Simbayi, T.M.; Rashama, C.; Awosusi, A.A.; Nkuna, R.; Christian, R.; Matambo, T.S. Investigating the Anaerobic Digestion of Water Hyacinth (Eichhornia crassipes) Sourced from Hartbeespoort Dam in South Africa. Fermentation2023, 9, 685.
Simbayi, T.M.; Rashama, C.; Awosusi, A.A.; Nkuna, R.; Christian, R.; Matambo, T.S. Investigating the Anaerobic Digestion of Water Hyacinth (Eichhornia crassipes) Sourced from Hartbeespoort Dam in South Africa. Fermentation 2023, 9, 685.
Simbayi, T.M.; Rashama, C.; Awosusi, A.A.; Nkuna, R.; Christian, R.; Matambo, T.S. Investigating the Anaerobic Digestion of Water Hyacinth (Eichhornia crassipes) Sourced from Hartbeespoort Dam in South Africa. Fermentation2023, 9, 685.
Simbayi, T.M.; Rashama, C.; Awosusi, A.A.; Nkuna, R.; Christian, R.; Matambo, T.S. Investigating the Anaerobic Digestion of Water Hyacinth (Eichhornia crassipes) Sourced from Hartbeespoort Dam in South Africa. Fermentation 2023, 9, 685.
Abstract
The biodegradability of water hyacinth for biogas and biofertiliser production was studied under mesophilic conditions. The effects of water hyacinth pre-treatments were also included in this investigation. It was found that water hyacinth has a low biodegradability of 27% when monodigested while at a 3:1 ratio with cow manure, the biodegradability increases to 46%. At this elevated biodegradability, the water hyacinth biomethane potential was 185 LCH4/kgVS, while that of cow manure was 216 LCH4/kgVS. The Gompertz kinetic model had superior parameters than the Logistic model for most of the water hyacinth-cow manure combined substrate digestion. Based on the Gompertz model, the lag phase and daily maximum methane production rate were 5.5 days and 22.9 ml /day respectively for the 3:1 codigestion (R2 of 0.99). These values were 6.7 days and 15.2 ml/day respectively, in the case of water hyacinth monodigestion (R2 = 0.996). The dominant microbial species detected in the digestates were Bacteroidetes and Proteobacteria. A few microbial species were indigenous to water hyacinth but a more diverse consortia which is key to efficient substrate biodegradation, came from cow manure. The digestate contained ammonium nitrogen at 68 mg/kg with phosphorous and potassium at 73 and 424 mg/kg respectively. Nitrogen was lower but phosphorous and pottasium were comparable to previously studied digestates of other substrates. Only water hyacinth pretreated through aerobic composting proved to unlock a higher methane yield that matched a 3:1 codigestion with cow manure. Other pretreatments induced better biodegradation performance than that observed on untreated water hyacinth but this improvements were not as good as that of the 3:1 codigestion scheme. It was concluded that water hyacinth sourced from the Hartbeespoort dam, could be treated through anaerobic digestion to recover biogas and biofertilizer. However, more experiments are required to fully understand and harness the optimisation opportunities available in applying this technology to manage water hyacinth.
Keywords
water hyacinth; cow manure; codigestion; biomethane potential; biofertilizer manure
Subject
Environmental and Earth Sciences, Sustainable Science and Technology
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
