Evaluation of the efficiency of activated carbon filters based on coconut endocarp and rice husk for wastewater treatment

In developing countries, the implementation of wastewater treatment systems is often limited by high costs and restricted access to efficient technologies. The main objective of this research was to evaluate the efficiency of activated carbon filters produced from coconut endocarp and rice husks as a cost-effective alternative for wastewater treatment. These residues were chemically activated to improve their adsorption capacity, and five filter configurations were designed to evaluate their effectiveness in reducing pollutants. To this end, key physicochemical and microbiological parameters were analyzed before and after each treatment, such as pH, biological oxygen demand, chemical oxygen demand, electrical conductivity, total suspended solids, and thermotolerant coliforms. The results showed that the filters achieved significant reductions in biological oxygen demand (92 %), chemical oxygen demand (91 %), electrical conductivity (61 %) and total suspended solids (45 %). However, none of the configurations were effective in reducing thermotolerant coliform levels. The differences in efficiency between the different filter configurations highlight the influence of the composition of the activated carbon in reducing the pollutants. Filters composed mainly of rice husk-activated carbon showed greater efficiency in reducing biological and chemical oxygen demand. In comparison, those containing higher proportions of coconut endocarp-activated carbon showed lower efficiency. The results confirm that activated carbon derived from agro-industrial residues is a viable alternative for producing low-cost filters to reduce pollutants in wastewater. Thus, this work introduces a new perspective for adding value to local Andean agro-industrial residues, strengthening their environmental applications and promoting the circular economy.