As part of its efforts to ensure toxin-free and resource-efficient closed-loop "eco-cycles", the Swedish Government has appointed Dr Gunnar Holmgren former Governor of Västernorrland County and Director-General of the Defence Materiel Administration, to head an inquiry that aims to propose a ban on the spreading sewage sludge while introducing a requirement for phosphorus to be recycled from sewage sludge.
Phosphorus is a vital plant nutrient. Sewage sludge is sometimes used as an agricultural fertiliser in Sweden because it contains large quantities of phosphorus. However, sewage sludge may also contain substances that are hazardous to the environment and human health, and only around 30 percent is currently spread on agricultural land while the remainder as landfill cover.
The Government wants to create the conditions for a circular economy, in which waste is treated as a resource. The aim of the inquiry is to ensure that phosphorus is recycled from sewage sludge in a non-toxic and safe manner so that it can be used to a greater extent in agriculture.
It is important that we use our resources responsibly. Phosphorus is a valuable resource, and as such we should use the technologies available to utilise it, said Karolina Skog, Swedish Minister for the Environment.
A limited resource, phosphorus is an important component of mineral fertilisers and is currently imported to Sweden. Making better use of the phosphorus found in sewage sludge will help increase Sweden’s phosphorous self-sufficiency.
The inquiry is expected to result in proposals for a requirement to recycle phosphorus from sewage sludge. However, since sewage sludge also contains substances that are hazardous to the environment and human health including pharmaceutical residues and microplastics, the inquiry is also expected to propose a ban on spreading sewage sludge on agricultural land.
Reports show that in addition to metals that are hazardous to the environment and human health, sewage sludge also contains some microplastics. A ban on fertilisation using sewage sludge will reduce the risk of microplastics entering the environment in which our food is grown, said Minister Skog.
However, a ban on spreading sewage sludge should not be seen as an obstacle to the production of biogas. The aim is for both energy and phosphorus to be extracted from sewage sludge without any risk of emitting substances that are hazardous to the environment or human health into the environment.