The massive production and use of plastic-based utensils has resulted in large amounts of microplastics (MPs) that can reach all ecosystem compartments. This is of great concern because MPs can act as vectors for organic and inorganic contaminants and thus magnify the hazardous potential of these pollutants. One of the key sources of MPs in soil systems is sewage sludge, which is widely used as an agricultural fertilizer. Besides MPs, antibiotic resistance genes (ARGs), which are associated with the overuse of antibiotics in humans and livestock, are also commonly found in sewage sludge. The presence of ARGs can drive changes in the soil microbiome and impact soil fauna and plants. Evidence of synergistic interactions between MPs and ARGs in sewage sludge and soil has also been reported. Earthworms can assist the degradation of MPs via the activity of associated enzymes and microbiota. The presence of earthworms has also been related to changes in the relative abundance of some strains of bacteria indirectly modulating their ARGs content and, subsequently, the presence of ARGs in soils. In this regard, vermicomposting has been proposed as an environmentally friendly approach to reduce the toxicity of sewage sludge before its application to soil. This chapter provides a review of the most recent literature on the interactions between MPs and ARGs and their effects on soil systems at different levels of biologic organization. Under this scenario, earthworms can act as targets of exposure to these pollutants or as a remediation tool. An overview of the relevant research conducted to date as well as a critical appraisal of the priority research topics and current knowledge gaps are addressed within this chapter.

In recent years, nanomaterials have gained special attention for removing contaminants from wastewater. Nanoparticles (NPs), such as carbon-based materials and metal oxides, exhibit exceptional adsorption capacity and antimicrobial properties for wastewater treatment. Their unique properties, including reactivity, high surface area, and tunable surface functionalities, make them highly effective adsorbents. They can remove contaminants such as organics, inorganics, pharmaceuticals, medicine, and dyes by adsorption mechanisms. In this review, the effectiveness of different types of carbon-based NPs, including carbon nanotubes (CNTs), graphene-based nanoparticles (GNPs), carbon quantum dots (CQDs), carbon nanofibers (CNFs), and carbon nanospheres (CNSs), and metal oxides, including copper oxide (CuO), zinc oxide (ZnO), iron oxide (Fe2O3), titanium oxide (TiO2), and silver oxide (Ag2O), in the removal of different contaminants from wastewater has been comprehensively evaluated. In addition, their synthesis methods, such as physical, chemical, and biological, have been described. Based on the findings, CNPs can remove 75 to 90% of pollutants within two hours, while MONPs can remove 60% to 99% of dye in 150 min, except iron oxide NPs. For future studies, the integration of NPs into existing treatment systems and the development of novel nanomaterials are recommended. Hence, the potential of NPs is promising, but challenges related to their environmental impact and their toxicity must be considered.

Second-generation biofuels from lignocellulosic biomass remain critical and require several challenges due to lignin compounds’ inefficient degradation and recalcitrate characteristics. In this regard, this study focuses on enzymatic technology as a promising treatment that is beneficial in breaking down the biomass’s hemicellulose and cellulosic parts. Thermostable bacterial species owe thermostable enzymes that are able to degrade complex carbohydrate compounds and produce efficient hydrogen production. The present study investigates the direct utilization of ligninolytic enzymes such as cellulase and xylanase derived from the hyperthermophilic bacteria Thermotoga maritima (ATCC 43589 strain). The results show that xylanase and cellulase enzymes extracted from Thermotoga maritima could depolymerize the lignin bonds of corn stover substrate and release monomers such as Galactose in the media. In conclusion, this study can open a new advanced research window on directly applying a hyperthermophilic consortium of enzymes capable of hydrolyzing lignocellulose material toward hydrogen production.

