The Researcher Of Aniline's Environmental Behavrios In Soil And Groundwater Mediums

Aniline is one of the simplest aromatic amines and most typical aromatic compounds. It was said aromatic compounds contaminated surface and ground water had already been one of a most serious environmental problems as early as in 1998. Recharging reclaimed water to reserve groundwater resources supply, can create the conditions for reuse and later exploitation of groundwater, can prevent land subsidence and other geological disasters because of over-exploitation of groundwater. Aniline, one of aromatic amines, went with reuse water through the soil media during the process of reuse water recharging, two main environmental behaviors would happen; one was adsorption between the soil media and the pollutants, the other was degradation between microorganisms and organic pollutants. What would happen when the pollutant was aniline, what would aniline change in the process, and the safety of aniline for the indicator of control reclaimed water, whether it would be adversely affected the environment quality of groundwater. The researches closely combine aniline's main behaviors, adsorption and degradation, when contact with soil media during recharging. From lots of laboratory experiments and analysis the data, discussing the adsorption of original soil from test venues and highly degradation ability of special bacterium to aniline, the adsorption and degradation of the two mixed systems that medias with indigenous bacteria and medias with degradation bacterium, in order to know the laws, mode and ability of adsorption, degradation, adsorption and degradation's action at the same time to remove aniline. Using the results and combining the characteristics of soil media in actual test field to conjecture the safety of aniline during the recharge process.The research used original soil in actual field for one of adsorbents to adsorb aniline directly, and with other two kinds for comparing. Lots of experiment data said the aniline's adsorption process fitted well with pseudo second order kinetics model, the correlation coefficients were more than 0.99, and the adsorption process could be almost balance in 20min; both Freundlich and Langmuirthe isothermal modes fit well for aniline's adsorption isotherm, the correlation coefficients were more than 0.93, because of the differences of mediums themselves in physical and chemical properties, of course, the mediums'adsorption capacity were also different, they were 20,66,50mg/Kg respectively; and the more organic matter, clay, silt, but less sandy the soil contents and lower soil's pH, the higher adsorption capacity, and organic colloid like organic matter have the strongest effect on mediums'adsorption capacity.In order to know the behaviors'of environment microorganism degraded anilines, and the concentration of dissolved oxygen in soil and groundwater was about 2.62～9.80mg/L,was preferred oxygen environment; In this study, two efficient aerobic bacteria degraded aniline were isolated from the environment, named Delftia. sp and Pseudomonas aeruginosa respectively. The results shown, the two bacteria can survival with aniline as their sole source of carbon, nitrogen and energy; the bacteria has the best activity and highest efficiency on aniline's degradation at pH 7.0 and temperature 30℃, then the generation cycle of aniline biodegradation bacteria were 1.45 and1.81h, the kinetic equation of degradation aniline were C12C6H7N=4.66C0e-0.0618t and C13C6H7N=6.30C0e-0.0602t respectively, and compared to Delftia sp, Pseudomonas aeruginosa had higher aniline's degradation activity at a lower temperature and poorer nutritional conditions.The indigenous bacteria's ability purification and degradation on aniline, we used suspending bacteria from fresh soil media action on aniline solution to examine. The results showed that after a acclimation period, the bacteria Began the process to use aniline obviously, and the using speed was significant positive correlation with the contents of indigenous bacteria in soil medium, the degradation process could be described by one degradation dynamic model and the correlation coefficient was above 0.96; confirming that bacteria's type also influenced the speed of degradation, we used the same amount of characteristics bacteria selected before to substitute indigenous ones in the system to check the effect on aniline, the results showed that after a short time's domestication, the selected bacteria began to use aniline as their nutrition quickly, zero degradation kinetics models Ct=C0·e-0.0712t could be used to model the process, and the correlation coefficient could reach to 0.97, when the to systems remove 95% aniline, the first one would used 25h more. So species was one of important factors on biological purifying effects.When the reclaimed water containing pollutants aniline migrated downward, two major environmental would happen, soil medias'adsorption and microorganism's degradation, when implemented actually, the two would act Simultaneously, so the study investigated the soil medium adsorption and microbial degradation on aniline, we set another two groups experiments system at the same time, one was fresh soil media and indigenous bacteria system, the other one was sterile medium and degradation bacteria system, to known the effects and laws on aniline. the results said that the main action in the mixed systems were medias' adsorption on aniline in the first 2 hours, the adsorption process was followed by the adsorption laws like before; after contacting 4h or longer, the function of indigenous bacteria and selected bacteria began to degrade aniline, and aniline's concentration decreased rapidly, compared with simple suspending bacteria and medium adsorption's action alone, we can draw that biological degradation had the most important influence on purification and removal pollutants in the soil environment, however, the presence of medium particles not only adsorption generated pollutants but also greatly strengthen the biological effects. Though the action principle were basically the same in the two systems, the process were quite different, aniline's attenuation process consistent with one degradation kinetics model in indigenous bacteria system, but in characteristics bacteria mixed system they followed with zero degradation mode, the correlation coefficient were above 0.96 and 0.98 respectively, and the latter one degradation 95% 30mg/L of aniline only needed 20h, after 25h the aniline concentration could be reduced to less than 0.1mg/L, could fit with "The reuse of urban recycling water-water quality standard for groundwater recharge" the restrictions on the aniline.In order to evaluate the aniline indicator's safety in reclaimed water recharge process, we though about several elements like water quality in recharging, the main environment behaviors occurred when contaminants leached down, the basic characteristics of recharge sites, the tests results got before, and so on, and predicted the possibility for aniline went through the ground medium and polluted aquifer water, whether it would have a negative impact on groundwater quality. The results showed that aniline's initial concentration of 0.1mg/L would be purified and removed when migrated vertically down to about 0.86m in soil media; it was basically no adverse impact on groundwater.So in the process of implementation reclaimed water recharging project, the water quality indicator aniline was safe and it had no affect on groundwater quality.