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Anaerobic treatment of industrial wastewater using upflow anaerobic reactors is an extended trend due to its high efficiency and biogas production potential, but its implementation in some sectors is limited due to the complexity and toxicity of the wastewaters. In this study, a two‐stage expanded granular sludge bed (EGSB) reactors system has been investigated at both bench and pilot scale for the treatment of complex and toxic real wastewater from a petrochemical industry. The effect of different operational parameters including organic loading rate (OLR), hydraulic retention time (HRT) and influent characteristics over COD removal and biogas production and composition have been studied. Additionally, biomass specific methanogenic activity (SMA) and wastewater toxicity have been evaluated after long‐term operation. Optimum total HRT of 24 h has been determined resulting in total COD and SO42− removal of 56.30 ± 5.25% and 31.68 ± 14.71%, respectively, at pilot scale, and average biogas production of 93.47 ± 34.92 NL/day with 67.01 ± 10.23 %CH4 content and 5210.11 ± 6802.27 ppmv of H2S. SMA and toxicity tests have confirmed inhibitory and toxic effects of wastewater over anaerobic biomass with average maximum inhibition of 65.34% in the unacclimated anaerobic inoculum while chronic toxicity produced a decrease of an order of magnitude in SMA after 600 days of operation. This study demonstrates the feasibility of applying an anaerobic treatment to this wastewater using EGSB reactors between a 0.97–1.74 gCOD/L/day OLR range. Nonetheless, periodic reinoculation would be necessary for long‐term operation due to chronic toxicity of the wastewater exerted on the anaerobic biomass. Practitioner points: A two‐stage EGSB reactors system has been operated at bench and pilot scale to treat complex and toxic petrochemical wastewater.Optimal total HRT of 24 h resulted in average COD removal ranging from 40% to 60%.SMA and toxicity tests have been performed to study long‐term acclimation, detecting an activity depletion of an order of magnitude. [ABSTRACT FROM AUTHOR]

This study investigated the effect of anaerobic treatment on the non-volatile components and angiotensin-converting enzyme (ACE) inhibitory activity in purple-colored leaf tea. Results showed that after 8 h of anaerobic treatment, the γ-aminobutyric acid (GABA) content significantly increased from 0.02 mg/g to 1.72 mg/g (p

BACKGROUND: This study aimed to investigate the effect of 6, 12, and 24 h short‐term anaerobic treatment on kiwiberry quality and antioxidant properties at 5 °C. RESULTS: Short‐term anaerobic treatment was found to delay ripening and softening in kiwiberries, evident from changes in ethylene release, total soluble solids, starch, protopectin, and fruit texture. The 24 h treatment group exhibited the lowest decay rate of 12% on day 49, a 38% reduction compared with the control group. Anaerobic treatment reduced flesh translucency and decay in the fruit. The 12 h and 24 h treatments enhanced the activities of superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase, and increased the level of total phenolics, flavonoids, anthocyanins, and ascorbic acid. Moreover, it lowered oxidative damage in cell membranes, evidenced by reduced malondialdehyde content and relative conductivity. CONCLUSION: These results indicate that anaerobic treatment maintains the fruit quality by stimulating its antioxidant defense system. Therefore, short‐term anaerobic treatment emerges as a promising method for kiwiberry storage. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The search for cleaner and more sustainable energy sources is increasingly growing. Aligning this demand with another environmental problem, such as sewage treatment/disposal, is a strategic priority. In light of this, the aim of this study was to estimate the energy potential of sewage generated in the Brazilian state of São Paulo (SP) by using it to produce biomethane. The study also evaluated the viability of using this byproduct of sewage treatment (biomethane) as a substitute for natural gas (NG), as both of them have similar lower heat values. To do this, information was gathered regarding the population, gross domestic product per capita, sewage collected, and natural gas consumption for each of the state's 645 cities, and, based on this, the sewage energy potential, the amount of NG to be substituted by biomethane, and the reduction in CO2 emissions were calculated. Moreover, in order to address a possible allocation of biomethane that could potentially be produced in each SP city and sent to currently NG-consuming cities, an optimization algorithm was proposed. The results indicated a sewage energy potential of 4.68 × 109 kWh/yr for the entire SP state, which would be enough to supply around 10% of the energy value of all the NG currently consumed. It was also observed that from 130 cities with NG consumption, 10 could produce enough biomethane to fully satisfy the natural gas demand. In the elected scenario of optimization, 291 cities were found to be capable of supplying the demand of 26 cities that currently use NG. The potential to reduce CO2 emissions is between 1.81 × 106 and 2.42 × 106 ton/yr, and this range could increase if sewage treatment coverage grows. Despite the challenges inherent in extrapolating a potential study to scenarios that require significative investment, the results obtained are useful for formulating public policies for decarbonization in the near future. [ABSTRACT FROM AUTHOR]

Hydrothermal carbonization (HTC) has developed considerably over the last 15 years and offers a viable alternative for the utilization of municipal and industrial organic waste such as sewage sludge. However, the technology has yet to establish itself as a valorization process for waste biomasses (2024) and is not yet a recognized state of the art. Nevertheless, the HTC technology could gain greater relevance in the future, especially as an alternative valorization pathway for sewage sludge. During HTC, significant amounts of HTC process water (PW) are produced as a byproduct. The process water is inorganically and organically polluted and has to be treated, as it would be a burden on water bodies and thus on the environment if left untreated. In the EU and specifically Germany, industrial wastewater producers like HTC-plant operators are obliged to treat their industrial wastewater before discharging it into the environment. In addition to a large amount of PW and its treatment to the required limits, the organic load and possible persistent and toxic substances pose major challenges for plant operators. Many proven processes from industrial wastewater treatment were transferred for the treatment of PW. Treatment of the PW in a manner that is industrially viable, economically viable, and efficient is crucial for the effective commercialization of HTC technology. In this, the challenges and opportunities of PW composition, management, and treatment, including legal aspects, are mainly discussed. Therefore, the legal framework in the European Union and specifically for Germany will be elaborated. Furthermore, different treatment pathways are also highlighted. [ABSTRACT FROM AUTHOR]

