JHA was contracted by CB&I Federal Services LLC (now APTIM) to provide In-Situ Bioremediation injections at the Alameda Point IR OU-2B site in Alameda, California (Site). The first event (phase) of the project was recently conducted in April – May 2018. JHA performed the Enhanced Bioaugmentation at this Site utilizing lactose and an emulsified vegetable oil (EVO) carbon amendment, to treat chlorinated solvent-impacted groundwater. The injections were delivered into 386, 2” diameter injection wells at varying depths of 20 feet to 40 feet below ground surface (bgs) in both the diffuse plume and hot-spot areas. A total of four injection events are proposed in the hot spot and diffuse plume over a four year span.
JHA was responsible for creating the anoxic water prior to injections with the use of Sodium Sulfite. Hydrant water supply, water meter, back flow preventer, hoses and bulk water storage tank(s) were all utilized. Mobilization/Demobilization included all labor and material necessary to mobilize equipment to the site, prepare for site work, site clean-up, and demobilization of materials and equipment for each event. JHA amended the stored hydrant water with sodium ascorbate to pre- condition the water in order to obtain a dissolved oxygen concentration at or below approximately 0.5 milligrams per liter. To avoid damaging the formation with prolonged pressurized injections and to prevent daylighting, introduction of the reagent solution was conducted at no greater than a maximum injection pressure of 10 psi. JHA injected the solution into 10 to 15 wellheads simultaneously via a manifold and hose system.
JHA injection equipment included providing all basic tanks, hoses, and connections for the wells. JHA provided two trailers with approximately 1,000 to 1,300 gallon mixing tanks, injection/recirculation pumps, generators, low flow dosimatic pumps and multi point injection manifolds that allowed connection to 10 to 15 wells simultaneously. JHA’s manifold system included appropriate valves and flowmeters for the tracking of volumes, and flow rates required to control the injection process. JHA also had customized wellhead assemblies that included a local shutoff valve, local pressure gauge, and an air release valve to prevent air entrainment in the formation and prevent in-well air lock during the injection for each injection well. The trailers were mobilized throughout the injection areas to complete the injections. Each JHA trailer was equipped with portable spill containment berms large enough to contain the trailer, tank, and all of its components. JHA provided forklift and operators to manage the shipment and movement of substrates throughout the site.
Daylighting was a serious concern at this site due to the shallow groundwater. JHA managed the daylighting through sequencing and optimizing the well field. Our understanding of the formations reaction to our injections received high accolades from our client. JHA injected a total of 268,000 gallons into 386 wells.