Source Reduction and the Waste Management Hierarchy

Source reduction and the waste management hierarchy have become the subject of considerable controversy. This paper describes the two extreme positions on source reduction and places them in context in the debate on how to better manage waste. It uses case studies to illustrate that the polar positions are ideological and that such simplistic views lead to inaction. It argues for compromise positions and emphasizes that improved hazardous substances management will come about not through further debate but through implementing solutions on a case-by-case basis. Some measures may prove appropriate only for certain plants and operations; other measures may apply across an entire industry.     

Survival of weed seeds and animal parasites as affected by anaerobic digestion at meso- and thermophilic conditions

Anaerobic digestion of residual materials from animals and crops offers an opportunity to simultaneously produce bioenergy and plant fertilizers at single farms and in farm communities where input substrate materials and resulting digested residues are shared among member farms. A surplus benefit from this practice may be the suppressing of propagules from harmful biological pests like weeds and animal pathogens (e.g. parasites). In the present work, batch experiments were performed, where survival of seeds of seven species of weeds and non-embryonated eggs of the large roundworm of pigs, Ascaris suum, was assessed under conditions similar to biogas plants managed at meso- (37 °C) and thermophilic (55 °C) conditions. Cattle manure was used as digestion substrate and experimental units were sampled destructively over time. Regarding weed seeds, the effect of thermophilic conditions (55 °C) was very clear as complete mortality, irrespective of weed species, was reached after less than 2 days. At mesophilic conditions, seeds of Avena fatua, Sinapsis arvensis, Solidago canadensis had completely lost germination ability, while Brassica napus, Fallopia convolvulus and Amzinckia micrantha still maintained low levels (～1%) of germination ability after 1 week. Chenopodium album was the only weed species which survived 1 week at substantial levels (7%) although after 11 d germination ability was totally lost. Similarly, at 55 °C, no Ascaris eggs survived more than 3 h of incubation. Incubation at 37 °C did not affect egg survival during the first 48 h and it took up to 10 days before total elimination was reached. In general, anaerobic digestion in biogas plants seems an efficient way (thermophilic more efficient than mesophilic) to treat organic farm wastes in a way that suppresses animal parasites and weeds so that the digestates can be applied without risking spread of these pests.     

Energy or compost from green waste? – A CO2 – Based assessment

Green waste is increasingly extracted from the material recycling chain and, as a result of the financial subsidy arising from the German renewable energy law for the generation of energy from renewable raw materials; it is fed into the energy recovery process in biomass power stations. A reduction in climate relevant gases is also linked to the material recovery of green waste – in particular when using composts gained from the process as a new raw material in different types of potting compost and plant culture media as a replacement for peat. Unlike energy recovery, material valorisation is not currently subsidised. Through the analysis of material and energy valorisation methods for green waste, with particular emphasis on primary resource consumption and CO₂-balance, it could be determined that the use of green waste for energy generation and its recovery for material and peat replacement purposes can be considered to be on a par. Based on energy recovery or material oriented scenarios, it can be further deduced that no method on its own will achieve the desired outcome and that a combination of recycling processes is more likely to lead to a significant decrease of greenhouse gas emissions.     

Enhancing Conservation,Ecosystem Services,and Local Livelihoods through a Wildlife Premium Mechanism

