Study On The Treatment Of Oily Wastewater In The Loess-Microorganism System By Laboratory Simulation Experiments

Loess in Lanzhou and the wastewater from a chemical factory in XiGu was selected as research objects, basing on the chemical composition and physical properties analyzing of the soil sample and water sample, the removal effect of loess-microorganism system on oil pollution treatment and the influencing factors are studied by laboratory simulated experiments in this paper.Firstly, by studying the adsorption capacity of loess for mineral oils ,the adsorption mode of the loess of oily wastewater pollutants was identified, and the influence of temperature, pH, organic matter content and salt contents on the adsorption were investigated by laboratory static experiments. Then, the indigenous bacteria in loess were activated to reduce oil by supplementing nutrients and changing other ecological conditions to study the treatment effect of oil pollutant to oily wastewater in the Loess-microorganism system. The influencing factors such as nutrient substance, temperature, oxidizer and pH were researched, and the optimal ecological condition was determined through orthogonal experiment. Finally, using oil as the sole carbon source, get the dominant strain by repeated screening and separation of micro-organisms which in the Loess-microorganism system, and preliminary identification of them.The treatment effect of petroleum degradation bacteria on oily wastewater was determined and the experiment provides theoretical basis for the feasibility that loess - microbial system is utilized to treat oily wastewater. The following conclusions were draw through sorting out and analyzing the test results:(1) The static adsorption experiments indicate that Malan loess in Lanzhou region of oily waste water treatment effect is quite good. Through the static adsorption of malan loess experiments can be concluded that the unit of oily wastewater in loess oil natural adsorption quantity can reach 1086.07 mg/kg, The adsorption of oils on loess conforms to Langmuir isotherm;(2) The influencing factors experiments indicate that the adsorptive capacity drops from 1020.49mg/kg to 1104.51 mg/kg with the temperature elevating from 20℃to 45℃process; with the pH value elevating from 13 to 3, the adsorptive capacity drops from 1178.28 mg/kg to 998.95mg/kg; Adsorption tends to increase with the decrease of diameter of soil particles; There is a positive linear correlation between the adsorption and the organic matter content or salt contents. With the organic matter content and salt content increasing, the adsorption increase.(3) The loess-microorganism system simulation experiments indicate that the loess-microorganism system has buffer effect and self adjusting function; adequate nutrients and antioxidants can improve the microbial loess processing efficiency; the best ecological conditions of Loess-Microorganism System are as follows: nutrient proportion (C:N:P) is 500:6:1, temperature is 35℃, the accumulation dosage of H₂O₂ is 12mg/mL, and pH is 7.(4) Through the primary microorganism separation rig experiments, several advantages strains are obtained and identified to genera: SY₁ belongs to Microbacterium, SY₂ belongs to Nocardia, SY₃ belongs to Pseudomonas, SY₄ belongs to Bacillus.