Influência da forma de disposição dos resíduos de pescado sobre o comportamento da temperatura e da redução de sólidos totais e voláteis

Abstract

During fish production, waste is generated, which is generated throughout the production process. To dispose of this waste, there are different methods that can be used, and these methods can have different behaviors in the waste degradation and treatment process. The objective of the research was to evaluate the influence of the way fish waste is disposed of on the behavior of temperature and the reduction of total solids (TS) and volatile solids (VS). The research was carried out at Embrapa Agropecuária Oeste. The disposal methods used were composting and burial method, for which waste from fish slaughter was used. This waste was arranged in cells made of masonry measuring approximately 1m2. In the composting method, the waste was arranged in two conditions, both using wood shavings, where the waste was interspersed in layers together with the wood shavings, the difference is that in one of the conditions biochar was added at a dose of 10% in relation to waste. In the burial method, the waste was also arranged in two conditions, in both conditions the soil was covered with a layer of wood shavings, after which around 150 kg of waste was added, in one of the conditions the waste was covered first with wood shavings and then with soil, in the other condition only soil was used for covering. In composting, management was carried out, with forced aeration in the first 6 weeks and turning at 50, 70 and 90 days. Regarding the burial method, there was no type of management. Composting lasted 130 days, while the burial method remained for 220 days. During this entire period of the processes, the temperature was measured, with the aid of data loggers, inserted at different points inside the cells. During composting, at 70 and 130 days, samples were collected to evaluate the reductions of TS and VS. In the burial method, these collections occurred after 130 and 220 days. The addition of 10% biochar favored the increase in temperature after the 10th week of composting, reaching a temperature of 65.9 in the 15th week, in addition. ST and SV reductions were greater when this additive was used. In the burial method, the addition of the shavings layer to the cover along with the soil caused an increase in temperature compared to covering only with soil throughout the process. ST reductions in buried waste after 130 days were 44.4% when wood shavings and soil were used for covering, whereas when only soil was used for covering, the reduction was only 10.22%. Therefore, the best way to transform a waste into a compost that can be used for cultivation is to carry out composting, where it reaches higher temperatures and performs sanitation. Furthermore, the burial method is not suggested, as this method does not reach high temperatures, and thus there is no formation of an environment where there is the development of microorganisms that carry out degradation, without sanitization and reduction of ST and SV of buried waste.