Flocculation and dewatering of anaerobically digested sludge is known to be a major cost factor in the economy of wastewater treatment plants. Hence, several endeavors have been underway in search of affordable and effective alternatives. This study focuses on the effects of different metal cations, including FeCl3, CaCl2 and MgSO4, on the dewaterability of digested sludge. The effects of these metal flocculants were also investigated in the presence of co-polymers and surfactants, which can be considered the novelty of this study. The polymers and surfactants investigated in this study were emulsion polymer, CTAB and SDS. Sampling and characterization of digested sludge was conducted, and total solid (TS), volatile solid (VS), dewaterability in capillary suction time (CST), total dissolved solids (TDS), chemical oxygen demand (COD), pH and conductivity of the unconditioned digested sludge samples were determined. The dewaterability of FeCl3, CaCl2 and MgSO4 conditioned digested sludge samples were compared, and MgSO4 conditioned digested sludge showed better dewaterability compared to the other two metal conditioning agents at a pH of 6.8. The dewaterability was further improved by the addition of emulsion polymer (EMA 8854), cetyltrimethyl ammonium bromide (CTAB) and sodium dodecyl sulfate (SDS). Fe Cl3 was found to perform better under an acidic pH of around 3. The dual conditioning using polymer and CTAB resulted in better dewaterability, with CaCl2 as metal conditioning agent. Moreover, the effects of pH, metal dose and polymer dose on the dewaterability of digested sludge were also investigated. The effects of metal and polymer conditioning on the particle size of the sludge flocs was also investigated. Optimum dewatering performance was achieved for metal doses of 0.16 v/v, 0.075 v/v and 0.16 v/v for FeCl3, CaCl2 and MgSO4, respectively, and a corresponding CTAB dose of 0.1 v/v and EMA dose of 15 kg/TDS were found to be the optimum. SDS as a polymer conditioning agent resulted in the deterioration of dewatering performance.

In recent decades rising populations and rapid urbanization have changed the lifestyles of many people. This has resulted in the generation of vast quantities of different types of solid waste. In Africa, the harsh environment (hot weather and acidic soil) and the scant awareness of organic waste recycling have led to a decline in soil quality and to uncollected waste being piled up in streets, public places, and drains. Various studies have revealed that disposal of about 90% of municipal solid waste (MSW) is uncontrolled and that waste is dumped in open areas and landfill sites, creating problems for public health and the environment. This situation has increased the need for long-term green strategies in agricultural engineering and sustainable waste management. Hence, this chapter highlights vermicomposting as a sustainable, economical approach to disposing of the waste generated in African countries and discusses the value of the technology for improving agricultural practices and soil bioremediation. Current vermicomposting scenarios practiced in Africa and their future impact are also considered. The chapter concludes with a suggestion to governmental bodies including authorities and scientists to consider ways of enhancing the practice of vermicomposting in African countries.

Green leafy vegetables are part of the Mediterranean and Middle East diets, which generate tonnes of green leafy waste. Massive production of such wastes is a challenge for policymakers, scientists, and urban local bodies to use them in a sustainable manner to convert them into valuable products. Higher education institutions such as universities are among the sectors that produce considerable quantities of organic waste daily, generated from restaurants and cafeterias. Hence, this study explores the waste treatment of university campuses using a biotechnological approach, i.e., vermicomposting technology, for sustainable management. In this study, vermicomposting was carried out using three types of green wastes [Persian-Leek (Allium ampeloprasum var. persicum), Parsley (Petroselinum crispum), and Dill (Anthemum graveolens)] obtained from restaurants and cafeterias operating on a university campus. The experiment was conducted by preparing different treatments using green vegetable wastes in different ratios with paper waste and animal manure and vermicomposted using the epigeic earthworm Eisenia fetida. The results showed that the earthworms could not survive in 100% vegetable waste due to the feed's high moisture and nutrient content. Additionally, a mixture containing 50%, 25%, and 25% vegetable waste, cow dung, and paper waste is compatible with an efficient vermicomposting process. Parsley supported earthworm survival for 45 days. Moreover, the microbial assay showed that the vermicompost contained less than 3 CFU g−1 Salmonella sp. This confirms that the obtained vermicompost is safe for agricultural use. Therefore, vermicomposting fresh vegetable waste is a viable process to achieve the aim of a green campus.

Numerous studies found the presence of persistent organic pollutants (POPs) in various environmental compartments, including air, water, and soil. POPs have been discovered in various industrial and agricultural products with severe environmental and human health consequences. According to the data, South Korea is a hotspot for POP pollution in the southern part of Asia; hence, South Korea has implemented the Stockholm Convention's National Implementation Plan (NIP) to address this worldwide issue. The purpose of this review is to assess the distribution pattern of POPs pollution in South Korea's atmosphere. According to findings, PAHs, PCBs, BFRs, and PBDEs significantly polluted the atmosphere of South Korea; however, assessing their exposure nationwide is difficult due to a shortage of data. The POPs temporal trend and meta-analysis disclosed no proof of a decrease in PAHs and BFRs residues in the atmosphere. However, POP pollution in South Korea tends to decrease compared to contamination levels in neighboring countries like Japan and China.

