Análise de viabilidade técnica da compostagem de resíduos de poda, capina, varrição e roçada: estudo de caso na Universidade Federal de Juiz de Fora

Abstract

Composting is a controlled process of accelerating the natural degradation of the organic fraction of solid waste, dry waste composting being that in which waste from afforestation and urban landscaping is composted. Aiming to make possible the composting of dry waste, this work aimed to evaluate the technical feasibility of composting waste from pruning, weeding, sweeping and mowing, analyzing the effects observed on the physical-chemical parameters inherent to the process, and on the final quality of the compost generated, on a pilot scale. For this, three open system composting windrows were evaluated at the Federal University of Juiz de Fora (UFJF), and the parameters of temperature, pH, conductivity and salinity, density, volatile solids and organic carbon, humidity, total nitrogen Kjeldahl (NTK), carbon/nitrogen ratio (C/N), cation exchange capacity (CEC), phosphorus, sulfur and potassium for 116 days. The compost generated was evaluated by means of a germination test, analysis of fresh and dry mass, and root length and part area. As a result, it was proposed to install 26 fixed temporary storage locations (LAT) in order to facilitate the logistics of storing and transporting waste within the campus, saving about 2 to 3 trips per week, in addition to up to 12 hours of work. and up to 75 km traveled by the truck weekly. In addition, results were obtained for high initial nitrogen content of the samples, of 1.5%, which resulted in an initial C/N ratio of 26.6. Thus, it was concluded that the addition of nitrogen supplement in the compost piles was not relevant. The pH resulting from the process was approximately 7, indicating a semi-matured compost, a result corroborated by the final C/N ratio greater than 20. However, the compost produced did not show toxicity in the germination test, which indicates its potential use. There was no significant difference between the piles with and without turning in any parameter, indicating that their absence was not an impediment to composting. Positive results were found regarding the quality of the compost generated, with the treatment containing 50% compost and the treatment with 75% compost having the best performance, while the treatment that obtained the worst results regarding germination and development of seedling biomass was the one that did not contain compost. Thus, the study concluded that it is technically feasible to use composting as an environmentally appropriate method of disposal of waste from weeding, sweeping, pruning and mowing generated on the university campus.