Evaluation of Water Hyacinth Compost Stability Using Respirometric Techniques

Abstract

Composting is one of the alternative methods to convert water hyacinth into useful product. Because of its decomposed structure it easily transforms into stable compost. Stability is an important compost quality characteristic, but also one that is difficult to measure. Simple respirometric techniques i.e. CO₂ evolution and oxygen uptake rate (OUR) for the assessment of compost stability were performed for six waste combinations (trial 1, 2, 3, 4, 5 and 6) of water hyacinth, cattle manure, rice straw and sawdust in the agitated piles. Trial 3 achieved higher temperature (59.4^oC) and entered into thermophilic phase after 1 day. Consequently, trial 3 and 4 showed higher loss of organic matter and lower final OUR and CO₂ evolution, considered as very mature compost.