The nitrification of the liquid phase of digestate (LPD) was conducted using a 5L completely stirred tank reactor (CSTR) in two independent periods (P1 - without pH control; P2 - with pH control). The possibility of minimizing nitrogen losses during the application of LPD to the soil as well as during long-term storage or thermal thickening of LPD using nitrification was discussed. Moreover, the feasibility of applying the nitrification of LPD to the production of electron acceptors for biological desulfurization of biogas was assessed. Despite an extremely high average concentration of ammonia and COD in LPD reaching 2470 and 9080mg/L, respectively, nitrification was confirmed immediately after the start-up of the CSTR. N-NO3-concentration reached 250mg/L only two days after the start of P1. On the other hand, P1 demonstrated that working without pH control is a risk because of the free nitrous acid (FNA) inhibition towards nitrite oxidizing bacteria (NOB) resulting in massive nitrite accumulation. Up to 30.9mg/L of FNA was present in the reactor during P1, where the NOB started to be inhibited even at 0.15mg/L of FNA. During P2, the control of pH at 7.0 resulted in nitrogen oxidation efficiency reaching 98.3±1.5% and the presence of N-NO3-among oxidized nitrogen 99.6±0.4%. The representation of volatile free ammonia within total nitrogen was reduced more than 1000 times comparing with raw LPD under these conditions. Thus, optimum characteristics of the tested system from the point of view of minimizing the nitrogen losses as well as production of electron acceptors for the desulfurization of biogas were gained in this phase of reactor operation. Based on the results of the experiments, potential improvements and modifications of the tested system were suggested.

• MeSH
• amoniak MeSH
• bioreaktory * MeSH
• dusík MeSH
• dusitany MeSH
• nitrifikace * MeSH
• Publikační typ
• časopisecké články MeSH

The objectives of the study were to compare the effects of the composting and the vermicomposting processes on the distribution of particles into three size fractions, and to assess the agrochemical properties of the size fractions of the composts and the vermicomposts. Three different mixtures of biowaste were subjected to two thermophilic pre-composting, and then the mixtures were subsequently subjected to 5months composting and vermicomposting under laboratory conditions. Vermicomposting was able to achieve the finer and more homogeneous final product compared to composting. For compost, the highest portion of the finest fraction was achieved from products which originated from kitchen waste containing used paper, followed by digestate with straw, and finally sewage sludge with garden biowaste. In most cases, compost particles which were less than 5mm exhibited the better agricultural potential than coarser compost. However, agrochemical properties of the finest vermicompost exceeded classical compost.

• MeSH
• biodegradace MeSH
• odpadky - odstraňování metody   MeSH
• odpadní vody chemie   MeSH
• Oligochaeta MeSH
• papír MeSH
• půda chemie   MeSH
• velikost částic MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The objective of this study was to evaluate the mobility of Cd, Cu, Pb and Zn during 3 different compost aeration rates of household bio-waste, originating in urban settlement (U-bio-waste) and family house buildings (F-bio-waste). The first two weeks, when the thermophilic composting phase became, the highest decline of exchangeable content was recorded. After 12 weeks of composting, lower exchangeable content was found in the case of U-bio-waste composts than F-bio-waste composts, despite higher loss of fresh mass. The order of fractions in both final composts was as follows: residual>oxidizable>reducible>exchangeable. The exchangeable portion of total content in final composts decreased in this order: Zn (17%), Cd (11%), Pb (4%) and Cu (3%). Regarding the low exchangeable content of heavy metals and high-quality organic matter, these types of composts could be used not only as fertilizer, but for remediation of metals contaminated land.

• MeSH
• biomasa MeSH
• chemická frakcionace MeSH
• dusík analýza   MeSH
• koncentrace vodíkových iontů MeSH
• neparametrická statistika MeSH
• odpadky - odstraňování * MeSH
• půda * MeSH
• roční období * MeSH
• těžké kovy analýza   MeSH
• uhlík analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH