Rapid removal of ammonium from domestic wastewater using polymer hydrogels

To date, technologies to recover ammonium from domestic wastewater from the mainstream have not found widespread application. This is largely due to the low ammonium concentrations in these wastewater streams. This paper reports on the use of polymer hydrogels for rapid sorption of ammonium from domestic wastewater coupled with efficient regeneration by mild acid washing. The sorption capacity of the hydrogel was 8.8-32.2 mg NH4-N/g, which corresponds to removal efficiencies ranging from 68% to 80% NH4-N, increasing proportionally with the initial ammonium concentration. It was, however, unaffected by changes in pH, as the sorption capacity remained constant from pH 5.0-8.0. Importantly, effective regeneration of the hydrogels under mildly acidic conditions (i.e. pH 4.0) was demonstrated with minimal loss in sorption performance following multiple sorption/desorption cycles. Overall, this study highlights the potential of low-cost polymer hydrogels for achieving mainstream ammonium recovery from domestic wastewater

Autotrophic nitrogen assimilation and carbon capture for microbial protein production by a novel enrichment of hydrogen-oxidizing bacteria

Domestic used water treatment systems are currently predominantly based on conventional resource inefficient treatment processes. While resource recovery is gaining momentum it lacks high value end-products which can be efficiently marketed. Microbial protein production offers a valid and promising alternative by upgrading low value recovered resources into high quality feed and also food. In the present study, we evaluated the potential of hydrogen-oxidizing bacteria to upgrade ammonium and carbon dioxide under autotrophic growth conditions. The enrichment of a generic microbial community and the implementation of different culture conditions (sequenced batch resp. continuous reactor) revealed surprising features. At low selection pressure (i.e. under sequenced batch culture at high solid retention time), a very diverse microbiome with an important presence of predatory Bdellovibrio spp. was observed. The microbial culture which evolved under high rate selection pressure (i.e. dilution rate D = 0.1 h) under continuous reactor conditions was dominated by Sulfuricurvum spp. and a highly stable and efficient process in terms of N and C uptake, biomass yield and volumetric productivity was attained. Under continuous culture conditions the maximum yield obtained was 0.29 g cell dry weight per gram chemical oxygen demand equivalent of hydrogen, whereas the maximum volumetric loading rate peaked 0.41 g cell dry weight per litre per hour at a protein content of 71%. Finally, the microbial protein produced was of high nutritive quality in terms of essential amino acids content and can be a suitable substitute for conventional feed sources such as fishmeal or soybean meal

Carbon emission avoidance and capture by producing in-reactor microbial biomass based food, feed and slow release fertilizer : potentials and limitations

Jo De Vrieze is supported as postdoctoral fellow from the Research Foundation Flanders (FWO-Vlaanderen). IP, KR and WV acknowledge support from the Australian Research Council (ARC), project DP170102812. KR acknowledges support from the Research Foundation Flanders (FWO-Vlaanderen), project G018814N and Interreg project EnOP. The input from PS contributed to the following projects: DEVIL [NE/M021327/1], MAGLUE [EP/M013200/1], U-GRASS [NE/M016900/1], Assess-BECCS [funded by UKERC] and Soils-R-GRREAT [NE/P019455/1].Peer reviewedPostprin

How can we possibly resolve the planet’s nitrogen dilemma?

Peer reviewe

Articulating the effect of food systems innovation on the Sustainable Development Goals

Food system innovations will be instrumental to achieving multiple Sustainable Development Goals (SDGs). However, major innovation breakthroughs can trigger profound and disruptive changes, leading to simultaneous and interlinked reconfigurations of multiple parts of the global food system. The emergence of new technologies or social solutions, therefore, have very different impact profiles, with favourable consequences for some SDGs and unintended adverse side-effects for others. Stand-alone innovations seldom achieve positive outcomes over multiple sustainability dimensions. Instead, they should be embedded as part of systemic changes that facilitate the implementation of the SDGs. Emerging trade-offs need to be intentionally addressed to achieve true sustainability, particularly those involving social aspects like inequality in its many forms, social justice, and strong institutions, which remain challenging. Trade-offs with undesirable consequences are manageable through the development of well planned transition pathways, careful monitoring of key indicators, and through the implementation of transparent science targets at the local level

Articulating the effect of food systems innovation on the Sustainable Development Goals

Food system innovations will be instrumental to achieving multiple Sustainable Development Goals (SDGs). However, major innovation breakthroughs can trigger profound and disruptive changes, leading to simultaneous and interlinked reconfigurations of multiple parts of the global food system. The emergence of new technologies or social solutions, therefore, have very different impact profiles, with favourable consequences for some SDGs and unintended adverse side-effects for others. Stand-alone innovations seldom achieve positive outcomes over multiple sustainability dimensions. Instead, they should be embedded as part of systemic changes that facilitate the implementation of the SDGs. Emerging trade-offs need to be intentionally addressed to achieve true sustainability, particularly those involving social aspects like inequality in its many forms, social justice, and strong institutions, which remain challenging. Trade-offs with undesirable consequences are manageable through the development of well planned transition pathways, careful monitoring of key indicators, and through the implementation of transparent science targets at the local level

