Study On Drilling Wastewater By Acidification-microelectrolysis-fenton-coagulation

The drilling wastewater is a special kind of industrial wastewater produced in Oil&Gas drilling fields,whose quality characteristics are: complexity of component, high CODcr and chroma, suspended solids, many contains of oil component, heavy metal and high salinity. If the drilling wastewater is not disposed before it is discharged, it will be a great influence on the surrounding environment., especially farmland. It will form a film on the face of soil, which will prevent oxygen from entering, cause the crop die, and make the soil salinization-alkalization..This thesis makes a study on the effects of drilling wastewater treatment technology and the best conditions of acidification, ferric-carbon micro-electrolysis, Fenton reagents and coagulation. Orthogonal experiment is used to confirm optimum conditions of each process, and then put all processes into different orders to form different combinations, confirm the best combination and its'optimum reaction conditions. The optimum conditions of acidification, ferric-carbon micro-electrolysis, Fenton reagents and coagulation are respectively:â‘ Acidification experiment. pH2, reaction time 3h, and the removal efficiency of CODcr is 75.8%;â‘¡Ferric-carbon micro-electrolysis experiment. Fe(V):C(V)1, pH2, reaction time 3d, and the removal efficiency of CODcr is 78.9%;â‘¢Fenton reagents experiment. H2O2(mol):Fe2+(mol)9, pH3.5, reaction time 3h, and the removal efficiency of CODcr is 62.7%;â‘£Coagulation experiment. pH8, PAC100mg/l, PAM10 mg/l, reaction time 50min, and the removal efficiency of CODcr is 35.4%.Simultaneously, this thesis is also to explore acidification/Fenton reagents /ferric-carbon micro-electrolysis /neutralization/ effluent, acidification/ferric-carbon micro-electrolysis /Fenton reagents /neutralization/ effluent and acidification/ferric-carbon micro-electrolysis / coagulation /Fenton reagents /neutralization/ effluent, and confirm the best combination and its'optimum reaction conditions. The treatment effects of the three processes are: 1) Acidification/Fenton reagents /ferric-carbon micro-electrolysis /neutralization/ effluent. The removal efficiencies of CODcr, color index, SS and oil are respectively 97.5%, 95.5%, 98.1%, 97.5%; 2)Acidification/ferric-carbon micro-electrolysis /Fenton reagents /neutralization/ effluent. H2O2 11g/l. The removal efficiencies of CODcr, color index, SS and oil are respectively 98.2%, 96.6%, 98.8%, 97.6%.3) Acidification/ferric-carbon micro-electrolysis / coagulation /Fenton reagents /neutralization/ effluent. The removal efficiencies of CODcr, color index, SS and oil are respectively 95.7%, 94.6%, 97.5%, 96.5%. Acidification/ferric-carbon micro-electrolysis /Fenton reagents /neutralization/ effluent is the optimum in the three processes, its'process is simple, convenient and the drug dosage is easy to control. Ferric-carbon micro-electrolysis produces a large number of Fe2 + and Fe3 +, which can form Fe (OH) 2 and Fe (OH) 3 with NaOH. Fe (OH) 2 and Fe (OH) 3 are a kind of deposition, which have strong adsorption and flocculation activity. Fe2 + and Fe3 + make Fenton reagents with H2O2. So acidification/ferric-carbon micro-electrolysis /Fenton reagents /neutralization/ effluent have a higher value and popularization meaning.Additionally, the thesis selects the optimum combination acidification/ferric-carbon micro-electrolysis /Fenton reagents /neutralization/ effluent to apply to engineering. From the perspective of effect, the effluent is below to the Class A of Integrated Wastewater Discharge Standard(GB9878-1996),and it is feasible in technique. From the perspective of economy, the cost is 18-24 yuan/m3, and it is applicable in economy. To sum up, Acidification/ferric-carbon micro-electrolysis /Fenton reagents /neutralization/effluent is applicable in technology and economy.