CHEMICAL PROCESS FOLLOWED BY ACTIVATED SLUDGE TREATMENT OF COTTON PULPING EFFLUENTS FOR NITROCELLULOSE PRODUCTION

L. F. Santos, F.T. Silva, T.C.B. Paiva

Abstract: The present research work aims to characterize cotton pulping effluents (black liquor and washing waters) for producing nitrocellulose to be used in explosives manufacture. After characterization, equal portions of the effluent samples were mixed, thereby forming a homogeneous mixture called as the pulping effluent which was treated by a chemical process followed by the activated sludge biological treatment. The main results of the pulping effluent initial characterization were: pH at 12.4, 28,530 UC color, 7,797 mg/L COD, 4,399 mg/L BOD, 2,455 mg/L TOC, 9,269 mg/L TSS, 4,035mg/L TFS and 5,234mg/L TVS. The chemical treatment consisted in acidifying the pulping effluent with an acid effluent from the stage of cellulose nitration until reaching pH=1.5 + 0.3, which allowed coagulating/decanting a large amount of the organic materials in the sample. After pH was adjusted to 7 + 0.2, the chemically treated effluent was submitted to the activated sludge treatment in a 500L reactor in a semi-continuous process. The chemical process integration with the activated sludge treatment allowed reducing color by 95.8%, COD by 96.4%, BOD by 99%, TOC by 97.8%, TSS by 96.9%, TFS by 95.8% and TVS by 97.8%. The obtained results from the scale-up showed that these processes integration was effective at treating the cotton pulping effluents, thus confirming the results obtained on smaller scales.

Keywords: Effluent, Treatment, Cotton, Black Liquor

DOI: https://doi.org/10.15623/ijret.2017.0605006