ENVIRONMENTAL IMPACT OF WASTE BASED BIOGAS DIGESTATES AS INFLUENCED BY POST-TREATMENT METHODS

Biowastes contain valuable plant nutrients. After being processed, they could be used as fertilizers. Yet therefore among other things their environmental impacts should be known. The impacts of biowaste digestates composted after fermentation and processed in three different ways - were tested using two bio-tests with earthworms and two with plants. None of the tests with earthworms led to negative effects within the tested ranges. The tests with plants showed a slightly negative response especially of monocotyledonous plants (Avena sativa in the test) towards the pure compost but not towards the further worked up products. For dicotyledonous plants (here represented by Brassica rapa) no negative effects were found within the tested ranges. The results of the conducted tests indicate that bio-wastes from households, if treated in an appropriate way, could be used as fertilizers without negative impacts to plants and earthworms.