Studies On Mechanics And Treatment Of Groundwater Pollution From Landfill

The dumpling of refuse disposal and the environmental problems created by dumps isa hard nut to crack in the world today. More and more attention is paid to theseproblems.Landfill is the most common way of waste disposal in most cities of China, whichwould inevitably lead to environmental pollution. The research is part of the programThe Geochemical Effect and Mechanics of Municipal Landfill sponsored by NationalNatural Science Foundation of China with Taitou landfill site in Shijiazhuang asexample. To probe the production, transport and biodegradation of pollutant fromlandfill,a Serial of modeling and controlling tests were carried out.First we investigated the landfill site in detail and collected large number of water, soil,garbage and leachate samples for indoor experiments to simulate the production ofleachate from old and newly dumped garbage. Mathematical statistics were applied topredict the production of leachate according to the experiment results.With the downward transport of leachate, lots of complicated physical, chemical andbiological reactions take place. Diluting, adsorption-desorption, precipitation-dissolution, complexion, exchange of ions, oxidation-reduction reaction as well asmicroorganisms' function were discussed in detail in this dissertation to reveal theproduction mechanism and composition of the refuse leachate. Mathematical modelswere adopted to describe the concentration changes and various reactions in theleachate.As the main part of pollutant from municipal garbage is organic, microorganisms playimportant role in their degradation and transformation. Through microbialtransformation experiments the distribution and activities of some keymicroorganisms were made clear. The coupling of solute transport model, flow modeland kinetic model of biodegradation was used to describe the reactions in leachatetransport, especially the .biodegradation. Since the coupling model took into consideration such actions as dispersion, convection, chemical reaction, water-rockinteraction, biodegradation etc., it is the extension and deepening of solute transportmodel.Some bacteria with high degrading capacity, separated from sludge, waste water,leachate etc., were used in the pollution control experiments after acclimatization andpreliminary treatment. The result proved their high efficient in the control of leachatetransport and the removal of organic and nitride pollutant. The overall removalefficient of subsurface biological barrier is over 95%.At the same time, some new knowledgewere gained on certain problems encounteredin in-situ biological treatment of groundwater pollution, such as the subsurfaceactivities of microorganisms, secondary pollution and aquifer clogging etc.