An assessment of anaerobic thermophilic co-digestion of dairy cattle manure and separated tomato greenhouse waste lab-scale reactors

Abstract

Anaerobic co-digestion of dairy cow manure (DCM) and separated tomato greenhouse waste (tomato stalks and leaves (TSL) and rotten and damaged tomato fruits - TF) was conducted under batch thermophilic conditions (T = 55 °C) for period of 45 days. Concentrations of substrates (tomato waste) were 5 and 10% (w/v). Each substrate, as well as experimental mixtures, was analysed order to specify the content of pH, total solids (TS), volatile solids (VS), total extractable nitrogen (TN) and total organic carbon (TOC). Biogas yield and composition, as well as cumulative biogas curves, were reported. comparison to DCM monodigestion (329.5 cm3·g-1 VS), biogas yield was significantly improved experiment C (365.1 cm3·g-1 VS) (with 5% (w/v) TF added), whereas methane yield did not show any significant difference. Experiment D (with 10% (w/v) TSL added) resulted significantly lower biogas and methane yields contrast to the rest of experiments performed. Average methane content all analysed experimental samples ranged from 65 to 69%. It is evident from the results that biogas production can be improved by addition of separated tomato greenhouse waste to DCM process and issue of organic waste disposal could be effectively solved.