药剂联合高温对低有机质污泥水解促进研究

Effects of Chemical Agent Combined with High Temperature on Hydrolysis of Sludge with Low Organic Content

厌氧消化是实现污泥稳定和能源回收的主要途径之一。我国南方地区污水处理厂广泛采用生物营养物去除工艺,普遍存在进水有机物含量低的问题,导致污泥有机质含量也偏低(VS/TS<0.6)。针对南方典型低有机质污泥,在120℃、0.5 h条件下分别投加NaOH、Ca(OH)_(2)和CaCl_(2)进行联合高温热水解预处理后,进行中温厌氧消化。结果表明,投加药剂联合高温热水解促进了溶解性有机碳(SOC)、可溶糖、可溶性蛋白质的溶出,进而提高了累积产甲烷量。在高温热水解预处理过程中,药剂对有机物的溶出效果为NaOH>Ca(OH)_(2)>CaCl_(2)。在后续厌氧消化过程中,由于CaCl_(2)可提高SCOD中碳水化合物占比,投加CaCl_(2)联合高温热水解后总化学需氧量(TCOD)和总糖降解效果明显,TCOD降解量为25326 mg/L且总糖降解量在TCOD降解量中占比最高(87.7%),因而3种药剂中CaCl_(2)的累积产甲烷量最高(183.1 mL/gVS)。CaCl_(2)联合高温热水解预处理较NaOH、Ca(OH)_(2)更能提高低有机质污泥的厌氧产沼性能。

Anaerobic digestion is one of the main strategies to facilitate sludge stabilization and energy recovery. The biological nutrient removal process is widely applied in wastewater treatment plants in southern China, and the widespread low content of influent organic matter results in the low content of sludge organic matter(VS/TS < 0.6). In this paper, the typical sludge with low organic content in southern China was first pretreated with chemical agents including NaOH, Ca(OH)_(2)and CaCl_(2)combined with thermophilic hydrolysis at 120 ℃ for 0.5 h. Then, the sludge was used as the substrate for mesophilic anaerobic digestion. The addition of chemical agents combined with thermophilic hydrolysis promoted the release of soluble organic carbon(SOC), soluble sugar and soluble protein, and increased the cumulative methane production. In the process of thermophilic hydrolysis pretreatment, the efficiency of chemical agents for dissolution of organic matters in descending order was NaOH, Ca(OH)_(2)and CaCl_(2). In the subsequent anaerobic digestion process, since CaCl_(2)promoted the proportion of carbohydrates in SCOD,the degradation efficiencies of total chemical oxygen demand(TCOD) and total sugar were obviously improved after dosing CaCl_(2)combined with thermophilic hydrolysis. The degradation of TCOD was25 326 mg/L, and the degradation of total sugar accounted for the highest proportion of the degraded TCOD(87.7%), so the cumulative methane production of CaCl_(2)among the three agents was the highest(183.1 mL/gVS). The addition of CaCl_(2)combined with thermophilic hydrolysis pretreatment was more effective to enhance the anaerobic biogas production performance of low organic sludge than NaOH and Ca(OH)_(2).