Research trends on nutrient management from digestates assessed using a bibliometric approach

Anaerobic digestion is often applied for biological conversion and valorization of organic waste, waste water and other biomass sources as renewable energy and biofuel in the form of biomethane. Composition of the material remaining after digestion, or digestate, is highly dependent on processed feedstocks. This by-product is usually rich in nutrients such as nitrogen and phosphorus, so it is potentially reusable as fertilizer or nutritive broth in agricultural systems. Alternatively, the digestate may need post-treatment based on nutrient removal or recovery strategies. The use of life-cycle assessment tools is becoming popular to analyze nutrient handling scenarios. This study reviews, through a bibliometric-based approach, the research outputs and global trends in the area of knowledge of nutrient management from digestates in the last 30 years, 2017 included. Documentary production followed an upward trend, with a relative productivity in the last 3 years greater than 37% of the total number of appeared publications. China, USA and Spain were the three most prolific countries. The particular interest in nutrient management alternatives and its evolution were identified. Trends for promoting sustainability include low environmental impact, holistic agro-energy solutions, reduced consumption of resources during digestate processing, and circular economy scenarios based on concepts such as (bio)refinery and recovery of valuable and marketable products.Postprint (published version

Recovery of phosphorus from waste water profiting from biological nitrogen treatment: Upstream, concomitant or downstream precipitation alternatives

Mined phosphate rock is the largest source of phosphorus (P) for use in agriculture and agro-industry, but it also is a finite resource irregularly distributed around the world. Alternatively, waste water is a renewable source of P, available at the local scale. In waste water treatment, biological nitrogen (N) removal is applied according to a wide range of variants targeting the abatement of the ammonium content. Ammonium oxidation to nitrate can also be considered to mitigate ammonia emission, while enabling N recovery. This review focuses on the analysis of alternatives for coupling biological N treatment and phosphate precipitation when treating waste water in view of producing P-rich materials easily usable as fertilisers. Phosphate precipitation can be applied before (upstream configuration), together with (concomitant configuration), and after (downstream configuration) N treatment; i.e., chemically induced as a conditioning pre-treatment, biologically induced inside the reactor, and chemically induced as a refining post-treatment. Characteristics of the recovered products differ significantly depending on the case studied. Currently, precipitated phosphate salts are not typified in the European fertiliser regulation, and this fact limits marketability. Nonetheless, this topic is in progress. The potential requirements to be complied by these materials to be covered by the regulation are overviewed. The insights given will help in identifying enhanced integrated approaches for waste water treatment, pointing out significant needs for subsequent agronomic valorisation of the recovered phosphate salts, according to the paradigms of the circular economy, sustainability, and environmental protection.info:eu-repo/semantics/publishedVersio

