George P. Korfiatis

Combined effects of anions on arsenic removal by iron hydroxides

Batch experiments were conducted to investigate the combined effects of phosphate, silicate, and bicarbonate on the removal of arsenic from Bangladesh groundwater (BGW) and simulated groundwater by iron hydroxides. The apparent adsorption constants indicated that the affinity of the anions for iron hydroxide sites decreased in the following order arsenate>phosphate>arsenite>silicate>bicarbonate. Phosphate, silicate, and bicarbonate decreased the removal of As(III) even at relatively low concentrations and low surface site coverage. Phosphate (0-0.08 mM), silicate (0-0.8 mM), and bicarbonate (0-14 mM) in separate solutions had none to moderate effects on As(V) removal in a solution containing 6.7 mg/l Fe and 0.3 ppm As(V). In the presence of bicarbonate and silicate the adverse effect of phosphate on As(V) adsorption was magnified. The residual As(V) concentration after iron hydroxide treatment increased from less than 13 microg/l in separate bicarbonate (2.2 mM) and phosphate (0.062 mM) solutions to 110 microg/l in the solution containing both anions. The results suggested the combined effects of phosphate, silicate, and bicarbonate caused the high mobility of arsenic in Bangladesh water.

Treatment of arsenic in Bangladesh well water using a household co-precipitation and filtration system

Laboratory and field tests were conducted to evaluate the effectiveness of a household filtration process and investigate the effects of phosphate and silicate on the removal of arsenic from Bangladesh groundwater by ferric hydroxides. Fe/As ratios of greater than 40 (mg/mg) were required to reduce arsenic to less than 50 microg/L in Bangladesh well water due to the presence of elevated phosphate and silicate concentrations. The household filtration process included co-precipitation of arsenic by adding a packet (approximately 2 g) of ferric and hypochlorite salts to 20 L of well water and subsequent filtration of the water through a bucket sand filter. A field demonstration study was performed to test the treatment system in seven households in Bangladesh in March and April 2000. Experimental results obtained from the participating families proved that the household treatment process removed arsenic from approximately 300 microg/L in the well water to less than 50 microg/L. The participating families liked this simple and affordable process and used it to prepare clean water for drinking and cooking. A larger scale field test is currently underway.

Removal of selenocyanate from water using elemental iron

Batch experiments were conducted to investigate the removal of selenocyanate (SeCN-) from oil refinery wastewater and artificial wastewater with elemental iron [Fe(0)]. The chemical forms of selenium in the reacted solids were determined with X-ray photoelectron spectroscopy (XPS) and a sulfite extraction procedure. SeCN- was effectively removed from the wastewater with Fe(0) filings when the water pH was controlled at approximately 6. SeCN- was removed by Fe(0) through the formation of elemental selenium [Se(0)] and ferrous selenide. The possible chemical reactions between SeCN- and Fe(0) included deselenation of SeCN- and electrochemical reduction of Se(0) to selenide. A cost-effective process may be developed for the treatment of SeCN- in wastewater using Fe(0).

Biodegradation of diphenylamine by selected microbial cultures

Abstract The degradation of diphenylamine (DPA) by pure Pseudomonas (P. cepacia, P. putida, P. resinovorans) and mixed activated sludge cultures in batch shaker flasks and bioreactor systems is described. The experiments were carried out at initial DPA concentrations in the range of 15–60 mg/l. Under the experimental conditions, all cultures were capable of degrading DPA, as a sole carbon source, at comparable rates. Addition of glucose as a co‐substrate was found not to have an effect on the apparent biodegration rates. In the range of initial substrate concentrations attempted in this study, the DPA biodegradation rate was found to follow first‐order kinetics. In bioreactor experiments, the biodegradation rate constant (kl) was determined to be 0.54 d‐1 corresponding to a half‐life (t½) 1.40 days. The effect of these findings on the storage stability of nitrocellulose based propellant formulations are discussed.

