Composting garden and park waste

 - branches, leaves, grass... 

Solum Gruppen recieves garden and park waste from municipalities via I/S Vestforbrænding on a daily basis. The material is received at Store Hede Compost Center A/S and Nymølle Compost Center close to Roskilde, where it is then composted using the mattress principle. Solum Gruppen is the sole producer of mattress compost in Denmark.

Naturally, the nature of the raw materials varies according to the time of year and it is here that the mattress method really shows its benefits.

Mattress compost is produced over a 3-year time period. The mattress structure is built up over the first year. The incoming material is spread out in thin layers. In this way, the seasonal differences in the composition of the material are distributed evenly over the entire extent of the mattress. Typically, a mattress covers an area of 10,000 m2 (107,600 ft2) and a height of 4 to 5 meters (13 to 16 ft). This results in each mattress containing approximately 50,000 tonnes.

The material is broken down into a suitable size and structure. A loose structure ensures that oxygen and micro-organisms can work constantly on the waste. In the second year, the different layers in the mattress are homogenised by a process of regularly turning and mixing the material. This process is controlled with aeration and watering. Temperature and humidity gauges monitor and control the process. The temperature inside the compost is kept above 70ºC for long periods. This ensures that seeds from weeds and plant pathogens are killed off.

The temperature falls during the third year as the mattress matures.

A large amount of beneficial micro-organisms are built up during this period, ensuring the high quality of the compost.

The same quality requirements throughout the process guarantee a product of uniform quality. Therefore, all products can be described down to the finest detail.