マイクロナノバブルを用いたH2とCO2からメタンへの生物的変換

筑波大学 (University of Tsukuba)201

Engineering and microbial aspects of Anammox process in wastewater treatment

Removal of nitrogen is mandatory in modern wastewater treatment plant (WWTP) due to its toxicity to both human and the ecosystem. A high level of nitrogen may cause eutrophication in aquatic system. Autotrophic nitrogen removal which combines partial nitritation and Anammox is an attractive technology which is suitable for high Ammonium strength wastewater with low organic carbon content. However the extreme slow growth of the Anammox bacteria with doubling time of 9-13 days hinders its wide full scale application. The aim of this research was to investigate the feasibility and operational strategy of Anammox enrichment from conventional aerobic sludge (Reactor ASR), denitrification sludge (Reactor DSR) and anaerobic sludge (Reactor ANR) using sequencing batch reactor (SBR). Anammox process was successfully established in DSR with a total nitrogen removal of approximately 80% under strict oxygen control after 150 days which is confirmed by chemical composition of the influent/effluent as well as microbial analysis. Under the same operational condition, ANR reached only 20-30% total nitrogen removal. With a shorter hydraulic retention time (HRT) and insufficient oxygen control, ASR reached 50-60% total nitrogen removal after 240 days. All the reactors experienced fluctuating performances during the enrichment process, which is believed to be the consequence of inhibitory factors such as dissolved oxygen, free nitrite and free ammonia as well as undesirable coexisting bacteria which compete for the same substrate. The denaturing gradient gel electrophoresis (DGGE) band from the amplified DNA samples extracted from ASR during different enrichment stage shows a clear evolution of the microbial composition. Extracellular polymeric substances (EPS) from different Anammox biomass have been extracted and characterized by quantitative and qualitative analysis to investigate its correlation with the enrichment process in a lab scale bioreactor. A decrease of protein to polysaccharide (PN/PS) ratio and an increase in total EPS extraction yield were observed during the enrichment process. The three dimensional excitation emission matrix (3D-EEM) showed similar location of the fluorescence peaks for all samples while samples with Anammox bacteria possess two distinct peaks in the low excitation wavelength range. Multi-excitation peaks may occur as evidenced by the identical fluorescence chromatogram after size exclusion chromatography (SEC) separation at excitation/emission 221/350 nm and 280/330 nm. Ultraviolet (UV) absorbance at 210 nm was recorded simultaneously with fluorescence detection at excitation/emission wavelength 222/300 nm, 221/350 nm and 280/330 nm after separated by SEC. With the enrichment of Anammox bacteria, UV chromatogram showed increase in both intensity and number of peaks, whereas fluorescence chromatograms showed similar peak number and only increase in intensity. An increase of hydrophobicity was observed during the enrichment process. The results of this study are expected to extend the knowledge of EPS evolution of Anammox enrichment process as well as providing novel approach for the characterization of EPS extracted from Anammox sludgeÉlimination de l'azote est obligatoire dans moderne usine de traitement des eaux usées (STEP) en raison de sa toxicité à la fois humaine et l'écosystème. Un niveau élevé d'azote peut provoquer une eutrophisation dans le système aquatique. Élimination de l'azote autotrophes qui combine nitritation partielle et Anammox est une technologie attrayante qui est approprié pour une grande force d'ammonium des eaux usées à faible teneur en carbone organique. Toutefois, le ralentissement de la croissance extrême des bactéries Anammox avec le temps de 9-13 jours doubler entrave la pleine application de l'échelle. L'objectif de cette recherche était d'étudier la faisabilité et la stratégie opérationnelle de l'enrichissement Anammox de boues conventionnelle aérobie (réacteur ASR), la dénitrification des boues (Réacteur DSR) et boue anaérobie (réacteur ANR) en utilisant réacteur biologique séquentiel (SBR). Anammox processus a été établi avec succès en DSR avec une élimination de l'azote total d'environ 80% sous le contrôle strict de l'oxygène au bout de 150 jours, ce qui est confirmé par la composition chimique de l'influent / effluents ainsi que l'analyse microbienne. Sous la même condition opérationnelle, ANR atteint seulement 20-30% d'élimination de l'azote total. Avec un temps plus court de rétention hydraulique (HRT) et de contrôle d'oxygène insuffisante, ASR a atteint 50-60% du total élimination de l'azote après 240 jours. Tous les réacteurs ont connu la fluctuation des performances au cours du processus d'enrichissement, qui est censé être la conséquence de facteurs inhibiteurs tels que l'oxygène dissous, sans nitrites et l'ammoniac libre ainsi que les bactéries coexistantes indésirables qui sont en concurrence pour le même substrat. L'électrophorèse sur gel de gradient dénaturant (DGGE) bande à partir des échantillons d'ADN amplifiés extraites ASR lors de l'étape d'enrichissement différente montre une nette évolution de la composition microbienne. Substances polymères extracellulaires (EPS) de différents biomasse Anammox ont été extraites et caractérisé par analyse quantitative et qualitative pour enquêter sur sa corrélation avec le processus d'enrichissement dans un bioréacteur de l'échelle du laboratoire. Une diminution de la protéine au polysaccharide (PN / PS) rapport et une augmentation du rendement total d'extraction EPS ont été observés au cours du processus d'enrichissement. La matrice à trois dimensions excitation d'émission (3D-EEM) a montré un endroit similaire des pics de fluorescence pour tous les échantillons tandis que les échantillons avec des bactéries Anammox possèdent deux pics distincts dans le bas de gamme d'onde d'excitation. Pics multiples excitation peuvent se produire comme en témoigne la fluorescence identique chromatogramme après chromatographie d'exclusion de taille (SEC) à séparation d'excitation / émission de 221/350 nm et 280/330 nm. Rayons ultraviolets (UV) absorbance à 210 nm a été enregistrée en même temps que la détection de fluorescence à une excitation / émission 222/300 nm de longueur d'onde, 221/350 nm et 280/330 nm après séparées par SEC. Avec l'enrichissement de bactéries Anammox, chromatogramme UV montré une augmentation en intensité et en nombre de pics, alors que chromatogrammes fluorescence ont montré nombre maximal similaire et seulement augmentent en intensité. Une augmentation de l'hydrophobie a été observée au cours du procédé d'enrichissement. Les résultats de cette étude sont attendus pour étendre la connaissance de l'évolution du processus d'enrichissement Anammox EPS ainsi que de fournir nouvelle approche pour la caractérisation des EPS extraites de Anammox boue

