Arthur D. Kney

Removal of Perchlorate from Contaminated Water Using a Regenerable Polymeric Ligand Exchanger

Abstract A polymeric ligand exchanger (PLE), DOW 3 N‐Cu, has been investigated for perchlorate (ClO4 −) removal from contaminated water. Batch kinetic tests revealed that the perchlorate sorption equilibrium for DOW 3 N‐Cu can be reached within 20 hours and perchlorate removal by DOW 3 N‐Cu follows standard ion exchange stoichiometry. Fixed‐bed column runs showed that 12,388 bed volumes of perchlorate‐free water can be obtained when DOW 3 N‐Cu was used to treat a simulated contaminated water with an influent perchlorate concentration of 200 µg/L. It was found that the regeneration of spent DOW 3 N‐Cu is pH dependent. It was shown that addition of ethanol and a surfactant Tween 80 to a 4% NaCl/2% NaOH regenerant solution increased the regeneration efficiency of spent DOW 3 N‐Cu by 11 and 5 percent, respectively. Nearly 90% of perchlorate capacity of saturated DOW 3 N‐Cu was recovered using 35 bed volumes of a regenerant containing 4% (w/w) NaCl, 2% NaOH, 5% Tween 80, and 5% ethanol.

Using electronic conductivity and hardness data for rapid assessment of stream water quality

A graphical screening method was previously developed by Kney and Brandes (2007) for assessing stream water quality data using electronic conductivity (EC) and alkalinity data. The method was aimed at providing citizen scientists involved in stream monitoring programs with a relatively simple way to interpret EC data. The method utilizes a plot of EC against concurrent alkalinity data, and is used to distinguish EC values for impacted or degraded streams from those that can be considered background values in a particular geologic setting. The method performs well in areas underlain by carbonate bedrock, as streams in those areas characteristically have EC values that are strongly correlated with alkalinity. However, in areas of low stream alkalinity (less than approximately 50 mg/L as CaCO(3)), the Kney and Brandes (2007) method was found to be much less effective in identifying impacted streams. This paper extends the graphical screening approach to streams with low alkalinity, specifically regions underlain by clastic sedimentary or crystalline bedrock, by using the strong correlation between EC and total hardness (TH). A baseline relationship of EC vs. TH is developed using surface water chemistry data from Hydrologic Benchmark Network streams (deemed as having minimal anthropogenic impacts) and regional groundwater quality data. The usefulness of the method is demonstrated by application to publicly available stream chemistry data and to field data collected from streams of eastern Pennsylvania under baseflow conditions. Results demonstrate that for streams with alkalinity <75 mg/L as CaCO(3), the TH-based graphical screening method should be used rather than the alkalinity-based method of Kney and Brandes (2007).

A Pilot Study on Phosphate and Nitrate Removal from Secondary Wastewater Effluent using a Selective Ion Exchange Process

A pilot study was conducted at a wastewater treatment plant (WWTP) in Easton, Pennsylvania, for the removal of varying concentrations of phosphate (HPO4 2-) and nitrate NO3 - using a newly developed ion exchange material referred to as Polymeric Ligand Exchanger (PLE). The PLE was prepared by immobilizing copper (II) ions onto a commercially available chelating resin, DOW-3N. The loaded copper ions act as ligand exchanger sites that selectively bind with target ligands such as phosphate and nitrate. This pilot study was the final experimental testing phase of the PLE toward the full process development for the selective removal of both phosphate and nitrate using secondary effluent from a fully operational WWTP. In order to establish the effectiveness of the PLE, a commercially available activated alumina (AA) was also tested for comparison. Effluent phosphorus and nitrate concentration of less than 0.1 mg l-1 were achieved for up to 500 bed volumes; phosphorous was reduced from an average concentration of 4.0 mg l-1 and nitrate from average concentration of 16.4 mg l-1. In accord with prior laboratory observations, the pilot test results showed that the PLE could selectively remove phosphate from secondary municipal wastewater effluent under normal conditions (pH, ionic strength, dissolved organic carbon content). In addition, the pilot study provided new evidence that nitrate could be removed from secondary municipal wastewater effluent and concurrently with phosphate. The selective ion exchange process provides an alternative for concurrent removal of the eutrophic-enhancing nutrients, phosphate and nitrate.

A yeast estrogen screen without extraction provides fast, reliable measures of estrogenic activity

Yeast estrogen screen (YES) has been used since 1996 as a bioassay to quantify activity in wastewater. Here we present a modification of YES to measure estrogenic activity in water. This modification, called yeast estrogen screen no extraction (YESne), is faster and easier than the common method. The modified method can detect 17β-estradiol equivalent concentrations down to 1.1 ng/L. The median effective concentration value (EC50) is 1.2E-10. It detected average influent concentrations of 16.4 and 17.5 ng/L of 17β-estradiol equivalent at four Lehigh Valley, Pennsylvania, USA, wastewater treatment plants on September 18 and October 23, 2008, respectively, and average effluent concentrations of 5.1 and 8.1 ng/L of 17β-estradiol equivalent at the same plants on the two dates, respectively. Reduction in 17β-estradiol equivalent activity for the four wastewater treatment plants averaged 67.8 and 52.3%, respectively, for the September 18 and October 23 samples. The YESne is a simple, quick method for quantifying estrogenic activity that has been used successfully in nonmajor undergraduate classes and could be adapted by wastewater treatment plant laboratory technicians to measure influent and effluent estrogenicity on a regular basis. This practice will greatly increase our knowledge base of estrogenicity in wastewater before and after treatment.

