厌氧消化液不同投加方式对AOA-SBR系统处理效果的影响

为研究厌氧消化液的不同投加方式对AOA-SBR(厌氧/好氧/缺氧序批式反应器)系统处理效果的影响,在温度为20.0 ℃、生活污水与厌氧消化液体积比为24∶1、污泥中AOB(氨氧化菌)所占比例为7.34%条件下,考察了不投加、厌氧阶段开始一次性投加、好氧阶段开始一次性投加和好氧阶段分次投加等6种厌氧消化液投加方式(分别记为SBR-a、SBR-b、SBR-c、SBR-d、SBR-e、SBR-f)下AOA-SBR系统中SCOD_Cr(溶解性化学需氧量)、PO₄3--P、NH₄+-N的处理特性. 结果表明:厌氧消化液的投加方式对SCOD_Cr的去除基本没有影响,但厌氧消化液的投加使系统中PLR(PO₄3--P进水容积负荷)提高了104.88%,导致除SBR-a外各试验组出水ρ(PO₄3--P)均大于2.0 mg/L,为AOA-SBR处理生活污水与厌氧消化液联合废水的主要限制因素. SBR-b~SBR-f的SNPR(比亚硝酸盐生成速率)均高于SBR-a,表明厌氧消化液的添加有助于稳定污水短程硝化. 研究显示,厌氧开始阶段一次投加厌氧消化液(SBR-b)对系统脱氮效果影响最小,为最佳进水方式,此时SAUR(比氨氧化速率)为0.168 0 g/(g·d),SNPR(比亚硝酸盐产生速率)为0.136 3 g/(g·d),SND(同步硝化反硝化)作用率为26.64%. 

Effects of Different Feeding Modes of Anaerobic Digestion Supernatant on AOA-SBR Efficacy

The effects of six feeding modes in treating anaerobic digester (AD) supernatant and domestic sewage were investigated using shortcut nitrification sequencing batch reactor (SBR) by anaerobic-aerobic-anoxic (AOA) processes. Batch experiments were incubated at 20.0 ℃ in domestic sewage-AD supernatant (24∶1) media, and the ratio of ammonia oxidizing bacteria (AOB) was 7.34%. AD supernatant was injected at the beginning of the anaerobic or aerobic phase and dosed two or three times during the aerobic phase, hereafter referred to as SBR-a, SBR-b, SBR-c, SBR-d, SBR-e and SBR-f. Soluble chemical oxygen demand (SCOD_Cr), PO₄3--P and NH₄+-N concentrations were also determined in the present study. The results showed that adding AD supernatant had no effect on removal of organic matter at various feeding modes. However, removal of PO₄3--P was low when AD supernatant was treated in AOA-SBR combined with domestic sewage. In fact, phosphate loading rate (PLR) increased by 104.88%. Concentrations of PO₄3--P in the effluents were also higher than 2.0 mg/L in all experimental conditions, which could have been the limitation of the AOA-SBR system. Specific nitrite production rate (SNPR) in dosing AD supernatant was significantly higher than that of AOA-SBR, but only in the treatment of domestic sewage, which indicated that the addition of AD supernatant helped stabilize shortcut nitrification. Adding AD supernatant at the beginning of the anaerobic phase in AOA-SBR attained the best results, with increases in specific ammonia uptake rate (SAUR) (0.1680 g/(g·d)), SNPR (0.1363 g/(g·d)), and simultaneous nitrification denitrification (SND) rate to 26.64 %.