Exploring Avoided Environmental Impacts as Well as Energy and Resource Recovery from Microbial Desalination Cell Treatment of Brine

Abstract

Seawater represents a potential resource to ensure sustainable availability of water for population and irrigation purposes, especially in some areas of the world. Desalination processes allow the production of fresh water, but they generate also brine as waste product. Sustainable brine management should be identified to ensure proper disposal and potentially resource recovery. This experimental study showed that emerging technologies such as Microbial Desalination Cells (MDCs) may provide a valuable contribution to the sustainability of the seawater desalination sector. In this paper, we report results on lab-scale desalination brine treatments applying MDCs, which allow energy savings, resource recovery, environmental impact minimization, and reduction of the organic load in municipal wastewater. Our results showed that MDCs’ treatment allows the removal of approximately 33 g of salts (62% of the total)—including chlorides, bromides, and sulphates—from 20 mL of brine within 96 h. The MDCs, according to the source of energy and the presence of mature biofilm at the anode, spent 7.2 J, 7.9 J, and 9.6 J in the desalination process, with the higher amount of energy required by the abiotic system and the lesser by the MDCs fed with just wastewater. Our approach also showed environmental and energy reductions because of potential metal recovery instead of returning them into marine environment. We quantified the avoided life cycle of human and marine eco-toxicity impacts as well as the reduction of cumulative energy demand of recovered metals. The main benefit in terms of avoided toxicity would arise from the mercury and copper recovery, while potential economic advantages would derive from the recovered cobalt that represents a strategic resource for many products such as battery storage systems.

Inorganic Carbon Assimilation and Electrosynthesis of Platform Chemicals in Bioelectrochemical Systems (BESs) Inoculated with Clostridium saccharoperbutylacetonicum N1-H4

“…We applied the same approach to calculate the amount of energy provided by the external battery in MECs during the CO 2 assimilation test. In this case, we estimated the amount of energy provided by the external battery according to Kirchhoff’s law [ 38 ], Equation (2): I b = ( V b − OCV MEC )/ R MEC where I b is the current provided by the battery b and OCV MFC is the open circuit voltage of MEC after being disconnected from the battery and achieving a constant voltage. R MEC is the internal resistance of MEC.…”

Microbial Desalination Cell for Sustainable Water Treatment: A Critical Review

“…As can be seen here, MDCs have the flexibility to be used for various kinds of saline solutions such as brine produced by a desalination plant, diluted industrial wastewater, real geothermal water, and seawater. [17][18][19][20] They produce acceptable treatment results with a desalination performance of up to 97.4% [21] and a COD removal efficiency of up to 97.8%. [20] Moreover, they can remove toxic elements such as arsenic [17] and boron [22] from water.…”

“…-Finding the effect of replacing external resistance with a power supply, -Finding the role of biofilm in the anode chamber. [18] -The brine produced by a desalination plant in Italy (Sicily Region).…”

Use of Biochar-Based Cathodes and Increase in the Electron Flow by Pseudomonas aeruginosa to Improve Waste Treatment in Microbial Fuel Cells

“…One of the disadvantages related to the direct use of solid residues in MFCs lies in the competition between fermentative microflora, usually present in organic residues, and electroactive bacteria [5,19,35,36]. Besides such a competition, the resistance opposed by solid particles to the electrons and cation flow affects the performance of MFCs fed with solid organic substrates [5,9].…”

“…A process strictly related to electrosynthesis is electrofermentation [10][11][12][13][14][15][16][17][18]. All the above-mentioned processes are indeed promising and are able to contribute to the transition to the circular economy and sustainable development [2,[19][20][21].…”