Search Results (7)

The need arises to seek new depuration technological responses aimed at the reuse of wastewater, which requires the development and promotion of economically and environmentally sustainable technologies. In this paper, it studies an improvement to a disinfection system sustainable, low-cost, patented in 2019, and based on solar energy. The water passes through a canal of reflective material in the continuous regime, and in the batch regime, the water remains in the canal. The panels are located parallel to the lateral faces of the canal. The fraction of the radiation reflected outside the canal reaches the reflective side panels that return the radiation to the canal. These panels concentrate the radiation in the canal through reflection. The disinfectant canal with fins and side panels uses ultraviolet radiation to eliminate the bacterial load carried by treated wastewater. For this reason, the present work analyzes the incidence in the area of influence of the disinfectant canal. When reflective aluminum mirrors were installed on the sloping walls of the canal, global radiation increased by 4%, when they were used on the side panels, it increased 3%, and when the aluminum mirrors were used on the canal walls and side panels, it increased 8%. The important thing about this work is that it opens windows for improving the system through materiality so the new challenge is the search for the optimal material considering the impact on global radiation and consequently on the bacteriological elimination. Full article

In recent years, critical and secondary raw materials (CRMs and SRMs, respectively) have received great interest within the circular economy model. In this work, the mycorrhizal-assisted phytomining (MAP) system, composed of Helianthus annuus–arbuscular mycorrhizal fungus Rhizophagus intraradices–Zn-volcanic ashes, was applied in bioreactors for the recovery of CRMs (Sr, P) and SRMs (Cr, Zn, Cu, Mn, Rb, Ni) from mining wastes of the Los Cóndores mine (Argentina). Our results showed high bioaccumulation of Sr, P, Mn, and Zn in the aerial tissues, and a high root-to-shoot translocation for Mn (4.02) > Sr > P > Rb > Zn (0.84). Mycorrhization treatment increased the root-to-leaf translocation for Cr and P and prevented translocation towards flower tissues in most elements. The estimated bioextracting potential of the MAP system (290 plants) in a vegetable depuration module (VDM) ranged from 158 mg/m³ P > Zn > Mn > 15.1 mg/m³ Sr. We demonstrated a promising and cost-effective biotechnology applicable in agronomical practices, given the exclusion of toxic elements in flower parts, as well as for the recovery of CRMs and SRMs by hydrometallurgy from plant biomass. Full article

The uncontrolled disposal of olive oil mill wastewater (OMW) is hazardous for the health of water and soil, since this wastewater shows low pH and high contents of organic matter and polyphenols (PP). Lagooning is one of the most common treatment systems for agro-industrial wastewater (such as OMW), due to its low cost and easy management. Aeration allows reducing the low depuration time, which is a constraint for this system. Despite this potential feasibility, literature about OMW lagooning is not abundant. Moreover, the effects of the aeration rates, concentration of polyphenols and nitrogen shortage on depuration performance of lagoons treating OMW have not been properly explored. This study analyzes the removal rates of COD and PP, and variations of pH in OMW treated in aerated tanks at the laboratory scale simulating lagooning systems. Compared to the non-aerated tanks, aeration of OMW increased the removal rates from 61% to 90% (for COD) and from 52% to 64% (for PP). Permanent aeration was more advisable compared to intermittent flow rates. Increasing concentrations of PP noticeably reduced the COD removal rates, which were halved at a 4-fold PP concentration. In contrast, the PP removal rate was constant at every concentration experimented. Compared to the COD:N value suggested by literature for aerobic processes (100:5), a shortage in nitrogen availability reduced both COD (by about 20–25%) and PP removal rates (by 25%), the latter only when COD:N was higher 400:5. The pH was less influenced by the variations in aeration rates, PP concentration and COD:N ratio compared to COD and PP removal. This investigation provides indications about the most suitable operation parameters (airflow rates, inhibiting PP concentration, and optimal COD:N) in aerated lagooning of OMW towards environmentally sound treatments of highly polluting wastewater. Full article

