Nitrate removal using compost and pine bark as a carbon source.

Abstract

Emissions resulting from waste degradation processes have a high polluting potential and are responsible for negative impacts on the environment. Landfill leachate is hazardous for the human health and the environment and requires treatment before being discharged, in order to comply with the South African legislation indicated in the Government Gazette, 1999. However, treated leachate may still contain high levels of nitrate that require an additional denitrification step. Biological denitrification occurs with the addition of a carbon source that increases the operational costs of the process, particularly if chemical compounds are employed (such as methanol). This research aims to explore the efficiency of denitrification using low cost carbon sources such as garden refuse compost and pine bark, easily available in South Africa and currently disposed of in general waste landfills. Denitrification processes in fixed bed reactors were simulated in laboratory scale leaching columns packed with immature compost and pine and irrigated with biologically treated leachate from the Mariannhill landfill site Sequencing Batch Reactor (SBR). The overall objective is to assess efficiency, kinetics and performance of the substrates using batch tests and columns tests. A secondary objective is to assess the feasibility of using organic waste compost and pine bark as by product of an integrated waste management system to denitrify landfill leachate.