OBG PRESENTS: Environmental Engineering Groundwater Remediation Pilot-testing an Air Sparge System for Arsenic Removal: Vineland Chemical Superfund Site, Vineland, NJ July 17, 2018 Joint Luncheon of the Southern Nevada NSPE/ASCE Today’s Presenters
Nick DiMarcello Pilot System Construction/OM&M Task Manager Senior Project Manager
Bella Bakrania, E.I.T. Pilot Test Workplan and Report Task Manager Associate Engineer
2 AGENDA History of Arsenic/Lead Pesticide Use in NJ Vineland Chemical Site History and Setting Site Characterization Arsenic Geochemistry and Treatability Testing
Air Sparge Pilot Testing 3 Arsenic/Lead Pesticide Use in New Jersey
Common arsenical pesticides:
Lead hydrogen arsenate – PbHAsO4
Paris green (Copper acetoarsenite) – Around the turn of the 20th
Cu(C2H3O2)2·3Cu(AsO2)2 century, use became prominent in the United States especially London purple (Calcium arsenate) – for insect pest control. Ca3(AsO4)2
4 Arsenic/Lead Pesticide Use in New Jersey
By 1917, routine use of lead arsenate on apple and peach crops was recommended by the NJ Agricultural Experiment Station.
Typical application - several pounds per acre.
Phased out in mid-1960s in favor of synthetic organochlorine pesticides (DDT, dieldrin, etc.).
5 Arsenic/Lead Pesticide Use in New Jersey
Lead arsenate also used for agricultural pest control in:
Vegetable fields Golf courses
Other fruit orchards Turf farms
White potato fields commonly received applications of calcium arsenate
6 Arsenic/Lead Pesticide Use in New Jersey
From 1900 to 1980, about 49 million pounds of lead arsenate and 18 million pounds of calcium arsenate were applied to soils in New Jersey.
The largest amounts of arsenic were applied in Coastal Plain counties in the southern part of the State.
7 Arsenic/Lead Pesticide Use in New Jersey
Who were the manufacturers ? There were many – major/minor.
For example, a 1921 report by the NJ Agricultural Experiment Station lists evaluations of 211 brands by 47 different manufacturers.
8 Arsenic/Lead Pesticide Use in New Jersey (Estimated)
Vineland NJDEP SCC Chemical 20 mg/kg As Superfund Site
9 Arsenic/Lead Pesticide Use in New Jersey (Estimated)
Persistence of Arsenic in groundwater and streams
NJDEP GWQS 3 ug/L As
10 Arsenic/Lead Pesticide Use in New Jersey
Arsenicals tend to bind tightly to the soil – most often in the surface layer.
Persistent in the environment and thus may be present in the soil long after they have been applied.
Many of the manufacturing sites and usage areas are not “gone”— because the metal-based pesticides do not degrade—but are “hidden” until discovered by development.
11 Arsenic/Lead Pesticide Use in New Jersey
Health effects and common action limits:
ARSENIC (NJDEP Unrestricted Soil Cleanup Criteria = 20 parts per million or ppm). Long-term exposure can cause skin abnormalities, including the appearance of dark and light spots on the skin, which may ultimately progress to skin cancer. Arsenic has also been associated with an increased risk of liver, bladder, kidney and lung cancer.
LEAD (NJDEP Unrestricted Soil Cleanup Criteria = 400 ppm). Lead is of particular concern for infants and young children because it can affect their developing brain and nervous system. High levels of lead affect the nervous system and kidneys of adults and children.
