STREAM DEPTH SIGNIFICANCE DURING IN‐SITU SEDIMENT OXYGEN DEMAND MEASUREMENTS IN SHALLOW STREAMS

Ninety-one sediment oxygen demand (SOD) samples from six designated sites along the stretch of Lower Rapid Creek, South Dakota, were conducted using an in-situ SOD chamber. Inside the chamber, readings of dissolved oxygen (DO), water temperature, pH, and specific conductance were recorded every minute for more than one hour using the Datasonde 3 Hydrolab. Initial readings of such parameters were recorded for the overlaying water before the deployment of the SOD chamber. Characteristics of the stream conditions, air temperature, barometric pressure, average flow velocity of the stream, depth of the stream, and the flow velocity by the chamber were recorded. Single and multiple linear regression analyses on all parameters indicated that the velocity of the stream is the least critical parameter for SOD in shallow streams

Surface Morphology of Reactive Powder Concrete Containing Soil

Recent studies have revealed that concrete can be used as a media to contain As (arsenic) removed from drinking water. Concrete, which is a composite material, has been effective in solidifying hazardous wastes and contaminated soils. A research project was conducted to study the effects of uncontaminated soil and arsenic contaminated soil on the microstructure of concrete to qualitatively define the mechanisms of the encapsulation of soils containing inorganic material such as arsenic by application of solidification/stabilization technique. This research paper focused on studying the surface morphology of RPC (reactive powder concrete) containing soil

Performance of Reactive Powder Concrete Containing Arsenic

A mixture of arsenic contaminated soil and reactive powder concrete (RPC) was developed to study the ef-fect of arsenic contaminated soil on RPC mortar and the effectiveness of the mortar in containing the con-taminant. The sufficient containment of arsenic contaminated waste products is important to protection of ground and surface water sources. A three phase experiment was designed to study the permeability, absorp-tion coefficients, and Toxicity Characteristic Leaching Procedure (TCLP) leachate concentrations resulting from the application of a range of arsenic concentrations. The results showed that the permeability values for mixes containing different arsenic concentrations did not increase noticeably with adequate curing time. The percentage of absorption slightly increased with increasing arsenic content as did the TCLP leachate concen-trations. Statistical analyses, Analysis of Variance (ANOVA) and Paired T-test, were performed to analyze percent absorption, and TCLP results. Based on the results it was concluded that percent absorption de-creased significantly with increase in curing time. Although, the TCLP concentrations increased with in-creased curing time, the increase was not statistically significant

Encapsulation of Contaminated Soil in Concrete Mortar

A mixture of arsenic-contaminated soil and mortar was developed to study the effect of arsenic-contaminated soil on the strength of mortar and the effectiveness of the mortar in containing the arsenic. Preliminary laboratory analyses were conducted with spiked soil samples to verify percent recovery of the toxicity characteristic leaching procedure (TCLP). Five parameters were chosen for variation during the investigation: amount of contaminated soil (as a weight percentage of sand content), concentration of arsenic in the contaminated soil, water-cement ratio (w/ c), amount of fly ash, and amount of silica fume. Compressive strength tests and TCLP tests were conducted on mortar samples. The test results showed that with the changes in the w/ c, silica fume, and fly ash contents in the presence of arsenic, the compressive strength slightly increased from 7 to 28 to 90 days but did not show any major effect on the TCLP tests. The TCLP results were at the level (3 to 20 ppb) predicted to be established as the Drinking Water Equivalent Level (DWEL) by the United States Environmental Protection Agency (USEPA), indicating that mortar containing arsenic and contaminated soil may be a valid disposal solution

