The effects of feedstock type on hydrothermal liquefaction were explored through the co-conversion of waste activated sludge and various lignocellulosic biomass sources, including birchwood sawdust, cornstalk, and waste newspaper. This investigation aimed to produce bio-oil under consistent conditions at 310 degrees C and a 10-min reaction time, with subsequent comparison to results obtained using single feedstocks. The co-feeding of sludge with cornstalk and sawdust demonstrated the highest bio-oil yields at 34.2 % and 33.7 % wt%, respectively. The comprehensive characterization of the bio-oil products revealed that feedstock type influenced elemental composition and, consequently, the higher heating value of the bio-oils. Bio-oils derived from co-feeds exhibited a significant presence of nitrogenous compounds, esters, and fatty acids in contrast to the high percentage of phenolic compounds found in bio-oils from single feedstocks. Furthermore, these co-feed bio-oils displayed lower molecular weights, higher quantities of low boiling point compounds, increased volatile matter content, and reduced fixed carbon content compared to bio-oils produced from single feedstocks.

Hydrophilic phenol-formaldehyde (PF) foams, widely used in floral and hydroponic applications, are produced using phenol typically derived from non-renewable petroleum-based resources. This study examines the potential of depolymerized Kraft lignin (DKL) as a sustainable substitute for phenol in the synthesis of hydrophilic biobased foams. At 50 % DKL substitution, the foams demonstrated excellent water absorption capacities (up to 2557 %), relatively low densities (∼62 kg/m3), and nearly 100 % open-cell content. Its compressive strength (20.64 kPa at 10 % deformation) is comparable to commercially available floral and hydroponic foams. Additionally, foams with 10 % phenol substitution by DKL exhibited better thermal stability compared to neat phenolic foams. After 15 days of incubation with Laccase-producing bacterium Bacillus sp., 30 % and 50 % DKL foams exhibited the highest weight loss of 39.03 % and 38.9 %, respectively. Qualitative degree of biodegradation was further assessed using scanning electron microscopy and FT-IR analysis of the degraded samples.

Recovery of clean water and valuable nutrients from wastewater was investigated using a flow electrode capacitive deionization (FCDI) process operated in short-circuited closed cycle (SCC) mode. Orthophosphate was selected as a model nutrient, and its removal and recovery were studied using carbon black (CB) and activated carbon (AC) as flow electrode. A narrow-channel crossflow reactor equipped with ion exchange membranes (IEMs) and turbulence-promoting netting was used for the investigation. The flow electrode materials were characterized using Brunner-Emmett-Teller (BET), Scanning Electron Microscope coupled with Energy Dispersive X-ray (SEM/EDX), X-Ray Diffraction (XRD), and X-Ray Photoelectron Spectroscopy (XPS). The effects of applied voltage, flow rate, flow electrode loading, and initial pH and feed concentration were systematically studied. A mathematical model was developed to predict the time-dependent phosphate concentration, demonstrating a strong correlation with the experimental data. Additionally, parameter optimization using Response Surface Methodology (RSM) revealed that applied voltage and initial pH significantly influenced phosphate removal, while physisorption was negligible compared to electrosorption. Close to 92

The market for hydrophilic polyurethane (PU) and phenol-formaldehyde (PF) foams is rapidly expanding. However, conventional petroleum-based foams cause environmental concerns due to their slow to nearly absent biodegradability and reliance on non-renewable resources. Recent advances have focused on integrating biobased components such as lignocellulosic biomass, comprising of lignin, cellulose, and hemicellulose, in foam formulations to enhance sustainability and performance. This review presents a comprehensive overview of biobased PU and PF hydrophilic foams, highlighting their synthesis, properties, applications (floral, hydroponic, and environmental remediation), biodegradability, life cycle analysis and critical analysis of the economic, environmental, and technical challenges involved in developing and commercializing biobased foams for hydrophilic applications.

