Electrochemical struvite precipitation from digestate with a fluidized bed cathode microbial electrolysis cell

Cusick, Roland D.; Ullery, Mark L.; Dempsey, Brian A.; Logan, Bruce E.

doi:10.1016/j.watres.2014.01.051

Cited by 139 publications

(75 citation statements)

References 40 publications

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“…P was recovered in the cathode chamber, where proton consumption converts the neutral solution to alkaline. Similar results were reported by (Cusick et al, 2014;You et al, 2015), where high P removal was achieved by MEC (85 %) and MFC (82 %), respectively. Cathode pH was affected by applied voltage;…”

supporting

confidence: 88%

“…No deterioration in 15 current (in OCV) was noticed, which confirms the effect of P recovery on the current. Similar findings were observed in previous studies (Almatouq & Babatunde, 2016;Cusick et al, 2014). After each cycle, the cathode electrode was replaced with a new electrode and the used electrode was removed for maintenance.…”

supporting

confidence: 77%

“…In addition, NH 4 removal was observed to increase when applied voltage was increased, ranging from 0.7 ± 0.1 mm at 0.4 V to 2.25 ± 0.2 mm at 1.2 V. However, calculating NH 4 concentration in the cathode effluent was challenging. The concentration of NH 4 in the cathode effluent varied and fluctuated in each cycle, due to ammonia volatilization caused by the high pH (Cusick et al, 2014). …”

mentioning

confidence: 99%

“…MECs have been used for different applications such as hydrogen production , methane production (Ding et al, 2016), ammonium recovery (Kuntke et al, 2014) and P recovery (Cusick & Logan, 2012;Cusick et al, 2014). The recovery of P in MEC has not been studied in depth; few studies have focused on the topic to date.…”

mentioning

confidence: 99%

“…A dual chamber MEC with a fluidized bed cathode was suggested to enhance P removal. A dual chamber MEC has better separation between the anode and cathode, which helps induce pH increases in the cathode chamber (Cusick et al, 2014). A fluidized bed cathode was used to inhibit scale formation on the cathode surface.…”

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confidence: 99%

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Concurrent hydrogen production and phosphorus recovery in dual chamber microbial electrolysis cell

Almatouq

Babatunde

2017

Bioresource Technology

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Concurrent hydrogen (H 2 ) production and phosphorus (P) recovery were investigated in dual chamber microbial electrolysis cells (MECs). The aim of the study was to explore and understand the influence of applied voltage and influent COD concentration on concurrent H 2 production and P recovery in MEC. P was efficiently precipitated at the cathode chamber and the precipitated crystals were verified as struvite, using X-ray diffraction and scanning electron microscopy analysis. The maximum P precipitation efficiency achieved by the MEC was 95%, and the maximum H 2 production rate was 0.28 m 3 -H 2 /m 3 -d. Response surface methodology showed that applied voltage had a great influence on H 2 production and P recovery, while influent COD concentration had a significant effect on P recovery only. The overall energy recovery in the MEC was low and ranged from 25 ± 1 to 37 ± 1.7 %. These results confirmed MECs capability for concurrent H 2 production and P recovery.Keywords: Bio-electrochemical System; Phosphorus Recovery; Microbial Electrolysis Cell; Struvite; Response Surface Methodology IntroductionDue to population growth, the global demand for unsustainable resources is rising. As a result, concerns around resource depletion are increasing. Phosphorus is one of the most 2 important unsustainable nutrients on our planet. Phosphorus is essential for all forms of life, especially for plant growth. Unfortunately, estimates show that phosphorus rocks will be depleted within the next 50-100 years (Cooper et al., 2011). Therefore, alternative sources of phosphorus should be discovered to balance the high demand for phosphorus. Magnesium ammonium phosphate (struvite) is one of most common phosphate fertilizers that can be recovered from different streams of wastewater. Struvite is an efficient slow release fertilizer that can be used for crop growth, and is an excellent alternative for phosphate rocks (Rahman et al., 2014).Struvite precipitation occurs in the equimolecular concentration of magnesium (Mg), ammonium (NH 4 ) and (P); these elements combine with water to form struvite. The precipitation of these components is also highly dependent on pH, where struvite starts to precipitate at pH > 8 (Doyle & Parsons, 2002). The most common methods for P recovery as struvite are chemical addition and carbon dioxide stripping through aeration. These processes are effective for struvite precipitation; however, the operation cost is too high. Using chemical addition to raise the solution's pH can account for up to 97% of struvite cost (Jaffer et al., 2002;Morales et al., 2013).Microbial electrolysis cells (MECs) are a new and promising approach for hydrogen (H 2 ) production from organic matter, including wastewater and other renewable resources. In MECs, electrochemically active bacteria oxidise organic matter and generate CO 2 , electrons and protons. The bacteria transfer the electrons to the anode and the protons are released into the solution. The electrons then travel through a wire to a cathode and combine wit...

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supporting

confidence: 88%

supporting

confidence: 77%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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