Articulating the effect of food systems innovation on the Sustainable Development Goals

Acknowledgments MH, DM-D, JP, JRB, AH, GDB, CMG, CLM, and KR acknowledge funding from the Commonwealth Scientific and Industrial Research Organisation. PKT, BMC, AJ, and AML acknowledge funding from the CGIAR Research Program on Climate Change, Agriculture and Food Security, which is supported by the CGIAR Trust Fund and through bilateral funding agreements. PP acknowledges funding from the German Federal Ministry of Education and Research for the BIOCLIMAPATHS project.Peer reviewedPublisher PD

Electrochemical sulfide abatement in sewer systems

Hydrogen sulfide generation in sewer networks represents a major issue in sewer management. It causes sewer corrosion, results in odour problems and its toxicity can cause health problems for sewer workers. Especially sewer corrosion is of concern as it causes severe damage to the sewer infrastructure. For example, the costs associated with sewer corrosion are in the order of $100 million dollar annually in Australia alone (private communication with Water Services Association of Australia). Existing strategies to prevent sewer corrosion are considered expensive as they normally involve the continuous dosing (i.e. 24 hours a day and 7 days a week) of significant amounts of chemicals. In view of the practical limitations of existing strategies there is an urgent need for alternative sulfide abatement strategies. Recent advances in electrode development and operation have stimulated an interest in electrochemical techniques for the remediation of sulfide from wastewater. Electrochemical techniques offer several advantages over existing technologies as they do not require dosing, transport and storage of hazardous chemicals, all of which constitute serious occupational health and safety hazards. Therefore, this thesis aimed to develop and demonstrate the working principle of a novel technology using an electrochemical cell for sulfide abatement in sewer systems. Several electrochemical approaches, either based on anodic reactions (i.e. direct and indirect sulfide oxidation by in-situ generated oxygen) or cathodic reactions (i.e. hydrogen peroxide or caustic generation), were investigated. At the anode side, it was established that direct oxidation of sulfide was not feasible, due to the low sulfide concentrations normally present in sewage. The results also showed that independent of the electrode materials used, namely, Ta/Ir, Ru/Ir, Pt/Ir, PbO2 and SnO2 coated titanium, oxidation occurred mainly indirectly via electrogenerated oxygen. Furthermore, elevated chloride concentrations, often observed in coastal areas, did not entail any significant difference in performance. The long-term performance of electrochemical sulfide removal under real sewer conditions was investigated during field trials. Sulfide could be removed to concentrations below 1 mg L-1 at average sulfide removal efficiencies above 80$2.5-9.4 kg S-1 to AUS $0.83-1.17 kg S-1. The results obtained in this thesis clearly show the economic potential of in-situ generation of caustic from sewage. However, to get to a mature technology at full scale, several process and engineering aspects have to be solved. In addition, the long-term performance at larger scale under real sewer conditions is needed to validate the most important process parameters in order to accurately assess the costs of this promising technique

Measuring development of environmental awareness and moral reasoning: a case-study of a civil engineering course

Environmental awareness and ethical moral reasoning are important aspects of the engineering profession. Yet, engineering programmes have been struggling to teach these topics and measure the effectiveness of these educational interventions. In this study, we tested the effectiveness of two independent measures of environmental awareness and moral reasoning. We conducted pre-and post-test in two groups (experimental and control). Our sample was 84 students in the control group and 152 students in the experimental group. Data were collected with a survey. Results suggest the instruments were effective in measuring changes in scores, although they presented some limitations. Based on our results, we discuss implications for education practice and policy

Microbial protein: future sustainable food supply route with low environmental footprint

Microbial biotechnology has a long history of producing feeds and foods. The key feature of today's market economy is that protein production by conventional agriculture based food supply chains is becoming a major issue in terms of global environmental pollution such as diffuse nutrient and greenhouse gas emissions, land use and water footprint. Time has come to re-assess the current potentials of producing protein-rich feed or food additives in the form of algae, yeasts, fungi and plain bacterial cellular biomass, producible with a lower environmental footprint compared with other plant or animal-based alternatives. A major driver is the need to no longer disintegrate but rather upgrade a variety of low-value organic and inorganic side streams in our current non-cyclic economy. In this context, microbial bioconversions of such valuable matters to nutritive microbial cells and cell components are a powerful asset. The worldwide market of animal protein is of the order of several hundred million tons per year, that of plant protein several billion tons of protein per year; hence, the expansion of the production of microbial protein does not pose disruptive challenges towards the process of the latter. Besides protein as nutritive compounds, also other cellular components such as lipids (single cell oil), polyhydroxybuthyrate, exopolymeric saccharides, carotenoids, ectorines, (pro)vitamins and essential amino acids can be of value for the growing domain of novel nutrition. In order for microbial protein as feed or food to become a major and sustainable alternative, addressing the challenges of creating awareness and achieving public and broader regulatory acceptance are real and need to be addressed with care and expedience