Biomedical subjects

J C Schippers

Publications and source records attributed to J C Schippers.

3 recordsLinked to original sources

PubMed2005

Optimising the operation of a MBR pilot plant by quantitative analysis of the membrane fouling mechanism.

In order to optimize some operational conditions of MBR systems, a MBR pilot plant equipped with a submerged hollow fibre membrane module was employed in this study. The pilot MBR was fed with real municipal wastewater and the filtration flux, backwashing interval, aeration frequency and temperature were varied. A filtration flux below 25 I/m2h is generally recommended, at below this flux, the MBR operated at sub-critical flux conditions, the filter cake was minimized and membrane fouling was mainly attributed to the membrane pore blocking. Moreover, the membrane fouling, at below 25 I/m2h, was more reversible to backwashing; above this value, backwashing became less efficient to clean the membrane. Less frequent backwashing (e.g. 600 s filtration/45 s backwashing) decreased the amount of fouling irreversible to backwashing and its performance was superior to that of frequent backwashing (e.g. 200 s filtration/15 s backwashing). The MBR suffered more fouling at low temperature conditions (e.g. at 13-14 degrees C) than at high temperature conditions (e.g. at 17-18 degrees C). A conceptual model was built up and successfully interpreted this temperature effect.

Bacteria, Aerobic↗

PubMed2005

Calibrating a side-stream membrane bioreactor using Activated Sludge Model No. 1.

Membrane bioreactors (MBRs) are attracting global interest but the mathematical modeling of the biological performance of MBRs remains very limited. This study focuses on the modeling of a side-stream MBR system using the Activated Sludge Model No. 1 (ASM1), and compares the results with the modeling of traditional activated sludge processes. ASM1 parameters relevant for the long-term biological behaviour in MBR systems were calibrated (i.e. Y(H) = 0.72 gCOD/gCOD, Y(A) = 0.25 gCOD/gN, b(H) = 0.25 d(-1), b(A) = 0.080 d(-1) and f(p) = 0.06), and generally agreed with the parameters in traditional activated sludge processes, with the exception that a higher autotrophic biomass decay rate was observed in the MBR. Influent wastewater characterization was proven to be a critical step in model calibration, and special care should be taken in characterizing the inert particulate COD (X(I)) concentration in the MBR influent. It appeared that the chemical-biological method was superior to the physical-chemical method. A sensitivity analysis for steady-state operation and DO dynamics suggested that the biological performance of the MBR system (the sludge concentration, effluent quality and the DO dynamics) are very sensitive to the parameters (i.e. Y(H), Y(A), b(H), b(A) micro(maxH) and micro(maxA), and influent wastewater components (X(I), S(s), X(s) and S(NH)).

Biomass↗

PubMed2004

Modelling the biological performance of a side-stream membrane bioreactor using ASM1.

Membrane bioreactors (MBRs) are attracting global interest but the mathematical modeling of the biological performance of MBRs remains very limited. This study focuses on the modelling of a side-stream MBR system using Activated Sludge Model No. 1 (ASM1), and comparing the results with the modelling of traditional activated sludge processes. ASM1 parameters relevant for the long-term biological behaviour in MBR systems were calibrated (i.e. Y(H) = 0.72gCOD/gCOD, Y(A) = 0.25gCOD/gN, b(H) = 0.25 d(-1), b(A) = 0.080 d(-1) and f(P) = 0.06), and generally agreed with the parameters in traditional activated sludge processes, with the exception that a higher autotrophic biomass decay rate was observed in the MBR. A sensitivity analysis for steady state operation and DO dynamics suggested that the biological performance of the MBR system (the sludge concentration, effluent quality and the DO dynamics) are very sensitive to the parameters(i.e. Y(H), Y(A), b(H), b(A), micro(maxH) and micro(maxA)), and influent wastewater components(X(I), S(S), X(S), S(NH)).

Biomass↗