Efficient orthophosphate recovery from wastewater is essential for sustainable nutrient recycling. This study evaluated the effectiveness of an oscillatory electrode reactor (OER) employing sacrificial magnesium electrodes for enhanced phosphate removal, improved struvite recovery, and reduced electrode passivation. Baseline experiments in a batch electrochemical reactor (BER) identified optimal operating conditions and subsequently applied them to OER experiments by systematically varying oscillation frequency (0-8 Hz), amplitude (0-10 mm), and initial solution pH (range 4.0-10.0). Results indicated that electrode oscillation significantly improved phosphate removal efficiency, achieving approximately 86 % removal compared to 48 % without oscillations. Oscillation frequency had a greater influence on phosphate removal than amplitude, with maximum phosphate removal observed at 8 Hz, 10 mm amplitude, and at initial pH similar to 9.0. Oscillations also significantly reduced electrode passivation, maintaining stable electrode performance. A simplified model correlating phosphate removal enhancement with oscillatory shear rate was developed, achieving excellent agreement (R-2 = 1) with experimental data. The OER system demonstrates substantial potential as a chemical-free, sustainable, and efficient technology for orthophosphate recovery, supporting wastewater treatment strategies and circular economy objectives.

Phenol formaldehyde foams, extensively utilized in wide range of applications face challenges due to depleting petroleum resources and adverse environmental concerns. This study explores a promising shift to biobased alternatives, specifically investigating the use of Kraft lignin (KL) by replacing about 10 to 50% phenol content to synthesize open-cell hydrophilic phenolic foams. The produced foams undergo comprehensive testing to evaluate wetting properties, porosity, mechanical strength, and biodegradation potential. Remarkably, foams with a high percentage of Kraft lignin exhibit outstanding physical and wetting characteristics. Notably, substituting 50% of phenol with KL gave rise to a foam with a density of 40 kg/m3, 3 , open cell porosity of about 100%, water absorption capacity of 2100%, and an average water uptake rate of 0.9 cm3/s. 3 /s. Furthermore, these lignin-substituted foams display enhanced biodegradability compared with their petroleum-based counterparts. The foam with the 40% phenol substitution exhibits the highest weight loss of approximately 68% in 15 days during the biodegradation test. The biodegradation was further confirmed using scanning electron microscopy and FT-IR analysis of the degraded samples.

Open-cell phenol (P) formaldehyde (F) foams are used for various applications such as hydroponic seed germination, flower arrangements, and sound insulation. This study investigated the influence of various parameters such as F/P molar ratios, blowing agents, surfactants, wetting agents, polymeric and inorganic additives, and oxidizing agents on the hydrophilicity of PF foams. Experimental results indicate that an F/P ratio of 1.8 was ideal for producing phenolic foams with good foam structure, uniform pore distribution, and favorable mechanical properties. A mixture of pentane and hexane at a mass ratio of 1:3 (wt/wt) used as a blowing agent resulted in a foam with the lowest density. With the optimal foaming catalyst (p-toluene sulfonic acid) at a loading of 28 wt%, the foam exhibited a low density and excellent mechanical properties. A phenolic foam with a low density (39.27 kg/m(3)), high water absorption capacity (1210 wt%) and high open cell content (78.94%), was achieved by combining 6 wt% Tween-80 as the surfactant and 3 wt% sodium dodecyl sulfate as the wetting agent. Additionally, 6.5 wt% loading of H2O2 led to a slight decrease in the foam density (38.46 kg/m(3)), but with a remarkable improvement in the wetting characteristics (water absorption capacity-2404 wt% and nearly 100% open cell content of the produced foam.

The presence of heavy metal ions, particularly Cr (VI) in water, is a serious environmental concern. There is a need to develop low-cost and efficient methods for sensing and removing Cr (IV) ions selectively. In this paper, floral waste (FW) extract is used for the synthesis of Ag NPs for sensing Cr (VI) ions in an aqueous solution. Silver nanoparticles (Ag-NPs) were characterized using spectroscopic (UV–visible and FTIR), X-ray diffraction, TEM, and SEM techniques. UV–visible spectroscopic studies revealed that in the presence of Cr (VI) ions, there is an abrupt change in the λ max value of Ag NPs in aqueous solution, indicating that the synthesized Ag-NP is an excellent sensor for the spectroscopical detection of Cr (VI) ions with a low detection limit of 0.5 ppm. The method is fast, economical, simple, and efficient.

