Utilization of nickel-graphite electrode as an electron donor for high-efficient microbial removal of solved U(VI) mediated by Leifsonia sp.

Enzymatically catalyzed reduction of metals by bacteria has potential application value to uranium-mine wastewater. However, its practical implementation has long been restricted by its intrinsic drawbacks such as low efficiency and long treatment-time. This study aims to explore the effect of electrodes on U (VI) removal efficiency by a purified indigenous bacteria isolated from a uranium mining waste pile in China. The effects of current intensity, pH, initial U (Ⅵ) concentration, initial dosage of bacteria and contact time on U (Ⅵ) removal efficiency were investigated via static experiments. The results show that U(VI) removal rate was stabilized above 90% and the contact time sharply shortened within 1 h when utilized nickel-graphite electrode as an electron donor. Over the treatment ranges investigated maximum removal of U (Ⅵ) was 96.04% when the direct current was 10 mA, pH was 5, initial U (Ⅵ) concentration was 10 mg/L, and dosage of Leifsonia sp. was 0.25 g/L. In addition, it is demonstrated that U (VI) adsorption by Leifsonia sp. is mainly chemisorption and/or reduction as the quasi-secondary kinetics is more suitable for fitting the process. FTIR results indicated that amino, amide, aldehyde and phosphate -containing groups played a role in the immobilization of U (VI) more or less. SEM and EDS measurements revealed that U appeared to be more obviously aggregated on the surface of cells. A plausible explanation for this, supported by XPS, is that U (VI) was partially reduced to U (IV) by direct current then precipitated on the cells surface. These observations reveal that Nickel-graphite electrode exhibited good electro-chemical properties and synergistic capacity with Leifsonia sp. which potentially provides a new avenue for uranium enhanced removal/immobilization by indigenous bacteria.

Occurrence and distribution of azole antifungal agents in eight urban Romanian waste water treatment plants.

Azole compounds are utilized to combat fungal infections in plants to protect them and also used for treating mycosis in humans. The LC-MS/MS method is a technique that combines liquid chromatography with tandem mass spectrometry for analysis of twelve azole compounds from wastewater (influent, effluent) and sewage sludge. The compounds were isolated from waste water using automatic extraction in the solid phase. Sludge samples were dried by lyophilization, after which they were subjected to ultrasound extraction with methanol. The quantification limits ranged from 0.3 ng/L (clotrimazole-CLO and prochloraz-PRO) to 1.5 ng/L (tetraconazole-TEB and penconazole-PEN), for wastewater samples and for sewage sludge, the LOQs ranged from 0.1 ng/g to 0.6 ng/g. High concentrations of climbazole-CLI (207-391 ng/L), tebuconazole (92-424 ng/L), and clotrimazole (6.9-93-ng/L) were observed in influent samples of the 8 urban wastewater treatment plants, followed by fluconazole (49.3-76.8 ng/L), and prochloraz (7.3-72 ng/L). The ∑Azoles had a maximum of 676 ng/L in the Galati effluent, followed by the Bucharest station 357 ng/L, and 345 ng/L in the Braila effluent. The highest value of the daily mass loading (input) level was observed for climbazole, 265 mg/day/1000 in Iasi station, followed by tebuconazole, 238 mg/day/1000 people in the Bucharest station, and 203 mg/day/1000 people for climbazole in the Targoviste station. The daily mass emission presented values between 0.7 and 247 mg/day/1000 people. The highest emissions were observed for climbazole, 247 mg/day/1000 people in Braila station; 174 mg/day/1000 people in the Iasi station and 129 mg/day/1000 people in the Bucharest station. The concentrations of climbazole detected in the effluent can present a high risk for the plants Lemna minor and Navicula pelliculosa. Clotrimazole may present a high risk to the plant Desmodesmus subspicatus and to the invertebrate Daphnia magna. PRO may present high risk to the invertebrate Mysidopsis Bahia.

Petroleum-contaminated soil bioremediation and microbial community succession induced by application of co-pyrolysis biochar amendment: An investigation of performances and mechanisms.

