Removal Efficiency Of Organic Compounds Research Articles

Nitrogen removal and carbon reduction of mature landfill leachate under extremely low dissolved oxygen conditions by simultaneous partial nitrification anammox and denitrification

In this study, a SNAD-SBBR process was implemented to achieve ammonia removal and carbon reduction of mature landfill leachate under extremely low dissolved oxygen conditions (0.051 mg/L) for a continuous operation of 266 days. The process demonstrated excellent removal performance, with ammonia nitrogen removal efficiency reaching 100 %, total nitrogen removal efficiency reaching 87.56 %, and an average removal rate of 0.180 kg/(m3·d). The recalcitrant organic compound removal efficiency reached 34.96 %. Nitrogen mass balance analysis revealed that the Anammox process contributed to approximately 98.1 % of the nitrogen removal. Candidatus Kuenenia achieved a relative abundance of 1.49 % in the inner layer of the carrier. In the SNAD-SBBR system, the extremely low DO environment created by the highly efficient partial nitrification stage enabled the coexistence of AnAOB, denitrifying bacteria, and Nitrosomonas, synergistically achieving ammonia removal and carbon reduction. Overall, the SNAD-SBBR process exhibits low-cost and high-efficiency characteristics, holding tremendous potential for landfill leachate treatment.

Experimental design for combined abatement of organic compounds present in urine

AbstractOrganic compounds contained in urine, such as urea and creatinine, can compete with pharmaceuticals for the electro‐generated oxidants during electrochemical treatment. In addition, urine has a large amount of chloride ions, creating opportunities to produce chlorine and aqueous‐free chlorine species via electrolysis. The aim of the present study is to analyze artificial urine as a supporting electrolyte, while studying the removal of the organic components present (urea and creatinine) by employing an experimental design approach. A 2³ factorial design was employed to evaluate the efficiency of the photo‐assisted sonoelectrochemical (EC/UV/US) process. Operating conditions were optimized using response surface methodology (MRS), namely: 11.44 mL min−1 flow, 1.940 A at 160 min. The pH was analyzed and a predominance of HOCl (pH < 7.0) can be observed. Response surface methodology was used to investigate the effects and interactions of flow rate, time, and current to track the removal efficiency of organic compounds contained in artificial urine (TOC, creatinine, and urea). Over prolonged electrolysis, the EC/US/UV process achieved removal of TOC (25.7%), creatinine (68.2%), and urea (33.3%), due to the large contribution of highly reactive radical species (•OH, •Cl, ClO−).

Prolonging the Life Span of Membrane in Submerged MBR by the Application of Different Anti-Biofouling Techniques.

The membrane bioreactor (MBR) is an efficient technology for the treatment of municipal and industrial wastewater for the last two decades. It is a single stage process with smaller footprints and a higher removal efficiency of organic compounds compared with the conventional activated sludge process. However, the major drawback of the MBR is membrane biofouling which decreases the life span of the membrane and automatically increases the operational cost. This review is exploring different anti-biofouling techniques of the state-of-the-art, i.e., quorum quenching (QQ) and model-based approaches. The former is a relatively recent strategy used to mitigate biofouling. It disrupts the cell-to-cell communication of bacteria responsible for biofouling in the sludge. For example, the two strains of bacteria Rhodococcus sp. BH4 and Pseudomonas putida are very effective in the disruption of quorum sensing (QS). Thus, they are recognized as useful QQ bacteria. Furthermore, the model-based anti-fouling strategies are also very promising in preventing biofouling at very early stages of initialization. Nevertheless, biofouling is an extremely complex phenomenon and the influence of various parameters whether physical or biological on its development is not completely understood. Advancing digital technologies, combined with novel Big Data analytics and optimization techniques offer great opportunities for creating intelligent systems that can effectively address the challenges of MBR biofouling.

