This study investigated bacterial communities during aerobic food waste co-composting degradation of highly PCDD/F-contaminated field soil. The total initial toxic equivalent quantity (TEQ) of the ...soil was 16,004 ng-TEQ kg−1 dry weight. After 42-day composting and bioactivity-enhanced monitored natural attenuation (MNA), the final compost product's TEQ reduced to 1916 ng-TEQ kg−1 dry weight (approximately 75% degradation) with a degradation rate of 136.33 ng-TEQ kg−1 day−1. Variations in bacterial communities and PCDD/F degraders were identified by next-generation sequencing (NGS). Thermophilic conditions of the co-composting process resulted in fewer observed bacteria and PCDD/F concentrations. Numerous organic compound degraders were identified by NGS, supporting the conclusion that PCDD/Fs were degraded during food waste co-composting. Bacterial communities of the composting process were defined by four phyla (Proteobacteria, Actinobacteria, Bacteroidetes and Firmicutes). At the genus level, Bacillus (Firmicutes) emerged as the most dominant phylotype. Further studies on specific roles of these bacterial strains are needed, especially for the thermophiles which contributed to the high degradation rate of the co-co-composting treatment's first 14 days.
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•Dioxin-contaminated field soil was remediated by food waste co-composting.•Dioxin degradation was approximately 75% and followed first-order kinetics.•Bacterial communities were studied using next generation sequencing.
•Total nitrogen removal rate achieved 0.011–0.020mg TN mgVSS−1d−1 for both MBRs.•A higher removal of antibiotics was found in FS than in HF.•Remarkable removal of antibiotics (CIP, NOR, OFL, TET, ...TRI, ERY) were achieved.•Sulfamethoxazole was not significantly removed in Sponge MBRs.•A significant reduction of membrane fouling was performed in HF-Sponge MBR.
Hollow fiber (HF) and flat sheet (FS) Sponge MBRs were operated at 10–20 LMH flux treating hospital wastewater. Simultaneous nitrification denitrification (SND) occurred considerably with TN removal rate of 0.011–0.020mg TN mgVSS−1d−1. Furthermore, there was a remarkable removal of antibiotics in both Sponge MBRs, namely Norfloxacin (93–99% (FS); 62–86% (HF)), Ofloxacin (73–93% (FS); 68–93% (HF)), Ciprofloxacin (76–93% (FS); 54–70% (HF)), Tetracycline (approximately 100% for both FS and HF) and Trimethoprim (60–97% (FS); 47–93% (HF). Whereas there was a quite high removal efficiency of Erythromycin in Sponge MBRs, with 67–78% (FS) and 22–48% (HF). Moreover, a slightly higher removal of antibiotics in FS than in HF achieved, with the removal rate being of 0.67–32.40 and 0.44–30.42µgmgVSS−1d−1, respectively. In addition, a significant reduction of membrane fouling of 2–50 times was achieved in HF-Sponge MBR for the flux range.
Abstract
In this article, we investigated the efficiency of a magnetic resonant wireless power transfer (MR-WPT) in conducting medium and found out an optimal frequency for designing the system. In ...conducting environment, the eddy current loss is generated by the high-frequency alternating currents in the coils. It is manifested by increased radiation resistance of resonator coil leads to decrease the quality factor (
Q
-factor), which reduces the wireless power transfer (WPT) efficiency in conducting medium. The
Q
-factor of the resonator coil strongly depending on the conductivity, frequency, and thickness of conducting block. Two MR-WPT systems operating at 10.0 MHz and 20.0 MHz are implemented to study the effect of conducting medium on efficiency. The achieved results indicated that the 20.0 MHz system has higher efficiency at a conductivity smaller than 6.0 S/m. However, at the larger conductivity, the 10.0 MHz system is more efficient. The results provide a method to determine the optimal frequency of a WPT system operating in the conducting medium with various conductivities and thickness blocks. This method can be used to design MR-WPT systems in numerous situations, such as autonomous underwater vehicles and medical implants.
Urine has been considered as an ideal nutrient source for microalgae cultivation thanks to its composition containing the high concentrations of nitrogen and phosphorus. Herein, the microalgae growth ...in urine was evaluated in a lab-scale membrane photobioreactor (MPBR) system. This work aimed to validate the influence of low biomass retention times (BRT) (10, 7, 5, 3, 2 d) on nutrient remediation and biomass productivity. It revealed that BRT of 7 d resulted in synergistically high biomass production (biomass productivity of 313 mg/L.d) and removal rates (TN of 90.5 mg/L.d and TP of 4.7 mg/L.d). Notably, the short BRT of 2–5 d was not sufficient to trigger actively growing microalgae and thus reduced biomass production rate. In addition, as operated at a low flux of 2 L/m2.h, MPBR system required no physical cleaning for 100 days of operation. The BRT-dependent biomass concentration played a pivotal role in changing the fouling rate of MPBR; however, the fouling is reversible in the MPBR system under the low flux condition.
