Modelling of biological Cr(VI) removal in draw-fill reactors using microorganisms in suspended and attached growth systems

Molasses as an efficient low-cost carbon source for biological Cr(VI) removal

“…Although there are several studies on Cr(VI) reduction in the literature, only a few use attached growth reactors especially under batch operating mode. According to these studies, Cr(VI) removal by immobilized microorganisms presents advantages as higher removal rates are achieved even with high initial concentrations (up to 110 mg/L) [28][29][30].…”

Modeling microbial growth and dynamics

“…Wastewater treatment systems are thus usually open systems with, heuristically speaking, an influx of fresh wastewater and an efflux of a mixture of bulk fluid and microbial biomass. The microbial community is in part a function of the composition of the available substrate, e.g., sewage (Henze et al 2000;Makinia 2010) or industrial wastewater (Debik and Coskun 2009;Tekerlekopoulou et al 2013;Amin et al 2014), which in turn depends on the composition and activity of the microbial community. Consequently, the management of wastewater treatment processes, such as the activated sludge process (Ardern and Lockett 1914), membrane bioreactors (Brindle and Stephenson 1996), or membrane-aerated biofilm reactors (Casey et al 1999), is often closely related to the management of microbial communities and activities by providing optimal growth conditions for a target community.…”

“…Important parameters are the composition and flow rate of the influent wastewater, the average microbial residence time in the reactor, and the availability of oxygen that triggers anaerobic or aerobic processes. The modeling of microbial growth is often realized using differential equations describing microbial growth in well-mixed or homogeneous systems (Andrews 1974;Henze et al 1987;Tekerlekopoulou et al 2013). However, microbial growth can also be modeled along a wide range, from implicit in substrate uptake (Batstone et al 2002) to modeling changes in community structure at the level of individual species or even cells (Lu et al 2007;Ramirez et al 2009;Lardon et al 2011;Storck et al 2014).…”

“…The model by Rial et al (2011) used a Weibull function to describe the dose-dependent variations in growth parameters for copper, nickel, and cadmium. The model by Tekerlekopoulou et al (2013) incorporated an optimum Cr(VI) concentration at which the growth rate of chrome-reducing bacteria is maximized. Similarly, substrate inhibition has been modeled in multilayered biofilms in bioreactors (Soda et al 1999).…”

Simultaneous bioremediation of Cr(VI) and phenol from single and binary solution using Bacillus sp.: Multicomponent kinetic modeling

“…Kinetics of growth of microorganism is quite important to design the bioaccumulation and biodegradation system utilizing living cells. The specific growth rate (h À1 ) for first order kinetics and exponential growth phase is calculated according to the following equation [32][33][34][35].…”