The Effectiveness of Moringa Oleifera in Purifying Pegasius SP Pond Wastewater

Pond water of silver catfish (Pangasius sp) has high color value, turbidity, and organic compound with the color concentration 250 Pt-Co, turbidity 13.5 NTU, and organic concentration 197.56 mg/L. High concentration of color, turbidity, and organic compound in pond water of silver catfish caused the water should be treated. One of the treatment method is chemical treatment with coagulation-flocculation method. Pond water of silver catfish was treated into clean water using powder of Moringa seed (Moringa oleifera) as organic coagulant using coagulation-flocculation method with Jar-Test system. The aim of this research is to purify water with knowing the removal efficiency of color, turbidity, and organic compound by treating pond water of silver catfish using coagulation-flocculation method and determining optimum dose of coagulant. Jar-Test result showed the color removal efficiency as 86.00% in day 1; 90.75% in day 2; and 88.77% in day 3 with 60 ppm as optimum dose. Turbidity removal efficiency was 84,52% in day 1 and 87.80% in day 2 with 60 ppm as optimum dose. Organic compound removal efficiency was 73.87% in day 1; 77.13% in day 2, and 77.29% in day 3 with 60 ppm as optimum dose.

Graphdiyne as a novel nonactive anode for wastewater treatment: A theoretical study

Electrochemical oxidation of water to produce highly reactive hydroxyl radicals (OH) is the dominant factor that accounts for the organic compounds removal efficiency in water treatment. As an emerging carbon-based material, the investigation of electrocatalytic of water to produce OH on Graphdiyne (GDY) anode is firstly evaluated by using first-principles calculations. The theoretical calculation results demonstrated that the GDY anode owns a large oxygen evolution reaction (OER) overpotential (ηOER = 1.95 V) and a weak sorptive ability towards oxygen evolution intermediates (HO*, not OH). The high Gibbs energy change of HO* (3.18 eV) on GDY anode makes the selective production of OH (ΔG = 2.4 eV) thermodynamically favorable. The investigation comprises the understanding of the relationship between OER to electrochemical advanced oxidation process (EAOP), and give a proof-of-concept of finding the novel and robust environmental EAOP anode at quantum chemistry level.

The Enhancement of Energy Efficiency in a Wastewater Treatment Plant through Sustainable Biogas Use: Case Study from Poland

The improvement of energy efficiency ensuring high nutrients removal is a great concern for many wastewater treatment plants (WWTPs). The energy balance of a WWTP can be improved through the application of highly efficient digestion or its intensification, e.g., through the introduction of the co-substrates with relatively high energy potential to the sewage sludge (SS). In the present study, the overview of the energetic aspect of the Polish WWTPs was presented. The evaluation of energy consumption at individual stages of wastewater treatment along with the possibilities of its increasing was performed. Additionally, the influence of co-digestion process implementation on the energy efficiency of a selected WWTP in Poland was investigated. The evaluation was carried out for a WWTP located in Iława. Both energetic and treatment efficiency were analyzed. The energy balance evaluation of this WWTP was also performed. The obtained results indicated that the WWTP in Iława produced on average 2.54 GWh per year (7.63 GWh of electricity in total) as a result of the co-digestion of sewage sludge with poultry processing waste. A single cubic meter of co-substrates fed to the digesters yielded an average of 25.6 ± 4.3 Nm3 of biogas (between 18.3 and 32.2 Nm3/m3). This enabled covering the energy demand of the plant to a very high degree, ranging from 93.0% to 99.8% (98.2% on average). Importantly, in the presence of the co-substrate, the removal efficiency of organic compounds was enhanced from 64% (mono-digestion) to 69–70%.

Electrodes criticality: the impact of CRMs in the leachate electrochemical oxidation

Landfill leachate possesses high concentrations of ammonia, micropollutants, and heavy metals, and are characterised for low biodegradability. For this reason, conventional treatment technologies may result ineffective for complete pollutant removal. Electrochemical oxidation allows most of the of recalcitrant pollutants to be oxidised effectively within an easy operational and acceptable retention time, without the need to provide additional chemicals, and without producing waste materials. The mineralisation efficiency and electrode durability depend on the nature of the electrode material. The conventionally adopted anodes can contain critical raw materials (CRMs), and are subject to extreme corrosion conditions. CRM-free electrodes, such as carbon and graphite-based, exhibit a lower efficiency, and are subject to faster deactivation, or, as for lead-dioxide-based electrodes, can constitute a hazard due to the release into the effluent of the coating corrosion products. In this study, the relationship between electrode type, CRM content, and the removal efficiencies of organic compounds and ammonium-nitrogen (N-NH4) was investigated. Material criticality was estimated by the supply risk with economic importance indexes reported in the 2017 EU CRM List. The COD and N-NH4removal efficiencies were obtained from a literature analysis of 25 publications. The results show that, while single and multi-oxide-coated electrodes may contain low amounts of CRM, but with limited efficiency, boron-doped diamonds (BDD) may constitute the best compromise in terms of a reduced content of CRM and a high mineralisation efficiency.

