Assessing energy benefits of operating anaerobic digesters at low temperature with solids pre‐ozonation

Further to the Kyoto Protocol, many European countries have introduced investment subsidies for the development of anaerobic digestion and biogas technologies. These subsidies (up to 40% of project costs) supported the installation of hundreds of biogas plants in Europe over the last 3-4 years (Grim et al., 2015). Anaerobic digestion is an effective means of reducing waste biosolids from activated sludge wastewater treatment, the handling and disposal of which can reach up to 60% of the operational cost of a treatment plant (Liu, 2003). The objective of the current research is develop new anaerobic digestion processes that can further reduce biosolids and enhance energy production. Conventionally, anaerobic digesters are operated at 35 ºC or higher temperatures in order to overcome the rate-limiting step of hydrolysis. However, the energy expenditure for heating anaerobic digesters may be high in northern countries like Canada where the treatment process temperature remains below 12 ºC for 4-6 months per year. In a recent laboratory study, we have shown that it was possible to operate batch anaerobic digesters at 20 ºC by synergistically combining them with ozonation of waste activated sludge (WAS) solids. The integration of solids ozonation and anaerobic digestion at 20 ºC resulted in a volatile suspended solids (VSS) destruction of 67%, while conventional anaerobic digestion at 35 ºC only achieved a 47% destruction. The solids loadings and hydraulic retention times (HRT) were the same for both digesters, but the solids retention time (SRT) was 20 days (same as the HRT) in the conventional digester and 27 days for the ozonated digester to maintain similar steady-state VSS concentrations. The increase in VSS destruction enhanced methane production from 53.1 mL methane/g VSSin for the 35 ºC-conventional digester to 69.2 mL methane/g VSSin for the 20 ºC-ozonated digester, a 30% increase. The energy expenditures of anaerobic digesters operated at 35 ºC, and at 20 ºC with solids ozonation were characterized from literature values to determine the energy sustainability of these operational scenarios (Ruggeri et al., 2015). The benchmark digester considered received 1,000 m3/d of WAS at 3% total solids (TS) and 10 ºC (Figure 1). The modeling considered heat losses from the digester, the heat transfer efficiency between influent and effluent (70%), the biogas conversion into electricity to mix the digesters and produce ozone (35% energy conversion), and solids thickening. Calculations found the 20 ºC-ozonated digester to produce 20% more energy than the 35 ºC-conventional digester (net energy balance: +147 GJ/day and +129 GJ/d, respectively). Assuming operation of the ozonated digester at 10 ºC with similar performance, the increase in net energy production over the conventional reactor reached 32% (+170 GJ/d). The results demonstrate that higher energy gains can be achieved with anaerobic digestion at low temperature by combining it with WAS ozonation. As both scenarios had an Energy Sustainability Index (ESI = energy produced/ direct energy; the energy necessary to run the process, namely electricity and heat) (Ruggeri et al., 2015) above 1, they can be judged potentially energy sustainable. However, the higher energy returns and VSS destruction of the 20 ºC-ozonated digester suggest energy efficacy and economic gains for this approach. Please click Additional Files below to see the full abstract

SEN (Special Educational Needs) and inclusion in a time of "famine"

This thesis is about the changes a particular LEA implemented to funding for pupils with Statements of SEN in the light of a funding crisis affecting the whole LEA in 2003. It disproves the case that the Authority was making and which was even being made in academic literature, that SEN funding was imminently out of control. Instead it shows the deep-seated effect of neoliberalism on special education. It also argues that the Authority’s call for greater inclusion was used rhetorically to justify the funding changes and that inclusion became a means to move pupils with Statements who were educated outside the Authority back into schools within the Authority. It shows that changes in funding Statements marked a change in emphasis regarding decision-making about writing Statements – considerations about funding became more important than considerations about the best educational interests of the child. Finally, it argues that funding pupils with Statements was politically determined, not mainly financially driven, and that such funding became dependent on the number of pupils with Free School Meals and other indications of ‘deprivation’, rather than being based on the actual number of pupils with Statements per se. This, it argues, caused conflict amongst schools and, crucially, also calls into question how SEN and inclusion are themselves defined. This thesis is relevant to present debates about special education because the Coalition government is developing a new SEN Code of Practice and is implementing changes using similar arguments to those discussed in the thesis – the present government is claiming that there is a funding crisis, that ‘proxy measures’ should be used to count the incidence of SEN and that the ‘bias’ toward inclusion should be removed. Key words/phrases: SEN, Inclusion, Statements of SEN, Local Authority education funding crisis, ‘proxy indicators’ for SEN, SEN Time Bomb, Funding for inclusion, funding for special education, political economy of special education, neoliberalism, local democrac

