Life cycle assessment of using laser treatment and nanomaterials to produce biogas through anaerobic digestion of slurry

Recently, laser radiation and nanomaterials have been utilized to improve biogas yield via anaerobic digestion of herd’s manure through biostimulating methanogenic bacteria. Yet, laser irradiation and nanomaterials as anaerobic bacteria stimulant could have environmental impacts that have not been assessed or known. The aim of the current research was to understand and evaluate variable laser doses in the presence of nickel nanoparticles (Ni NPs) and their environmental impacts during the production of biogas from treated manure. A life cycle assessment scheme was employed to achieve this aim. The used laser doses were 0.5 h, 1 h and 2 h and correlated to 1-h incandescent light exposure, where all treatments received 2 g/m3 Ni NPs. The outcomes were conferred in the pattern of specific influences for the biogas utilization and production as an energy source. The studied impacts were global warming, greenhouse gas emissions mitigation, acidification, eutrophication, ozone layer depletion, freshwater ecotoxicity and prospective human toxicity. Results revealed that laser irradiation with the addition of Ni NPs during the biostimulation of anaerobic digestion has the least environmental adverse effects when compared to the control group.