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•A membrane photobioreactor was applied for nutrient capture from urine.•Urine was indeed a potential source for microalgae biomass production.•Biomass retention time (BRT) of 7 d was proposed for optimum operation.•Under BRT of 2–5 d, such a drastic decrease in biomass accumulation was noticed.•The BRT-dependent biomass accumulation governed the TN removal rate.
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•Hydrothermal treatment created good precursor for production of biochar.•Pore formation and enlarged surface area of biochar were obtained with ZnCl2.•The biochar showed superior ...tetracycline adsorption capacity (673.0 mg·g−1).
In this study, sunflower seed husk biochar prepared by ZnCl2-activated and hydrothermal carbonization (HZSF) was studied for its effectiveness in removing tetracycline (TC) from an aqueous solution. The physical and chemical properties of materials were characterized by different methods of surface analysis. The specific surface area of HZSF is significantly enhanced over 1200 times compared with non-modified biochar (HZSF: 1578.3 m2·g−1, SF-700: 1.3 m2·g−1), which has an enhancement effect on the TC adsorption capacity. The HZSF showed that the Langmuir isotherm and pseudo-second-order kinetic models could properly characterize the adsorption processes. In the Langmuir isotherm model, HZSF exhibited effective adsorption performance with qmax of 673.0 mg·g−1 at 298 K for 24 h. The possible mechanisms for the adsorption process were the monolayer, chemical adsorption, and the participation of strong intermolecular forces. In general, HZSF has the potential to be a useful adsorbent for the elimination of antibiotics from water-based solutions.
The human health risks caused by heavy metal contamination (As, Cd, Cr, Cu, Hg, Pb, Ni, and Zn) in the surface water of the Houjing River, the most contaminated river in southern Taiwan, were ...assessed in this study. Firstly, heavy metal contamination was evaluated by the contamination factors (CF) and the metal indexes (MI). Secondly, the human health risks due to heavy metal contamination were simulated using the Adaptive Risk Assessments Modeling System (ARAMS) through three scenarios; fish ingestion, dermal water contact, and incidental water ingestion during swimming. The hazard quotient (HQ) and the hazard index (HI) were used to evaluate non-carcinogenic risks, while carcinogenic risks were estimated by the lifetime cancer incidence risk index (CR) and the cumulative cancer risk (CCR). The results showed that the synergistic contamination of heavy metals in the surface water was severe (MI = 12.4), with the highest contribution from Cu, Ni, and Pb. Copper had the highest non-carcinogenic risk at the “adverse effect” level, while Ni and Cr had the highest carcinogenic risk at an “unacceptable” level. In addition, the cumulative risks of fish ingestion (HIFI = 6.75 and CCRFI = 1.25E-03) were significantly higher than those of the swimming scenarios (HI(DC + WI) = 1.94E-03 and CCR(DC + WI) = 9.32E-08). The results from this study will be beneficial for immediate and future contamination control measures and human health management plans for this study area. This study has also demonstrated the effectiveness of using ARAMS in human health risk assessment.
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•High heavy metal contamination in the Houjing River's surface water was reported.•Adaptive Risk Assessments Modeling System was effective in health risk assessment.•Copper and Nickel had the highest noncarcinogenic and carcinogenic risk, respectively.•Cumulative noncarcinogenic risk was classified as “adverse effect”.•Cumulative carcinogenic risk was classified as “unacceptable”.
Nitrogen removal is crucial in wastewater treatment process as excessive nitrogen content could result in eutrophication and degradation of aquatic ecosystems. Moreover, to satisfy the fast-growing ...need of fertilizers due to an increase in human population, recovering nitrogen from wastewater is of the most sustainable approach. Currently, the membrane technique integrated with biological processes namely bio-membrane based integrated system (BMIS) is a promising technology for recovering nitrogen from wastewater, including osmotic membrane bioreactors, bioelectrochemical systems and membrane photobioreactors. In this review study, the nitrogen recovery in different BMHSs, the role of operational parameters and the nitrogen recovery mechanism were discussed. Apart from this, the implementation of nitrogen recovery at pilot- and full-scale was summarized. Perspectives on the major challenges and recommendations of the BMIS for the nitrogen recovery in wastewater treatment were proposed, in which the integrated technologies and more scale-up studies regarding nitrogen recovery by the BMISs were also highlighted and recommended.
