The dewatering performance and mechanism of streptomycin mycelial residue based on Fenton oxidation

Streptomycin mycelial residue (SMR) derived from streptomycin production is a typical kind of antibiotic mycelial residue (AMR). Pyrolysis and incineration can completely conquer the troubles derived from the residual antibiotics and resistance gene during the recycling of antibiotic mycelial residue (AMR). However, the high-water content (usually >90 %) of AMR greatly limits the application of thermochemical method. In this work, an interesting and novel try on the dewatering of SMR through Fenton conditioning was conducted. The effects of operational parameters on SMR dewaterability, evaluated by the specific resistance to filtration (SRF) and water content (WC) of filter cake, were explored. Besides, comprehensive analyses on SMR were performed to reveal the dewatering mechanism. Increasing the dosage of H2O2 instead of Fe2+ was more favorable to improve oxidation capacity of Fenton system under the weak oxidizing condition. Both the strong-acid and the alkaline environments were detrimental to the function of Fenton's reagent. The SRF and WC of SMR can be reduced by 92.91 % and 20.12 % at the optimal condition of Fe2+=50 mg/g DS, H2O2= 60 mg/g DS, pH= 3.5, and reaction time= 60 min, respectively, which can give guidance on the industrial application of Fenton technique. The oxidation efficacy of Fenton's reagent was the crucial to improve the dewaterability of SMR, which can destroy flocs/mycelium cells to release the interstitial water/intracellular bound water and construct hydrophobic channels in flocs to facilitate the further water removal. Besides, the reforming and flocculation derived from Fenton's system can also contribute to SMR dewatering.