废弃钻井液酸化-氧化-中和-生物降解组合处理工艺的实验研究

Laboratory Study on the Composite Treatment of Waste Drilling Fluids Using Acidification-Oxidation-Neutralization-Biodegradation

针对四川气田高浓度废钻井液,提出采用酸化破胶、固液分离、Fenton试剂氧化、CaO中和预处理和微生物降解组合工艺,使出水达到国家排放标准。实验表明,废钻井液酸化后的pH值小于5时,固液分离效果较好;初始pH值为3～4、H2O2加量为0.5～0.6mol/L、反应时间大于2.5h时,Fenton试剂催化氧化反应的处理效果最佳;利用CaO中和试剂的絮凝作用,能进一步降低CODCr值;在微生物降解处理中,活性污泥中的微生物经过筛选、驯化,可显著提高其对废水处理液中有机物的氧化分解能力和降解效率,出水CODCr值可稳定小于100mg/L。该组合处理工艺实现了废钻井液的无害化处理,具有运行成本低、处理彻底、无隐患等特点。

A waste drilling fluid treatment technique was presented to deal with the heavy waste drilling fluids from Sichuan gas field.The treatment included the following steps:breakdown by acidification,solids-liquid separation,oxidation by Fenton,Neutralization with CaO,and degradation by microorganism.The experimental results showed that good separation can be achieved when the pH value of the waste drilling fluid is less than 5.An optimum catalytic oxidation with Fenton can be obtained when:the initial pH value of the drilling fluid is 3～4,H2O2 concentration is 0.5～0.6 mol/L and the reaction time is longer than 2.5 hours.Flocculation with CaO can further reduce the CODCr value.In microorganism degradation reaction,the selected,cultured microorganism in the active sludge had a remarkably improved oxidation and degradation performance in the treatment of the organic wastes and the leachate had a stable CODCr value less than 100 mg/L.This water drilling fluid treatment technique can help achieve the real innocent treatment of waste drilling fluids and is cost effective.