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As a low-cost technology, the catalytic wet-peroxidation (CWPO) process can be operated without lamps and at atmospheric temperature and pressure. Currently, many studies focus on developing new catalysts for CWPO to increase the catalysts’ stability and efficiency. In this study, copper-loaded activated alumina (Cu/AA) was synthesized and used for the CWPO of catechol (a representative refractory organic pollutant). Various characterization techniques were deployed to characterize the catalysts, e.g., activated alumina (AA), as well as pristine and spent 1% Cu/AA. The innovative 1% Cu/AA catalyst exhibited good thermal stability up to 1173 K with a marginal weight loss of 13%. The Cu species were well dispersed on the activated alumina framework with no significant cluster formation. Typically, copper particles with a diameter of 20.74 nm were dispersed on the AA framework. Catechol removal was observed to be 92% with 87% mineralization at optimized conditions (initial catechol concentration = 200 mg/L, catalyst dose of 1% Cu/AA = 1 g; temperature = 323 K; pH = 6; and H2O2/catechol stoichiometric ratio = 0.5). The mineralization of catechol was analyzed using mass spectroscopy with the associated mechanism being elucidated. Results of this study indicate the synthesized catalyst has phenomenal advantages in terms of simple separation and high removal efficiency of catechol, indicating the feasibility of using Cu/AA as the catalyst for the CWPO of catechol.

Rice straw (RS) has been burned in open fields in many countries, which is a growing environmental concern. Anaerobic digestion (AD) of RS is one of the sustainable alternatives to open burning of RS for converting the biomass into methane, carbon dioxide, and digestate for use as agricultural manure. The present study evaluates the RS generation, use patterns, and greenhouse gas emissions from open field burning and the AD of RS. Results indicate the AD of RS offers greater environmental benefits than that by RS open field burning. As a result of the open burning of RS in India emitted 592032.52 kg of CO

The vermifiltration (VF) technology has gained significant attention as a green alternative for remediating domestic and industrial wastewater over the last few decades. Of late, the implementation of various modifications to the orthodox VF technology, including tweaks in the design and operation of the vermifilters, has been portrayed in the available literature. However, owing to the scatteredness of the available information, the knowledge regarding the execution of the modified vermifilters is still inadequate. Hence, an effort has been made to comprehensively overview the innovative strategies and techniques adopted to improve the organic and nutrient removal potential of the VFs from wastewater. In addition, future perspectives have been recognized to design more efficient and sustainable VFs. This review explores more of such novel tactics to improve the performance of the VF technology regarding organic and nutrient removal from wastewater. PRACTITIONER POINTS: Innovative strategies and techniques implemented to VF technology were comprehensively overviewed. Design modification and advantages of each innovation were highlighted. The pollutant removal performance of every modification was emphasized. Modified vermifilters were better than the conventional vermifilters in terms of organic and nutrient removal from the wastewater.

The Feng-Sang River is a metropolitan river in Kaohsiung City, Taiwan. In this study, Feng-Sang River sediments were analyzed to investigate the distributions and sources of polycyclic aromatic hydrocarbons (PAHs). The Sediment Quality Guidelines (SQGs), potentially carcinogenic PAHs (TEQ

Anaerobic digestion (AD) under psychrophilic temperature has only recently garnered deserved attention. In major parts of Europe, USA, Canada and Australia, climatic conditions are more suited for psychrophilic (20 ℃) rather than mesophilic (35 - 37 ℃) and thermophilic (55 - 60 ℃) AD. Low temperature has adverse effects on important cellular processes which may render the cell biology inactive. Moreover, cold climate can also alter the physical and chemical properties of wastewater, thereby reducing the availability of substrate to microbes. Hence, the use of low temperature acclimated microbial biomass could overcome thermodynamic constraints and carry out flexible structural and conformational changes to proteins, membrane lipid composition, expression of cold-adapted enzymes through genotypic and phenotypic variations. Reduction in organic loading rate is beneficial to methane production under low temperatures. Moreover, modification in the design of existing reactors and the use of hybrid reactors have already demonstrated improved methane generation in the lab-scale. This review also discusses some novel strategies such as direct interspecies electron transfer (DIET), co-digestion of substrate, bioaugmentation, and bioelectrochemical system assisted AD which present promising prospects. While DIET can facilitate syntrophic electron exchange in diverse microbes, the addition of organic-rich co-substrate can help in maintaining suitable C/N ratio in the anaerobic digester which subsequently can enhance methane generation. Bioaugmentation with psychrophilic strains could reduce start-up time and ensure daily stable performance for wastewater treatment facilities at low temperatures. In addition to the technical discussion, the economic assessment and future outlook on psychrophilic AD are also highlighted.

This chapter gives a brief introduction, key drivers, current status and future perspectives of resource and energy recovery and reuse. The chapter is divided into four sections, including the background, the current status for waste generation and recovery, the research needs of resource and energy recovery and reuse, and a brief review on the core ideas and key researches for each book chapter.

