Slambehandling med Effektive Mikroorganismer (EM teknologi)

English Summary

The object of this report is to study the effect of EM 1 (Effective Micro-organisms) used as an inocular in compost processes with the purpose to break down PAH, DEHP, LAS and NPE (PAH etc.) in waste water sludge. Experiments with app. 12 kg. of waste water sludge has been carried out from Dec. 1997 until Jun. 1998. The sludge was mixed with Bokashi (Bokashi = organic matter fermented with EM) and initially treated anaerobically and aerobically afterwards.

Test results from samples from the experiment with EM and three control groups added -water, -water and sugarcane molasses, - water sugarcane molasses and a inoculation consisting of microorganisms from the sludge respectively, showed only small differences.

At least two conditions related to the experiment have made it impossible to conclude anything final about EM’s ability to break down PAH etc. in sludge.

Firstly, the sludge contained only a small amount of PAH etc., some of the analyses showing not even detectable levels. This fact makes it impossible to conclude anything about the effect of EM.

Secondly, the piles were too small to sufficiently keep the heat under the aerobic compost process . In this way the piles turned cold and the compost processes stopped. This is fatal to the experiment because the brake down of PAH etc. often is related to the processes in the aerobic phase of the treatment.

By comparing the results from the analyses of heavy metal in compost with EM and compost with only water it shows that the compost with EM contained a smaller amount of all heavy metals measured for. At the time being it is not possible to explain these differences.