Performance linked to residence time distribution by a novel wool-based bioreactor for tertiary sewage treatment

Abstract

Laboratory-scale experiments were carried out using up-flow 7 L Submerged Aerated Filter reactors packed with wool fibre or commercial plastic pall rings, Kaldnes, (70% by volume) support media for the tertiary treatment of sewage. The performance of the wool bioreactor was more consistent than that with Kaldnes medium, for both TOC removal (93%) and SS removal (90%). Both plastic and wool-packed bioreactors achieved complete nitrification at the load of about 0.4 kgCOD/m(3)/day. The sludge yield of the wool bioreactor was almost half that of the bioreactor with Kaldnes suggesting that wool could retain residual organics and particulates. The wool however was degraded and it was concluded that wool would have to be considered as additional sacrificial adsorption capacity rather than an alternative medium. The performance was linked to the residence time distribution studies and these changes in the wool structure. Biomass growth increased the retention of the tracer in the wool reactor by, it was suggested, exposing a greater surface area. Results from the plastic media on the other hand showed increased mixing possibly by increasing the mobility of the plastic. Aeration increased the mixing in both reactors, and patterns were in all cases predominantly well-mixed.

Biological Fixed Film

“…The WQSP showed higher porosity, larger surface area and lower bulk density, indicating better efficiency of wastewater treatment. Hu et al (2012) investigated the performance of aerated filter reactors using different media for tertiary sewage treatment. They demonstrated that submerged aerated filter reactors packed with wool fibre removed more organics (93%) and solids (90%) than did the reactors with commercial plastic pall rings.…”

CFD simulation of a novel anaerobic-anoxic reactor for biological nutrient removal: Model construction, validation and hydrodynamic analysis based on OpenFOAM®

“…In fact, RTD experimental tests (Levenspiel, 1999), usually coupled to hydraulic models based on compartments such as the tank-in-series and the dispersion models, have been widely used for hydrodynamic analysis in wastewater treatment reactors. It was observed that mixing conditions (Hu et al 2012, Olive et al 2005, flow type and characteristics (Behzadian et al 2013, Autumn et al 2007, Gomez 2010, Ji et al 2012, Saragai et al 2010), dead volume (Autumn et al 2007, Hu et al 2012, Ji et al 2012, Sarathai et al 2010, channeling (Gómez 2010, Nemade et al 2010, Zeng et al 2005) and dispersal (Ji et al 2012, Nemade et al 2010, Zeng et al 2005 were observed as the most important characteristics. However, experimental RTD analysis techniques require a lot of time and resources.…”

A Novel Configuration Fluidized Bed Reactor for Nitrate Reduction and Low Strength Anaerobic Wastewater Treatment

“…Among various experimental methodologies, residence time distribution (RTD) is widely used to describe the phenomenon and liquid flow pattern not only of chemical reactors but also of biological reactors [4][5][6]. The RTD measurement is an effective tool that can help understanding and determining hydrodynamic parameters [7].…”