We propose the wildlife premium mechanism as an innovation to conserve endangered large vertebrates. The performance‐based payment scheme would allow stakeholders in lower‐income countries to generate revenue by recovering and maintaining threatened fauna that can also serve as umbrella species (i.e., species whose protection benefits other species with which they co‐occur). There are 3 possible options for applying the premium: option 1, embed premiums in a carbon payment; option 2, link premiums to a related carbon payment, but as independent and legally separate transactions; option 3, link premiums to noncarbon payments for conserving ecosystem services (PES). Each option presents advantages, such as incentive payments to improve livelihoods of rural poor who reside in or near areas harboring umbrella species, and challenges, such as the establishment of a subnational carbon credit scheme. In Kenya, Peru, and Nepal pilot premium projects are now underway or being finalized that largely follow option 1. The Kasigau (Kenya) project is the first voluntary carbon credit project to win approval from the 2 leading groups sanctioning such protocols and has already sold carbon credits totaling over $1.2 million since June 2011. A portion of the earnings is divided among community landowners and projects that support community members and has added over 350 jobs to the local economy. All 3 projects involve extensive community management because they occur on lands where locals hold the title or have a long‐term lease from the government. The monitoring, reporting, and verification required to make premium payments credible to investors include transparent methods for collecting data on key indices by trained community members and verification of their reporting by a biologist. A wildlife premium readiness fund would enable expansion of pilot programs needed to test options beyond those presented here. Mejora de la Conservación, Servicios del Ecosistema y Calidad de Vida Local Mediante un Mecanismo de Compensación de Vida Silvestre     

A comprehensive action determination model: Toward a broader understanding of ecological behaviour using the example of travel mode choice

This paper examines a first version of a Comprehensive Action Determination Model (CADM) of ecological behaviour that incorporates intentional, normative, situational, and habitual influences on environmentally friendly behaviour. The main assumptions of the theory of planned behaviour (TPB), the norm-activation model (NAM), the theoretical concept of habit and the ipsative theory of behaviour were integrated into a comprehensive model. The model was tested using a structural equation modelling approach on a sample of 389 students in the domain of travel mode choice and compared to established less comprehensive models (TPB, NAM and a combination of both). The results show that all compared models had a good to excellent model fit and explained a substantial amount of variation in travel mode choice. The CADM, however, explained the greatest degree of variation as compared with the other models, at 65%. Subjective and objective situational constraints were responsible for most of the variation in travel mode choice in the CADM, but intentions and habits also had a significant impact. The influence of social and personal norms was mediated by habits and intention, while habits moderated the relationship between intention and behaviour. The importance of the CADM as a framework for other domains of ecological behaviour is also discussed.     

Validating a Safety Climate Model in Metal Processing Industries: A Replication Study

This paper attempts to replicate a safety climate model originally tested in Australia to assess its applicability in a different context: namely, across production workers in 22 medium-sized metal processing organizations in Austria. The model postulates that safety knowledge and safety motivation mediate the relation between safety climate on the one hand and safety compliance and participation on the other. Self-report data from 1075 employees were analyzed using structural equation modeling (SEM). The results of the replication study largely confirmed the original safety climate model. However, in addition to indirect effects, direct links between safety climate and actual safety behavior were found.     

Foraging in groups of water striders (Gerris remigis): effects of variability in prey arrivals and handling times

Summary In many species, socially subordinate individuals frequently remain in a group despite their lower priority of access to food and mates. This is expected to occur when the net benefits of staying in the group exceed those of a solitary existence. Analogously, territorial foragers surrounded by conspecific competitors are faced with tradeoffs as to patch tenacity. In either case, spatio-temporal variability in resource availability directly affects behavioral patterns and payoffs, particularly of individuals with low priority of access to the resource. However, such individuals may take advantage of natural environmental fluctuations in resource supply in cases where dominants are preoccupied. This arises regularly if two resource items cannot be handled simultaneously and if a second item arrives before handling of the first has been completed. I advance a heuristic model that predicts that foraging or mating success of individuals with low priority of access to resources may increase both with higher variance in inter-arrival times of the resource (given the same mean) and with an increase in the average handling time of the resource. I tested both predictions with two associations of individually marked, naturally foraging water striders (Gerris remigis) in the field. In natural streams individual water striders tend to occupy consistent positions that they may defend, resulting in priority of access to prey items floating downstream for individuals further up front. I manipulated the variance in prey inter-arrival times given the same mean, and the prey handling times by offering larger prey. The outcome was in qualitative agreement with the predictions of the model.