|CAMARENA-MARTINEZ, SARAI - University Of Guanajuato|
|MARTINEZ-MARTINEZ, JUAN - University Of Guanajuato|
|SALDANA-ROBLES, ADRIANA - University Of Guanajuato|
|NUNEZ-PALENIUS, HECTOR - University Of Guanajuato|
|COSTILLA-SALAZAR, ROGELIO - University Of Guanajuato|
|VALDEZ-VAZQUEZ, INDANIA - The National Autonomous University Of Mexico|
|RUIZ-AGUILAR, GRACIELA - University Of Guanajuato|
Submitted to: BioResources
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/29/2020
Publication Date: 5/7/2020
Citation: Camarena-Martinez, S., Martinez-Martinez, J.H., Saldana-Robles, A., Nunez-Palenius, H.G., Costilla-Salazar, R., Valdez-Vazquez, I., Lovanh, N.C., Ruiz-Aguilar, G. 2020. Effects of experimental parameters on methane production and volatile solids removal from tomato and pepper plant wastes. BioResources. 15(3):4763-4780.
Interpretive Summary: Millions of tons of crop residues are generated each year around the world after harvest. These crop residues would just be left in the fields and wasted. Thus, alternative waste management and treatment are necessary. These crop residues could be utilized as feedstock for renewable energy in the form of biogas production from anaerobic digestion. Anaerobic digestion of agricultural wastes can serve as an alternative waste treatment practice that could reduce biomass and generate energy for on-farm use. However, bioenergy production from agricultural wastes may be difficult since these wastes are recalcitrant to anaerobic digestion. Therefore, a thorough understanding of anaerobic digestion agricultural wastes is needed. A study was carried out to examine the effects of various parameters relating to the operation and the optimization of bioenergy production from edible crop residues such as tomato and pepper plants. The results show that acclimated culture of bacteria and the correct ratios of feedstock are needed for optimal biogas production. Furthermore, additional carbon source, whether by mixing different feedstock, along with the correct ranges of pH and temperature help improve the biogas production. Thus, it is very important to consider various biochemical factors when designing and operating an anaerobic digester for optimizing biogas production, especially from non-traditional waste feedstock such as mixed crop residues.
Technical Abstract: In Mexico, protected agriculture generates large amounts of tomato and pepper plants residues (TPW and PPW, respectively). Given the limited information on methane production from these wastes, this study aims to determine the effects of the substrate/inoculum (S/I) ratio, temperature and total solids content on methane production and volatile solids removal by two subsequent batch experiments (Experiments A and B). Experiment A was performed to evaluate substrate/inoculum ratios of 0.5, 1.0, and 2.0 at room temperature (22 ± 4.5 °C). Based on the best methane yield a new experiment was established (Experiment B) using only tomato wastes, where temperature were tested at 29 and 39 °C and total solid content analyzed depended on the S/I ratio used. For both substrates, S/I ratio of 0.5 was the most appropriate for methane production. The temperature had a positive effect on volatile solids removal and methane yield. In contrast, the total solid content (% TS) only had a positive effect on methane production. To our knowledge, this is the first study evaluating the effect of the S/I ratio on methane production from tomato and pepper plant wastes.