Suitability of sugarcane stillage for the reuse in agriculture: assessment of different treatment technologies and potential environmental impacts

Author(s)

Isabella Junqueira Rodrigues

• Document type: Master's Dissertation
• Press: Rio Claro. 2016-09-23.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Geociências e Ciências Exatas. Rio Claro
• Defense date: 2016-07-22
• Advisor: Marcelo Loureiro Garcia

Abstract

Coagulation-flocculation processes emerge as an alternative to the post-treatment of effluent streams from anaerobic reactors, usually characterized by residual organic matter and color. This study aimed to adjust the best coagulation, rapid mixing, flocculation and sedimentation parameters applied to anaerobically treated vinasse and thus check whether the final effluent allows reuse, with emphasis on agricultural application. Solutions of starch 2% (m/v) and ferric chloride 40% were tested as coagulants, with dosages ranging from 1 to 120 mg.L-1 and 1 to 25 g.L-1, respectively. For the conditions tested, the results indicated the ineffectiveness of the starch solution as a coagulant for this effluent. For the tests performed with ferric chloride as coagulant, the optimal parameters were: ferric chloride solution dosage 40% (1.6 g.L-1), rapid mixing gradient and time (325 rpm, 10 s), flocculation gradient and time (65 rpm; 20 min) and settling time (20 min). Among the parameters, only coagulant dosage and settling time significantly (α=5%) impacted the performance of the process. The correction of the influent pH was not satisfactory for the performance of treatment. The results indicated that the coagulation/flocculation processes are most effective when applied to methanized compared to acidified and raw vinasses. From the results obtained, analyses were performed to verify the possibility of reuse of treated effluent in fertigation, observing that higher volumes of treated vinasse can be applied to the soil, as compared to raw vinasse. (AU)

• FAPESP's process: 14/04636-0 - Suitability of sugarcane stillage for the reuse in agriculture: assessment of different treatment technologies and potential environmental impacts
• Grantee: Isabella Junqueira Rodrigues
• Support Opportunities: Scholarships in Brazil - Master