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Artificial rain, a technology primarily used for drought relief, has recently been used for combating regional air pollution. However, there are limited available measurement data to confirm the effectiveness of this control practice. In this study, we summarize control theories and indirect but relevant observations/findings, including air pollutant reduction after natural rain events and roadside sprinkling. A brief review of artificial rain basics is also provided. Our work shows that artificial rain appears to be a promising management strategy for air pollution control. However, field measurements are needed to further assess the cost-effectiveness of the practice, as well as the other benefits or challenges it may create. [ABSTRACT FROM AUTHOR]

Makeup water constitutes a key component in the water management of microalgal cultivation systems. However, the effect of makeup water addition on microalgal growth remains largely unexplored. This study compared two deionized water addition intervals (1 day and 4 days) for their effect on the growth of Scenedesmus dimorphus (S. dimorphus hereafter) in 2000 mL Pyrex bottles under controlled conditions. Cell counts and dry algal biomass (DAB) were measured to characterize the microalgal growth rate. Water addition intervals impacted algal cell counts but had little effect on DAB. Adding makeup water every day resulted in a higher growth rate (8.80 ± 1.46 × 105 cells mL−1 day−1; p = 0.22, though) and an earlier occurrence of the peak cell count (day 9) than adding it every 4 days (6.95 ± 1.68 × 105 cells mL−1 day−1 and day 12, respectively). It is speculated that water loss over an extended period and the following makeup water addition posed stress on S. dimorphus. Surpassing the peak cell count, S. dimorphus continued to grow in DAB, resulting in an increased cell weight as a response to nutrient starvation. Optical density at 670 nm (OD670) was also measured. Its correlation with DAB was found to be affected by water addition intervals (R2 = 0.955 for 1 day and 0.794 for 4 days), possibly due to a water loss-induced change in chlorophyll a content. This study is expected to facilitate the makeup water management of photobioreactor and open pond cultivation systems. [ABSTRACT FROM AUTHOR]

Particulate matter (PM) represents an air quality management challenge for confined swine production systems. Due to the limited space and ventilation rate, PM can reach relatively high concentrations in swine barns. PM in swine barns possesses different physical, chemical, and biological characteristics than that in the atmosphere and other indoor environments. As a result, it exerts different environmental and health effects and creates some unique challenges regarding PM measurement and mitigation. Numerous research efforts have been made, generating massive data and information. However, relevant review reports are sporadic. This study aims to provide an updated comprehensive review of swine barn PM, focusing on publications since 1990. It covers various topics including PM characteristics, sources, measurement methods, and in-barn mitigation technologies. As PM in swine barns is primarily of biological origins, bioaerosols are reviewed in great detail. Relevant topics include bacterial/fungal counts, viruses, microbial community composition, antibiotic-resistant bacteria, antibiotic resistance genes, endotoxins, and (1→3)-β-D-glucans. For each topic, existing knowledge is summarized and discussed and knowledge gaps are identified. Overall, PM in swine barns is complicated in chemical and biological composition and highly variable in mass concentrations, size, and microbial abundance. Feed, feces, and skins constitute the major PM sources. Regarding in-barn PM mitigation, four technologies (oil/water sprinkling, ionization, alternation of feed and feeders, and recirculating air filtration) are dominant. However, none of them have been widely used in commercial barns. A collective discussion of major knowledge gaps and future research needs is offered at the end of the report. [ABSTRACT FROM AUTHOR]

The heavy metals, such as Cr(VI), Pb(II) and Cd(II), in aqueous solutions are toxic even at trace levels and have caused adverse health impacts on human beings. Hence the removal of these heavy metals from the aqueous environment is important to protect biodiversity, hydrosphere ecosystems, and human beings. In this study, magnetic Nickel-Ferrite Nanoparticles (NFNs) were synthesized by co-precipitation method and characterized using X-Ray Diffraction (XRD), Energy Dispersive Spectroscopy (EDS) and Field Emission Scanning Electronic Microscopy (FE-SEM) techniques in order to confirm the crystalline structure, composition and morphology of the NFN's, these were then used as adsorbent for the removal of Cr(VI), Pb(II) and Cd(II) from wastewater. The adsorption parameters under study were pH, dose and contact time. The values for optimum removal through batch-adsorption were investigated at different parameters (pH 3–7, dose: 10, 20, 30, 40 and 50 mg and contact time: 30, 60, 90, and 120 min). Removal efficiencies of Cr(VI), Pb(II) and Cd(II) were obtained 89%, 79% and 87% respectively under optimal conditions. It was found that the kinetics followed the pseudo second order model for the removal of heavy metals using Nickel ferrite nanoparticles. [ABSTRACT FROM AUTHOR]

