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International audience; Climate change and energy demand are calling for more sustainable fuels such as biomethane produced by anaerobic digestion of organic waste. Biochar addition to waste is presumed to enhance the efficiency of methane production, yet individual reports disclose contradictory results. Therefore, we performed a meta-analysis of 27 selected publications containing 156 paired measurements of control and biochar-amended treatments to assess the impact of biochar on the methanogenic performance. Results show that biochar promotes biomethane production substantially with a high Hedge's d value of 5.7 +/- 1.04, yet sporadic publications report a methane decline. Methanogenic performance is statistically controlled by feedstock type, pyrolysis temperature and biochar concentration, but not controlled by pH, size, surface area and methanogen species. These findings should help to tune the parameters of anaerobic digestion with biochar to optimize biomethane productions. Moreover, our results cast some doubt on the efficiency of adding biochar to soil to sequester carbon in soils because biochar promotes methane generation and, in turn, emissions of methane, a greenhouse gas, to the atmosphere.

Global health organizations recommend the use of cloth face coverings to slow the spread of COVID-19. Seemingly overnight, companies whose primary business is in no way related to healthcare or personal protective equipment – from mattresses manufacturers to big box stores – transitioned into the “mask business.” One of many options on the market are antimicrobial face masks, some of which contain silver and/or copper that may leach out of these masks. We exposed ten face masks to deionized water, laundry detergent, and artificial saliva to quantify the leachable silver and copper as a result of mask washing and wearing. Leaching varied widely across brand, metal, and leaching solution, but in some cases was as high as 100% of the metals contained in the as-received mask after 1 hour of exposure. This could lead to a total adult body metal exposure of up to 900 µg/kg of silver and 75 µg/kg of copper by wearing a given mask over an 8-hour workday. While this exposure could be minimized by pre-washing the cloth masks, this would seem to eliminate any (perceived) antimicrobial properties as the metals are eliminated into wastewater and/or graywater.

In this paper, the performance and effectiveness of combined sequencing batch reactor (SBR) and reverse osmosis (RO), as well as differences in treating young and matured landfill leachate, was investigated. Samples of young and stabilized leachate were collected from a municipal landfill in north-eastern Poland. The general pollution parameters, organic and inorganic indicators were determined in raw leachate and after each step of leachate treatment. The performance characteristics of the reverse osmosis system were made based on permeate flux, electroconductivity removal rate, concentration factor and removal rate. The use of biological pre-treatment had a good efficiency (>98% for both leachate) in ammonia nitrogen removal. The SBR treatment effectiveness for BOD (64%), Fe (29%), Cl− (0.2%) and Total Organic Carbon (-5.3%) was lower for young leachate compared to a stabilized. Pretreated leachate was directed to a RO system which was characterized by better operational parameters during the filtration of stabilized leachate: the average permeate flux was higher by 3.3 L/m2⋅s⋅10−6 and the filtration time was shorter by 110 min compared to the young leachate. The main reason of membrane clogging during young leachate filtration was a higher content of organic matter and its neutralization by Ca2+ and N-NH4+ presented in leachate, causing clogging of negatively charged RO membrane. Another reason could be complex formation between iron and natural organic matter that may precipitate on the membrane surface or inside the pores. This study has shown a high removal efficiency (over 80%) of the integrated SBR-RO method for all analyzed parameters.

Since invasive bladder cancer (BC) can progress to life threatening metastases, understanding the molecular mechanisms underlying BC invasion is crucial for potentially decreasing the mortality of this disease. Herein, it is discovered that autophagy‐related gene 7 (ATG7) is remarkably overexpressed in human invasive BC tissues. The knockdown of ATG7 in human BC cells dramatically inhibits cancer cell invasion, revealing that ATG7 is a key player in regulating BC invasion. Mechanistic studies indicate that MIR190A is responsible for ATG7 mRNA stability and protein overexpression by directly binding to ATG7 mRNA 3′‐UTR. Furthermore, ATG7‐mediated autophagy promotes HNRNPD (ARE/poly(U)‐binding/degradation factor 1) protein degradation, and in turn reduces HNRNPD interaction with ARHGDIB mRNA, resulting in the elevation of ARHGDIB mRNA stability, and subsequently leading to BC cell invasion. The identification of the MIR190A/ATG7 autophagic mechanism regulation of HNRNPD/ARHGDIB expression provides an important insight into understanding the nature of BC invasion and suggests that autophagy may represent a potential therapeutic strategy for the treatment of human BC patients.

Given the large number of existing wastewater treatment plants (WWTPs), this paper investigates the effects of routine operational factors on retaining the properties of the microplastics (MPs) of a typical aerobic bioreactor, which is widely adopted in both municipal and industrial WWTPs. The three most detected plastics, namely, polyethylene, polypropylene, and polyvinyl chloride, are pulverized and injected into an anoxic–oxic configured laboratory facility to explore the size distribution and removal efficiency of the MPs in the effluent. A laser particle analyzer is used for the continuous particle size distribution testing, which indicates that nearly all the particles whose diameters exceed 35 μm are retained. This phenomenon poses a threat to mammal health for particles less than 20 μm in diameter that dominate the effluent’s abundance. Comprehensive discussions and comparisons with existing works in terms of how the three operational factors affect the bioreactor’s retaining properties significantly are presented. The moderate mixed liquor suspended solids and short hydraulic retention time of the bioreactor are beneficial to the MPs removal based on the in-depth analysis of variance of the limited experiment runs. Furthermore, the sludge in the bioreactor renders an adsorption–desorption pathway in retaining the MPs.

Anaerobic fermentation is a clean production process for recycling of many agricultural and industrial wastes. During anaerobic fermentation, the existence of various inhibitors often leads to low efficiency or even failure of anaerobic digesters. 5-hydroxymethylfurfural (HMF) is such an inhibitor which can be produced in the pretreatment of biomass for subsequent anaerobic digestion. This paper provides a review of various production methods of HMF and its effects on hydrogen production, methane production and ethanol production through fermentation. The conversion and removal of HMF were summarized from the aspects of biomass pretreatment, non-biological treatment and biological treatment. This article aims to provide new ideas and methods for reducing the inhibition effect of HMF on anaerobic fermentation of biomass and restoring the performance of the anaerobic fermentation.

The scarcity and contamination of water by suspended nanoparticles and hazardous metal ions demand more performant technologies to reduce space, time and cost of wastewater treatment. For example, it is desirable to find eco-friendly chemicals that warranty simultaneous separation of colloidal particles and hazardous metallic contaminants for a more sustainable recovery of water quality. As the second part of a series of physicochemical studies about multifunctional biopolyelectrolytes (BPEs), in this paper, we present three of the main features of the glucurono ferulauted arabinoxylans (GFAXs) from nejayote: simple extraction, physicochemical characterization and multifunctional performance when used in a wastewater treatment unit. The polyelectrolytic and macrochelating properties of the GFAXs were studied through zeta potential measurements to predict and understand the multifunctional performance of GFAXs in a conventional coagulation-flocculation unitary operation. Two real cases were approached: the wastewater from silicon wafer cutting process (SWCP) and the wastewater from electroplating baths (EPB). Nejayote GFAXs showed high coagulant, flocculant and macrochelating activity in the simultaneous separation of Si4+, Al3+, Cr3+, Ni2+, Mg2+, Ca2+, Ni2+, Cd2+, Pb2+, Cu2+, Zn2+ and Fe2+. The water treatment tests demonstrate the high performance of the GFAXs in the coagulation-flocculation of the wastewater according to the following parameters: EPB wastewater at pH = 5.0 (optimal dose = 55–65 mg GFAXs/L, clarification = 380 T%/h and sedimentation kinetics = 110.4 mm/h); SWCP wastewater at pH = 5.5 (optimal dose = 30.0–32.5 mg GFAXs/L, clarification = 295 T%/h and sedimentation kinetics = 89.4 mm/h). With these results, nejayote GFAXs showed to be a sustainable solution for the wastewater treatment from semiconductor and metal finishing industry with high content of hazardous metal ions and SiO2 nanoparticles.

