Effect of Electrolysis on Activated Sludge during the Hydrolysis and Acidogenesis Stages in the Anaerobic Digestion of Poultry Manure

This paper focuses on the study of the effect of electrolysis on activated sludge in amicrobial electrolysis cell (MEC) under the anaerobic digestion of poultry manure. This study was conducted using a bioreactor design with and without electrodes (conventional condition). Measurements of pH, redox potential (ORP), and total dissolved solids were carried out, as was the microscopy of activated sludge during treatment and gasometry. There was an increase in the yields of CH4 and CO2 compared to conventional conditions. Thus, on the 14th day, there was an increase in the CH4 yield to 35.1% compared with the conventional conditions - 31.6% - as well as in the CO2 yield to 53.5% compared with the cell without electrodes - 37.7%. Visually, the microscopy of anaerobic activated sludge showed changes in the aggregation process itself, with the formation of cells of clusters of microorganism colonies with branches of a delineated shape. ORP fluctuations were related to the process of the dissociation into ions during the passage of an electric current through the electrodes, and were observed before and after the inclusion of a current into the system. A model of the effect of electrolysis during anaerobic digestion was developed, taking into account the influencing factors on the condition of the activated sludge

Integration of Processes of Radionuclide-Contaminated Territories Decontamination in the Framework of their Ecological-Socio-Economic Rehabilitation

Large-scale disasters at nuclear power plants (NPPs) and their consequences are still the subject of discussion by the world scientific community, which makes mankind recognize the unsolved problem of radiation pollution. Accordingly, the search for new effective biocomposite materials with high sorption capacity to eliminate harmful effects associated with radiation contamination of large territories is an urgent task on a global scale. This paper is devoted to the study of the decontamination processes of the areas contaminated with radionuclides, the search for new mechanisms of fixation of radionuclides and heavy metals in the soil using the matrix material of different origin. In order to intensify the process of radionuclide fixation in the soil-plant system the method consisting of introducing into the soil the organic-mineral biocomposite based on sewage sludge and phosphogypsum after anaerobic fermentation was proposed. It is necessary to further study the processes of sorption and radionuclides solubilization due to complexation with organic agents present in matrix materials of different nature. The mechanisms of radionuclide and heavy metal fixation using matrix material of different origin were analyzed and a general model was formed. The direction of integration of radionuclide-contaminated soil decontamination technologies into the process of ecological, social, and economic development of the territories under rehabilitation after the accidents at the Chernobyl NPP and Fukushima-1 NPP is proposed

Rationale for the Combined Use of Biological Processes and AOPs in Wastewater Treatment Tasks

This paper aims to form a unified concept of the integrated use of different wastewater treatment methods to form a resistant biological treatment stage of technological systems under the influence of such toxic factors as antibiotics and surfactants. The processes of mechanical treatment, ozonation, UV irradiation, and electrolytic anodic oxidation were implemented in an electrotechnological wastewater treatment facility. Wastewater treatment quality was determined by the concentration of nitrogen compounds in aqueous solutions according to the method of Lurie. Biodiagnostics of the investigated activated sludge via surfactant action was carried out at polyethylene oxide concentrations of 10, 30, and 50 mg/dm3. As a result of experiments on wastewater treatment after aquaculture, an improvement in the reduction of pollutants only by the indicator “nitrate concentration” was determined: by 20% after anodic oxidation, and by 15% after photolysis. At almost all surfactant concentrations studied, the activated sludge was not completely recovered, which was expressed in a decrease in its quantity and in the inability to aggregate flakes of activated sludge. The diameter of the growth retardation of the standard disk with antibiotic (amoxiclav) by the accumulative culture of activated sludge was 17.3 2 mm at a concentration of 4 mg/dm3 and 31.3 3 mm at a concentration of 6 mg/dm3. In the process of studying the state of the activated sludge’s biocenosis under the influence of such toxicants, several regularities were revealed. The directions of using combined approaches of water treatment and wastewater treatment were defined. The structural model of treatment facilities using aerobic and anaerobic bioprocesses together with advanced oxidative technologies was substantiated

Intensification of Waste Valorization Techniques for Biogas Production on the Example of Clarias gariepinus Droppings

This study aims to evaluate the process of biogas production from the droppings of Clarias gariepinus under intensification of methanogenesis using electrolysis pretreatment and electrofermentation in comparison with the addition of stimulating substances (humates and zeolites). For the realization of a series of experiments, laboratory installations of electrolysis and electro fermentation were developed. The following parameters were monitored: biogas composition, chemical oxygen demand, redox potential, hydrogen potential, nitrates, ammonia–ammonium, and nitrites. A taxonomic classification and review of the metabolic pathways were performed using the KEGG, MetaCyc, and EzTaxon databases. The stimulation of biomethanogenesis in the utilization of catfish droppings by the introduction of additional electron donors—exogenous hydrogen (electro fermentation)—was confirmed. The electro-fermentation process released 4.3 times more methane compared to conventional conditions and stimulant additives and released 1.7 times more with electrolysis pretreatment. The main metabolic pathways of electron acceptor recruitment using bioinformatic databases are highlighted, and models of CO2 transformation involving exogenous hydrogen along the chain of metabolic reactions of methanogenesis are generated. The summary model of metabolic pathways of methanogenesis are also proposed. Based on the results of the present and previous studies, two technological solutions are proposed to implement the process of anaerobic treatment intensification of excreta of the clariid catfish. Additional studies should include the optimization of the operation mode of electro-fermentation and electrolysis pretreatment of the substrate during the aquacultivation process

