title: Sustainable treatment of different high-strength cheese whey wastewaters: an innovative approach for atmospheric CO2 mitigation and fertilizer production.
abstract: Raw cheese whey wastewater (CWW) has been treated by means of FeCl3 coagulation-flocculation, NaOH precipitation, and Ca(OH)2 precipitation. Three different types of CWW were considered: without cheese whey recovery (CWW0), 60 % cheese whey recovery (CWW60), and 80 % cheese whey recovery (CWW80). Cheese whey recovery significantly influenced the characteristics of the wastewater to be treated: organic matter, solids, turbidity, conductivity, sodium, chloride, calcium, nitrogen, potassium, and phosphorus. Initial organic load was reduced to values in the interval of 60-70 %. Application of FeCl3, NaOH, or Ca(OH)2 involved additional chemical oxygen demand (COD) depletions regardless of the CWW used. Under optimum conditions, the combination of 80 % cheese whey recovery and lime application led to 90 % reduction in COD. Turbidity (99.8%), total suspended solids (TSS) (98-99 %), oils and fats (82-96 %), phosphorus (98-99 %), potassium (96-97 %), and total coliforms (100 %) were also reduced. Sludge generated in the latter process showed excellent settling properties. This solid after filtration and natural evaporation can be used as fertilizer with limitations due to its saline nature. In an innovative, low-cost, and environmentally friendly technology, supernatant coming from the Ca(OH)2 addition was naturally neutralized in 4-6 days by atmospheric CO2 absorption without reagent addition. Consequently, a final aerobic biodegradation step can be applied for effluent polishing. This technology also allows for some atmospheric CO2 mitigation. Time requirement for the natural carbonation depends on the effluent characteristics. A precipitate rich in organic matter and nutrients and depletions of solids, sodium, phosphorus, magnesium, Kjeldahl, and ammoniacal nitrogen were also achieved during the natural carbonation.
authors.affiliation: Departamento de Tecnologias e Ciências Aplicadas, Escola Superior Agrária de Beja, Instituto Politécnico de Beja, Rua Pedro Soares, Apartado 158, 7801-902, Beja, Portugal. anaritaprazeres@gmail.com.|Departamento de Ingeniería Química y Química Física, Universidad de Extremadura, Avenida de Elvas S/N, 06071, Badajoz, Spain. anaritaprazeres@gmail.com.|Centro de Biotecnologia Agrícola e Agro-Alimentar do Alentejo (CEBAL)/Instituto Politécnico de Beja (IPBeja), Rua Pedro Soares S/N-Campus IPBeja/ESAB, Apartado 6158, 7801-908, Beja, Portugal. anaritaprazeres@gmail.com.
authors.forename: Ana R
authors.initials: AR
authors.lastname: Prazeres
authors.affiliation: Departamento de Ingeniería Química y Química Física, Universidad de Extremadura, Avenida de Elvas S/N, 06071, Badajoz, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Rivas
authors.affiliation: Departamento de Tecnologias e Ciências Aplicadas, Escola Superior Agrária de Beja, Instituto Politécnico de Beja, Rua Pedro Soares, Apartado 158, 7801-902, Beja, Portugal.
authors.forename: Úrsula
authors.initials: Ú
authors.lastname: Paulo
authors.affiliation: Departamento de Tecnologias e Ciências Aplicadas, Escola Superior Agrária de Beja, Instituto Politécnico de Beja, Rua Pedro Soares, Apartado 158, 7801-902, Beja, Portugal.
authors.forename: Filipa
authors.initials: F
authors.lastname: Ruas
authors.affiliation: Departamento de Tecnologias e Ciências Aplicadas, Escola Superior Agrária de Beja, Instituto Politécnico de Beja, Rua Pedro Soares, Apartado 158, 7801-902, Beja, Portugal.
authors.forename: Fátima
authors.initials: F
authors.lastname: Carvalho
mesh_terms: D001673:Biodegradation, Environmental; D002245:Carbon Dioxide / Q000737:chemistry*; D002611:Cheese / Q000032:analysis*; D005308:Fertilizers; D007220:Industrial Waste; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000737:chemistry*; D000067796:Whey / Q000737:chemistry*
chemical_list: D002245:Carbon Dioxide; D005308:Fertilizers; D007220:Industrial Waste; D062065:Wastewater
keywords: Atmospheric CO2 mitigation; Biodegradability; Cheese whey recovery; Physicochemical processes; Sludge characterization; Sludge filterability