doped TiO 2 shows maximum COD removal efficiency of 84 % where as Boron doped TiO 2 shows minimum efficiency of 31 %. Keywords: TiO 2 Nano particles; Metallic and Non-metallic Dopants; X-ray Diffraction; Sol-Gel method; photocatalytic Oxidation

Intensification of Biological Treatment of Industrial Wastewater in Aerotanks Using Adsorbents

The use of industrial wastes as alternative adsorbents for wastewater treatment is proposed. The effective concentration of the adsorbent was determined experimentally. The results of a study of the intensification of biological wastewater treatment using activated carbon and a pulverized coke fraction are presented. The efficiency of treatment in terms of "chemical oxygen demand" during the intake of highly concentrated sewage sludge with the use of an alternative adsorbent averaged 85 %. In the biosorption system, the conservation of the species diversity of the biocenosis of activated sludge and its purifying ability was noted. In the biological treatment system, purification efficiency was recorded on average 16 % less and destabilization of the system as a whole. The carried out researches prove expediency of use of adsorbents, including production wastes, for intensification of biological wastewater treatment in aero tanks.

Release of targeted protein nanoparticles from functional bacterial amyloids: A death star-like approach

Sustained release of drug delivery systems (DDS) has the capacity to increase cancer treatment efficiency in terms of drug dosage reduction and subsequent decrease of deleterious side effects. In this regard, many biomaterials are being investigated but none offers morphometric and functional plasticity and versatility comparable to protein-based nanoparticles (pNPs). Here we describe a new DDS by which pNPs are fabricated as bacterial inclusion bodies (IB), that can be easily isolated, subcutaneously injected and used as reservoirs for the sustained release of targeted pNPs. Our approach combines the high performance of pNP, regarding specific cell targeting and biodistribution with the IB supramolecular organization, stability and cost effectiveness. This renders a platform able to provide a sustained source of CXCR4-targeted pNPs that selectively accumulate in tumor cells in a CXCR4+ colorectal cancer xenograft model. In addition, the proposed system could be potentially adapted to any other protein construct offering a plethora of possible new therapeutic applications in nanomedicine.

Multifunctional Metal–Organic Framework Nanoprobe for Cathepsin B-Activated Cancer Cell Imaging and Chemo-Photodynamic Therapy

Integration of a photodynamic therapy platform with a drug-delivery system in a porous structure is an urgent challenge for enhanced anticancer therapy. Here, an amino-functionalized metal-organic framework (MOF), which is useful as efficient delivery vehicle for drugs and provides the -NH2 group for postsynthetic modification, is chosen and well-designed for cell imaging and chemo-photodynamic therapy. The multifunctional MOF nanoprobe was first assembled with camptothecine drug via noncovalent encapsulation and then bound with folic acid as the targeted element and chlorine e6 (Ce6)-labeled CaB substrate peptide as the recognition moiety and signal switch. The designed MOF probe can realize cathepsin B-activated cancer cell imaging and chemo-photodynamic dual-therapy combining Ce6 as the photosensitizer and the camptothecine drug. Compared with the individual treatment, the dual-functional nanoprobe presents an enhanced treatment efficiency in terms of the time of chemotherapy, laser power, and irradiation time of the photodynamic therapy, which has been confirmed in cancer cells and in vivo assays. This work presents a significant example of the MOF nanoprobe as an intracellular switch and shows great potential in cancer cell targeted imaging and multiple therapies.

Bio-electro catalytic treatment of petroleum produced water: Influence of cathode potential upliftment

Treatment of petroleum produced water (PPW) was studied using bioelectrochemical system (BES) under uplifted cathode potential. The treatment efficiency in terms of COD and hydrocarbon removal was observed at 91.25% and 76.60% respectively, along with the reduction in TDS during BES operation under 400mV of cathode potential. There was also a reduction in concentration of sulfates, however, it was not significant at, since oxidative conditions are being maintained at anode. Improved oxidation of PPW at anode also resulted in good power output (−20.47mA) and also depicted improved fuel cell behaviour. The electrochemical analysis in terms of cyclic/linear sweep voltammetry also showed well correlation with the observed treatment efficiencies. The microbial dynamics of the BES after loading real field wastewater showed the dominance of species that are reported to be effective for petroleum crude oil degradation.