It is more and more urgent to develop low cost magnetic biochar for the removal of pollutants in water. In this study, magnetic biochar composites were prepared by one-step hydrothermal synthesis from sewage sludge and waterworks sludge (backwashing iron mud) and used to remove methylene blue (MB) from water. The synthesized samples were characterized by SEM, EDS, TEM, XRD, FTIR, XPS, VSM and BET. By changing the ratio of sludge and iron mud, three kinds of sludge-based magnetic biochar (SBMB) with good properties were successfully prepared. When the proportion of iron mud was higher, the samples were more magnetic, but when the proportion of sludge was higher, the adsorption capacity of the samples was greater. The magnetic materials in SBMB1, SBMB2 and SBMB3 were Fe3O4, and their saturated magnetization were 22.35 emu g−1, 45.16 emu g−1 and 53.56 emu g−1, respectively. SBMB had a good capacity for methylene blue removal and the process was rapid. In addition, SBMB had good magnetic properties, which can be easily separated from the solution by magnet after the experiment. The maximum adsorption capacities of SBMB1, SBMB2 and SBMB3 were 186.003 mg g−1, 178.786 mg g−1 and 164.316 mg g−1, respectively. In conclusion, this paper reports a simple and environmentally friendly method for the synthesis of magnetic biochar using sludge and iron mud as resources, which can provide a reasonable reference for the treatment of sewage sludge and backwashing iron mud in waterworks.

Solar steam generation-is an emerging water purification technology because it is environment-friendly and cost-effective. Continuous efforts have been made to improve its efficiency, but there are still challenges in terms of material costs, manufacturing processes, recycling, and scalable production. In this paper, inspired by the spontaneous transpiration of corn straw, the interfacial solar steam generation device was constructed under the skeleton made of cheap corn straws. Owing to outstanding hydrophilicity improved by citric acid (the water absorption rate of corn straw is 1.4 times that of natural straw), corn straw enjoys feasible water transport with vascular bundles and screens. Besides, it has excellent light absorption and photothermal conversion properties due to carbon black layer formed after sulfuric acid carbonization. The experimental results show that, based on the modified corn straws, the solar evaporator achieved an evaporation rate of 1.422 kg m−2 h−1 and corresponding solar conversion efficiency of 89.3%under 1 sun (1 kW m−2) illumination. Moreover, the evaporator performed reliable reusability and excellent desalination capacity. Therefore, using cost-effective corn straws as high efficiency solar steam generator is promising in water purification and wastewater treatment.

Effluent discharge from wastewater treatment plants (WWTPs) is an important source of microplastics, which has attracted worldwide attention. Tertiary sewage treatment of microplastics in WWTPs has also been implemented. In this paper, microplastic removal by aluminosilicate filter media and their cationic surfactant modified products as the potential low-cost integrated material was studied. The role of modified aluminosilicate filter media in the removal of microplastics from WWTPs has not been focused on in the previous studies. The concentration of microplastics with particle size 96%) and fixation capacity for PE and PA, which is much greater than that of rapid sand filter (63%). The obtained scanning electron microscopy (SEM) images showed three morphological retention mechanisms: captured, trapped and entangled. The negatively charged microplastics can also be directly electrostatically bonded with the positively charged HDPB head base. The entangled fixation mechanisms provided a higher removal efficiency of microplastics in wastewater for the modified aluminosilicate filter media than the rapid sand filter. The modified materials provided a wide range of potential for the immobilization of microplastic in wastewater treatment process. In principle, this performance can be further studied and utilized to improve the removal efficiency of microplastics in WWTPs.

Supercritical water gasification (SCWG) utilizes water as the reaction medium to convert biomass into a mixture of gases (i.e., H2, CO2, CO, CH4, and other short-chain hydrocarbons) at typical operating temperature ≥ 400 °C and pressure ≥ 23 MPa. Understanding kinetics of SCWG processes is critically important for future development and scale-up application of the SCWG technology. Thus, this study aimed to develop a general kinetic model to predict the yields of gases from SCWG of various lignocellulosic feedstocks with varying contents of cellulose, hemicellulose and lignin. The model was established based on the experimental results from K2CO3-catalyzed SCWG of various biomass model compounds including cellulose, xylan and lignin at 450–550 °C for 10–50 min, followed by validation of the model using the experimental data obtained from SCWG of real biomass (i.e., corn stalk and pinewood) under same reaction conditions. The validation results showed that the general kinetic model developed could accurately predict the yields of gases from real biomass SCWG and the quantitative influences of temperature and residence time on the gas yield in biomass SCWG. Additionally, the kinetic model has been validated other SCWG data in the literature obtained with various facilities and different lignocellulosic biomass feedstocks. The development of the general kinetic model provides an applicable way to assess the potential of SCWG of various lignocellulosic biomass feedstocks for producing combustible gases at various conditions.

Free-standing bifunctional reduced graphene oxide paper (RGOP) was facilely fabricated by evaporative self-assembly and hydrazine hydrate vapor reduction. The RGOP integrates remarkable fire resistance and outstanding electromagnetic interference (EMI) shielding performance with a total shielding effectiveness value of 41.5 dB at 0.49 mm thickness in the X band. This research provides a facile pathway to fabricate graphene macro-assembly for fire safety and EMI shielding applications.

Cellulose is a naturally occurring organic polymer extracted mainly from lignocellulosic biomass of terrestrial origin. However, the increasing production of seaweeds for growing global market demands has developed the opportunity to use it as an additional cellulose source. This review aims to prepare comprehensive information to understand seaweed cellulose and its possible applications better. This is the first review that summarizes and discusses the cellulose from all three types (green, red, and brown) of seaweeds in various aspects such as contents, extraction strategies, and cellulose-based products. The seaweed cellulose applications and future perspectives are also discussed. Several seaweed species were found to have significant cellulose content (9-34% dry weight). The review highlights that the properties of seaweed cellulose-based products were comparable to products prepared from plant-based cellulose. Overall, this work demonstrates that cellulose could be economically extracted from phycocolloids industrial waste and selected cellulose-rich seaweed species for various commercial applications.