Slaughterhouse wastewater is characterized by high concentrations of organic matter. This creates a need to explore methods for its treatment before discharge. This study evaluated the efficiency of an integrated treatment process consisting of a laboratory-scale upflow anaerobic sludge blanket reactor and a pilot-scale horizontal subsurface flow wetland. This treatment was used for (i) the removal of organic matter through anaerobic–aerobic microbiological processes, (ii) the conversion of organic matter from hydraulic processes, and (iii) for bioremediation and phytoremediation. The treatment system was evaluated at hydraulic retention times (HRTs) of 7.5, 5.0, and 2.5 d; during the investigation, the influence of the HRTs on the removal efficiency of the system was evaluated. High efficiencies of 85% and 75% were obtained for CODT and BOD, respectively, at an HRT of 7.5 d. The highest overall efficiency for the removal of total solids was observed at an HRT of 2.5 d. The results obtained confirm the feasibility of implementing the suggested system as an alternative for the adequate and sustainable treatment of slaughterhouse wastewater, and the system can be applied to slaughterhouses with similar conditions to those in this study. [ABSTRACT FROM AUTHOR]

Food waste has emerged as a pressing concern, and thus advanced techniques to valorize food waste into nutrition rich materials as well as renewable energy are highly important. The exceptional biodegradability of food waste renders it a highly suitable substrate for anaerobic treatment. This leads to energy production and a reduction in the carbon footprint. Nevertheless, in frigid territories like Canada, the conventional mesophilic anaerobic digestion at 30–40 °C can require substantial amounts of energy. Consequently, this study introduces a new approach to treat food waste at psychrophilic temperatures (1–20 °C). Lower temperatures can negatively impact cellular processes during anaerobic treatment, rendering substrates less accessible to microscopic organisms. To address this challenge associated with lower temperatures, the study introduces an innovative biogas recirculation strategy. The primary objectives of this study are to assess the viability of anaerobic treatment for food waste at psychrophilic temperatures and to investigate the effectiveness of reintroduction of the produced biogas to the anaerobic system in enhancing biomethane generation and stability of the system. Batch experiments were conducted on food waste in various assessments, both with and without biogas recirculation. The outcomes revealed a methane concentration ranging from 68% to 93% when biogas recirculation was employed, whereas without this technique, methane concentration varied between 10% and 45%. Moreover, with biogas recirculation, the reduction in volatile solids reached a maximum of 92%, and there was an 82% decrease in chemical oxygen demand. In conclusion, the utilization of the recirculation of biogas at the psychrophilic temperature range enhanced biomethane production and reduction of volatile solids and chemical oxygen demand. This study underscores the potential of employing anaerobic treatment with reintroduction of produced biogas into the system in cold regions as an economically viable and sustainable choice for treating food waste with nominal energy consumption. [ABSTRACT FROM AUTHOR]

The anaerobic treatment of sulfide-containing organic wastewater (SCOW) is significantly affected by pH, causing dramatic decrease of treatment efficiency when pH deviates from its appropriate range. Fe0 has proved as an effective strategy on mitigating the impact of pH. However, systematic analysis of the influence mechanism is still lacking. To fill this gap, the impact of different initial pH values on anaerobic treatment efficiency of SCOW with Fe0 addition, the change of fermentation type and methanogens, and intra-extracellular electron transfer were explored in this study. The results showed that Fe0 addition enhanced the efficacy of anaerobic treatment of SCOW at adjusted initial pH values, especially at pH 6. Mechanism analysis showed that respiratory chain-related enzymes and electron shuttle secretion and resistance reduction were stimulated by soluble iron ions generated by Fe0 at pH 6, which accelerated intra-extracellular electron transfer of microorganisms, and ultimately alleviated the impact of acidic pH on the system. While at pH 8, Fe0 addition increased the acetogenic bacteria abundance, as well as optimized the fermentation type and improved the F420 coenzyme activity, resulting in the enhancement of treatment efficiency in the anaerobic system and remission of the effect of alkaline pH on the system. At the neutral pH, Fe0 addition had both advantages as stimulating the secretion of respiratory chain and electron transfer-related enzymes at pH 6 and optimizing the fermentation type pH 8, and thus enhanced the treatment efficacy. This study provides important insights and scientific basis for the application of new SCOW treatment technologies. [ABSTRACT FROM AUTHOR]

The present work deals with the anaerobic treatment of molasses-bearing pharmaceutical wastewater using a specifically designed downflow anaerobic bioreactor (DFAB). The capacity of the designed DFAB was 1,000 L of adequate volume with necessary operational controls. Two types of anaerobic treatment, i.e. mesophilic and thermophilic treatments, were applied to the anaerobic biotransformation of wastewater under investigation. The efficiency of both treatments was compared in terms of reducing biochemical oxygen demand (BOD) and chemical oxygen demand (COD) load, as well as methane production. The anaerobic digestion process was carried out with the help of bacterial strains. The bacterial strains used in the mesophilic operation were acclimatised and utilised for the thermophilic treatment, which is a cost-effective and sustainable approach. A significant reduction in BOD and COD content of the wastewater was noticed after 10 days of retention time. Nearly 72–83% and 80–90% reduction in BOD values were recorded under mesophilic and thermophilic operations, respectively. Approximately 73–86% and 82–93% of COD content were reduced by mesophilic and thermophilic treatment, correspondingly. Methane production of 67 and 74% was achieved under mesophilic and thermophilic treatment, respectively. The designed DFAB showed remarkable treatment efficiency for wastewater and methane production. HIGHLIGHTS Anaerobic treatment of molasses-containing pharmaceutical wastewater in downflow anaerobic bioreactor.; The bacterial consortium used for mesophilic treatment was acclimatised for thermophilic treatment.; Mesophilic treatment resulted in an average of 75 and 78% reduction in BOD and COD, respectively.; On average, 86% BOD and 88% COD were removed in thermophilic conditions.;

