Hazardous Waste Landfill Sites Research Articles

Nitrogen loss in a nitrifying rotating contactor treating ammonium-rich wastewater without organic carbon

Extensive loss of nitrogen (up to 70% of ammonium oxidized) is observed in a nitrifying rotating biological contactor (RBC) treating ammonium-rich leachate from a hazardous-waste landfill site. Due to pretreatment (precipitation, flocculation, sedimentation, BOD removal, activated carbon adsorption), the DOC is less than 20 mg/l. Heterotrophic denitrification can therefore be excluded. The nitrification rate reaches 3-4 g NH4-N m-2 d-1 at a pH of 7-7.3 in the first two compartments of the three-stage RBC. An increasing partial pressure of oxygen and ammonium concentration favor nitrogen removal over ammonium oxidation. The reduction of nitrite might therefore be strongly coupled with ammonium oxidation. The degradation mechanism is not yet known. Two possibilities are suggested: (i) nitrite produced in the aerobic biofilm layer close to the surface diffuses into deeper anoxic layers of the biofilm and is reduced in parallel with ammonium oxidation similarly to the Anammox process, or (ii) nitrite produced by Nitrosomonas is reduced by NADH2+ generated during hydroxylamine oxidation.

Technical Standards for the Construction of Hazardous Waste Landfills in Germany Documented at the Hazardous Waste Landfill Site at Raindorf

The most important German administrative regulations for the disposal of hazardous waste are described. In addition, some constructions at the landfill at Raindorf are introduced which have been installed to meet the demands of these regulations. Resulting from these experiences, several recommendations for the design and the construction of a modern, hazardous waste landfill are given.