CICEET Progress Report for the period 9/01/01 through 3/01/02

Project Title: Natural and Enhanced In Situ Bioremediation of Petroleum-Contaminated Salt Marshes: Technology Development
Principal Investigator(s): Nancy E. Kinner, Stephen H. Jones, David W. Fredriksson

Accomplishments
During the period covered by this progress report (August1 2001, through January 31, 2002), we had five goals: (1) conclude the field evaluation of the effectiveness of the bioremediation technologies, (2) analyze data from the 2001 season, (3) design hydraulic studies of injection mechanics, (4) continue work on a prototype injection system, and (5) submit this progress report. This period includes our fourth field season, which began on March 30, 2001 and continued until September 28, 2001(considered as October event).

Progress on Tasks

1. Field Sampling

   The first sampling event for the fourth field season (2001) occurred on March 30 and 31. Sampling is a two-day process because four randomly selected grids must be sampled within each plot due to high in situ and analytical variability of sediment total petroleum hydrocarbons (TPH). Sampling can only be conducted in a 3-4 hour window when the tide is low exposing the marsh sediments. Parameters measured include TPH, pH, salinity, plant density, plant height, abundance of oil-degrading microorganisms, nitrate, ammonia, sulfate, and phosphate. Porewater samples, in particular, must be obtained slowly (at low tide, porewater yields are low), requiring as much as 45 minutes each. To prevent trampling the marsh grass and compacting the sediments, portable catwalks must be moved onto the marsh and placed to allow access to each randomly selected grid sampled, some of which are not accessible from the sides of the plots. The sampling team typically consists of two graduate students and one to three undergraduates.

   Three sampling events occurred (one per month) during the period covered by this report. The 2001 season was the last sampling season of this grant. Weekly nitrate addition and continuous air injection began for the 2001 season the week of May 7 and concluded after the final sampling event. No nutrients additions were made since the last report. After the final sampling event the catwalks were removed from the site and brought to UNH for storage.

   Undergraduate students in mechanical engineering helped with the final sampling event and catwalk removal. These students are involved with the prototype injection system (discussed in Section 4). They volunteered to help with the sampling to obtain a better understanding of the sampling process and to see the heterogeneous topography of the marsh. Jennifer Hamblet and Justin Gove continued to work in the field and the laboratory for the 2001 sampling events. Jennifer has also been working throughout the school year, assisting with laboratory work and data analysis.

   Graduate student, Dalia Hildebrand, successfully defended her thesis on November 16, 2001 and graduated with her master's degree in December 2001. Graduate student, Melinda Bubier, has been continuing the field and laboratory work for the 2001 season. Melinda began her fieldwork in Fall 2000 and is currently working on data analysis and assisting in development of the prototype injection. She will also continue working on the hydraulic experiments.

2. Data Analysis from the 2002 Sampling Season

   Melinda and Jennifer are currently performing the data analysis on all 2001 events, as well as several of the last events from the 2000 season. The GC used to analyze the TPH extracts was not functioning properly in October 2000. Various problems persisted through the first of the 2001 season creating a backlog of samples. These samples were all run during November and December 2001 and the data is currently being compiled. Because samples are frozen, holding them for future analysis is not a problem. Most of the data is showing very low concentrations in all of the plots. Many of the samples are now below the detection limits of our process.

3. Hydraulic Studies of Injection Mechanisms

   One of the goals of this grant was to understand how best to conduct the injection (e.g., at high or low tide; pumped or by gravity). The first part of this study was detailed in the last progress report. No more studies have been done since that time. Further studies to test the hydraulics of injecting during high tide are scheduled for this spring. Tentative plans are to use one of the former study plots, possibly the air plot due to its easier accessibility.

4. Prototype Injection System

   In September, the conceptual design and preliminary component testing of a floating vehicle to perform nitrate injections autonomously (at high tide) was initiated and is currently being performed by two undergraduate mechanical engineering groups as part of the TECH 797 Ocean Projects course. It is planned that the two undergraduate teams will complete the preliminary design by the end of the academic year 2001-2002. Each of the project groups is responsible for the initial design of one of the two major components, the delivery vessel and the injection system.

