Investigation of copper inhibition of nitrifying moving bed biofilm (MBBR) reactors during long term operations

Abstract

Copper, a prevalent heavy metal in industrial mining wastewaters, has been shown to inhibit nitrification in wastewater treatment systems. Biofilm treatment systems have an inherent potential to reduce inhibition. This study investigated the effects of copper concentration on nitrifying biofilms in moving bed biofilm reactor (MBBR) systems across long term operation using influent ammonia concentrations representative of gold mining wastewater. Conventional isotherm models did not adequately model the attachment of copper to the biofilm. Long term nitritation was shown to be uninhibited at influent copper concentrations between 0.13 and 0.61 mg Cu/L. Nitratation was inhibited with influent copper concentrations of 0.28-0.61 mg Cu/L. There was no statistical difference in biofilm characteristics, including biofilm thickness, mass and density, across all copper concentrations tested, however, changes in biofilm morphology were observed. The demonstrated resistance of the nitrifying biofilm to copper inhibition makes the MBBR system a promising technology for treating ammonia in mining wastewaters.

Design strategy and mechanism of nitrite oxidation suppression of elevated loading rate partial nitritation system

“…Biofilm mass was measured using a protocol described and modified by Delatolla et al (2008) , Ren et al (2016) , Schopf et al (2018) , and Arabgol et al (2020) . Biofilm carriers were harvested from MBBR reactors P N1 and P N2 and dried at 105°C overnight.…”

Biofouling detection methods that are widely applicable and useful across disciplines: a mini-review

“…Wood 2009), wastewater treatment (i.e. Schopf et al 2018), chemistry (i.e. Saeki et al 2021), food preservative formulation (i.e.…”

Single and joint effects of Zn and Cu to ATP pool and microbial recovery in continuous growth systems

“…An important factor affecting the response of toxic metals and microorganisms is the cumulative contact time of the microbial culture with the heavy metal, which in the short term may result in acute toxicity, but in the long term may result in acclimation, referring to the physiological adjustments occurring in response to metal exposure (gene and protein regulation), mitigating the negative effects of toxic metals on microbial growth. Schopf et al . demonstrated the resistance of nitrifying biofilms to copper inhibition, showing changes in biofilm morphology in a moving bed biofilm reactor.…”