Removal of Heavy Metals Using Pervious Concrete Material

Pervious concrete material has been used as an alternative to impervious concrete and other pavement materials to reduce water runoff. Pervious concrete allows water to percolate through and into the subsurface soil. Unlike other pavement systems, pervious concrete used for environmental purposes needs to not only satisfy strength and freeze-thaw requirements, but also needs to provide adequate permeability and be modified for optimal environmental benefits (i.e., reducing heavy metal and hydrocarbon concentrations). Studies have shown that passing water containing these different contaminants through pervious concrete material reduces the concentration of these contaminants. Although few, some studies have focused on the reduction of heavy metal concentrations via pervious concrete material subjected to long-term submersion in water due to bacterial growth. This study focuses on the fundamental understanding of the roles different materials constituting pervious concrete play in their interaction with heavy metals as well as the mechanisms of this interaction. A pervious concrete mixture that satisfies strength requirements generally consists of aggregate, sand, cement and admixtures. Using 24-hour batch tests with copper concentrations between 5 mg/l and 20mg/l, the interaction of materials that constitute a pervious concrete mixture as well as a pervious concrete cylindrical sample were tested. In addition to monitoring the concentration of copper for 24 hours, pH and conductivity were also measured for each of the materials and for the pervious concrete samples.

A Comparison of Metal-Loaded DOW3N Ion Exchangers for Removal of Perchlorate from Water

Abstract In this work, an alternative class of perchlorate selective ion exchangers (known as polymeric ligand exchangers, PLEs) were prepared by loading six transition metals (Cu(II), Co(II), Zn(II), Ni(II), Fe(II), and Fe(III)) onto a commercially available chelating resin Dowex M4195 (DOW3N). The resultant PLEs (DOW3N-Me, where Me = one of the metals) were tested with respect to their perchlorate selectivity, capacity, kinetics, and regeneration efficiency through a series of batch and column experiments. Within this group of PLEs, DOW3N-Cu(II) showed the highest perchlorate capacity; all four PLEs had similar perchlorate sorption kinetics; and DOW3N-Fe(III) demonstrated better regeneration potential.

Bioremediation of perchlorate contaminated groundwater

The effectiveness of Azospira sp. KJ bacteria in removing perchlorate from water samples has been investigated in both batch tests and an upward flow bioreactor. The bacteria successfully degraded perchlorate down to an undetectable level in both studies.

Meeting the Challenge: Developing a Senior Capstone Design Project into a Meaningful, Practical, and Enjoyable Experience

Development a senior capstone design project for any program can be a challenge. The challenge starts with meeting a goal of achieving the involvement of an entire class on one project that focuses on all aspects of the particular engineering program. Additionally, a capstone course must be meaningful, practical, and enjoyable for the students, as well as the instructor. Adding to the mix, prerequisites of prospective employers, accreditation requirements and expectations of a professor to lead such a course escalate the challenge. And finally, any capstone course should represent a gateway into the real-world and bring together concepts and principles taught in earlier courses; therefore, ideally, it must have as many real-world components possible, making the challenge somewhat daunting to any professor at any school. This paper focuses on addressing a set of defined goals and how the challenges of meeting the goals were achieved in developing a civil engineering senior capstone course at Lafayette College.

Improving environmental and water resources engineering education at Lafayette College using watershed-based field studies

Multidisciplinary environmental issues associated with land development and nonpoint source pollution are increasingly addressed on a watershed-integrated level. The so-called “watershed approach” recognizes the interconnected nature of all aspects of environmental quality, including land use and water resources, and the need for sustainable growth, and thus becomes an effective way of connecting the seemingly disparate aspects of environmental engineering for our students. This paper presents a case study of the introductory course in environmental engineering at Lafayette College that we have designed around a rapidly developing 200-km 2 watershed whose outlet is adjacent to campus. Throughout the course, students take part in a variety of field and laboratory activities designed to give a complete picture of the challenges facing the watershed and to show how civil engineers can contribute to future environmental quality of the watershed. The course attracts students minoring in environmental science as well as civil engineering majors. The success of the course has been indicated by increasing numbers of civil engineering majors specializing in environmental and water resources engineering, and increasing numbers of students conducting independent research projects focusing on the watershed.

Development of a graphical assessment method for interpreting stream conductivity data

A newly developed graphical assessment method addressing conductivity data evaluation normalized by concurrent alkalinity data is introduced in this paper. This simple method provides insight into the complexity of a conductivity measurement. It enables users such as volunteer stream monitors and professionals to differentiate geological influences from anthropogenic influences. Conductivity is a measurement done by most water quality novices and specialists throughout the United States and around the world. Although conductivity is easy to measure the resulting data is often difficult to interpret due to geologic and anthropogenic influences, both of which contribute significant impact making the specific source difficult to trace. Within Bushkill Creek watershed (Northampton County, Pennsylvania) the bedrock geology is predominantly carbonate and shale, which naturally weather calcium, magnesium and carbonate ions into solution thereby providing a source of naturally high conductivity. However, the watershed is also influenced by anthropogenic activity. Volunteer stream monitors commonly document measurements of conductivity up to 1000 ∝mho/cm and at times higher, in the lower Bushkill watershed. Due to these elevated values, volunteers often raise as the question: “Is the high conductivity due to the natural geologic setting and/or the influence of anthropogenic sources?” This question illustrates the difficulty of conductivity evaluation.