Datasets on material properties and energy yields of lab-designed organic fraction of municipal solid waste (OFMSW) components.

The organic fraction of municipal solid waste (OFMSW) is a complex material with different ingredients characterized by varying properties depending on parameters such as season or geographical region of origin. Consequently, studies on OFMSW are hard to compare due to the changing characteristics of the samples. Therefore, this article presents data on the physico-chemical composition of standardized, recipe-based OFMSW components divided into the categories "Paper", "Green waste" and "Food waste", and further subcategories. Data presented in this article include (1) dry matter, (2) organic dry matter, (3) C, H and N concentrations, (4) gross calorific values, (5) ash melting behavior, (6) specific biogas yield and (7) methane concentration. An application example of an experiment requiring the same starting material properties is represented by storage experiments, as performed within the original scientific article [1]. Thus, this Data in Brief article also provides additional data on recipe-based storage experiments complementing the original article. The datasets cannot only be used to estimate biowaste potentials but they can also be used for the design and execution of experiments that require standardized OFMSW samples.

Improving the energetic utilization of household food waste: Impact of temperature and atmosphere during storage.

Food waste (FW) from households represents a major fraction of municipal waste and it is often collected in separate biowaste bins. Until waste collection is carried out, storage conditions in the biowaste bin influence FW properties. To draw conclusions for an optimized waste utilization in anaerobic digestion (AD), the aim of this study was to evaluate the impact of storage duration (20 to 40 days) and temperature (5 °C and 20 °C) on inherent energy potentials of household FW during aerobic and anaerobic storage. Therefore, physico-chemical parameters of recipe-based FW samples with reproducible initial compositions were monitored. After 20 days of aerobic storage, water contents (WC) were reduced from 61.9% to 39.5% (20 °C) and from 63.9% to 50.3% (5 °C) while organic dry matter (oDM) concentrations were lowered by 4.3% (20 °C) and 1.1% (5 °C). Increased pH-values of 6.6 (initially 5.5) were only measured for FW stored aerobically at 20 °C. In total, the energy potential was decreased by 31% (20 °C) and by 16% (5 °C). Thus, storage temperature and duration are crucial parameters for optimized aerobic FW storage leading to higher energy yields in AD. Instead, anaerobic storage of FW decreased pH-values to <5 while increasing WC in all samples (up to 67% at 20 °C). As oDM concentrations were preserved almost completely, the energy potential losses were only marginal proving that energy contents of FW could be preserved at household level. Consequently, energy yields in AD of FW could be increased through anaerobic storage conditions.

How closely does stem growth of adult beech (Fagus sylvatica) relate to net carbon gain under experimentally enhanced ozone stress?

The hypothesis was tested that O(3)-induced changes in leaf-level photosynthetic parameters have the capacity of limiting the seasonal photosynthetic carbon gain of adult beech trees. To this end, canopy-level photosynthetic carbon gain and respiratory carbon loss were assessed in European beech (Fagus sylvatica) by using a physiologically based model, integrating environmental and photosynthetic parameters. The latter were derived from leaves at various canopy positions under the ambient O(3) regime, as prevailing at the forest site (control), or under an experimental twice-ambient O(3) regime (elevated O(3)), as released through a free-air canopy O(3) fumigation system. Gross carbon gain at the canopy-level declined by 1.7%, while respiratory carbon loss increased by 4.6% under elevated O(3). As this outcome only partly accounts for the decline in stem growth, O(3)-induced changes in allocation are referred to and discussed as crucial in quantitatively linking carbon gain with stem growth.

Seasonal patterns of carbon allocation to respiratory pools in 60-yr-old deciduous (Fagus sylvatica) and evergreen (Picea abies) trees assessed via whole-tree stable carbon isotope labeling.

• The CO(2) efflux of adult trees is supplied by recent photosynthates and carbon (C) stores. The extent to which these C pools contribute to growth and maintenance respiration (R(G) and R(M), respectively) remains obscure. • Recent photosynthates of adult beech (Fagus sylvatica) and spruce (Picea abies) trees were labeled by exposing whole-tree canopies to (13) C-depleted CO(2). Label was applied three times during the year (in spring, early summer and late summer) and changes in the stable C isotope composition (δ(13) C) of trunk and coarse-root CO(2) efflux were quantified. • Seasonal patterns in C translocation rate (CTR) and fractional contribution of label to CO(2) efflux (F(Label-Max)) were found. CTR was fastest during early summer. In beech, F(Label-Max) was lowest in spring and peaked in trunks during late summer (0.6 ± 0.1, mean ± SE), whereas no trend was observed in coarse roots. No seasonal dynamics in F(Label-Max) were found in spruce. • During spring, the R(G) of beech trunks was largely supplied by C stores. Recent photosynthates supplied growth in early summer and refilled C stores in late summer. In spruce, CO(2) efflux was constantly supplied by a mixture of stored (c. 75%) and recent (c. 25%) C. The hypothesis that R(G) is exclusively supplied by recent photosynthates was rejected for both species.

Seasonal dynamics in the stable carbon isotope composition δ¹³C from non-leafy branch, trunk and coarse root CO2 efflux of adult deciduous (Fagus sylvatica) and evergreen (Picea abies) trees.

Respiration is a substantial driver of carbon (C) flux in forest ecosystems and stable C isotopes provide an excellent tool for its investigation. We studied seasonal dynamics in δ¹³C of CO2 efflux (δ¹³C(E)) from non-leafy branches, upper and lower trunks and coarse roots of adult trees, comparing deciduous Fagus sylvatica (European beech) with evergreen Picea abies (Norway spruce). In both species, we observed strong and similar seasonal dynamics in the δ¹³C(E) of above-ground plant components, whereas δ¹³C(E) of coarse roots was rather stable. During summer, δ¹³C(E) of trunks was about -28.2‰ (Beech) and -26.8‰ (Spruce). During winter dormancy, δ¹³C(E) increased by 5.6-9.1‰. The observed dynamics are likely related to a switch from growth to starch accumulation during fall and remobilization of starch, low TCA cycle activity and accumulation of malate by PEPc during winter. The seasonal δ¹³C(E) pattern of branches of Beech and upper trunks of Spruce was less variable, probably because these organs were additionally supplied by winter photosynthesis. In view of our results and pervious studies, we conclude that the pronounced increases in δ¹³C(E) of trunks during the winter results from interrupted access to recent photosynthates.