Microbial fuel cell (MFC) is a promising technology to generate bioelectricity from biomass feedstocks at mild operating temperature and pressure conditions. Despite promising progress in MFC systems, their commercialization has been a major challenge, mainly due to the high cost of components, limited power generation, and lower efficiency. Thus, developing economically viable and environmentally benign electrode and membrane materials that would substantially reduce the manufacturing cost and boost the performance of MFC systems is crucial. Hence, this review aims to highlight the opportunities of using abundantly available waste biomass resources to address the challenges of economic viability and low power productivity of MFC systems. In this stride, the potential of utilization of biomass waste as membrane constituents, electrode materials, and feedstock sources that would enable large-scale commercialization of MFC systems is discussed. Moreover, the study also reviews recent advances in systematic power management and optimization techniques to boost the overall power productivity and efficiency of MFC systems. Based on the comprehensive review made, it is observed that converting biomass waste resources to biochar or activated carbon for direct application as an electrode or electrode coating can decrease its cost by up to 90%. Furthermore, waste biomass-derived biochar can significantly lower the manufacturing costs of the membrane by up to 39 times. The optimum power management configurations are also proposed based on the analysis of the key factors, including the ability to boost low or ultra-low input voltage, the amount of output voltage, and the charging rate. The challenges and limitations of using waste biomass resources in MFC systems are outlined to enlighten future research directions in this domain.

This study investigated the selective production of volatile fatty acids (VFAs) during anaerobic mixed-culture fermentation. The experiment used chicken manure (CM) as a potential substrate to produce high added-value propionic acid and butyric acid under an alkaline environment. The conversion of CM into selective VFAs de-pends highly on operational conditions such as pH and redox balance. Therefore, the current experiment is designed to employ amino acid addition and develop a redox balance control method to control the final VFA profile. This study showed that 0.2-5.0 % valine and threonine addition successfully enhanced propionic acid and butyric acid production during alkaline fermentation and hence decreased the proportion of acetic acid from 83 % to approximately 47 %. The oxidation-reduction potential (ORP) and redox cofactor ratio (NADH/NAD+) were measured to support the selective VFA production mechanism. The results obtained in this study bring extra value to the valorization of CM within the circular economy concept for selective value-added VFA production.

The present study aimed to prepare biochar-derived carbocatalysts (BDCs) from three feedstocks (seaweed, microalga and lignocellulosic biomass) and further evaluate the environmental impacts through life cycle assessment (LCA) methodology. It is indicated that the step of employing chemical activation agent had the highest environmental burdens for all impact categories, followed by activation, carbonization, and transport. Amongst, the carbocatalyst from seaweed (EN-BDC) presented the highest environmental impacts for all indicators. The catalytic performance for bio-monophenols was further studied. All carbocatalysts showed the performance of promoting monophenols, especially phenol, 2-methyl-phenol and p-cresol in the bio-oil. Amongst, EN-BDC was the best for producing monophenols (total up to 54.64% of bio-oil). Furthermore, characterization of fresh and spent catalysts were carried out to investigate the difference and evolution of surface functional groups before and after reactions. The catalytic activity of carbocatalyst was mainly owing to its mesoporous structure and abundant surface oxygen-containing functional groups, especially hydroxyl groups, which was also confirmed by employing the density functional theory.

The potential of an algae-based system as an environmentally friendly and low-cost water treatment method to eliminate contaminants from water bodies has been considered. The purpose of this research was to see how effective Scenedesmus sp. is in eliminating nutrients from meat processing wastewater (MPWW) throughout the phycoremediation process. Response surface methodology (RSM) and an artificial neural network (ANN) model were applied to improve the inactivation process as a function of cell concentrations (3-7 log(10) CFU/mL) and time (1-13 days). At 10(3) to 10(7) cell/mL of Scenedesmus sp., phycoremediation was carried out at atmospheric temperature (28 +/- 2 degrees C, +/- 2500lux for 12:12 hours of light/dark and pH 8). The findings documented 73.76% as the highest removal efficacy of total nitrogen (TN) and 77.85% of total phosphorus (TP), 75.40% of ammonia nitrogen (NH4-H), 77.88% of orthophosphate (PO43-), and 64.97% of chemical oxygen demand (COD). The ANN revealed that both factors contribute significantly to the nutrient removal process. The batch kinetic coefficients of NH4-H removal were K-m = 40.10 mg/L and k = 1.43 mg mg(-1) Chl a d(-1). Meanwhile, for PO43-, 1.07 mg mg(-1) Chl a d(-1) , as well as 42.80 mg/L, were obtained. The NH4-N yield coefficient of NH4-N was Y-n = 0.0192 mg Chl a mg(-1) while PO(4)(3-)was equal to Y-p = 0.0409 mg Chl a mg(-1). These findings indicated successful use of Scenedesmus sp. for efficient pollutant removal from meat processing wastewater plants. (C) 2022 The Author(s). Published by Elsevier B.V.

