Resource recovery from low strength wastewater in a bioelectrochemical desalination process.

In this research, low strength synthetic wastewaters with chemical oxygen demand less than 300 mg L-1 were treated at different concentrations in a bioelectrochemical desalination process. A process optimization model was utilized to study the performance of the photosynthetic bioelectrochemical desalination process. The variables include substrate (chemical oxygen demand) concentration, total dissolved solids, and microalgae biomass concentration in the cathode chamber. Relationships between the chemical oxygen demand concentration, microalgae, and salt concentrations were evaluated. Power densities and potential energy benefits from microalgal biomass growth were discussed. The results from this study demonstrated the reliability and reproducibility of the photosynthetic microbial desalination process performance followed by a response surface methodology optimization. This study also confirms the suitability of bioelectrochemical desalination process for treating low substrate wastewaters such as agricultural wastewaters, anaerobic digester effluents, and septic tank effluents for net energy production and water desalination.

Wetlands for Wastewater Treatment.

This paper provides a review of the treatment technologies, which utilize natural processes or passive components in wastewater treatment. In particular, this paper primarily focuses on wetland systems and their applications in wastewater treatment (as an advanced treatment unit or decentralized system), nutrient and pollutant removal (single and multiple pollutants, and metals), and emerging pollutant removal (pharmaceuticals). A summary of studies involving the plant (vegetation) effects, wetland design and modeling, hybrid and innovative systems, storm water treatment and pathogen removal is also included.

Photosynthetic microbial desalination cells (PMDCs) for clean energy, water and biomass production.

Current microbial desalination cell (MDC) performances are evaluated with chemical catalysts such as ferricyanide, platinum catalyzed air-cathodes or aerated cathodes. All of these methods improve power generation potential in MDCs, however, they are not preferable for large scale applications due to cost, energy and environmental toxicity issues. In this study, performance of microbial desalination cells with an air cathode and an algae biocathode (Photosynthetic MDC - PMDC) were evaluated, both under passive conditions (no mechanical aeration or mixing). The results indicate that passive algae biocathodes perform better than air cathodes and enhance COD removal and utilize treated wastewater as the growth medium to obtain valuable biomass for high value bioproducts. Maximum power densities of 84 mW m(-3) (anode volume) or 151 mW m(-3) (biocathode volume) and a desalination rate of 40% were measured with 0.9 : 1 : 0.5 volumetric ratios of anode, desalination and algae biocathode chambers respectively. This first proof-of-concept study proves that the passive mechanisms can be beneficial in enhancing the sustainability of microbial desalination cells.