Developing functional nanocellulose-based materials while well maintaining their inherent excellent attributes is crucial to achieve the value-added applications. However, their inherent flammability largely limits their potential applications in many fields with fire-safety concerns. In this work, an intrinsically flame-retardant nanofibrillated cellulose (NFC) was successfully prepared from kraft and unbleached bamboo pulps, respectively, via a three-step strategy involving quaternized pre-treatment, mechanical disintegration and subsequent borylation. TEM images show that the well-defibrillated cellulose nanofibrils with an average diameter of 5–9 nm were successfully obtained. The morphological, physicochemical, mechanical, thermal and flame-retardant characteristics of NFC suspensions, and their resulting films were systematically characterized. The borylated NFC film from the kraft pulp (B/Q-NFC) exhibits remarkably improved char yield while retaining high degree of fibrillation, optical transparency and mechanical properties of the Q-NFC one. Despite relatively lower optical transmittance and tensile strength, the lignin-containing NFC (L-Q-NFC) from unbleached pulp exhibits better thermal stability and outstanding UV-shielding function. Flame-retardant properties of borylated NFC samples were comprehensively investigated in terms of microscale combustion calorimetry (MCC), limiting oxygen index (LOI), vertical burning, and cone calorimetry tests. A synergistic effect was noted between B and lignin species in promoting flame resistance of Q-NFC matrix (L-B/Q-NFC). When being used as flame-retardant coatings on the filter paper and PET film, both of borylated NFC films display excellent flame-retardancy and smoke-suppression effects. In combination with of surface and bulk chemical composition analysis, TGA results as well as oxygen-permeability and thermal diffusivity measurements, the flame-retardant mechanism of borylated NFC films was elucidated. These favorite features enable them to act as sustainable fire-protective coatings for many fields such as thermal insulation, electronics, separators for lithium-ion battery, etc.

There is a dire need to cut post-harvest food loss to improve global food security, public health, and sustainable natural resource use. Fruits and vegetables constitute one of the most perishable food items and typically require cold storage systems, adequate packaging, and efficient transport and road systems to reduce their loss. This research showed that by stabilizing cornstarch and beeswax emulsion with cellulose nanocrystals, a sustainable and edible coating that substantially reduces the spoilage of fruits and other produce could be obtained. Native and aliphatic succinic anhydride-modified CNCs were employed as Pickering emulsifiers. The effect of emulsion stabilizers concentrations on the enhancement of physical properties, reduction of water vapor loss, and oxygen permeability was investigated, and 2 wt.% modified CNC was selected as the optimal Pickering emulsion stabilizer. Fresh bananas, strawberries, and fresh-cut apples that were dip-coated with the formulated edible coating displayed magnificent color and freshness preservation by reducing oxygen activities and preventing moisture losses. Overall, the studied emulsion is edible and inexpensive, making it an exciting material that can be used to combat fresh produce waste caused by oxidative and enzymatic over-ripening.

Extensive use of pesticides and their slow degradation have resulted in contamination of environment, which inflicts damages on the ecosystem and human health. The presence of pesticides in aqueous media is of a global concern. Photocatalytic processes have gained a lot of attention over the last decades with regard to degradation of pesticides. This study is aimed at reviewing the most relevant reports on the application of the photocatalytic process involved in the degradation of pesticides in aqueous solutions. Moreover, the effects of influential variables such as catalyst amount, pH, concentration of pesticides, light intensity and contact time were discussed in detail. Within this study, three subgroups of pesticides were reviewed, namely insecticides, herbicides and fungicides. Meta-analysis was also conducted by the random-effects model. In addition, statistical analyses were accomplished by the R software. After the screening process, 22 articles were found to be suitable in the meta-analysis. Results of meta-analysis proved that the photocatalytic processes could remove pesticides with an average acceptable degradation efficiency of 93.36%. The average pooled percent of photocatalytic processes for the degradation of insecticides, herbicides and fungicides was 93.35 (95% CI: 89.89–96.81), 90.73 (95% CI: 80.44–101.02) and 100 (95% CI: 98.12–101.88), respectively. The results of the Begg’s test (z = 0.4903, P = 0.6239) indicated that no bias regarding the potential publication was detected. Finally, it was demonstrated that photocatalytic processes are highly appropriate for the degradation of pesticides from aqueous solutions.

Spent coffee waste (SCW) is extremely attractive to be exploited and utilized as a material source for energy generation and chemical production. This study concerned bio-oil production via non-catalytic and catalytic fast pyrolysis using SCW in a bubbling fluidized-bed reactor (BFR). In particular, a comparative analysis of the quality of the bio-oil produced was conducted for non-catalytic (using silica sand as the bed material) and catalytic (using dolomite, HZSM-5, hematite, and magnetite as the catalyst) fast pyrolysis. Scale-up modeling confirmed using the experimental data was performed at a feed rate of 100 kg h−1 (1,000-fold capacity), which showed different orders in the quality of energy (hematite > magnetite > dolomite > HZSM-5 > silica, in order of energy from highest to lowest) owing to the realistic integration of the BFR with other components in plants, such as the combustor, compressor, and separator. Further, techno-economic analysis of scale-up system revealed that the unit production costs of bio-oil were 0.0151, 0.0034, 0.0143, 0.0095, and 0.0102 $ MJ−1 for silica, dolomite, HZSM-5, hematite, and magnetite, respectively (dolomite > hematite > magnetite > HZSM-5 > silica, in order of unit cost from lowest to highest). Among them, dolomite and hematite showed competitive unit production costs compared to the price of conventional crude oil (0.0098 $ MJ−1). The importance of coupling laboratory-scale experimental results with scale-up modeling and economic analysis has thus been demonstrated for practical feasibility studies of the SCW pyrolysis for bio-oil production.

This study represents an integrated and sustainable approach to mine fullest potential of sugarcane bagasse (SCB) for the production of bio-H2 and bioethanol along with organic farming. Experiments were designed in three phases, where feasibility of bio-H2 production was initially evaluated with pure xylose and further validated with real field feedstock (i.e, SCB). Acid pretreatment of SCB with 2% H2SO4 (v/v) yielded xylose rich hydrolysate (21.8 g xylose/100 g SCB), which was subjected to dark fermentation for bio-H2 and VFA production. Heat-pretreated inoculum at pH 7.0 showed maximum bio-H2 fraction of 34.2% (v/v) with corresponding volumetric yield of 204.5 mL H2/g xylose. 5200 mg/L of VFA was noted with butyrate and acetate as the major fermentative metabolites. The unhydrolysed biomass recovered after acid hydrolysis of SCB was further subjected to simultaneous saccharification and fermentation (SSF) for bioethanol production. SSF of cellulose rich recovered biomass with cellulase enzyme showed 86.56% (w/w) depolymerization of cellulose into glucose and production of 241.2 mg ethanol/g treated SCB by Saccharomyces cerevisiae. Lastly acidogenic effluent (AE) from bio-H2 production process was utilized as phosphate solubilizing organic fertilizer for the cultivation of chick pea (Cicer arietinum). Regular supplementation of AE showed beneficial effect on phosphate solubilization in soil and uptake by plants. The obtained results confirm the feasible utilization of segregated streams of SCB for bio-H2 and bioethanol production with integrated organic farming in a closed loop approach. This integrated strategy would extract maximum potential of the agri-biomass feedstock with net-zero waste discharge.

Primary sludge (PS) fermentation prior to anaerobic digestion (AD) is becoming more common in wastewater treatment plants (WWTPs) for the production and utilization of volatile fatty acids-rich sludge liquor in biological nutrient removal processes. However, the thermal hydrolysis process (THP) for enhancing AD of sludge in WWTPs with PS fermentation has rarely been investigated. This study examined low-temperature THP (50–90°C, 30–90 min) for enhancing co-digestion of fermented primary sludge (FPS) and thickened waste activated sludge (TWAS). The experiments were conducted under two schemes: scheme-1 (THP of TWAS + FPS) and scheme-2 (THP of TWAS only). Scheme-2 was more effective in solubilizing COD (up to 20.4% increase in SCOD) and various macromolecular compounds (e.g., proteins and carbohydrates). In contrast, scheme-1 was more efficient in VSS solubilization (up to 26.12%). Scheme-1 also resulted in a greater enhancement in methane production over the control (scheme-1: 56.28% at 90°C, 90 min vs. scheme-2: 43.4% at 90°C, 60 min). Thus, these results suggested that low-temperature THP of TWAS alone (scheme-2) would result in solubilization of refractory macromolecular compounds, leading to a relatively lower positive impact on methane yields than scheme-1. The preliminary economic assessment considering THP operating cost, enhancement in energy recovery, and saving in biosolids handling costs indicated that THP at 90°C (90 min) under scheme-1 could provide the highest net saving of $79.55/dry tonne solids compared to the control (AD without THP). These results will provide technical guidance in adopting THP in WWTPs with PS fermentation.

