Production of biogas from different organic materials is a most interesting source of renewable energy.The biomethane potential (BMP) of these materials has to be determined to get insight in design parameters for anaerobic digesters. Although several norms and guidelines for BMP tests exist, inter-laboratory tests regularly show high variability of BMPs for the same substrate. A workshop was held in June 2015, in Leysin, Switzerland, with over 40 attendees from 30 laboratories around the world, to agree on common solutions to the conundrum of inconsistent BMP test results. This paper presents the consensus of the intense roundtable discussions and cross-comparison of methodologies used in respective laboratories. Compulsory elements for the validation of BMP results were defined. They include the minimal number of replicates, the request to carry out blank and positive control assays, a criterion for the test duration, details on BMP calculation, and last but not least criteria for rejection of the BMP tests. Finally, recommendations on items that strongly influence the outcome of BMP tests such as inoculum characteristics, substrate preparation, test setup, and data analysis are presented to increase the probability of obtaining validated and reproducible results.

A key element in making our food systems more efficient is the reduction of food losses across the entire food value chain. Nevertheless, food losses are often neglected. This paper quantifies food losses in Switzerland at the various stages of the food value chain (agricultural production, postharvest handling and trade, processing, food service industry, retail, and households), identifies hotspots and analyses the reasons for losses. Twenty-two food categories are modelled separately in a mass and energy flow analysis, based on data from 31 companies within the food value chain, and from public institutions, associations, and from the literature. The energy balance shows that 48% of the total calories produced (edible crop yields at harvest time and animal products, including slaughter waste) is lost across the whole food value chain. Half of these losses would be avoidable given appropriate mitigation measures. Most avoidable food losses occur at the household, processing, and agricultural production stage of the food value chain. Households are responsible for almost half of the total avoidable losses (in terms of calorific content).

Mechanical disintegration - wet milling - was chosen to physically disrupt cellular material. By breaking up microbial or plant cell walls intracellular carbon sources as well as nutrients are made available for further anaerobic digestion. Ball milling consistently showed better disintegration results than high speed cutter milling. With respect to solubilisation of COD a high degree of cell disruption could be achieved in a variety of aerobic and anaerobic sewage sludges, where the fraction of soluble COD could be changed from 1–5% in original sludges to up to 47% after wet milling. In distillery slops and brewery residues milling failed to enhance soluble COD significantly. Anaerobic digestion testing showed a good digestability of the solubilized intracellular material and consistently enhanced overall COD-degradation of the sludges by a factor of 1.2–1.5. Net biogas production was enhanced in the same order of magnitude. Stabilised sludges showed a higher beneficial effect of wet milling than raw excess sludge.

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In order to obtain more detailed information for better decision making in future biogenic waste treatment, different processes to treat biogenic wastes in plants with a treatment capacity of 10,000 tons of organic household wastes per year as well as agricultural codigestion plants were compared by life cycle assessments (LCA). With the tool EcoIndicator, anaerobic digestion is shown to be advantageous as compared to composting, incineration or a combination of digestion and composting, mainly because of a better energy balance. The management of the liquid manure in agricultural codigestion of organic solid wastes causes increased gaseous emissions, which have negative effects on the LCA, however. It is recommended to cover the slurry pit and to use an improved manure management in order to compensate for the additional gaseous emissions. In the LCAs, the quality of the digester output could only be taken into account to a small extent; the reasons are discussed.

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Investigation of the temperature dependence of the eonymph‐pronymph transformation of the spruce webspinning sawfly Cephalcia abietis L. (Hym., Pamphiliidae) The larvae of the Spruce Webspinning Sawfly, Cephalcia abietis L., a pest infesting old spruce stands, show very different diapause behaviour. The different diapause in the eonymph stages causes a differing generation‐development duration (1–3 years) which renders difficult a prognosis of the hatching time. The present study was carried out in order to estimate the temperature dependency of the development of the eonymph‐pronymph transformation. Zusammenfassung Die Eonymphen‐Pronymphen Umwandlung der Fichtengespinstblattwespe Cephalcia abietis L. ist von der Temperatur abhängig. Erst ab Temperaturen von 13°C entwickeln sich Eonymphen unter Laborbedingungen zum Pronymphenstadium P4 weiter. Die optimale Entwicklungstemperatur liegt dabei zwischen 13°C und 22°C. Die Entwicklungsdauer dieses Umwandlungsprozesses wird wesentlich vom Zeitpunkt der Probeentnahme der Eonymphen im Freiland bestimmt. Eine Verpuppung der Pronymphen erfolgte erst nach einer Wintersimulation von mindestens 2 Monaten bei Temperaturen von — 1°C. Die Dauer des Überliegens bei der Fichtengespinstblattwespe wird nach den vorliegenden Untersuchungen durch den Temperaturverlauf gesteuert.