Batch and continuous removal of heavy metals from industrial effluents using microbial consortia

Abstract

Bio-removal of heavy metals, using microbial biomass, increasingly attracting scientific attention due to their significant role in purification of different types of wastewaters making it reusable. Heavy metals were reported to have a significant hazardous effect on human health, and while the conventional methods of removal were found to be insufficient; microbial biosorption was found to be the most suitable alternative. In this work, an immobilized microbial consortium was generated using Statistical Design of Experiment (DOE) as a robust method to screen the efficiency of the microbial isolates in heavy metal removal process. This is the first report of applying Statistical DOE to screen the efficacy of microbial isolates to remove heavy metals instead of screening normal variables. A mixture of bacterial biomass and fungal spores was used both in batch and continuous modes to remove Chromium and Iron ions from industrial effluents. Bakery yeast was applied as a positive control, and all the obtained biosorbent isolates showed more significant efficiency in heavy metal removal. In batch mode, the immobilized biomass was enclosed in a hanged tea bag-like cellulose membrane to facilitate the separation of the biosorbent from the treated solutions, which is one of the main challenges in applying microbial biosorption at large scale. The continuous flow removal was performed using fixed bed mini-bioreactor, and the process was optimized in terms of pH (6) and flow rates (1 ml/min) using Response Surface Methodology. The most potential biosorbent microbes were identified and characterized. The generated microbial consortia and process succeeded in the total removal of Chromium ions and more than half of Iron ions both from standard solutions and industrial effluents. Keywords Waste water treatment Á Biosorption Á Microbial consortium Á Bioreactor Á Design of experiment Á Microbial immobilization Editorial responsibility: Xu Han.

Evaluation of Aspergillus tamarii NRC 3 biomass as a biosorbent for removal and recovery of heavy metals from contaminated aqueous solutions

“…Jha et al (2014) found that Cu(II) uptake by using Aspergillus lentulus biomass from industrial effluents collected from two sources was efficient. Migahed et al (2017) succeeded in removing all the chromium ions and more than half of the iron ions from both the prepared standard solutions and the real industrial effluents even in the presence of other heavy metals by using a mixture of fungal spores and bacterial biomass in batch and continuous modes to remove lead and chromium ions from the industrial effluents of four different factories.…”

Assessment of the heavy metal bioremediation efficiency of the novel marine lactic acid bacterium, Lactobacillus plantarum MF042018

“…The used cells achieved a 100% removal of Ni 2+ , Cr 2+ , Cd 2+ and Pb 2+ ions, indicating the successful ability of L. plantarum MF042018 to remove a mixture of heavy metals from the industrial effluent within 1 hr only. Furthermore, applying the microbial mass hanged in a dialysis tube is considered a significant criterion, to facilitate the collection and separation of cells from the treated industrial effluent for further use 41 .…”

Structural Changes of Bacillus subtilis Biomass on Biosorption of Iron (II) from Aqueous Solutions: Isotherm and Kinetic Studies

“…The biosorption of metal ions by B. subtilis has been studied (Al-Gheethi et al 2017;Cai et al 2018). Besides, many studies reported the biosorption of iron by various microbial biosorbents (Keshtkar et al 2016;Migahed et al 2017). However, there is very little information regarding the structural and functional changes occurring on the biomass of B. subtilis as a consequence of iron biosorption.…”