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Christensso M.,AnoxKaldnes AB | Odegaard H.,Norwegian University of Science and Technology
Water Science and Technology | Year: 2011

A hybrid activated sludge/biofilm process was investigated for wastewater treatment in a cold climate region. This process, which contains both suspended biomass and biofilm, usually referred as IFAS process, is created by introducing plastic elements as biofilm carrier media into a conventional activated sludge reactor. In the present study, a hybrid process, composed of an activated sludge and a moving bed biofilm reactor was used. The aim of this paper has been to investigate the performances of a hybrid process, and in particular to gain insight the nitrification process, when operated at relatively low MLSS SRT and low temperatures. The results of a pilot-scale study carried out at the Department of Hydraulic and Environmental Engineering at the Norwegian University of Science and Technology in Trondheim are presented. The experimental campaign was divided into two periods. The pilot plant was first operated with a constant HRT of 4.5 hours, while in the second period the influent flow was increased so that HRT was 3.5 hours. The average temperature was near 11.51C in the overall experimental campaign. The average mixed liquor SRT was 5.7 days. Batch tests on both carriers and suspended biomass were performed in order to evaluate the nitrification rate of the two different biomasses. The results demonstrated that this kind of reactor can efficiently be used for the upgrading of conventional activated sludge plant for achieving year-round nitrification, also in presence of low temperatures, and without the need of additional volumes. © IWA Publishing 2011.


Grant
Agency: European Commission | Branch: FP7 | Program: MC-ITN | Phase: FP7-PEOPLE-2013-ITN | Award Amount: 4.06M | Year: 2013

We will provide the first-ever research training in the transdisciplinary area of Microbial Resource Management and Engineering (MRME) to develop new concepts and technologies to meet the imminent societal challenge of closing the Urban Water Cycle (UWC), the sustainable management of residual waters and the preparation and distribution of safe potable water. The network consists of 10 regional world-leading Network Partners (NP) from private and academic sectors in DK, BE, UK, PT, CH, SE, complemented by 8 associated partners. Transdisciplinary training of 13 ESR and one ER will span from (molecular) microbial ecology to environmental engineering. Each ESR develops a personal and professional development plan. Training elements include expert training through cutting-edge individualized research projects, cross-sectoral mentorships, private sector internships, and participation in Network-wide PhD schools. Schools alternate between professional and technical training. The ITN ends with a fellow-led international research symposium. A supervisory board tracks project implementation. The private sector is engaged at the highest level: 4 private partners are full NPs. The ITN will provide ESRs with transsectoral training and experience, and instill an aptitude for research valorization, to create opportunity for research careers in public and private sectors. This ITN is timely, significant, and unique, as scientific and technological advances create tremendous opportunities for MRME, training in this transdisciplinary area is essentially absent across EU, and the need for innovation in closing the UWC is pressing, as water resources dwindle, urban consumption grows, and existing infrastructure ages. The ITN will structure the European research area and strengthen ties between and within the academic and private partners across regions. Researchers will be trained at the highest level with job prospects across academic, private, and public sectors.


Grant
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: ENV.2010.3.1.1-2 | Award Amount: 4.85M | Year: 2011

The Routes project is addressed to discover new routes in wastewater and sludge treatment which allow: a) to prepare sludge for agricultural utilization by transforming it in a very clean and stabilized product regarding the presence of organic micropollutants (conventional and emerging ones) and of heavy metals, and with respect to hygienic aspects and to phytotoxicity; b) to minimize sludge production by innovative solutions which can be based on different approaches, i.e.: i) metabolic uncoupling where the free energy released by electrons transport is dissipated in heat, in the activation of alternative metabolic routes or in the accumulation of polymeric products, ii) the use of microbial fuel cells, iii) the use of sequencing batch biofilter granular reactor (SBBGR), iiii) the integration of a side-stream process in membrane bioreactors; c) to promote recovery of valuable materials from anaerobic digestion, i.e. biopolymers as polyhydroxyalkanoates and fertilizers; e) to set up and prove at practical scale a novel technique for sludge disposal (wet oxidation) as sustainable alternative to nowadays the most used incineration; f) to minimize energy pumping by adjusting solid concentration, on a practical installation where sludge is pumped from the production site to a centralized plant. The general objective of the Routes proposal is therefore to set up a panel of different solutions to be applied in different conditions and circumstances, strictly following the waste hierarchy of the Directive 08/98 on waste. The above solutions will be studied either in laboratory or at practical scale, depending on the maturity of the technology, in order to provide to the Commission and the technical and scientific community applicable solutions and new routes for sludge management, also based on the best integration between the water and sludge treatment lines.