Comparison of sorption efficiency of natural and MnO2 coated zeolite for copper removal from model solutions

Removal of heavy metals from the environment is important for living beings. The present work investigates the applicability of the natural and MnO2 - coated zeolite as sorbent for the removal of copper from synthetic solutions. Batch experiments were carried out to identify the influence of initial pH and concentration in the process of adsorption. A maximum removal efficiency of Cu(II) was observed in 10 mg/L for natural (95.6%) and modified (96.4%) zeolite, where the values was almost identical, but at concentration of 500 mg/L was the removal efficiency of modified zeolite three times higher. Based on the correlation factors R2, the Langmuir isotherms better describe the decontamination process than Freundlich. The optimum pH value was set at 5.0

Biophysical and electrochemical studies of protein-nucleic acid interactions

This review is devoted to biophysical and electrochemical methods used for studying protein-nucleic acid (NA) interactions. The importance of NA structure and protein-NA recognition for essential cellular processes, such as replication or transcription, is discussed to provide background for description of a range of biophysical chemistry methods that are applied to study a wide scope of protein-DNA and protein-RNA complexes. These techniques employ different detection principles with specific advantages and limitations and are often combined as mutually complementary approaches to provide a complete description of the interactions. Electrochemical methods have proven to be of great utility in such studies because they provide sensitive measurements and can be combined with other approaches that facilitate the protein-NA interactions. Recent applications of electrochemical methods in studies of protein-NA interactions are discussed in detail

Polymer materials: bibliographic data analysis and trend detection

Alternatives to waste management methods include the reorganization, recycling, and creation of environmentally friendly biodegradable polymer materials based on renewable resources, plant, and textile waste. The goal of this study is to analyze bibliographic data and identify trends in research on polymer materials of different genesis, with particular attention to research on the production and use of biopolymers. VOSviewer v.1.6.15 is used to present the analysis results. Environmental impact areas in the life cycle of traditional polymers have been analyzed. The network of main bioplastics clusters is visualized within the framework of modeling the dependencies on the main keywords in the analysis of the dynamics of publication activity, the main trends in the development of new biodegradable materials are revealed. A comparative review of the environmental impact of different types of bioplastics is made by the life cycle assessment method

Rationale for the Combined Use of Biological Processes and AOPs in Wastewater Treatment Tasks

This paper aims to form a unified concept of the integrated use of different wastewater treatment methods to form a resistant biological treatment stage of technological systems under the influence of such toxic factors as antibiotics and surfactants. The processes of mechanical treatment, ozonation, UV irradiation, and electrolytic anodic oxidation were implemented in an electrotechnological wastewater treatment facility. Wastewater treatment quality was determined by the concentration of nitrogen compounds in aqueous solutions according to the method of Lurie. Biodiagnostics of the investigated activated sludge via surfactant action was carried out at polyethylene oxide concentrations of 10, 30, and 50 mg/dm3. As a result of experiments on wastewater treatment after aquaculture, an improvement in the reduction of pollutants only by the indicator “nitrate concentration” was determined: by 20% after anodic oxidation, and by 15% after photolysis. At almost all surfactant concentrations studied, the activated sludge was not completely recovered, which was expressed in a decrease in its quantity and in the inability to aggregate flakes of activated sludge. The diameter of the growth retardation of the standard disk with antibiotic (amoxiclav) by the accumulative culture of activated sludge was 17.3 ± 2 mm at a concentration of 4 mg/dm3 and 31.3 ± 3 mm at a concentration of 6 mg/dm3. In the process of studying the state of the activated sludge’s biocenosis under the influence of such toxicants, several regularities were revealed. The directions of using combined approaches of water treatment and wastewater treatment were defined. The structural model of treatment facilities using aerobic and anaerobic bioprocesses together with advanced oxidative technologies was substantiated

