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Sarasota, FL, United States

Carollo Engineers is an environmental engineering firm specializingin the planning, design, and construction management of water and wastewaterfacilities for municipal and public sector clients in the United States. The firm is headquartered in Walnut Creek, California, and currently maintains 38 offices throughout the United States. Carollo has provided services to the City of Phoenix for over 80 years and to Southern California's Orange County Sanitation District for over 50 years.Carollo Engineers employs civil, structural, electrical, mechanical, environmental, and instrumentation and control engineers, as well as scientists, planners, architects, and CAD designers. Carollo offers water supply, treatment, and distribution engineering services; watershed and water resources planning; storm water and urban wet weather planning, permitting, and regulatory assistance; computer modeling, master planning, decision support analysis, and financial assistance services; and reuse studies. Carollo is also involved in planning and design of biogas cogeneration and standby power facilities for the water and wastewater industry; provides utility finance, business planning, asset management, infrastructure engineering, and water reclamation/reuse services; and provides program/construction management services for public work facilities and industrial and private structures.The company’s projects include pilot and treatment studies, pump stations, pipelines, solids handling facilities, and reservoirs. It serves public agencies, private developers, and industrial firms. Carollo has offices in Los Angeles, San Francisco, San Diego, Pasadena, Sacramento, Walnut Creek, Fresno, Bakersfield, Fountain Valley, and Riverside, California; Las Vegas and Reno, Nevada; Phoenix and Yuma, Arizona; Portland, Oregon; Seattle, Washington; Boise, Idaho; Salt Lake City, Utah; Broomfield and Littleton, Colorado; Kansas City, Missouri; Chicago, Illinois; Oklahoma City, Oklahoma; Charlotte, North Carolina; Dallas, Houston, Fort Worth, and Austin, Texas; Boston, Massachusetts; and Miami, Tampa, Orlando, Sarasota, Palm Beach, and Hollywood, Florida.Carollo Engineers is a Regional Sponsor for Water For People, which helps developing countries improve their quality of life by supporting the development of locally sustainable drinking water resources, sanitation facilities, and health and hygiene education programs. Wikipedia.

Gould G.,Carollo Engineers
Proceedings - Rapid Excavation and Tunneling Conference

Project No. 669 of the Paradise Whitney Interceptor Project for the Clark County Water Reclamation District includes construction of a new sanitary sewer interceptor utilizing trenchless methods for eight reaches totaling 13,481 linear ft and open cut methods for 13,483 linear ft. The gravity sewer ranges in inside diameter from 60- to 84-in., some with 76-in. steel casing. The project presented numerous design challenges including complicated geology, close proximity to existing underground utilities, limited surface access, and other factors forcing trenchless drive lengths up to 1,500 ft. The tunnels will be constructed utilizing trenchless methods that include earth pressure balance machines and microtunnel machines; ground improvement is required on many of the drives. Construction of this project began in late 2014 and is expected to take over two years to complete with a total construction budget of $62.3M. Source

Rossell R.P.,Carollo Engineers | Ting F.C.K.,South Dakota State University
Journal of Hydraulic Engineering

The two-dimensional (2D) depth-averaged river model Finite-Element Surface-Water Modeling System (FESWMS) was used to simulate the hydraulic conditions at a contracted bridge site. The site studied was the James River bridges near Mitchell, South Dakota. The parallel bridges are located in a crossing between the two bends of a meander. The floodplain alignment relative to the channel and skewed bridges produces complex 2D flow patterns that cannot be predicted accurately by using a one-dimensional (1D) river model. The 2D model was validated by using flow measurements collected by the USGS during three high-flow events with return periods ranging from 25 to 100 years. The validated model was used to examine the site characteristics that influence the concentrated flow on the right side of the main channel and the exchange of flow between the main channel and floodplains. The rating curves derived from the 2D model and the results of soil erosion tests were used to evaluate live-bed and clear-water contraction scour at the bridge site. The scour analysis was conducted by using the equations in Hydraulic Engineering Circular No. 18 (HEC-18) and a method that accounts for the soil erodibility by using a curve of measured erosion rate versus shear stress. The study found that channel meandering, the no-flow boundary condition imposed by the walls of the river valley and skewed roadway embankment, and the dense trees along the left bank are the three main factors that create the unique hydraulic conditions at the bridge site. It is shown that using a 2D flow model could improve the estimation of contraction scour by providing more accurate information on the hydraulic parameters. The predicted scour depth was very sensitive to the critical shear stress and slope of the curve of erosion rate versus shear stress. Therefore, design should incorporate uncertainty in soil properties. It is also shown that an unsteady-flow approach to scour would produce a more realistic curve of predicted scour depth versus time. However, the cumulative effects of multiple flood events must be evaluated if time-dependent scour is used in design. © 2013 American Society of Civil Engineers. Source