The rapid growth of the world's population has led to a huge increase in food production and in turn to a huge increase in the amount of waste generated. Waste management is consequently becoming a major challenge throughout the world. Vegetable oil production has increased in recent years due to a higher demand for cooking oil. In this context, palm oil now occupies the top position in the vegetable oil market, and oil palm is one of the world's most rapidly expanding tropical crops. However, increased production of palm oil results in the generation of huge amounts of waste from palm oil mills. Therefore, waste management is a major challenge for this growing agro-industry, particularly in Malaysia and Indonesia, the major palm oil-producing countries. Palm oil mill waste (POMW) can either be vermicomposted to make biofertilizer or it can be bio-converted into biofuels, thus providing an opportunity for simultaneous waste management and establishment of a sustainable bio-economy. A number of recent studies have investigated the treatment of different types of waste generated in palm oil mills, mainly considering biodegradation processes. This chapter outlines some cost-effective and eco-friendly technologies for converting palm oil mill waste into biofuel and other value-added products. Vermicomposting is a particularly effective biotechnique for managing organic waste, in terms of viability and cost-effectiveness. Moreover, palm oil biowaste is rich in microbes and its use in producing biofuel is promising. The main goal of this chapter is to promote the utilization of palm oil mill waste under the umbrella of green, sustainable technology that can potentially boost the economies of the palm oil-producing countries.

Ammonia recovery from anaerobic digesters via side-stream stripping is a technique to recover nitrogen from manure wastes. This study demonstrated a novel approach to determining ammonia recovery to maintain total ammonia concentrations in the digester in the range of 1.7-2.1 gN/L. Increasing the pH during stripping from 8, 8.5 to 9.5 did not affect the stability of the digester. Methane yields of 60-80 mL/(gVS.d) and volatile fatty acid concentrations of 0-500 mg/L were reported throughout its operation. The low solubilisation increase upon recirculation of the digestate explained the lack of change in methane yields due to side-stream stripping. Increasing the pH during stripping also did not affect the digester's operating pH, which was attributed to the neutralising effect of biogas as stripping gas. Therefore, total ammonia concentrations in the digester can be controlled by determining the extent of ammonia recovery, and the pH during stripping can be increased without compromising the digester's stability.

Palm oil mill waste has a complex cellulosic structure, is rich in nutrients, and provides a habitat for diverse microbial communities. Current research focuses on how the microbiota and organic components interact during the degradation of this type of waste. Some recent studies have described the microbial communities present in different biodegradation processes of palm oil mill waste, identifying the dominant bacteria/fungi responsible for breaking down the cellulosic components. However, understanding the degradation process's mechanisms is vital to eliminating the need for further pretreatment of lignocellulosic compounds in the waste mixture and facilitating the commercialization of palm oil mill waste treatment technology. Thus, the present work aims to review microbial community dynamics via three biological treatment systems comprehensively: composting, vermicomposting, and dark fermentation, to understand how inspiration from nature can further enhance existing degradation processes. The information presented could be used as an umbrella to current research on biological treatment processes and specific research on the bioaugmentation of indigenous microbial consortia isolated during the biological degradation of palm oil mill waste.

Conducting polymer-based aerogels are considered as the superior composite materials for detection of volatile organic carbons (VOCs) as a result of their exceptional porosity, high surface area, and low density. The present chapter deals with the application of conducting hydrogel for the sensing behavior of VOCs. Different physico-chemical properties such as the effect of aerogel content, time, solution pH, and the effect of maximum VOC adsorption have been explored to achieve optimal aerogel. Moreover, advanced techniques of characterization such as SEM, TEM, TGA-TDA, XRD, AFM, RAMAN, and FTIR analyses have been performed to identify chemical and structural morphology of synthesized aerogel. Aerogel-based nanocomposite materials have been attracted attention because of their applications in various fields. Significant pollutants detection capacity revealed their potential in the detection of VOCs.

Phosphorus (P) is a vital nutrient for the ecosystems and its excess in wastewater streams leads to some environmental issues such as extensive algae growth (eutrophication). Phytoremediation is a green technology that is based on the combined actions of plants and their associated microbial groups to remove and transfer the toxic compounds in surface water, groundwater and soil. Aquatic plants are widely used for the remediation of contaminated rivers, eutrophic lakes, and other water bodies. In the past three decades, free-floating, submerged, emergent macrophytes and microalgae species have been used for P removal in aquatic plant-based systems such as constructed wetlands (CWs). This paper reviews the recent studies on the potential of aquatic plants such as free-floating, submerged, and emergent plants, and also microalgae for removal of P in different types of wastewaters. Several parameters such as plant species, hydraulic retention time, temperature, type of CWs, effluent concentration, and seasonal changes have effects on P removal. Based on the findings, some of the species such as Azolla and water hyacinth had the highest uptake ability up to 90% while algae species such as Chlorella showed about 70% of P removal. In addition, the mixed culture of aquatic plants can increase P removal if the interaction of the species is considered before cultivation in CWs.

