Appraisal of Super-Fast Membrane Bioreactors by MASM—A New Activated Sludge Model for Membrane Filtration

Abstract

The structure of existing activated models is inherently deficient in reflecting the major role of the membrane filtration. The study developed a novel model, MASM, for the membrane activated process. The effective filtration size imposed by the membrane module, entrapping larger particles, was adopted as the basis of the proposed model. The model defines a modified form of COD fractionation that accounts for the captured COD fractions as additional model components and utilizes related mass-balance relationships. It was implemented to test the fate of soluble hydrolyzable COD and the system performance of super-fast membrane activated sludge based on real data for the characterization and process kinetics of domestic sewage and denim processing effluents. Model evaluation was carried out for parallel systems with gravity settling and membrane filtration operated at a sludge age range of 0.5–2.0 d. Results reflected significantly better performance by the super-fast membrane activated sludge system for both wastewaters, underlining that it was crucially important to account for the captured COD fractions to provide an accurate evaluation of system behavior and effluent quality. This should also be identified as the major shortcoming of the ASM models for evaluating and predicting the system performance of activated sludge configurations with membrane separation.

Efficient energy recovery from wastewater with high rate activated sludge process: oversights and misguidances

“…3, by the modeling results of a recent study, which was devoted to the appraisal of super-fast activated sludge systems. 39 The result presented in the figure also enables one to envisage the major handicap of the contact-stabilization process, which is operated with the lowest ⊔ H level in the contact tank, among all HRAS configurations.…”

“…The stoichiometry of the activated sludge process for organic carbon removal is well studied, since it is a prerequisite for defining the mechanistic relationship between substrate consumed, biomass formed and sludge generated, in order to evaluate and check the validity of experimental findings related to energy conservation. Recent studies developed a novel stoichiometric approach for defining excess sludge components per unit flow rate so that each component of p X could be expressed in mg L −1 as a fraction of influent COD C T1 39,40 : where p XS is the unit disposal of remaining slowly biodegradable COD X S , p XH is the unit generation of active heterotrophic biomass X H , p XP is the unit generation of particulate metabolic products X P and p XI is the unit disposal of influent particulate inert COD X I .…”

Anatomy of super‐fast activated sludge process with gravity settling for biodegradation and energy recovery potential ‐ a review

“…A recent review on the performance of super‐fast MBRs (θ X lower than 2.0 days) designed for organic carbon removal and conducted with different substrates provided reliable experimental results that ‘… high sludge age values merely represent a design luxury for the MBR systems since complete removal of soluble biodegradable substrate could be achieved at θ X < 2.0 days .’ 52 . A new study proposed a novel model, MASM, for the membrane activated sludge process, which disclosed a significant but so far overlooked system attribute of much lower effluent COD levels; this was experimentally justified by means of entrapment and recycling of larger size particles compared to the effective filtration size of the membrane module 53 …”

“…52 A new study proposed a novel model, MASM, for the membrane activated sludge process, which disclosed a significant but so far overlooked system attribute of much lower effluent COD levels; this was experimentally justified by means of entrapment and recycling of larger size particles compared to the effective filtration size of the membrane module. 53…”

Role of experimental support as an essential component of sustainable design of the activated sludge process for nitrogen removal

“…This study relies on the stipulation that the process kinetics and stoichiometry provided by the biokinetic models 23 should be recognized as the basic ingredients of system design. Thus, available information in these models should be incorporated with accurate experimental support derived from the wastewater to be treated, both in terms of the general characteristics and the biochemical processes involved.…”