煤层气采出水达标排放处理技术研究

Research on the Treatment Technology for Standard Emissions of Coalbed Methane Produced Water

以鄂东区块采出水为研究对象,在对其水质特征充分分析的基础上,研究提出了“固定化微生物”曝气生物滤池的采出水COD和NH3-N的去除工艺,开展了3个阶段的现场试验进行COD和NH3-N去除效果的验证,同时采用GC-MS分析方法探究采出水中有机物氧化降解情况。试验数据显示:最终出水的COD、NH3-N均低于40,2 mg/L排放指标要求,难降解有机物种类和数量大幅减少。其中,COD去除率从70%逐步提升至80%,且随水力停留时间(HRT)增加而不断提升;NH3-N去除率可稳定达到99%以上,远低于标准设定值2 mg/L,且对HRT的调整不敏感。研究结果表明,以“固定化微生物-曝气生物滤池+活性炭吸附”为主体的工艺的处理技术,对鄂东区块采出水中的COD,NH3-N和难降解有机物均具有明显的去除效果,将HRT调整至8 h左右时,出水仍可稳定达标,此时的直接运行费用将降至1.40元/m^3以下,较化学处理工艺处理费用低70%以上,实现了鄂东区块煤层气采出水的“低成本、稳定达标排放”处理。

Taking the Ordos East edge produced water as the research object,based on the full analysis of its water quality characteristics,the research put forward a kind of biochemical removal process of COD and NH3-N,the process is focus on immobilized biological aerated filter(I-BAF).Carried out field test in three stages to verify the organic pollutant’s removal effect,such as COD and NH3-N,and explored their oxidative degradation state in the produced water with the aid of GC-MS analysis methods.Experimental data showed that the final effluent’s test values were lower than and target values(COD≤40 mg/L,NH3-N≤2 mg/L),and the type and quantity of refractory organic matters were sharply reduced.Among them,COD removal ratio increased from 70%to 80%and would continue to increase with the increasing of hydraulic retention time(HRT);NH3-N removal ratio was above 99%,far below the target values of 2 mg/L,and wasn’t sensitive to the adjustment of the HRT.The results showed that the process dominated by“I-BAF+activated charcoal adsorption”has obvious removal effect on COD,NH3-N and refractory organic compounds from the Ordos east edge produced water.If HRT was set for 8 h,the effluent can still meet the standard stably and the direct operation cost would drop below 1.40 yuan per cubic meter,which was more than 70%lower than that of the chemical treatment process,so the goal that“low cost,stable standardized discharge”of produced water treatment achieved.