Wastewater treatment plants receive significant microplastics, which are eventually discharged into the environment. Previous studies indicated that over 90% of microplastics, especially microfibers from laundry wastewater, are retained in primary sludge. The effect of microfibers from household laundry on anaerobic digestion has yet to be fully understood, which is the objective of the present study. The results in this study showed a positive correlation between methane production and the presence of microfibers. Compared to the control, the methane production increased by 2%, 27% and 43% with 20 mg/L, 100 mg/L and 1000 mg/L microfibers spiked into primary sludge, respectively. The present study suggests that microfibers at 20 mg/L insignificantly affected methane production in controlled anaerobic digestion. In contrast, ozone pretreatment of microfibers enhanced gas production by 12% in the same concentration level. Interestingly, ozone pretreatment at a higher concentration (100 mg/L-1000 mg/L) of microfibers did not affect methane production. SEM/EDX results imply that the ozone pretreatment has changed the surface characteristics of the microfibers, which provide more surface area for adsorption. The significant reduction of soluble phosphorus by 58% indicates that microfibers potentially act as a site for adsorption during anaerobic digestion. Overall, the presence of microfibers had a positive effect on anaerobic digestion. However, this work also indicated that the microfibers were not biodegraded during anaerobic digestion. Therefore, microfibers accumulate on biosolids, potentially affecting the final disposal of microfibers.

Algal blooms can seriously affect the operation of water treatment processes including low-pressure (micro- and ultrafiltration) and high-pressure (nanofiltration and reverse osmosis) membranes mainly due to the accumulation of algae-derived organic matter (AOM). This study investigated the effect of granular activated carbon pretreatment on PVDF microfiltration performance for the removal of AOM. Dissolved organic matter (DOM) solution of commercial humic acid, extra- and intracellular organic matter from two species of algae, and Cyanobacteria were used for the investigation of the fouling potential of the membrane. A comparison study of different DOM removal and fouling behavior of MF after GAC adsorption as pretreatment was evaluated under variable GAC dosage and solution pH. Almost 15-20% improvement in flux and decline in irreversible fouling occurred due to the pretreatment using 1.0 g/L of GAC for an hour. The intracellular material caused higher membrane fouling than the commercial humic acid due to the hydrophilic nature of the AOM. Membrane fouling and decline in flux increased with increasing pH in the range of 5.0-8.0. The comparison results might help to provide insights into the real challenge to deal with the treatment of algal-laden water.

Membrane fouling potential due to particle deposition in a submerged membrane reactor (SMR) was investigated using aeration and membrane oscillations. A mathematical model describing the particle dynamics and the magnitude of the forces acting on a particle/agglomerate near a membrane surface was developed. The simulation results were verified by conducting experiments with inert glass bead sizes (2.5-33.0 mu m) at various aeration rates (1.0-4.0 LPM), oscillation intensity (frequency 0-11.34 Hz; amplitude 2-6 mm). Additionally, photocatalytic degradation of diclofenac (DCF) (initial concentration = 4 mg/L) using UV 365 nm and TiO2 photocatalyst was used to characterize the system performance. The results indicate that membrane oscillation was significantly superior as a fouling mitigation strategy due to higher shear rates (up to 10 times) than that of aeration. In the studied operating parameter range, the simulation results indicate that in case of aeration, particles below ~ 10 mu m will be deposited on the membrane. Whereas, in case of membrane oscillation, a much smaller size of 0.1 mu m below which particles will be deposited on membrane surface. This was further confirmed by the photocatalytic degradation of DCF using oscillatory membrane in a submerged photocatalytic membrane reactor (SPMR) where close to two times higher DCF degradation occurred using membrane oscillation with a negligible transmembrane pressure drop (TMP) of (0.1-3 kPA). The presented approach will be useful in predicting the membrane fouling due to deposition of polydisperse particles in submerged oscillatory membrane reactors.

