Adaptive model based control for wastewater treatment plants

In biological wastewater treatment, nitrogen and phosphorous are removed by activated sludge. The process requires oxygen input via aeration of the activated sludge tank. Aeration is responsible for about 60% of the energy consumption of a treatment plant. Hence optimization of aeration can contribute considerably to the increase of energy-efficiency in wastewater treatment. To this end, we introduce an adaptive model based control strategy for aeration called adaptive WOMBAT. The strategy is an improvement of the original WOMBAT, which has been successfully implemented at wastewater treatment plant Westpoort in Amsterdam. In this paper we propose to improve the physics-based model by introducing automatic parameter adaptation. In an experimental model setup the adaptive model based control algorithm proves to result in better effluent quality with less energy consumption. Moreover, it is able to react to the varying circumstances of a real treatment plant and can, therefore, operate without human supervision

Modelling of high-field-side high-density region with the nonlinear MHD code JOREK with kinetic neutrals

In this contribution, we have presented a benchmark of JOREK-without drifts-with kinetic neutrals against SOLPS-ITER (without drifts) and the development of the HFSHD-region in JOREK simulations with kinetic neutrals for early ITER operation (the PFPO-1 phase). Ramping up the fueling rate (in the divertor) decreases gradually the heat flux towards the divertor target. Once the ionisation front comes off the wall, cross field transport moves neutrals and plasma across the separatrix. Building up the (off-separatrix) density in the high field side. Around a critical upstream density, the plasma undergoes a sharp transition to form the HFSHD-region carried by the formation of an →−E×→−B vortex. This →−E×→−B vortex increases in strength and displaces the inner target ion flux upwards. Switching off →−E×→−B drifts strongly reduces cross-field transport and thus does not allow for the density buildup at the high-field-side. With more accurate divertor solution, JOREK can now better study the consequences in the divertor as a result of MHD instabilities, such as ELMs.</p

Modelling of high-field-side high-density region with the nonlinear MHD code JOREK with kinetic neutrals

In this contribution, we have presented a benchmark of JOREK-without drifts-with kinetic neutrals against SOLPS-ITER (without drifts) and the development of the HFSHD-region in JOREK simulations with kinetic neutrals for early ITER operation (the PFPO-1 phase). Ramping up the fueling rate (in the divertor) decreases gradually the heat flux towards the divertor target. Once the ionisation front comes off the wall, cross field transport moves neutrals and plasma across the separatrix. Building up the (off-separatrix) density in the high field side. Around a critical upstream density, the plasma undergoes a sharp transition to form the HFSHD-region carried by the formation of an →−E×→−B vortex. This →−E×→−B vortex increases in strength and displaces the inner target ion flux upwards. Switching off →−E×→−B drifts strongly reduces cross-field transport and thus does not allow for the density buildup at the high-field-side. With more accurate divertor solution, JOREK can now better study the consequences in the divertor as a result of MHD instabilities, such as ELMs.</p

Evaluation of a coupled hydrodynamic-closed ecological cycle approach for modelling dissolved oxygen in surface waters

The description of intertwined ecological processes in surface waters requires a holistic approach that accounts for spatially distributed hydrological/water quality processes. This study describes a new approach to model dissolved oxygen (DO) based on linked hydrodynamic and closed nutrient cycle ecological models. Long term datasets from the River Dommel (Netherlands) are used to determine: 1) if this methodology is suitable for modelling DO concentrations, 2) the model sensitivity to various levels of nutrients input, and 3) the DO production and consumption processes and their response to nutrient input changes. Results show that seasonal dynamics of DO are well quantified at long timescales; the sensitivity of DO to different pollutant sources exhibits significant seasonal variation and the largest influences on DO are aeration and mineralization of organic material. The approach demonstrates an ability to consider the impacts of nutrient input and long term vegetation maintenance on ecological quality

Verwerking van mest en zuiveringsslib: kansen voor synergie

Bij de verwerking van menselijke en dierlijke mest kunnen meer nutriënten en energie worden teruggewonnen. Waterzuiveraars en mestverwerkers kunnen elkaar versterken door samen in onderzoek en praktijk te werken aan nieuwe verwerkingsmethoden

Thermodynamic Properties of the Incommensurate Phase of CuGeO_3

We present high resolution measurements of the specific heat and the thermal expansion of the inorganic spin--Peierls cuprate CuGeO_3 in a magnetic field of 16 Tesla. At the transition from the incommensurate to the uniform phase both quantities show pronounced anomalies, which allow to derive the uniaxial pressure dependencies of the transition temperature. In high magnetic fields the specific heat is dominated by magnetic excitations and follows a T^3 law at low temperatures. The thermal expansion measurements show the occurrence of spontaneous strains along all three lattice constants and yield high resolution measurements of the temperature dependence of the incommensurate structural distortion. The sizes of the spontaneous strains in the incommensurate phase are significantly reduced, but both their anisotropy as well as their temperature dependencies are very similar to those in zero field.Comment: 12 pages (Latex), 4 Figs. (PS), to appear in Phys. Rev. B54 (Vol.21

Human conjunctiva organoids to study ocular surface homeostasis and disease

The conjunctival epithelium covering the eye contains two main cell types: mucus-producing goblet cells and water-secreting keratinocytes, which present mucins on their apical surface. Here, we describe long-term expanding organoids and air-liquid interface representing mouse and human conjunctiva. A single-cell RNA expression atlas of primary and cultured human conjunctiva reveals that keratinocytes express multiple antimicrobial peptides and identifies conjunctival tuft cells. IL-4/-13 exposure increases goblet and tuft cell differentiation and drastically modifies the conjunctiva secretome. Human NGFR+ basal cells are identified as bipotent conjunctiva stem cells. Conjunctival cultures can be infected by herpes simplex virus 1 (HSV1), human adenovirus 8 (hAdV8), and SARS-CoV-2. HSV1 infection was reversed by acyclovir addition, whereas hAdV8 infection, which lacks an approved drug therapy, was inhibited by cidofovir. We document transcriptional programs induced by HSV1 and hAdV8. Finally, conjunctival organoids can be transplanted. Together, human conjunctiva organoid cultures enable the study of conjunctival (patho)-physiology.</p

Human conjunctiva organoids to study ocular surface homeostasis and disease

The conjunctival epithelium covering the eye contains two main cell types: mucus-producing goblet cells and water-secreting keratinocytes, which present mucins on their apical surface. Here, we describe long-term expanding organoids and air-liquid interface representing mouse and human conjunctiva. A single-cell RNA expression atlas of primary and cultured human conjunctiva reveals that keratinocytes express multiple antimicrobial peptides and identifies conjunctival tuft cells. IL-4/-13 exposure increases goblet and tuft cell differentiation and drastically modifies the conjunctiva secretome. Human NGFR+ basal cells are identified as bipotent conjunctiva stem cells. Conjunctival cultures can be infected by herpes simplex virus 1 (HSV1), human adenovirus 8 (hAdV8), and SARS-CoV-2. HSV1 infection was reversed by acyclovir addition, whereas hAdV8 infection, which lacks an approved drug therapy, was inhibited by cidofovir. We document transcriptional programs induced by HSV1 and hAdV8. Finally, conjunctival organoids can be transplanted. Together, human conjunctiva organoid cultures enable the study of conjunctival (patho)-physiology.</p