Assessment of the Use of Household Chemicals in Al-Karak Governate, Jordan

The objective of this study was to evaluate the major factors that influence the correctness of household chemical utilization in the Jordanian households. The practices in the use of household chemicals of 1200 women in Al-Karak Governate of the country of Jordan were surveyed through a quantitative questionnaire in 2009. The results were analyzed in population sets grouped by different demographic relationships (i.e., age, level of education, family size, number of working members and geographic location). Analysis of Variation (ANOVA) of the population means based on these groupings was conducted. The results indicated that age, level of education, family size and number of working members were all important and statistically significant factors in the proper use of household chemicals in the study area. The means of the population sets based on geographic distribution did not vary significantly indicating that education on the proper use of household chemicals is needed throughout Jordan

Surface Morphology of Reactive Powder Concrete Containing Soil

Recent studies have revealed that concrete can be used as a media to contain As (arsenic) removed from drinking water. Concrete, which is a composite material, has been effective in solidifying hazardous wastes and contaminated soils. A researchproject was conducted to study the effects of uncontaminated soil and arsenic contaminated soil on the microstructure of concrete to qualitatively define the mechanisms of the encapsulation of soils containing inorganic material such as arsenic by application of solidification/stabilization technique. Thisresearch paper focused on studying the surface morphology of RPC (reactive powder concrete) containing soil

Didymosphenia geminata: Algal blooms in oligotrophic streams and rivers

In recent decades, the diatom Didymosphenia geminata has emerged as nuisance species in river systems around the world. This periphytic alga forms large “blooms” in temperate streams, presenting a counterintuitive result: the blooms occur primarily in oligotrophic streams and rivers, where phosphorus (P) availability typically limits primary production. The goal of this study is to examine how high algal biomass is formed under low P conditions. We reveal a biogeochemical process by which D. geminata mats concentrate P from flowing waters. First, the mucopolysaccaride stalks of D. geminata adsorb both iron (Fe) and P. Second, enzymatic and bacterial processes interact with Fe to increase the biological availability of P. We propose that a positive feedback between total stalk biomass and high growth rate is created, which results in abundant P for cell division. The affinity of stalks for Fe in association with iron-phosphorus biogeochemistry suggest a resolution to the paradox of algal blooms in oliogotrophic streams and rivers

Didymosphenia geminata: Algal blooms in oligotrophic streams and rivers

In recent decades, the diatom Didymosphenia geminata has emerged as nuisance species in river systems around the world. This periphytic alga forms large “blooms” in temperate streams, presenting a counterintuitive result: the blooms occur primarily in oligotrophic streams and rivers, where phosphorus (P) availability typically limits primary production. The goal of this study is to examine how high algal biomass is formed under low P conditions. We reveal a biogeochemical process by which D. geminata mats concentrate P from flowing waters. First, the mucopolysaccaride stalks of D. geminata adsorb both iron (Fe) and P. Second, enzymatic and bacterial processes interact with Fe to increase the biological availability of P. We propose that a positive feedback between total stalk biomass and high growth rate is created, which results in abundant P for cell division. The affinity of stalks for Fe in association with iron-phosphorus biogeochemistry suggest a resolution to the paradox of algal blooms in oliogotrophic streams and rivers

Project Management Is in the Details

It is sometimes the smallest details that can unravel an otherwise well-prepared project. A case study about a city in Ohio that decided to install a storm-water system in a residential neighborhood is used to illustrate this point

Evaluation of a total dissolved solids model in comparison to actual field data measurements in the Cheyenne River, South Dakota, USA

During the summers of 2002 and 2004, in-stream integrated flow and concentration measurements for the total dissolved solids in the Cheyenne River, South Dakota, USA was conducted in order to compare the obtained actual field measurements with the predictions values made by the Bureau of Reclamation in the Environmental Impact Statement. In comparison to the actual field measurements conducted in this study, The Bureau of Reclamation extension of a small database used in the analysis for the impact of operations at the Angostura Unit over the past 50 years and into the future to predict the annual total dissolved solid loadings doesn\u27t represent the actual loading values and various conditions in the study area. Additional integrated flow and concentration sampling is required to characterize the impact of the current Angostura Dam operations and Angostura Irrigation District return flows on the Cheyenne River in different seasons of the year