Influence of organic matter and CO2 supply on bioremediation of heavy metals by Chlorella vulgaris and Scenedesmus almeriensis in a multimetallic matrix

Abstract

This research evaluated the influence of organic matter (OM) and CO2 addition on the bioremediation potential of two microalgae typically used for wastewater treatment: Chlorella vulgaris (CV) and Scenedesmus almeriensis (SA). The heavy metal (HM) removal efficiencies and biosorption capacities of both microalgae were determined in multimetallic solutions (As, B, Cu, Mn, and Zn) mimicking the highest pollutant conditions found in the Loa river (Northern Chile). The presence of OM decreased the total biosorption capacity, specially in As (from 2.2 to 0.0 mg/g for CV and from 2.3 to 1.7 mg/g for SA) and Cu (from 3.2 to 2.3 mg/g for CV and from 2.1 to 1.6 mg/g for SA), but its influence declined over time. CO2 addition decreased the total HM biosorption capacity for both microalgae species and inhibited CV growth. Finally, metal recovery using different eluents (HCl, NaOH, and CaCl2) was evaluated at two different concentrations. HCl 0.1 M provided the highest recovery efficiencies, which supported values over 85% of As, 92% of Cu, and ≈ 100% of Mn and Zn from SA. The presence of OM during the loaded stage resulted in a complete recovery of As, Cu, Mn, and Zn when using HCl 0.1 M as eluent.

Current Concentrations of Zn, Cu, and As in Piggery Wastewater Compromise Nutrient Removals in Microalgae–Bacteria Photobioreactors Due to Altered Microbial Communities

“…In addition, a large removal (48.38%) of As was also reported for mixed cultures of Chlorella vulgaris and activated sludge bacteria during 10 days of culture at 690 μg/L of As during PWW treatment [ 6 ]. These differences may be due to various cultivation conditions, such as the concentration of As and strain used, non-phosphorus limiting conditions, and the high organic matter load present in the PWW, which may affect As removal and reduce adsorption by microalgae and bacteria [ 70 , 72 ].…”

Current advances in phytoremediation and biochemical composition of Arthrospira ( Spirulina ) grown in aquaculture wastewater

“…This combination can increase the removal of N and P, providing greater biomass production of microalgae and bacteria (Li et al, 2019). The microalgae are not affected by the bacteria present due to a complex cell wall structure composed of pectin, cellulose and hemicellulose that hinders the invasion of bacteria (Saavedra et al, 2019).…”

“…The presence of heavy metals in wastewater can form biomass composed of components harmful to health after cultivation due to biosorption mechanisms. For this reason, toxicological tests must be carried out to ensure safety if the biomass or bioproducts are intended for food (human and animal) or pharmaceutical applications (Saavedra et al, 2019).…”

Adriatic cyanobacteria potential for cogeneration biofuel production with oil refinery wastewater remediation

“…phenol and other pollutants [27][28][29], including the crude oil, directly or in consortium with heterotrophic bacteria, and supplying the oxygen, are especially attractive traits [30,31]. Cyanobacteria are, similarly to many microalgae [32,33], especially efficient in dealing with heavy metals toxicity, and therefore used to decrease concentrations of heavy metals in the wastewater [34][35][36][37]. Cyanobacteria, in general, prefer relatively high ammonium (NH 4 + ) concentration for their growth, in line with their relatively high tolerance to ammonia (NH 3 ) in comparison to most of the microalgae classes [38].…”