Leachate Treatment: Design Recommendations for Small but Extremely Fluctuating, Highly Polluted Quantities of Water

Abstract

Today's practice in leachate treatment and disposal in the FRG comprises two possibilities:a) the combined leachate domestic wastewater treatment (transportation to the treatment plant either using the sewer system or tank trucks)b) complete, decentralized treatment at the source of the leachate production. As a result of the updating of the general water management law (WHG § 7a) the discharge of waste waters containing dangerous substances (e.g. AOX) into sewer systems is no longer permitted. As there is no possibility of a selective removal of the hazardous substances, the future consequence will be that the whole amount of leachate has to be treated at the landfill site. Existing leachate treatment plants are often designed for average loading rates. Because of the high fluctuations of the leachate quantity such plants are often overloaded. In the past there were two solutions:a) temporary transportation to a municipal treatment plant using trucks,b) recycling of the excessive leachate volume. As transportation is no longer accepted there is only the possibility of recycling left. The feasibility of buffering the runoff peaks has not yet been studied in detail (reservoir management). This cost-favourable option (earth basin with sealing) offers two advantages. First, the plant design can be based on mean conditions while secondly the loading of the plant will be almost constant (no variation concerning the hydraulic loading; concentration equalization effect of the storage tank). Herewith an attractive way of adapting existing plants to the time dependent changing requirements is available.