Increased carbon dioxide (CO2) emissions from anthropogenic activities are a contributing factor to the growing global warming worldwide. The economical method to recover and effectively reuse CO2 is through adsorption and absorption. In this study, CO2 is absorbed into the solution of sodium hydroxide having various concentrations (0.01, 0.1, 0.5, 1.0, 3.0 and 5.0 N), and the impact of the solution pH on the various product formation was observed. The resultant products formed at different pH of the absorbing solution are sodium carbonate at pH 10, Trona at pH 9, and sodium hydrogen carbonate at pH 8. The products formed are confirmed through X-ray diffraction analysis. After pH optimization, the sodium hydrogen carbonate formed at pH 8 is converted into sodium formate through hydrogenation in the presence of nickel ferrite catalyst at 80 °C and atmospheric pressure. The sodium formate produced is then used as a precursor to synthesize formic acid upon simple reaction with sulfuric acid. A reaction % age yield of 79 ± 0.2% formic acid is noted. Condensed formic acid vapors are later analyzed, using a high performance liquid chromatography for the qualitative analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Solids and nutrients in raw swine wastewater were removed with 3-step pretreatment. • Better S. dimorphus growth was achieved in pretreated than raw swine wastewater. • Algal reactors showed no consistent wastewater treatment boost versus control. • Algae-rich solids harvested from pretreated wastewater contained 5.7% nitrogen. • S. dimorphus is unlikely a suitable microalgal species for phosphorus recovery. Scenedesmus dimorphus was cultivated in raw and pretreated swine wastewater (SW) with 6-L photobioreactors (PBRs) to investigate the effect of solid–liquid separation on algal growth. The same aerated PBRs containing no algae were used as control. Moderate COD and nitrogen removal from the SW was achieved with the algal PBRs. However, compared to the control reactors, they offered no consistent treatment boost. Improved algal growth occurred in the pretreated SW, as measured by maximum algal cell count (3202 ± 275 × 106 versus 2286 ± 589 × 106 cells L−1) and cell size. The enhanced algal growth in the pretreated SW resulted in relatively high nitrogen (5.7 %) and organic matter contents in the solids harvested at the end of cultivation experiments, with ∼25.6 % of nitrogen in the SW retained in the solids and ∼9.1 % absorbed by algae. The pretreatment also resulted in elevated phosphorus removal. This study is anticipated to foster the development of microalgae-based SW treatment processes. [ABSTRACT FROM AUTHOR]

The aim of present work was to isolate cellulose from cotton gin waste (CGW) and synthesis of carboxymethyl cellulose (CMC) from it. Scoured and bleached CGW was used to investigate the effects of temperature, reaction time, acid-base concentration on the physiology of the resultant cellulose polymer. The isolated cellulose from CGW was converted to CMC by etherification using sodium monochloroacetic acid and different sodium hydroxide (NaOH) concentrations (5–40 g/100 mL) were tested to get high quality product. The optimum condition for carboxymethylation was found to be 20 g/100 mL NaOH which provided the highest viscosity and degree of substitution (DS = 0.874). Isolated cellulose and CMC were characterized using Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). FT-IR analysis revealed that the produced cellulose was of very good quality. Furthermore, X-ray diffraction (XRD) analysis spotlighted crystalline nature of cellulose. SEM images showed rough structure of cellulose while that of the CMC had a smooth surface. This optimized method will be tested at pilot scale in collaboration with local industry. [ABSTRACT FROM AUTHOR]

The present study is focusing on the synthesis of biochar-based Poly Vinyl Alcohol (PVA) bound nanofibers through electrospinning and its CO 2 adsorption capacity. Poultry litter was used for synthesizing the biochar at 300–600 °C. Synthesized biochar and fibers were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Thermogravimetric Analysis (TGA), Fourier Transform Infrared (FT-IR), and X-Ray Diffraction (XRD) to find out its morphology, composition, mass loss, functional groups, and crystalline structure. Biochar prepared at 500 °C showed rich micro-porosity. The average diameter of the nanofibers was found at 579 nm and was thermally stable up to 300 °C. The adsorption parameters under study was temperature, contact time, amine treatment, and the effect of CO 2 concentration. An increasing trend was observed in adsorption capacity by increasing the contact time between the biochar nanofiber fabric and the gas and a reverse trend was prominent with increasing temperature. Keeping all other parameters constant, at 20 °C and 20 min contact time the adsorption capacity reached its maximum value of 426 mg/g. It was observed that for the same adsorption conditions the adsorption capacity of amine treated biochar-based nanofibers increased from 426 to 462 mg/g. The presence of amino groups on the surface of biochar was confirmed through FT-IR analysis. • Biochar was thermally derived from poultry litter biomass. • PVA based biochar nanofibers were found thermally stable up to 300 °C. • CO 2 adsorption on biochar nanofibers increases with contact time. • Amine treated biochar nanofibers showed increased CO 2 adsorption. [ABSTRACT FROM AUTHOR]