Water and sanitation: an essential battlefront in the war on antimicrobial resistance

Water and sanitation represent a key battlefront in combatting the spread of antimicrobial resistance (AMR). Basic water sanitation infrastructure is an essential first step towards protecting public health, thereby limiting the spread of pathogens and the need for antibiotics. AMR presents unique human health risks, meriting new risk assessment frameworks specifically adapted to water and sanitation-borne AMR. There are numerous exposure routes to AMR originating from human waste, each of which must be quantified for its relative risk to human health. Wastewater treatment plants play a vital role in centralized collection and treatment of human sewage, but there are numerous unresolved issues in terms of the microbial ecological processes occurring within them and the extent to which they attenuate or amplify AMR. Research is needed to advance understanding of the fate of resistant bacteria and antibiotic resistance genes in various waste management systems, depending on the local constraints and intended reuse applications. World Health Organization and national AMR action plans would benefit from a more holistic 'One Water' understanding. In this article we provide a framework for research, policy, practice and public engagement aimed at limiting the spread of AMR from water and sanitation in low-, medium- and high-income countries

An Environmental Science and Engineering Framework for Combating Antimicrobial Resistance

On June 20, 2017, members of the environmental engineering and science (EES) community convened at the Association of Environmental Engineering and Science Professors (AEESP) Biennial Conference for a workshop on antimicrobial resistance. With over 80 registered participants, discussion groups focused on the following topics: risk assessment, monitoring, wastewater treatment, agricultural systems, and synergies. In this study, we summarize the consensus among the workshop participants regarding the role of the EES community in understanding and mitigating the spread of antibiotic resistance via environmental pathways. Environmental scientists and engineers offer a unique and interdisciplinary perspective and expertise needed for engaging with other disciplines such as medicine, agriculture, and public health to effectively address important knowledge gaps with respect to the linkages between human activities, impacts to the environment, and human health risks. Recommendations that propose priorities for research within the EES community, as well as areas where interdisciplinary perspectives are needed, are highlighted. In particular, risk modeling and assessment, monitoring, and mass balance modeling can aid in the identification of “hot spots” for antibiotic resistance evolution and dissemination, and can help identify effective targets for mitigation. Such information will be essential for the development of an informed and effective policy aimed at preserving and protecting the efficacy of antibiotics for future generations

MiDAS 4: A global catalogue of full-length 16S rRNA gene sequences and taxonomy for studies of bacterial communities in wastewater treatment plants

