A typical two-day start-up of municipal solid waste incinerators (MSWIs) can yield polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) and polychlorinated biphenyl (PCB) emission quantities around 10 times higher than those from an entire year of normal operations, as measured in this study. Thus, we tested specific control strategies for inhibiting the formation of chlorinated persistent organic pollutants (Cl-POPs), namely, extensively cleaning the ash accumulated beneath the furnace bed of the combustion chamber and deposited on the walls of the superheater and economizer and shortening the residence time of the flue gas in the optimal temperature window for Cl-POP formation. Also, we advanced the injection times of the activated carbon and lime slurry to lower Cl-POP emissions during start-up. Our findings show that these strategies were highly effective and reduced the Cl-POP emissions by > 98%, most of which (96.4–98.2%) was attributable to inhibiting formation. In summary, the proposed control strategies require no modifications to existing air pollution control devices, have little influence on operational cost, and are effective and feasible for the majority of MSWIs.

The comprehensive sources of particulate matter (PM) require air purification materials to possess both high filtration efficiencies and low air resistances in an effort to provide healthcare. However, the assembly of multiple-layered filters with different functions leads to high pressure drop and high operating cost. Therefore, a multifunctional air filter that can provide excellent air filtration capacity and healthcare is highly desired. Here, a novel bifunctional polyacrylonitrile/attapulgite hierarchical-structured filter with low air resistance and high adsorption capacity was designed and fabricated by embedding attapulgite nanorods during a facile electrospinning process. The hierarchical polyacrylonitrile/attapulgite membranes showed only a ∼64 Pa resistance for 0.1 μm PM. Another benefit of using the attapulgite nanorods is an adsorption effect for hazardous heavy metal ions that accompany airborne ultrafine PMs. Thereby this hierarchical membrane simultaneously exhibits an enhanced filtration performance and hazardous protection ability. Furthermore, due to the electret effect of the attapulgite nanorods, the surface potential of the membrane remains at above 2.2 kV after 600 min of continuous use, which could improve the air filtration efficiency and ensure the long-term service life of the filters. This work may provide a new approach for the design and development of multifunctional air filters for simultaneously capturing ultrafine PMs and any other accompanying hazardous chemicals.

Soil washing using a strong chelating agent is a common practice for restoring contaminated soils, but significant soil fertility degradation and high operation costs are the major disadvantages. Washing soil with a dissolved organic matter (DOM) solution has been identified as a method that can moderate the loss of nutrients in the soil and enhance metal removal. The DOM solutions were extracted from waste sludge obtained from a local whisky distillery. Single chelating washing and chelate-DOM washing were carried out using ethylenediaminetetraacetic acid (EDTA), citric acid, and DOM solutions to remediate highly Cu-contaminated soil. Two-phase washing using 0.34 M citric acid and then 1500 mg L−1 DOM solution (pH 8.5) was found to be most favorable for the soil. With this treatment, 91% Cu was removed from the topsoil; the organic matter, cation exchange capacity, plant-available nitrogen, and available phosphate content increased by 28.1%, 103%, 17.7%, and 422%, respectively.

Biodigested coffee processing wastewater (CPW) presents a high organic load and does not meet the limits imposed by legislation (namely in Brazil) for discharge into water bodies. Anaerobic digestion generally cannot provide a satisfactory organic matter reduction in CPW as a significant fraction of recalcitrant compounds still persists in the treated effluent. So, this study aims to find alternative ways to remove refractory organic compounds from this wastewater in order to improve the biodegradability and reduce the toxicity, which will allow its recirculation back into the anaerobic digester. Three treatment approaches (Fenton’s oxidation - Approach 1, Coagulation/flocculation (C/F) - Approach 2, and the combination of C/F with Fenton’s process - Approach 3) were selected to be applied to the biodigested CPW in order to achieve that objective.The application of the Fenton process under the optimal operating conditions (initial pH = 5.0; T = 55 °C, [Fe³⁺] = 1.8 g L⁻¹ and [H₂O₂] = 9.0 g L⁻¹) increased the biodegradability (the BOD₅:COD ratio raised from 0.34 ± 0.02 in biodigested CPW to 0.44 ± 0.01 after treatment) and eliminated the toxicity (0.0% of Vibrio fischeri inhibition) along with moderate removals of organic matter (51.3%, 55.7% and 39.7% for total organic carbon – TOC, chemical oxygen demand – COD and biochemical oxygen demand - BOD₅, respectively). The implementation of a coagulation/flocculation process upstream from Fenton’s oxidation, under the best operating conditions (pH 10–11 and [Fe³⁺] = 250 mg L⁻¹), also allowed to slightly increase the biodegradability (from 0.34 to 0.47) and reduce the toxicity, whereas providing a higher removal of organic matter (TOC = 76.2%, COD = 76.5 and BOD₅ = 66.3% for both processes together). Approach 1 and Approach 3 showed to be the best ones, implying similar operating costs (∼74 R$ m⁻³/∼17 € m⁻³) and constitute an attractive option for managing biodigested CPW.

Animal manure is often anaerobically digested for the purpose of producing biogas. The digested manure, namely digestate, can be applied onto farmlands to enhance crop yields as it is abundant in nutrients. However, intensive livestock farming brings about manure exceeding the carrying capacity of lands nearby. Technologies focused on nutrient recovery from digestate have been studied recently, while many problems and challenges still remain unsolved. In this article, these recovery technologies are reviewed and compared, and challenges are deliberated. Ammonia stripping and struvite formation are easily operated technologies in comparison with membrane technologies. Amongst membrane technologies, electrodialysis reversal and forward osmosis are promising due to their high resistance to membrane fouling. Further studies should be focused on the operational cost, disposal of solid and liquid residuals and marketization of the recovered products.

