Residual municipal solid waste as co-substrate at wastewater treatment plants: An assessment of methane yield, dewatering potential and microbial diversity.

Separately collected organic fraction of municipal solid waste, also known as biowaste, is typically used to fill the available capacity of digesters at wastewater treatment plants. However, this approach might impair the use of the ensuing digestate for fertilizer production due to the presence of sewage sludge, a contaminated substrate. Worldwide, unsorted municipal solid household waste, i.

The economic efficiency of the co-digestion at WWTPs: A full-scale study.

The methane and digestate production from biowaste (BW, 95% food waste and 5% garden waste based on fresh mass) and grease trap sludge (GTS) co-digestion at the Grossache-Nord WWTP (Austria) as a basis for a cost-benefit analysis was determined using two approaches: The first one was to determine the specific methane yields (SMY) and total solids (TS) removals (%) of the used substrates in biomethane potential (BMP) tests. In the second, the full-scale process data from a supervisory control and data acquisition (SCADA) system were analyzed. From these data, the SMY of the sewage sludge (SS) was calculated for a period without co-digestion and applied to the study period.

Determination of the dewatered digestate amounts and methane yields from the co-digestion of biowaste as a basis for a cost-benefit analysis.

Co-digestion is the simultaneous digestion of two or more substrates and a common practice at wastewater treatment plants (WWTPs). The amounts of methane and digested sludge produced are key parameters for evaluating the economic efficiency of co-digestion. However, the share of dewatered digestate produced from co-substrates is not known.

Mechanical separation of impurities in biowaste: Comparison of four different pretreatment systems.

Impurities in biowaste, such as plastics, glass, metals and inert material, negatively impact the operation of anaerobic digestion plants and compost quality, and have to be removed prior to the anaerobic digestion process. Different mechanical pretreatments are available for this purpose. However, data on the removal efficiencies of pretreatment systems for different types of biowaste and for different kinds of impurities are still scarce.

Comparison of two mechanical pre-treatment systems for impurities reduction of source-separated biowaste.

The treatment of source-separated biowaste is still a challenge due to its high proportion of impurities. Biowaste bins are intended exclusively for the collection of biodegradable matter, such as food, kitchen and garden waste. However, plastics, metals, glass and textiles are also found in biowaste bins.

Reducing the life cycle GHG emissions of microalgal biodiesel through integration with ethanol production system.

Despite environmental benefits of algal-biofuels, the energy-intensive systems for producing microalgae-feedstock may result in high GHG emissions. Trying to overcome energy-costs, this research analyzed the biodiesel production system via dry-route, based on Chlorella vulgaris cultivated in raceways, by comparing the GHG-footprints of diverse microalgae-biodiesel scenarios. These involved: the single system of biomass production (C0); the application of pyrolysis on the residual microalgal biomass (cake) from the oil extraction process (C1); the same as C0, with anaerobic cake co-digested with cattle manure (C2); the same conditions as in C1 and C2, by integrating in both cases (respectively C3 and C4), the microalgae cultivation with an autonomous ethanol distillery.