12 Site History and Setting
Blackwater Branch
NJ Route 55
Maurice River
Union Lake and City of City of Millville Vineland over here
13 Site History and Setting Vineland Chemical Company operations
45-year history of arsenic-based pesticide manufacture
Approx. 1,100 tons of waste byproduct per year
Several manufacturing/storage buildings, several un-lined lagoons, and former chicken coops, on a 54-acre site
Prior to 1977, by-product arsenic salts stored in open piles and in the chicken coops
Some cleanup in 1982 (in response to State action) – production process modified (non-contact cooling water system), two lagoons lined, stormwater collection, waste salt piles disposed
Wastewater treatment system to remove arsenic (1982) – designed for 35,000 gallons/day; excess flow of contaminated water up to 150,000 gallons/day was directed to [unlined] percolation lagoons
14 Site History and Setting Hydrogeologic setting: NJ Coastal Plain/Cohansey aquifer
Cretaceous age, part of the Kirkwood-Cohansey regional water-table aquifer
White to yellow, cross-bedded, medium to coarse sand, with gravel and clay lenses
Red, orange, or brown stain from iron oxides – sometimes cemented with large blocks or layers of ironstone
Clay (gray – unweathered) but usually white where interbedded with the ironstone
15 Site History and Setting Typical subsurface conditions
0-40 ft: “Shallow Cohansey Aquifer” – fine to coarse sand, little to trace fines. Dense iron- cemented sands may be present
40-70 ft (approx.): “Banded Zone” – alternating sand and clay layers. Can prevent shallow contamination from migrating vertically
70-100 ft (approx.): “Middle Cohansey Aquifer” – fine to coarse sand, little to trace fines
16 Site History and Setting
Blackwater Branch stream valley (gentle slope; groundwater discharges to stream from both sides of stream channel; natural hydraulic gradient relatively low)
Blue arrows represent Groundwater Flow direction
17 Site Characterization
Sonic drilling used to install groundwater monitoring wells and collect soil samples.
Soil and groundwater samples collected for characterization and treatability testing
Measured Total Arsenic in soil (mg/kg) and Dissolved Arsenic in groundwater (ug/L)
Method allows for continuous coring and sample collection
Method minimizes air exposure
18 Arsenic Geochemistry and Treatability Testing
USACE evaluated soil and groundwater geochemistry site-wide and its laboratory conducted treatability testing
Concentrations of arsenic in soil, and arsenate and arsenite ions in groundwater
The oxidation-reduction (redox) state of the groundwater aquifer Arsenic Geochemistry and Treatability Testing
Horiba Water Quality Meter
Log field parameters when sampling groundwater
. Temperature . pH
. Oxidation Reduction . Dissolved Oxygen (DO) Potential (ORP)
Field Test Kits
Dissolved Iron and DO
20 Toxicity, mobility, and fate and transport of Arsenic in the environment is complex – minerology, biological, and chemical speciation are factors (Bowell et al, 2014 – free paper on ResearchGate Arsenic © Mineralogical Society of America) Geochemistry “There are 568 known minerals for which arsenic is a critical component - these and Treatability include elemental arsenic, arsenides, sulfides, oxides, arsenates, mixed-anion Testing arsenates, and arsenites.” As (V): Arsenate ion contains arsenic in 5+ state and 4 oxygen atoms
As (III): Arsenite ion contains arsenic in 3+ state and 3 oxygen atoms
As (III) can oxidize to As (V) in the presence of air (lose electrons)
21 Arsenic Geochemistry and Treatability Testing
Biogeochemical Model of the Arsenic – Iron - Sulfide System: Oxidizing Reducing Iron Oxides
(Source: O’Day, P. et al, The influence of sulfur and iron on dissolved arsenic concentrations in the shallow subsurface under changing redox conditions, PNAS, 2004)
22 Arsenic Geochemistry and Treatability Testing
Initially, USACE tested potential chemical fixation reagents, and focused on increasing REDUCING conditions in groundwater to promote sorption of As (III) to iron oxides, since As (III) can substitute for Fe (III) in various mineral structures.
Concluded the large majority of arsenite ions (AsIII) would need to be OXIDIZED to arsenate ions (AsV). Existing dissolved iron will precipitate as iron oxyhydroxide minerals, which will in turn scavenge dissolved arsenic from solution and immobilize it on Anaerobic sample packaging the mineral surfaces through adsorption. to limit oxidation
23 Review by USACE and EPA Region 2 indicated that IN-SITU AIR SPARGING may offer the best oxidation effectiveness.
Air Sparge Pilot Testing Air-in-water aeration is commonly used in water treatment plants. The efficiency of aeration depends on the amount of surface contact between air and water, which is controlled primarily by the size of the air bubble. The higher the pressure, the more readily the transfer of the oxygen to the water.
