Jin Peng-Kang, Yang Zhen-Rui, Li Rong, Li Yan, Zhou Li-Hui
School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
Baotou Financial Investment and Assessment Center, Baotou 014030, China.
Huan Jing Ke Xue. 2017 May 8;38(5):1982-1990. doi: 10.13227/j.hjkx.201611097.
In this study, a set of two-stage UASB reactor was used to study the characteristics of denitrification inhibiting sulfate reduction in oil field gathering and transportation system and some high salt wastewater, and the characteristics of granular sludge and microbial characteristics were studied after the stable operation of the process. The results showed that the addition of NaNO increased the number of denitrifying bacteria (DNB) from 7.0×10 CFU·(100 mL) to 7.3×10 CFU·(100 mL) and remained stable in the process from start to mature. The competitive inhibition caused by DNB decreased the number of SRB from 8.0×10 CFU·(100 mL) to 7.6×10 CFU·(100 mL). Meanwhile, the sulfate reduction was inhibited, and the inhibition rate increased and finally stabilized to 82%. The study on mass ratio of microbial mass to nitrite effecting on denitrification efficiency showed that the inhibition rate of S was the highest, reaching 92%, when the mass ratio was 1200. The inhibition rate of the process could remain at about 92%, with good stability. The particle size and sedimentation rate of granular sludge were measured to determine whether the process conditions were favorable for the formation of granular sludge. The study showed that the denitrifying granular sludge formed was brown, basically ellipsoidal and spherical, with smooth surface and high density. Before the denitrification inhibition, the particle size of granular sludge was 1.0-1.4 mm and the average diameter was 1.17 mm, and after denitrification inhibition, the particle size distribution was 1.2-1.6 mm, the average particle size was 1.21 mm, which indicated that the denitrification inhibition increased the size of granular sludge. The average sedimentation velocity of denitrifying granular sludge was 47.6 m·h, which revealed the good settling performance of the granular sludge. The results of PCR-DGGE analysis showed that the denitrification inhibition reduced the number of microbial species from 18 to 14 and the number of dominant species decreased from 4 to 3, indicating the decreasing microbial diversity. The similarity of microbial population before and after nitrification was 62.6% and the population structure changed greatly from SRB to DNB. The number of dominant SRB species decreased from 4 to 2 after denitrification inhibition and the abundance of every species decreased obviously. The main functional bacterial species of the inhibition process was uncultured sp., which is a kind of autotrophic denitrifying bacteria. It dominated and competed with SRB for electrons, inhibiting the sulfate reduction and the production of sulfide.
本研究采用一套两级UASB反应器，研究油田集输系统及部分高盐废水反硝化抑制硫酸盐还原的特性，并在该工艺稳定运行后研究颗粒污泥特性和微生物特性。结果表明，添加NaNO后，反硝化细菌（DNB）数量从7.0×10 CFU·(100 mL)增加到7.3×10 CFU·(100 mL)，且在从启动到成熟的过程中保持稳定。DNB引起的竞争抑制使硫酸盐还原菌（SRB）数量从8.0×10 CFU·(100 mL)降至7.6×10 CFU·(100 mL)。同时，硫酸盐还原受到抑制，抑制率上升并最终稳定在82%。对微生物量与亚硝酸盐质量比对反硝化效率影响的研究表明，当质量比为1200时，S的抑制率最高，达到92%。该工艺的抑制率可保持在92%左右，稳定性良好。测量颗粒污泥的粒径和沉降速率，以确定工艺条件是否有利于颗粒污泥的形成。研究表明，形成的反硝化颗粒污泥呈褐色，基本为椭圆形和球形，表面光滑且密度高。反硝化抑制前，颗粒污泥粒径为1.0 - 1.4 mm，平均直径为1.17 mm，反硝化抑制后，粒径分布为1.2 - 1.6 mm，平均粒径为1.21 mm，这表明反硝化抑制增加了颗粒污泥的尺寸。反硝化颗粒污泥的平均沉降速度为47.6 m·h，这表明颗粒污泥具有良好的沉降性能。PCR - DGGE分析结果表明，反硝化抑制使微生物种类数量从18种减少到14种，优势种数量从4种减少到3种，表明微生物多样性降低。硝化前后微生物种群的相似性为62.6%，种群结构从SRB到DNB发生了很大变化。反硝化抑制后，优势SRB种类数量从4种减少到2种，每种的丰度明显下降。抑制过程的主要功能细菌种类为未培养的sp.，它是一种自养反硝化细菌。它占据主导地位并与SRB竞争电子，抑制硫酸盐还原和硫化物的产生。
