Using sludge as fertiliser

Sludge is used as fertiliser on arable land. In compliance with the National Environmental Objectives, VA SYD is engaged in sludge application on arable land. We have 30 years of experience in field tests with sludge. 

WHAT IS SLUDGE? 

During the purification process at the wastewater treatment plants, sludge is formed as an important residual product. The sludge contains large amounts of biologically degradable material and plant nutrients. 

Sludge is highly nutritious and is often used as fertiliser (plant nutrients) on arable land, primarily as a phosphorus source. Phosphorus is a vital substance for the growing of crops. The treated sludge ready to be applied on arable land, looks and feels like humus-rich soil. Humus-rich soil is capable of holding humidity and has a positive effect on farming. 

OUR WORK IS GOVERNED BY THE NATIONAL ENVIRONMENTAL OBJECTIVES

VA SYD's operations are in compliance with the National Environmental Objectives set up by the Swedish Parliament. One of the goals for environmental quality is to return phosphorus to arable land as fertiliser. By spreading the sludge, the nutrients in the sludge are returned to the arable land. This completes the nutrient cycle between city and rural area.  

The Environmental Objectives Council follows up the Environmental Objective to use the nutrients in the sludge (new window

CHECK-UPS AND CERTIFICATES 

Of course the sludge spreading shall be carried out under controlled conditions and with constant improvement of the sludge quality. This means that we undertake to comply with even stricter requirements than what is stipulated in the existing regulations. Because of our high standards, VA SYD is aiming at the certification called REVAQ of the sludge produced at all our wastewater treatment plants. 

We are also strongly committed to improving the wastewater quality, and thereby sludge quality. We run public information campaigns regarding what should be flushed down the drain, as well as demand restrictions on the industrial use of chemicals. 

VA SYD's REVAQ certification 

 

WORLD-UNIQUE EXPERIMENTS – 30 YEARS OF EXPERIENCE 

VA SYD has been conducting field trials for 30 years on arable land in Lund and Malmö. We have conducted systematic studies on the impact of sludge on the soil and the crop. The results unequivocally indicate that the cadmium content in the crop does not increase because of sludge application. 

The trials show positive effects of sludge application. One effect is that the soil has a higher humus content which makes it easier to till with better capacity to retain humidity. 

The field trials have been compiled in a report: 

"Sludge application on arable land – field trials with municipal sewage sludge from Malmö and Lund between the years 1981-2008" (new window, pdf)