Proceedings

Abstract: This project aims to develop a new sludge management concept that reduces the volume of sludge, using a more energy efficient process and produce a number of products which are useful for society. END-O-SLUDG (www.end-o-sludg.eu) is an EU FP7 project involving 14 partners from 5 European countries. Using an integrated approach with emphasis on the whole wastewater treatment system, the project researches innovative system solutions that have the potential to achieve up to 20% annual carbon savings for the water industry by 2020, and ultimately could deliver up to 15 million tonnes CO2 eq per annum savings for Europe. New products will be produced for application to agricultural crops that develop the concept of organo-mineral fertiliser (OMF) reported by Gedara et al 2009. This presentation will describe continuing field experiments being undertaken as part of the END-O-SLUDG project to assess the agronomic performance of these novel fertiliser materials on commercial crops of grass cut for silage wheat triticale and oats grown at Broxton in Cheshire. Previous work on forage maize, oilseed rape and wheat treated with organo-mineral fertilisers produced statistically similar crop yields compared to crops treated with conventional fertilisers. The results of experiments carried out in the 2011/12 growing season will be presented, together with a summary of three years wheat data.

Keywords: END-O-SLUDG, biosolids, sewage sludge, heavy metals.

Introduction: The rapid increase in world population over the last 50 years has put substantial pressure on agriculture to provide sufficient food (Chrispeels and Sadava, 2003). It is estimated that 48% of food produced today results directly from the use of fertilisers (Erisman et al., 2008). In addition to this world population has been predicted to soar further in the next 40 years, with a 50% increase predicted by 2050. Arguably this will increase pressure on all aspects of farming to meet the food needs of the increasing population.

Many arable systems today rely solely on inorganic (man-made) fertilisers for additional nutrients due to price, availability and the greater understanding and better estimation of the nutrients available. The production of inorganic fertilisers relies heavily upon fossil fuels and other natural resources and as these become increasingly difficult to source the fertilisers will be less available, the price will increase. Thus, this has led to a renewed interest in organic fertilisers.

Biosolids are a bi-product from human sewage processing which in addition to the nutrients they supply there are also other benefits, adding soil organic matter and increasing water holding capacity. The production of biosolids has increased since 2000 according to DEFRA (Department for Environment, Food and Rural Affairs) (DEFRA, 2006a).

The water treatment industry, is under increasing pressure to reduce its’ impact on the environment, unfortunately the material that is processed to made sewage sludge( The Code of Practice of Agricultural Sewage Sludge defines sewage sludge as “…the residue collected after treatment of the contents of urban drainage systems (DEFRA, 2006b).”) containing human wastes; surface run-off and industrial wastes. More than 30 million tonnes of wet sewage sludge is produced in the UK each year (Davis, 1987). If this wet sludge can by removal of water be converted into into biosolids this should allow the water industry to recycle their waste whilst providing agriculture with an effective fertiliser.

Previous trial work (Chaney et al. 2011) suggested that similar yields may be achievable across a range of crops when biosolids are compared to conventional fertiliser. This paper will discuss the results from trial work completed in in the 2011/2012 growing season using both conventional fertilisers and biosolids in the NPK ratio of 3:8:0 in addition to three years of winter wheat data.