The presence of antibiotics in animal manure represents a significant concern with respect to the introduction of antibiotic residues to the environment and the development of antibiotic-resistant pathogens. In this review, we have (1) compiled reported detections of antibiotics in poultry litter, swine manure, and cattle manure; and (2) discussed the treatment of antibiotics during conventional agricultural waste management practices. The most reported antibiotics in animal manure were fluoroquinolones, sulfonamides, and tetracyclines, all of which the World Health Organization has listed as critically important for human health. Relatively high treatment efficiencies were observed for antibiotics in composting, anaerobic digestion, and aerobic/anaerobic lagooning. Interestingly, active management of compost piles did not demonstrate a significant increase in antibiotic degradation; however, low- and high-intensity compost systems exhibited high treatment efficiencies for most antibiotics. Anaerobic digestion was not effective for some key antibiotics, including lincosamides and select sulfonamides and fluoroquinolones. Given the potential for energy recovery during anaerobic digestion of agricultural waste, efforts to optimize antibiotic degradation represent an important area for future research. Lagoons also exhibited fairly high levels of antibiotic treatment, especially for aerobic systems; however, the operational costs/complexity of these systems inhibit utilization at the full-scale. No overall trends in antibiotic treatment efficiency during these three agricultural waste management practices were observed. Finally, we posit that increased efforts to include analysis of antibiotic residues in animal manure in national surveillance programs will provide important information to address concerns over the continued use of antimicrobials in animal feeding operations.

Recent technology developments have turned present-day unmanned systems into realistic alternatives to traditional marine animal survey methods. Benefits include longer survey durations, improved mission safety, mission repeatability, and reduced operational costs. We review the present status of unmanned vehicles suitable for marine animal monitoring conducted in relation to industrial offshore activities, highlighting which systems are suitable for three main monitoring types: population, mitigation, and focal animal monitoring. We describe the technical requirements for each of these monitoring types and discuss the operational aspects. The selection of a specific sensor/platform combination depends critically on the target species and its behaviour. The technical specifications of unmanned platforms and sensors also need to be selected based on the surrounding conditions of a particular offshore project, such as the area of interest, the survey requirements and operational constraints.

The need for sustainable production of renewable biofuel has been a global concern in the recent times. Overcoming the tailbacks of the first- and second-generation biofuels, third-generation biofuel using microalgae as feedstock has emerged as a plausible alternative. It has an added advantage of preventing any greenhouse gas (GHG) emissions with simultaneous carbon dioxide sequestration. Dewatering of microalgal culture is one of the many concerns regarding industrial-scale biofuel production. The small size of microalgae and dilute nature of its growth cultures creates huge operational cost during biomass separation, limiting economic feasibility of algae-based fuels. Considering the recovery efficiency, operation economics, technological feasibility and cost-effectiveness, bio-flocculation is a promising method of harvesting. Moreover, advantage of bio-flocculation over other conventional methods is that it does not incur the addition of any external chemical flocculants. This article reviews the current status of bio-flocculation technique for harvesting microalgae at industrial scale. The various microbial strains that can be prospective bioflocculants have been reviewed along with its application and advantages over chemical flocculants. Also, this article proposes that the primary focus of an appropriate harvesting technique should depend on the final utilization of the harvested biomass. This review article attempts to bring forth the beneficial aspects of microbial aided microalgal harvesting with a special attention on genetically modified self-flocculation microalgae.

The issues of food safety and environmental protection are attracting more and more attention. Everyday, a large number of cold chain products are delivered from suppliers to customers. The cold chain products require refrigeration equipment in delivery and should be delivered to customers as soon as possible. Therefore, the challenge of reducing carbon emission and improving the customer satisfaction should be solved. This study presents the impact of carbon emission, customer satisfaction, construction cost, and operation cost on the location of cold chain logistics distribution center. A multi-objective location model for cold chain logistics distribution center considering carbon emission is established. The carbon emission equivalent cost model considers the dynamic carbon emission during transportation and the static carbon emission of the distribution center. The penalty cost under the time window is introduced into the penalty cost model of customer satisfaction, which represents a multi-objective mixed-integer linear programming problem. A non-dominated sorting genetic algorithm II (NSGA-II) is used to design the program through double-layer composite coding. NSGA-II uses a fast non-dominated sorting approach to reduce the computational complexity of non-dominated sorting. This algorithm uses the elitist control strategy, which does not need to share parameters and is more efficient in the multi-objective optimization process. The numerical results show that the proposed algorithm can generate appropriate Pareto solutions for all objectives.

Effective pesticide remediation technology demands amendments in the advanced oxidation process for its continuous treatment and catalyst recovery. The evidence of 2,4-dichlorophenoxyacetic acid (2,4-D), an herbicide in water bodies, poses a major environmental threat to both humans and aquatic organisms. In the present study, a recirculation type photocatalytic reactor was developed to treat 2,4-dichlorophenoxyacetic acid using chitosan-TiO₂ beads prepared via impregnation method under UV light. At optimized conditions, chitosan-TiO₂ beads showed a maximum photocatalytic degradation of 86% than commercial TiO₂ (65%) and followed pseudo first-order reaction. The 2,4-D degradation follows pseudo first-order kinetics under UV irradiation with a rate constant of 0.12 h⁻¹, and the intermediates were identified using LCMS analysis. The total operational cost of the chitosan-TiO₂ catalyst was found to be profitable (Rs. 1323 for 2 L) than that of TiO₂ (Rs. 1679) at optimized conditions. The beads were reusable up to 4 consecutive cycles without loss in efficiency. This study briefs photocatalytic removal of 2,4-dichlorophenoxyacetic acid in a recirculation-type reactor for its reliability, low cost, efficiency, reusability, and commercialization.