Food waste has emerged as a pressing concern, and thus advanced techniques to valorize food waste into nutrition rich materials as well as renewable energy are highly important. The exceptional biodegradability of food waste renders it a highly suitable substrate for anaerobic treatment. This leads to energy production and a reduction in the carbon footprint. Nevertheless, in frigid territories like Canada, the conventional mesophilic anaerobic digestion at 30–40 °C can require substantial amounts of energy. Consequently, this study introduces a new approach to treat food waste at psychrophilic temperatures (1–20 °C). Lower temperatures can negatively impact cellular processes during anaerobic treatment, rendering substrates less accessible to microscopic organisms. To address this challenge associated with lower temperatures, the study introduces an innovative biogas recirculation strategy. The primary objectives of this study are to assess the viability of anaerobic treatment for food waste at psychrophilic temperatures and to investigate the effectiveness of reintroduction of the produced biogas to the anaerobic system in enhancing biomethane generation and stability of the system. Batch experiments were conducted on food waste in various assessments, both with and without biogas recirculation. The outcomes revealed a methane concentration ranging from 68% to 93% when biogas recirculation was employed, whereas without this technique, methane concentration varied between 10% and 45%. Moreover, with biogas recirculation, the reduction in volatile solids reached a maximum of 92%, and there was an 82% decrease in chemical oxygen demand. In conclusion, the utilization of the recirculation of biogas at the psychrophilic temperature range enhanced biomethane production and reduction of volatile solids and chemical oxygen demand. This study underscores the potential of employing anaerobic treatment with reintroduction of produced biogas into the system in cold regions as an economically viable and sustainable choice for treating food waste with nominal energy consumption.

Life cycle assessment (LCA) has been a well-known tool to evaluate the potential environmental impacts associated with products or processes from the cradle to the grave. The scientific community in LCA and wastewater treatment (WWT) has widely used the LCA approach to evaluate different WWT scenarios since the 1990s. Anaerobic technology to treat municipal wastewater has drawn more attention recently since it has significant potential to elevate energy saving and reduce operating costs. This review presents studies published since 2000 and aims to investigate how life cycle thinking tools are applied to assess the environmental sustainability in studies using different anaerobic WWT configurations (e.g., comparison of the other anaerobic systems with conventional systems, comparison of various anaerobic systems used with hybrid aerobic systems, or comparison of the same processes with different operation conditions) in municipal wastewater. This study consists of a step-by-step analysis of the LCA methodology. Climate change (CC), acidification potential (AP), and eutrophication potential (EP) are the most assessed environmental impacts in the LCA studies dealing with anaerobic WWT technologies. According to the studies, anaerobic WWT of municipal wastewater tends to have a less environmental impact than conventional activated sludge systems related to nutrient and energy recovery and dissolved methane capture from effluent. This study also highlights the factors affecting LCA results, like functional unit (FU) and system boundary selection, data collection, impact categories, and impact assessment methods selection. Moreover, challenges and future directions for LCA applications in anaerobic treatment technologies are discussed. [Display omitted] [ABSTRACT FROM AUTHOR]

The costs associated with microalgal biomass production can be reduced by leveraging alternative and cheap growth media. Digestate from fermentation reactors is a particularly interesting candidate for use in cultivating mixotrophic species. The aim of the present study was to assess whether pre-digested milk-industry effluent can be harnessed to grow Tetraselmis subcordiformis and produce hydrogen. The experimental series with 25% and 50% effluent in the growth medium performed the best, producing more than 2000 mgVS biomass/dm3. The biogas produced in these variants contained over 60% hydrogen. Increasing the effluent in the medium to 75% led to significant deterioration of performance, both in terms of T. subcordiformis biomass growth and biohydrogen production. The highest efficiency of nitrogen and phosphorus removal, respectively 98.1 ± 1.9% and 97.1 ± 1.4%, was observed in the system to which 25% of sewage was introduced. Increasing the share of fermented wastewater directly reduced the efficiency of removing biogenic compounds. A very strong negative correlation was found between initial N-NH4 in the growth medium and T. subcordiformis biomass production rates (R2 = 0.9177). [ABSTRACT FROM AUTHOR]

Fruit juice industry wastewater is characterized by high chemical oxygen demand (COD) and low pH, which requires extensive energy if treated aerobically and can adversely affect aquatic organisms if discharged into water bodies without proper treatment. In this study, purple non-sulfur bacteria (PNSB) were employed to recover carbon through photoanaerobic treatment in the form of single-cell protein (SCP) suitable for aquaculture and rich in carotenoid and bacteriochlorophyll photopigments. The efficacy of PNSB was investigated using two types of wastewaters, citrus juice wastewater (CJW), and mixed juice wastewater (MJW) as substrates at different pH conditions (5.0–8.0). pH 8.0 showed the highest COD removal in CJW (89 ± 0.1%) and pH 7.0 in MJW (94 ± 1%), respectively. The biomass yields were 0.493 g-VSS·g-COD−1 and 0.397 g-VSS·g-COD−1 for CJW and MJW. SCP contents in CJW and MJW were 48 ± 1% and 40 ± 3%, respectively. Pigment analysis revealed that PNSB biomass contained carotenoids and bacteriochlorophyll. Carotenoids in CJW and MJW were 1354 ± 64 µg·g−1 and 1558 ± 218 µg·g−1 of biomass; bacteriochlorophyll contents were 2097 ± 110 µg·g−1 and 3100 ± 614 µg·g−1 of biomass, respectively. The microbial population showed diversity among the two substrates and pH conditions, with PNSB comprising potentially up to 51% of microbes in the culture. The results demonstrate that PNSB could be used as potential mediators to treat fruit juice wastewater, and produce SCP, and photopigments simultaneously. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Interdisciplinary studies on cultural heritage artworks provide efficient solutions to control fungal growth and the negative effects of biodeterioration. In this study, we aimed to identify the population of filamentous fungi colonizing an engraving by the Dutch painter Rembrandt, whose conservation status was compromised and showed visible stains of biodeterioration. Microbiological techniques, such as cultivation‐dependent approaches and molecular biology, have been used to identify fungal populations. In addition, the anaerobic atmosphere technique and eco‐friendly antifungal agents, such as essential oils (EOs) of Curcuma longa, Thymus vulgaris, and Melaleuca alternifolia, were tested against the metabolically active fungal population Cladoposporium spinulosum. Furthermore, in vitro assays revealed that the interaction between the fungal strains and EO was positive, inhibiting the growth of these fungi, and the EOs from T. vulgaris and M. alternifolia showed low minimum inhibitory concentration values. Exposure to anaerobic conditions for 35 days was effective in the total elimination of isolated fungal strains. In conclusion, this study demonstrated the effectiveness of a nondestructive technique for artwork on engraving colonized by fungal strains and using EO as an alternative to toxic antifungals used in conventional treatments in artworks. Thus, this interdisciplinary study involving applied microbiology and botanical and preventive conservation presents a tool to control microbial growth while maintaining artwork integrity. [ABSTRACT FROM AUTHOR]

