The comparison study of compost and natural organic matter samples

Sewage sludge is a serious problem facing modern wastewater treatment plants. One of the methods to safely utilize the sludge is through composting and the agricultural use of the final product.In this study the compost samples from municipal sewage sludge are compared to the natural, rich in organic matter samples. Based on physicochemical properties of the material, the maturity indices are obtained to evaluate the quality of organic matter and estimate the similarities between the samples.The study shows that one-dimensional analysis like that based on maturity indices does not provide satisfactory answers concerning the nature of such complex materials. The data set of the analysis naturally possesses a multidimensional character so that the employment of advanced chemometric techniques like cluster analysis show a number of features which were hidden within the ‘data flood’.The major conclusion of this work is that the compost from sewage sludge is similar to peat in the significance of the properties of the organic matter. Moreover, the organic matter of agricultural soil, which is most stable and has been naturally matured over a long period of time, differs substantially from the other samples.     

An Investigation of Errors in Distributed Models' Stream Discharge Prediction Due to Channel Routing

Over the summer of 2015, the National Water Center hosted the National Flood Interoperability Experiment (NFIE) Summer Institute. The NFIE organizers introduced a national‐scale distributed hydrologic modeling framework that can provide flow estimates at around 2.67 million reaches within the continental United States. The framework generates discharges by coupling a given Land Surface Model (LSM) with the Routing Application for Parallel Computation of Discharge (RAPID). These discharges are then accumulated through the National Hydrography Dataset Plus stream network. The framework can utilize a variety of LSMs to provide the runoff maps to the routing component. The results obtained from this framework suggested that there still exists room for further enhancements to its performance, especially in the area of peak timing and magnitude. The goal of our study was to investigate a single source of the errors in the framework's discharge estimates, which is the routing component. The authors substitute RAPID which is based on the simplified linear Muskingum routing method by the nonlinear routing component the Iowa Flood Center have incorporated in their full hydrologic Hillslope‐Link Model. Our results show improvement in model performance across scales due to incorporating new routing methodology.