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Sludge & Waste Management 

Exploring attitudes and perceived barriers to the use / recycling of biodegradable products containing sewage sludge

Reference: 15/SL/13/5
ISBN: 1 84057 796 7
Published Date: 17/12/2015

Sewage sludge is one of a number of biodegradable organic wastes produced in significant quantities in the UK. These wastes contain valuable nutrients and as a result, products derived from these materials are widely used as fertilisers and soil improvers for assisting plant growth. However, there are barriers to combining and treating sewage sludge with other organic materials to produce biodegradable products containing sewage sludge (BiPS).

The aims of this project were to identify and understand the barriers to the use of BiPS by investigating BiPS products and markets available around the world, their associated hazards and risks and how these have influenced the development of relevant regulations and standards. Perceptions are a very important factor in determining how BiPS is used so the project also sought to understand the perceptions and attitudes to the management and use of BiPS of key stakeholders as well as the general public.

To address the barriers to the use of BiPS in the UK the water industry needs to work closely with stakeholders to explore how to change the regulatory landscape, possibly by establishing product quality standards for different end uses, underpinned by ongoing research into potential hazards in order to provide widespread confidence. The public is generally unaware of the use of sewage sludge and BiPS and further research is required to provide a better understanding of the extent and strength of their views.

Price: £450  

Using sludge from advanced anaerobic digesters to reduce the rate of phosphorous run-off from farm slurry

Reference: 15/SL/02/11
ISBN: 1 84057 795 9
Published Date: 06/11/2015

 The water soluble phosphorus (WSP) content of organic materials is directly related to their potential for P transfer in run-off after land application. Biosolids have a lower WSP than livestock slurry and hence a lower risk of P loss in run-off. The addition of biosolids to livestock slurry at an appropriate rate could reduce the WSP content of the resulting mix due to the binding properties of certain biosolids (as a result of iron-Fe, aluminium-Al and calcium-Ca cations).

A series of experiments were undertaken using a range of biosolids products added to cattle slurry at a variety of mixing rates. The experiments showed that mixing biosolids, or in particular clean water sludge, with slurry did decrease the WSP of the slurry/biosolids mix (compared to slurry). Similarly, the PSYCHIC model predicted a reduction in total catchment P losses, following the addition of the mixed organic material, in comparison to separate applications. 

Price: £250  

Biosolids: Soil Quality and Fertility Benefits

Reference: 15/SL/01/8
ISBN: 1 84057 780 0
Published Date: 23/07/2015

Biosolids are a valuable source of available plant nutrients and stable organic matter, which can reduce manufactured fertiliser costs and benefit soil structure and fertility. This study investigated the effects of twenty years of repeated biosolids applications at four experimental sites.

Soil samples from the sites were analysed for a range of soil chemical, biological and physical properties; measurement of serial crop yields and quality were also made. The report provides scientifically robust experimental evidence on the benefits of long-term biosolids applications to soil quality and fertility and to the nutrient supply to crops.

The results of the study provide information on the benefits of biosolids use, further helping to secure the agricultural landbank for biosolids recycling.

Price: £200  

Biosolids: Good Practice Guidance

Reference: 14/SL/11/7
ISBN: 1 84057 730 4
Published Date: 09/06/2014

This biosolids good practice guidance document is intended to provide advice and information to knowledgeable practitioners on sustainable biosolids recycling to agricultural land. The guide covers the treatment of sewage sludge to produce biosolids, the benefits associated with using biosolids in agriculture and regulatory requirements.
Following the guidance in this document will help practitioners get the most from biosolids applications to agricultural land. From a water industry perspective, the good practice guidance developed in this project will enable operators to secure a sustainable landbank and 'recover' more value from biosolids sales; helping to offset treatment, transportation and application costs.

Price: £150