Comparison of complex effluent treatability in different bench scale microbial electrolysis cells

Abstract

A range of wastewaters and substrates were examined using mini microbial electrolysis cells (mini MECs) to see if they could be used to predict the performance of larger-scale cube MECs. COD removals and coulombic efficiencies corresponded well between the two reactor designs for individual samples, with 66-92% of COD removed for all samples. Current generation was consistent between the reactor types for acetate (AC) and fermentation effluent (FE) samples, but less consistent with industrial (IW) and domestic wastewaters (DW). Hydrogen was recovered from all samples in cube MECs, but gas composition and volume varied significantly between samples. Evidence for direct conversion of substrate to methane was observed with two of the industrial wastewater samples (IW-1 and IW-3). Overall, mini MECs provided organic treatment data that corresponded well with larger scale reactor results, and therefore it was concluded that they can be a useful platform for screening wastewater sources.

Recovery of biohydrogen in a single-chamber microbial electrohydrogenesis cell using liquid fraction of pressed municipal solid waste (LPW) as substrate

“…Some researchers even note that ARB is capable to directly oxidize cathodic H 2 for electron production (H 2 → 2H + + 2e -→ current) [30]. The hydrogen recycling phenomenon was also confirmed by other researchers in literature, such as Ullery and Logan [2], who, in comprising complex effluent treatability in mini and larger-scale cube MECs, documented that the cells both gave γ CE values greater than 100%, and Montpart et al [30], who, in a methanol-driven MEC, reported a γ CAT even reaching up to 296%. As a result of the occurrence of hydrogen recycling effect, net hydrogen output was reduced.…”

“…Exploring sustainable energy alternatives to fossil fuels is becoming of great importance to alleviate the energy shortage. One of the potential alternative renewable energy resources that are currently under-utilized is dissolved organic matters present in wastewater streams [2,3].…”

The impact of anode acclimation strategy on microbial electrolysis cell treating hydrogen fermentation effluent

“…Recently, Ullery and Logan (Ullery & Logan, 2014) examined the impact of anode acclimation strategy (using different substrate: acetate or domestic wastewater) on the treatment efficiency of cellulose fermentation effluent. It was found that the pre-acclimation strategy of using domestic wastewater or acetate in MECs had no significant difference in COD treatment, current generation, and coulombic efficiency.…”

Hydrogen production from continuous flow, microbial reverse-electrodialysis electrolysis cells treating fermentation wastewater

“…Higher hydrogen gas production rates could possibly be obtained by using higher MREC influent COD concentrations, as this should increase COD removal rate and stabilize anode potentials. The fermentation wastewater examined here was diluted to a concentration to be similar to those previously used in MECs (Lalaurette et al, 2009;Nam et al, 2012;Nam et al, , 2014Ullery and Logan, 2014), so the use of higher influent COD concentrations could easily be achieved. The effect of organic loading on the MREC performance, in terms of anode potentials and hydrogen gas production rates, should therefore be examined in future studies.…”

“…The volume of hydrogen produced was determined using a method based on gas concentrations relative to initial nitrogen gas concentration in the gas collection bag compared to concentrations after an addition of 10 mL of nitrogen was added to the gas bag, as previously described (Ambler and Logan, 2011;Ullery and Logan, 2014). Hydrogen production rate (Q, L H 2 /L reactor /d) was normalized to the reactor volume of the anode and cathode chambers.…”