| Semi-synthetic antibiotics wastewater has complex composition and highconcentration of COD, BOD5, salts and antibiotics, the biodegradability ofwastewater is rather low, and the effect of conventional biological treatment isunsatisfactory,therefore, it is essential to take on appropriate pretreatment for thiswastewater. In this paper, taking clindamycin phosphate and other semi-syntheticantibiotics wastewater as the research object, in view of its specific characteristics,the pretreatment method of chemical phosphorus removal-Fe2+/K2S2O8oxidationwas raised by the author.The optimum flocculant and dosage was determined by thetest of chemical phosphorus removal; the optimum reaction conditions for theFe2+/K2S2O8oxidation was dertermined by the orthogonal test and further singlefactor test; the variation of wastewater biodegradability after the oxidation wasanalyzed by anaerobic gas production test; the qualitative research about·SO4-and·OH was carried out to explore the mechanism of Fe2+/K2S2O8oxidation; thecomparative test of Fe2+/K2S2O8oxidation and Fenton oxidation was conducted,furthermore, the integratation of heterogeneous technology and Fe2+/K2S2O8oxidation was utilized to optimize the treatment effect of the oxidation.By comparing the phosphorus removal effect of PFS, PFC, PAC, PAFC, CaO, itwas confirmed that CaO was the optimum flocculant, better than aluminouscoagulants and ferrous coagulants, which was significantly influenced by thereaction pH, the chroma of effluent after ferrous coagulants treatment grew bad, theeffect of PFS was better than PFC; the effect of PAFC was better than PAC; whenthe dosage of CaO was2000mg/L, the TP of effluent reduced to5.4mg/L, TPremoval efficiency reached97.3%at the moment. It was determined that CaO was choosed as the optimum flocculant and the optimum dosage was1800mg/L, underthis condition, the TP of effluent reached to10mg/L or less, which almosteliminated the influence of phosphate on Fe2+in the subsequent process, the pH ofeffluent nearly rose to12, which not only improved the stability of the generatedsediment, but also achieved the conditions of antibiotics alkaline hydrolysis (pH>11),the combination of alkaline hydrolysis and coagulation effectively reduced theantibiotics titer and the difficulty of the subsequent oxidation reaction.A series of studies about Fe2+/K2S2O8oxidation showed that the optimumconditions of Fe2+/K2S2O8oxidation for the phosphorus removal effluent were that:FeSO4and K2S2O8dosage was1.3mmol/L and0.7mmol/L, reaction time was50min,the initial pH was7.0, under the optimum conditions, the COD and chroma removalcould reach63.4%and62.5%respectively; the biodegradability of the wastewaterafter oxidation had been greatly improced and the efficiency of the subsequentbiological treatment would get enhanced in a large degree; the Fe2+/K2S2O8oxidation could efficiently deal with the alkaline semi-synthetic antibioticswastewater, it was the result of synergy among·SO4-,·OH and other activesubstances; it was more suitable in acidic conditions for Fenton oxidation, however,Fe2+/K2S2O8oxidation showed a certain advantage in dealing with alkalinewastewater, furthermore, Fe2+/K2S2O8oxidation had smaller dosage, less sludge andlower cost; iron-carbon filler, pyrite cinder, magnetite, iron scraps and quartz sand,as solid mediums in the heterogeneous systems, could promote Fe2+/K2S2O8oxidation in different degrees, the effect of iron-carbon filler was best,and ironscraps was worst, after overall consideration, quartz sand was determined as thefinal solid mediums and the fluidized bed reactor was considered to applied to thesubsequent studies.This study, no matter in the field of the treatment for semi-synthetic antibiotics wastewater, or in the field of advanced oxidation technology, has certain innovationand engineering practicality. |
PDF Full Text Request