Co-incorporation of biodegradable wastes with crop residues to reduce nitrate pollution of groundwater and decrease waste disposal to landfill

Return of high nitrogen (N) content crop residues to soil, particularly in autumn, can result in environmental pollution resulting from gaseous and leaching losses of N. The EU Landfill Directive will require significant reductions in the amounts of biodegradable materials going to landfill. A field experiment was set up to examine the potential of using biodegradable waste materials to manipulate losses of N from high N crop residues in the soil. Leafy residues of sugar beet were co-incorporated into soil with materials of varying C:N ratios, including molasses, compactor waste, paper waste, green waste compost and cereal straw. The amendment materials were each incorporated to provide approximately 3.7 t C per hectare. The most effective material for reducing nitrous oxide (N2O) production and leaching loss of NO3− was compactor waste, which is the final product from the recycling of cardboard. Adding molasses increased N2O and NO3− leaching losses. Six months following incorporation of residues, the double rate application of compactor waste decreased soil mineral N by 36 kg N per hectare, and the molasses increased soil mineral N by 47 kg N per hectare. Compactor waste reduced spring barley grain yield by 73% in the first of years following incorporation, with smaller losses at the second harvest. At the first harvest, molasses and paper waste increased yields of spring barley by 20 and 10% compared with sugar beet residues alone, and the enhanced yield persisted to the second harvest. The amounts of soil mineral N in the spring and subsequent yields of a first cereal crop were significantly correlated to the lignin and cellulose contents of the amendment materials. Yield was reduced by 0.3–0.4 t/ha for every 100 mg/g increase in cellulose or lignin content. In a second year, cereal yield was still reduced and related to the cellulose content of the amendment materials but with one quarter of the effect. Additional fertilizer applied to this second crop did not relieve this effect. Although amendment materials were promising as tools to reduce N losses, further work is needed to reduce the negative effects on subsequent crops which was not removed by applying 60 kg/ha of fertilizer N

Hazard analysis and critical control point (HACCP) for composters

Includes bibliographical referencesSIGLEAvailable from British Library Document Supply Centre- DSC:m03/29316 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Occupational and environmental exposure to bioaerosols from composts and potential health risks A critical review of published data

Includes bibliographical referencesAvailable from British Library Document Supply Centre- DSC:7761. 864(130) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

A sustainable product needing a sustainable procurement commitment: the case of green waste in Wales

European waste legislation aims to reduce the amount and type of waste that is sent to landfill. Hence member states are investigating alternatives, and trying to treat waste as a resource. In the UK there is a focus on producing compost from biodegradable waste. This emphasis is particularly strong in Wales, where strategy encourages the collection and composting of green garden waste. A survey has been conducted within the composting industry in Wales to determine the barriers that need to be overcome in order for green waste compost to become an accepted and viable product. The research investigates purchasing preferences, and identifies the important role of specifications in purchasing decisions. Welsh policy initiatives support the concept of sustainable development and encourage sustainable procurement. However, practical actions are required to turn these policies into practice. This study suggests how sustainable procurement initiatives could be used to facilitate the inclusion of green waste compost in contract specifications and hence enable public bodies to close the recycling loop. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.