Johnston Construction Co.

Owner:

Howard County, Maryland

General Contractor:

Johnston Construction Company

Scope Of Work

Johnston Construction Company, as construction manager and general contractor with Post, Buckley, Shuh & Jernigan, Inc. as the engineer of record, provided engineering, demolition, site work construction, general construction, and project commissioning services under a guaranteed maximum, CM at Risk contract for the phased construction of the $10,135,000 project. This project followed a pre-construction services contract where Johnston Construction Company and Post, Buckley, Shuh & Jernigan, Inc. collaborated to develop the conceptual design concepts into a 90% design package that subsequently served as the bases for the guaranteed maximum price for the two-phase demolition and construction project.

Improvements to the Little Patuxent Water Reclamation Plant (LPWRP) were necessary due to the expansion of the Dreyer’s Grand Ice Cream facility located in Savage, MD into the largest ice cream producer in North America in 2006 and 2007. The ice cream production facility is part of Dreyer’s Grand Ice Cream, Inc., a subsidiary of Dreyer’s Grand Ice Cream Holdings, Inc. that is a wholly-owned subsidiary of Nestle S.A. The improvements at the LPWRP were required to treat nutrients received from the Dreyer’s ice cream plant that overloaded the treatment process particularly during the winter season. The CM at Risk delivery method facilitated an accelerated schedule with design starting in early 2006; equipment and material deliveries for construction starting in the spring of 2007; and, start-up and commissioning of the plant completing by the end of January 2008.

The improvements included site preparation with associated demolition work and construction of several major facilities with mechanical and electrical equipment. Site preparation and demolition included: general site excavation; the demolition of a truck scale; removal of two 4,000 gallon underground storage tanks for diesel and gasoline; concrete demolition of walls, curbing, and pre-cast tanks; mechanical demolition of clarifiers and aeration tanks; the refurbishment of two 250 HP Hoffman centrifugal blowers; the relocation of concrete reinforced electrical duct banks containing 15KV main power feeders and fiber optic network cabling, electrical manholes; and, repairs to address leakage at the expansion joints and flood gate valves in the existing aerobic reactors. Construction of new facilities included: a concrete tank to house the new Siemens Water Technology - Envirex dissolved air flotation separator with pressurization system equipment; a new Biorem odor control system with biofilter; the installation of two Envirodyne clarifiers in the existing concrete tanks; a new Sanitaire diffused aeration system with stainless steel air piping; the installation of a new FRP baffle system in the Aerobic Reactor tank to control flow; pump installation with six Vogelsang rotary lobe pumps, four Flowserve centrifugal pumps, one Penn Valley double disc pump, two Flygt submersible propeller pumps, one Vaughan submersible chopper pump, and two existing Borger rotary lobe pumps; retrofitting existing buildings for new equipment; interior piping renovations; and, site restoration.

Johnston Construction Company performed several construction techniques that provided time and cost savings for the client. The reuse of existing valves and stainless steel piping that was in good condition plus utilizing galvanized in lieu of stainless steel columns in the Aerobic Reactor resulted in capital cost savings of about $50,000. Proactive testing of existing underground pipelines discovered a significant leak in a 10-inch pipeline that was repaired. Interior pipe designs were modified to provide the best layout, to avoid interference with other facilities, and to minimize head loss and installation time. Calculations were performed for tank shoring requirements to maintain operation during new tank construction.

Johnston Construction Company performed the excavation, backfill, demolition, mechanical, piping, finish grading, concrete foundation, sidewalks, pads, and associated works for the two anaerobic digesters and a flare provided by ADI Systems under a separate design-build contract with Howard County. The value of this work performed by Johnston Construction Company was $1,400,000. It was completed in November 2007.

The CM at risk schedule for improvements at the Little Patuxent Water Reclamation Plant to receive wastewater flows from the Dreyer’s ice cream plant started with design in early 2006 and construction completion in January of 2008.