Resin acids are mixtures of high molecular weight carboxylic acids found in tree resins. Due to higher hydrophobicity and low solubility, they tend to adsorb on the suspended solids in pulp and paper (P P) mill wastewater and accumulate in primary sludge through settling. Anaerobic digestion (AD) is a common practice stabilizing sludge; however, high concentration of resin acids affects the AD process. The aim of this research was mainly to determine the impact of ferrate (Fe (VI)) oxidation on selected resin acids and anaerobic digestibility of ferrate-treated primary sludge (PS) spiked with the resin acids. First, batch control oxidation of model resin acids with Fe (VI) was conducted to identify an optimum dosage, pH and contact time using a Box–Behnken design approach. Thereafter, anaerobic treatability studies of primary sludge spiked with resin acids both under control condition and optimum ferrate pretreatment were conducted. Up to 97

In this work, the effects of extraction solvents: acetone, ethanol, dichloromethane (DCM) and ethyl acetate (EA), on the yields and characteristics of bio-oil products obtained from liquefaction of rubberwood sawdust (RS) at 300 degrees C for 30 min in water, ethanol or water-ethanol mixed solvent (50/50, v/v) were comparatively studied. When pure water or ethanol was used as the reaction medium, the highest bio-oil yield was obtained by acetone (30.41 wt%) or EA (31.69 wt%), respectively. Besides, significantly higher bio-oil yields were observed in RS liquefaction in water-ethanol mixed solvent with the maximum bio-oil yield of 56.67 wt% obtained by acetone. But ethanol was always the least efficient in recovering bio-oil in all cases. Besides, the elemental analysis showed that DCM was conducive to recover the bio-oil products with lower oxygen contents and the higher HHVs, while the acetone-extracted bio-oils were worse in quality. However, the highest carbon recovery (CR) and energy recovery (ER) were obtained by acetone due to its higher bio-oil yield produced in water-ethanol mixed solvent. As suggested by GC-MS, GPC and TGA analysis, the extraction solvents and reaction mediums both greatly affected the chemical compositions of the bio-oil products. Phenols were dominant in bio-oil products, followed by hydrocarbons, ketones, esters, etc. Acetone tended to extract the bio-oil with larger carbon numbers and molecular weights, which might explain its higher bio-oil recovery yield in water or water-ethanol mixed solvent. DCM was beneficial to recover the bio-oil was more light compounds with smaller molecular weights and lower boiling point distribution. But for the liquefaction in pure ethanol, more similar chemical compositions were observed among different samples when compared to the cases in other reaction mediums.

Microplastics pollution in the aquatic system has received significant attention due to their recalcitrant nature and ecotoxicological threat. Municipal wastewater typically contains various microplastics with synthetic microfibers as a significant constituent from the laundry process. The fate of microfibers in conventional wastewater processes is not clearly understood. In this study, the effect of coagulation on microfibers obtained from a lint screen of a domestic dryer and resuspended in pure water, and also in laundry wastewater was investigated using ferric chloride and polyaluminum chloride (PACl). The removal efficiency of the microfibers resuspended in pure water varied from 86% to 96% depending on the fiber size ranges: < 90 μm, 90-125 μm, and >125 μm with the smaller size microfibers showing a lower removal efficiency. Surfactant present in detergent in laundry wastewater reduced the microfibers removal efficiency to 0-37%, however, the addition of PACl increased microfibers removal to 90%. The optimal PACl concentrations for ≥90% removal were 1.75, 2, 4, and 6 mg/L for 0.5, 2, 4, 8 mg/L detergent, respectively. Zeta potential, FTIR, and SEM analysis were applied to observe the surface changes of microfibers during coagulation indicating possible mechanisms of coagulation. The dominant mechanisms for coagulation of microfibers by FeCl3 and PACl seem to be charge neutralization and adsorption-bridging. This work provided some insights about the fate of laundry microfibers in primary treatment processes.