Copyright of Industrial Water Treatment is the property of CNOOC Tianjin Chemical Research & Design Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Light saturation of photo-fermentation is an important parameter that impacts fermentation efficiency, especially in mass culture. In other words, unsteady light irradiation negatively affects biohydrogen production. In this study, it is hypothesized that hydrogen-producing bacteria exposure to laser irradiation will improve the survival competence of bacteria to unstable illumination, overcome the challenge of light saturation, and increase biohydrogen production. The experimental design can be summarized as follows: exposing the bacterial inoculum to helium–neon (He–Ne) red or green laser for 2 h, and subsequently blending the inoculum with food wastes in addition to water through the ratio 0.5:1:2 and adding the mixture to photobioreactors irradiated with white light-emitting diodes (LEDs) with a luminous flux of 3600 lm and at 30 °C for 26 days with mixing for 5 min every 30 min to produce biohydrogen. The results indicated that an improvement in the bioresponses of bacterial cells which increased the biohydrogen yield by 1.79 and 1.2 times the control (un-irradiated inoculum) when using He–Ne green and red laser irradiation, respectively. The green laser activation for bacterial inoculum showed the maximum H2 yield of 25.4 mol H2 mol/mol sugar. However, the inoculum with red laser irradiation delivered 15.2 mol H2 mol/mol sugar. The least H2 yield of 12.0 mol H2 mol/mol sugar was attained by the control. The contribution of this research to the field is that developing a novel technology for maximizing the generation of biohydrogen from biomass through the photobiostimulation of hydrogen-producing bacteria using laser irradiation. [ABSTRACT FROM AUTHOR]

The aim of this study was to explain by molecular pathways the kinetic differences between reuse water disinfection processes using UV-C radiation and OH• radicals. The Fenton reaction (which produces OH radicals) was found to be significantly more effective at inactivating of thermotolerant coliforms (TTC) than either H2O2/UV-C or direct UV-C, with constants of inactivation that were some 6- to 14-fold higher. The superiority of Fenton was attributed to the powerful action of OH• in disassembling the molecular structure of E. coli cell wall and inducing the collapse of the entire cell structure, as demonstrated via molecular mechanisms. Under optimized conditions, treatment of wastewater in a plant comprising an anaerobic hybrid reactor with intermittent sand filter followed by a Fenton process led to the removal of 97.2% TOC, 99.9% turbidity and 100% of TTC and the quality of the final effluent was appropriate for direct potable reuse. [ABSTRACT FROM AUTHOR]

The present study investigates the physico-chemical characteristics of the fresh leachate of household waste at the entrance of the technical landfill center (CET-Sour) of the city of Mostaganem. The leachate is treated using the up-flow anaerobic sludge blanket (UASB) technique. The amount of household and similar waste attained about 61,775 tons as of 2021 corresponding to a daily generation of 0.91 kg per capita. This waste was essentially composed of organic matter (63.5%), paper (12.5%), plastic (14.7%), metal (1.1%) and glass (1.5%). The amount of leachate produced during the low and high-water periods in the city of Mostaganem varied between a minimum of 40,870 L in December 2021 and a maximum of 127,930 L in August 2021. Physicochemical analysis of the leachates of the study area shows a high concentration of organic matter with a chemical oxygen demand (COD) of about 24,650 mg·O2/L and a pH of 4.47. Application of the UASB technique under the climatic conditions of the study area to the leachate before direct discharge into the environment resulted in a COD abatement of 94% and a near neutral pH (pH = 6.89). The results obtained show that the UASB technique is suitable for fresh leachate treatment and could be used as an efficient process to reduce pollutant load. [ABSTRACT FROM AUTHOR]

Removal of sulfide by gas stripping using biogas produced in an internal phase-separated reactor (IPSR) was evaluated during anaerobic treatment. The IPSR consisted of upper and lower segments with a gas–liquid partitioning (GLP) valve between the sections. Wastewater was fed to the upper segment in the first stage and then to the lower segment in the second stage. The GLP valve separated the liquid phase from the gaseous phase and supplied biogas from the lower segment to the upper segment. The IPSR and a control reactor were fed with synthetic wastewater and operated in parallel under an organic loading rate of 12 kg COD/(m3 day) at 35 °C. The sulfide concentration increased to 400–600 mg S/L, which is above the previously reported 50% inhibition level for methanogenic activity. The IPSR showed higher H2S removal performance than the control reactor and removed approximately twice the H2S as the control reactor at 400 mg S/L, indicating that it can be used for the stable treatment of wastewater containing high concentrations of sulfide. HIGHLIGHTS Sulfide removal was evaluated in an internal phase-separated reactor (IPSR).; The IPSR consisted of an upper segment (first stage) and a lower segment (second stage).; Sulfide in the upper segment was removed by biogas supplied from the lower segment.; Sulfide removal was higher in the IPSR than in the control reactor.; The IPSR had higher organic removal than the control reactor.;

