Goody water or leachate is often the negative centre of attention as a source of odour emission and mainly stored somewhere out of the way in a pit under bad conditions. However, the function and importance of percolate water is underestimated and deserves more attention as one of the most important raw materials.
Goody water is collected process water released in phase 1 2 and 3 and topped up with rainwater that flows over the composting floor. This water is rich in nutrients and micro-organisms which are essential at the start and further process of fermentation.
To prevent anaerobism, goody water must be adequately aerated; otherwise toxins may be formed which cause the microflora composition to change. This often causes the irritating stench. A less than optimally running fermentation process can often be traced to anaerobic goody water. The consequences are visible in phase II and III as slow breakdown of ammonia too high pH-values and bad mycelium growth.
Aeration can be done in various ways; injecting air at the bottom of the tanks blowing in air from above using floating fans or pumping the goody water up from below and aerating as a thin film of water.
Con Hermans, AdVisie ‘The mushroom cultivation advisors’