This chapter reviews various technologies for waste to energy conversion. The advantages and disadvantages of each technology are discussed in this chapter. The effectiveness of a specific waste-to-energy process is determined based on the thermal potential of the waste, effectiveness of the system and the type of produced energy. The two main technologies for energy recovery from waste materials are thermochemical and biological conversions. Thermochemical conversion is defined as the decomposition of organic matters as a result of heating and/or oxidation of biomass and chemical reactions. It mainly includes combustion, gasification, pyrolysis and hydrothermal liquefaction. Combustion or incineration is an old and developed technology for the degradation of organics in the presence of oxygen. It can be performed as co-firing of biomass with coal for higher conversion efficiency and less fouling and corrosion problems compared to the combustion of biomass feedstock. Pyrolysis, defined as the decomposition of biomass in the absence of oxygen, produces syngas, liquid fuels and biochar. Hydrothermal liquefaction is another thermochemical process for the conversion of biomass to liquid fuels in the presence of water as the reaction medium. It involves a series of reactions, producing bio-crude oil, water-soluble products, solid residue and non-condensable gases as the main products. Another thermochemical process is gasification which involves the conversion of biomass into gaseous products using a gasifying agent. On the other hand, the biochemical conversion methods use microorganisms and enzymes in addition to heat and other chemicals to breakdown the biomass into gaseous or liquid fuels. Examples of biochemical conversions include anaerobic digestion, mechanical biological treatment and fermentation. Anaerobic digestion is the breakdown of biodegradable materials in the absence of oxygen. This process results in the reduction of volatile solids and the production of biogas that can be used to produce electricity and heat or cleaned and used as a natural gas substitute. Mechanical biological treatment is the integration of some of the waste management facilities such as materials recovery facilities (MRFs), composting and anaerobic digestion plants to recover recyclables and compost or digest the organic fraction of the waste through biological treatment. Fermentation involves the conversion of organic materials into bioethanol using various yeasts and microorganisms. Whereas, conversion of lignocellulosic biomass into ethanol is complex and expensive and there are still some challenges that limit its commercialization, e.g., the rigorous pre-treatments needed, the high cellulase costs and structural hindrances of lignin and hemicellulose, and high capital costs of such complex processes, etc. The biorefinery is a promising approach in which biomass such as lignocellulose could be converted into multiple high-valued biochemicals and biomaterials in addition to bioethanol.

The objective of this study was to investigate the effects of combined low-pressure ultraviolet (UV)irradiation and chlorination on the formation of disinfection by-products (DBPs) from different dissolved organic matter (DOM) as DBP precursors. Commercially available humic acid (HA), extracellular organic matter (EOM) from green algae, cyanobacteria, and diatom, namely Scenedesmus quadricauda (SQ), Merismopedia sp. (Msp), and Phaedactylum tricornutum (PT), were used as the sources of DOM. The DBP formation increased with increasing total residual chlorine; EOM from PT presented the highest formation potential followed by HA, Msp, and SQ. The low dosage of 40 mJ/cm(2) UV irradiation is insignificant to change the DBP formation from HA and SQ; however, it decreased the DBP formation from bromide-containing EOM of PT and promoted the DBP formation from EOM of Msp at various total residual chlorines. The DBP formation of each DOM correlated well with total residual chlorine. The maximum DBP formation potential (DBPFP) reduction of 42.25 and 13.75% for haloacetic acid formation potential (HAAFP) and trihalomethane formation potential (THMFP) was obtained at the UV irradiation dosage of 300 mJ/cm(2) for EOM of PT. However, for the EOM derived from Msp, a maximum increase of 58.1 and 51.1% for HAAFP and THMFP was observed after UV-chlorination.

Seasonal algal blooms in surface water release a significant amount of algal organic matter (AOM), which alters the composition of dissolved organic matter (DOM). AOM affects the drinking water treatment processes and finished water quality. In this study, the relative removal efficiency of AOM and humic acid by granular activated carbon (GAC) adsorption was determined. Batch experiments were conducted to evaluate the adsorption capacity of GAC, which varied from 4.235-31.45 mg/g for AOM originated from different algae. Freundlich isotherm models fitted the adsorption equilibrium data, and the adsorption kinetics data were fitted well using a pseudo-second order kinetic model. The calculated thermodynamics parameters (∆G0, ∆H0 and ∆S0) indicated that GAC adsorption for DOM removal was endothermic and spontaneous in nature.

