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- Optimization of atmospheric carbonation in the integrated treatment immediate one-step lime precipitation and atmospheric carbonation. The case study of slaughterhouse effluentsPublication . Madeira, Luís Miguel; Carvalho, Fátima; Almeida, Adelaide; Ribau Teixeira, MargaridaLong carbonation time has been a common feature in the integrated process composed by immediate one-step lime precipitation and atmospheric carbonation. This work aims to understand how carbonation time can be influenced by reaction pH, as well as how reactor area/volume ratio affects carbonation time and ammonia removal, using slaughterhouse wastewater due to its variable characteristics. In the integrated immediate one-step lime precipitation and atmospheric carbonation process, the immediate one-step lime precipitation re-sults showed that the reaction pH and the type of slaughterhouse wastewater influenced the removal, however, removals were the highest at reaction pH 12. In atmospheric carbonation process, the carbonation time required to reach pH 8 was independent of the reaction pH used. Additionally, at reaction pH 12, the reactor area/volume ratios applied (from 0 to 155.4 m2/m3) showed that higher reactor area/volume ratios caused lower carbonation time, but ammonia removal was not affected. For reactor area/volume ratios of 5 and 155.4 m2/m3, 15 and 1 days were spent to reduce the pH from 11.9 to 8.2, with removals of 71 and 82.6% for NH4+ and 10 and 79.1% for calcium, respectively. High removals of total Kjeldahl nitrogen (>= 71%), biological oxygen demand (>= 80%), ammonium nitrogen (>= 52%), total phosphorus (98%), total suspended solids (>= 52%), turbidity (>= 62%), absorbance at 254 nm (>= 87%), absorbance at 410 nm (>= 83%) and oils & fats (>= 47%) were obtained using immediate one-step lime precipitation and atmospheric carbonation integrated process to treatment slaughter-house wastewater, indicating that the these process is an efficient pretreatment for slaughterhouse wastewaters.
- Reuse of treated slaughterhouse wastewater from immediate one-step lime precipitation and atmospheric carbonation to produce aromatic plants in hydroponicsPublication . Madeira, Luís Miguel Simão; Ribau Teixeira, Margarida; Sérgio Nunes; Adelaide Almeida; Fátima CarvalhoThe transition from the linear economy paradigm to the circular economy in industrial wastewater treatment is on the global agenda. The search for new simple, eco-innovative and low-cost processes for treating industrial wastewater, which can also be used by small- and medium-sized industries, has been a constant challenge to ensure environmental sustainability in all types of industries. The present work aimed to evaluate the suitability of the treated slaughterhouse wastewater (SWW) obtained by the integrated process composed of immediate one-step lime precipitation (IOSLM) and atmospheric carbonation (AC) for the production of aromatic plants by hydroponics. Results showed a significant increase in plant height of 177 and 147% and root length of 64 and 37% for Pennyroyal and Chocolate Peppermint plants, respectively, after 26 days. No signs of toxicity or symptoms of micronutrient deficiency were detected in aromatic plants.