Avaliação do efluente de fossa biodigestora aplicado como biofertilizante para cultivo de palma forrageira (Opuntia ficus-indica) no semiárido brasileiro.

Abstract

The lack of access to adequate sanitation services in Brazilian rural regions presents a rate approaching 80% with almost 5 million Brazilians without any type of sanitary structure, leaving their waste in artisanal septic tanks. In this context, the application of wastewater reuse strategies has been a relevant option due to its low implementation and maintenance costs. Therefore, the effluent resulting from Biodigester Septic Tanks (FSB) installed in a rural residence in the municipality of Boa Vista-PB, located in the Brazilian semi-arid region (SAB), would present the appropriate physical-chemical and biological conditions for palm cultivation. forage on that property? The development of social technologies that strengthen the face of adverse weather conditions becomes a vital strategy for the survival of SAB communities. In this context, the reuse of wastewater through FSB constitutes a real and sustainable possibility both for the irrigation of family farming in the SAB region and for the protection of the environment. The general objective of the research was to evaluate the water quality of the effluent from a biodigester septic tank (FSB) installed in a rural residence in Sítio Bravo, municipality of Boa Vista-PB and its viability for the cultivation of the forage palm Opuntia ficus-indica ( L.). The present work is characterized as an exploratory, descriptive study of the analysis of FSB effluent installed in a rural residence. The system was composed of 04 water tanks, three of which were 1,000 L for the biodigestion process and one was 500 L for collecting, storing and distributing the effluent. The boxes were installed in 04 trenches 0.8m deep and 1.20m in diameter, interconnected with PVC pipes in the upper portion and final drainage in the lower portion. Seven serial effluent samples were collected between July 2022 and July 2023 and sent to the UFCG Desalination Reference Laboratory. (LABDES), after each collection, to analyze water quality parameters. Two experiments were isolated with 10 plants each, experiment A being the one that included the addition of biofertilizer, and experiment B which had no fertilizer added. To analyze the growth of Forage Palm, the number of rackets and height of plants in each experiment were measured. Both the values of the effluent water parameters and the values of the growth parameters were subjected to statistical treatment using SPSS 23 and JASP 0.14.6 software and subsequent analysis using the Wilcoxon and Mann Whitney methods. The effluent water parameters Color, Sodium and Electrical Conductivity were above the values recommended by CONAMA legislation; the other parameters were within normal limits according to current legislation and bibliographic findings, however, no relevant statistical variation was observed. Regarding Forage Palm, greater growth was statistically observed in experiment A, which included the addition of biofertilizer in relation to experiment B. The results alluded to the viability of the installed FSB with consequent benefit in the irrigation of Forage Palm of the species Opuntia ficus- indica (L.) Mill.) with growth in number of rackets and height of the plants analyzed. These results are promising in terms of benefits to the health, sanitation and social economy of the local community.