Application of Graded Limestone as Roughing Filter Media for the Treatment of Leachate

Abstract

This chapter examined limestone performance as a roughing media for pollutant removal from leachate using a filtration column. Limestone with a density of 2554 kg/m3 was crushed and graded between 4-6, 8-12 and 12-18 mm as filter media. The length of run for each experiment of the various individual media sizes and combination sizes was 10 days. Test analysis was performed at intervals of 24 hours to ascertain the percentage removal efficiency for the parameters desired. The observed best removal occurred when a combination of 4 – 8mm, 8 – 12mm and 12 – 18mm, media top to bottom was used. This obtained a BOD removal in the range of 22 to 81%, COD was 22 to 75%, and turbidity was 32 to 86% while the colour was 36 to 62%, respectively. A general decline in removal efficiency was observed after the sixth day showing maximum adsorption and breakthrough had been achieved. The study indicates that limestone is an effective adsorbent that can be used for short-term treatment of leachate.