This study aimed to remediate petroleum-contaminated soil using co-pyrolysis biochar derived from rice husk and cellulose. Rice husk and cellulose were mixed in various weight ratios (0:1, 1:0, 1:1, 1:3 and 3:1) and pyrolyzed under 500 °C. These biochar variants were labeled as R0C1, R1C0, R1C1, R1C3 and R3C1, respectively. Notably, the specific surface area and carbon content of the co- pyrolysis biochar increased, potentially promoting the growth and colonization of soil microorganisms. On the 60th day, the microbial control group achieved a 46.69% removal of pollutants, while the addition of R0C1, R1C0, R1C3, R1C1 and R3C1 resulted in removals of 70.56%, 67.01%, 67.62%, 68.74% and 67.30%, respectively. In contrast, the highest efficiency observed in the abiotic treatment group was only 24.12%. This suggested that the removal of petroleum pollutants was an outcome of the collaborative influence of co-pyrolysis biochar and soil microorganisms. Furthermore, the abundance of Proteobacteria, renowned for its petroleum degradation capability, obviously increased in the treatment group with the addition of co-pyrolysis biochar. This demonstrated that co-pyrolysis biochar could notably stimulate the growth of functionally associated microorganisms. This research confirmed the promising application of co-pyrolysis biochar in the remediation of petroleum-contaminated soil.

Long-term phosphorus removal by Ca and Fe-rich drainage filter materials under variable flow and inlet concentrations.

Phosphorus (P) losses from tile-drained agricultural fields may degrade surface water quality by accelerating eutrophication. Among the different edge-of-field technologies, compact filter systems using different filter materials have been identified as potentially effective solutions for removing P from drainage water before discharge downstream. This study investigated the long-term (>696 days) P removal efficiency of 5 different filter materials in a column setup, using artificial drainage water (pH 6). Filter materials included two iron-based granulates (calcinated diatomaceous earth (CDE), ferric hydroxide granules (CFH)), and three calcium-based granulates (seashells, limestone, calcinated silicate/calcium oxide (Filtralite-P)). Experiments were performed under variable flow rates (0.037 and 1.52 L h-1; hydraulic retention time of 26-43 min and 18-30 h) and inlet P concentrations (0.14 and 0.7 mg L-1). An overall analysis revealed that the Fe-based materials achieved higher P retention than Ca-based materials. In particular, CFH was capable of retaining 99 and 98 % of the high and low inlet P concentrations, respectively. Conversely, limestone retained only 25 % of the high P load. CDE performed moderately well, independently of the inlet P concentration. Filtralite-P and Seashells performed well at high inlet P concentration but relatively poorly at low P concentration. The sensitivity of filter material P removal efficiency to variations in P loading was generally lowest for CFH and highest for limestone.

Application of Iron Nanoparticles Synthesized from a Bioflocculant Produced by Yeast Strain Pichia kudriavzevii Obtained from Kombucha Tea SCOBY in the Treatment of Wastewater.

Studying the production of Iron (Fe) nanoparticles using natural substances is an intriguing area of research in nanotechnology, as these nanoparticles possess biocompatibility and natural stability, which make them useful for a variety of industrial applications. The study utilized Fe nanoparticles that were synthesized using a bioflocculant and applied to eliminate different kinds of pollutants and dyes found in wastewater and solutions. The study involved the generation of Fe nanoparticles through a bioflocculant obtained from Pichia kudriavzevii, which were evaluated for their flocculation and antimicrobial capabilities. The impact of the Fe nanoparticles on human embryonic kidney (HEK 293) cell lines was studied to assess their potential cytotoxicity effects. An array of spectroscopic and microscopic methods was employed to characterize the biosynthesized Fe nanoparticles, including SEM-EDX, FT-IR, TEM, XRD, UV-vis, and TGA. A highly efficient flocculating activity of 85% was achieved with 0.6 mg/mL dosage of Fe nanoparticles. The biosynthesized Fe nanoparticles demonstrated a noteworthy concentration-dependent cytotoxicity effect on HEK 293 cell lines with the highest concentration used resulting in 34% cell survival. The Fe nanoparticles exhibited strong antimicrobial properties against a variety of evaluated Gram-positive and Gram-negative microorganisms. The efficiency of removing dyes by the nanoparticles was found to be higher than 65% for the tested dyes, with the highest being 93% for safranine. The Fe nanoparticles demonstrated remarkable efficiency in removing various pollutants from wastewater. In comparison to traditional flocculants and the bioflocculant, biosynthesized Fe nanoparticles possess significant potential for eliminating both biological oxygen demand (BOD) and chemical oxygen demand (COD) from wastewater samples treated. Hence, the Fe nanoparticles synthesized in this way have the potential to substitute chemical flocculants in the treatment of wastewater.