Forward osmosis (FO) considered as a promising separation process for nutrient enrichment in wastewater, is attracting increasing interest in integration with chemical precipitation and other technologies for recovering nutrients in wastewater treatment. In the chapter, the processes of nutrients recovery via FO-based systems are introduced in terms of mechanisms and influencing factors. Additionally, the key challenges related to the recovery systems discussed and some approaches are proposed to resolve these challenges. Future roadmap for future research and development on the nutrients recovery using FO-based systems are identified. Compared to aerobic FO-based systems, anaerobic FO-based processes need more investigations of their integrations’ efficiency in the context of nutrient recovery from wastewater. Emphasis is given to carry out more economic assessment and pilot- and plant-scale evolutions of the recovery systems, which makes the nutrients recovery via FO-based technologies more sustainable in wastewater treatment.

Volatile fatty acids (VFAs) are the building blocks of the chemical industry, and they are the primary contributors to the planet's organic carbon cycle. VFA production from fossil fuels (mostly petroleum) is unsustainable, pollutes the environment, and generates greenhouse gases. As a result of these issues, there is a pressing need to develop alternate sources for the long-term generation of VFAs via anaerobic digestion. The accessible feedstocks for its sustainable production, as well as the influencing parameters, are discussed in this review. The use of VFAs as a raw material to make a variety of consumer products is reviewed in order to find a solution. It also bridges the gap between traditional and advanced VFA production and utilization methods from a variety of solid and liquid waste sources for economical stability.

In this research a new process of harvesting the oleaginous yeast biomass (Yarrowia lipolytica) by flocculation followed by cell wall disruption and lipid extraction with petroleum diesel as a solvent was developed. Alum and calcium chloride along with the extracellular polymeric substance (EPS) as a flocculant were evaluated for lipid bearing biomass settling. The maximum flocculation activity of biomass using calcium chloride (36 mM) in combination with EPS (5.85 mg EPS/g biomass) or Alum (1.2 mM) with EPS (18 mg EPS/g biomass) was 74.3 and 79% and the settling velocity was 2.93 and 1.46 mm/s, respectively. To have a similar efficiency of biomass settling, 3.07 times less dosage of EPS was required in combination with calcium chloride than required with Alum. Further, settled biomass (166 g/L) was treated with N-lauroyl sarcosine (N-LS) to disrupt the cellular structure and release lipid. The released lipid was separated from cell debris and water using petroleum diesel (co-solvent) and maximum lipid recovery efficiency of 94.7 ± 1.2 % (w/w) was observed.

The effect of dissolved oxygen concentration on lipid accumulation in Trichosporon oleaginosus has been investigated. The experiment was performed in 15 L fermenters. The dissolved oxygen concentration varied by adjusting the agitation and aeration. High dissolved oxygen level at 50%–60% enhanced cell growth. Maintaining low dissolved oxygen concentration at 20%–30% during lipogenesis phase led to high final lipid content (51%) in Trichosporon oleaginosus. The consumptions of energy and cost of the process were evaluated. The energy consumption in the dissolved oxygen level optimized process was 41% less than that with dissolved oxygen level at 50%–60%. In addition, the cost was also reduced around one time in the dissolved oxygen level optimized process compared to the one with dissolved oxygen level at 50%–60%. The study provided a feasible way of enhancing lipid accumulation in Trichosporon oleaginosus and reducing the consumption of energy and cost of lipid production from Trichosporon oleaginosus.

The subject of emerging contaminants has attracted wide attention from researchers and society world over due to their emerging as well as potential adverse impacts on the environment. Many attempts have been made to shed light on the importance of the release of these contaminants into various environments and further urge policymakers to take required measures. Nevertheless, the effective long-term strategy for addressing this issue is latent in the modification of current technologies of wastewater/water treatment plants and integrating them into a holistic and circular water management system. The research on the new technologies of water treatment must be realigned to consider the real conditions and meet certain requirements set according to technical and environmental perspectives.

Fluoroquinolones (FQs), the group of broad spectrum antimicrobials, are frequently detected in different environmental compartments, mostly due to incomplete metabolism in the target organism, inefficient wastewater treatment, and disposal of expired FQs directly into the environment. Another group of the contaminants, widely present in water, air, and soils, are the metal ions (Me). In general, FQs can form stable complexes with metal ions and their co-existence with Me in the environment leads to metal complexation. The most stable complexes are formed between FQs and trivalent ions, whereas FQs and alkali-earth metal ions, i.e. Ca2+ and Mg2+, are the least stable composites. This interaction between FQs and metal ions may alter antibiotic properties. Antibacterial activity of metal complexes is generally comparable with the parent compound; however, some FQs-metal complexes are found to exhibit higher antibacterial activity. Moreover, it was proved that FQs-Me complex can display antifungal potency toward Candida albicans. The mobility of FQs in soil and/or water strongly depends on pH, temperature, and type of metal ions, present in the environment. This review provides a brief description of FQs, their properties, and capacity to form complexes with metal ions. It summarizes influence of FQs-Me complexes on microorganisms and their mobility in different media. Further, the review provides a linkage between the presence of these metal ions in the environment and their effect on the chemistry and biology of fluoroquinolone antibiotics.