   Delivery Vessel: The prototype delivery vessel is being designed for shallow water application to navigate through the salt marsh at high tide to predetermined locations. At these positions, the "on board" injection system will move vertically downward into the marsh sediments for the introduction of the amendments. The vessel is being designed with a shallow draft to operate at high water to minimize impact on the marsh grasses. The component prototype consists of a double pontoon design using closed-cell polyurethane foam with possibly a fiberglass resin coating. The propulsion system is being designed as a low speed, high torque paddle wheel arrangement that "crawls" through the marsh. Currently, gear motors with a 10:1 ratio and an output torque of 226 in-lbs are being investigated to drive the wheels, which are arranged to be able to move the vessel in multiple directions. A wireless control system is also being investigated in which the operator can remotely log onto a computer on the vessel for the purpose of programming waypoints and monitoring the vessel's position.

   Injection System: The injection system will be mounted on the shallow water delivery vessel to introduce the amendment into the marsh sediments. In this prototype design stage, it consists of 36 pneumatically driven syringes with stainless steel needles attached to a fiberglass grid (See Figure 1).

   Each syringe mechanism is fitted with a check valve arrangement that enables intake of the fluid into the barrel and subsequent injection through the stainless steel needle. The entire grid, syringe and needle assembly will be driven into the marsh sediment by its weight force and removed using a motor driven winch. To prevent breakage of the needles during insertion onto hard objects in the sediment, each syringe barrel is fitted with retraction springs sized to be slightly greater than the individual injection resistance (approximately 1 lbf). The control of the injection system will consist of a programmable logic controller (PLC) powered by a deep cycle marine battery. Relays, used in conjunction with the PLC, will supply the appropriate current to the winch motors and air/vacuum device for the pneumatic syringes. Ultimately, this control system will be integrated with the one controlling the propulsion of the vessel.

Difficulties Encountered
The main difficulty encountered has been due to the low concentrations of TPH in the test plots. These low concentrations are causing many of our samples to be below detection limits. However, these low concentrations also mean that the marsh is being remediated, which is very good.

Anticipated Success in Meeting Project Objectives in Scheduled Project Period
At this time, we do not foresee any problems meeting our project objectives by the end of the grant in Summer 2002.

Preliminary Results

Petroleum Biodegradation
TPH concentrations in all plots (including the controls) are now very low. These low concentrations are believed to have decreased the biodegradation rates due to mass transfer limitations. More significant conclusions may be reached when all the data analysis is complete.

Tasks and activities for next reporting period

Tasks for the next reporting period
During the period February 1 to July 31, 2002, we will finish data analysis on the four amendment plots. We will submit the final report for the first CICEET Salt Marsh Grant. We will conclude the hydraulic studies and prototype development. Testing and technology transfer of the prototype injection system will occur throughout Spring 2002. We will also participate in a CICEET sponsored Information Transfer Workshop on March 22.

Work plan to accomplish tasks
We will continue using analytical protocols we have used during the current reporting period, as outlined in the original proposal and the previous progress reports. We will conduct the hydraulic studies as outlined in the grant proposal. The two groups of students in Tech 797 will finish their work on the prototype and present it as part of their course requirements.

An Information Transfer Workshop will be held at UNH on March 22. The workshop will bring together CICEET PIs, NERRS educators and potential end users of CICEET-developed technologies. The goal of the workshop is to develop specific, innovative strategies for rapidly and effectively transferring CICEET-generated technologies to appropriate end users. The salt marsh bioremediation study has been selected as one of the projects for participation in the workshop.

Concerns or difficulties
At the present time, we have no concerns or difficulties that we think will prevent us from completing the project.

Expenditures
The project is within budget at this time. There have been no unusual expenditures