Removal efficiencies of microplastics of the three largest drinking water treatment plants in Bangladesh.

Drinking water treatment plants (DWTPs) are intended to provide safe water to the municipality, typically by treating surface waters from rivers, lakes, and streams. Regrettably, all of these water sources for DWTPs have been reported to be contaminated by microplastics (MPs). Hence, there is an urgent need to investigate the removal efficiencies of MPs from raw waters in the conventional DWTPs anticipating public health concerns. In this experiment, MPs in the raw and treated waters of the three major DWTPs of Bangladesh, having different water treatment processes, were evaluated. The concentrations of MPs in the inlet points of Saidabad Water Treatment Plant phase-1 and 2 (SWTP-1 and SWTP-2), which share a similar water source of the Shitalakshya River, were 25.7 ± 9.8 and 26.01 ± 9.8 items L-1. The third plant, Padma Water Treatment Plant (PWTP) utilizes water from the Padma River and had an initial MP concentration of 6.2 ± 1.6 items L-1. The studied DWTPs, with their existing treatment processes, were found to reduce the MP loads substantially. The final MP concentrations in treated waters of SWTP-1, SWTP-2, and PWTP were 0.3 ± 0.03, 0.4 ± 0.01, and 0.05 ± 0.02 items L-1 with the removal efficiencies of 98.8, 98.5, and 99.2 %, respectively. The considered size range of MP was 20 µm to <5000. Fragments and fibers were the two predominant MP shapes. In terms of polymer, the MPs were polypropylene (PP, 48 %), polyethylene (PE, 35 %), polyethylene terephthalate (PET, 11 %), and polystyrene (PS, 6 %). The field emission scanning electron microscopy-energy dispersive X-ray spectroscopy (FESEM-EDX) revealed the fractured and rough surfaces of the remaining MPs, which were also found to be contaminated with heavy metals, like lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As), copper (Cu), and zinc (Zn). Hence, additional initiatives are required to remove the residual MPs from the treated waters to safeguard the city dwellers from potential hazards.

Supplementation of 5-deoxystrigol for higher pollutant removal and biogas quality improvement by different microalgae-based technologies.

The treatment of biogas slurry by microalgae technology has the characteristics of low cost, environmental protection, and high efficiency. In this paper, the effects of four microalgae technologies, namely, monoculture of Scenedesmus obliquus (S. obliquus), co-culture of S. obliquus-activated sludge, co-culture of S. obliquus-Ganoderma lucidum (G. lucidum), and co-culture of S. obliquus-G. lucidum-activated sludge, on the treatment of biogas slurry were investigated. In addition, the effects of 5-deoxystrigol (5-DS) concentration and mixed light wavelengths (red-blue light intensity ratio) on nutrient removal and biogas upgrading were also investigated. The results showed that 5-DS significantly promoted the growth and photosynthetic performance of the microalgal system. The best purification performance could be achieved by co-cultivation of S. obliquus-G. lucidum-activated sludge when the 5-DS concentration was 10-11  M, and the red-blue light intensity ratio was 5:5 (225:225 µmol m-2  s-1 ). The maximum average removal efficiencies for chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), and carbon dioxide (CO2 ) were 83.25 ± 7.87%, 83.62 ± 7.78%, 84.19 ± 8.25%, and 71.68 ± 6.73%, respectively. The co-culture technology of S. obliquus-G. lucidum-activated sludge had great potential and superiority in removing nutrients from biogas slurry and upgrading biogas at the same time. The results of this study will provide a reference for the simultaneous purification of wastewater and upgrading of biogas using microalgae technology. PRACTITIONER POINTS: S. obliquus-G. lucidum-activated sludge consortium showed the best removal performance. 10-11 M 5-DS greatly promoted the purification performance. Removal efficiencies of COD, TN, and TP were more than 83%.

Factors impacting the behavior of phytoremediation in pesticide-contaminated environment: A meta-analysis.