Microbial communities are responsible for biological wastewater treatment, but our knowledge of their diversity and function is still poor. Here, we sequence more than 5 million high-quality, full-length 16S rRNA gene sequences from 740 wastewater treatment plants (WWTPs) across the world and use the sequences to construct the ‘MiDAS 4’ database. MiDAS 4 is an amplicon sequence variant resolved, full-length 16S rRNA gene reference database with a comprehensive taxonomy from domain to species level for all sequences. We use an independent dataset (269 WWTPs) to show that MiDAS 4, compared to commonly used universal reference databases, provides a better coverage for WWTP bacteria and an improved rate of genus and species level classification. Taking advantage of MiDAS 4, we carry out an amplicon-based, global-scale microbial community profiling of activated sludge plants using two common sets of primers targeting regions of the 16S rRNA gene, revealing how environmental conditions and biogeography shape the activated sludge microbiota. We also identify core and conditionally rare or abundant taxa, encompassing 966 genera and 1530 species that represent approximately 80% and 50% of the accumulated read abundance, respectively. Finally, we show that for well-studied functional guilds, such as nitrifiers or polyphosphate-accumulating organisms, the same genera are prevalent worldwide, with only a few abundant species in each genus.Fil: Dueholm, Morten Kam Dahl. Aalborg University; DinamarcaFil: Nierychlo, Marta. Aalborg University; DinamarcaFil: Andersen, Kasper Skytte. Aalborg University; DinamarcaFil: Rudkjøbing, Vibeke. Aalborg University; DinamarcaFil: Knutsson, Simon. Aalborg University; DinamarcaFil: Arriaga, Sonia. Instituto Potosino de Investigación Científica y Tecnológica; MéxicoFil: Bakke, Rune. University College of Southeast Norway; NoruegaFil: Boon, Nico. University of Ghent; BélgicaFil: Bux, Faizal. Durban University of Technology; SudáfricaFil: Christensson, Magnus. Veolia Water Technologies Ab; SueciaFil: Chua, Adeline Seak May. University Malaya; MalasiaFil: Curtis, Thomas P.. University of Newcastle; Reino UnidoFil: Cytryn, Eddie. Agricultural Research Organization Of Israel; IsraelFil: Erijman, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. Universidad de Buenos Aires; ArgentinaFil: Etchebehere, Claudia. Instituto de Investigaciones Biológicas "Clemente Estable"; UruguayFil: Fatta Kassinos, Despo. University of Cyprus; ChipreFil: Frigon, Dominic. McGill University; CanadáFil: Garcia Chaves, Maria Carolina. Universidad de Antioquia; ColombiaFil: Gu, April Z.. Cornell University; Estados UnidosFil: Horn, Harald. Karlsruher Institut Für Technologie; AlemaniaFil: Jenkins, David. David Jenkins & Associates Inc; Estados UnidosFil: Kreuzinger, Norbert. Tu Wien; AustriaFil: Kumari, Sheena. Durban University of Technology; SudáfricaFil: Lanham, Ana. University of Bath; Reino UnidoFil: Law, Yingyu. Singapore Centre For Environmental Life Sciences Engineering; SingapurFil: Leiknes, TorOve. King Abdullah University of Science and Technology; Arabia SauditaFil: Morgenroth, Eberhard. Eth Zürich; SuizaFil: Muszyński, Adam. Politechnika Warszawska; PoloniaFil: Petrovski, Steve. La Trobe University; AustraliaFil: Pijuan, Maite. Catalan Institute For Water Research; EspañaFil: Pillai, Suraj Babu. Va Tech Wabag Ltd; IndiaFil: Reis, Maria A. M.. Universidade Nova de Lisboa; PortugalFil: Rong, Qi. Chinese Academy of Sciences; ChinaFil: Rossetti, Simona. Istituto Di Ricerca Sulle Acque (irsa) ; Consiglio Nazionale Delle Ricerche;Fil: Seviour, Robert. La Trobe University; AustraliaFil: Tooker, Nick. University of Massachussets; Estados UnidosFil: Vainio, Pirjo. Espoo R&D Center; FinlandiaFil: van Loosdrecht, Mark. Delft University of Technology; Países BajosFil: Vikraman, R.. VA Tech Wabag, Philippines Inc; FilipinasFil: Wanner, Jiří. University of Chemistry And Technology; República ChecaFil: Weissbrodt, David. Delft University of Technology; Países BajosFil: Wen, Xianghua. Tsinghua University; ChinaFil: Zhang, Tong. The University of Hong Kong; Hong KongFil: Nielsen, Per H.. Aalborg University; DinamarcaFil: Albertsen, Mads. Aalborg University; DinamarcaFil: Nielsen, Per Halkjær. Aalborg University; Dinamarc

An Environmental Science and Engineering Framework for Combating Antimicrobial Resistance