Sulfur Utilization in the Systems of Biological Wastwater Denitrification

This paper focuses on the study of the possibility of using mineral carriers from sulfur (bio-sulfur/elementary sulfur) in anaerobic wastewater treatment systems under autotrophic denitrification conditions. The theoretical aspects of the work are based on the biochemical formalization of the studied processes using the systemic-synergetic approach for the description of the patterns of autotrophic denitrification microorganisms based on the principles of autocatalysis of natural systems. Special software was used in the work to identify the necessary ecological and trophic groups of microorganisms and implement the schemes of trophic interactions in association of denitrification microorganisms. The taxonomic classification was assigned based on the KEGG database (Kyoto Encyclopedia of Genes and Genomes). Bio-filtration set-up system was formed for carrying out the process wastewater denitrification with using bio-sulfur and gaseous sulfur. The filtration method is used under anaerobic conditions along with immobilization on the carrier based on sulfur autotrophic denitrifying bacterial species such as Thiobacillus denitrificans and Thiomicrospira denitrificans. Thus, sulfur conversion leads to the reduction of nitrates to nitrites and, ultimately, the release of molecular nitrogen. The mechanisms of sulfur conversion in natural ecosystems make it possible to conclude its expediency of use it as a sorption sulfur-containing mineral carrier in wastewater purification systems with further conversion to an organic form (with microbial cell carbonate). The interactions pathways model in the association of heterotrophic and autotrophic denitrification bacteria in the process of wastewater and sewage sludge purification was formed under condition of elementary sulfur presence. Energetic and synthesis reactions for an autotrophic denitrification were described. The implementation of wastewater treatment systems with autotrophic denitrification process use will provide an opportunity to expand the application scope of by-products such as gaseous sulfur and bio-sulfur that currently minimal recycling in traditional industrial processing.У статті основна увага приділяється вивченню можливості використання мінеральних носіїв з сірки (біо-сірки / елементарної сірки) в системах анаеробного очищення стічних вод в умовах автотрофної денітрифікації. Теоретичні аспекти роботи засновані на біохімічній формалізації процесів очищення з використанням системно-синергетичного підходу для опису закономірностей автотрофних денітрифікуючих мікроорганізмів на основі принципів автокаталізу природних систем. Спеціальне програмне забезпечення використовувалося для визначення необхідних екологічних і трофічних груп мікроорганізмів та для реалізації схем трофічних взаємодій в асоціаціях мікроорганізмів-денітрифікаторів. Таксономічна класифікація призначена на основі бази даних KEGG (Кіотська енциклопедія генів та геномів). Була розроблена система біофільтрації для проведення денітрифікації модельних стічних вод з використанням біо-сірки і газової сірки. Метод фільтрації використовується в анаеробних умовах з іммобілізацією на носії з сірки автотрофний денітрифіціруючих бактеріальних видів Thiobacillus denitrificans і Thiomicrospira denitrificans. Трансформації сірки цими мікроорганізмами призводить до відновлення нітратів і до вивільнення молекулярного азоту. Механізми конверсії сірки в природних екосистемах дозволяють зробити висновок про доцільність використання її як сорбційного сірковмісного мінерального носія в системах очищення стічних вод з конверсією в органічну форму (з карбонатом мікробних клітин). Модель шляхів взаємодії в асоціації гетеротрофних і автотрофних денітрифікаційних бактерій у процесі очищення стічних вод і мулових осадів була сформована за умови присутності елементарної сірки. Описано енергетичні реакції і реакції синтезу для автотрофної денітрифікації. Впровадження систем очистки стічних вод з використанням процесу автотрофної денітрифікації дасть змогу розширити сферу застосування ряду побічних продуктів, таких як газоподібна сірка та біо-сірки, які в даний час мінімальні для традиційної промислової переробки

Remediation of Soil Contaminated with Heavy Metals

Стаття присвячена дослідженню прикладних аспектів рекультивації грунтів, зокрема процесу зв’язування важких металів та інтенсифікації вирощування грунтового мікробіома з використанням різних органічно-мінеральних композицій.: біогенний композит, який є продуктом анаеробного перетворення осадів стічних вод і фосфогіпсу; органічно-мінеральний компост на основі суміші фосфогіпсу, суперфосфату і гумусу великої рогатої худоби; та комбінацію суміші гумату натрію і суперфосфату. Була проведена інтеграція теоретичних і експериментальних принципів в синергетичний аналіз взаємозв’язків у системі "об’єкт – предмет дослідження" при вивченні динаміки змін форм знаходження важких металів у грунті. Відсотковий вміст мобільних форм важких металів, що виділяються екстрагентом від їх питового вмісту до і після обробки грунту органічно-мінеральними композиціями визначені з використанням спектрофотометричним методом. Здійснено порівняння ефективності обробки грунту. Використання методів математичної статистики дозволило довести кореляційний зв’язок між динамікою значень окислювальної здатності біомаси для біома грунту і швидкостю окислення субстрату для різного вмісту біокомпозиту.The paper is focused on the research of the applied aspects of soil remediation, in particular the process of heavy metals (HM) binding and intensifying the cultivation of a soil microbiome using various organic-mineral compositions: biogenic composite, which is the product of anaerobic transformation of sewage sludge and phosphogypsum; organic-mineral compost, based on a mixture of phosphogypsum, superphosphate and cattle humus; and a combination of a mixture of sodium humate and superphosphate. The integration of theoretical and experimental principles in the synergy analysis of the interrelations in the system "object – subject of research" in the study of the dynamics of changes in the forms of HM finding in the soil was carried out. The percentage content of the mobile forms of HM released by the extractant from their gross content before and after the treatment of the soil with organic-mineral compositions was determined with the spectrophotometric method using. The comparison of the soil processing efficiency was determined. Correlation relations of the dynamics in the biomass oxidative ability values for the soil biome and the rate of the substrate oxidation was proved over time treatment with different doses of the biocomposite with using of mathematical statistics methods