Sesuvium portulacastrum-Mediated Removal of Nitrogen and Phosphorus Affected by Sulfadiazine in Aquaculture Wastewater

Plant-based removal of nitrogen (N) and phosphorus (P) from water bodies is an important method for remediation of aquaculture wastewater. In order to acquire knowledge as to how antibiotic residues in wastewater might affect the microbial community and plant uptake of N and P, this study investigated N and P removal by a coastal plant Sesuvium portulacastrum L. grown in aquaculture wastewater treated with 0, 1, 5, or 50 mg/L sulfonamide antibiotics (sulfadiazine, SD) for 28 days and compared the microbial community structure between the water and rhizosphere. Results showed that SD significantly decreased N removal rates from 87.5% to 22.1% and total P removal rates from 99.6% to 85.5%. Plant fresh weights, root numbers, and moisture contents as well as activities of some enzymes in leaves were also reduced. SD changed the microbial community structure in water, but the microbial community structure in the rhizosphere was less affected by SD. The microbial diversity in water was higher than that in the rhizosphere, indicating microbial community differences. Our results showed that the commonly used antibiotic, SD, in aquaculture can inhibit plant growth, change the structure of microbial community, and reduce the capacity of S. portulacastrum plants to remove N and P from wastewater, and also raised alarm about detrimental effects of antibiotic residues in phytoremediation of wastewater.

Wastewater Substrate Disinfection for Application of Synechococcus Elongatus PCC 7942 Cultivation as Tertiary Treatment

The cultivation of microalgae or/and cyanobacteria in nutrient-rich wastewaters presents a significant opportunity for enhancing sustainability of tertiary wastewater treatment processes via resources/energy recovery/production. However, maintaining a monoculture in wastewater-media constitutes a significant challenge to be addressed, as a plethora of antagonistic and predating microorganisms exist is such media. In this regard, the present work assesses the efficiency of the low-cost wastewater substrate disinfection techniques of filtration, use of NaClO, H2O2 or Fe(VI), in terms of antagonistic or/and predating microbial species growth inhibition in Synechococcus elongatus PCC 7942 cultivations. Nitrates and phosphates removal rates were also experimentally assessed. The results showed that filter thickness has a greater effect on disinfection efficiency than that of filter’s pore size. Furthermore, the disinfection efficiency of Fe(VI), which was produced on-site by electrosynthesis via a Fe0/Fe0 cell, was greater than that of NaClO and H2O2. Filtration at ≤ 1.2 µm pore size coupled with chemical disinfection leads to unhindered S7942 growth and efficient nitrates and phosphates removal rates, at dosages of CT ≥ 270 mg min L−1 for NaClO and CT ≥ 157 mg min L−1 for Fe(VI). The coagulation action of Fe(III) species that result from Fe(VI) reduction and the oxidation action of Fe(VI) can assist in turbidity, organic compounds and phosphorous removal from wastewater-media. Moreover, the residual iron species can assist in S7942 harvesting and may enhance photosynthesis rate. Thus, the utilization of wastewaters for S7942 cultivation as tertiary treatment seems a promising and novel alternative to common nutrient removal processes that can reduce environmental footprint and operational costs of wastewater treatment plants.

Treatment of Actual Winery Wastewater by Fenton-like Process: Optimization to Improve Organic Removal, Reduce Inorganic Sludge Production and Enhance Co-Treatment at Municipal Wastewater Treatment Facilities

Despite many wineries being equipped with onsite wastewater treatment, winery wastewater (WWW) co-treatment at municipal wastewater treatment plants (WWTPs) remains a common practice in wine-making regions. The complex and highly variable nature of WWW can result in negative impacts on WWTP operations, highlighting a need for improved co-treatment methods. In this paper, the feasibility of using the Fenton-like process to pre-treat WWW to enhance co-treatment at municipal WWTPs is assessed. First-stage pre-treatment of the WWW, in the form of dilution and settling or aerobic biological treatment, is used prior to the Fenton-like process. A three-factor BBD experimental design is used to identify optimal reaction time and initial H2O2 and Fe3+ concentrations. Chemical oxygen demand (COD) and total organic carbon (TOC) removal rates are not able to accurately reflect the extent of reaction. Additional trials identified solubilization of particulate COD and TOC, as well as samples handling requirements prior to analysis, as factors affecting the apparent COD and TOC removal rates. Inert suspended solids (ISS) generated during the sample handling process are found to be the response variable best suited to quantifying the extent of the Fenton-like reaction. Maximum ISS generation is observed at initial H2O2 and Fe3+ concentrations of 4000 mg/L and 325 mg/L, however, results suggest that optimal concentrations exceed these values. The impact of adding pre-treated WWW, with and without Fenton-like treatment, to municipal WWTPs’ primary clarifiers and aerobic bioreactors is also assessed via bench-scale trials. Challenges associated with co-treating WWW are found to remain despite the pre-treatment alternatives investigated, including negative impacts on simulated primary and secondary effluent quality. The Fenton-like AOP provides limited opportunity to optimize or enhance co-treatment at municipal WWTPs.