Pakistan, an agricultural country, raises 146.5 million commercial and domestic poultry birds, which generate around 544,831 tons of waste per year. This waste finds its final disposal in agricultural land as soil fertilizer or disposal site amendment. The usage of poultry litter for this purpose is uncontrolled, which results in environmental degradation such as emission of greenhouse gases, e.g., methane. However, alternative options such as thermochemical conversion of poultry litter can offer better solutions where this waste can be used as a low-cost carbon source for the synthesis of Multiwalled Carbon Nanotubes (MWCNTs). In this study, efforts were made to utilize this cheap and plentiful carbon source for the synthesis of CNTs in the presence of Ni/Mo/MgO as a catalyst, through pyrolysis. For a better yield of carbon product, the optimum ratio for the catalysts (Ni/Mo/MgO) was found to be 4:0.2:1. Furthermore, the process parameters were also optimized for better carbon yield. A good yield of CNTs resulted from a pyrolysis time of 12 min, a temperature of 825 °C, and a catalyst weight of 100 mg. The structure and morphology of the produced nanotubes were confirmed through X-ray Diffractometer (X-RD) and Scanning Electron Microscopy (SEM). The environmental application of the nanotubes was tested in a synthetic chromium solution in the lab using a batch experiment. Different experimental conditions (pH, adsorbent dosage, and contact time) were optimized to improve the adsorption of Cr (VI) by carbon nanotubes and a UV-Visible spectrophotometer was used at 540 nm to measure the absorbance of Cr (VI). The results showed that up to 81.83% of Cr (VI) removal was achieved by using 8 mg of CNTs at pH 3 with 400 rpm at 180 min of contact time. Thus, it was concluded that poultry litter can be a useful source for the synthesis of MWCNTs and thereby removal of Cr (VI) from industrial tanneries' wastewater. [ABSTRACT FROM AUTHOR]

Grasses have been used widely to remediate contaminants present in domestic wastewater, but leachate generated from municipal solid waste that usually contain some concentrations of heavy metals has never been reported to be treated with grasses, especially Rhodes grass. A series of experiments was performed to investigate the contaminant uptake from municipal solid waste leachate by Chloris gayana (Rhodes grass) grown in combination with two commonly available grass varieties namely Vetiveria zizanioides (Vetiver grass) and Pennisetum purpureum (Elephant grass). Leachate used for the experiments had high values for chemical oxygen demand (5 g/L), pH (8.5), electrical conductivity (9.0 mS/cm), nitrates (182.1 mg/L), phosphates 6.4 mg/L along with heavy metals i.e. copper, zinc and manganese. Different dilutions of leachate ranging from 0 to 100% were applied in batches and their result showed that collectively all the grasses reduced overall contaminant concentrations. These were reported for chemical oxygen demand, electrical conductivity, nitrates, and phosphates reduced up to 67, 94, 94, and 73%, respectively. Metals uptake by grasses also showed a significant decrease in applied dose i.e. zinc (97%), copper (89%), and manganese (89%). Plant analysis showed that all grasses showed preference to heavy metals uptake e.g. Rhodes grass favoured up taking zinc, Elephant grass for copper and Vetiver grass preferred manganese. Overall growth performance of Rhodes grass was better in dilute leachate, whereas in more concentrated leachate, Rhodes grass did not perform better and production of biomass decreased. In Vetiver grass, root and shoot lengths decreased with increasing leachate strength, but the biomass did not change significantly. [ABSTRACT FROM AUTHOR]

For its small square footage, a vertical bed biofilter was developed for odor emission mitigation for livestock facilities with limited area available for biofilter installation. However, a concern about the design is that airflow and moisture may be poorly distributed across the biofilter due to the effects of gravity. Relevant data are sporadic in the literature. To fill the knowledge gap, two vertical bed biofilters were constructed at a university swine facility and monitored for two months. The monitoring was taken at 27 grid points on each biofilter per field visit. Results revealed that both the airflow and medium moisture content were unevenly distributed. The sun-facing side of the biofilters had significantly lower medium moisture content (p < 0.01) due to solar-induced water evaporation. The side directly facing the barn exhaust had the highest airflow. Airflows varied along the height of the biofilters, but no significant difference was noted. The uniformity of airflow and moisture content, characterized by coefficient of variance (CV) and distribution uniformity (DU) respectively, were examined over the monitoring campaign. Possible reasons for uneven distribution were explored and recommendations are made to address the uniformity issue. The findings from the study are expected to further the development and implementation of biofiltration technology for livestock odor control. [ABSTRACT FROM AUTHOR]

• A comprehensive review of electro-driven technologies for phosphorus enrichment was provided. • Enrichment rate and energy consumption were important indicators for phosphorus enrichment. • Phosphorus enrichment promoted p recovery efficiency and vivianite formation. • Prospect and directions of electro-driven technologies for phosphorus enrichment and recovery were presented. The recovery of phosphorus from wastewater is a critical step in addressing the scarcity of phosphorus resources. Electro-driven technologies for phosphorus enrichment have gathered significant attention due to their inherent advantages, such as mild operating conditions, absence of secondary pollution, and potential integration with other technologies. This study presents a comprehensive review of recent advancements in the field of phosphorus enrichment, with a specific focus on capacitive deionization and electrodialysis technologies. It highlights the underlying principles and effectiveness of electro-driven techniques for phosphorus enrichment while systematically comparing energy consumption, enrichment rate, and concentration factor among different technologies. Furthermore, the study provides a thorough analysis of the capacity of various technologies to selectively enrich phosphorus and proposes several methods and strategies to enhance selectivity. These insights offer valuable guidance for advancing the future development of electrochemical techniques with enhanced efficiency and effectiveness in phosphorus enrichment from wastewater. [ABSTRACT FROM AUTHOR]