Experimento de mineralização aeróbia para ambientes aquáticos: determinação do número de réplicas

Abstract

This study aimed to test methodological aspects related to the kinetic use of oxygen consumption as an index of mineralization process in aquatic ecosystems. The experiment comprised 10 bottles (5 liters) with water samples from Monjolinho reservoir (22° 00'S and 47° 54'W) enriched with glucose (20 mg.L-1). The solutions were previously oxygen saturated and during 33 days the dissolved oxygen concentration and the temperature were registered. The anaerobic processes were avoided by reaerations, when the dissolved oxygen concentrations were near to 2.0 mg.L-1. Concerning to the fitting of the grouping data, the total amount of oxygen used in the mineralization processes was 12.4 mg.L-1, with the daily rates of consumption (k1) and reaeration (k2) equals to 7.7 and 3.7%. The non-parametric analysis (Kruskal-Wallis) showed that the use of 1 bottle is sufficient to describe the temporal oxygen consumption evolution through the adopted experimental conditions. However, due to experimental variations, the use of 3 bottles was suggested.