| At present, most of the oilfields in china increasing year by year and the efflux of the production waste water becomes more and more. The problem of oilfield wastewater discharging below standard has become one of the factors constraining the sustainable development of oilfields. And the cost high affects the application of treatment. The urgent issue of oilfield is how to reduce the contamination of oilfield wastewater economically and effectively.Because the fly ash has features of alkalescency and sorption,The author proposed the pretreatment of oilfield wastewater by fly ash and could reduce the contamination availably and achieve muti-use of waste.It studies the dynamics of oilfield waste water treatment by fly ash and find out the mechanism of oilfield treatment by fly ash in this paper. Through the experiment of adsorption in lab and mechanical stirring, we researched the rule and effect of oil COD volatile phenol NH3-N adsorption in oilfield wastewater by fly ash and protract the adsorption isotherm. After that, we researched the degradation function of organic matter on fly ash by animalcule and the midsplit rule in ash of animalcule. It provides the basis for the experiment program and the determination of operating parameters.Through experiments and researches, we identified the better working condition parameters of gray-water ratio, stirring time, stirring intensity, pH value Etc. which achieve the greatest ability to deal with fly ash(are): fly ash mixtured with the ash-water first and then mixed with the produced water: Fly Ash (g): ash-water (mL): produced water (mL) was 1:20:50, stirring 15min, 200r/min, do not change the pH value of former water. In this case, the removal rates of oil in the wastewater, COD, and volatile phenol that removed by fly cash are 80%, 20% and 10% respectively. The adsorption capacity of oil and COD is 0.91mg / g and 1.34mg / g respectively, The absorption of Ammonia is negative.The experiment shows that: With the increasing of produced water, the biggest adsorption of COD and oil which was adsorpted by fly ash in SL power plant is 10.1mg / g and 1.4 mg / g respectively. The experimental results show that : the better operating parameters to remove COD in oil wastewater is adsorped by fly ash ,which is mixed with produced water(,is): ash (g) Water (mL) ratio is 1:30, pH=10, temperature of 35℃,shaking 48h, 120r/min; the average of COD adsorption capacity is 1.0mg / g, and COD removal rate reaches 40%. It leads to COD adsorption isotherm jumping like. Because fly ash and produced water are multi-component system, which has a variety of solid-liquid interface adsorption.Tests showed that the treatment of fly ash that mixed with the ash-water first and then with oil produced water is better than that mixed with produced water directly.According to the experimental results, after improving the treatment process parameters of the "Fly + oxidation pond project" in Xianhe oil waste water, the processing load increased from the 10000 Cubic meters / day to 22,000 Cubic meters / day, One-year's running shows that it runs well, and has a obvious economic benefits, water quality can stably reach the "Shandong Peninsula General Basin water pollutant discharge standard" requirements.Studies have shown that the project has taken the anti-seepage measures, and also has reduced the local conditions of soil salinization to a certain extent. The operation has some influences on the surrounding groundwater but has no influences on the surface water around.According to analysis of the feature of fly ash which is used to treat produced water, the produced water has no effect on the leaching toxicity of fly ash and reuse of channels. After the fly cash which was used to treat produced water is piled up and the water is leaked at storage yard , it can be used as "fly ash sintered hollow block", "mixed a small amount of ordinary fly ash cement hollow block", "backfilling works" and "roads Project "of raw materials for reuse. |
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