The effect of fertirrigation of treated domestics sewages over sanitary quality and okra productivity

Abstract

In an attempt to find a technique with low risk of disease transmission and high productivity, the objective of this work was the analysis of the performance of sewage treatment systems, evaluating the microbiological and parasithological effluent quality and verifying the effect of their use on irrigation through productivity evaluation and contamination in the cultivation of okra (Abelmoschus esculentus). Effluent from UASB reactor and its post-treatment in a Polishing Pond and Biological Filter were used. The effect of fertirrigation on okra productivity was compared to productivities obtained when crops were irrigated with supply water and when soil were treated with mineral fertilizer. Verification showed that effluent from UASB reactor and the Biological Filter effluents presented results that did not comply with WHO sanitary recommendations, but its posttreatment in a Polishing Pond provided an effluent which did not present helminth eggs and showed a concentration of thermotolerant coliforms below 1.000UFC/100mL. The fertirrigation of cultivations of okra with effluent from Biological Filter and UASB effluent led considerable productivity (25,7 and 24,7 t/ha), but didn’t show a significant difference when compared to okra, which received mineral fertilizer (27,8t/ha). Concluing, is feasible fertirrigation with treated domestic sewage in the semiarid regions, but is necessery to maintain a microbiological and parasitological control periodically.

Key words:
residual waters; treatment; reuse; fertirrigation