Research priorities for managing the impacts and dependencies of business upon food,energy, water and the environment

Delivering access to sufficient food, energy and water resources to ensure human wellbeing is a major concern for governments worldwide. However, it is crucial to account for the ‘nexus’ of interactions between these natural resources and the consequent implications for human wellbeing. The private sector has a critical role in driving positive change towards more sustainable nexus management and could reap considerable benefits from collaboration with researchers to devise solutions to some of the foremost sustainability challenges of today. Yet opportunities are missed because the private sector is rarely involved in the formulation of deliverable research priorities. We convened senior research scientists and influential business leaders to collaboratively identify the top forty questions that, if answered, would best help companies understand and manage their food-energy-water-environment nexus dependencies and impacts. Codification of the top order nexus themes highlighted research priorities around development of pragmatic yet credible tools that allow businesses to incorporate nexus interactions into their decision-making; demonstration of the business case for more sustainable nexus management; identification of the most effective levers for behaviour change; and understanding incentives or circumstances that allow individuals and businesses to take a leadership stance. Greater investment in the complex but productive relations between the private sector and research community will create deeper and more meaningful collaboration and cooperation.     

A Method of Predicting Point and Path- Averaged Ambient Air VOC Concentrations,Using Meteorological Data

A method of predicting point and path-averaged ambient air VOC concentrations is described. This method was developed for the case of a plume generated from a single point source, and is based on the relationship between wind directional frequency and concentration. One-minute means of wind direction and wind speed were used as inputs to a Gaussian dispersion model to develop this relationship.

Both FTIR spectrometry and a whole-air sampling method were used to monitor VOC plumes during simulated field tests. One test set was also conducted using only whole-air samplers deployed in a closely-spaced network, thus providing an evaluation of the prediction technique free of any bias that might exist between the two analytical methods.

Correlations between observed point concentrations and wind directional frequencies were significant at the 0.05 level in most cases. Predicted path-integrated concentrations, based on observed point concentrations and meteorological data, were strongly correlated with observed values. Predicted point concentrations, based on observed path-integrated concentrations and meteorological data, accurately reflected the location and magnitude of the highest concentrations from each test, as well as the shape of the concentration-versus-crosswind distance curve.     

A Qualitative Analysis of the Effects of Water Vapor on Multi-Component Vapor-Phase Carbon Adsorption

The effects of water vapor on binary vapor adsorption of toluene and methylene chloride by activated carbon were investigated on a bench-scale experimental system. Three levels of relative humidity (15, 65 and 90 percent) in conjunction with different concentrations of individual adsorbates (from 400 to 1200 ppmv) were tested by tracing the breakthrough curves of each adsorbate eluted from a fixed-bed adsorber. The adsorption capacities of the activated carbon tested for each adsorbate under the various conditions were obtained from calculations based on area integration of the breakthrough curves. It was found that with increasing relative humidity, the shape of breakthrough curves was asymmetrically distorted and the width of the breakthrough curves was broadened for toluene and steepened for methylene chloride. The adsorption capacities for both toluene and methylene chloride were decreased with the increase of relative humidity. The magnitude of the effect of water vapor is greater at the lower toluene concentration and at the higher concentration of methylene chloride. The mechanisms of water vapor influence on the process of multicomponent vapor adsorption are discussed.     

In situ ammonia removal in bioreactor landfill leachate

Although bioreactor landfills have many advantages associated with them, challenges remain, including the persistence of NH(3)-N in the leachate. Because NH(3)-N is both persistent and toxic, it will likely influence when the landfill is biologically stable and when post-closure monitoring may end. An in situ nitrogen removal technique would be advantageous. Recent studies have shown the efficacy of such processes; however, they are lacking the data required to enable adequate implementation at field-scale bioreactor landfills. Research was conducted to evaluate the kinetics of in situ ammonia removal in both acclimated and unacclimated wastes to aid in developing guidance for field-scale implementation. Results demonstrate that in situ nitrification is feasible in an aerated solid waste environment and that the potential for simultaneous nitrification and denitrification (even under low biodegradable C:N conditions) in field-scale bioreactor landfills is significant due to the presence of both aerobic and anoxic areas. All rate data fit well to Monod kinetics, with specific rates of removal of 0.196 and 0.117 mgN/day-g dry waste and half-saturation constants of 59.6 and 147 mgN/L for acclimated and unacclimated wastes, respectively. Although specific rates of ammonia removal in the unacclimated waste are lower than in the acclimated waste, a relatively quick start-up of ammonia removal was observed in the unacclimated waste. Using the removal rate expressions developed will allow for estimation of the treatment times and volumes necessary to remove NH(3)-N from recirculated landfill leachate.     

