Electrochemical Behavior of Anode-Respiring Bacteria on Doped Carbon Electrodes

Cultivating anodic respiring bacteria (ARB) on anodes doped with metal-enhanced biological growth and affected higher electocatalytic activity (ECA). The anode doped with calcium sulfide (CaS) proved more favorable for ARB than the magnetite (Fe₃O₄) or iron­(II) sulfide (FeS). Average anodic current densities of 8.4 Am^2– (Fe₃O₄), 11.1 Am^2– (FeS), and 22.0 Am^2– (CaS) were achieved as compared to that of nondoped carbon (5.1 A m^–2). Thus, CaS-doped graphite represents a promising anode material which is suitable for highly efficient bioelectrochemical systems (BES). Electrochemical evaluation during turnover and starvation using simple cycle voltammetry (CV) and derivative cycle voltammetry (DCV) indicated several extracellular electron transfer (EET) pathways characterized with lower potentials for biofilms. However, despite the high affinity of bacteria to iron, their lower ECA was kinetically attributed to the accumulation of self-produced mediators on iron-doped anodes

MOESM1 of Hydrogen production and microbial kinetics of Clostridium termitidis in mono-culture and co-culture with Clostridium beijerinckii on cellulose

Additional file 1. Additional figures and tables

Carbon and Phosphorus Removal from Primary Municipal Wastewater Using Recovered Aluminum

In this work, recovery of aluminum from coagulated primary sludge and its reuse potential as secondary coagulant were investigated. The recovery process consisted of releasing the particle-bound aluminum from primary sludge by acidification (HCl or H₂SO₄), followed by separation using centrifugation for dissolved coagulant recovery. The recovered coagulant was then reused for treating primary wastewater and overall coagulation efficiency was determined. While with fresh alum, the removal efficiencies of total suspended solids, chemical oxygen demand, total phosphorus, and total nitrogen were 85%, 65%, 80% and 33%, respectively, a drop in removal efficiency of total suspended solids and chemical oxygen demand was observed for recovered aluminum (85–60% and 65–50%, respectively). Nitrogen concentration remained almost constant with each cycle, while phosphorus in the effluent increased by 1 mg/L and 3 mg/L in the first and second cycle, respectively. Precipitation of various aluminum species was modeled for determining the recovery potential of aluminum at low pH. Preliminary cost analysis indicates that optimum recovery of aluminum occurred at a pH of 1.5 for both acids. Struvite precipitation effectively removed increased phosphorus solubilized by acidification at the end of second cycle, however, it also decreased the amount of aluminum available for recycle