Kinetic analysis of methane production from anaerobic digestion of water lettuce (Pistia stratiotesL.) with waste sludge

Abstract

BACKGROUND Increasing demand on energy sources has motivated research studies on renewable energy originating from biomass. Water lettuce (Pistia stratiotes L.) as an invader lignocellulosic biomass with high crop yield can be utilized in anaerobic digestion to produce biomethane. Substrate and inoculum concentrations, and temperature are important parameters for kinetic analysis of methane production that was performed with water lettuce and waste sludge for the first time. Kinetic analysis can be used in reactor design, scale up and identification of optimum conditions. RESULTS In the present study, anaerobic digestion of water lettuce with waste sludge as inoculum was performed in a batch system. Substrate concentration [30, 40 and 50 g total solid (TS) L−1], waste sludge concentration (3.4 and 6.8 g TS L−1) were investigated at different digestion temperatures (35, 45, 55 and 65 °C). In the studied range, the highest biogas yield [321 mL g–1 volatile solid (VS) with 72.5% of methane content) was reached at substrate concentration of 30 g TS L−1 and waste sludge concentration of 6.8 g TS L−1 at 35 °C. The Cone model fitted well to the actual methane production compared to the modified Gompertz model. The effect of digestion temperature on methane production potential was described by the Ratkowsky model (R2 = 0.91) and optimum digestion temperature was found as 45 °C. Experimental methane yields were 81.5–232.7 mL methane g–1 VS which were 27.7–79.0% of theoretical maximum methane yield. Energy conversion efficiency was reached up to 78.4%. CONCLUSION The results revealed that anaerobic digestion of water lettuce with waste sludge for high methane production rate was accomplished at certain substrate and inoculum concentrations and temperature. © 2019 Society of Chemical Industry

Anaerobic Degradation of Environmentally Hazardous Aquatic Plant Pistia stratiotes and Soluble Cu(II) Detoxification by Methanogenic Granular Microbial Preparation

“…Mechanical removal of these plants is widespread [9], but later they begin to rot on the riverbank and again contaminate ecosystems with toxic microbial exometabolites such as fatty acids an alcohols. However, the biomass of pistia is a natural carbohydrate-containing polymer [16]. Therefore, we assumed that the polymers of pistia, like cellulose and starch, could be fermented via anaerobic microorganisms with the formation of CH 4 [16].…”

“…However, the biomass of pistia is a natural carbohydrate-containing polymer [16]. Therefore, we assumed that the polymers of pistia, like cellulose and starch, could be fermented via anaerobic microorganisms with the formation of CH 4 [16]. The use of other polymeric substrates to produce biomethane is also widespread.…”

“…Pistia biomass, however, can be seen as a valuable raw material, the effective use of which can not only reduce the cost of combating this invasive species, but also bring profits. Microbial degradation to produce biogas is one of the useful applications of plant biomass [16,37], which can be used on farms. Its incineration to convert into electricity is another application, but a more hazardous one [38].…”

“…Thus, cop genes, chaperones, transporters, and sequestering molecules together encode copper removal mechanisms in different microorganisms [60]. Microbial biotechnology is economically viable because cheap organic substrates, including environmentally hazardous organic waste, which also includes the aquatic plant Pistia stratiotes L., can be used as a substrate for the growth of microorganisms [16]. Such promising integrated biotechnological approaches based on the simultaneous solution of several environmental problems are poorly studied and require significant fundamental and applied research.…”

Leachate recirculation effects on solid‐state anaerobic digestion of Pennisetum hybrid and microbial community analysis

“…Due to its contribution to the generation of renewable energy, and associated reduction of negative environmental impacts, biogas production has steadily increased . Increasing demands for bioenergy have resulted in an increase in demand for crops which have high yields and low costs, providing reliable and sustainable biomass feedstock (termed energy crops), as well as other alternatives for biomass sources . Due to advantages such as having high abundance, suitable biomass quality and positive environment effects, perennial grasses are widely used in biogas production .…”