Presented to the AEHS 2018 Conference San Diego, California March 21, 2018 Unintentional Discharges of Industrial Compounds to Sanitary or Stormwater Drainage Systems in Urban Settings Olivia P. Jacobs; Clearwater Group James A. Jacobs; Clearwater Group Harry O’Neill ; Beacon Environmental Services, Inc. Ryan Schneider; Beacon Environmental Services, Inc. 1
Unintentional Discharges to Groundwater and Sewer Laterals defined by Sampling Sewer Air Sanitary and Storm Mains with TO-17 Clearwater and Beacon, 2018 2
Current SCM of leaky sewer pipes From EPA 3
Where pipes intersect with groundwater, it intrudes into sewer pipes Example of PCE release; Where leaky pipes intercept PCE plumes, PCE is discovered in the sewer air PCE GW plume Clearwater and Beacon, 2018 4
Basis for Sampling Sewer Air 1. Presume PCE content in liquid is 1.64 µg/mL 2. Henry’s Law projects 500 µg/m³ in sewer air 3. Where lid is closed, assume equilibrium. 500 µg/m³ PCE in sewer air 1.64 µg/mL PCE in sewer liquid Manhole Pipe Run Clearwater and Beacon, 2018 5
Samplers set in Closed Manholes approximately 12ʺ below the Manhole Lid Manhole Set with TO-17 sewer sewer air liquid Pipe Run Clearwater and Beacon, 2018 6
Passive Samplers – Principles of Operation Axial type samplers For application of Fick's First Law to a diffusive sampler several simplifying assumptions are necessary: 1. That there is an ambient concentration of the analyte at the surface of the monitor (C amb ); that is, does not take matter from its surrounding environment faster than it can be replaced. Clearwater and Beacon, 2018 7
Passive Samplers – Principles of Operation Additional simplifying assumptions are necessary: 2. Zero concentration of the analyte at the surface of the sorbent; that is, the adsorbent is a zero sink and therefore there is no saturation of the adsorbent (C ads = 0) 3. A linear concentration gradient between the two. Steady state conditions always exist. Clearwater and Beacon, 2018 8
VOCs in air in sewer mains and laterals – Historic discharge and pipes run through TCE plume Included in Roghani et al., STOTEN, 2018. 9 Clearwater and Beacon, 2018
(Lab) TO-17 Passive Sorbent • Period of exposure depends on lab level of detection. • Beacon supported this project Passive Sampler – TO-17 Durable in Suspended sewer in indoor air environment environment Clearwater and Beacon, 2018 10
Deploying TO-17 Sampler in a Manhole Clearwater and Beacon, 2018 11
Example Manhole Appearance www.sswm.info Manhole example in photo is about 2 ´ deep. Clearwater and Beacon, 2018 12
Example Manhole Sampling Appearance Sampler set in manhole Sewer Air Sewer Liquid 13
Detective work - any discharged compound? Knowing the compound … Carwash discharges cleaners into the Manhole sanitary sewer Main ? Lateral Will we detect it in the Sewer Air in the upstream or downstream manhole? Clearwater and Beacon, 2018 14
Evaluation of Sewer Air for known Discharges - Proof of Concept • If VOC Plumes intersecting Leaky Sewer Pipes result in VOCs in Sewer Air … • Does unintentional discharge to laterals or interception of other groundwater plumes result in Sewer Air Contamination in the sewer mains serving the site with discharged compounds? Clearwater and Beacon, 2018 15
Types of Compounds we might want to know are in the sewers • Illegal Substances (meth production) - to identify nascent social problems • Known IA contaminants (compounds) - since sewer air can become IA • Explosives - to prevent hazards Clearwater and Beacon, 2018 16
Known discharge (by-products of producing meth) into the sanitary sewer … Manhole Clean Out Main ? ? Lateral What will be detected in sewer air? Clearwater and Beacon, 2018 17
Ubiquitous Non-Drycleaner Compounds Which are an IA-concern Groundwater plumes with petroleum constituents. Where groundwater infiltrates sewer pipes as they intersect the plumes of elevated benzene, toluene, ethylbenzene … Are these compounds in the sewer air? Clearwater and Beacon, 2018 18
Test a Typical Active Commercial Strip – Sewer Mains for IA compounds 19 Clearwater and Beacon, 2018
Lateral Locations and Sampled Manholes Symbol Key Sewer Lateral Location of Contributing Laterals should define the Location of Compounds in the Sewer Air Clearwater and Beacon, 2018 20