Degradation of refractory organic compounds from dinitrodiazophenol containingindustrial wastewater through UV/H2O2 and UV/PS processes.

In this study, refractory organic compounds from dinitrodiazophenol (DDNP) containing industrial wastewater were degraded through two ultraviolet (UV)-based advanced oxidation processes: UV/hydrogen peroxide (UV/H2O2) and UV/potassium persulfate (UV/PS) processes. In both processes, the synergistic effects, operational parameters (i.e., oxidant dosage and initial pH value), and pseudo first-order constant k were systematically studied. Moreover, the reactive oxygen species formed in the UV/H2O2 and UV/PS processes were identified, and the degradation of refractory organic compounds was characterized through UV-visible spectra analysis. The improvement in biodegradability of DDNP industrial wastewater after treatment by different processes was compared. Both the UV/H2O2 (synergistic coefficient F = 61.34) and UV/PS (synergistic coefficient F = 54.85) processes showed significant, highly synergistic effects. The increase in oxidant dosage was beneficial in organic compound removal in both the UV/H2O2 and UV/PS processes, but excessive H2O2 showed a stronger inhibition of the increase in organic compound removal than that in the UV/PS process. In addition, an acidic environment was more conducive to organic compound degradation in the UV/H2O2 process, whereas the initial pH value had less of an influence on the UV/PS process. Under optimal conditions for the UV/H2O2 and UV/PS processes, the CN and COD removal efficiencies were 99.71%, 66.35%, 99.69%, and 70.81%, respectively, and the k values for COD removal were 0.0804 and 0.0824min-1. Tests to identify reactive oxygen species showed that the hydroxyl radical was the predominant oxidizing species in the UV/H2O2 process, whereas the hydroxyl and sulfate radicals were both identified in the UV/PS process, and the sulfate radical contributed the most to the degradation of organic compounds. In addition, spectrum analysis revealed that the complex structure (e.g., benzene ring, nitro group, and diazo group) of refractory organic compounds from DDNP industrial wastewater was effectively destroyed by the UV/H2O2 and UV/PS processes, and both processes improved the biodegradability (biochemical oxygen demand for 5days/chemical oxygen demand (BOD5/COD)) of DDNP industrial wastewater from 0.052 to 0.665 and 0.717, respectively. Overall, both the UV/H2O2 and UV/PS processes effectively degraded the refractory organic compounds from DDNP industrial wastewater, and the UV/PS process exhibited a higher organic compound removal efficiency and better applicability.

Removal of Volatile Solids from Greywater Using Sand Filters

Sand filtration is a primary stage of treatment for reuse of greywater. This study aimed at assessing the volatile solid removal efficiency of a sand filter and imitating its performance using analytical simulation. This study used artificial greywater, medium sand as a filtering material, and nine PVC cylinders as filter columns. Samples of the sand were collected after 6, 14 and 21 days, with the aim of specific deposit determination. The vertical distribution of specific deposit (volatile solids) in the sand filters was typical for gravitationally operated sand filters. Relatively high removal efficiency of volatile solids (51–60%) was achieved at relatively low cumulative hydraulic load. The average removal efficiency of organic compounds (detected as chemical oxygen demand) was 26.8%. Maximum specific deposit was achieved for a cumulative hydraulic load of 363.6 m. The filter coefficient was identified empirically for application of the Iwasaki formula. The filter coefficient λ was corrected for a better fit of the modelled values with measured values.

