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

Ergonomics in control room design

Ergonomic contributions in early design phases of large-scale projects are not yet common practice. In this paper a description is given of a control room design project, in which ergonomists participated from the very beginning. First, the scope of the project and a methodical approach to the design are introduced. This is followed by an overview of the activities of ergonomists in this particular project. The second part of this paper concerns the experiences with this methodical approach and design practice. These are discussed by the former control room project manager, one of the ergonomists, the interior architect and a user representative. It is concluded that it is possible to include ergonomics as well as user participation in every design phase without getting behind on time schedules and keeping within available budgets. A lot of useful design and engineering data could be derived from the situation analysis in the existing situation and the full-scale mock-up evaluation that was carried out. Besides workplace design, job design (operator workload) and work organization design were essential to the success of the project

Diet, faecal pH and colorectal cancer.

We suggest that a lower faecal pH may be correlated with a lower mortality of large-bowel cancer and that faecal pH should always be considered in epidemiological studies on the role of diet in colon carcinogenesis

Rapid Assessment of Floating Macroplastic Transport in the Rhine

Most marine litter pollution is assumed to originate from land-based sources, entering the marine environment through rivers. To better understand and quantify the risk that plastic pollution poses on aquatic ecosystems, and to develop effective prevention and mitigation methods, a better understanding of riverine plastic transport is needed. To achieve this, quantification of riverine plastic transport is crucial. Here, we demonstrate how established methods can be combined to provide a rapid and cost-effective characterization and quantification of floating macroplastic transport in the River Rhine. We combine visual observations with passive sampling to arrive at a first-order estimate of macroplastic transport, both in number (10–75 items per hour) and mass per unit of time (1.3–9.7 kg per day). Additionally, our assessment gives insight in the most abundant macroplastic polymer types the downstream reach of the River Rhine. Furthermore, we explore the spatial and temporal variation of plastic transport within the river, and discuss the benefits and drawbacks of current sampling methods. Finally, we present an outlook for future monitoring of major rivers, including several suggestions on how to expand the rapid assessment presented in this paper.</p

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

A novel electrochemical process for the recovery and recycling of ferric chloride from precipitation sludge

During wastewater treatment and drinking water production, significant amounts of ferric sludge (comprising ferric oxy-hydroxides and FePO4) are generated that require disposal. This practice has a major impact on the overall treatment cost as a result of both chemical addition and the disposal of the generated chemical sludge. Iron sulfide (FeS) precipitation via sulfide addition to ferric phosphate (FePO4) sludge has been proven as an effective process for phosphate recovery. In turn, iron and sulfide could potentially be recovered from the FeS sludge, and recycled back to the process. In this work, a novel process was investigated at lab scale for the recovery of soluble iron and sulfide from FeS sludge. Soluble iron is regenerated electrochemically at a graphite anode, while sulfide is recovered at the cathode of the same electrochemical cell. Up to 60±18% soluble Fe and 46±11% sulfide were recovered on graphite granules for up-stream reuse. Peak current densities of 9.5±4.2Am-2 and minimum power requirements of 2.4±0.5kWhkgFe-1 were reached with real full strength FeS suspensions. Multiple consecutive runs of the electrochemical process were performed, leading to the successful demonstration of an integrated process, comprising FeS formation/separation and ferric/sulfide electrochemical regeneration

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

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

Nitrogen is the most crucial element in the production of nutritious feeds and foods. The production of reactive nitrogen by means of fossil fuel has thus far been able to guarantee the protein supply for the world population. Yet, the production and massive use of fertilizer nitrogen constitute a major threat in terms of environmental health and sustainability. It is crucial to promote consumer acceptance and awareness towards proteins produced by highly effective microorganisms, and their potential to replace proteins obtained with poor nitrogen efficiencies from plants and animals. The fact that reactive fertilizer nitrogen, produced by the Haber Bosch process, consumes a significant amount of fossil fuel worldwide is of concern. Moreover, recently, the prices of fossil fuels have increased the cost of reactive nitrogen by a factor of 3 to 5 times, while international policies are fostering the transition towards a more sustainable agro-ecology by reducing mineral fertilizers inputs and increasing organic farming. The combination of these pressures and challenges opens opportunities to use the reactive nitrogen nutrient more carefully. Time has come to effectively recover used nitrogen from secondary resources and to upgrade it to a legal status of fertilizer. Organic nitrogen is a slow-release fertilizer, it has a factor of 2.5 or higher economic value per unit nitrogen as fertilizer and thus adequate technologies to produce it, for instance by implementing photobiological processes, are promising. Finally, it appears wise to start the integration in our overall feed and food supply chains of the exceptional potential of biological nitrogen fixation. Nitrogen produced by the nitrogenase enzyme, either in the soil or in novel biotechnology reactor systems, deserves to have a ‘renaissance’ in the context of planetary governance in general and the increasing number of people who desire to be fed in a sustainable way in particular