Sludge Watch ==> Hargreave: Review of the use of composted municipal solid waste in agriculture..

[Maureen Reilly]

>From David Wimberly, Nova Scotia:

Too bad that source-separated MSW compost, which is generally quite clean 
and beneficial, is often mixed with low quality sludge compost.
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Hargreaves et al., 2007. A review of the use of composted municipal solid 
waste in agriculture.  Agriculture, Ecosystems & Environment.  Article in 
Press.

Abstract

Municipal solid waste (MSW) compost is increasingly used in agriculture as a 
soil conditioner but also as a fertilizer. Proponents of this practice 
consider it an important recycling tool since MSW would otherwise be 
landfilled and critics are concerned with its often elevated metal 
concentrations. Large amounts of MSW compost are frequently used in 
agriculture to meet crop N requirements and for the addition of organic 
matter. The main concern is loading the soil with metals that can result in 
increased metal content of crops. Furthermore, in some cases, metals and 
excess nutrients can move through the soil profile into groundwater. 
Municipal solid waste compost has also been reported to have high salt 
concentrations, which can inhibit plant growth and negatively affect soil 
structure. A review of relevant agricultural studies is presented as well as 
recommendations for improving MSW compost quality. Its safe use in 
agriculture can be ensured with source separation (or triage of MSW to be 
composted) as well as the development and implementation of comprehensive 
industry standards.

Sludgewatch Admin:

David Wimberly has it right.  Mixing sewage sludge with municipal compost 
(like in that expensive Edmonton co-composter) bumped up the heavy metals so 
high that they couldn't sell the compost as a soil ammendment.