Slaughterhouses generate a huge amount of highly polluted wastewater; if left untreated, this effluent could seriously threaten the environment and human health. In the present study, Ag₂O/Ba/TiO₂ nanocomposite was synthesized using the precipitation method, and its efficacy was investigated for the remediation of real slaughterhouse wastewater (SWW) under visible light. Its performance was assessed for the inactivation of bacterial strains identified in SWW and for the degradation of total organic solids, volatile solids, fixed solids, and heavy metals. The results indicated an excellent photocatalytic performance of the synthesized Ag₂O/Ba/TiO₂ nanocomposites, confirmed by 87.3% volatile solids, 30% total organic solids, and 40% fixed solids removal from SWW. The zone of inhibition runs from 4 to 9 mm, and the nanocomposites have demonstrated outstanding bacterial inactivation activity in this range. It has been shown that the synthetic Ag₂O/Ba/TiO₂ nanocomposites can function as an effective photocatalyst for the remediation of SWW and other waste products produced by various industries worldwide.

The current paper investigated the potential of oleaginous fungus Rhizopus oryzae B97 for lipid accumulation under varying process variables. The fungal strain was isolated from bread mold and analyzed for its potential to grow on sludge with simultaneous production of microbial lipids. The sludge sample was sourced from the wastewater treatment plant located in Sector I-9, Islamabad. The effects of various process variables, such as pH, temperature, carbon and nitrogen sources, and shaking, on lipid accumulation, cell dry weight (CDW), chemical oxygen demand (COD), and volatile solids (VS) removal were investigated. It was found that glucose and yeast promoted the maximum lipid accumulation. At the same time, the fungal biomass reached its maximum value of up to 64% at 30 °C and at pH 4 (CDW: 28 g/L). These process conditions also improved the sludge treatment efficiency, achieving 68% COD and 55% VS removal in 168 h. FTIR analysis of the accumulated lipids indicated strong characteristic peaks of functional groups associated with fatty acids. The GC-MS analysis confirmed the production of essential FAMEs required in biodiesel production from the corresponding fatty acids, such as oleic acid, palmitic acid, stearic acid, and erucic acid. Operation in a continuous-shaking aerobic batch reactor (CSABR) system under optimum conditions further improved the process efficiency. Overall, the results indicated the competent potential of oleaginous fungus Rhizopus oryzae B97 for lipid-based biofuel production through fatty acid transesterification.

Introduction: Soil salinization constrains maize productivity by elevating osmotic stress, disturbing nutrient homeostasis, and intensifying oxidative injury. In this study, we developed a green nano-biochar approach by synthesizing zinc oxide nanoparticles (ZnO NPs) from Coriandrum sativum leaf extract and combining them with walnut shell biochar (BC) to form a composite soil amendment, which may increase the nutrients (N, P, K) and increase plant antioxidant defenses in saline soil. Material and methods: ZnO NPs were verified as crystalline ZnO with wurtzite structure and nanoscale morphology using Scanning Electron Microscopy – Energy Dispersive X-ray Spectroscopy (SEM-EDS), Fourier Transform Infrared (FTIR), and X-ray Diffraction (XRD). A factorial pot experiment (15 days) was conducted in moderately (S-1; 4–5 dS m ^-1 ) and highly saline (S-2; 9–10 dS m ^-1 ) soils to compare ZnO NPs, BC, and composite against the unamended control. Results and discussion: Additionally, maize plants treated with the composite demonstrated improved morphological traits, including a 43% increase in shoot, 41% higher total chlorophyll content, and a 28% increase in antioxidant enzyme activity. Stress diagnostics further showed improved membrane stability, with lower reactive oxygen species (ROS) burdens and reduced peroxidation and EC under saline conditions. Across both salinity levels, the composite consistently outperformed single amendments, underscoring the value of integrating ionic buffering with micronutrient delivery. By coupling plant extract synthesis and valorization of walnut residues, this study offers a resource-efficient alternative to conventional salinity management and offers a promising approach for potential crop productivity and soil health in saline-affected agricultural lands. However, studies should be done on the large scale in experimental fields.

