Solve your environmental challenges: 1-415-381-5195

Books co-authored and co-edited  by James A. Jacobs

James Jacobs and Roger Brewer
The fragmented approach for remediation planning often involves sequential remediation in different treatment zones rather than long-term planning using a comprehensive simultaneous remediation design in order to obtain site closure. One way to handle the simultaneous remediation approach is using Environmental Hazard Evaluation (EHE). EHE includes the subsurface investigation phase and is based on the use of pre-approved, comprehensive, Environmental Screening Levels (ESLs, referred to as action levels or EALs in some states). The site investigation is designed to identify the presence or absence of each hazard on the basis of applicable ESLs, not simply define the vertical and lateral extent and magnitude of soil and groundwater contamination. This comprehensive approach helps avoid the need for time-consuming and costly remobilization for additional sampling in the future. In addition, it addresses the common concern from regulators that although the lithologic and chemical data have been collected, the site closure request has not been justified.

The results of the EHE are used to prepare site Environmental Hazard maps that depict areas where soil and groundwater contamination pose specific environmental hazards. This is carried out by comparing soil, groundwater, and, in some cases, soil gas data to detailed ESLs for specific environmental hazards. Maps that collectively summarize areas of the site where specific environmental hazards are present are then prepared (i.e., based on a review of all contaminants of concern) and site conceptual models are prepared as well as potential exposure pathways. The hazard maps are then used with the results of the site investigation to divide contaminated areas into three Remediation Management Zones: Zone 1 (source zone: aggressive treatment to remove priority environmental hazards), Zone 2 (residual zone: passive treatment to address intermediate priority hazards), and Zone 3 (attenuation zone: monitoring to ensure contamination is not spreading). Specific environmental hazards associated with each zone are clearly identified from the start of the project (direct exposure, vapor intrusion, leaching, etc.). The zone boundaries are either ESLs applicable to the targeted hazards or the treatment limits of particular remedial technologies. A San Francisco, California site will be examined where Remediation Management Zones were used in the planning and design phase of the project. Ozone was used in Zone 1 and enhanced bioremediation using oxygen infusion was used in Zone 2. The current status of this project will be discussed.

Presenter: James A. Jacobs, P.G., C.H.G., Environmental Bio-Systems, Inc., 707 View Point Road, Mill Valley, CA 94941; Telephone: 415-381-5195;

Roger Brewer, Ph.D., Hawai’i Department of Health, Hazard Evaluation and Emergency Response, 919 Ala Moana Boulevard, Honolulu, HI 96816, Telephone: 808-586-4328;

James A. Jacobs
Platform Presentation

A three-step flushing, extraction and infusion process has been developed for removal of free product (hydrocarbons and chlorinated solvents). Flushing was performed at a former tank pit at a northern California site containing heavy oil-range hydrocarbons that were trapped beneath the saturated zone. Flushing uses a two-step flushing process which includes high-pressure air injection and biosolvent injection to thin and mobilize diesel-range or heavier hydrocarbons, which was measured up to 41 cm in height in one well on one site. The high-pressure air injection and biosolvents were used with dual phase extraction to recover both the heavy oil and the biosolvent.

At another site, biosolvent flushing was performed followed by a Supersaturated Water Injection (SWI) technology with carbon dioxide saturated water injection. SWI allowed for controlled mobilization of petroleum hydrocarbons into the water table for collection using dual phase extraction. SWI technology relies on water which is supersaturated with carbon dioxide using a mass transfer system. The saturated water is injected under high pressure into the former tank pit where carbon dioxide bubbles nucleate at the targeted area of the aquifer. The rising carbon dioxide bubbles contact with the submerged diesel-range hydrocarbons in the saturated zone and cause volatilization of the free product into the vapor phase and mobilization of NAPL trapped in the pores.

Several extraction wells and dozens of small-diameter reinjection ports were used to recirculate the carbon dioxide saturated water and provide a closely-spaced delivery and extraction system. The carbon dioxide is distributed by flowing water resulting in effective carbon dioxide distribution followed by heterogeneous bubble nucleation and continuous growth of gas bubbles in situ. A gas saturation front developed which expanded laterally and vertically towards the water table in the former underground tank pit. Diesel-range hydrocarbons mobilize to soil gas and are extracted with a dual phase extraction system. Case studies will be described. After the carbon dioxide SWI process, a similar SWI process using oxygen is used to flood the saturated remediation area with oxygen for enhanced bioremediation.

James Jacobs, P.G., C.H.G.
Environmental Bio-Systems, Inc.
707 View Point Road, Mill Valley, CA 94491; Tel: 415-381-5195;;

James A. Jacobs and Jon Elam
A green business model was developed for the Tamalpais Community Services District (TCSD), located in unincorporated Mill Valley, California. The agency performs solid waste, sewer collection and Park and Recreation services for 2,550 households. With an annual budget of $4.3 million (2008-9), TCSD focuses on managing resources and protecting groundwater and surface water, while also collecting waste. In the process of providing collection services, savings related to energy use and landfill diversion were noted. In 5 years, landfill garbage has been reduced 20% and recycling and green waste (turned into mulch) has increased by 33%. TCSD recycled more than 1,304 tons of paper, cardboard and plastics.

TCSD will collect 100 lbs of used and outdated medicines in 2009. In prior years these pharmaceutical wastes were likely dropped into toilets and released into surface waters after standard wastewater treatment or placed in the refuse containers and deposited in the landfill where the these unregulated chemicals could leach into groundwater. Other recycling programs have diverted 3 tons of electronic wastes (TVs, microwaves, computers) per year from landfills. In 2008, battery drop-off collection saved about 1,000 lbs heavy metals, mostly lead and cadmium as well as battery from leaching into the landfill groundwater. Over12 months, 600 compact fluorescent light bulbs (CFLs) and 480 fluorescent lamps containing 3.0 Kg and 5.8 Kg of mercury, respectively, will be recycled and diverted from the landfill. Between 2005 and 2008, garbage collection was reduced from 2,300 to 1,900 tons, a savings of 800,000 lbs of waste not filling local landfills.

The Mill Valley area served by TCSD lies at sea level on Richardson Bay a part of the greater San Francisco Bay. Due to two tidally influenced creeks, groundwater within about 1 mile of the shoreline is usually encountered within 3 feet of ground surface. Most of the flatland in the valley was originally bay marsh, and significant subsidence occurred over the past 50 years on the residential structures, roads as well as the sewer laterals and main pipelines, causing significant wet weather inflow and infiltration. TCSD has reduced wet weather flows to it’s two nearby wastewater treatment plants by 10% by reducing infiltration and inflow and by repairing numerous broken sewer laterals and mains. One set of sewer repairs has reduced wet weather flow to one wastewater plant by 40%. With less pumping of storm water and shallow groundwater, energy consumption was reduced by 20% in 2008 from 2006. The focus on environmental sustainability has lead to a waste collections program which saves money, environmental resources and generates broad community support.

Authors: James A. Jacobs, PG, CHG, is a board member of TCSD and Chief Hydrogeologist with Environmental Bio-Systems, Inc., 707 View Point Road, Mill Valley, CA 94491; Tel: 415-381-5195;,

Jon Elam is General Manager of TCSD, 305 Bell Lane, Mill Valley, CA 94941; Tel: 415-388-6393;