Plumes enter the Pipes which are below the Groundwater X-section of sanitary sewer pipes, ground water level and ground level The Plan View is Provided Below Clearwater and Beacon, 2018 21
Lateral elevations v. GW elevation Surface Elevation of manhole 10 Groundwater elevation 5 * * * * Elevation of sanitary 0 sewer main Approximate location of lateral/main connection * -5 Elevation of lateral (standard depth) at 3 feet bgs Feet amsl Lateral Trench to main Tie-in Note that sewer main was replaced in 1990, but laterals could date back to the 1940s. Clearwater and Beacon, 2018 22
Contaminant Plumes per Geotracker 1 2 3 Symbol Key Groundwater Historic Groundwater Flow Directions Contaminant According to Release #1 data Plumes in Fill in Bay Mud Clearwater and Beacon, 2018 23
Elevated Sewer Air Contamination Anticipated (per 3 releases) 1 2 3 Clearwater and Beacon, 2018 24
Compounds identified in Sewer Air • Chloroform • Carbon Tetrachloride • Benzene • Toluene • Ethylbenzene • Xylenes No TPH! Clearwater and Beacon, 2018 25
IA Compounds of Concern identified in Sewer Air Three Compounds above IA ESLs • Benzene IA ESL 0.097 µg/m³ • Chloroform IA ESL 0.12 µg/m³ • Carbon Tectrachloride IA ESL 0.067 µg/m³ Note - These only matter where sewer air is directly entering into living spaces. Clearwater and Beacon, 2018 26
Benzene Measured in the Sewer Air 0.85 1.04 0.89 1.68 1.04 1.49 2.23 2.21 Clearwater and Beacon, 2018 27
Benzene Measured in the Sewer Air Compound Benzene 0.0 ? in µg/m³ In Indoor Air 0.85 ESL 0.097 µg/m³ 1.04 0.0 ? 0.89 0.0 ? 1.68 1.04 1.49 2.23 1.0 2.0 2.21 0.0 ? 28 Clearwater and Beacon, 2018
Carbon Tetrachloride in the Sewer Air 1.99 2.96 <0.15 Compound 4.26 12.37 Carbon 0.77 235.17 Tetrachloride 29.54 In µg/m³ In Indoor Air ESL 0.067 µg/m³ Clearwater and Beacon, 2018 29
Contours of Carbon Tetrachloride 1.99 1.0 ? 2.96 <0.91 1.0 10.0 100.0 4.26 12.37 1.0 ? 0.77 235.17 29.54 1.0 ? 1.0 ? Clearwater and Beacon, 2018 30
Chloroform in the Sewer Air 1.23 3.43 <1.17 33.43 Compound 16.92 146.65 3.89 Chloroform In µg/m³ 32.65 In Indoor Air ESL 0.12 µg/m³ Clearwater and Beacon, 2018 31
Chloroform Contour in the Sewer Air 1.23 1.0 ? 3.43 <1.17 3.89 33.43 16.92 146.65 10.0 32.65 100.0 1.0 ? 10.0 1.0 1.0 ? 32 Clearwater and Beacon, 2018
Benzene along the Sewer Main vs ESLs 0.85 1.04 0.89 1.04 1.68 2.21 2.23 1.49 2.25 2.00 1.75 1.50 1.25 1.00 0.75 0.50 0.25 0.00 Clearwater and Beacon, 2018 33
Chloroform Along the Sewer Main 1.23 3.43 16.92 33.43 3.89 146.65 32.65 150 135 120 105 90 75 60 45 30 15 0 Clearwater and Beacon, 2018 34
Carbon Tetrachloride Along the Sewer Main 1.99 2.96 12.37 4.26 0.77 235.17 29.54 250 225 200 175 150 125 100 75 50 25 0 Clearwater and Beacon, 2018 35
Exposure Levels from Sewer Air • Benzene – all of the manholes had levels 10X ESLs • Chloroform – 7 of 8 manholes had x10 ESLs 3 of 8 had x100 ESLs 1 of 8 had x1000 ESLs • Carbon Tetrachloride – 7 of 8 had x10 ESLs 3 of 8 had x100 ESLs 2 of 8 had x1000 ESLs 1 of 8 had x10,000 ESLs Clearwater and Beacon, 2018 36
Exposure - Where SA moves into IA Research by others suggests a 1:10 attenuation between manhole and IA. To evaluate the risk from the compounds in sewer air at this site, • Benzene is at ESL threshold • Chloroform is at up to 100X ESLs • Carbon Tetrachloride is at up to 1,000X ESLs Clearwater and Beacon, 2018 37
Exposure – Where Sewer Air reaches IA Benzene , Pump Station (line ends) Residential Carbon Tetrachloride Chloroform 0.85 ESL IA 0.097 levels in sewer air in 1.99 ESL IA 0.067 Sewer lines serving 1.23 ESL IA 0.12 Residential areas Commercial Note: 1.04 ESL IA 0.097 Commercial washroom 2.96 ESL IA 0.067 3.43 ESL IA 0.12 exposures are not Commercial followed since 1.04 ESL IA 0.097 12.37 ESL IA 0.067 duration of 2.23 ESL IA 0.097 16.92 ESL IA 0.12 exposure is 235.17 ESL IA 0.067 146.65 ESL IA 0.12 small. Clearwater and Beacon, 2018 38
Exposure = Leaky Plumbing + negative IA pressure Benzene in Failed Plumbing Seal the Sewer Main Exhaust Air. Fan From City of Newport News, VA Clearwater and Beacon, 2018 39
For future research - Stormwater/Sanitary Air Relationship (Benzene) 0.85 1.04 0.89 1.68 1.04 2.23 Single 1.49 ? ? 2.21 stormwater 0.82 manhole air sample result Note that the stormwater manhole air benzene value and the first and last sewer air samples are virtually the same. Agency has no map of connectivity. Clearwater and Beacon, 2018 40
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