Fire Occurrence Mediates Small-Mammal Seed Removal of Native Tree Species in a Neotropical Savanna

Seed dispersal and predation are critical processes for plant recruitment which can be affected by fire events. We investigated community composition of small mammals in gallery forests with distinct burning histories (burned or not burned ∼3 years before) in the Cerrado (neotropical savanna). We evaluated the role of these animals as seed removers of six native tree species, potentially mediated by the occurrence of fire. We sampled four previously burned sites and four unburned ones. Seed removal was assessed using two exclusion treatments: exclusive access of small rodents and access of all seed-removing vertebrates. The previous burning changed the structural characteristics of the forests, increasing the density of the understory vegetation and herbaceous cover, which determined differences in species composition, richness, and abundance of small rodents (abundance in the burned forests was 1/6 of the abundance in the unburnt ones). Seed removal rates across the six species were reduced in burnt forests in both treatments and were higher for the “all vertebrates” treatment. Other vertebrates, larger than small rodents, played a significant role as seed removers for five of the six species. The effects of fire were consistent across species, but for the two species with the largest seeds (Hymenaea courbaril and Mauritia flexuosa) removal rates for both treatments were extremely low in the burned forests (≦5%). The observed decline in small rodent seed predation in the burned forests may have medium to long-term consequences on plant communities in gallery forests, potentially affecting community composition and species coexistence in these forests. Moreover, fire caused a sharp decline in seed removal by large mammals, indicating that the maintenance of dispersal services provided by these mammals (mainly the agouti Dasyprota azarae) for the large-seeded species may be jeopardized by the burning of gallery forests. This burning would also affect several small mammal species that occur in the surrounding typical savanna habitats but also use these forests. Fire events have been increasing in frequency and intensity because of human activities and climate changing. This current scenario poses a serious threat considering that these forests are fire-sensitive ecosystems within the Cerrado.

Characteristic Pollutants Purification Analysis of Modified Phosphogypsum Comprehensive Utilization

The waste product Phosphogypsum (PG) produces in phosphoric acid production processes. Its storage requires large amounts of land resources and exist serious environmental risks. In this work detailed experimental research was carried out to investigate the potential reuse of PG after calcination modification as a novel building material for cast-in-place concrete products. The calcination modification mechanism was studied and the environmental risk assessment of modified PG is presented. The calcination modification includes crystal phase transformation, removal of impurities and modifying the pH value. The calcination was carried out at 280℃ for 3-4 hours, where the resulting product is a pH value of 7.3, and the soluble fluorine and phosphorus removal rates reach up to 72.7% and 82.4% respectively. These removal rates meet the requirements of the national Phosphogypsum standard (GB/T 23456-2009). To ensure the environmental safety, ecological risk assessment methods for determining the leaching toxicity of the modified PG were employed. The toxicity of Ba and P elements in the modified PG products was assessed, as well as the leaching toxicity concentrations of all particular heavy metals, which were found well below the limits set by the national standards. All the results presented strongly suggest that the 280℃ modified PG presented here has excellent application potential as a raw component in building materials.

Accidental Epidural Catheter Removal Rates and Strength Required for Disconnection: a Retrospective Cohort and Experimental Study

Background: Epidural analgesia requires the use of epidural catheters, which are associated with certain risks such as accidental epidural catheter removal, including dislodgement and disconnection. Few studies have investigated accidental catheter removal rates and directly compared them among epidural connector types. This study aimed to examine the differences in accidental catheter removal rates associated with different catheter connector types and to experimentally determine the linear tensile strength required to induce disconnection in each connector type.Methods: This retrospective cohort study included adult patients who underwent elective surgery and received patient-controlled epidural analgesia between December 2019 and August 2020. Patients were divided into groups according to the type of catheter connection used: standard (old group), new standard (new group), and new standard with taping (taping group). Furthermore, we prepared 60 sets of epidural catheters and connectors comprising 20 sets for each of the old, new, and taping groups, and used the digital tension meter to measure the maximum tensile strength required to induce disconnection. A multinomial logistic regression analysis was used to examine risk factors for disconnection. The experimental study groups were compared using one-way analysis of variance.Results: The clinical study involved in 920 patients (360, 182, and 378 patients in the old, new, and taping group, respectively). Dislodgement rates were similar among the three groups. Disconnection was most likely to occur in the new group (5.5%) and least likely to occur in the taping group (0.3%) compared to the old group (1.9%). However, the new group was not a risk factor for disconnection. The experimental study identified tensile strengths of 12.41 N, 12.06 N, and 19.65 N in the old, new, and taping groups, respectively. Comparison tests showed a significant difference in the tensile strength required for disconnection between the new and taping groups but not between the new and old groups.Conclusions: These findings suggest that taping the catheter connector connection may reduce the risk of disconnection, and thereby help improve patient outcomes. Further studies are required to clarify other parameters that may affect patient safety in this context.