Lampert D.J.,University of Texas at Austin | Sarchet W.V.,Carollo Engineers | Reible D.D.,University of Texas at Austin
Environmental Science and Technology

The effectiveness of thin-layer sand capping for contaminated sediment management (capping with a layer of thickness comparable to the depth of benthic interactions) is explored through experiments with laboratory-scale microcosms populated with the deposit-feeding oligochaete, Ilyodilus templetoni. Passive sampling of pore water concentrations in the microcosms using polydimethylsiloxane (PDMS)-coated fibers enabled quantification of high-resolution vertical concentration profiles that were used to infer contaminant migration rates and mechanisms. Observed concentration profiles were consistent with models that combine traditional contaminant transport processes (sorption-retarded diffusion) with bioturbation. Predictions of bioaccumulation based on contaminant pore water concentrations within the surface layer of the cap correlated well with observed bioaccumulation (correlation coefficient of 0.92). The results of this study show that thin-layer sand caps of contaminated sediments can be effective at reducing the bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) provided the thickness of the cap layer exceeds the depth of organism interaction with the sediments and the pore water concentrations within the biologically active zone remain low (e.g., when molecular diffusion controls transport from the underlying sediment layer). © 2011 American Chemical Society. Source

Upadhyaya G.,University of Michigan | Clancy T.M.,University of Michigan | Snyder K.V.,University of Michigan | Brown J.,Carollo Engineers | And 2 more authors.
Water Research

Contaminant removal from drinking water sources under reducing conditions conducive for the growth of denitrifying, arsenate reducing, and sulfate reducing microbesusing a fixed-bed bioreactor may require oxygen-free gas (e.g., N 2 gas) during backwashing. However, the use of air-assisted backwashing has practical advantages, including simpler operation, improved safety, and lower cost. A study was conducted to evaluate whether replacing N 2 gas with air during backwashing would impact performance in a nitrate and arsenic removing anaerobic bioreactor system that consisted of two biologically active carbon reactors in series. Gas-assisted backwashing, comprised of 2min of gas injection to fluidize the bed and dislodge biomass and solid phase products, was performed in the first reactor (reactor A) every two days. The second reactor (reactor B) was subjected to N 2 gas-assisted backwashing every 3-4 months.Complete removal of 50mg/L NO 3 - was achieved in reactor A before and after the switch from N 2-assisted backwashing (NAB) to air-assisted backwashing (AAB).Substantial sulfate removal was achieved with both backwashing strategies. Prolonged practice of AAB (more than two months), however,diminished sulfate reduction in reactor B somewhat. Arsenic removal in reactor A was impacted slightly by long-term use of AAB, but arsenic removals achieved by the entire system during NAB and AAB periods were not significantly different (p>0.05) and arsenic concentrations were reduced from approximately 200μg/L to below 20μg/L. These results indicate that AAB can be implemented in anaerobic nitrate and arsenic removal systems. © 2011 Elsevier Ltd. Source

University of Michigan and Carollo Engineers | Date: 2010-07-21

A system and method for simultaneous biologically mediated removal of contaminants (including at least arsenic or nitrate) from water are disclosed herein. The system includes i) a bioreactor having a length suitable for housing at least three different microbial populations, or ii) two bioreactors coupled together, the two bioreactors each having a length and an empty bed contact time that together are suitable for housing at least three different microbial populations. The system also includes a biofilm attachment medium positioned in i) the bioreactor, or ii) the two bioreactors; and the at least three different microbial populations formed on the biofilm attachment medium. The microbial populations are selected from oxygen reducing microbes, nitrate reducing microbes, arsenate reducing microbes, sulfate reducing microbes, and uranium reducing microbes.

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