The effect of ionization energy and hydrogen weight fraction on the non-thermal plasma volatile organic compounds removal efficiency

The degree of difficulty of volatile organic compounds (VOCs) degradation in non-thermal plasma (NTP) related to their chemical structures, ionization potentials and hydrogen weight fraction was investigated. Benzene, methylbenzene, xylene, n-pentane, n-hexane, cyclohexane, ethyl acetate, ethyl propionate, ethyl butyrate, propanone, 2-butanone and 2-pentanone, total 12 VOCs were chosen as the typical VOC agents from the four main types of VOCs such as aromatic hydrocarbons, alkanes, ketones and esters with different structures and ionization potentials. The experimental results indicate that the ionization potential is a parameter indicating the destruction efficiency of VOCs by NTP. It is a trend that the higher the ionization potentials are, the weaker the reactivity of VOCs and radicals, and the more difficult it is to destroy VOCs at the same initial VOC concentration and the specific input energy. The influence of hydrogen weight fraction on the decomposition efficiency is different from the ionization potential one’s. For aromatic hydrocarbons, ketones and esters, the higher removal efficiency is observed with the higher percentage of hydrogen; for alkanes, the situation is just the opposite. It is indicated that this exceptional situation relates to chemical structures of VOCs. Their chemical structures make the trend of the relation of VOCs degradation efficiency on the ionization potentials appear a deviation.

Photoelectrocatalytic activity of immobilized Fe2O3 photoelectrode for degradation of salicylic acid and methyl orange dye under visible light illumination

Fe2O3 thin films have been successfully synthesized by chemical spray pyrolysis technique. The effect of solution quantities onto the photoelectrochemical (PEC), structural, morphological, and optical properties has been studied. Film prepared at 50 ml solution quantity shows the maximum photoelectrochemical performance in 0.1 M NaOH electrolyte. X-ray diffraction studies reveal that the synthesized Fe2O3 thin films are polycrystalline with rhombohedral crystal structure. The surface morphology of Fe2O3 thin films shows that needle-shaped grains have slowly converted into round-shaped grains. The estimated band gap energy of Fe2O3 films varies from 2.02 to 2.15 eV with respect to quantities of spraying solution and it exhibits absorption in visible region. The photoelectrocatalytic degradation process shows better removal efficiency of organic compounds as compared to photocatalytic process for degradation of salicylic acid (SA) using large area (100 cm2) Fe2O3 photoelectrode under visible light illumination. Further, photoelectrocatalytic degradation process have been employed for degradation of colorant organic compound such as methyl orange (MO) dye.

Volatile Organic Compound Removal Efficiency of Green and Variegated Foliage Plants Grown under Different Light Intensities

Volatile Organic Compound Removal Efficiency of Green and Variegated Foliage Plants Grown under Different Light Intensities

The effect of temperature on the efficiency of industrial wastewater nitrification and its (geno)toxicity

AbstractThe paper deals with the problem of the determination of the effects of temperature on the efficiency of the nitrification process of industrial wastewater, as well as its toxicity to the test organisms. The study on nitrification efficiency was performed using wastewater from one of Polish chemical factories. The chemical factory produces nitrogen fertilizers and various chemicals. The investigated wastewater was taken from the influent to the industrial mechanical-biological wastewater treatment plant (WWTP). The WWTP guaranteed high removal efficiency of organic compounds defined as chemical oxygen demand (COD) but periodical failure of nitrification performance was noted in last years of the WWTP operation. The research aim was to establish the cause of recurring failures of nitrification process in the above mentioned WWTP. The tested wastewater was not acutely toxic to activated sludge microorganisms. However, the wastewater was genotoxic to activated sludge microorganisms and the genotoxicity was greater in winter than in spring time. Analysis of almost 3 years’ period of the WWTP operation data and laboratory batch tests showed that activated sludge from the WWTP under study is very sensitive to temperature changes and the nitrification efficiency collapses rapidly under 16°C. Additionally, it was calculated that in order to provide the stable nitrification, in winter period the sludge age (SRT) in the WWTP should be higher than 35 days.

