NUTRIENT VALUE OF ORGANIC WASTE MATERIALS

Abstract

This thesis investigated four types of material, commercial peat-containing multipurpose composts, commercial peat-free multipurpose composts, non PAS100 certified local authority composted green wastes and anaerobic digestates (AD). The AD samples included liquid and solid materials from different stages of the anaerobic digestion of mixed waste food plus green waste and press water from a dry high solids digester. These materials were analysed to characterise them and assess their quality with respect to several parameters of PAS 100 or PAS 110 as appropriate. Pot experiments were carried out with ryegrass using the commercial peat-containing multipurpose composts, commercial peat-free multipurpose composts, and local authority composted green wastes as growth media and two soils treated with the AD samples as soil amendments. A field trial was conducted over three years to investigate the impact of Forth Resource Management Ltd PAS100 certified composted green waste alone or in combination with rockdust as soil amendments for improving soil quality on a restoration site close to land field site.