So what overall points are we raising in this article? Well there seems to be a problem with defining limits for PTEs in digestates because of the liquid state of many digestate products. In order for digestates to retain EoW status within the PAS110 specification, quite lenient PTE criteria have been devised, which could lead to significant quality differences in dilute liquid digestates. PTE controls required for digestates are no better than that applied to sewage sludge, indeed may be poorer especially for arsenic, and yet digestates can achieve EoW status. We ask the question of whether there are underlying stakeholder interests driving the PAS110 rather than sound science and whether it would be more prudent to have a level playing field based on good science. We believe that this a debate which should be had in the open, and we hope that this short article will provoke some responses and discussion.
|Number of pages
|Published - 2 Nov 2015