Monitoring of microplastics (MP) release into the aquatic environment is an important topic and proposed point sources for microplastics are wastewater treatment plants (WWTPs). Three full-scale WWTPs (A, B, C) were investigated to compare the effect of continuously and discontinuously backwashed sand filters to retain microplastics from secondary treated wastewater effluents. A cascade filtration unit using steel basket filters with mesh sizes of 100 µm, 50 µm and 10 µm was employed for sampling. The subsequent analysis used thermal extraction desorption gas chromatography mass spectrometry (TED-GC–MS). This combined analytical approach offered the benefit of sampling multiple cubic meters of WWTP effluent and using a robust quantification analytical method for microplastic without the need for an additional chemical-based sample preparation step. Due to the different capacities of the three WWTPs, the results were normalized based on population equivalents (P.E.). Four common polymers were targeted in this study (i.e., PE, PS, PP, and PET). PE was the most common polymer detected in secondary effluents, with normalized annual loads ranging between 2.8 mg yr–1P.E.-1 and 8.4 mg yr-1P.E.-1. Results showed that sand filters offered additional efficient MP retention capabilities, with the sand filters offering, on average, an extra 79% ± 11% of MP retention when compared to secondary treatment. Finally, one filter cell with aged and one with restored granular media were compared. The aged cell did not indicate lower retention of microplastic while using granular media that was already in operation for seven years.

Wastewater such as digestate from waste biomass anaerobic digestion contains a high concentration of nutrients such as nitrogen and phosphorus. A novel process for simultaneous nitrogen removal and phosphorus recovery was recently developed based on the combination of the anammox process and hydroxyapatite (HAP) crystallization. This study firstly investigated the feasibility of operating this process under low temperature using an anammox-HAP type expanded bed reactor. By gradually increasing nitrogen loading and phosphorus loading rate, a nitrogen removal rate of 8.45 ± 0.49 gN/L/d with a simultaneous phosphorus recovery rate of 0.63 ± 0.06 gP/L/d was obtained at 15 °C. The efficiency for both nitrogen removal and phosphorus recovery was higher than 80%. The addition of Ca2+ was confirmed to be an effective strategy to enhance the efficiency of phosphorus recovery by affecting the supersaturation condition of the solution. However, a high phosphorus load may result in excessively high mineral concentrations in the sludge and affect anammox performance. The granular sludge formed under low temperature conditions in this study has a typical double-layer structure of HAP-core and anammox biofilm. This study firstly demonstrated the feasibility of the anammox-HAP process even under low temperatures and give new options for future digestate treatment.

The effect of the hydraulic retention time (24, 12, and 6 h) during the co-digestion of organic residues was studied using a novel upflow hybrid anaerobic sludge reactor with a carbon/nitrogen ratio of 30, initial pH of 5.5, temperature of 35 °C, and a granular inoculum. The reactor performance at the tested HRTs followed the order 650 ± 50 (24 h) > 48 ± 4 (12 h) > 20 ± 2 mL BH2 g-1CDO removed (6 h). The content of the metabolites obtained using an HRT of 24 h followed the order acetic acid > isobutyric acid > butyric acid under acetogenic conditions. However, for HRTs of 12 and 6 h, the sequence was butyric acid > valeric acid > propionic acid > acetic acid. Based on molecular analyses, the biohydrogen selectivity was attributed to the presence of the genera Megasphaera, Clostridium, Lactobacillus, and Prevotella, which accounted for 26%, 2%, 12%, and 29% of the microbial biota at 24 h. Additionally, the yield of the upflow hybrid anaerobic reactor was superior to that of an upflow anaerobic reactor (24 h).

An ultra-low energy consumption continuous flow (UECF) process was used for enhanced nitrogen removal from rural sewage. The ammonia in sewage was first oxidized to nitrite in a bio trickling filter (BTFPN) supplemented with natural oxygen. A stable nitrite accumulation ratio (NAR) of 93.2% was maintained by adding 5 mg/L NH2OH every seven days. BTFPN effluent was then combined with certain portion of rural sewage (1:1.2 to 1:1.5) and introduced to an upflow anaerobic sludge blanket reactor, where the nitrogen-containing pollutants were removed by Anammox process (UASBAMX). Effluent total nitrogen (TN) of 6.7 mg/L and a TN removal efficiency of 93.7% were obtained when influent chemical oxygen demand (COD), NH4+-N and TN were 321.9, 74.2 and 82.7 mg/L, respectively. Advanced nitrogen removal, based on the desirable cooperation between Anammox bacteria (Ca. Brocadia, 2.3%) and partial denitrification bacteria (Thauera, 4.2%), was achieved over 300 days of stable operation. Considering the nitrogen balance, 57.9% of nitrate generated in Anammox was reduced to nitrite by partial denitrification, and Anammox contributed 88.1% of nitrogen removal and 7.6% of denitrification. Compared with conventional nitrification and denitrification processes, UECF requires no mechanical aeration, no external carbon, produces 76.6% less external sludge, and reduces CO2 emissions by 92.3%.

It is widely accepted that plastic waste is one of the most urgent environmental concerns the world is currently facing. The emergence of bio-based plastics provides an opportunity to reduce dependency on fossil fuels and transition to a more circular plastics economy. For polyethylene terephthalate (PET), one of the most prevalent plastics in packaging and textiles, two bio-based alternatives exist that are similar or superior in terms of material properties and recyclability. These are polyethylene furanoate (PEF) and polytrimethylene terephthalate (PTT). The overarching aim of this study was to examine the transition from fossil-based to renewable plastics, through the lens of PET upcycling into PEF and PTT. The process for the production of PEF and PTT from three waste feed streams was developed in the SuperPro Designer software and the economic viability assessed via a discounted cumulative cash flow (DCCF) analysis. A techno-economic analysis of the designed process revealed that the minimum selling price (MSP) of second generation-derived PEF and PTT is 3.13 USD/kg, and that utilities and the feedstock used for the production of 2,5-furandicarboxylic acid (FDCA) needed in PEF synthesis contributed the most to the process operating costs. The effect of recycling PEF and PTT through the process at three recycling rates (42%, 50% and 55%) was investigated and it was revealed that increased recycling could reduce the MSP of the 2G bio-plastics (by 48.5%) to 1.61 USD/kg. This demonstrates that the plastic biorefinery, together with increasing recycling rates, would have a beneficial effect on the economic viability of upcycled plastics.

