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The influence of pressure swing conditioning pre-treatment of chicken manure on nitrogen content and methane yield

Schumacher, Britt, Wedwitschka, Harald, Weinrich, Sören, Mühlenberg, Jana, Gallegos, Daniela, Oehmichen, Katja, Liebetrau, Jan
Renewable energy 2019 v.143 pp. 1554-1565
ammonium nitrogen, biogas, continuous fermentation, gases, kinetics, methane production, pellets, poultry manure, straw
The purpose of this study was to examine if the energetic potentials of chicken manure can be used more efficiently in the biogas process by means of pre-treatment with pressure swing conditioning (PSC). Two sub-questions were of interest: the effect of pre-treatment on the nitrogen content in the manure and the effect of pre-treatment on the methane yield. Six variants of PSC were examined concerning nitrogen content and methane yield in batch tests. PSC-variant 150 °C/5 min showed an increase methane yield of 14.4% (to 288 mL/gVS) in best case compared to the untreated reference. The result's kinetic model analysis indicate faster degradation rates. PSC-treatment caused a reduction of the total ammonia nitrogen content of 39% on average of the six variants (via gas phase). One PSC-variant and untreated chicken manure were chosen for continuous fermentation tests in continuous stirred tank reactors in lab-scale. In the continuous test a methane production of 294 mL/g VS for untreated manure was observed and of 297 mL/g VS for PSC-chicken-manure (150 °C/5 min). With the right parameter set, PSC is able to enhance the degradation speed and to decrease the total ammonia nitrogen content of chicken manure with straw pellets as bedding material.