Simultaneous Treatment of Agro-Industrial and Industrial Wastewaters: Case Studies of Cr(VI)/Second Cheese Whey and Cr(VI)/Winery Effluents

Prospects for humic acids treatment and recovery in wastewater: A review

Clean water shortages require the reuse of wastewater. The presence of organic substances such as humic acids in wastewater makes the water treatment process more difficult. Humic acids can significantly affect the removal of heavy metals and other such toxins. Humic acids is formed by the decomposition and transformation of animal and plant remains by microorganisms, and naturally exists in soil and water. It is necessary to degrade and remove humic acids from wastewater. As it seriously human health, effective technologies for removing humic acids from wastewater have attracted great interest over the past decades. This study compared existing techniques for removing humic acids from wastewater, as well as their limitations. Physicochemical treatments including filtration and oxidation are basic and key approaches to removing humic acids. Biological treatments including enzyme and fungi-mediated humic acids degradation are economically feasible but require some scalability. In conclusion, the integrated treatment processes are more significant options for the effective removal of humic acids from wastewater. In addition, humic acids have rich utilization values. It can improve the soil, increase crop yields, and promote the removal of pollutants.

Decaffeination of wastewater using activated carbon produced from velvet tamarind-pericarp (Dialium Guineense)

Adsorption of caffeine from an aqueous solution was carried out using Velvet Tamarind-Pericarp, activated with H₃PO₄. The adsorbent was characterized using a scanning-electron microscope and the Brunauer-Emmett-Teller. Parameters such as activating agent concentration (80 wt.% in 100 mL solution), initial caffeine concentration of 5-40 g/L, pH of 0-14, and residence time 0-90 minutes, were investigated. Improved adsorptive capacities were seen at increased acid concentrations, with the highest removal rate obtained at a pH of 6. The highest residence time and adsorbent concentrations were obtained at 40 min and 10 g/L. The surface adsorption of the adsorbent obeyed the Langmuir Isotherm, while the regression coefficients conformed to the pseudo-second-order kinetic model for the remediation of caffeine with DG-AC. The highest amount of caffeine removed per gram DG is 72.60 mg.g^-1. From the thermodynamic study, the caffeine adsorption was feasible, spontaneous, entropy-driven, and endothermic. These data show that the use of DG-AC can be a good alternative to other expensive methods for caffeine remediation. The Pseudo - first/second-order kinetic results gave R² values of 0.95 and 0.99, other parameters such as entropy (ΔS°) and enthalpy (ΔH°) are 0.06 (kJmolK) and (19.21) (kJmolK).

Dairy By-Products: A Review on the Valorization of Whey and Second Cheese Whey

The search for new food products that promote consumers health has always been of great interest. The dairy industry is perhaps the best example regarding the emergence of new products with claimed health benefits. Cheese whey (CW), the by-product resulting from cheese production, and second cheese whey (SCW), which is the by-product of whey cheese manufacture, have proven to contain potential ingredients for the development of food products with improved nutritional characteristics and other functionalities. Nowadays, due to their nutritional quality, whey products have gained a prominent position among healthy food products. However, for a long time, CW and SCW were usually treated as waste or as animal feed. Due to their high organic content, these by-products can cause serious environmental problems if discarded without appropriate treatment. Small and medium size dairy companies do not have the equipment and structure to process whey and second cheese whey. In these cases, generally, they are used for animal feed or discarded without an appropriate treatment, being the cause of several constraints. There are several studies regarding CW valorization and there is a wide range of whey products in the market. However, in the case of SCW, there remains a lack of studies regarding its nutritional and functional properties, as well as ways to reuse this by-product in order to create economic value and reduce environmental impacts associated to its disposal.

Recent Advances in Water and Wastewater Treatment with Emphasis in Membrane Treatment Operations

The present Special Issue brought together recent research findings from renowned scientists in this field and assembled contributions on advanced technologies that have been applied to the treatment of wastewater and drinking water, with an emphasis on novel membrane treatment technologies. The 12 research contributions highlight various processes and technologies that can achieve the effective treatment and purification of wastewater and drinking water, aiming (occasionally) for water reuse. The published papers can be classified into three major categories. (a) First, there are those that investigate the application of membrane treatment processes, either directly or in hybrid processes. The role of organic matter presence and fouling control is the main aim of the research in some of these studies. (b) Second, there are studies that investigate the application of adsorptive processes for the removal of contaminants from waters, such as arsenic, antimony, or chromate, with the aim of the efficient removal of the toxic contaminants from water or wastewater. (c) Lastly, there are studies that include novel aspects of oxidative treatment such as bubbleless ozonation.