The effluents of polymerization plants are acidic due to the use of sulfuric acid as flocculation agent and their wastewater contains high amounts of sulfate ions. In wastewater industry, several physical, chemical and biological treatment methods are used. The main purpose of this study is to examine the feasibility of anaerobic biological treatment of sulfate in industrial effluents by using sulfate-reducing bacteria. The research method is quantitative, and experiments and data collection from 2017-2020. The main variables of this research are temperature, effluent pH and the population of microorganisms. Experiments at two temperature levels of 25 and 60 oC and two different pHs, 7.5 and 8.5, were performed and four series of experiments were done. The results showed that by increasing the temperature of the solution from 25° to 60 °C at a concentration of 50 mg/L sulfate ion and a pH of 7.5, microorganisms showed 17.6% better performance. Also, the performance of microorganisms in anaerobic biological treatment at concentration of 50 mg/L of sulfate ion was 45.3% minimum and 49.9% at maximum. Comparison of experimental results at two different pHs of 7.5 and 8.5, indicates that at the same temperatures of 25 and 65°C, with increasing pH, the performance of microorganisms has improved by 16.4%. The efficiency of wastewater treatment increases 19.6% by changing pH from 7.5 to 8.5. Results showed that the correlation between temperature and sulfate ion concentration follows the 1st degree equation. Also, the weak pH environment provides suitable conditions for the removal of ions in the effluents, and the correlation between increasing the pH of the solution and decreasing the concentration of sulfate ions is a 2nd degree equation. Study showed that temperature and pH are the two effective factors in the process of biological treatment of effluents.

In this study, we aimed to explore the effect of anaerobic treatment on the contents and functions of bioactive components such as γ-aminobutyric acid (GABA) in yellow tea and to analyze the mechanism by which anaerobic treatment promotes GABA enrichment using metabolomics. We also analyzed the changes in related metabolism pathways. The results showed that the content of GABA in yellow tea was increased to 3.3 mg/g after anaerobic treatment, and the contents of the upstream and downstream amino acids related to GABA were changed correspondingly. Moreover, anaerobic treatment significantly increased the contents of total phenolics and total flavonoids in yellow tea. In vitro bioactivity evaluation showed that anaerobic treatment improved the free radical scavenging capacity, total antioxidant activity and inhibitory effect on the formation of glycosylation products of yellow tea, but had little effect on the ability of yellow tea to inhibit starch digestion enzymes. A total of 218 differential metabolites between fresh and GABA-rich tea, including amino acids, organic acids, flavonoids, nucleotides, and sugars. Pathway enrichment analysis demonstrated that the amino acid biosynthesis, tryptophan metabolism, flavonoid biosynthesis, and butyrate metabolism pathways were significantly regulated. Anaerobic treatment could regulate the GABA content in yellow tea by affecting the L-glutamate and succinic semialdehyde pathways. This study can provide a reference for the research and development of GABA-rich tea.

The search for cleaner and more sustainable energy sources is increasingly growing. Aligning this demand with another environmental problem, such as sewage treatment/disposal, is a strategic priority. In light of this, the aim of this study was to estimate the energy potential of sewage generated in the Brazilian state of São Paulo (SP) by using it to produce biomethane. The study also evaluated the viability of using this byproduct of sewage treatment (biomethane) as a substitute for natural gas (NG), as both of them have similar lower heat values. To do this, information was gathered regarding the population, gross domestic product per capita, sewage collected, and natural gas consumption for each of the state’s 645 cities, and, based on this, the sewage energy potential, the amount of NG to be substituted by biomethane, and the reduction in CO2 emissions were calculated. Moreover, in order to address a possible allocation of biomethane that could potentially be produced in each SP city and sent to currently NG-consuming cities, an optimization algorithm was proposed. The results indicated a sewage energy potential of 4.68 × 109 kWh/yr for the entire SP state, which would be enough to supply around 10% of the energy value of all the NG currently consumed. It was also observed that from 130 cities with NG consumption, 10 could produce enough biomethane to fully satisfy the natural gas demand. In the elected scenario of optimization, 291 cities were found to be capable of supplying the demand of 26 cities that currently use NG. The potential to reduce CO2 emissions is between 1.81 × 106 and 2.42 × 106 ton/yr, and this range could increase if sewage treatment coverage grows. Despite the challenges inherent in extrapolating a potential study to scenarios that require significative investment, the results obtained are useful for formulating public policies for decarbonization in the near future.

Hydrothermal carbonization (HTC) has developed considerably over the last 15 years and offers a viable alternative for the utilization of municipal and industrial organic waste such as sewage sludge. However, the technology has yet to establish itself as a valorization process for waste biomasses (2024) and is not yet a recognized state of the art. Nevertheless, the HTC technology could gain greater relevance in the future, especially as an alternative valorization pathway for sewage sludge. During HTC, significant amounts of HTC process water (PW) are produced as a byproduct. The process water is inorganically and organically polluted and has to be treated, as it would be a burden on water bodies and thus on the environment if left untreated. In the EU and specifically Germany, industrial wastewater producers like HTC-plant operators are obliged to treat their industrial wastewater before discharging it into the environment. In addition to a large amount of PW and its treatment to the required limits, the organic load and possible persistent and toxic substances pose major challenges for plant operators. Many proven processes from industrial wastewater treatment were transferred for the treatment of PW. Treatment of the PW in a manner that is industrially viable, economically viable, and efficient is crucial for the effective commercialization of HTC technology. In this, the challenges and opportunities of PW composition, management, and treatment, including legal aspects, are mainly discussed. Therefore, the legal framework in the European Union and specifically for Germany will be elaborated. Furthermore, different treatment pathways are also highlighted.

