Dawson T.A.,NTH Consultants, Ltd. |
Butler R.P.,NTH Consultants, Ltd. |
Edberg J.R.,NTH Consultants, Ltd. |
Gualandri T.,Greeley and Hansen Inc.
ITA-AITES World Tunnel Congress 2016, WTC 2016 | Year: 2016
In the early 1920's, the City of Tulsa, Oklahoma constructed an approximately 8,238-foot long tunnel, the Tiawah Tunnel, through bedrock. Voids behind the concrete tunnel liner were detected via probe drilling in early 2000 as part of an interior visual condition assessment. In 2012 and 2015, conditions along the entire tunnel were efficiently assessed through geophysical investigation using ground penetrating radar (GPR) along the inner tunnel crown and at various select locations within the tunnel. Fifty-seven (57) potential voids, extending up to 19 inches in depth and 12 feet in width, were detected with 1,000 MHz GPR and confirmed through probe drilling with approximately 80% accuracy. GPR proved to be an efficient and reliable technology for void detection behind concrete tunnel lining. This paper highlights the geophysical investigation and how geophysical efforts were combined with other investigation efforts to definitively determine the presence of voids outside of the tunnel lining.
Nelson D.,Greeley and Hansen Inc.
Journal - American Water Works Association | Year: 2014
The Envision™ sustainable infrastructure rating system provides planning and design guidance, performance evaluation, and award recognition to infrastructure projects that contribute to a sustainable future. As a rating system, Envision joins the ranks of LEED, Green Globes, SITES, and hundreds of other regional sustainable metric systems. Envision is currently available for use during planning and design phases. Within each phase, sustainability objectives are summarized in 60 credits organized in five categories, quality of life, leadership, resource allocation, natural world, and climate and risk. The Envision system offers three tools for project assessments, Envision checklist, Envision rating system, and Envision verification and award. ISI offers training and accredition for using the Envision tools the Envision rating system and mandatory for verification and award.
De Reamer G.,Greeley and Hansen Inc. |
Kassouf P.,Triad Engineering and Contracting Inc. |
Talley B.,City of Lafayette |
Dobbels D.,Jacobs Associates
Proceedings - Rapid Excavation and Tunneling Conference | Year: 2011
The City of Lafayette, Indiana, is located on the Wabash River in the central portion of the state. It is relatively small compared to most typical cities that incorporate tunnels into their combined sewer overflow (CSO) control solutions. This small size means less CSO flow resulting in an approximately 3-m-diameter (10-ft), 610-m-long (2,000-ft) tunnel, which is relatively short and has a relatively small diameter compared to many CSO tunnels. Nevertheless, the project was a large one from the owner's perspective. The urban setting and relative size and length of the tunnel, combined with highly variable ground conditions and shallow cover, resulted in several planning and design challenges and led to some novel applications of tried and true tunneling methods by the contractor, including use of compressed air and a built-up steel segment liner. One of the keys to the project's success was the teamwork and collaboration among the owner, the designer, and the contractor through the various stages of the project. This paper describes the planning, design, and construction of this successful project along with several lessons learned along the way from the designer's, contractor's and owner's perspectives.
Park C.,University of Massachusetts Amherst |
Fang Y.,Greeley and Hansen Inc. |
Murthy S.N.,DC Water and Sewer Authority |
Novak J.T.,Virginia Polytechnic Institute and State University
Water Research | Year: 2010
The effects of floc aluminum (Al) on activated sludge performance and 17-α-ethinylestradiol (EE2) removal were studied using bench-scale activated sludge systems. The results showed that higher Al-fed activated sludge led to better settling, dewatering, and effluent quality with better EE2 removal. EE2 concentrations in the effluent revealed correlations with effluent suspended solids and large particulate/colloidal effluent biopolymer (protein + polysaccharide). Furthermore, a significant correlation existed between effluent proteins and EE2 for all size fractions, indicating that hydrophobic proteinaceous colloids provide binding sites for EE2 and washout together into the effluent. These results suggest that aluminum plays a crucial role in bioflocculation of activated sludge and the efficacy of flocculation influences the removal of endocrine disrupting compounds (EDCs) from wastewater treatment systems. © 2009 Elsevier Ltd. All rights reserved.
Knocke W.R.,Virginia State University |
Zuravnsky L.,Greeley and Hansen Inc. |
Little J.C.,Virginia Polytechnic Institute and State University |
Tobiason J.E.,University of Massachusetts Amherst
Journal / American Water Works Association | Year: 2010
Many water utilities historically have produced highly effective manganese (Mn) removal by maintaining an active manganese dioxide (MnOx(S)) surface on their filter media that adsorbs soluble Mn. This process requires the presence of free chlorine to regenerate the media or the system fails, and some utilities have ceased adding free chlorine before their filters to pursue treatment goals such as disinfection by-product control or biological filtration. Often the result is elevated Mn levels in the finished water and a corresponding increase in consumer complaints. This research demonstrated the use of MnOx(S)-coated media as a postfiltration adsorptive contactor to provide cost-effective, efficient soluble Mn removal across a range of hydraulic loading rates, solution pH, influent Mn levels, and hypochlorous acid concentrations. Integration of the technology into treatment plants-via either new design or retrofit-could provide effective Mn control, especially at facilities seeking to eliminate free chlorine application to dualmedia filters and/or establish biofiltration across the filters.