Evaluation of a solar raceway pond as a continuous tertiary treatment for water disinfection in a high-Andean region

¹ Department of Chemical and Environmental Technology, Rey Juan Carlos University, ESCET, Campus de Móstoles, Madrid, Spain
² Department of Sanitary Engineering, Santiago Antunez de Mayolo University, GIAHT, Huaraz, Perú.
³ Instituto de Investigación de Tecnologías para la Sostenibilidad, Universidad Rey Juan Carlos, ESCET, C/ Tulipán s/n, 28933 Móstoles, Madrid, Spain

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Treating wastewater in high-Andean regions is difficult because low temperatures slow biological processes, yet these areas also receive intense solar radiation. This study tested a continuous-flow raceway reactor as a tertiary treatment in an activated-sludge plant in Marcará, Carhuaz province, Ancash, Peru (3,050 m a.s.l.). For six months, researchers monitored physicochemical and microbiological parameters in real field conditions. Results showed E. coli inactivation above 3.3 Log Units (LRV), strongly linked to direct solar radiation (ρ = 0.85), which confirms that solar disinfection works at high altitudes. Nutrient analysis showed only small variations in nitrogen and phosphorus species between inlet and outlet, indicating that the raceway essentially conserves nutrient levels while acting as a solar disinfection unit. Overall, the raceway system was effective for disinfection, producing effluent suitable for agricultural reuse.