The growing population and increasing urbanization have led to a surge in domestic wastewater generation, posing significant challenges for effective and sustainable treatment. The present study demonstrates a novel and sustainable approach for the onsite treatment of domestic wastewater using an integrated settler-based biofilm reactor (ISBR) with efficient biogas generation. The ISBR provides an optimized environment for the growth of biofilm, facilitating the removal of organic pollutants and pathogens. Moreover, the ISBR enables the recovery of a valuable resource in the form of biogas, thus enhancing the overall utility of the treatment process. The performance of the ISBR was comprehensively evaluated at laboratory scale through treating the actual domestic wastewater generated from the hostel of Manipal University Jaipur. The ISBR system was operated under an ambient environment at a hydraulic retention time (HRT) of 24 h. The results demonstrated remarkable efficiency in terms of chemical oxygen demand (COD), total suspended solids (TSS), and coliforms removal, with average removal efficiency being more than 90%. According to the COD mass balance analysis, 48.2% of the influent COD was recovered as bioenergy. The chromatogram revealed a high percentage of methane gas in the collected biogas sample. The field emission scanning electron microscope (FESEM) analysis of the accumulated sludge in the ISBR system depicted the morphology of methanogenic bacteria. Both the experimental and theoretical results confirmed the feasibility and sustainability of the ISBR system at the onsite level. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Tea Science is the property of Journal of Tea Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Biohydrogen has significant feasibility since biological processes are much less energy intensive compared with electrolysis and thermo-chemical processes. Biological processes and bacterial fermentation are considered as the most environmentally friendly alternatives for satisfying future hydrogen demand. Biohydrogen production from biomass is considered profitable as biomass is abundant, cheap, and biodegradable. The combustion of H2 with O2 produces water as its only product: Unlike other fuels, the combustion of H2 does not produce CO2, CO, NOx, or SO2. Therefore, H2 is an environmentally friendly fuel. The objective of this study is to increase biohydrogen production from biomass using nanotechnology. In this study, it is hypothesized that the biostimulation of hydrogen-producing purple non-sulfur (PNS) bacteria through the addition of nutrients in form of nanomaterials can enhance the bioresponses of such bacteria, where this leads to increase biohydrogen production from biomass. A biohydrogen production system and a model of photobioreactor were manufactured and installed. Food wastes were collected from kitchen leftovers of different fast-food suppliers and were used in this study as feedstocks for biohydrogen production. The production process was conducted as following: addition of 50 mg l-1 of nickel nanoparticles to the bacterial inoculum and then mixing them with biomass and water by a ratio of 0.5:1:2 which were then kept in the photobioreactor exposed to white light emitting diodes (LEDs) with a luminous flux of 3600 lumen and at 30 ℃ for 14 days with mixing for 5 min every 30 min to produce biohydrogen. The results showed that the maximum biohydrogen yield was 40.7 mol H2/mol sugar (2.68 times control) when Ni nanoparticles were added. Besides, during the active production period the H2 percentages ranged from 48.0% to 51.7% when Ni nanoparticles were added which were higher by 15% than the control. It was concluded that the addition of nanomaterials leads to biostimulate the bacterial cells and enhance their activity and growth rate and, therefore, increase biohydrogen production from biomass. [ABSTRACT FROM AUTHOR]

Treatment of textile wastewater with domestic wastewater as co-substrate was investigated in this study. Combined textile and domestic wastewater at different mixing ratios (100:0, 80:20, 60:40) was treated under anaerobic reactor. The influence of residence time, textile wastewater fraction and initial pH were determined in view of COD and color removal. Response Surface methodology (RSM) with Box–Behnken design (BBD) was employed to determine conditions for higher simultaneous removal of COD and color. The highest simultaneous removal of COD and color were satisfied at initial pH of 8.6, residence time of 9 days while textile and domestic wastewater ratio was 77:23. The highest removal efficiencies realized were 70% and 72% for color and COD respectively. In general, longer residence time and higher initial pH favored higher simultaneous removal of COD and color. Furthermore, textile wastewater fraction in range of 0.65 – 0.8 favored simultaneously high COD and color removal. Therefore, co-digestion of textile and domestic wastewater at specific ratio is a novel finding that can be further developed for treating textile wastewaters. Moreover, this technology is a promising approach to enhance biological treatment of textile wastewater.

Medium chain carboxylic acids (MCCAs, e.g., caproic acid, caprylic acid, etc.) with 6–12 carbon atoms are valuable platform chemicals produced from organic waste via microbial chain elongation metabolism named as reversed β-oxidation and fatty acid-biosynthesis cyclical pathway. Recently, many articles reported that electricity could not only serve as the external electron donor and provide the reduction equivalent required for chain elongation but also regulate the microbiome structure and metabolic behaviors to promote MCCAs formation. Electricity-steering MCCAs bioproduction has become an appealing technique to valorize low-value organic waste, paving an alternative pathway for net-zero carbon emission energy systems and sustainable socio-economic development. However, the MCCAs' bioproduction from organic waste steered by electric field has not been comprehensively reviewed. From a systematical analysis of publicly available literature, we first covered the basic working principle, fermentation architecture, functional microflora, and metabolic pathway of MCCAs production driven by electricity. The strategies of substrate modulation, applied voltage/current regulation, electrode optimization, and microbial cooperation and stimulation for boosting electricity-driven MCCAs bioproduction are then scrutinized and extensively discussed. Ultimately, the pressing knowledge gaps and the potential path forward are proposed to provide pointers for consistently higher MCCAs yield and the transition from laboratory to market. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Slaughterhouse wastewater is characterized by high concentrations of organic matter. This creates a need to explore methods for its treatment before discharge. This study evaluated the efficiency of an integrated treatment process consisting of a laboratory-scale upflow anaerobic sludge blanket reactor and a pilot-scale horizontal subsurface flow wetland. This treatment was used for (i) the removal of organic matter through anaerobic–aerobic microbiological processes, (ii) the conversion of organic matter from hydraulic processes, and (iii) for bioremediation and phytoremediation. The treatment system was evaluated at hydraulic retention times (HRTs) of 7.5, 5.0, and 2.5 d; during the investigation, the influence of the HRTs on the removal efficiency of the system was evaluated. High efficiencies of 85% and 75% were obtained for CODT and BOD, respectively, at an HRT of 7.5 d. The highest overall efficiency for the removal of total solids was observed at an HRT of 2.5 d. The results obtained confirm the feasibility of implementing the suggested system as an alternative for the adequate and sustainable treatment of slaughterhouse wastewater, and the system can be applied to slaughterhouses with similar conditions to those in this study.

