Compostagem de lodo de esgoto e resíduos de poda urbana para o desenvolvimento de mudas de Senna multijuga (Rich.) H. S. Irwin & Barneby (pau-cigarra)

Abstract

All human activities generate waste, with population growth and high industrial development as the main causes of the increase in their daily generation, such as domestic sewage, which is generated in large quantities. These materials, when sent to treatment stations, generate an environmental liability called sewage sludge, which can present toxicity to the environment, if dispersed without proper treatment. In this sense, an increase in composting as a technique for treating this type of material, requiring its mixture with the carbon source for the process to be effective, a good example of these are the crushed branches and leaves from pruning and maintenance activities. arboreal. The objective of this work was to evaluate the treatment of sewage sludge and crushed material from urban pruning, through the composting process, forming a mature organic compost and verifying its efficiency in the cultivation of seedlings of Senna multijuga (Rich.) HS Irwin & Barneby (Rich.) HS Irwin & Barneby (cicada stick). The composting was carried out in the municipal nursery of Francisco Beltrão, in the state of Paraná and, to check the progress of the process, the pH, temperature, C / N ratio, aeration, humidity and fixed and volatile solids were taken. After composting was completed, the compost was used to transplant cicada seedlings, in eight different treatments, with different different types of soil (SL), organic compost (CO) and commercial substrate (SC) {C1: 30% SL - 70% CO; C2: 70% SL - 30% CO, C3: 50% SL - 50% CO, C4 100% CO, S1: 30% SL - 70% SC, S2: 70% SL - 30% SC, S3: 50% SL - 50% SC and S4: 100% SC). The composting was carried out in triplicate, and the statistical analysis showed no difference between the piles, with the temperature of the compost piles reaching 46.18 °C in the first days, with an abrupt drop in temperature after the tenth day, the humidity of the compost remained somewhat high, with weeks when its content remained above 60%, the final pH of the pile was 7.79, the volatile solids dissipated a decrease of 8.7%, and the total organic carbon (TOC) ) showed a decrease of 4.8%. As for the phytomorphological parameters and the Dickson quality index (IQD), the Tukey test (5% significance) showed no difference between treatments. Thus, the compost is effective for the production of Pau-cicada seedlings, with the same potential as the commercial substrate used. This process reinserts two environmental liabilities in the seedling production process and, in this way, generates a cyclical system for the material from tree pruning, which will be used in the production of new seedlings with potential for application in urban afforestation.