On June 20, 2017, members of the environmental engineering and science (EES) community convened at the Association of Environmental Engineering and Science Professors (AEESP) Biennial Conference for a workshop on antimicrobial resistance. With over 80 registered participants, discussion groups focused on the following topics: risk assessment, monitoring, wastewater treatment, agricultural systems, and synergies. In this study, we summarize the consensus among the workshop participants regarding the role of the EES community in understanding and mitigating the spread of antibiotic resistance via environmental pathways. Environmental scientists and engineers offer a unique and interdisciplinary perspective and expertise needed for engaging with other disciplines such as medicine, agriculture, and public health to effectively address important knowledge gaps with respect to the linkages between human activities, impacts to the environment, and human health risks. Recommendations that propose priorities for research within the EES community, as well as areas where interdisciplinary perspectives are needed, are highlighted. In particular, risk modeling and assessment, monitoring, and mass balance modeling can aid in the identification of 'hot spots' for antibiotic resistance evolution and dissemination, and can help identify effective targets for mitigation. Such information will be essential for the development of an informed and effective policy aimed at preserving and protecting the efficacy of antibiotics for future generations

Proposed Mechanism Explaining Seasonal Biological Foaming in Activated Sludge Systems; Foam-Causing Bacteria Specialize in Consuming Lipids

239 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2005.The validity of this mechanism was first tested by studying the relationship between lipase (lipid hydrolyzing enzyme) activity, temperature, and foam occurrences. Lipase activity was found to be higher in foaming plants and very sensitive to temperature, substantiating the role of temperature in seasonal biological foaming. The validity of the assumption that the mycolata specialize in consuming lipids, which are slowly degradable substrates, was also tested. To this end, a model capable the predicting the dynamics of the cellular rRNA pool was developed and validated. This model predicted that the diurnal rRNA profile of a population consuming slowly degradable substrates remains stable throughout the day. Conversely, the diurnal rRNA profile of a population consuming readily degradable substrates varies due to variations in COD loading rates. Thus, the modeling exercise linked the molecular identification of microbial populations and the determination of their ecological function. Diurnal rRNA profiles were then measured for bacterial populations found in full-scale activated sludge wastewater treatment plants, and the experiment support the assumption that mycolata specialize in consuming lipids.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Molecular and phenotypic characterization of the microbial communities in two pulp and paper wastewater treatment systems

Phylogenetic hybridization and phenotypic fingerprinting were applied to the analysis of bacterial communities in wastewater treatment systems. These approaches were aimed at (i) developing monitoring tools able to foresee operational problems, and (ii) providing the rationale to optimize the operation of bioreactors. The work presented is intended to first describe the community found in two reactors treating pulp and paper mill effluent, and second evaluate the possibilities of these techniques with respect to the development of new monitoring tools.Phylogenetic membrane hybridization showed that the bacterial communities were dominated by Alpha and Beta Proteobacteria, a structure probably linked to the low F:M ratio. Other important factors determining the community structure were the proportion of COD in the high molecular weight fraction, the sludge age, phosphate addition, and the concentration of specific compounds (alcohols, phenols, volatile fatty acids) in the influent. The community structure partly determined the sludge characteristics demonstrating its potential value in the assessment of reactor performance. The results obtained by phylogenetic membrane hybridization suggest that the probes used in a monitoring tool would not need to be targeted to the species level to provide relevant information. However, they also suggest that the technique is more sensitive to changes in population density as opposed to changes in bacterial metabolism.Phenotypic fingerprinting measured a smaller difference between the communities of the two reactors studied than what was measured by phylogenetic membrane hybridization. However, differences in heterotrophic activities observed between the two communities were linked to differences in influent composition

Genome-scale metabolic model of Rhodococcus jostii RHA1 (iMT1174) to study the accumulation of storage compounds during nitrogen-limited condition

Rhodococcus jostii RHA1 growing on different substrates is capable of accumulating simultaneously three types of carbon storage compounds: glycogen, polyhydroxyalkanoates (PHA), and triacylglycerols (TAG). Under nitrogen-limited (N-limited) condition, the level of storage increases as is commonly observed for other bacteria. The proportion of each storage compound changes with substrate, but it remains unclear what modelling approach should be adopted to predict the relative composition of the mixture of the storage compounds. We analyzed the growth of R. jostii RHA1 under N-limited conditions using a genome-scale metabolic modelling approach to determine which global metabolic objective function could be used for the prediction