Membrane bioreactors (MBRs) are an attractive technology for drinking water applications
because they provide the advantages of biological treatment and simultaneously mitigate the
risk of microorganism passage into the product water. However, current MBR configurations
result in inherent antagonisms between the membrane performance and the biological
process efficiency. This paper introduces a novel hybrid sorption-membrane-bioreactor
configuration that resolves these antagonisms and provides additional synergies between
process components. This process configuration consists of an upflow bed of biologically
active granular adsorption media situated directly below or adjacent to a microfiltration (MF)
or ultrafiltration (UF) membrane and is abbreviated as MBR-UFGA (UpFlow Granular
Adsorbent). In this study, a submerged-style UF membrane module was preceded by a
biologically active upflow bed of granular pyrolusite (MnO2) adsorption media used for
concurrent biological removal of ammonia and physicochemical removal of iron and
manganese. The MBR-UFGA configuration was compared to a more traditional MBR
process configuration, where the nitrifying biomass was instead located in the immediate
vicinity of the membrane for ammonia removal while physicochemical removal of metals
was achieved with the addition of a powdered activated MnO2 adsorbent and aeration. This
second process configuration is abbreviated MBR-PA (Powdered Adsorbent) and provided a
baseline for comparison of the proposed novel process. The MBR-UFGA process
configuration resulted in superior membrane hydraulic performance as it extended the
chemical cleaning intervals by over 250% when operated under the same flux and other
operating conditions. Additional experiments performed without biomass addition indicated
that the biomass or biologically derived compounds were responsible for the majority of the
accelerated fouling in the more traditional MBR-PA configuration. The novel MBR-UFGA
process also resulted in a more stable and higher level of removal for ammonia and
manganese. With the MBR-PA process, steadily decreasing biological ammonia removals
resulted from mass transfer limitations that developed as the biomass migrated from
suspension to the surface of the membrane over the course of the experimental runs.
Removal of manganese in the MBR-PA process was initially poor, but increased over time as
the concentration of the powdered adsorbent accumulated in the reactor. This research
focused on a specific drinking water application, but the findings have equally important
implications for water reuse and wastewater MBR applications. Includes 8 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 330 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 11 |
| Published : | 06/15/2003 |