Effects of pH on the Kinetics of Methyl Tertiary Butyl Ether Degradation by Oxidation Process (H2O2/Nano Zero-Valent Iron/Ultrasonic)

Background: In advanced oxidation processes, pH has a significant effect on the removal efficiency of organic compounds. This study examined the effect of pH changes on the removal efficiency and kinetics of methyl tertiary butyl ether (MTBE) concentration in aquatic environment. Objectives: The primary objective of this study was to evaluate the effect of pH changes on removal kinetics of the mentioned compound, using H2O2/nZVI (nano zero-valent iron)/ultrasonic process, and its impact on the reaction rate. Materials and Methods: In order to create the right conditions for oxidation, first of all iron nanoparticles combined with H2O2 oxidizer were synthesized, and then they were subjected to ultrasound waves and used in MTBE oxidation. In MTBE removal via H2O2/nZVI/Ultrasonic process, the effects of some parameters such as contact time (2 to 60 minutes), concentration of hydrogen peroxide (5 to 20 mL/L), concentrations of nZVI (0.15 to 0.45 g/L), MTBE concentrations (50 to 750 mg/L), and pH (2 to 9) were investigated. MTBE concentration analysis was performed using gas chromatography (GC). Results: According to this study, the best removal efficiency of 50 mg/L MTBE concentration in 89.56% under oxidation condition occurred when H2O2 level equals to 10 mL/L, nZVI is 0.25 g/L at pH 3.5. The results showed that the increase or decrease of pH from 3.5 results in a loss of oxidation efficiency as well as reduction in the amount of kap. In addition, the logarithmic changes curve of MTBE concentration showed that MTBE oxidation in H2O2/nZVI/ultrasonic method follows pseudo first order reactions. Conclusions: Changes of pH could remarkably affect the efficiency and oxidation rate of MTBE. In particular, the amount of kap in terms of oxidation declines substantially by moving away from the optimum pH range. In this study, pH 3.5 was considered as the optimal pH in H2O2/nZVI/ultrasonic oxidation process, with the elimination of about 89.56% of the high MTBE concentration. In general, we can say that by adjusting pH in this range, the rate and efficiency of MTBE oxidation can be enhanced in H2O2/nZVI/ultrasonic method.

Performance of Anaerobic Reactor in Attached and Suspended Growth Mechanisms for the Removal of Tofu Wastewater

This study assessed the removal efficiency of organic compounds in attached and suspended growth mechanisms when an anaerobic reactor was used to treat tofu wastewater. Parameters such as BOD (BiologicalOxygen Demand), TSS (Total Suspended Solid) and VSS (Volatile Suspended Solid) were measured. The assessments of removal efficiency were measuredby the amount of degradation of organic compounds caused by the microorganisms. The analyses were conducted for 14 days with a ratio of 40% air and 60% wastewater for the suspended growth mechanism. In attached growth, gravel served as the media at 30% from 60% of wastewater with 40% air. The removal efficiency of organic compounds measured as the decrease of BOD, TSS, and VSS - in suspended and attached growth. BOD in suspended growth decrease 5,55% while 76,46% in attached growth, TSS in suspended growth decrease 64,59% while increased 19,40% in attached growth, similar results occurred for VSS parameter decrease 2,04% while increased 31,53%. The increased result of TSS and VSS in attached growth caused of biofilm growth. In conclusion, BOD, TSS, and VSS decreased greater when the anaerobic treatment in attached growth was applied. 1

COMPOSITE VEGETABLE DEGRADATION AND ELECTRICITY GENERATION IN MICROBIAL FUEL CELL WITH ULTRASONIC PRETREATMENT

Vegetable waste was used as the fuel of a two-chamber microbial fuel cell (MFC) for simultaneous power recovery and waste degradation. Effects of ultrasonic pretreatment, organic loadings, anolyte pH adjustment on the MFC performance were investigated. Results showed that higher power generation and organic compounds removal efficiency were achieved in the MFCs with the vegetable waste pretreated with ultrasonication at >1.0W/mL compared to the un-pretreated control. A maximum voltage of 491 mV (1000 external resistor), power density of 10.19 W/m3 and 7-d TCOD removal rate of 62.5% were attained for the ultrasonic pretreated samples, while the corresponding parts for the un-pretreated control were 430 mV, 5.96 W/m3 and 35.1%, respectively. For stable power generation and effective removal of the waste in the MFC system, the raw waste required a certain dilution and the anode solution should be adjusted to improve system buffering capacity.