Phytoremediation provides substantial advantages, including eco-friendliness, cost-effectiveness, efficiency, and visual appeal. However, the current knowledge of the factors influencing phytoremediation in pesticide-contaminated environments remains limited. It is critical to understand phytoremediation and the factors affecting the variation in removal efficiency. In this study, we compiled 72 previous research articles to quantify plant-induced improvements in removal efficiency and identify factors that influence variations in phytoremediation behavior through meta-analysis. We observed a significant increase in the removal efficiency of phytoremediation compared to the control group which did not involve phytoremediation. Pesticides significantly affect removal efficiency in terms of their modes of action, substance group, and properties. Plants demonstrated higher efficiency in remediating environments contaminated with pesticides possessing lower molecular masses and log Kow values. Plant species emerged as a crucial determinant of variations in removal efficiency. Annual plants exhibited a 1.45-fold higher removal efficiency than perennial plants. The removal efficiencies of different plant types decreased in the following order: agri-food crops > aquatic macrophytes > turfgrasses > medicinal plants > forage crops > woody trees. The Gramineae family, which was the most prevalent, demonstrated a robust and consistent phytoremediation ability. This study offers a more comprehensive triangular relationship between removal efficiency, pesticides, and plants, expanding the traditional linear model. Our findings offer valuable insights into the behavior of phytoremediation in pesticide-contaminated environments and the factors determining its success, ultimately guiding further research toward developing strategies for higher removal efficiency in phytoremediation.

Spatial Distribution and Risk Assessment of Antibiotics in 15 Pharmaceutical Plants in the Pearl River Delta.

Pharmaceutical plants are an essential source of antibiotics emitted into the aqueous environment. The monitoring of target antibiotics in pharmaceutical plants through various regions is vital to optimize contaminant release. The occurrence, distribution, removal, and ecological risk of 30 kinds of selected antibiotics in 15 pharmaceutical plants in the Pearl River Delta (PRD) were investigated in this study. Lincomycin (LIN) showed the highest concentration (up to 56,258.3 ng/L) in the pharmaceutical plant influents from Zhongshan city. Norfloxacin (NFX) showed a higher detection frequency than other antibiotics. In addition, the spatial distribution of antibiotics in pharmaceutical plants showed significant differences, with higher concentrations of total antibiotics found in pharmaceutical plant influents in Shenzhen City than those of different regions in PRD. The treatment processes adopted by pharmaceutical plants were commonly ineffective in removing antibiotics, with only 26.7% of antibiotics being effectively removed (average removal greater than 70%), while 55.6% of antibiotics had removal rates of below 60%. The anaerobic/anoxic/oxic (AAO)-membrane bioreactor (MBR) combined process exhibited better treatment performance than the single treatment process. Sulfamethoxazole (SMX), ofloxacin (OFL), erythromycin-H2O (ETM-H2O), sulfadiazine (SDZ), sulfamethazine (SMZ), norfloxacin (NFX), and ciprofloxacin (CIP) in pharmaceutical plant effluents posed high or moderate ecological risk and deserve particular attention.

Optimisation of operating conditions during coagulation-flocculation process in industrial wastewater treatment using Hylocereus undatus foliage through response surface methodology.

In exploring the application of natural coagulants in industrial wastewater treatment, plant-based coagulants have been gaining more interests due to their potential such as biodegradability and easy availability. Hylocereus undatus foliage as a plant-based coagulant has been proven to be efficient during the coagulation-flocculation process; however, limited research has been reported focusing only on palm oil mill effluent (POME) and latex concentrate wastewater. In addition, no previous study has been carried out to determine the performance evaluation of Hylocereus undatus foliage in treating different types of wastewater incorporating different operating conditions using optimization techniques. Hence, this study employed response surface methodology (RSM) in an attempt to determine the performance evaluation of the coagulant in paint wastewater treatment. Four independent factors such as the pH value, coagulant dosage, rapid mixing speed and temperature were chosen as the operating conditions. Three water parameters such as turbidity, chemical oxygen demand (COD) and suspended solids (SS) were chosen as responses in this study. Results revealed that through central composite design (CCD) via Design Expert software, the optimum conditions were achieved at pH 5, coagulant dosage of 300 mg/L, rapid mixing speed of 120 rpm and temperature at 30 °C. The experimental data was observed to be close to the model predictions with the optimum turbidity, COD and SS removal efficiencies found to be at 62.81%, 59.57% and 57.23%, respectively.

Natural wetlands contribution on phosphorus removal in small northern communities in Canada.

This study focuses on understanding the role of passive wastewater treatment (wastewater lagoon plus wetland) in reducing the phosphorus discharge levels in a northern small community in Manitoba, Canada. The facultative lagoon system of that small community treats domestic wastewater and seasonally discharges effluent into a wetland that connects to Lake Manitoba. This research assesses phosphorus removal efficiency through the natural wetland during the vegetation growing season. The average total phosphorus (TP) concentration reduction for the observed treatment area of 1.3 ha was more than 70%, achieving the desired TP discharge concentration below 1 mg/L. Data analysis showed that the main accumulation of TP occurred at the 21-40 cm soil depth, which indicates the potential of natural wetland treatment applications under cold continental climate conditions as an effluent polishing step to satisfy regulatory requirements for phosphorus reduction.