Slaughterhouse and wet market wastes are pollutants that have been always neglected by society. According to the Food and Agriculture Organization of the United Nations, more than three billion and nineteen million livestock were consumed worldwide in 2018, which reflects the vast amount and the broad spectrum of the biowastes generated. Slaughterhouse biowastes are a significant volume of biohazards that poses a high risk of contamination to the environment, an outbreak of diseases, and insecure food safety. This work comprehensively reviewed existing biowaste disposal practices and revealed the limitations of technological advancements to eradicate the threat of possible harmful infectious agents from these wastes. Policies, including strict supervision and uniform minimum hygienic regulations at all raw food processing factories, should therefore be tightened to ensure the protection of the food supply. The vast quantity of biowastes also offers a zero-waste potential for a circular economy, but the incorporation of biowaste recycling, including composting, anaerobic digestion, and thermal treatment, nevertheless remains challenging.

Thermotoga maritima (Tma) contains genes encoding various hyperthermophilic enzymes with great potential for industrial applications. The gene TM1752 in Tma genome has been annotated as cellulase gene encoding protein Cel5B. In this work, the gene TM1752 was cloned and expressed in Escherichia coli, and the recombinant enzyme was purified and characterized. Interestingly, the purified enzyme exhibited specific activities of 416 and 215 U/mg on substrates galactomannan and carboxy methyl cellulose, which is the highest among thermophilic mannanases. However, the putative enzyme did not show sequence homology with any of the previously reported mannanases; therefore, the enzyme Cel5B was identified as bifunctional mannanase and cellulase and renamed as Man/Cel5B. Man/Cel5B exhibited maximum activity at 85°C and pH 5.5. This enzyme retained more than 50% activity after 5 h of incubation at 85°C, and retained up to 80% activity after incubated for 1 h at pH 5–8. The Km and Vmax of Man/Cel5B were observed to be 4.5 mg/mL galactomannan and 769 U/mg, respectively. Thin layer chromatography depicted that locust bean gum could be efficiently degraded to mannobiose, mannotriose, and mannooligosaccharides by Man/Cel5B. These characteristics suggest that Man/Cel5B has attractive applications for future food, feed, and biofuel industries.

Green information technology (IT) adoption has helped enhance the overall organization’s environmental sustainability. Developing the strategies for effective adoption of Green IT is one of the essential goals of decision-makers. This study purposes to investigate the factors that influence decision-makers’ intention to use Green IT and the proposed green IT adoption model in Malaysian manufacturing firms. The 183 valid data were obtained using survey questionnaires from Malaysia’s manufacturing industries’ industrial managers and examine collect data through two analytical techniques. Two-staged structural equation modeling and artificial neural network applied for hypotheses evaluation and finding the significance level of every factor in the model. The outcomes of hypotheses evaluation through structural equation modeling revealed that managerial interpretation and ascription of responsibility have a significant role in predicting the adoption of green information technology in manufacturing companies. Besides, the Artificial Neural Network (ANN) results showed that the managerial interpretation and ascription of responsibility are considered as the most significant factors of green information technology adoption. This study will help the decision-makers and policymakers develop policies and programs for the effective employment of green information technology in manufacturing industries.

Microalgae are photosynthetic organisms that can synthesize biomass as a potential source of bioenergy. The hydrolysis of a microalgal cell wall is the main issue in biofuel production. A cost–benefit method with a positive energy balance for cell wall hydrolysis should be optimized. Biological pretreatment is an environmentally friendly technique that has yielded promising results in microalgae because of the absence of lignin in their structure. Pretreatment with bacteria is one of the promising approaches of biological pretreatment. Generally, bacteria can produce enzymes required for the digestion of different biomasses; therefore, they do not encounter further problems associated with enzyme deactivation. Finding new bacterial isolates for biological pretreatment development is an essential step toward attaining an efficient and economic pretreatment method. In this work, the application of bacterial pretreatment in microalgal biomass is highlighted. Moreover, the potential of the microbiome from the digestive system of various organisms as a novel source of hydrolytic bacteria and enzymes is elaborated.