BACKGROUND: Dynamic modeling of the anaerobic treatment of agro‐industrial waste can help determine optimal operating conditions to maximize the process performance. For this, it is necessary to select an appropriate model and adapt it to the specific conditions of the substrate. In this work, a simple unstructured kinetic model for the anaerobic treatment of different agro‐industrial waste is proposed. The proposed model considers the three most relevant stages of anaerobic digestion (AD) and can be adapted for the treatment of different substrates, modes of operation (batch or continuous), and/or generated products (VFA or methane production), thus requiring a minimum of process macroscopic measurements. RESULTS: To evaluate the scope of the model, two case studies were analyzed: (i) methane production from tequila vinasse and agave hydrolysates, and (ii) volatile fatty acids (VFA) and biogas production from raw cheese whey. For each case, parameter estimations were performed using the Levenberg – Marquardt algorithm, which yielded a simplified model with high determination coefficients (R2 > 0.95). Moreover, the kinetic parameters estimated were consistent physically and statistically. CONCLUSION: Numerical results show that the proposed model can satisfactorily describe the dynamic behavior of the key variables of the three types of agro‐industrial waste evaluated. Therefore, the proposed model might be advantageous to determine the conditions that maximize performance without risking process stability. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

UASB (upflow anaerobic sludge blanket) reactors have been recognized as a viable option for sewage treatment. However, in order to improve the UASB effluent quality, some type of post-treatment must be implemented. The aims of this study were (i) to establish a start-up methodology of a full-scale anaerobic–aerobic system treating sewage, (ii) to evaluate the concentrations of different constituents in the influent and effluent of the anaerobic and aerobic reactors as well as the removal efficiencies in every step of the system, and (iii) to define relevant operative aspects of the anaerobic and aerobic reactors. The Tunja (Colombia) wastewater treatment plant consists of three modules with preliminary treatment followed by UASB reactors with post-treatment of activated sludge. The results of this investigation showed that the effluent system meets the Colombian environmental legislation with average removal efficiency values of BOD (88 +/− 5%), COD (87 +/− 4%), and TSS (94 +/− 5%). The UASB reactor start-up was conducted without an inoculum, requiring a period of 120 days. The evaluation of the combined systems was conducted over 300 days. Moreover, a methodology to operate the system during and after the start-up of the anaerobic reactor was defined. It was demonstrated that the anaerobic effluent can deteriorate the sludge in the aerobic tank. In order to avoid this, important operational aspects must be considered during the operation of the system, such as the implementation of a raw wastewater bypass higher than 15% and monitoring of the anaerobic effluent settleable solid concentration (<0.3 mL/L). [ABSTRACT FROM AUTHOR]

[Objectives] The research was to explore the antifungal effects of citronellal, Wintergreen oil and their composite essence on Pénicillium citrinum. [Methods] The inhibition zones of citronellal, Wintergreen oil and their composite essence against P. citrinum were determined by disk diffusion method, and the growth of inhibition zone plate was observed. The fumigation fungicidal rate of fungi-bearing rice paper within 7 d was determined by plate counting method. [Results] Citronellal had strong antifungal effect, and Wintergreen oil could slow down the growth rate of P. citrinum. The combination of citronellal and Wintergreen oil had a synergistic effect. As fumigants, both citronellal and composite essence had fungicidal rates up to 100% within 7 d. Combined with anaerobic treatments, all the three essential oils could improve the fungicidal efficiency. The adsorbent in deoxidizing agent would adsorb the essential oils, so that their fumigation had a certain slow release effect. [Conclusions] This study can provide a more friendly and efficient method for the prevention and control of cultural relics mold. [ABSTRACT FROM AUTHOR]

Given the large quantities and considerable treatment costs, the simultaneous recovery of bioenergy and bioresources in the waste activated sludge (WAS) treatment process to reduce the economic burden and change the treatment model from energy input to sustainable treatment has gained increasing attentions. Freezing/thawing pretreatment, a green and cost-effective method to strengthen sludge floc disintegration, has been widely used in sludge management to recover resources and energy. Nevertheless, a comprehensive summary and assessment of applying this strategy is still lacking. Accordingly, to fill this gap, the progress and breakthroughs of the impacts of F/T pretreatment on energy (including methane, hydrogen and electricity) and resources (including short-chain fatty acids (SCFAs) and phosphorus) recovery during anaerobic digestion (AD), anaerobic fermentation (AF) and microbial fuel cells (MFCs) and related influencing factors are overall outlined for the first time. Particularly, the potential mechanisms of F/T pretreatment in improving the recovery of methane, hydrogen, electricity, SCFAs and phosphorus from AD, AF and MFCs are deeply revealed, respectively. Furthermore, this work is the first to systematically summarize the additional benefits of the additional benefits including promoting dewatering performance and pathogens inactivation of digestate and/or fermented sludge after applying F/T pretreatment. Finally, some shortcomings of current research on sludge treatment based on F/T pretreatment and the research directions that need to be focused on to promote its futural application are discussed. Our work aims to offer an reference and support in theory and technology for applying F/T pretreatment in energy and resource recovery from WAS. [Display omitted] • Underlying mechanisms of F/T pretreatment disintegrating sludge floc are reviewed. • Enhanced energy recovery including methane, hydrogen and electricity can be achieved effectively by F/T pretreatment. • The recovery of SCFAs and phosphorus from sludge can be improved greatly with F/T pretreatment-based treatment. • F/T pretreatment can promote the dewatering and pathogens inactivation of digestate and/or fermented sludge. [ABSTRACT FROM AUTHOR]

[Display omitted] • Food delivery boxes are tested for aerobic disintegration and anaerobic degradation. • Boxes made of paper only or with coatings (including polylactic acid) are analysed. • Paper is highly suitable for biological treatments behaving similarly to food waste. • Aerobic disintegration of coated boxes is much slower than that of paper only boxes. • Undigested polylactic acid coating is found in anaerobic semi-continuous tests. This study evaluated the fate of food delivery boxes when subjected to biological treatments, reproducing at the lab-scale the conditions of full-scale plants. Four paper-based boxes were composted: two made of paper only, one coupled with polylactic acid (PLA), and one with a barrier coating. One paper only box and the box with PLA were also investigated for their anaerobic degradability with biochemical methane potential (BMP) and semi-continuous tests. During composting, the boxes were not recognisable inside the compost after four (paper only boxes), eight (box with PLA), and twelve (box with barrier coating) weeks. In BMP tests, the paper only box showed a degradability similar to that of food waste (92 %), while the box with PLA degraded only at 76 %. Furthermore, undigested pieces of PLA were found in semi-continuous tests. Accordingly, paper resulted suitable for biological treatments, while the presence of PLA or other barrier coatings can be critical. [ABSTRACT FROM AUTHOR]

