The PP, which operated from January 2003 to October 2011, received up to 90% of indistinct municipal waste. Thus, the deposition of highly biodegradable waste, as well as PP’s period of operation, explains not only the aforementioned high COD and low BOD5 concentrations but also relatively high and stable ammonia concentration (2114 ± 323 mg N–NH4/dm3) (Figs. 2 and 3)