Dunia E. Santiago

Reuse and minimization of desalination brines: a review of alternatives

Abstract Desalination is currently one of the available solutions to the problem of the lack of water present in most countries due to the global increase in water demand. One of the desalination plants main problem is the large amount of reject brine produced, which can very often severely damage the receiving environment. Nowadays, the management of this residue is based mainly in the dilution prior to the discharge. However, there are many emerging alternative technologies that can be combined to achieve a minimization and valorization of brine and thus an appropriate management. This article introduces and describes briefly the set of available techniques. Each alternative has been assessed in terms of technology, economic and environmental merits, resulting in a numeric table.

Treatment of wastewater containing imazalil by means of Fenton-based processes

AbstractThis work studies the elimination, mineralization and detoxification through Fenton-based processes of wastewaters contaminated with the fungicide imazalil as a result of the postharvest treatment of bananas. Fe(II) and H2O2 concentrations were optimized for degradation of the corresponding imazalil concentrations. The activity of the imazalil degradation process was studied in deionized water and in simulated and real agro-industrial wastewaters. Results show that the water matrix had no detrimental effect on wastewater treatment when using the Fenton technique, but optimal iron content had to be increased when applying the photo-Fenton process. Even so, the optimal iron and H2O2 contents required for the photo-Fenton reaction were 6 times and 50% lower, respectively, than for the Fenton procedure. Solar pilot plant tests confirmed the detoxification of two agro-industrial wastewater effluents containing imazalil.

Reuse of SWRO brine for the production of carotenoids from Dunaliella salina and removal of macronutrients

Abstract This research determines the advantages of the use of brine from reverse osmosis seawater desalination processes as hypersaline culture media to grow Dunaliella salina. In this work, we evaluated the growth of a new strain of D. salina (Ds. Janubiense-ITC5.105) cultured in residual brine and in artificial hypersaline media compared with the productivity of a well-established strain of this species (Ds. BCA421-ITC5.003). Parameters such as concentration of chlorophylls a and b and total carotenoids accumulated by the two strains throughout the cultivation course were established. The results show maximum biomass yield of 26.44 g m−2 d−1 for Ds. BCA421-ITC5.003 grown in a controlled media with similar salinities to that of desalination brine; and maximum carotenoids productions of 20.93 mg m−2 d−1 for Ds. Janubiense-ITC5.105 grown in brine from seawater desalination processes. This SWRO brine would be an ideal medium to grow this kind of species at low cost in areas with seawater desalination plant...

Valorisation of a by-product from the TiO2 pigment industry for its application in advanced oxidation processes

AbstractThe aim of this study was to find a recycling use for waste material (WTiO2) that results from the extraction process of TiO2 from ilmenite in the pigment industry. In view of its high TiO2 content, the photocatalytic activity of this material was tested in the degradation of humic and fulvic acid substances (HFAs) and showed low levels of photoactivity, as was the case for the commercial photocatalyst Aeroxide TiO2 P25 (P25). However, due to its high Fe3+ content, an important application was observed for WTiO2 as an HFA coagulant and catalyst in Fenton and photo-Fenton processes. A two-stage process of coagulation and photo-Fenton treatment was subsequently designed and conducted at laboratory and small pilot scale. High percentages (above 95%) were obtained in total organic carbon (TOC) removal.