Improvement on oxygen (O2) concentrator using pressure swing adsorption (PSA) technology according to variable product demands is of great significance, which, for instance, provides the key step for success in practical O2 therapy for COVID-19 patients who need to be delivered with a wide product flow rate range (1–15 standard liter per minute (SLPM)) of medical O2 (purity > 82%). This work studied the individual effects of major PSA process parameters on O2 production performance at the product flow rate of 3.46–19.88 SLPM (0.64–3.68 SLPM per kilogram of adsorbent (SLPM/kg)), based on a self-designed two-bed PSA unit with a modified Skarstom cycle using Li-LSX zeolite adsorbents. The improvement strategies were accordingly proposed based upon influential mechanisms of each parameter: 1) at lower product flow rates (≤2.00 SLPM/kg), increasing the purge flow rate and decreasing the adsorption pressure to suppress excess O2 adsorption, and decreasing the feed flow rate to ensure low energy consumption; 2) at higher product flow rates (≥2.00 SLPM/kg), decreasing the purge flow rate and increasing the adsorption pressure to eliminate N2 breakthrough and O2-rich product waste, and appropriately increasing the feed flow rate to enhance cost-effectiveness. An improved set of parameters rendered O2 purity (95.67–74.86%), recovery (11.28–49.05%), productivity (0.47–2.04 mmol/kg/s) increased by up to 3.52–20.08%, 0.36–20.47%, 6.82–19.61%, and energy consumption (4.07–0.95 kWh/kgO2) decreased by up to 10.56–18.10%, in comparison to two conventional sets, respectively. The results are beneficial for developing intellectualized and flexibly-controlled O2 concentrators for practical applications.

This study reports the performance of a new homogenous solar/sodium hypochlorite/iron process in treatment of petroleum refinery wastewater for the aim of water reusing. A pilot-scale solar photo-reactor with capability of automatic rotating against the sun’s surface was employed. Experiments were conducted by following the chemical oxygen demand (COD) and the total organic carbon (TOC) criteria at different times. The optimal operating conditions of 548 mg/L of sodium hypochlorite, 48 mg/L of ferrous salt and pH 3 were found under which COD and TOC removal of, respectively, 78.6% and 69.3% were corresponding after 180 min treatment. The COD removal could easily reach to 88.5% by multiple feeding of the reagents. A significant improvement in the biodegradability was also achieved by raising the BOD5/COD ratio from 0.36 to 0.69. The GC/MS headspace analysis indicated a high degradation level of the most hydrocarbons. Meanwhile, the COD removal was appeared with a pseudo first order kinetic in term of accumulated UV energy. Comparing the performance with the alternative processes including solar Fenton as well as the cost estimates revealed the high preference of the employed process.

Lime hemp concrete (LHC) is one of the most environmentally friendly alternatives to traditional building materials, which is normally used as an insulation material. The lime hemp concrete is made up of hemp shiv and aerial (or hydraulic) lime and has the ability to offer better thermal and acoustic performances. However, it is reported that the shiv/matrix reaction does not always meet the expectations, thus the properties of hemp concrete may be affected by certain characteristics, such as origin, retting time, harvest time, etc. of the used hemp. During this work, the authors have studied the influence of variability of hemp shiv on the setting of LHC. The results depicted that the soluble components (e.g., organic acids, simple sugars, etc.) from hemp shiv had a significant impact on the setting and hardening of mortars. This study also proved that hemp containing more soluble components tends to involve a longer setting time and hinders long-term carbonation reaction of binders. Furthermore, the experimental results also showed that water treatment can effectively remove these soluble agents from hemp shiv and improve the compatibility between shiv and binder in the composite.

This study investigated the comparative performances, fouling mitigation efficiencies, and operational costs of side-stream and submerged osmotic membrane bioreactors (OMBR) systems using an outer-selective hollow fiber thin-film composite forward osmosis (OSHF TFC FO) membrane. Generally, the submerged OMBR system exhibited the higher fouling mitigation efficiency and a much slower flux decline rate when compared with that of the side-stream system. The side-stream OMBR system demonstrated an initial water flux of 15.8 LMH using 35 g/L NaCl as the draw solution, which was 2-fold higher than that of the submerged system when at its optimal performance. However, salinity accumulation in the reactor of the side-stream system was at a higher rate than for the submerged OMBR system. Both OMBR systems showed comparably high pollutant removal efficiencies over the experimental period. Annual operating costs for the side-stream OMBR system has been estimated to be 38% higher (OPEX) than for the submerged system. Membrane replacement cost accounted for the majority of the OPEX, over 89%, while the energy consumption and cleaning costs only accounted for relatively small portions. Therefore, reducing the membrane replacement cost is critical to realizing the commercial viability of the submerged OMBR system.

Xylooligosaccharides (XOS) are naturally occurring high value biochemicals with potential applications in the food, pharmaceutical and fine chemical industries. They are typically produced and purified from a variety of biomass resources in expensive and inefficient multi-step batch processes, and this high cost of production is a significant barrier to their commercial adoption. A flow-type microreactor was used to intensify and increase the efficiency of enzymatic XOS production from beechwood xylan. The xylan hydrolysis performance was compared with the same reaction performed under typical batch conditions. Over 80 g XOS per 100 g xylan was obtained in less than one minute of residence time at the optimum conditions tested in continuous flow experiments. The enzymatic xylan hydrolysis performance was improved and xylan to XOS conversion was three times higher under optimised flow conditions compared to a conventional batch process.

Pervaporation (PV), as a cost-efficient concentrating process, has been studied for Zero Liquid Discharge (ZLD) of desalination. Although high water flux and excellent salt rejection have been reported for many PV membranes. The desalination performance, fouling behavior, and cleaning protocol for treating real reverse osmosis concentrate (ROC) generated from industrial plants have never been studied. Meanwhile, understanding the fouling behavior and cleaning method in the treating process is crucial for the development of suitable PV desalination membranes. In this study, we used a lab-made PV membrane to treat industrial ROC with a high chemical oxygen demand (COD) value and high salt concentrations. The results showed that conductivity and COD of the produced water were below 20 μs/cm and 70 mg/L, respectively, which fulfilled the discharge standard. However, the membrane fouling problem was not trivial. To address the fouling issue, a chemical softening method was adopted to remove the calcium salts of the ROC, and a membrane cleaning method was developed to regenerate the water flux. As a result, a long-term water flux of 31.27 kg/m2·h with a flux recovery rate of 98% were realized. This highlights the potential of PV desalination technology for ROC reclamation.

BISURE (BIological SUlfide REmoval) systems are efficient biological systems for sulfide removal and elemental sulfur recovery. However, they often suffer from disturbance caused by filamentous sludge bulking during startup, which are inoculated with activated sludge. In this study, BISURE startup by increasing the influent substrate concentration (IC-mode) and speeding up the influent flow rate (IF-mode) were investigated to understand and avoid the disturbance. The results showed that the BISURE system could be successfully started up in both the IC mode and IF mode, but both modes could trigger filamentous sludge bulking by Thiothrix (a filamentous sulfur-oxidizing bacteria, F-SOB). “CSO going first, PSO following up” was an effective approach to control the filamentous sludge bulking during startup. The procedure mechanism of oxygen effect was revealed: the growth of zoogloeal SOB (Z-SOB) with its larger surface-to-volume ratio (SVR) was first promoted to achieve a “proportion advantage” over F-SOB in the bacterial community; the external location of Z-SOB was then fixed to achieve the “location advantage” over F-SOB in the sludge floc; finally, prior uptake of DO by Z-SOB was ensured to achieve a “sequence advantage” over F-SOB in the substrate utilization. After elimination of filamentous sludge bulking, the dominant SOB in the bacterial community in IC-mode were Thiobacillus, accounting for more than 90% of the population; while dominant SOB in IF-mode were Thiobacillus and Annwoodia, which together accounted for more than 60% of bacteria. These findings are helpful in characterizing biological desulfurization and going forward, should be important in further developing BISURE systems.

