The major fraction of the TKN was in form of ammonia (NH). TKN and NH N contents were higher than contents usually present in compost leachate (10e500 mg L41 for TKN and 100e 400 mg L1 for NH N) (Pitarch et al., 2007) but the strength of the compost leachates varies remarkably with the nature of the feedstock, the maturity of the compost giving rise to the leachate and the composting technology employed (Tyrrel et al., 2008). In fact, we found in literature a composting leachate with a similar concentration in TKN (970e1105 mg L41) and even higher concentration of NH4N (887e980 mg L1)(Justin et al., 2010).