高浓度乙二醇气田废水厌氧生化处理试验研究

天然气输送过程中,通常注入乙二醇,以抑制水合物产生。由于回收时分离不完全,部分乙二醇与产出水混合,形成高浓度乙二醇气田废水。对于这类废水的处理,现有方法实际应用效果均不理想,在文献调研和分析的基础上,提出采用厌氧生化法处理。试验采用自行设计的厌氧生化反应器,整个试验过程依次为厌氧微生物适应阶段、提高负荷阶段、稳定运行阶段。试验结果显示:厌氧活性污泥对乙二醇气田废水的适应期为3d,经过20d的连续提高负荷,使最终负荷达到约12kg COD/(m3·d),稳定运行阶段进水COD浓度为13000mg/L,HRT控制在24h,稳定运行后出水COD在1000mg/L以下;进水COD浓度高于10000mg/L时,提高其p H值到7.4~7.5,可以保证厌氧效果不受影响。这表明,厌氧生化法处理含高浓度乙二醇气田废水是可行的。

The Experiments on Anaerobic Biotreatment of High-concentration Glycol Gas Field Wastewater

Glycol is injected to prevent the production of gas hydrate in gas pipelines. Due to incomplete separation when recovered,part of the glycol is mixed into the water produced and this is where gas field wastewater with high concentration of glycol comes from.All existing methods for treating such wastewater are unsatisfactory when in actual use.Based on literature study and analysis,researchers proposed to treat such wastewater using an anaerobic biochemical method.In an experiment,a domestically designed anaerobic biochemical reactor was used.The entire experiment consisted of an anaerobic microbe adaptation phase,a load increasing phase and a stable operation phase.Experimental results show that the period when anaerobic acti-vated sludge get adapted to glycol-containing gas field wastewater is three days.The experimental load was increased in 20 consecutive days and eventually reached about 12 kg COD/（m3·d）.The COD concentration of the feedwater in the stable operation phase was 13000mg/L and HRT was maintained at 24 h.The COD concentration of the water produced after stabilization of operation was below 1000mg/L.When the COD concentratin of feedwater is higher than 10000mg/L,the pH of the feedwater can be raised to 7.4-7.5 and the anaerobic effect will not be affected.The results suggest that using the anaerobic biochemical method to treat gas field wastewater with high concentrations of glycol is feasible.