In this work, mycorrhizal-assisted phytoextraction (MAP, Helianthus annuus–arbuscular mycorrhizal fungus Rhizophagus intraradices–Zn-volcanic ashes) was applied for the recovery of secondary and critical raw materials (SRMs and CRMs, respectively) from Joda West (Odisha, India) mine residues, within a novel multidisciplinary management strategy. Mine residues were preliminarily characterized by using advanced analytical techniques, and subsequently mapped, classified and selected using multispectral satellite Sentinel-2A images and cluster analysis. Selected mine residues were treated by MAP at laboratory scale, and the fate of several SRMs (e.g., Zn, Cr, As, Ni, Cu, Ca, Al, K, S, Rb, Fe, Mn) and CRMs (such as Ga, Ti, P, Ba and Sr) was investigated. Bioconcentration factors in shoots (BC_S) and roots (BC_R) and translocation factors (TF) were: 5.34(P) > BCS > 0.00(Al); 15.0(S) > BCR > 0.038(Ba); 9.28(Rb) > TF > 0.02(Ti). Results were used to predict MAP performance at larger scale, simulating a Vegetable Depuration Module (VDM) containing mine residues (1 m³). Estimated bio-extracting potential (BP) was in the range 2417 g/m³ (K) > BP> 0.14 g/m³ (As), suggesting the eventual subsequent recovery of SRMs and CRMs by hydrometallurgical techniques, with final purification by selective electrodeposition, as a viable and cost-effective option. The results are promising for MAP application at larger scale, within a circular economy-based approach. Full article

Geosmin (GSM) and 2-methylisoborneol (MIB)-induced off-flavors can cause serious problems in a recirculating aquaculture system (RAS), such as delayed harvest and increased production costs, but also damage producers’ reputation. Traditionally, off-flavors have been removed by depuration before harvesting. Rainbow trout (Oncorhynchus mykiss) and European whitefish (Coregonus lavaretus) are commercially valuable species produced for consumers, both being suitable for rearing in RAS. In this study, European whitefish and rainbow trout were raised from juvenile up to 240 g (European whitefish) and 660 g (rainbow trout) to monitor the long-term accumulation of off-flavors. The concentrations in fillet of rainbow trout reached 3.6 ng·g⁻¹ (MIB) and 5.6 ng∙g⁻¹¹ (GSM) with lipid content of 22.5%, while for European whitefish up to 3.2 ng·g⁻¹ (MIB) and 3.9 ng·g⁻¹ (GSM) were found with 14.8% in lipid content. Concentrations up to 58 ng·L⁻¹ (MIB) and 49 ng·L⁻¹ (GSM) were found in the circulating water. Based on the results, the accumulation of MIB proceeds at similar pace for both species. In the case of GSM, the accumulation started similarly for both species but proceeded more quickly for rainbow trout after 140 days of the experiment, with a statistically significant difference (p < 0.05). Full article

The treatment of wastewater, financed through environmental taxes, is key to the development of a sustainable economy. The objective of this study is to verify whether the tax loads on wastewater discharges applied in Spain are effective, allowing the costs of secondary and tertiary treatments to be financed. First, the revenues collected from taxes related to the discharge of wastewater in the different Spanish regions, which reach an average value of 0.72 €/m³, are analysed. Second, the costs of secondary wastewater treatment, prolonged aeration, activated sludge with nutrient removal, and activated sludge without nutrient removal are studied. Additionally, the costs of tertiary treatments, with environmental objectives and for reuse purposes, are considered. The analysis carried out reveals high heterogeneity in the amounts collected through taxes in the different Autonomous Communities. In some cases, these amounts do not cover the costs of the treatments. An urgent review is therefore required of the financing systems applied in order to secure a level of income that can cover all the exploitation and investment costs incurred. Full article

A detailed assessment of the cumulative cost of clean water production by a natural circulation solar thermal system is presented. The system is designed and sized for sufficient residence time for pasteurisation, in a buoyancy-driven self-compensating circuit. Since it does not consume electricity, it is suitable for developing countries or emergency locations with safe drinking water issues. The principles for design and off-design simulations are explained and discussed. The simulations were performed for seven different locations, representing variable climate conditions in selected regions where there is an evident need for safe water. The results include an exergy and exergo-economic analysis. The production capacity reaches typically from 0.04 to 0.1 m³/day per m² of solar collector depending on the location. The annual cost of water production ranges between 2.2 and 6.8 €/m³ making the proposed system fairly competitive; the energy- and price-performance of the system is compared to a reverse osmosis/photovoltaic system, representing a high-tech alternative for the purpose of water purification. Full article