Assessment of hybrid fixed and moving bed biofilm applications for wastewater treatment capacity increase - In situ tests in El-Gouna WWTP, Egypt

Carsten Riechelmann; Mahmoud M Habashy; Eldon R Rene; Moustafa S Moussa; Hadeel Hosney

doi:10.1016/j.chemosphere.2023.139783

Assessment of hybrid fixed and moving bed biofilm applications for wastewater treatment capacity increase - In situ tests in El-Gouna WWTP, Egypt

Chemosphere. 2024 May:355:139783. doi: 10.1016/j.chemosphere.2023.139783. Epub 2023 Aug 11.

Authors

Carsten Riechelmann¹, Mahmoud M Habashy², Eldon R Rene², Moustafa S Moussa³, Hadeel Hosney⁴

Affiliations

¹ Department of Urban Water Management, Faculty of Civil Engineering, Technische Universität Berlin, Germany.
² Department of Water Supply, Sanitation, and Environmental Engineering, IHE Delft Institute for Water Education, Westvest 7, 2611 AX, Delft, the Netherlands.
³ Director of Sustainable Development Center, Zewail City of Science and Technology, Giza, Egypt; Faculty of Engineering Mataria, Helwan University, Cairo, Egypt.
⁴ Department of Water Supply, Sanitation, and Environmental Engineering, IHE Delft Institute for Water Education, Westvest 7, 2611 AX, Delft, the Netherlands. Electronic address: h.hosney@un-ihe.org.

PMID: 37574084
DOI: 10.1016/j.chemosphere.2023.139783

Abstract

This paper provides a procedure for comparing the performance of different biofilm carrier medias and their surrounding suspended biomass through oxygen uptake rate (OUR) tests. For in situ (oxygen uptake rate (OUR) measurements, three identical lab scale biofilm reactors were set up at the El Gouna wastewater treatment plant (WWTP). In this setup, two options of media for moving-bed biofilm reactors (MBBR) and one media for fixed-bed biofilm reactors (FBBR) were compared. The WWTP also used the same carrier in a real scale hybrid application to analyze how the interactions between the carrier type and the suspended biomass influences the overall performance. The in situ OUR approach is recommended to measure the contribution of the biofilm fixed biomass under site specific conditions. Specifically, settleability and diffusion limitations are the two opposite poles that cannot be predicted adequately for mild climate conditions based on the literature. A biofilm carrier application can add but actually can also reduce the capacity in a hybrid activated sludge system: The added MBBR-media was able to grind down the sludge flocs forming a poorly settleable suspended biomass. The added FBBR-media can lead to extracellular polymeric substances (EPS) rich biofilms that contribute very little as substrate and oxygen are unavailable for the microorganisms present in the biofilm. In this application of the comparison procedure, Kaldnes K1 like MBBR media was compared with a recycling MBBR carrier option (poly propylene bottle caps) and Jäger Envirotech "BioCurlz™" FBBR media. The study showed higher average rates for the MBBR but decreased settleability. The FBBR showed higher peak rates when flushed to break up the biofilm and well settleable sludge. The determination of OUR per g of volatile solids (SOUR) showed comparable results for all the carriers and in warm conditions, only the capacity to accommodate biomass determines the contribution of the carrier.

Keywords: Attached growth biomass; Fixed-bed biofilm reactor; Hybrid activated sludge; Moving-bed biofilm reactor; Oxygen uptake rate; Suspended growth biomass.

MeSH terms

Biofilms*
Biomass
Bioreactors
Egypt
Oxygen
Sewage* / chemistry
Waste Disposal, Fluid / methods

Substances

Sewage
Oxygen