Fate and Biotransformation of Metal and Metalloid Species in Biological Wastewater Treatment Processes

Abstract

Suspended and attached growth wastewater treatment processes are widely used for the removal of biodegradable organic constituents and nutrients from wastewater. The frequent detection of toxic metals and metalloids in wastewater contributed to the publishing of numerous papers in the past, investigating their presence, toxicity and behavior in biological wastewater treatment systems (BWTS). In most of these studies, data were referred to total element concentration. However, nowadays it is generally accepted that toxicological and physicochemical properties are differentiated according to elemental speciation. The literature review revealed that there are enough studies investigating chromium species presence, toxicity, fate and biotransformation in BWTS, whereas there are fewer data for organotin compounds. Even less studies exist for arsenic, mercury and selenium species. Most of the results are referred to the activated sludge process. The biotransformation mechanisms are element-dependent. The reduction of Cr(VI) to Cr(III), the sequential debutylation of tributyltin and triphenyltin to inorganic tin, the oxidation of As(III) to As(V) and their methylation to organoarsenicals have been observed. Despite the gaps in the literature, these preliminary, in many cases, results indicate that biological wastewater treatment processes could be used in the future for the detoxification of metal-and metalloid-laden wastewater, allowing the reuse of wastewater and sludge.

Bioadsorbents for remediation of heavy metals: Current status and their future prospects

“…Biosorption is the property exhibited by inactive, non-living substances of biological origin to bind and to accumulate metal ions from aqueous solution [23,24]. In other words the interaction between the biomass and the metal ions is physico-chemical, metabolism independent process with the underlying mechanism being absorption, adsorption, ion exchange, surface complexation and precipitation [24][25][26]. Bioaccumulation is another technology using living biomass for heavy metal removal.…”

Adsorption isotherm and kinetics analysis of hexavalent chromium and mercury on mustard oil cake

“…Biosorption is the property exhibited by inactive, non-living substances of biological origin to bind and to accumulate metal ions from aqueous solution [23,24]. In other words the interaction between the biomass and the metal ions is physico-chemical, metabolism independent process with the underlying mechanism being absorption, adsorption, ion exchange, surface complexation and precipitation [24][25][26]. Bioaccumulation is another technology using living biomass for heavy metal removal.…”

Mercury removal from municipal secondary effluent with hydrous ferric oxide reactive filtration

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