Physical, chemical and bacteriological characterization of livestock wastewater at the Choquenaira Experimental Stationin the Altiplano

Abstract

The wastewater generated at the Choquenaira Experimental Station originates primarily from cow manure and contains high levels of organic matter, nutrients, and microorganisms, posing an environmental risk if not properly managed. The objective of this study was to characterize the physical, chemical, and bacteriological properties of this wastewater, which comes from two main sources: the dairy processing facility and the milking parlor, in order to evaluate its potential use as liquid biofertilizer under a circular economy approach. A quantitative, qualitative, and descriptive methodology was employed. Composite sampling was carried out by collecting subsamples every 30 minutes over a 12-hour period, which were then homogenized and transported to the laboratory of the Health Services Institute (ISS–UMSA). Parameters such as pH, turbidity, total suspended solids (TSS), chemical and biochemical oxygen demand (COD and BOD), ammoniacal nitrogen, and thermotolerant coliforms were analyzed using standardized methods. The results revealed a high pollutant load: COD up to 16,167 mg O₂/l and BOD of 7,420 mg O₂/l, with elevated turbidity and TSS levels. The pH ranged from acidic in the dairy facility (4.00) to nearly neutral in the milking parlor (7.30). Thermotolerant coliform counts exceeded 10⁶ MPN/100 ml. It is concluded that appropriate treatment systems are essential to reduce environmental impact and, simultaneously, to utilize the leachates as agricultural inputs, contributing to sustainable production systems in rural settings.