Effect of GR24 concentrations on tetracycline and nutrient removal from biogas slurry by different microalgae-based technologies.

A biogas slurry composed of carbon, nitrogen, phosphorus, and antibiotics was generated. Investigations into the nutrient and tetracycline removal performance of four microalgae-based contaminant removal technologies, including Chlorella vulgaris, C. vulgaris co-cultured with endophytic bacteria, C. vulgaris co-cultured with Ganoderma lucidum, and C. vulgaris co-cultured with G. lucidum and endophytic bacteria, were conducted. The algal-bacterial-fungal consortium with 10-9 M strigolactone (GR24) yielded the maximum growth rate and average daily yield for algae at 0.325 ± 0.03 d-1 and 0.192 ± 0.02 g L-1 d-1, respectively. The highest nutrient/ tetracycline removal efficiencies were 83.28 ± 7.95 % for chemical oxygen demand (COD), 82.62 ± 7.97 % for total nitrogen (TN), 85.15 ± 8.26 % for total phosphorus (TP) and 83.92 ± 7.65 % for tetracycline. Adding an algal-bacterial-fungal consortium with an optimal synthetic analog GR24 concentration is seemingly an encouraging strategy for enhancing pollutant removal by algae, possibly overcoming the challenges of eutrophication and antibiotic pollution.

Performance of a Tower-Shaped Integrated Ecological Purification Device for Pollutants Removal from Domestic Sewage in Rural Areas.

With the continuous development of China's modern economy and agricultural society, the discharge of rural sewage has been recognized as a major threat to the safety of the rural ecological environment. This study discussed the purification efficiency of a tower-shaped integrated ecological purification device (TIEPD)-consisting of a measuring tank, detention tank and three-stage purification unit-towards various common pollutants in rural areas during operation and tested the stability and efficiency of the TIEPD under different rural life events (fair activity days and nonfair activity days) and different precipitation intensities (light rain, moderate rain and heavy rain). The results showed that the average removal efficiencies of the TIEPD towards chemical oxygen demand, ammonia nitrogen, total nitrogen and total phosphorus were 69%, 67%, 54% and 73%, respectively. The average effluent concentration of each pollutant can meet the standard of the discharge of pollutants in China. The system exhibited good stability in removing pollutants and good ecological and economic benefits. This study provides the treatment of domestic sewage in the upper reaches of the Yangtze River and in mountainous areas of China and strengthens the prevention and control of rural nonpoint source pollution.

Removal effects of aquatic plants on high-concentration phosphorus in wastewater during summer.

Aquatic plants are widely used in depth treatment of wastewater; however, the phosphorus (P) removal mechanisms of aquatic plants at high temperatures in summer are not well understood. Eight aquatic plants, including two floating species (Ludwigia peploides and Hydrocharis dubia) and six emergent species (Lythrum salicaria, Sagittaria sagittifolia, Canna indica, Sparganium stoloniferum, Rotala rotundifolia, and Ludwigia ovalis), were treated with five P solutions (3.0, 3.5, 4.0, 4.5, and 5.5 mg L-1) for 5 weeks in a greenhouse during summer at air temperatures ranging from 25 to 35 °C. H. dubia, L. peploides, L. salicaria, and S. sagittifolia showed high water P removal efficiencies (exceeded 95%). Furthermore, their corresponding residual P concentrations in water were almost lower than the limit value of 0.2 mg L-1 of Grade III in the Chinese Environmental Quality Atandards for Surface Water (GB3838-2002). Plants have different water P removal paths. For example, H. dubia enriched more P with water P concentration increasing significantly. As the culture time increased, the water pH fluctuated significantly in the fall, and then H. dubia used the produced H+ enrich P. L. peploides did not enrich P, but proliferated rapidly, to remove P from water by increasing its fresh weight (FW). L. salicaria and S. sagittifolia showed two paths of enrich-P and FW increase. During the growth process of L. salicaria, the stem diameter and leaf length increased with an increase in P concentration in water or plant or both; however, the height and root length of L. peploides were reduced. Moreover, SOD and CAT activities responded to high P concentrations in water or high temperatures or both, which protected against oxidative damage. These findings could offer theoretical foundation and practical guidance for selection of aquatic plant species in depth treatment of wastewater during summer.