MODEL FOR PREDICTING TRANSPORT OF PESTICIDES AND THEIR METABOLITES IN THE UNSATURATED ZONE1

ABSTRACT: A finite element model based on Galerkin's upstream weighted residual technique was developed to predict the simultaneous convective-dispersion transport and transformations of pesticides and their metabolites in the unsaturated zone. Transformations of the parent compound and its metabolites were assumed to be first-order reactions for oxidation and hydrolysis, while adsorption of the pesticide species (parent compound and metabolites) to the soil components was assumed to be represented by a linear equilibrium (Freundlich type) isotherm. Volatilization and plant root uptake of pesticides in the solution phase were neglected in the analysis. The proposed model was used to simulate the transport and transformation of aldicarb and its metabolites, aldicarb sulfoxide and aldicarb sulfone, in the soil profile. Several examples are used to demonstrate the accuracy, validity, and applicability of the proposed model. Simulated results indicate that the proposed model can potentially be used to estimate the mass flux of water, and pesticide and pesticide metabolite concentrations in the subsurface environment. However, further verification of the model against actual field data is needed to fully demonstrate the model's potential.     

Determining regional water quality patterns and their ecological relationships

A multivariate statistical method for analyzing spatial patterns of water quality in Georgia and Kansas was tested using data in the US Environmental Protection Agency's STORET data system. Water quality data for Georgia and Kansas were organized by watersheds. We evaluated three questions: (a) can distinctive regional water quality patterns be detected and predicted using only a few water quality variables, (b) are regional water quality patterns correlated with terrestrial biotic regions, and (c) are regional water quality patterns correlated with fish distributions? Using existing data, this method can distinguish regions with water quality very different from the average conditions (as in Georgia), but it does not discriminate well between regions that do not have diverse water quality conditions (as in Kansas). Data that are spatially and temporally adequate for representing large regions and for multivariate statistical analysis are available for only a few common water quality parameters. Regional climate, lithology, and biotic regimes all have the potential to affect water quality, and terrestrial biotic regions and fish distributions do compare with regional water quality patterns, especially in a state like Georgia, where watershed characteristics are diverse. Thus, identifiable relationships between watershed characteristics and water quality should allow the development of an integrated landaquatic classification system that would be a valuable tool for resource management. Because geographical distributions of species may be limited by Zoogeographic and environmental factors, the recognition of patterns in fish distributions that correlate with regional water quality patterns could influence management strategies and aid regional assessments.     

Roles of land use resolution and unit-area load rates in assessment of diffuse nutrient emissions

In contrast to its counterparts in Europe and North America, the Australian National Pollutant Inventory (NPI) includes estimates of aggregated emissions of nutrients (total nitrogen and total phosphorus) from catchments and facilities. Sparse or inadequate data limit the extent to which nutrient exports may be estimated from direct observations. The paucity of data for calibration and simulation limits the use of sophisticated models in most Australian catchments. Therefore, a simple unit-area load model-Catchment Management Support System (CMSS)-was selected to estimate aggregated catchment emissions for the NPI. Estimates from models like CMSS are sensitive to spatial and categorical resolution of land uses identified within the catchment and to nutrient generation rates selected for each land use category. Using three Hawkesbury-Nepean subcatchments, we show that while high spatial resolution of land use mapping is useful, only four or five major land use categories with carefully selected generation rates were required to estimate potential nutrient exports sufficiently well and to determine subcatchments contributing most. Nutrient emission estimates proved to be highly dependent on selection of generation rates so a bootstrap technique was adopted to reduce subjectivity and to improve estimates of confidence limits. This led to a specification of new generation rates for Natural, Unimproved pasture, Rural and Urban land uses and to establishment of uncertainty limits.