Albuquerque M.G.E.,New University of Lisbon | Concas S.,New University of Lisbon | Bengtsson S.,AnoxKaldnes AB | Reis M.A.M.,New University of Lisbon
Bioresource Technology | Year: 2010

Polyhydroxyalkanoates (PHAs) are promising biodegradable polymers. The use of mixed microbial cultures (MMC) and low cost feedstocks have a positive impact on the cost-effectiveness of the process. It has typically been carried out in Sequencing Batch Reactors (SBR). In this study, a 2-stage CSTR system (under Feast and Famine conditions) was used to effectively select for PHA-storing organisms using fermented molasses as feedstock. The effect of influent substrate concentration (60-120 Cmmol VFA/L) and HRT ratio between the reactors (0.2-0.5 h/h) on the system's selection efficiency was assessed. It was shown that Feast reactor residual substrate concentration impacted on the selective pressure for PHA storage (due to substrate-dependent kinetic limitation). Moreover, a residual substrate concentration coming from the Feast to the Famine reactor did not jeopardize the physiological adaptation required for enhanced PHA storage. The culture reached a maximum PHA content of 61%. This success opens new perspectives to the use of wastewater treatment infrastructure for PHA production, thus valorizing either excess sludge or wastewaters. © 2010 Elsevier Ltd. All rights reserved.


Bengtsson S.,AnoxKaldnes AB | Pisco A.R.,REQUIMTE | Reis M.A.M.,REQUIMTE | Lemos P.C.,REQUIMTE
Journal of Biotechnology | Year: 2010

Batch production of polyhydroxyalkanoates (PHAs) under aerobic conditions by an open mixed culture enriched in glycogen accumulating organisms (GAOs) with fermented sugar cane molasses as substrate was studied. The produced polymers contained five types of monomers, namely 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), 3-hydroxy-2-methylbutyrate (3H2MB), 3-hydroxy-2-methylvalerate (3H2MV) and the medium chain length monomer 3-hydroxyhexanoate (3HHx). With fermented molasses as substrate, PHA was produced under concurrent consumption of stored glycogen with yields of 0.47-0.66 C-mol PHA per C-mol of total carbon substrate and with rates up to 0.65 C-mol/C-mol X h. In order to investigate the role of glycogen during aerobic PHA accumulation in GAOs, synthetic single volatile fatty acids (VFAs) were used as substrates and it was found that the fate of glycogen was dependent on the type of VFA being consumed. Aerobic PHA accumulation occurred under concurrent glycogen consumption with acetate as substrate and under minor concurrent glycogen production with propionate as substrate. With butyrate and valerate as substrates, PHA accumulation occurred with the glycogen pool unaffected. The composition of the PHA was dependent on the VFA composition of the fermented molasses and was 56-70 mol-% 3HB, 13-43 mol-% 3HV, 1-23 mol-% 3HHx and 0-2 mol-% 3H2MB and 3H2MV. The high polymer yields and production rates suggest that enrichment of GAOs can be a fruitful strategy for mixed culture production of PHA from waste substrates. © 2009 Elsevier B.V. All rights reserved.


Bengtsson S.,AnoxKaldnes AB | Pisco A.R.,New University of Lisbon | Johansson P.,AnoxKaldnes AB | Lemos P.C.,New University of Lisbon | Reis M.A.M.,New University of Lisbon
Journal of Biotechnology | Year: 2010

Polyhydroxyalkanoates (PHAs) produced from fermented molasses and synthetic feeds containing single volatile fatty acids (VFAs) by an open mixed culture enriched in glycogen accumulating organisms (GAOs) were characterized with regards to molecular weight and thermal properties. The polymer contained five types of monomers, namely 3-hydroxybutyrate, 3-hydroxy-2-methylbutyrate, 3-hydroxyvalerate, 3-hydroxy-2-methylvalerate and 3-hydroxyhexanoate in different ratios depending on the VFA composition of the substrate. Polymers produced from fermented molasses had weight average molecular weights (M w) in the range (3.5-4.3)×10 5g/mol and polydispersity indexes (PDI) of 1.8-2.1 while polymers produced from synthetic VFAs had M w of (4.5-9.0)×10 5g/mol and PDI of 1.7-3.9. Thermal properties such as glass transition temperature (-14°C to 4.8°C), melting temperature (89-174°C) and melting enthalpy (0-82.1J/g) were controlled in broad ranges by the monomer composition. The decomposition temperatures of the polymers produced were between 277.2°C and 294.9°C, and independent of monomer composition and molecular weight. © 2010 Elsevier B.V.


Nikodinovic-Runic J.,University of Belgrade | Guzik M.,Bioplastech | Kenny S.T.,Bioplastech | Babu R.,Trinity College Dublin | And 2 more authors.
Advances in Applied Microbiology | Year: 2013

