Browsing by Author "Moreira, Francisca C."
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- Finding a suitable treatment solution for a leachate from a non-hazardous industrial solid waste landfillPublication . Barbosa Segundo, Inalmar D.; Martins, Ramiro; Boaventura, Rui; Silva, Tânia F.C.V.; Moreira, Francisca C.; Vilar, Vítor J.P.The current study aimed at tackling the lack of effective treatment solutions for leachates from industrial solid waste landfills (ISWLs) through the development of a treatment train for a non-hazardous ISWL (NHISWL) leachate with low/moderate content of organics and salts and low biodegradability. The following technologies were tested: (i) coagulation using ferric chloride (FeCl3) or aluminium sulphate (Al2(SO4)3), (ii) biological oxidation, and (iii) chemical and electrochemical advanced oxidation processes (AOPs/EAOPs), including photo-Fenton oxidation using ultraviolet C (UVC) or ultraviolet A (UVA) radiation (PF-UVC or PF-UVA), anodic oxidation (AO), ozonation process and ozone (O3)-based processes. The best multistage treatment strategy included: (i) coagulation with FeCl3 for partial removal of organics (with direct impact on colour, odour and turbidity removal and biodegradability enhancement) and phosphorous, (ii) PF-UVC process for recalcitrant organics oxidation (with direct impact on colour and odour removal and biodegradability enhancement) coupled to a clarification step for removal of suspended solids, turbidity, iron and phosphorous, and (iii) biological process for removal of the generated biodegradable organics and of nitrogen compounds. Upon treatment, the NHISWL leachate fulfilled European and Portuguese requirements for discharge into aquatic systems, except for ammonium (and consequently for total nitrogen), pointing to the need to change the biological process conditions or add an air stripping step. The application of coagulation before the PF-UVC process has proved to be crucial for the fulfilment of the legislation requirements.
- Multistage treatment for olive mill wastewater: Assessing legal compliance and operational costsPublication . Vuppala, Srikanth; Paulista, Larissa Oliveira; Morais, Daniela F.S.; Pinho, Inês L.; Martins, Ramiro; Gomes, Ana I.; Moreira, Francisca C.; Vilar, Vítor J.P.A treatment train for the remediation of a raw olive mill wastewater (OMW) was investigated, aiming to comply with the emission limit values (ELVs) for direct discharge into water bodies. The following stages were proposed: (i) pre-treatment (filtration and sedimentation), (ii) coagulation, (iii) biological oxidation, and (iv) advanced oxidation process (AOP). Under the best-operating conditions for coagulation (0.8 g L- 1 of Al2(SO4)3, pH = 4.5), high removal of total suspended solids (TSS) (97%), turbidity (98%), and phenols (57%) was achieved, along with a decrease in the inhibition of the biological activity. A subsequent biological oxidation stage provided a high removal of organic matter (chemical oxygen demand (COD) removal of 73%). For the third stage, three AOPs were applied and compared – photo-Fenton with UVA radiation (PF-UVA), anodic oxidation (AO), and ozonation (O3). After 3 h of treatment, the PF-UVA process (pH = 2.8, [H2O2] = 400–500 mg L- 1, [Total dissolved iron]0 = 100 mg L- 1) allowed to meet the ELV for COD, but the other parameters exceeded the threshold, while O3 process (inlet concentration = 100 mg O3 Ndm- 3, gas flow = 0.2 Ndm3 min- 1) allowed to comply with phenols, TSS, and sulfate limits. The AO process (current density up to 200 mA cm- 2) was the least efficient AOP for all studied parameters. The operational costs for the coagulation and biological oxidation stages were estimated at 1.20 € m- 3. Regarding the most effective AOPs, ozonation presented an estimated cost 2.3-fold higher than PF-UVA (11.9 € m- 3 vs. 5.2 € m- 3).