Su L.,State University of New York at Buffalo |
Khunjar W.O.,Hazen and Sawyer P.C. |
Aga D.S.,State University of New York at Buffalo
Rapid Communications in Mass Spectrometry | Year: 2014
RATIONALE Monitoring the concentrations of pharmaceuticals and personal care products (PPCPs) in wastewater is an integral step toward understanding the fate of these contaminants in wastewater treatment plants (WWTPs). This paper aims to develop a method that allows for the simultaneous analysis of multiple classes of PPCPs that can be used as tracers to assess the performance of WWTPs. METHODS Five PPCP tracers - carbamazepine (CBZ), 17α-ethinylestradiol (EE2), nonylphenol (NP), salicylic acid (SA), and trimethoprim (TMP) - were analyzed by liquid chromatography/triple quadrupole mass spectrometry (LC/MS/MS) using a highly basic mobile phase (pH 10.3). Conventionally, TMP (pKa 7.12) and CBZ (pKa 13.94) are analyzed in positive ion mode using an acidic mobile phase. However, the high pH mobile phase allowed the quantification of all the tracers by polarity switching, with TMP undergoing wrong-way-round (WWR) ionization. RESULTS The instrument limits of detection for the five tracers, without solid-phase extraction, were in the range of 1.3 to 5.9 ng/mL, except for NP, which was 238 ng/mL. The signal-to-noise (S/N) ratios for TMP and CBZ with the mobile phase at pH 10.3 were higher than the S/N ratios observed at pH 2.7 under positive electrospray ionization. The mechanism of WWR ionization for TMP was investigated, and we propose that a charge transfer from solvent clusters to TMP molecules due to electrolytic reactions at the surface of the droplet leads to WWR ionization in electrospray. CONCLUSIONS A method to simultaneously analyze five representative PPCP tracers with a wide range of pKa values using WWR ionization in LC/MS/MS with polarity switching was developed. The method was successfully used to monitor the selected PPCPs in samples from full-scale WWTPs to assess their biodegradation under various treatment conditions. Copyright © 2014 John Wiley & Sons, Ltd.
Su L.,State University of New York at Buffalo |
Aga D.,State University of New York at Buffalo |
Chandran K.,Columbia University |
Khunjar W.O.,Hazen and Sawyer P.C.
Journal of Hazardous Materials | Year: 2014
To predict TOrC fate in biological activated sludge systems, there is a need to accurately determine TOrC biodegradation kinetics in mixed microbial cultures. Short-term batch tests with salicylic acid, 17α-ethinylestradiol, nonylphenol, trimethoprim and carbamazepine were conducted with lab-scale activated sludge cultures in which the initial TOrC concentration (1 mg/L and 0.0005 mg/L) and readily biodegradable substrate concentrations were varied. The results indicate that pseudo-first order kinetic estimates of TOrC are not sensitive (p > 0.05) to the initial TOrC concentration as long as the initial TOrC concentration (S0) to biomass (X0) ratio (on COD basis) is below 2 × 10-3. The presence of readily biodegradable organic matter suppresses TOrC biotransformation rates under nitrifying and denitrifying conditions, and this impact can be adequately described using a reversible non-competitive inhibition equation. These results demonstrate the importance of closely mimicking parent reactor conditions in batch testing because biotransformation parameters are impacted by in-situ carbon loading and redox conditions. © 2014 Elsevier B.V. All rights reserved.
Roberts M.,Hazen and Sawyer P.C. |
Cruickshank J.,Hazen and Sawyer
American Water Works Association Annual Conference and Exposition 2010, ACE 2010, Papers | Year: 2010
Challenging water quality situation Nitrification High DBPs High water age Challenging water supply situation WTP capacity approaching max Purchased supplies use different disinfectants MIEX treatment with distribution system split for separate disinfectants Hydraulic model helped to: Examine hydraulic and water quality effects of solution Propose improvements Comply with regulations Proactive approach to comply with Stage 2 and protect public health.
Alonso M.P.,Hazen and Sawyer P.C. |
Carney P.A.,Hazen and Sawyer P.C. |
Aguiar L.,071 SW 38th Avenue |
Fernandez-Cuervo V.,071 SW 38th Avenue |
And 4 more authors.
Pipelines 2014: From Underground to the Forefront of Innovation and Sustainability - Proceedings of the Pipelines 2014 Conference | Year: 2014
This paper describes two horizontal directionally drilled water main crossings beneath the Biscayne Bay to support the $31 million emergency replacement of the access bridges to Key Biscayne. The Miami-Dade Water and Sewer Department (MDWASD) replaced two sections of the existing 12-in. (300 mm) ductile iron water main between the City of Miami and the Village of Key Biscayne with 16-in. (400 mm) inner diameter high-density polyethylene (HDPE) pipe via horizontal directional drilling (HDD). HDD technology enabled the installation of the pipelines to be completed within the tight 10-month project schedule, minimizing environmental impacts and project costs. The installations were completed as part of the design-build replacement of the Bear Cut and West Bridge superstructures by Kiewit Infrastructure South Co. The existing water main was supported on the superstructure of the bridges, which forced its fast-tracked replacement. This is one of the most critical projects being completed in Miami-Dade County and will provide a new water main and improved access to more than 10,000 residents in Key Biscayne. © 2014 American Society of Civil Engineers.
Long T.L.,Hazen and Sawyer |
Luck A.,Hazen and Sawyer P.C. |
Barrett K.,Hazen and Sawyer P.C.
AMTA/AWWA Membrane Technology Conference and Exposition 2013 | Year: 2013
Four membrane manufacturers (GE Water, Norit, Pall and Siemens) provided installation lists of microfiltarion (MF) and ultrafiltration (UF) membrane projects where systems were installed in existing water treatment facilities across the United States and several installations in Canada. The owners and operators were surveyed and asked to comment on what was their driver was for installing membranes, what their major issues were with the project including plant start-up, operator training, and operations and maintenance challenges. In addition, they were asked what they would have done differently now that their plant has been in service for a while, and what they wished they had learned from other plants in advance. While the first part of the presentation will focus on the owner's drivers for selecting membranes and design considerations specific to membrane treatment process, the majority of the presentation will focus on the experiences of the operators themselves. It will present the challenges operators have experienced with integrating a membrane treatment process into a conventional treatment plant, performing commissioning and acceptance testing activities, training staff on a complex fully automated system with an entirely new set of terminology, control strategies, alarms, and difficulties they faced with operating and maintaining a membrane system. Most importantly it will give attendees the opportunity to learn from the experiences of other operators so they can be better prepared when they choose to integrate a membrane process into an existing treatment or new membrane treatment facility. © 2013 American Water Works Association.