24 Note: our sparge points were installed in the zone of contamination (and above)
25 OBG was authorized to design, build, and pilot test a Temporary AIR SPARGE system to address a portion of the dissolved arsenic plume
USACE wanted the system to produce these optimal conditions in the aquifer at a depth of 20 - 40 ft below grade: Air Sparge Pilot Testing pH of 6.7
Dissolved Oxygen (DO) of 2 - 4 mg/L
Oxidation-reduction potential (ORP) of +200 to +350 millivolts (mV) – ORP is a measure of the tendency of a chemical species to acquire electrons and thereby be reduced; the more positive the value, the higher the likelihood of reduction
26 OBG designed the system and prepared the Work Plan in accordance with:
Naval Facilities Engineering Command (NAVFAC) 2001 Final Air Air Sparge Pilot Sparging Guidance Document Testing USACE 2001 Engineering and Design Requirements for the Preparation of Sampling and Analysis Plans
USACE 2013 Environmental Quality: In-Situ Air Sparging Engineering (System checklists)
27 System Layout
OBG installed: - 8 stainless-steel Air Sparge wells (AS), only 6 operated at a time - 10 multi-level monitoring points / wells (AS_MP) - 10 piezometers (PZ) - 4 in the sparge area, 2 upgradient, and 4 downgradient.
Installed September 2015
28 Air Sparge Pilot Testing
Typical Air Sparge Well Detail (not to scale)
2”DIA SCH 40 SS Casing / Pipe 2’L 2”DIA SCH 40 SS Wire Wrap Well Screen Slot Size 0.020” Well Cap 1” Sand Pack Bentonite (pellet) seal 95% Portland/5% Bentonite Grout
29 Air Sparge Pilot Testing
Typical Wellhead Piping Detail (not to scale)
Pressure Gauge
Air vent ball valve
Airhose
30 Air Sparge Pilot Testing
Geologic Cross Section
Air Sparge Wells with 2’ screens (green), some multi-level, in zone of contamination Monitoring Points with 5’ screens (blue), all multi-level, above sparge zone
31 Air Sparge Pilot Testing Design and Site Preparation – Clearing And Grubbing Care taken to protect constructed wetlands OBG designed the system and prepared the site adjacent to stream
32 CF05/CF01 (2017-2018) – Air Sparge Pilot Testing Construction – Pipe Rack Installation / Cable Tray
Above grade construction to avoid excavation
33 CF05/CF01 (2017-2018) – Air Sparge Pilot Testing Construction – Electric Service Installation
Subsurface installation of 480V/200A/3-phase service
34 CF05/CF01 (2017-2018) – Air Sparge Pilot Testing Trailer-mounted system built and tested off-site
35 Air Sparge Pilot Testing
Process Flow Diagram (excerpt)
36 Air Sparge Pilot Testing
Trailer Interior
37 Air Sparge Pilot Testing Startup and Commissioning
Sparge testing at various flows, Electrical power connections and piping connections pressures, and intervals
38 Air Sparge Pilot Testing System Performance Testing
Hydraulic Response – assess the timing of air channel inflation and channel breakthrough for various Air Sparge injection wellpoints
Groundwater Quality Response – evaluate the system’s air sparge efficiency
Air Sparge Wellpoint Performance – review air injection pressure and flow to assess changes in cycle times or flow rates, assess need for wellpoint rehabilitation
39 Air Sparge Pilot Testing
System performance testing data collection
System operating data
Wellfield response data
Separate field sheets developed for groundwater well monitoring points and piezometers
40 Air Sparge Pilot Testing Groundwater Monitoring and Sampling Setup
41 Startup testing to confirm aquifer collapse and geochemical Air Sparge Pilot response to air injection Testing Monitor individual Pressure wells and system Optimizing Cycle parameters Flow Time and Air Off-gas temperature Injection Flow Multiple Various individual wells Rates operational scenarios Tested Coupled well operation Pressure and flow modifications
42 The AS system distributes air into the subsurface to fully contact dissolved arsenic and achieve the desired pH and DO conditions for a distance of at least 15 ft from the AS Air Sparge Pilot wells. This was achieved by optimizing the cycle time and Testing air injection flow rates.
OBG has been performing routine O&M of the system Current Status since the startup; this has included training of USACE staff to perform some O&M duties, reducing the overall cost of the program.
43 OBG PRESENTS:| THERE’S A WAY Questions? Thank you!