International audience; In Normandy, the marine macroalgae become a large problem when the retreat of the tide leaves large quantities of stranded seaweed on coast. These stranded seaweeds can be toxic during their degradation in addition to creating odor problems. Consequently, their elimination has become a major problem and their recovery an emergency. In this work, we proposed to use the stranded seaweed in the building construction at a large scale. We investigated in particular the performance of insulated walls based on lightened earth incorporating reed and stranded Laminaria digitata seaweed at different substitution level. The compressive strength and the hygrothermal properties of the earth insulated walls specimens were carried out. Our results show that the incorporation of seaweed in lightened earth improves both its heat storage capacity and its level of insulation without compromising its compressive strength. The most efficient seaweed content for improving the thermal insulation of the material seems to be 20%. Indeed, the addition of 20% of Laminaria digitata decreased the thermal conductivity by 34% at 20 °C in comparison with standard cob. For this mixture, the specific heat capacity value is around 800 J.kg−1.K−1 at 20 °C, which are very high compared to that of the only earth-fiber specimen (400 J.kg−1.K−1). These increases in mechanical and hygrothermal performance of insulating cob material incorporating seaweed will lead to a reduction of the cob walls thickness and therefore to the development of sustainable energy efficient building materials with a low environmental impact.

Treatment of the huge amount of cellulose waste is an urgent challenge. Here, cellulose waste is used to prepare photocatalyst for molecular O2 activation by using a sulfuric acid-assisted hydrothermal method. The product can activate O2 to produce superoxide anion ( O2−), which can be subsequently used in Cr(VI) pollution remediation effectively by reducing it into Cr(III). The Cr(VI) removal efficiency can reach 90 % in 100 min. This is important to achieve sustainable utilization of O2 and solar energy. Compared with glucose, cellulose is a superior raw material for the synthesis of photocatalytic acid-HTCC. It exhibits higher reduction power due to its more negative conduction band edge. This low-cost, easy to prepare, and environment friendly acid-HTCC could have promising applications in environmental treatments. This work successfully turns waste into wealth, relieving the environmental concerns of cellulose waste, and provides a way to solve the urgent environmental pollution at present.

Supercritical water gasification (SCWG) is a promising waste treatment technology for streams from wine industry, which can eliminate its pollution and produce biofuels simultaneously. In this study, we investigated the influence of catalyst concentration and temperature for efficient SCWG so as to shift the product distribution toward more desirable compounds. Also, experiments have been demonstrated to examine the effect of the group 1A carbonates (Li2CO3, Na2CO3, K2CO3, and Cs2CO3). Wine industry wastes have been successfully gasified and the products were identified by using chromatographic methods. As going down from top to bottom in group 1A by increasing reaction temperature, the highest H2 and CH4 yields were obtained with Cs2CO3 at 600 degrees C. These results support the development of the reaction conditions by effective catalysts to contribute to the solution of the global bioenergy shortage and effective waste management of the industry., Scientific and Technological Research Council of Turkey (TUBITAK) [109M284], The financial support for this work provided by the Scientific and Technological Research Council of Turkey (TUBITAK) in the form of research project No. 109M284.

This study aimed to evaluate the effects of the high-intensity ultrasound (HIUS) on the recovery of phenolic compounds from the leaves, fruit pulp, and seed of Eugenia calycina Cambess. The impact of using different modes of application of the same ultrasound-specific energy (kJ/g) was examined. Ultrasound energy performance was assessed employing two different HIUS treatments for each part plant. The same specific energy levels of 2 and 5 kJ/g were applied, varying nominal power and processing time. The HIUS treatments of low-power and long-time (LPLT) and high-power and short-time (HPST) were performed at 100 W, and 475 W. LPLT treatment was non-thermal processing, while HPST was a thermal treatment. The HPST treatment showed more efficiency in the recovery of the phenolic compounds to specific energies. The leaves were the plant part that exhibited the highest content of phenolic compounds and antioxidant activity. The LC-MS analysis also showed ellagic acid and myricitrin as the main phenolic compounds in all botanical parts evaluated. The SEM showed a physical change in plant structure because of HIUS. However, the FTIR spectra indicated that the chemical functional groups were not affected by the acoustic energy. Despite the HPST treatment increased the medium temperature, the stability of antioxidant compounds was preserved. The interaction of the high nominal power, short processing time, and moderate temperature employed in the HPST extraction procedure positively affected the extraction yield of phenolic compounds from the Eugenia calycina.

This study investigates the effect of the specially designed adsorptive packed column system (APCS) in improving the quality of biogas to biomethane purity. The APCS installed with the specially constructed “dispersal star” was operated on biogas from wastewater treatment plant. The four adsorbent packed columns were arranged based on two impregnated and two no-impregnated commercially available active carbons to remove siloxanes, halogenated compounds and volatile organic compounds. The removal performance of ACPS was tested using portable devices along with gas chromatography techniques coupled with different types of detectors. The removal efficiency of total non-silica impurities was obtained at the level of 99.76%, whereas siloxanes were removed entirely. The adsorption affinity of siloxanes in the shape of D4 and D5 was considered by adsorption on high BET surface area adsorbent, while the desulphurisation process was conducted on impregnated active carbons. This study describes the concentrations of silica and non-silica impurities in relation to CHP manufacturers’ limits and biomethane quality. Furthermore, the economical estimation of full-scale APCS was also conducted taking into account the three variants of biogas purity, as well as different types of iron-based adsorbents.

Characterized by the high concentration suspended solids (SS), chemical oxygen demand (COD), biological oxygen demand (BOD), ammonium nitrogen and total phosphorus (TP), a solid–liquid separation as a pretreatment is mandatory for swine wastewater before biological treatment. In this study, batch tests of electrocoagulation were investigated under different structural parameters (anode material, inter-electrode distance) and operational parameters (current density, stirring speed, initial pH and reaction time). The results showed that the optimal conditions were the Fe anode, inter-electrode distance of 2.0 cm, current density of 30 mA/cm2, no stirring, initial pH of 6.3 without control and reaction time of 35 min in this study. By comparing with chemical coagulation, satisfactory performance was achieved under optimal electrocoagulation: supernatant recovery of 60%, SS, TP, COD and BOD removal efficiencies of 98.5%, 99.5%, 50.6% and 10%. In addition, fluorescent substances formation was observed under electrocoagulation and thus increased the BOD/COD ratio from 0.36 to 0.66. The enhanced biodegradability would facilitate the subsequent biological removal and the overall swine wastewater treatment. Conclusively, the iron electrocoagulation technology is a promising process for high-strength swine wastewater pretreatment.

