The Use of a Soil Ameliorant based on Fly ash and Sewage Sludge Wayne F. Truter 1 , Norman F.G. Rethman 1 , Kelley A. Reynolds 2 and Richard A. Kruger 3 1 Department of Plant Production and Soil Science, University of Pretoria, Pretoria , 0002, South Africa 2 Eskom Technology, Private Bag 40175, Cleveland, 2022, South Africa 3 Ash Resources, PO Box 3017, Randburg, 2125, South Africa KEYWORDS: Sewage sludge, fly ash, lime, acidic soils, soil amelioration, crop productivity ABSTRACT Due to limited prime agricultural land, South Africa is heavily reliant on the use of acidic and nutrient deficient soils to meet the needs for increased food production. Environmental legislation has, however, placed restrictions on the application of sewage sludge to agricultural land. The prime concern being the accumulation of heavy metals and risk of disease. Previous research has, however, indicated that sewage sludge can be pasteurized and the toxic metals present in the sewage sludge immobilized, when it is treated with a mixture of Class F fly ash and lime. This product (SLASH) has been shown to have significant amelioration properties when applied to acidic soils, resulting in enhanced crop productivity. This work describes the beneficial effects of SLASH incorporation into soils, in comparison to the individual ingredient treatments (sludge, fly ash and lime). It is shown that SLASH incorporation at 2.5%, 5%, 7.5% and 10% of the soil volume, provides prolonged growth enhancement and yield increases over several cropping cycles. Positive effects on pH, Ca, Mg, and P were recorded, and two possible translocated heavy metals (Ni, Cd) and the important micro- nutrient (B), which is toxic at high levels, are not translocated in significant amounts. SLASH definitely has beneficial effects on both soils and crops! INTRODUCTION Previous work by Reynolds et al (1999) to determine the feasibility of converting waste disposal problems into a soil benefication strategy has proven true. The co-utilization of fly ash and sewage sludge with added lime has delivered a product termed SLASH (that contains 60 % fly ash, 30 % sewage sludge and 10 % lime on a dry matter basis) which has beneficial soil ameliorant effects. Two problems experienced in the past were that, sewage sludge contains heavy 2001 International Ash Utilization Symposium, Center for Applied Energy Research, University of Kentucky, Paper #80. Copyright is held by the Authors. http://www.flyash.info