This chapter overviews the generation and conventional disposal of waste plastics and conversion technologies for production of high-value products (liquid fuels and carbon materials) from waste plastics along with advantages and disadvantages of each conversion method. Waste plastics are mostly disposed of in landfills, incinerated or openly burned, which results in GHG production, contamination of the environment and creation of various health, economic, and social impacts. Recycling of plastics is an economically and environmentally viable alternative to the traditional disposal methods, however, due to the recycling challenges such as labor-intensive need for sorting and the fact that a large portion of plastics have poor quality and are unable to be reused, conversion technologies are more promising. Plastics and resins can be converted into different types of high-value products such as liquid fuels through thermal and catalytic cracking, hydrocracking/treatment. They can also be converted into syngas, naphtha and gas oil using gasification and hydrogenation. Since the carbon content of the plastics is high, producing carbon materials from waste plastics is another valuable option for plastics and resins conversion. Activated carbons with high surface areas could be produced from waste plastics or other polymers (cellulose and biomass) first by carbonization to form charcoals with or without catalysts, followed by physical or chemical activation. A proper waste plastics management (recycling and conversion to liquid fuels or carbon materials) can divert the waste plastics disposed of by landfilling and incineration, hence reducing the amount of harmful chemicals and emissions going to the air, water and soil. It can also preserve the life of aquatic animals that are suffocated by ingesting waste plastics and reduce the need for extraction of virgin materials and consumption of fossil fuels for plastics production, leading to the conservation of natural resources.

The presence of pharmaceuticals and personal care products (PPCPs) in biosolids applied to farmland is of concern due to their potential accumulation in the environment and the subsequent effects on humans. Thermo alkaline hydrolysis (TAH) is a method used for greater stabilization of biosolids after anaerobic digestion. In this work, the effect of TAH on five selected PPCPs including fluoroquinolone antibiotics, ciprofloxacin (CIP), and ofloxacin (OFLX), and three commonly used antimicrobial agents, miconazole (MIC), triclosan (TCS) and triclocarban (TCC) was evaluated. At the onset, extraction and analytical methods were optimized for maximum simultaneous recovery and LC-MS quantification of the target PPCPs from both water and biosolids for improved accuracy. The compounds were detected in the range of 54 +/- 3 to 6166 +/- 532 ng/g in raw biosoilds collected from a local WWTP. Next, batch control adsorption experiments of the selected PPCPs were conducted in various sludges, which indicated about 89%-98% sorption of the PPCPs onto solid phase due to their high octanol-water coefficients. Subsequently, thermo-alkaline (pH 9.5, 75 degrees C, 45 min) hydrolysis (TAH) was conducted to determine the extent of degradation of these compounds in deionized (DI) water and biosolids due to treatment. The degradation of these compounds due to TAH ranged from 42% to 99% and 37%-41% in pure water and biosolids, respectively, potentially lowering their risk in the environment due to land application. A list of compounds for which the optimized analytical method potentially can be used for detection and quantification in environmental samples is provided in the supporting document.

This chapter reviews advances in the fractionation of lignocellulosic biomass to its three main components, cellulose, hemicelluloses and lignin, as a pre-treatment process for resource utilization of agricultural/forestry residues for biofuels and bio-based chemicals/materials. Different pre-treatment methods such as physical, chemical, physio-chemical and biological processes are discussed with their advantages/disadvantages and challenges. Physical pre-treatments are considered eco-friendly methods as they do not require chemicals, but they have high energy consumption. Chemical methods are more popular owing to their high efficiency for almost all types of biomass. Among the chemical processes, the Kraft pulping and organosolv pulping methods have been widely used for biomass delignification and fractionation to produce lignocellulosic components (cellulose, hemicellulose and lignin). Kraft pulping is the most popular chemical pulping process applied on industrial scale, operating in water under a high pH condition with alkaline reagents. In contrast, organosolv pulping operates at mild conditions in organic solvents or their aqueous solution for fractionation of lignocellulosic biomass. Recently, ionic liquids have attracted a lot of attention as an alternative to volatile and unstable organic solvents for biomass fractionation, but they are associated with high cost, difficulty in recycling and reuse; thus, further investigation is required to make the process feasible for large scale application. Compared with other pre-treatment methods, the organosolv pre-treatment has many advantages such as high efficiency, mild operating conditions, easy solvent recovery and recycling, and relatively high purity of the biomass fractionation products. However, the inevitable loss and flammability of organic solvents are the main obstacles for industrial applications of these processes. Whereas, with the development of biorefinery, where the fractionation products (i.e., cellulose and lignin) could be valorized for the production of various high-value bioproducts, e.g., sodium carboxymethyl cellulose (CMC), phenol–formaldehyde adhesives, epoxy resins, and polyurethane foams, organosolv fractionation offers immense opportunities for resource utilization of agricultural/forestry residues.