Introduction: Industrial wastewater (WW) has emerged as one of the significant environmental problems posing serious concerns to aquatic and human health. Among various industries, pharmaceutical compounds have been detected in various aquatic environments and food supply chains; therefore, they need an economical and efficient treatment process. Photocatalysis is a promising technology for addressing environmental pollution, such as wastewater treatment and microbial disinfection. Methods: In this study, a novel visible light-active photocatalyst was developed using activated carbon (AC) derived from local biomass; apricot kernel shell (AKS) and modified with Ag₂O/ZnO, The synthesized phototcatalyst (AC/Ag₂O/ZnO) was characterized by using various tools such as XRD, UV-Visible spectroscopy and FTIR. Extensive experiments were performed to test AC/Ag₂O/ZnO for its multi-application potential, such as degradation of selected organic pollutants, treatment of pharmaceutical WW and heavy metal removal, and microbial disinfection. In the first set of experiments, the reactive black azo dye was used as the selected model pollutant and optimized for various operating conditions such as time, pH, pollutant concentration, and catalyst dose. In the second phase, pharmaceutical WW was treated using a photocatalysis process compared to photolysis (without catalyst). The third experimental setup, AC/Ag₂O/ZnO was evaluated for its disinfection potential against common pathogens, including Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Results and Discussion: The results demonstrated up to 99% removal of reactive black azo dye within 4 h under optimum operation conditions, i.e., pH of 5.0, pollutant concentration of 10 ppm, and a catalyst dosage of 0.5 g/L. In the case of pharmaceutical WW, a significant reduction in chemical oxygen demand (COD) from 1195 to 199 mg/L was achieved, outperforming photolytic treatment, which reduced 1283.5 mg/L to 956 mg/L. The antimicrobial activity test showed efficient bacterial inhibition, with the zone of inhibition (ZOI) measuring 7 mm for E. coli, 12 mm for S. aureus, and 7 mm for P. aeruginosa. Overall, this research highlights the potential of activated carbon-based photocatalysts in addressing critical environmental challenges through efficient pollutant removal and antimicrobial action, contributing to sustainable WW treatment solutions. The findings will be very advantageous in developing an efficient wastewater treatment process, evaluating its upscaling potential, and serving as a framework for field application.

Introduction: The high proportion of sludge generation worldwide has sparked interest in utilizing it for alternative purposes. Among different potential applications, using sludge as a substrate for oleaginous bacteria is a relatively novel approach. The study was conducted to harness Streptomyces sp. to produce bio-lipids and their further processing for biofuel through transesterification.Methods: Sewage sludge was obtained from the I-9 treatment plant, Islamabad; after initial characterization the unprocessed sludge was optimized viz.: incubation time (24–96 h), inoculation rate (5–15%), pH levels (4–9), temperature (25–40°C), agitation (0–250 RPM), nitrogen sources (yeast, urea, ammonium chloride, and ammonium nitrate), and carbon sources (glucose, sucrose, starch, and dextrose). The qualitative analysis of the stored bio-lipids was performed using Fourier-transform infrared spectroscopy (FTIR) and Gas Chromatography Mass Spectrometry (GC–MS).Results and discussion: The maximum reactor performance was achieved with 40% lipid accumulation (gravimetric basis) in the dry cell biomass of Streptomyces sp. The results indicated the presence of C-H (Alkane), with additional phenolic and alcoholic bonds through FTIR, whereas the GC–MS results indicated the presence of palmitic acid and oleic acid as the most recurring compounds. This highlights the strong potential of Streptomyces sp. for biolipid based fuel production using sludge as a substrate. The contents of the extract (i.e., bio-lipids) were successfully transesterified to produce biofuels from the stored lipids. The findings indicated that the use of Streptomyces sp. potentially provides a dual benefit of reducing organic loading from the sludge along with biofuel production under optimized reactor conditions.