Tertiary treatment of coke-oven wastewater using suspended and immobilized whole live cells of constructed bacterial–microalgal consortium: modeling and optimization using ANN–GA hybrid methodology

Abstract

Coke-oven wastewater (CW), containing an array of toxic pollutants above permissible limits even after conventional primary and secondary treatment, needs a tertiary (polishing) step to meet the statutory limit. In the present study, a suitable bacterial–microalgal consortium (Culture C) was constructed using bacterial (Culture B: Bacillus sp. NITD 19) and microalgal (Culture A: a consortium of Chlorella sp. and Synechococcus sp.) cultures at different ratios (v/v) and the potential of these cultures for tertiary treatment of CW were assessed. Culture C4 (Culture B:Culture A = 1:4) with inoculum size: 10% (v/v) was selected for the treatment of wastewater since the maximum growth (3.08 ± 0.57 g/L) and maximum chlorophyll content (4.05 ± 0.66 mg/L) were achieved for such culture in PLE-enriched BG-11 medium. During treatment of real secondary treated coke-oven effluent using Culture C4 in a closed photobioreactor, the removal of phenol (80.32 ± 2.76%), ammonium ions (47.85 ± 1.83%), fluoride (65.0 ± 4.12%), and nitrate (39.45 ± 3.42%) were observed after 24 h. In a packed bed bioreactor containing immobilized C4 culture, the maximum removal was obtained at the lowest flow rate (20 mL/h) and highest column bed height (20 cm). Artificial intelligence-based techniques were used for modeling and optimization of the process.

Current and future perspectives of a microalgae based circular bioeconomy to manage industrial wastewater– A Systematic Review

“…Various growth systems have been analysed to determine the working effectiveness of a mixed culture including a biofilm and immersion system, on the disrupting nature of microalgal cell walls by bacteria. This has raised a prompt research question on whether it could be used as a harvesting technique to extract the nutrients inside the bacterial cell wall (Rai et al, 2023). The bacteria also act as scavengers and consume the dead microalgae and other contaminants within the consortia (Vishwakarma et al, 2022).…”

“…It has been found that the artificial polyculture system produced a higher percentage (60%) of biomass than the naturally constructed system. The tolerance of stress conditions was found to be higher in artificial pond systems than in the natural system (Rai et al, 2023).…”