猪粪中温厌氧消化中磺胺类抗生素的降解和吸附特征

针对猪粪厌氧消化中磺胺类抗生素(SAs)去除途径及降解规律不明晰等问题,采用批次室内模拟发酵试验方法,探讨磺胺嘧啶(SDZ)和磺胺二甲嘧啶(SM2)在中温(37±1℃)厌氧消化条件下的吸附和降解特征及规律。结果表明:在SDZ和SM2添加量均为20 mg·L-1时,发酵结束后二者的去除率分别为58.7%和74.0%,符合一级动力学模型,降解半衰期分别为5.85、5.90 d。在中温厌氧消化系统中,SDZ和SM2首先发生快速吸附作用而固定在固相中,前4 h吸附较快,至12 h时达到吸附平衡;随后发生较为缓慢的生物降解作用,至24 h后生物降解成为SDZ和SM2去除的主要途径,占其去除总量的80%以上。SAs与易分解有机物的共代谢作用是影响其生物降解的关键因素。

The degradation and adsorption of sulfonamides in mesophilic anaerobic digestion of swine manure

Concentrated animal feeding operations(CAFOs)are considered to be point sources of sulfonamide(SAs)pollution. Anaerobic digestion(AD)is used to treat manure and wastewater from CAFOs, reducing contamination and producing renewable energy and bio-fer-tilizer. However, little is known about how the AD process affects SAs. In this study, bench-scale batch experiments were conducted to in-vestigate the biodegradation and adsorption characteristics of sulfadiazine(SDZ)and sulfamethazine(SM2)via AD of swine manure un-der mesophilic conditions(37±1)℃]. The removal rates of SDZ and SM2 were 58.7％and 74.0％, respectively, at initial concentrations of 20 mg·L-1. The first-order model best fit SDZ and SM2 removal dynamics, with degradation half-lives of 5.85 d and 5.90 d, respectively. Adsorption was rapid early in the AD process;SDZ and SM2 were adsorbed rapidly on solid digestates within 4 h and reached adsorption e-quilibrium within 12 h. After this point, slow biodegradation occurred, and was the dominant SDZ and SM2 removal pathway after 24 h. The removal rate through biodegradation reached>80％for both SAs. SAs removal was significantly correlated with the soluble chemical oxygen demand(SCOD), indicating that degradable organic matter was co-metabolized during SAs removal during AD of swine manure.