New strategies for the wastewater treatment with filtration membranes

A great expansion in the number of full-scale references in wastewater treatment with membranes ocurred in the last two decades. Costs, reference infrastructures, water quality requirements for a further reuse and bibliometric information was collected to assess the current state of based-on-membrane technologies. A compact aerobic approach, combining flocculent and biofilm biomass, treating municipal sewage was proposed. Alternatively, a membrane bioreactor as s polishing step reactors for methanogenic treatments has been also developed. Other approaches were also included, always with a common thread, a filtration membrane

Tratamento de efluentes urbanos e recuperação de energia através de sistema integrado composto por reator anaeróbio, microalgas e wetland construído de fluxo vertical

O presente trabalho teve como objetivo propor um sistema integrado de tratamento de efluentes urbanos composto por reator anaeróbio, microalgas autóctones e wetland construído de fluxo vertical, com macrófita nativa do Sul do Brasil, além de recuperar energia através da biomassa gerada durante o processo. A pesquisa foi desenvolvida junto a estação de tratamento de águas residuais da Universidade de Santa Cruz do Sul (ETE/UNISC). Foi proposto um sistema integrado composto por reator anaeróbico (RA), microalgas (MA) e wetland construído de fluxo vertical (WCFV) para tratamento das águas residuais produzidas no campus da Universidade com tempo total de detenção hidráulica (TDH) de 17 dias. O sistema integrado foi configurado para proliferação de microalgas, a partir de efluente pós-tanque equalizador da ETE e com polimento final através de wetland construído, tendo como partida a configuração do fotobioreator sem inoculação de cepas selvagens ou comerciais de microalgas e com a utilização da espécie de macrófita emergente Hymenachne grumosa no WCFV. Os resultados obtidos demonstraram que o sistema integrado (RA, MA e WCFV) apresenta bom desempenho na redução de COD; DBO5 e Fósforo Total (63,22%; 61,18% e 53,91%, respectivamente), além de taxas de remoção de Nitrogênio Amoniacal (N-NH3); Coliformes totais e Escherichia colide99,98%; 99,99% e 100%, respectivamente. A obtenção das amostras de biomassa algácea para produção de biogás foi realizada através de separação e coleta das microalgas com período de TDH de 14 dias, enquanto a biomassa referente às macrófitas utilizadas no wetland construído foi realizada a cada 6 meses. A conversão da biomassa das microalgas em biogás foi em média de 2322,51NmL-gSV-1com CH4de 54,61% (inverno/2019); de 4491,47 NmL-gSV-1com CH4de 57,17% (primavera/2019 e com geração de biogás de 3826,70NmL-gSV-1 com CH4 de 44,26% para biomassa wetland construído inverno e primavera/2019. Em relação à redução da genotoxicidade, observou-se que o sistema integrado (WCFV) foi eficiente, uma vez que apresentou uma redução significativa (p<0,001) na frequência de micronúcleos (MN) e aberrações cromossômicas (CA) quando comparado com o sistema convencional de tratamento (ETE). Ainda, foi desenvolvido um separador de biomassa microalgal de baixo custo, sem aporte energético com depósito de patente junto ao Instituto Nacional de propriedade Intelectual (INPI). Assim, os resultados do estudo destacam a relevância na proposição do sistema integrado como alternativa de tecnologia sustentável aplicada ao tratamento de águas residuais, uma vez que, além de tratar o efluente de modo eficiente, também demonstrou potencial geração de energia, reforçando o conceito de sustentabilidade no saneamento ambiental.The present work aimed at to propose an integrated system for the treatment of urban wastewaters besides recovering energy through the biomass generated during the process. The system was composed of an anaerobic reactor (AR), autochthonous microalgae (MA) and vertical flow constructed wetlands (VFCW) vegetated with native macrophyte of the South of Brazil with full hydraulic detention time (HDT) of 17 days. The research was carried out at the wastewater treatment plant (WWTP) of the University of Santa Cruz do Sul (ETE/UNISC). The integrated system was configured for MA proliferation, from wastewaters arising from the equalizer tank of WWTP and with final polishing byVFCW, starting with the configuration of the photobioreactor without inoculation of wild or commercial strains of MA and with the use of emerging macrophyte species Hymenachne grumosain VFCW. The results obtained showed that the integrated system (RA, MA and WCFV) reduced COD, BOD5and Total Phosphorus by 63.22%; 61.18% and 53.91%, respectively, besides achieving good removal rates for Ammoniacal Nitrogen (N-NH3) Total coliforms and 99.98% Escherichia coli; 99.99% and 100%, respectively. The collection of algal biomass samples for biogas production was performed by separating and collecting the microalgae with a HDT of 14 days, while the biomass referring to the macrophytes used in the VFCW was carried out every 6 months. The conversion of MA biomass into biogas averaged 2322.51 NmL-gSV-1with 54.61% CH4(winter/2019); 4491.47 NmL-gSV-1with 57.17% CH4(spring/2019) and with biogas generation of 3826.70 NmL-gSV-1with 44.26% CH4for VFCW biomass winter and spring/ 2019. Regarding the reduction of genotoxicity, it was observed that the integrated system was efficient, as it presented a significant reduction (p<0.001) in the frequency of micronuclei (MN) and chromosomal aberrations (CA) when compared to the treatment of the WWTP. Furthermore, a low-cost, energy-free, microalgal biomass separator was developed with a patent deposit at the National Institute of Intellectual Property (INPI). Thus, the results obtained in the present study highlight the relevance of proposing the integrated system as an alternative of sustainable technology applied to the treatment of wastewaters, since, in addition to treating the wastewaters in an efficient manner, it also demonstrated potential for energy generation, reinforcing the concept of sustainability in environmental sanitation

