Key Laboratory of Agricultural Equipment in Mid-Lower Yangtze River, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, China.
Department of Agricultural Engineering, Faculty of Agriculture, Cairo University, Giza 12613, Egypt.
Int J Environ Res Public Health. 2019 Mar 19;16(6):996. doi: 10.3390/ijerph16060996.
Flocculation can remove large amounts of nitrogen and phosphorus from wastewater, and the resulting nitrogen- and phosphorus-rich floc can be used to produce organic fertilizer. For biogas slurries containing high levels of nitrogen and phosphorus, ordinary flocculants can no longer meet the flocculation requirements. In this study, to fully utilize the advantages of the two flocculants and achieve efficient removal rates of nitrogen and phosphorus from a biogas slurry, chitosan (CTS) and polyaluminum chloride (PAC) were used as a composite flocculation agent to flocculate pig biogas slurries. The response surface method was used to study the effect of PAC added (PAC) to the composite flocculant (CF), composite flocculant added (CF) to the biogas slurry and the pH on flocculation performance, and optimize these three parameters. In the tests, when the PAC was 6.79 g·100 mL, the CF was 20.05 mL·L biogas slurry and the pH was 7.50, the flocculation performance was the best, with an absorbance of 0.132 at a wavelength of 420 nm. The total phosphorus (TP) concentration was reduced from 214.10 mg·L to 1.38 mg·L for a removal rate of 99.4%. The total ammonia nitrogen (TAN) concentration was reduced from 1568.25 mg·L to 150.27 mg·L for a removal rate of 90.4%. The results showed that the CF could form larger flocs, and had greater adsorption capacity and more stable flocculation performance than ordinary flocculants. Furthermore, the CF could exhibit better chelation, electrical neutralization and bridge adsorption.
絮凝可以去除废水中大量的氮和磷，得到的富氮磷絮凝物可用于生产有机肥。对于含氮磷量高的沼气泥浆，普通絮凝剂已不能满足絮凝要求。在这项研究中，为了充分利用两种絮凝剂的优势，实现沼气泥浆中氮磷的高效去除，采用壳聚糖（CTS）和聚合氯化铝（PAC）作为复合絮凝剂对猪沼气泥浆进行絮凝。采用响应面法研究了 PAC 加入量（PAC）、复合絮凝剂加入量（CF）和 pH 对絮凝性能的影响，并对这三个参数进行了优化。试验中，当 PAC 为 6.79 g·100 mL，CF 为 20.05 mL·L 沼气泥浆，pH 为 7.50 时，絮凝性能最佳，在波长 420 nm 处吸光度为 0.132。总磷（TP）浓度从 214.10 mg·L 降低到 1.38 mg·L，去除率为 99.4%。总氨氮（TAN）浓度从 1568.25 mg·L 降低到 150.27 mg·L，去除率为 90.4%。结果表明，CF 可以形成更大的絮体，比普通絮凝剂具有更大的吸附能力和更稳定的絮凝性能。此外，CF 可以表现出更好的螯合、电中和和桥接吸附作用。
Zotero 插件