Novel ecological ditch system for nutrient removal from farmland drainage in plain area: Performance and mechanism.

The loading of nitrogen (N) and phosphorus (P) from agricultural drainage as the non-point sources is a worldwide environmental issue for aquatic ecosystem. However, how to remove these nutrients effectively from agricultural drainage remains a big challenge with increasing cemented ditches for better management. Here, we designed a novel ecological ditch system which integrated an earth ditch and a cemented ditch with iron-loaded biochar in the Chengdu Plain to reduce the loss of N and P from farmland. After a two-year monitoring, the removal efficiency of total N and total P reached 24.9% and 36.1% by the earth ditch and 30.7% and 57.8% by the integrated ditch system, respectively. The water quality was evidently improved after passing through the ditch system with the marked decrease in the concentrations of N and P. Dissolved organic N, nitrate, and particulate P became the dominant fractions of N and P loss. Rainfall soon after fertilization increased the concentrations of N and P in the ditch system and markedly affected their removal efficiency. The iron-loaded biochar effectively removed N and P from the drainage, especially at the high concentrations, which was mainly attributed to its high adsorption of the dissolved N and P fractions and the interception of the particulate nutrients. Our results indicate that the designed ecological ditch system has a high potential for alleviating agricultural non-point source pollution in the plain area and can be extended to other lowland agricultural ecosystems.

Enhanced oil removal from oily sand by injecting micro-macrobubbles in swirl elution.

Environmental contamination by petroleum hydrocarbons was exacerbated by oil pipeline breaks, marine oil spills and discharges from industrial production. To further improve the removal performance of petroleum hydrocarbons in solid particles, the deoiling experiments of swirl elution with micro-macrobubbles on oily sands were carried out in this paper. Experiment results indicated that when particles fell from the center of the bubble, the collision efficiency was 99.3%. The instantaneous contact angle (ICA) between the macrobubbles and the oil layer was improved in the presence of microbubbles. Furthermore, the maximum ICA of bubbles attaching to the oil layer was found to occur at pH 9 in the system of oily sand mixtures ranging from pH 5 to pH 14. This finding indicated that the slightly alkaline solution was more advantageous for bubbles to attach to the oil layer than the highly alkaline solution. The optimum condition for the elution of oily sand in the mixture of pH 7-14 was pH 12, and the oil removal efficiency was 85.4% for 10 min. The oil removal efficiency of swirl elution (SE) with bubbles on oily sand at pH 12 for 10 min was superior to either SE without bubbles or air flotation (AF). The results show that the swirl elution with bubbles can effectively enhance the oil removal efficiency of oily sands and provide guidance for controlling the environmental petroleum hydrocarbon contamination and reducing the usage of surfactants.

High-concentration COD wastewater treatment with simultaneous removal of nitrogen and phosphorus by a novel Candida tropicalis strain: Removal capability and mechanism.

Aerobic and anaerobic continuous stirred-tank reactor (CSTR), up-flow anaerobic sludge blanket (UASB) were set up and inoculated with newly isolated Candida tropicalis. Reactors were operated at high concentrations of chemical oxygen demand (COD) (8000 mg/L), the modified UASB expressed better COD removal rate simultaneously removal of nitrogen and phosphate than other two reactors. Notably, under both aerobic or anaerobic conditions, large amounts of organic acids and alcohol were generated. Transcriptomic analysis showed that carbon metabolism under anaerobic conditions shared the same pathway with aerobic conditions by regulating and inhibiting some functional genes. Experiments utilizing different carbon sources proved that our strain has excellent performances in utilizing organic materials, which were verified by transcriptomic analysis. Finally, the strain was applied to treat four types of sugar-containing wastewaters. Among them, our strain exerts the best removal capability of COD (90%), nitrogen (89%), and phosphate (82%) for brewery wastewater.

Effect of aniline and antimony on anaerobic-anoxic-oxic system with novel amidoxime-modified polyacrylonitrile adsorbent for wastewater treatment.