Wastewater Based Microbial Biorefinery for Bioenergy Production

A rapid growth in various industries and domestic activities is resulting in a huge amount of wastewater. Various types of wastewaters, such as textile, municipal, dairy, pharmaceutical, swine, and aquaculture, etc., are produced regularly by respective industries. These wastewaters are rich in nutrient content and promote eutrophication in the ecosystem and pose a threat to flora and fauna. According to an estimate, eutrophication causes losses of almost 2 billion US dollars annually, affecting real estate and fishing activities. Treatment of wastewater is a costly process and recently wastewater treatment with simultaneous energy production has received more attention. Microorganisms can be used to recover nutrients from wastewater and produce bioenergy (biodiesel, biohydrogen, bioelectricity, methane, etc.). A better understanding of the composition of various types of wastewaters and the development of technologies like anaerobic digestion (AD), microbial fuel cell (MFC), and microbial electrolysis cell (MEC) can help to make wastewater-based biorefinery a reality. To provide an overall overview to students, teachers, and researchers on wastewater to bioenergy technology ten chapters are included in this book

Biogas

Anaerobic digestion is by far the most important technology for providing clean renewable energy to millions of people in rural areas around the world. It produces biomethane with anaerobic-digestate as a byproduct that can be used as a biofertilizer. In the context of energy consumption, more than 85% of the total energy consumed currently comes from non-renewable fossil resources. A wide variety of biowastes can be used as feedstocks for biogas production. Biogas technology can provide sustainable, affordable, and eco-friendly green energy along with useful byproducts. This book discusses the basics of biogas production and aims to address the needs of graduate and postgraduate students as well as other professionals through further evaluation of biogas production via case studies