Research into the production of biodegradable polymers has been driven by vision for the most part from changes in policy, in Europe and America. These policies have their origins in the Brundtland Report of 1987, which provides a platform for a more sustainable society. Biodegradable polymers are part of the emerging portfolio of renewable raw materials seeking to deliver environmental, social, and economic benefits. Polyhydroxyalkanoates (PHAs) are naturally-occurring biodegradable-polyesters accumulated by bacteria usually in response to inorganic nutrient limitation in the presence of excess carbon. Most of the early research into PHA accumulation and technology development for industrial-scale production was undertaken using virgin starting materials. For example, polyhydroxybutyrate and copolymers such as polyhydroxybutyrate-co-valerate are produced today at industrial scale from corn-derived glucose. However, in recent years, research has been undertaken to convert domestic and industrial wastes to PHA. These wastes in today's context are residuals seen by a growing body of stakeholders as platform resources for a biobased society. In the present review, we consider residuals from food, plastic, forest and lignocellulosic, and biodiesel manufacturing (glycerol). Thus, this review seeks to gain perspective of opportunities from literature reporting the production of PHA from carbon-rich residuals as feedstocks. A discussion on approaches and context for PHA production with reference to pure- and mixed-culture technologies is provided. Literature reports advocate results of the promise of waste conversion to PHA. However, the vast majority of studies on waste to PHA is at laboratory scale. The questions of surmounting the technical and political hurdles to industrialization are generally left unanswered. There are a limited number of studies that have progressed into fermentors and a dearth of pilot-scale demonstration. A number of fermentation studies show that biomass and PHA productivity can be increased, and sometimes dramatically, in a fermentor. The relevant application-specific properties of the polymers from the wastes studied and the effect of altered-waste composition on polymer properties are generally not well reported and would greatly benefit the progress of the research as high productivity is of limited value without the context of requisite case-specific polymer properties. The proposed use of a waste residual is advantageous from a life cycle viewpoint as it removes the direct or indirect effect of PHA production on land usage and food production. However, the question, of how economic drivers will promote or hinder advancements to demonstration scale, when wastes generally become understood as resources for a biobased society, hangs today in the balance due to a lack of shared vision and the legacy of mistakes made with first generation bioproducts. © 2013 Elsevier Inc.


Morgan-Sagastume F.,AnoxKaldnes AB | Pratt S.,University of Queensland | Karlsson A.,AnoxKaldnes AB | Cirne D.,University of Queensland | And 2 more authors.
Bioresource Technology | Year: 2011

This work focuses on fermentation of pre-treated waste activated sludge (WAS) to generate volatile fatty acids (VFAs). Pre-treatment by high-pressure thermal hydrolysis (HPTH) was shown to aid WAS fermentation. Compared to fermentation of raw WAS, pre-treatment enabled a 2-5x increase in VFA yield (gVFACODgTCOD-1) and 4-6x increase in VFA production rate (gVFACODL-1d-1). Three sludges, pre-treated in full-scale HPTH plants, were fermented. One was from a plant processing a mix of primary sludge and WAS and the other two from plants processing solely WAS. The HPTH plants solubilised suspended matter, evidenced by a 20-30% decrease in suspended solids and an increase of soluble COD: total COD from 0.04 to 0.4. Fermentation of the three sludges yielded similar VFA concentrations (15-20gVFACODL-1). The yields were largely independent of retention time (1d-6d) and temperature (42°C, 55°C). Also, the product spectrum depended mostly on the composition of the sludge rather than on operating conditions. © 2010 Elsevier Ltd.


Di Trapani D.,University of Palermo | Christensson M.,AnoxKaldnes AB | Torregrossa M.,University of Palermo | Viviani G.,University of Palermo | Odegaard H.,Norwegian University of Science and Technology
Biochemical Engineering Journal | Year: 2013

The main aim of the study was to investigate a hybrid MBBR process, mostly in terms of organic matter removal and nitrification, when operating with different values of the mixed liquor sludge retention time (SRT), and highlighting the influence of temperature on the process. Based on experience in practice it was hypothesized that nitrification could be maintained at far lower SRT's than in conventional activated sludge systems and with high organic loading rates applied. A field gathering campaign has been carried out on a hybrid activated sludge/biofilm. The obtained results highlighted that the pilot plant was capable to remove the organic matter at loading rates up to 3.00kgTCODm-3day-1, also showing very high nitrification activity. Ammonia uptake rate (AUR) batch test showed that biofilm nitrification activity increased when the mixed liquor SRT decreased. The final suggestion is that it is possible to run a hybrid reactor with low mixed liquor SRT values, as well as low temperatures, still having a high ammonium removal efficiency, since a large fraction of nitrification activity will take place in the biofilm. © 2013 Elsevier B.V.


Carlsson M.,Lulea University of Technology | Carlsson M.,AnoxKaldnes AB | Lagerkvist A.,Lulea University of Technology | Morgan-Sagastume F.,AnoxKaldnes AB
Waste Management | Year: 2012

Focus is placed on substrate pre-treatment in anaerobic digestion (AD) as a means of increasing biogas yields using today's diversified substrate sources. Current pre-treatment methods to improve AD are being examined with regard to their effects on different substrate types, highlighting approaches and associated challenges in evaluating substrate pre-treatment in AD systems and its influence on the overall system of evaluation. WWTP residues represent the substrate type that is most frequently assessed in pre-treatment studies, followed by energy crops/harvesting residues, organic fraction of municipal solid waste, organic waste from food industry and manure. The pre-treatment effects are complex and generally linked to substrate characteristics and pre-treatment mechanisms. Overall, substrates containing lignin or bacterial cells appear to be the most amendable to pre-treatment for enhancing AD. Approaches used to evaluate AD enhancement in different systems is further reviewed and challenges and opportunities for improved evaluations are identified. © 2012 Elsevier Ltd.

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