There has been increasing concern over the mixed discharge of municipal-textile composite wastewater, which remains challenging for typical wastewater treatment plant (WWTP) using anaerobic-anoxic-oxic process (AAO). Highly-toxic aniline and antimony, typical co-contaminants in textile wastewater, usually lead to increased chemical oxygen demand (COD) in influent and deteriorated effluent quality. Amidoxime-modified polyacrylonitrile (amPAN) adsorbent was prepared and added to adsorb antimony and facilitate substrate removal. With amPAN dosage at 6.0 g L-1 in oxic bioreactor, 64.2 ± 5.6% of antimony was removed from influent. Extracellular polymeric substance release was simultaneously changed with residual antimony concentration. Meanwhile, amPAN promoted the proliferation of Proteobacteria, Bacteroidetes and Epsilonbacteraeota serving as microorganism carrier. As a result, removal efficiencies of COD (94.4 ± 0.6%), ammonium (NH4+-N, 92.6 ± 3.3%), total nitrogen (TN, 76.4 ± 6.3%) and total phosphorus (TP, 93.4 ± 2.1%) were enhanced to meet Class 1A discharge standard in China. These results indicate that AAO with amPAN is promising for municipal-textile composite wastewater treatment.

Biodegradable chelant-metal complexes enhance cadmium phytoextraction efficiency of Solanum americanum.

Toxic contaminants (metals and metal-containing compounds) are accumulating in the environment at an astonishing rate and jeopardize human health. Remarkable industrial revolution and the spectacular economic growth are the prime causes for the release of such toxic contaminants in the environment. Cadmium (Cd) is ranked the 7th most toxic compound by the Agency for Toxic Substances and Disease Registry (USA), owing to its high carcinogenicity and non-biodegradability even at miniscule concentration. The present study assessed the efficiency of four biodegradable chelants [nitrilotriacetic acid (NTA), ethylenediamine disuccinate (EDDS), ethylene glycol tetraacetic acid (EGTA), and citric acid (CA)] and their dose (5 mM and 10 mM) in enhancing metal accumulation in Solanum americanum Mill. (grown under 24 mg Cd kg-1 soil) through morpho-physiological and metal extraction parameters. Significant variations were observed for most of the studied parameters in response to chelants and their doses. However, ratio of root and shoot length, and plant height stress tolerance index differed non-significantly. The potential of chelants to enhance Cd removal efficiency was in the order - EGTA (7.44%) > EDDS (6.05%) > NTA (4.12%) > CA (2.75%). EGTA and EDDS exhibited dose-dependent behavior for Cd extraction with 10 mM dose being more efficient than 5 mM dose. Structural equation model (SEM) depicted strong positive interaction of metal extraction parameters with chelants (Z-value = 11.61, p = 0.001). This study provides insights into the importance of selecting appropriate dose of biodegradable chelants for Cd extraction, as high chelant concentration might also result in phytotoxicity. In the future, phytoextraction potential of these chelants needs to be examined through field studies under natural environmental conditions.

Performance assessment of the indigenous ceramic UF membrane in bioreactor process for highly polluted tannery wastewater treatment.

The present study evaluates the performance of an indigenously developed ceramic ultrafiltration (UF) membrane in a lab-scale membrane bioreactor (MBR) process to treat real tannery effluent with varying organic loading (1500-6000 mg/L). UF membrane was prepared by the coating of bentonite clay on tubular clay-alumina macroporous support. The membrane surface was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, BET adsorption-desorption, contact angle measurement, and atomic force microscopy. In the side-stream MBR process, sewage sludge from a local sewage treatment plant was used as an activated sludge source with a constant sludge retention time of 30 days. Membrane filtration was performed in cross-flow mode using a single-channel membrane module. Artificial neural network (ANN) modeling tool was used to analyze the influence of various independent input variables, namely, the hydraulic retention time (4-10 h), mixed liquor suspended solid (MLSS) concentration (2-8 g/L), and influent COD concentration (1500-6000 mg/L) on COD removal (%) with feed-forward backpropagation method. Membrane study was done at a transmembrane pressure of 4.3 bar and feed flow rate of 7.5 L/min to observe the flux declination and fouling of the UF membrane with time. Average COD and BOD concentrations obtained in the treated effluent were 147.56 and 31 mg/L, respectively, and chromium concentration was < 0.1 mg/L; thus, treated effluent quality was found to be suitable for industrial recycling purposes apart from the safe environmental discharge. An in-depth study was undertaken to understand the removal mechanism in the MBR process, nature and extent of membrane fouling, changes in the morphology of the UF membrane, surface wettability, and surface topology by detailed surface characterization of the membrane pre- and post-filtration.