Fly ash based ceramic microfiltration membranes for oil-water emulsion treatment: Parametric optimization using response surface methodology

This article addresses the fabrication of ceramic microfiltration membranes (M1-M3) with uni-axial dry compaction method and fly ash, quartz and calcium carbonate as inorganic precursors. Raw material and membrane characterizations were conducted using particle size (PSD), thermo gravimetric (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM), mechanical stability, chemical stability, porosity, pore size and pure water permeability analyses. Dead-end flow microfiltration (MF) experiments were conducted to evaluate the membrane performances with 50–200mg/L synthetic oil-water emulsions. The MF experiments enabled to evaluate (M1-M3) membrane performance in terms of flux and rejection for variant combinations of feed concentrations and applied pressures. Among all membranes, M2 membrane demonstrated superior rejection (80.82–99.99%) and membrane flux (0.337–4.42×10−4m3/m2s). Response surface methodology (RSM) via central composite design (CCD) was employed to optimize and understand the interaction of possible influencing process variables on the treatment efficiency in terms of flux and rejection. The optimum parametric conditions are found to be at an applied pressure of 345kPa and feed concentration of 176.07mg/L at which M2 membrane exhibits a maximum oil rejection of 97% with permeate flux of 2.6×10−4m3/m2s.

Continuous‐flow microwave enhanced oxidation process for treating sewage sludge

AbstractThe microwave‐enhanced advanced oxidation (MW/H2O2‐AOP) treatment of sewage sludge in a continuous‐flow 915 MHz microwave system was studied. A higher H2O2 dosage at the same flow rate resulted in better solids disintegration in terms of higher soluble chemical oxygen demand. The highest soluble chemical oxygen demand concentration of 5174 mg/L was obtained at a dosage of 0.005 L/L (0.5 % v/v). A higher soluble chemical oxygen demand was obtained at a higher flow rate with the same H2O2 dosage. A substantial amount of soluble phosphorus (over 60 % of total phosphorus content) was produced for all treatments, regardless of H2O2 dosage. A first‐order reaction kinetics of soluble chemical oxygen demand was proposed in this study. Real‐time energy consumption corresponding to performance efficacy, which provides a realistic assessment of the process efficiency, was calculated. Energy consumption was found to vary between 0.22–0.29 kWh/L of sludge treated. The results demonstrated that a continuous‐flow 915 MHz microwave system resulted in high treatment efficiency in terms of nutrient release, solids disintegration, and low energy consumption, which is suitable for real‐time industrial applications.

Solid household waste characterization and fresh leachate treatment: Case of Kasba Tadla city, Morocco

This study aims to characterize solid household waste and to present physicochemical characteristics of fresh leachate before landfilling in Kasba Tadla city, Morocco. Obtained results show that household waste produced in 2013 were about 11,787 tons, or 0.27 tons/capita/year. These wastes were composed essentially of organic materials (74%), paper (8%), plastics (9%), metals (1%), and glass (0.5%). However, monthly produced leachate ranges from a maximum of 130.92 m 3 during summer and a minimum of 21.88 m 3 in winter. Moreover, leachate treatment using Upflow Anaerobic Sludge Blanket technique was accompanied by a decrease in electrical conductivity, certainly related to leachate-sediment chemical exchanges. Otherwise, the same acidity reduction phenomenon occurs when pH value increased from 4.49 to 6.17 after 24 hours, confirming the system response since the early stages of treatment. In addition, temporal evolution of the treatment efficiency in terms of COD highlighted a very important reduction which reached 94% after 5 days with an average temperature of 25˚C.