Micelle swelling agent derived cavities for increasing hydrophobic organic compound removal efficiency by mesoporous micelle@silica hybrid materials

Mesoporous micelle@silica hybrid materials with 2D hexagonal mesostructures were synthesized as reusable sorbents for hydrophobic organic compounds (HOCs) removal by a facile one-step aqueous solution synthesis using 3-(trimethoxysily)propyl-octadecyldimethyl-ammonium chloride (TPODAC) as a structure directing agent. The mesopores were generated by adding micelle swelling agent, 1,3,5-trimethyl benzene, during the synthesis and removing it afterward, which was demonstrated to greatly increase the HOC removal efficiency. In this material, TPODAC surfactant is directly anchored on the pore surface of mesoporous silica viaSiOSi covalent bond after the synthesis due to its reactive Si(OCH3)3 head group, and thus makes the synthesized materials can be easily regenerated for reuse. The obtained materials show great potential in water treatment as pollutants sorbents.

Testing the usability of sea mussel ( Mytilus sp.) for the improvement of seawater quality—An experimental study

The aim of the present study has been to analyze the effect of Mytilus sp. on the quality of raw seawater (organic compounds and heavy metals concentrations). The experiment was conducted under laboratory conditions. Two groups of the sea mussel were used in the experiments: small (S group; mean shell length 28.54 ± 1.69 mm) and large ones (L group; mean shell length 35.07 ± 1.83 mm). The highest removal efficiency of organic compounds, Zn, Pb and Ni was observed for the water retention time in a reactor of 9 or 12 h. The differences between removal efficiencies of COD, Zn, Pb and Ni were significant and mainly dependent on the water retention time, less – on the mussels’ size (two-way ANOVA, p < 0.05). Unlike the other examined heavy metals, Cr revealed no significant concentration changes, which may suggest that sea mussels are unable to remove Cr from seawater quickly. The results suggest that it might be possible to use Mytilus sp. as a kind of biofilter for the improvement of seawater quality.

A Comparison of the Technological Effectiveness of Dairy Wastewater Treatment in Anaerobic UASB Reactor and Anaerobic Reactor With an Innovative Design

The present research was an investigation of the influence of an innovative design of reactor filled with polyethylene (PE) granulate on model dairy wastewater treatment efficiency under anaerobic conditions compared to that obtained in a typical UASB reactor. The experiment was conducted at laboratory scale. An innovative reactor was designed with the reaction chamber inclined 30° in relation to the ground with upward waste flow and was filled with PE granular material. Raw model dairy wastewater was fed to two anaerobic reactors of different design at the organic loading rate of 4 kg COD m-3 d-1. Throughout the experiment, a higher removal efficiency of organic compounds was observed in the reactor with an innovative design and it was higher by 7.1% on average than in the UASB reactor. The total suspended solids was lower in the wastewater treated in the anaerobic reactor with the innovative design. Applying a PE granulated filling in the chamber of the innovative reactor contributed to an even distribution of sludge biomass in the reactor, reducing washout of anaerobic sludge biomass from the reaction chamber and giving a higher organic compounds removal efficiency.

Organic micropollutants degradation in ozone-loaded system with perfluorinated solvent

In order to provide higher ozonation process efficiency, new methods of advanced oxidation have been investigated. One of them is two-phase ozonation, sometimes called as ozone-loaded system. In this study, the solubility and stability of ozone in Fluorinet FC40 as well as the influence of pH and contact time on diffusion rate of oxidant from saturated FC40 phase to water was examined. The main purpose of this paper is to compare the removal efficiency of organic compounds with different distribution coefficient ( K D) in conventional and ozone-loaded systems as well as to reveal the mechanism of the process. It is shown that organic micropollutants with high K D diffuse into FC40 where degradation reaction takes place. In a case of compounds with high polarity the perfluorinated phase works as ozone reservoir. The results indicated that oxidant is gradually released from FC40 into the water. In consequence, the oxidation reaction occurs in water, not in perfluorinated phase as it has been so far presumed.