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.

Variations in the chemical properties of landfill leachate

“…Contrary to the decreasing loading of organic pollutants in leachates with increasing age of the landfill, it is commonly observed that the concentration of axnmoniacal nitrogen increases rapidly. A study carried out in Germany indicated that after a period of three to eight years, tile ammoniacal nitrogen concentration reaches mean values between 500 and 1500 rag/liter and will remain at this level for at least 50 years (Hartmann and Hoffmann 1990). As anticipated, the leachate from GDB (old fill) still had high ammoniacal nitrogen concentrations (the highest value was 885 mg/liter).…”

“…With reference to the discharge limit of 50 mg/liter ammoniacal nitrogen and 200 mg/liter COD in Germany (Hartmann and Hoffmann 1990), this had important implications for leachate manage- …”

Combined treatment of landfill leachate with fecal supernatant in sequencing batch reactor

“…However, little research has been done on combined treatment of landfill leachate and fecal supernatant. Combined treatment of landfill leachate and fecal supernatant has many advantages (including organic carbon for denitrification supplied) such as economy, and better control of the influent characteristics, because leachate pollution loads and flow rates have, in general, great variations in time (Hartmann and Hoffmann, 1990).…”

Impact of Landfill Closure Designs on Long-Term Natural Attenuation of Chlorinated Hydrocarbons

“…The change in basic inorganic chemistry can be a useful initial indicator of the occurrence and scale of organic releases from MSW landfills (Barr and Fernandez, 1980). Additionally, it has been commonly observed that the concentrations of ammonia and nitrogen increase rapidly within a landfill over time (e.g., Hartmann and Hoffmann, 1990;Chu et al, 1994).…”