•The N recovery by bio-membrane based integrated systems (BMISs) was discussed.•Various configurations of BMISs for N recovery were reviewed.•Current implementation of N recovery at pilot/full-scale was summarized.•Perspective on BMISs for N recovery was given.•Integrated bio-membrane hybrid systems are promising for N recovery.
Agricultural wastes from cropping activities are always available with high production yield after containing organic-rich materials that can replace the commercial carbon-made components in the ...Microbial fuel cell (MFC) such as electrodes or catalysts. Although many studies reviewed the application of waste derived-biochar to develop a low-cost MFC, they solely discussed different functions of biochar and future research in the practically applying of the MFC. Toward the requirements of sustainable development goals regarding waste-to-energy practices, this work firstly overviews the selection of crop residues to produce biochar through different approaches and the electrochemical performance of products in MFC. Then, the context of negative CO2 emission technologies is considered following the integration of biochar as sustainable electrode materials for MFC and bioenergy with carbon capture, storage, and utilization. Finally, the application of circular economy will be discussed along with the perspectives and prospects of recent challenges, and recommendations for the future developments of agricultural waste derived-biochar as electrodes in the MFC. This review expectantly provides insight into using agricultural waste to support the sustainable development goals via MFC to adapt simultaneously water-food-energy and waste-to-energy issues.
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•Fabrication and characterization of biochars from agricultural wastes are reviewed.•Performance of waste-derived biochars as electrodes in the MFC is summarized.•Microbial activities and cost evaluation for biochar-based electrode are discussed.•Perspectives for biochar-MFC in achieving negative CO2 emissions are provided.
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•Ciprofloxacin affected treatment performance and fouling propensity of Sponge-MBR.•COD removal was 94–98% under the added CIP dosage less than 100 µg L−1.•High CIP dosages enhanced ...nitrification but significantly inhibited denitrification.•Floc size and membrane fouling decreased at high CIP dosages of 100–200 µg L−1.
This study aimed to evaluate treatment performance and membrane fouling of a lab-scale Sponge-MBR under the added ciprofloxacin (CIP) dosages (20; 50; 100 and 200 µg L−1) treating hospital wastewater. The results showed that Sponge-MBR exhibited effective removal of COD (94–98%) during the operation period despite increment of CIP concentrations from 20 to 200 µg L−1. The applied CIP dosage of 200 µg L−1 caused an inhibition of microorganisms in sponges, i.e. significant reduction of the attached biomass and a decrease in the size of suspended flocs. Moreover, this led to deteriorating the denitrification rate to 3–12% compared to 35% at the other lower CIP dosages. Importantly, Sponge-MBR reinforced the stability of CIP removal at various added CIP dosages (permeate of below 13 µg L−1). Additionally, the fouling rate at CIP dosage of 200 µg L−1 was 30.6 times lower compared to the control condition (no added CIP dosage).
Photobioreactor technology, especially bubble column configuration, employing microalgae cultivation (e.g., Chlorella sp.), is an ideal man-made environment to achieve sufficient microalgae biomass ...through its strictly operational control. Nutrients, typically N and P, are necessary elements in the cultivation process, which determine biomass yield and productivity. Specifically, N:P ratios have certain effects on microalgae's biomass growth. It is also attractive that microalgae can sequester CO2 by using that carbon source for photosynthesis and, subsequently, reducing CO2 emission. Therefore, this study aims to investigate the effect of N:P ratios on Chlorella sp.’s growth, and to study the dynamic of CO2 fixation in the bubble column photobioreactor. According to our results, N:P ratio of 15:1 could produce the highest biomass yield (3568 ± 158 mg L−1). The maximum algae concentration was 105 × 106 cells mL−1, receiving after 92 h. Chlorella sp. was also able to sequester CO2 at 28 ± 1.2%, while the specific growth rate and carbon fixation rate were observed at 0.064 h−1 and 68.9 ± 1.91 mg L−1 h−1, respectively. The types of carbon sources (e.g., organic and inorganic carbon) possessed potential impact on microalgae's cultivation.
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•Optimal N:P ratio for culturing Chlorella sp. was 15:1.•Highest biomass concentration achieved in photobioreactor was 3568 mg L−1.•Maximum specific growth rate of Chlorella sp. at optimal N:P ratio was 0.064 h−1.•Carbon sequestration efficiency and rate were 28% and 68.9 mg L−1 h−1.
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