Nitrogen transfer from grey municipal solid waste to high quality compost

Ammonia was transferred from an anaerobically digested mixed waste at high pH (due to addition of 10% CaO) to an actively nitrifying, high quality mature vegetable-fruit-garden compost. After 5 days indirect contact with the anaerobic compost, by laying a sieve in-between the two materials, the recipient aerobic compost exhibited a rapid increase in NH4+-N concentration, followed by a subsequent decrease due to nitrification. The nitrifying activity (ammonium oxidation rate) was 94 mg NO2--N/kg DW.d in the treated aerobic compost. In the non-treated aerobic compost, the activity was 22 mg NO2--N/kg DW.d. The treated aerobic compost contained 967 mg NO3--N/kg DW. In the control aerobic compost, the amount was 291 mg NO3--N/kg-DW. The treated aerobic compost can serve as a readily available N source to ensure rapid crop development. This methodology increases the agricultural value of the compost for areas where industrial fertilisers may not be advisable or available. (C) 2000 Elsevier Science Ltd. All rights reserved.