Dark fermentation (DF) systems usually exploit bioH2 production aiming to improve the energetic potential (EP) of anaerobic digestion (AD) schemes. In the case of sulfate-rich substrates, the versatility of fermentative consortia may favor the establishment of sulfidogenic conditions, minimizing/eliminating the competition between sulfate-reducing bacteria (SRB) and methanogens in the sequential stage and providing sulfide-free biogas. This study details the establishment of sulfidogenesis on the thermophilic DF of sugarcane vinasse in a continuous polyurethane-filled fixed-film reactor, also estimating the EP for vinasses according to different AD-related approaches. High sodium levels naturally stimulated SRB by maintaining high pH values (> 6.0), whilst NaHCO3 dosing was required when natural buffering conditions were not maintained. High acetate (~ 3 g-COD L−1) and COD/sulfate ratio (> 25.0) levels indicated a high-quality substrate for further methanogenesis. High butyrate concentrations (~11 g-COD L−1) coupled to caproate detection indicated the occurrence of chain elongation processes, leading to low bioH2 production levels (

To evaluate and approve the materials that can be in contact with drinking water with respect to biological contamination, organic carbon migration and biomass formation potential assays are widely employed. In previous studies, to conduct the assays, the entire material was exposed to the test water by submerging the material into glass jars. However, these are not realistic conditions since the water contact only the inner surface of the pipe in the distribution system, which may be different from the outer surface with respect to the coating layers. Furthermore, the extra components such as the glass jar containers and stainless steel holders might be the sources of organic carbon contamination. These two factors may result in imprecise conclusions. Here, we introduced a minor but essential modification to the BioMig test, which is the most current test on the migration potential and biomass formation potential. In this modified BioMig method, the outer surface and cutting edges, which are not in contact with water in practical water distribution systems, would not be exposed to the test water. Moreover, the assimilable organic carbon formation potential via chlorination in the leachates was observed and recommended as an additional test in the migration potential assay. The modified test results demonstrated that polyethylene (PE) material is the most unfavorable material, notably when used in chlorinated drinking water. This proposed test provided an alternative approach to the decision-makers with respect to evaluating the pipe material characteristics.

Anaerobic digestion (AD) can be a viable treatment option of organic wastes from restaurants, also generating biogas and digestate. Therefore, the aim of this work is to assess the treatment of organic residues from a university restaurant of Federal University of Santa Maria (UFSM). For this purpose, a 200 L semi-pilot scale anaerobic digester was monitored over 240 days, operating at mesophilic temperature in different hydraulic retention times (30 and 60 days). Substrate and digestate pH varied from 4.8 to 6.3 and 6.2–7.3, respectively. The average removal of chemical oxygen demand, biochemical oxygen demand, total solids, sedimentable solids, and volatile solids were 95%, 95%, 53%, 93%, and 77%, respectively. Biogas yield was 0.22 m3∙kg−1 VS or 67 L kg−1 of substrate with 60% of CH4 in average. Despite the variability in substrate composition, the results show high efficiency of the AD operation on decreasing the polluting potential of food waste, simultaneously generating both biogas and digestate, as a potential organic fertilizer. This work is a pioneer in the energy use of food waste from university restaurants in RS-Brazil, providing important information on AD operation, which can be useful in the design of a larger scale plant.

In this study, the production of fermentable sugars and biogas from thermally pretreated brewer’s spent grains (BSGs) was investigated. There were two autohydrolysis conditions (C1-1S: 180 oC, 30 min, 5 mLH2O gBSG−1 and C2-1S: 180 oC, 60 min, 5 mLH2O gBSG−1) which were evaluated, with and without a previous low severity pretreatment (80 oC, 10 min, 10 mLH2O gBSG−1). The highest specific methane production (302.4 NLCH4 kgCOD−1) and enzymatic hydrolysis yield (EHY of 98%, 50 FPU gBSG−1) were obtained from the two-stage pretreatment, with the second stage operated at 180 °C for 60 min, 5 mLH2O gBSG−1. However, in the integrated process, the two-stage pretreatment with the second stage performed at 180 °C for 30 min, and 5 mLH2O gBSG−1 was the best condition to produce fermentable sugars from enzymatic hydrolysis of pretreated BSGs, using a lower enzyme loading (EHY of 93%, 25 FPU gBSG−1). The burning of biogas produced from an anaerobic digestion of liquid fractions (hydrolysates) generated after two-stage thermal pretreatment in a combined heat and power system can produce a net thermal energy of 1.71 MJ kgBSG dry basis−1 and electrical energy of 0.392 kW h kgBSG dry basis−1.

Innovative removal of toxic nitrite and ammonia is one of the key approaches for efficient aquaculture biotechnology. This study suggests a fast removal technique of high-levels of nitrite and ammonia using recirculating aquaculture wastewater at 30‰ salinity. Four lab-scale moving bed biofilm reactors (MBBRs; R1, R2, R3, and R4) were operated in parallel for 56 days with different combinations of mature and fresh biofilms on biocarriers at 30% filling ratio. Nitrogen removal efficiency, biofilm physicochemical properties, and microbial analyses were conducted using PCR and sequencing techniques at the region of the 16S ribosomal RNA. The results showed that R4 (using mature biofilms) recorded the highest nitrite and ammonia removal (99.6% and 95.3%, respectively) compared to the control, R1 (94.1% and 89.4%). Meanwhile, the removal rate of ammonia in R4 was significantly the fastest compared to other reactors. Partial Least Squares-Discriminant Multivariate Analysis (PLS-DA) model showed a good prediction with very high accuracy and prediction (Q2 > 0.8) for the first three principal components pertaining to nitrite and ammonia removal. Planktosalinus genus was the most abundant in R4, while proteobacteria phylum was the dominant, followed by Marinobacter and Nitrospina in all reactors. Overall, the use of mature biofilms in MBBR was proven to increase bacterial diversity, enhancing nitrite and ammonia removal efficiency.

In recent times to address the energy issues, the use of microalgal feedstock as third generation biofuel has gained significance due to sustainability and feasibility. Compared to terrestrial plants, it has a higher growth rate and superior CO2 and sunlight fixation capacity; along with higher lipid content. However, a major bottleneck which impedes the mass production of microalgal oil is the high cost of harvesting. Therefore, energy efficient and eco-friendly harvesting techniques are crucial to improve the economic viability of algal biofuel production. In this study, pellet forming Aspergillus sp. was evaluated for the efficient biomass recovery of Chlorella sp. MJ11/11 through the process of fungal pelletization. The effect of different process factors like: rotational speed of the shaker, pH, nutrients and cationic agent concentrations in the media on biomass recovery were evaluated. When algae: fungi were used in 1:3 w/w ratios, more than 90% harvesting efficiency was obtained at pH 3 within 5 h. Fourier transform infrared spectroscopy analysis showed changes in the C-H and C-N groups indicating their role in co-pelletization process. The CHNS characterization of the co-pellet showed an improved C/N ratio, with a high heating value of 19.55 MJ Kg−1. The lipid and biomass concentration of the co-pellet was 332 mg L−1 and 2.37 ± 0.12 g L−1 respectively. Also, the X-ray diffraction analysis indicated an increase in the amorphous property of the co-pellet; demonstrating the suitability of the algal fungal co-pellet as a substrate for biofuel production.

Microalgae have a high potential for the bioremediation of landfill leachate, mainly via nutrients removal, with the possibility of using the biomass for different purposes, depending on its characteristics. The present work aimed to evaluate the effect of hydraulic retention time (HRT) on the growth of microalgae in landfill leachate and on the composition of the biomass. Three photobioreactors (PBRs) with HRTs of 3, 6, and 10 days were used (PBRs 1, 2, and 3, respectively). Temperature, pH, ammonia nitrogen, total phosphorus, chemical oxygen demand, volatile suspended solids (VSS), and chlorophyll a (chl a) were monitored. The biochemical characterization of the biomass was carried out for lipids, carbohydrates, proteins, and ash. Chl a concentrations were 15.1 mg.L-1, 13.3 mg.L-1, and 4.9 mg.L-1 for PBRs 1, 2, and 3, respectively. For VSS, the concentrations were 130.4 mg.L-1 in PBR1, 149.1 mg.L-1 in PBR2, and 124.2 mg.L-1 in PBR3. The highest proportion of the biomass of the three reactors was protein, reaching 51.1% in PBR2. This result is justified by the high nitrogen concentration in the landfill leachate. The highest lipid accumulation occurred in PBR3, reaching 16.6%, due to the greater nutritional limitation imposed by the higher HRT. The results of this study provide important information for the use of HRT as an operational parameter for the production of algal biomass in landfill leachate, both in terms of productivity and biomass composition.

