Hydro-biological characterization and efficiency of natural waste stabilization ponds in a desert climate (city of Assa, Southern Morocco)

Abstract

The city of Assa is located in a saharian area characterized by an arid climate and water scarcity. Like any other saharian city in a developing country, the city is facing the challenges of rapid urbanization and the need to improve wastewater treatment and management. The main objective of this work is to assess the performance of waste stabilization ponds in an arid area. This evaluation concerns microbiological and physico-chemical monitoring over three and twelve months respectively. Microbiological results indicate bacterial elimination rates of over 90% in autumn–winter due to the effectiveness of facultative ponds with 20–25 days of retention time, water clarity, ponds depth, and high sunlight exposure and penetration. Physico-chemical parameters surpass the Moroccan standards for reuse except Ph and T0 by 20–30%, this wastewater is relatively loaded with various pollutants, especially high organic load and low oxygen content. Statistical analysis has been made by principal component analysis (PCA), and confirms that dissolved oxygen, total suspended solids, COD and BOD5 do not reach the threshold for discharge into the natural environment, and moreover their reuse. For the improvement of the quality of these waters, it is legitimate to provide an upgrade of this plant by a tertiary treatment with maturation ponds.

2-D modeling to understand the design configuration and flow dynamics of Pond-In-Pond (PIP) wastewater treatment system for reuse

“…Pond treatment systems have been widely used for treating wastewater because they are lower in capital construction costs as compared to conventional mechanical systems [23,24,25,26,27]. Ponds used for treating municipal wastewater range from aerobic to facultative to anaerobic [28] and several procedures have been developed to design these various types of ponds [29,30,31,32,33,34,35].…”

Reducción de ácido sulfhídrico mediante recirculación de efluentes en lagunas de estabilización con microalgas

“…Su diseño tiene tres objetivos principales. La eliminación de coliformes fecales y microorganismos patógenos, que representan un grave peligro para la salud causando enfermedades como: hepatitis, cólera y tifoidea entre otras importantes (Achag et al, 2021), remoción de nutrientes: nitrógeno y fósforo, con el fin de evitar la eutrofización en los cuerpos receptores (Laaksonen et al, 2017) y por último la remoción de la materia orgánica también llamada demanda bioquímica de oxígeno (DBO5), responsable del agotamiento del oxígeno disuelto necesario para el sostenimiento de los ecosistemas acuáticos (Minakshi et al, 2018). El resultado del efluente final del TAR deberá cumplir la calidad del agua referida en la NOM-001-SEMARNAT-1996, la cual indica los límites máximos permisibles (DOF, 1996).…”