Sonochemical extraction and biological treatment of pentachlorophenol contaminated wood

Abstract More than 450 million cubic feet of pentachlorophenol (PCP) treated wood products are discarded in municipal landfills or burned in power generating plants in the USA alone. The reported carcinogenicity of PCP is expected to result in more stringent controls and limit the disposal options of PCP treated wood. A treatment process has been developed in the laboratory scale to decontaminate PCP treated wood. In the first step of this process, the wood is chipped into small pieces. Then PCP is extracted using commercial grade ethanol. A three-step counter-current extraction under sonication removes more than 99% of the PCP from wood. In the next step, the remaining PCP is biodegraded utilizing a two stage bioreactor containing a white rot fungus. The PCP concentration in wood decreases to below detection limit (

Adsorption of pentachlorophenol by natural soils

Abstract The adsorption of pentachlorophenol, a listed hazardous substance, by natural soils was investigated at pH values of 4, 7, and 10 using various soils collected from the surface horizon. The effects of soil properties, such as organic carbon and fines content, were also studied and were found to have a significant positive correlation with the amount of solute adsorbed. Although soil properties strongly influence the process, the pH of the soil‐water system was found to be a primary factor which determines the affinity of solute for the soil particle surface. Pentachlorophenol, a weak organic acid, is transformed to pentachlorophenate ion at pH higher than pKa and adsorption is reduced. The anionic form of the molecule was found to be much more hydrophilic than the neutral form resulting in a two orders of magnitude reduction of the adsorption capacity as the pH was elevated from 4 to 10. The presence of cosolvents had a negative effect on the process leading to substantial reductions in the adsor...

Proposed Budget Cuts: Environmental Perspective

Those who have been involved in developing budgets at the enterprise level know very well that the process is driven by trade-off decisions. A trade-off is the reduction of resources from one initiative or program and the re-allocation of those resources to others. Trade-offs are motivated by the desire to fulfill the mission of the enterprise and to improve its outcomes. When the enterprise is the entire country, trade-offs should be viewed from the angle of the impact that those decisions will have on its citizens and society-at-large. The federal administration’s preliminary FY18 budget proposal contains unprecedented cuts in environmental programs across several agencies including EPA, DOE, NOAA, NASA, and USGS. The purpose of this commentary is not to debate the merits of the trade-offs between resources for environmentally related programs and other federally funded programs, but rather to outline its potential impacts to the public and society. In the words of Garrett Hardin [1], author of the Tragedy of the Commons, B...Ruin is the destination toward which all men rush, each pursuing his own best interest in a society that believes in the freedom of the commons. Freedom in a commons brings ruin to all....^ Society has entrusted the government with the protection of the commons and expects the government to bear that responsibility. One can think the environmental responsibility of the government in three dimensions: (a) restore the damage made to the commons by past practices intended or unintended; (b) maintain an adequate infrastructure of policies, regulations, oversight, and enforcement to protect human health and the environment; and (c) support science, analysis, and the creation of new knowledge to understand the impact of anthropogenic activities on the environment and take measures to protect future generations. To fully appreciate how the integration and harmonization of these three dimensions act to the benefit of humankind, one can read the 2015 update of BBeyond Discovery The Depletion of Earth’s Ozone Layer: Discovery and Response^ [2] published by the National Academy of Science. The administration’s proposed budget cuts are an assault across all dimensions mentioned in the paragraph above and across all of the agencies tasked with the responsibility of executing elements of, and programs within, those three dimensions. Although as it was mentioned above the budget reductions cut across environmental programs in a variety of federal agencies, none is more profound than the proposed cuts to the EPA budget which amounts to 31% of the total FY16 budget. Since the mid 1980s, the EPA budget has ranged between eight and ten billion inflation-adjusted dollars (about 0.2% of the total US federal budget). The proposed cuts will bring the budget down to 5.6 billion from 8.2 billion in FY16. This will be the lowest budget since the formation of the Agency in 1970. According to the EPA, 52% of the budget is used for clean and safe water, 23% for land restoration and preservation, 12% for clean air, 7% for healthy communities and ecosystems, and 6% for compliance and environmental stewardship. In FY16, EPA spent 22% of its budget on payroll for its 15,376 employees. Some estimate that the proposed budget cut will result in the termination of more than 3500 EPA employees. This will have a direct and immediate impact on the agency and its ability to deliver services. The proposed budget cuts impacting environmental programs and initiatives are numerous. Here is a sampler: * George P. Korfiatis gkorfiat@stevens.edu