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