Spent brewer’s yeast is an underused by-product, whose current management offers low returns. This article studies, for the first time ever, the hydrothermal treatment of spent brewer’s yeast, paying special attention to the effect of the presence of oxygen on the physical properties, composition and potential recovery of valuable products from the hydrolysed yeast, as previous step towards the employment of these recovered proteins as renewable chemical feedstock for green industrial uses. Results showed a higher VSS disintegration employing an oxidising atmosphere, as well as a better solubilisation in terms of solid COD reduction, although it also lowered soluble COD but without significantly reducing soluble TOC. Both treatments led to an almost complete solubilisation of protein and carbohydrates from yeast, which were subsequently degraded in presence of oxygen if reaction times were lengthened. Looking at biopolymer recovery, protein precipitation by pH adjustment worked better in hydrolysates obtained in presence of oxygen, with almost 90% of protein precipitation and good selectivities at pH 2.5 and 3. Salting out was more effective, in terms of selectivity, for samples obtained in absence of oxygen and low concentrations of ammonium sulphate. The application of IMAC showed better results on yeast hydrolysates obtained under an inert atmosphere, reaching maximum sorption capacities of almost 100 mg protein/g dry resin, three times higher than those observed using the hydrolysate produced in presence of oxygen. A new perspective in yeast management during beer production is open as renewable chemical feedstock for protein, although further studies are required to optimise protein recovery and purification with respect to its applications.

Anaerobic Membrane Bioreactors (AnMBRs) combine the advantages of anaerobic processes and MBR technology to improve effluent quality and energy recovery. However, these systems are associated with operational challenges such as membrane fouling and loss of dissolved methane that increases operation and energy expenses. In this study, a new configuration was developed combining AnMBRs with Microbial Electrolysis Cells (MECs). The effectiveness of the coupled AnFMBR-MEC system was tested by monitoring several indicators during the treatment of synthetic wastewater. The new configuration exhibited a 25-day shorter startup period, a 56% enhanced average methane yield, and a reduced membrane fouling with a maximum transmembrane pressure value nearly 6.5 folds lower than that exhibited by the AnFMBR alone. AnFMBR-MEC had an average CE of 40% and both reactors achieved around 90% COD removal. Similar bacterial communities existed in both reactors but with different relative abundance and localization. In the AnFMBR-MEC, the Direct Interspecies Electron Transfer was the likely dominant route for acetate consumption due to the abundance of Geobacter and Methanosarcina on the granular activated carbon and in suspension. The new system offers a promising technology with less fouling and improved resource recovery from wastewater due to the presence of different environmental niches (GAC, anode, cathode) for microbial colonization and growth, which resulted in the reduction of biomass in suspension and the proliferation of electroactive bacteria and methanogens as biofilms.

Bioleaching is an eco-friendly alternative for the extraction of metals from the spent fluid catalytic cracking catalyst (SFCCC). Acidothiobacillus ferrooxidans (A. ferrooxidans) are the most widely reported bacteria in leaching but remained unexplored for SFCCC till date. The present study proposes a cleaner, environmentally friendly process to leach metals from SFCCC by A. ferrooxidans. Batch bioleaching of metals was carried out with unadapted and adapted A. ferrooxidans. Experiments were performed by varying the pulp density (PD) (1–20%) at two different initial Fe(II) concentrations i.e. 2 g/L [M2Fe(II)] and 8.84 g/L [M8.84Fe(II)]. The results showed that adapted A. ferrooxidans leached out metals better than unadapted ones. Even though the loss of Iron to Jarosite formation was higher in M8.84Fe(II) than in M2Fe(II), leaching remained higher in M8.84Fe(II). Jarosite formation was minimized by maintaining the pH of the medium to 2 ± 0.1. Maximum leaching efficiency was observed at 1% PD. At this concentration. A. ferrooxidans growth was triggered which increased the production of Fe(III), thereby increasing leaching efficiency. Increase in PD led to a decrease in metal leaching efficiency. The maximum leaching observed by A. ferrooxidans is Al (35%), Ti (14%), Ni (27%) and V (56.5%). The amount of Al leached (70 mg/gm of SFCCC) suggests SFCCC be the potential secondary source of Al compared to popular secondary sources such as red mud and other spent catalysts. Al and V were better leached by A. ferrooxidans while organic acids were more suitable to extract Ti and Ni from SFCCC.

The focusing phenomenon is a difficult point during the electrokinetic remediation (EKR) of contaminated soil. It restricts the extraction and removal of heavy metals. There is still a lack of methods to discern focusing position rapidly and take proper measures. Therefore, a total of seven tests with or without intervening and regulating measures were conducted. Among the four tests without regulating and intervening measures, focusing position often appeared in low-voltage region after three days’ treatment. When using ammonium citrate as electrolyte, the highest removal efficiency of total chromium (Cr) (32.20%) was achieved. The intervening measure that adding citric acid near section 4 decreased the area of high-voltage and made it move towards cathode. Meanwhile, the removal efficiency of Cr(VI) (60.17%) was significantly improved. Using sodium dodecyl sulfate (SDS) as pretreatment agent and electrolyte made the position of high-voltage area move towards anode and removed 35.80% of total Cr and 53.47% of Cr(VI) eventually. Simultaneously, the energy consumption per gram of removed Cr was also the lowest. The focusing degree was reduced with intervening and regulating measures conducted but focusing position still existed in low voltage area, which further indicated that focusing position preferred to appear in low voltage area and we could discern focusing position through voltage distribution across the soil roughly.

China's toilet modernization has enabled thousands of villages to separate their feces and urines from the greywater or washing wastewater. Human feces and urine are usually used as raw materials for fertilizers, but the lack of understanding of discharge characteristics of washing wastewater in China rural areas affects the development of treatment technology and the reuse of treated water. In this study, a village in the lower reaches of the Yangtze River was selected to investigate the discharge characteristics of washing wastewater, and four kinds of subsurface constructed wetlands were used for treatment and reuse. The results showed that the production of washing wastewater in rural aeras was 59–232 L/(cap .d), with an average of 121 L/(cap .d). The bathing wastewater contributed the highest proportion of 46.19%. COD was identified as the key pollutants with average concentration of 337 mg/L. Compared with domestic wastewater, the concentrations of TN and TP were much lower with the average of 11.1 mg/L and 0.6 mg/L respectively. After treated by the constructed wetland with ceramsite, volcanic rock and anthracite as composite substrate, the effluent water met the requirements of paddy field crop irrigation, and the removal rates of COD, TN and TP achieved 61.5%, 68.8% and 70.5% respectively. Wetland plants and modular design had significant positive effects on the removal of nitrogen and phosphorous, but little effect on COD removal. The fecal coliforms in the effluent were all lower than 4.0 lg (MPN/L) in the four constructed wetlands, indicating they were not the limiting factors for irrigation reuse.