[Display omitted] • Adding iron salts improved rural wastewater treatment by anaerobic baffled reactor. • Feammox can play a role in removing ammonium and total nitrogen in bioreactors. • Phosphorus was removed via vivianite formation with sludge production minimized. • Iron chemistry-induced nutrient removal saved cost by reducing aeration. An iron-retrofitted anaerobic baffled reactor (ABR) system was developed for the effective treatment of rural wastewater with reduced maintenance demand and aeration costs. Average removal efficiencies of chemical oxygen demand, total nitrogen and total phosphorus of 99.4%, 62.7% and 92.6% were achieved respectively, when the ABR system was operating at steady state. With effective bioreduction of FeIII in the anaerobic chambers, phosphorus was immobilized in the sludge as vivianite, the sole phosphorus-carrying mineral. The FeIII in the recirculated sludge induced Feammox in the ABR reactor, contributing 14.8% to total nitrogen removal. Biophase separation and enrichment of microorganisms associated with iron and nitrogen transformations were observed in the system after Fe dosing, which enhanced the removal of pollutants. The coupling of Feammox and vivianite crystallization to remove nitrogen and phosphorus in an iron-retrofitted ABR would appear to be a promising technology for rural wastewater treatment. [ABSTRACT FROM AUTHOR]

Anaerobically-treated palm oil mill effluent (POME) still has unacceptable properties for water recycling and reuse, with an unpleasant appearance due to the brownish color caused by tannins and phenolic compounds. This study proposes an approach for treating anaerobically-treated POME for water recycling by combining organic precipitation, electrocoagulation (EC), and ion-exchange resin, followed by reverse osmosis (RO) membrane filtration in series. The results indicated that the organic precipitation enhanced the efficiency of EC treatment in reducing the concentrations of tannins, color, and chemical oxygen demand (COD) of the anaerobically-treated POME effluent, with reductions of 95.73%, 96.31%, and 93.96% for tannin, color, and COD, respectively. Moreover, organic precipitation affected the effectiveness of Ca2+ and Mg2+ ion removal using ion exchange resin and RO membrane filtration. Without prior organic precipitation, the ion-exchange resin process required a longer contact time, and the RO membrane filtration treatment was hardly effective in removing total dissolved solids (TDS). The combined process gave a water quality that meets the criteria set by the Thailand Ministry of Industry for industrial boiler use (COD 88 mg/L, TDS <0.001 mg/L, water hardness <5 mg-CaCO 3 /L, and pH 6.9). [Display omitted] • The integrated process comprised organic precipitation, EC, ion-exchange resin, RO. • The organic precipitation of tannins in POME was performed using pig blood proteins. • The efficiency of COD removal from anaerobically-treated POME was 98.5%. • The integrated treatment process increased water hardness removal to 99%. • The properties of treated POME met the criteria for industrial boiler use. [ABSTRACT FROM AUTHOR]

Textile industries are among the primary contributors of water pollution. Treatment of textile wastewater is very important before discharging it to the environment. In the present study, laboratory-scale anaerobic batch reactors were used for co-treatment of a mixture of textile and domestic wastewater at 37 °C. The objective of this work was to investigate optimum conditions for the anaerobic co-digestion of textile wastewater and domestic wastewater. Domestic wastewater as a carbon source to enhance treatment of textile wastewater in color and other pollutants removal was examined. Textile and domestic wastewater were mixed at different proportions to make a total volume of 500 mL. Proportions of domestic wastewater and retention time were two main factors studied in influencing pollutant removal efficiency. Optimum conditions for removal of pollutants were 18 days' residence time at 60 and 40% textile and domestic wastewater respectively. The removal efficiencies were 52.8, 58.3 and 51.6% for Color, BOD and COD, respectively. Phosphorus (PO43−), Ammonium (NH3-N) and Nitrate (NO3-) increased at 78.5, 49 and 87% respectively. However, the concentration levels were above Tanzania Bureau of Standards (TBS) discharge limits. Post treatment is suggested to achieve standard discharge limits. HIGHLIGHTS Degradation of dyes in textile wastewater.; Co-digestion of textile and domestic wastewater.; Degradation of organic matter in textile wastewater.; Reduce water pollution from textile wastewater effluents.; Ecological protection of water bodies.;

This study evaluated and compared the performance of three highly praised high rate anaerobic bioreactors (HRABs), including the expanded granular sludge bed (EGSB) bioreactor, the static granular bed reactor (SGBR), and the down-flow expanded granular bed reactor (DEGBR), for the treatment of poultry slaughterhouse wastewater (PSW) which is characterized by a high concentration in oil and grease, suspended solids, and nutrients. These three bioreactors were operated under mesophilic conditions and followed a similar operational methodology, which consisted of increasing the organic loading rate (OLR) as the bioreactor responded positively to fluctuating organic loads. The response to the fluctuations of the bioreactors was evaluated with respect to the removal of the organic matter contained in PSW at high throughput rate. This study revealed that the three bioreactors performed differently. This dissimilarity in performance was associated with the difference in the configuration of each reactor and the capacity of maintaining a high performance at increased levels of OLR. These configurations are specifically described in this study. Of the three bioreactors that were investigated, the DEGBR performed the best with total chemical oxygen demand (tCOD), biological oxygen demand (BOD5) and fats, oil, and grease (FOG) maximum removal percentages of 99.6%, 99.9% and 99.4%, respectively, for a maximum OLR of 38.9 gCOD/L.day. While the EGSB also provided appreciable results with 99.1%, 99.5% and 97%, for the maximum removal efficiency of tCOD, BOD5 and FOG, respectively. At last, the SGBR achieved tCOD, BOD5 and FOG maximum percentage removal of 97.6%, 99.2% and 97.7%, respectively. [ABSTRACT FROM AUTHOR]