Lodo de estação de tratamento de água como componente para germinação de mudas florestais

Abstract

Water Treatment Plants turn raw water into drinking water by removing unwanted particles through physical and chemical processes, generating sludge that can be highly toxic, with disposal incompatible with the guidelines of Law 12.305 / 2010, which prioritizes the possibility of reduction, reuse and recycling. Thus, the present work aimed to evaluate the chemical attributes of ETA sludge and its potential in the germination of seeds of Handroanthus impetiginosus (Mart. Ex) Mattos and Eucalyptus camaldulensis Dehnh under different substrate concentrations. The experiment was carried out in a greenhouse at the Federal University of Rondônia, Rolim de Moura / RO, from December 2018 to February 2019. The physicochemical characteristics of the sludge were evaluated by a private company and the cultivation of the species of the ipê and eucalyptus species were carried out in drained polyethylene trays with increasing concentrations of 0% ETA sludge; 15%; 30%; 45% and 60% completed with equal proportions of soil + coarse sand. The experimental design was randomized blocks with five treatments and four replications each. The germination percentage (G%) was evaluated daily and after germination stabilization, the germination speed index (IVG), the average germination time (TMG) and the average germination speed (VMG) of the seeds were calculated. The sludge was rich in nutrients and organic matter, which may contribute to aeration and water retention in the substrate, favoring seed germination. In all treatments with H. impetiginosus, there was seed germination ranging from 12.5% ​​to 90.18%, where the best germination percentages occurred in the treatments with higher concentration of ETA sludge. Considering the seed germination averages, there was a significant difference in the treatment with 45% of the sludge that presented the best results (G% = 90.18%; IVG = 42.15; GMT = 4.40; VMG = 0.224 seeds.days). -1). Regarding E. camaldulensis, there was also germination in all treatments, ranging from 10.71% to 43.75%. Being the best germination percentage the treatment with 15% sludge (G% = 34.8%) and the T4 treatment presented the best values ​​of IVG (9,32), TMG (4,72) and VMG (0,212 seeds. days-1). ETA sludge presents high concentrations of organic matter, macro and micronutrient, so it can contribute to seedling germination and growth if used in concentrations of up to 45% of ETA sludge incorporated into soil and sand.