Study on Migration Law of Runoff Pollutants in Bio-retention Tank

The migration law of runoff pollutants in bio-retention tank was studied through the experimental research, containing calculation formula of pollutants reduction coefficient. After that, the technology of reducing and controlling runoff pollution by bio-retention tank was demonstrated. The result showed that bio-retention tank can reduce runoff by 15%-85%, and the pollutant emissions can be cut by 35%-95%. At the same time, it had good ecological landscape effect. The study can provide a reference for the design method of road bio-retention tank in sponge city construction, and basic technical methods and parameters for the subsequent construction of comprehensive control platform for urban rainwater runoff and the layout optimization of comprehensive measures of water quality and quantity.

Study on the Migration Mechanism of Typical Characteristic Pollutants in Coking Enterprises

Groundwater pollution in north China is serious, which is mostly caused by complex factors. Aiming at the problems such as the unknown reasons for the differences in the migration characteristics of typical characteristic pollutants in the same medium and the unknown migration rules of complex pollutants in soil and groundwater, this paper selected a single sample and a mixed sample of typical characteristic pollutants in coking enterprises to carry out the static adsorption test. The results showed that the distribution coefficients of benzene series and aromatic hydrocarbon pollutants in soil-water were K_(d)benzene >K_(d)toluene >K_(d)ethylbenzene >K_(d)pyrene >K_(d)anthracene >K_(d)naphthene, and the distribution coefficients of ammonia nitrogen, phenols and cyanogen were K_(d)ammonia nitrogen >K_(d)phenols >K_(d)cyanogen. The overall distribution coefficient of benzene series was higher than that of PAHs, and it was easier to be adsorbed by silty loam. Different carbon and hydrogen mass and even electron distribution of typical characteristic pollutants led to differences in the migration characteristics of benzene and aromatic pollutants. The more carbon and hydrogen there were, the more even the electron distribution was, and the more difficult it was to migrate in the soil. Among the same kind of pollutants, the migration of complex pollutants was weaker than that of single pollutants. The research could provide the parameter basis for establishing the solute transport model of groundwater and the design basis for developing the related risk control and pollution prevention strategies.

Migration characteristics and profile control capabilities of preformed particle gel in porous media

Inspired by the viscoelastic displacement theory,a product called preformed particle gel(PPG)is developed as conformance control agent to enhance oil recovery and control excess water production.The migration law of PPG suspension in porous media is related to its deep profile control and displacement capability.Laboratory experiments indicate that PPG suspension has good viscosity increasing,and the apparent viscosity decreases with the increase of shear rate.PPG suspension is mainly elastic,and its network structure makes it have certain shear stability.PPG particles realize migration in porous media in the way of“accumulation and blockage/pressure increase/deformation and migration”.When the ratio of the PPG particle size to the pore throat diameter d ranges from 35.52 to 53.38,the particles can match through the porous medium.When the permeability difference of the parallel model is 5,PPG suspension has the highest profile improvement rate,69.10%.PPG suspension can adjust the planar heterogeneity,and increase the oil recovery rate by 20.75%.The PPG suspension can effectively start“cluster"、“film”and“blind end residual oil”,and has a high oil washing efficiency.The core NMR T2 spectrum shows that PPG suspension mainly reduces oil saturation in mesopores and macropores.After PPG flooding,the EOR capacity of small pores is the highest,39.11%.