Innovative method for the brine treatment by electrokinetic principles integrated with solar photovoltaic plants.

With the growing world population and industrial production, the demand for water has been continuously increasing. By 2030, it was estimated that 60.0 % of the world population will not have access to freshwater, which is about 2.50 % of the total global water. For this, a total of over 17,000 operational desalination plants have been constructed worldwide. However, the key barriers to expansion of the desalination treatments are the brine production and energy consumption. In fact, the brine production is 50.0 % higher than the freshwater, and its treatments could account for 5.0-33.0 % of total desalination cost. Here, a new theoretical approach for brine treatments integrated to solar photovoltaic plants (PVs) to supply renewable energy to the whole system has been proposed. This approach consists in combining electrokinetic and electrochemical phenomena to dilute the brine, by using an alkaline clay with high buffering power. This method substantially desalinates the brine to produce new treated seawater, using clean energy, optimizing energetic and management costs. Some hypotheses and secondary effects should validate the model, e.g., relatively high Ca2+ promotes the electro-migration; the Cl2 production reduces the Cl- concentrations; and the production of H2 can be used to store energy. A practical example for PVPs design is shown.

Numerical solutions for the treatment brine by diffusive and migration flux using new brine-clay-seawater system.

With the growing world population and industrial production, the demand for water has been continuously increasing. By 2030, 60.0% of the world population will not have access to freshwater, which is ∼2.50% of the total global water. For this, a total of over 17,000 operational desalination plants have been constructed worldwide. However, the key barrier to desalination expansion is brine production, which is 50.0% higher than the freshwater, generating 5.0-33.0% of total desalination cost. In this paper, a new theoretical approach for brine treatments has been proposed. It consists in combining electrokinetic and electrochemical mechanisms by using an alkaline clay with high buffering power. Advanced numerical model has been carried out to estimate the ions concentrations in the brine-clay-seawater system. Analytical analyses have been also carried out to estimate the global system efficiency. Results show the feasibility of the theoretical system, its size, and usability of the clay. This model not only should clean the brine to produce new treated seawater but also it should recover useful minerals thank to the electrolysis and precipitations effects.

Optimization of energy consumptions of oxidation tanks in urban wastewater treatment plants with solar photovoltaic systems.

This paper combines solar photovoltaic (PV) to wastewater treatment plants (WWTPs). A new methodology is proposed to design solar PV to reduce energy consumptions of aeration thanks in WWTPs. New analytical equations and parameters, based on the air temperatures, solar irradiations, biological kinetics, dissolved oxygens, mechanical oxygenations, are introduced to obtain the peak power of PV that maximize the auto-consumptions of aeration blowers installed in the oxidation tanks of WWTPs. The method allows a direct preliminary design and a calibrated estimation for energy power. To justify this method, three aspect are mainly discussed: (i) the oxidation tanks consume up to 30% of the energy of a WWTP; (ii) the temperature of wastewater is variable during the year, in the smaller WWTPs; (iii) the dissolved oxygen reduces, increasing temperature of wastewater. This methodology will support the sector in making decision over PV investments, helping wastewater utilities to consider sustainable management practices. Therefore, a further contribute to develop the integration of renewable energy sources combined with wastewater sectors is activated.