STMO-5 Utilization of intraoperative multimodal technologies [PET and 5-ALA] for treating glioblastoma

Background: We can improve prognosis of glioblastoma by using positron emission tomography (PET) scans to guide them in removing tumors, and intraoperative magnetic resonance imaging (IoMRI) and 5-aminolevulinic acid (5-ALA) for identifying residual tumors. Tau proteins are reported to accumulate in glioblastomas, so we compared the efficacy of their PET tracer, THK5351, against that of 11C-MET, 18F-FLT, and 18F-FMISO. Methods: Patients (n = 11) underwent scans between February 2020 and July 2021 for glioblastoma resection. Tumor-to-normal tissue accumulation ratio (TNR) and accumulation volumes of 4 PET tracers were evaluated. Following excisions, 5-ALA fluorescent evaluation was classified as strong, vague, or none. Residual tumor volumes and removal rates were determined using T1Gd assessments and PET tracers. IoMRI confirmed presence of residual tumors.Results: THK5351 had a TNR of 5.20, and its accumulated volume was greater than that of other tracers: 1.80 for 11C-MET, 1.72 for 18F-FLT, and 2.82 for 18F-FMISO. 5-ALA fluorescent evaluation was vague (n = 7) or none (n = 4); respective residual tumor volumes (mL) were 2.3 and 0.2 (T1Gd), 5.7 and 0.9 (11C-MET), 5.6 and 0.6 (18F-FLT), 1.3 and 0.4 (18F-FMISO), and 7 and 1.4 (THK5351); respective tumor removal rates (%) were 90.4 and 99.6 (T1Gd), 79.2 and 86.4 (11C-MET), 84.4 and 89.2 (18F-FLT), 94.3 and 94.4 (18F-FMISO), and 72.3 and 83.4 (THK5351). The excised tumor tissue was found in the area where only THK5351 was accumulated.Conclusions: THK5351 accumulated in glioblastomas to a greater degree than that of other tracers, making it useful for discriminating between healthy and malignant tissues.

Comparative Study on Refractory Gold Concentrate Kinetics and Mechanisms by Pilot Scale Batch and Continuous Bio-Oxidation

Most studies conducted have focused on the pulp density, Fe3+ concentration and sulfuric acid concentration, etc., of bio-oxidation, and few have reported on the influence of different bio-oxidation methods on kinetics. In this study, a comparative investigation on refractory gold concentrate by batch and continuous bio-oxidation was conducted, with the purpose of revealing the kinetics influence. The results showed that improving the removal rates of the gold-bearing pyrite (FeS2) and arsenopyrite (FeAsS) yielded the best results for increasing gold recovery. The removal rates of S, Fe and relative gold recovery linearly increased when compared to the second-order equation increase of the As removal rate in both batch and continuous bio-oxidation processes. The removal kinetics of S and Fe by continuous bio-oxidation was 12.02% and 12.17% per 24 h day, approximately 86.64% and 51.18% higher than batch bio-oxidation, respectively. The higher removal kinetics of continuous bio-oxidation resulted from a stepwise increase in microbe growth, a larger population and higher dissolved Fe3+ and H2SO4 concentration compared to a linear increase by batch bio-oxidation. The cyanidation gold recovery was as high as 94.71% after seven days of continuous bio-oxidation, with the gold concentrate sulfur removal rates of 83.83%; similar results will be achieved after 13 days by batch bio-oxidation. The 16sRNA sequencing showed seven more microbe cultures in the initial residue than Acid Mine Drainage (AMD) at genus level. The quantitative real-time Polymerase Chain Reaction (PCR) test showed the four main functional average microbe populations of Acidithiobacillus, Leptospirillum, Ferroplasma and Sulfobacillus in continuous bio-oxidation residue as 1.08 × 103 higher than in solution. The multi-microbes used in this study have higher bio-oxidation activity and performance in a highly acidic environment since some archaea co-exist and co-contribute.

Experimental and Simulation Analysis of Physical Water Model through Tracer Injection under Various Baffles and Turbulence Inhibitor Conditions for Developing the Fluid Flow Parameters and Inclusion Removal Rates in Tundish

Tundish is a critical part involved in the continuous casting process, which ensures the constant flow of liquid metal and with performing different functions. In odd-numbered multistrand tundish, the confirmation consistency of the fluid flow among all the strands is one of major concerns. In this study, five-strand tundish with a set of weirs and a baffle is utilized for investigation concerning fluid flow parameters and inclusion removal analysis. The simulation is carried out in ANSYS FLUENT 19.2 software through the defined numerical model, and the experimental analysis is performed on a scaled physical water model through tracer injection. Four different baffles are designed along with two different types of turbulence inhibiter for the tundish to enhance the fluid flow parameters and inclusion removal rates. The inclusion sizes were varied from 10 to 100 µm with a difference of 20 µm respectively for studying the inclusion removal rate concerning inclusion sizes. From the outcomes obtained like the residence time distribution (RTD) curves and others, it was concluded that the fourth baffle version with the first turbulence inhibiter, which are equipped in tundish version TV8 is the most beneficial tundish version for the enhancement in fluid flow and inclusion removal rates as compared to other tundish versions in this study.