Manual treatment of urban wastewater by chemical precipitation for production of hydroponic nutrient solutions

• Published in: Journal of Ecological Engineering
• Main Authors: Correia, Tânia, Regato, Mariana, Almeida, Adelaide, Santos, Teresa, Amaral, Leonor, Carvalho, Fátima
• Other Authors: CENSE - Centro de Investigação em Ambiente e Sustentabilidade
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2020
• Subjects: Antarctica; Chemical precipitation; CO capture; Hydroponics; Urban wastewater; Ecology; Evolution; Behavior and Systematics; Environmental Science(all); SDG 6 - Clean Water and Sanitation; Antarctic; Antarc*
• Online Access: http://hdl.handle.net/10362/116910; https://doi.org/10.12911/22998993/118286

Publication is funded by the Polish National Agency for Academic Exchange under the International Academic Partnerships Programme from the project "Organization of the 9th International Scientific and Technical Conference entitled Environmental Engineering, Photogrammetry, Geoinformatics - Modern Technologies and Development Perspectives". Project with financial support of FCT, I.P./MCTES through national funds (PIDDAC) and the Portuguese Polar Program (PROPOLAR). An urban wastewater treatment system was developed in Portugal for posterior in situ feasibility testing at the Bulgarian Antarctic Base, using its domestic wastewater. The aim of this system was to develop a low cost, integrated approach for wastewater treatment and production of nutrient solutions (NS) for hydroponic cultivation of lettuce (Lactuca sativa var. crispa) in Antarctic stations, or any other place where the lack of resources and logistical hardships make the wastewater treatment and reuse impractical. The wastewater treatment system consisted in manual agitation lime chemical precipitation (LCPm) and effluent natural neutralization (NN) by atmospheric CO2 carbonation reactions (with and without air injection). The resulting effluent/NS had macronutrient values (nitrogen and phosphorous) for the hydroponic cultivation of lettuce below the values of commercial NS and a high pH (pH ≈ 8). The treatment achieved a total coliform removal rate of 100%. Before the LCPm treatment system development, several lime-based reagents were tested under different reaction pH and using mechanical agitation, to access their organic matter removal efficiency, as chemical oxygen demand (COD). The best COD removal results obtained were: commercial Ca(OH)2. (pH 11.5-89%), reagent grade Ca(OH)2 (pH 11.5-79%) and CaO (pH 12.0-64%). publishersversion published