Investigation of colloidal biogenic sulfur flocculation: Optimization using response surface analysis

The colloidal properties of biogenic elemental sulfur (S0) cause solid–liquid separation problems, such as poor settling and membrane fouling. In this study, the separation of S0 from bulk liquids was performed using flocculation. Polyaluminum chloride (PAC), polyacrylamide (PAM) and microbial flocculant (MBF) were compared to investigate their abilities to flocculate S0 produced during the treatment of sulfate-containing wastewater. A novel approach with response surface methodology (RSM) was employed to evaluate the effects and interactions of flocculant dose, pH and stirring intensity, on the treatment efficiency in terms of the S0 flocculation and the supernatant turbidity removal. The dose optimization results indicated that the S0 flocculation efficiency decreased in the following order PAC>MBF>PAM. Optimum S0 flocculation conditions were observed at pH4.73, a stirring speed of 129r/min and a flocculant dose of 2.42mg PAC/mgS. During optimum flocculation conditions, the S0 flocculation rate reached 97.53%. Confirmation experiments demonstrated that employing PAC for S0 flocculation is feasible and RSM is an efficient approach for optimizing the process of S0 flocculation. The results provide basic parameters and conditions for recovering sulfur during the treatment of sulfate-laden wastewaters.

Briefing: H2O2 dosing strategy on microwave treatment of sewage sludge

A H2O2 dosing strategy for microwave enhanced advanced oxidation process treatment of sewage sludge was formulated. The timing of hydrogen peroxide introduction in a continuous-flow 915-MHz system affected the treatment efficiency in terms of solids destruction, nutrient release and volatile fatty acid (VFA) production. Introducing hydrogen peroxide into the treatment set at 60°C was found to be more effective than adding it at the beginning. The treatment set with hydrogen peroxide introduced at 60°C resulted in higher soluble chemical oxygen demand concentrations and VFAs, higher soluble total Kjeldahl nitrogen and soluble total phosphate and also improved dewaterability and settling. However, there were no differences in terms of ammonia and orthophosphate release between the two treatment schemes. It is an advantage to introduce hydrogen peroxide into the treatment set at 60°C in a continuous-flow microwave system.

Power generation and oil sands process-affected water treatment in microbial fuel cells

Oil sands process-affected water (OSPW), a product of bitumen isolation in the oil sands industry, is a source of pollution if not properly treated. In present study, OSPW treatment and voltage generation were examined in a single chamber air–cathode microbial fuel cell (MFC) under the effect of inoculated carbon source and temperature. OSPW treatment with an anaerobic sludge-inoculated MFC (AS-MFC) generated 0.55±0.025V, whereas an MFC inoculated with mature-fine tailings (MFT-MFC) generated 0.41±0.01V. An additional carbon source (acetate) significantly improved generated voltage. The voltage detected increased to 20–23% in MFCs when the condition was switched from ambient to mesophilic. The mesophilic condition increased OSPW treatment efficiency in terms of lowering the chemical oxygen demand and acid-extractable organics. Pyrosequencing analysis of microbial consortia revealed that Proteobacteria were the most abundant in MFCs and microbial communities in the AS-MFC were more diverse than those in the MFT-MFC.

Anaerobic treatment of brewary wastewater with simultaneous hydrogen production

Processes of brewery wastewater treatment with sequential use of the fermentative and bioelectrochemical methods have been investigated. A two-stage fermentation increases the rate of substrate utilization and hydrogen production. The water treatment efficiency in terms of COD in the first and second fermenters amounts to 55–65% and 65–72%, respectively. The hydrogen concentration in biogas can reach 65%. The organic acids produced in anaerobic fermentation process represent a substrate for exoelectrogenic microorganisms of bioelectrochemical fuel cell, where the secondary wastewater treatment takes place for achieving COD values of 200–400 mg/dm3. The combination of the fermentative and bioelectrochemical processes of hydrogen production makes it possible to increase its yield by a factor of 2–4 and reach the level of 7–9 moles of H2 per 1 mole of glucose.