• DOI:10.2166/wst.2012.476
• Corpus ID: 43319068

Application of urea dosing for alkalinity supply during anaerobic digestion of vinasse.

@article{Boncz2012ApplicationOU,
  title={Application of urea dosing for alkalinity supply during anaerobic digestion of vinasse.},
  author={Marc A. Boncz and Edin{\'e}ia Lazarotto Formagini and L. da S. Santos and Rodrigo Domiciano Marques and Paula Loureiro Paulo},
  journal={Water science and technology : a journal of the International Association on Water Pollution Research},
  year={2012},
  volume={66 11},
  pages={
          2453-60
        }
}

• M. A. Boncz, E. L. Formagini, +2 authors P. L. Paulo
• Published 1 October 2012
• Engineering
• Water science and technology : a journal of the International Association on Water Pollution Research

Pushed by demand for renewable energy, the ethanol industry in Brazil is expanding. However, production of 1 m(3) of ethanol generates around 13 m(3) of liquid residues (vinasse), so this expansion results in an increasing need for a more adequate destination of these residues. Nowadays the vinasse is dispersed on the sugar cane fields in the practice of fertirrigation, but anaerobic digestion of this residue may be a better solution, additionally offering an alternative source of energy, able to complement hydroelectric power supply in the dry season. However, when trying to digest vinasse at reduced hydraulic retention times, complications arise from its strong tendency toward acidification, upsetting the fragile balance of transformations normally occurring under anaerobic conditions. For successful operation of an anaerobic treatment process with acceptable hydraulic residence times, increasing alkalinity levels inside the reactor is neces-sary. In the present work we show that pH regulation by means of urea dosing, in spite of the risk posed by ammonia toxicity towards methanogenic biomass, can be a viable alternative to avoid vinasse acidification. The ammonia formed in urea conversion remains in solution, rather than escaping to the biogas, and so its use as fertiliser can offset its cost of application in the process.