Treatment of pulp and paper bleaching effluents by means of ozone advanced oxidation processes / Tratamento de efluentes do branqueamento da polpa celulósica por processos oxidativos avançados baseados em ozônio

AUTOR(ES)

Daniel Reis Medeiros

DATA DE PUBLICAÇÃO

2008

RESUMO

The impact of ozone oxidation in transforming high molecular weight (HMW) organic compounds in order to improve the biodegradability of pulp and paper effluents was investigated under different ozone doses. The experiments were conducted uppon a primary treated effluent and an alkaline bleach plant effluent taken from two pulp mills. The effluents were investigated under different initial pH (7 and 12). Ozone was applied using a semi-batch reactor equipped with fine bubble diffuser. The results showed the potential for using ozone as a pre-treatment to the conventional biological process. Applying 0.70 mgO IND.3/mLww to the primary treated effluent enhanced the ratio of BOD5/COD was from 0.18 to 0.35 and decreased the colour by 87%. The ratio of BOD5/COD was increased from 0.07 to 0.15 (initial pH 12) and to 0.20 (initial pH 7) and colour was reduced by 44% after applying 0.80 mgO IND.3/mLww to the alkaline bleach effluent from Howe Sounds mill. A similar behavior was observed after 0.80 mgO IND.3/mLww was applied to the alkaline bleach effluent from Catalysts mill. The ratio of BOD5/COD was increased from 0.07 to 0.16 and the effluent colour decreased by 78%. These changes were primarily driven by reductions of the HMW fractions of the effluent during ozonation. Organics with molecular range higher than 2 kDa were completely removed from the primary treated effluent. Aproximately 85% and 61% of the organics higher than 5 kDa were removed from the Howe Sounds alkaline bleach effluent under initial pH 7 and 12, respectively, after applying 0.72 mgO IND.3/mLww. Organic compounds with molecular weight higher than 10 kDa were completely removed from the Catalysts alkaline bleach effluent after applying 0.80 mgO IND.3/mLww. Molecular ozone available under neutral conditions seems to play an important role when the removal of the high molecular weight organic compounds is the main objective.

ASSUNTO(S)

effluents efluentes bleaching celulose molecular mass processos oxidativos avançados advanced oxidation processes biodegradabilidade biodegradability distribuição da massa molecular recalcitrancy recalcitrância ozônio ozone branqueamento molecular weight distribution

Documentos Relacionados

• Anaerobic process conjugated with advanced oxidation processes (AOP) for the treatment of the bleaching effluents from a kraft pulp mill
• Tratamento de efluentes contendo fenol através de processos oxidativos avançados (POAs).
• Degradação de abamectina por processos oxidativos avançados
• Combinação de tratamento biológico aeróbio com processos oxidativos avançados visando intensificar a remoção de matéria orgânica em efluentes da indústria têxtil e de celulose kraft
• Tratamento de efluentes industriais por processos oxidativos na presença de ozônio