The increasing importance of biomass-based energy production as a critical component of sustainable energy resources and effective waste management necessitates a comprehensive understanding of the fundamental properties of biomass feedstocks. This review critically evaluates the physicochemical and fuel characteristics of seven widely available biomass sources in India (sugarcane bagasse, sugarcane tops, rice husk, rice straw, maize stalks, maize cobs, and empty palm oil fruit bunches), with a particular focus on the impact of torrefaction. Despite the well-documented benefits of torrefaction in improving biomass properties, limited studies have compared the specific effects of this thermal pretreatment process across diverse biomass sources. This review addresses this gap by critically analyzing the impact of torrefaction on key biomass properties, including hemicellulose, cellulose, lignin, elemental composition (carbon, hydrogen, nitrogen, and sulphur), moisture content, volatile matter, and high heating value, providing a comparative analysis to determine the optimal biomass for energy applications. Moreover, the review critically analyzes the impact of torrefaction on key biomass properties, including hemicellulose, cellulose, lignin, elemental composition (carbon, hydrogen, nitrogen, and sulphur), moisture content, volatile matter, and high heating value. Furthermore, the review synthesizes recent findings to identify optimum torrefaction conditions that enhances the properties of each corresponding biomass. By providing a comprehensive analysis of the complex relationships between biomass characteristics and their practical applications, this review contributes to the advancement of sustainable energy production by optimising biomass-based energy systems and promoting waste-to-energy strategies

This study explores the potential of polyculture microalgae for removing emerging contaminants – paracetamol (PCT) and caffeine (CAF) – along with organics and nutrients from greywater, while assessing their impact on microalgal growth and overall treatment efficiency. Several reactors containing varying concentrations of PCT and CAF (3 – 10 mg L?1) were monitored for total organic carbon (TOC), nitrate, phosphate removal, and microalgal growth. Polyculture microalgae achieved maximum PCT and CAF removal efficiencies of 94.3% and 43.3%, respectively, with the highest increase in microalgal dry weight (0.41 g L?1) in the run with high PCT and low CAF concentration. The polyculture microalgae achieved higher PCT removal efficiency (94.3%) compared to previous studies using monocultures, demonstrating the potential of polycultures for greywater treatment. The highest TOC (73.6%), nitrate (65.6%), and phosphate (41.4%) removal were observed in the run with the absence of contaminants. The addition of PCT and CAF led to a decrease in the removal efficiencies of TOC by 0.6 – 21.9%, nitrate by 8.7 – 63.0%, and phosphate by 18.5 – 33.1%, suggesting that these contaminants impacted the regular nutrient consumption of the microalgae. However, organic consumption increased as PCT and CAF were also used as carbon sources. Despite reduced nutrient consumption, microalgal growth increased by 24.2%.

The study addressed the need for sustainable greywater treatment, aiming to mitigate water scarcity and pollution. The potential of using microalgae cultivated in greywater with zinc oxide nanoparticles (ZnO/GAC-nanocomposite) was investigated for these purposes. A batch photobioreactor was employed for 15 d. The nanocomposite system significantly improved nutrient removal, with optimal removal efficiency of 80 % for TOC, 94.2 % for PO43?, and 99.6 % for NH4+. The presence of nanocomposites improved microalgae growth, achieving a density of 1.8 g/L compared to 0.83 g/L without nanocomposites. The microalgal biomass obtained had a high volatile matter content of 74.4 %, low ash content of 5.1 %, and fixed carbon of 20.4 %. The biomass includes 46.74 % carbon, 5.72 % hydrogen, and 38.75 % oxygen, with a high heating value of 18.32 MJ/kg. The reusability of ZnO/GAC-nanocomposite was also assessed, which maintained effective nutrient removal after four cycles, with NH4+, PO43?, and TOC removal rates of 86.1 %, 83.2 %, and 69.8 %, respectively. Comparison of treated greywater with a pH of 8.5, turbidity <4 NTU, COD, NH4+, PO43? of 34, 0.032, and 0.48 mg/L, respectively, with various reuse standards, indicated its potential reuse for toilet flushing. © 2024 Elsevier Ltd