改良型SBR工艺对奶牛场废水中抗生素的去除效果

Removal of Antibiotics from Dairy Farm Wastewater by Modified SBR Process

奶牛场废水中的有机物和抗生素对其还田利用不利,为此,采用带缺氧区的推流式SBR(简称改良型SBR)工艺处理干清粪条件下间歇产生的奶牛场废水,重点考察其对抗生素的去除效果。结果表明,当进水COD、NH4+-N、TN、TP浓度分别为1 234~4 696、768~1 365、880~1 370、5.62~12.02 mg/L时,经改良型SBR工艺处理后,出水COD可降至401~544 mg/L、NH4+-N始终低于10mg/L,TN平均损失率为22.38%,TP基本没有被去除。奶牛场废水中磺胺类和β-内酰胺类抗生素总浓度为3.84~4.48μg/L,改良型SBR工艺对其总去除率可达到72.97%~90.82%,且对10种较高浓度的磺胺类抗生素(每种添加浓度均为50μg/L,共计500μg/L)也有很好的去除效果,去除率可达95.75%~95.97%。生物降解是奶牛场废水中磺胺类和β-内酰胺类抗生素的主要去除途径,另外,磺胺类抗生素的去除与其分子结构中S—N键的断裂有重要关系。在不影响COD去除效果的条件下,调整反应器的混合液回流量或进水量均可减少碱度投加量,从而降低运行成本。

Organic matter and antibiotics in dairy farm wastewater are detrimental to their return to the field.Therefore,a modified SBR(plug-flow SBR) process with anoxic zone was applied to treat the dairy farm wastewater produced intermittently under the condition of dry manure cleaning,and the removal of antibiotics by the process was investigated.When COD,NH4+-N,TN and TP concentrations in the influent were 1 234-4 696 mg/L,768-1 365 mg/L,880-1 370 mg/L and 5.62-12.02 mg/L respectively,after treatment by modified SBR process,the effluent COD was decreased to 401-544 mg/L,the effluent NH4+-N was always less than 10 mg/L,the average loss rate of TN was 22.38%,and TP was basically not removed.The total concentration of sulfonamide and β-lactam antibiotics in the dairy farm wastewater ranged from 3.84 μg/L to 4.48 μg/L,and the total removal efficiency of the two kinds of antibiotics by the modified SBR process reached 72.97%-90.82%.The modified SBR process also had good removal performances to 10 kinds of sulfonamide antibiotics with high concentrations(50 μg/L for each,500 μg/L in total),and the removal efficiency reached 95.75%-95.97%.Biodegradation was the main pathway to remove sulfonamide and β-lactam antibiotics from dairy farm wastewater.In addition,the removal of sulfonamide antibiotics had an important relationship with the breaking of S—N bonds in their molecular structure.Under the condition that COD removal was not affected,the dosage of alkalinity could be reduced by adjusting the return flow of mixed liquid or the inflow of the reactor,thus reducing the operational cost.