Source Water Protection and Detection of Chemical Contaminants
NC AWWAWEA 2015 Annual Conference November 16, 2015 Source Water Protection and Detection of Chemical Contaminants Ben Wright Ben Stanford Alison Reinert Overview Source water protection drivers Data resources Assessing risk
Emergency response and risk mitigation Early warning and detection Drinking Water Treatment
Treatment plants are typically designed to remove turbidity, pathogens, natural organic matter, and some limited inorganics Chemical Contamination
Petroleum hydrocarbons Industrial chemicals Pesticides Chemical and Petroleum Treatment
Treatability depends on chemical characteristics Dedicated treatment for chemical or petroleum contamination requires multiple processes to remove specific contaminants Dedicated treatment for chemical spills at WTPs is expensive and impractical Other issues include decontaminating plant and disposing of contaminated residuals Chronic Contamination
Low concentrations of chemical contaminants may be attenuated naturally through dilution, adsorption, volatilization, degradation, etc. Too many low concentration inputs can overwhelm natural processes Groundwater contamination has less chance of natural attenuation, so if the release is in proximity to a well, risk of contamination is high Acute Contamination Releases of large quantities of chemicals can make surface water supplies unusable for a period of time Recent eventshave highlighted vulnerabilities for many water supplies: Elk River, WV (chemical spill) Danville, VA (coal ash spill) Lynchburg, VA (crude oil train derailment) St Charles Parrish, MS (barge oil spill) Kalamazoo, MI (oil pipeline failure) Groundwater utilities will tend to be more resilient to these large surface water releases, but impacts may be possible due to location/dpeth of well, hydrogeology, nature of spill, etc. Source Water Assessments
1996 amendments to the SDWA, placed new emphasis on source water protection Required states to develop programs to assess the susceptibility of source waters to contamination Risk profiles change over time New/different sources of industrial pollution Changing land uses Response measures may not currently be adequate (i.e. increased demands) Regulatory landscape may be different (MCLs) New regulations in NC will require more from individual utilities A spill can make a water supply unusable for many days NC Source Water Assessment Program
Two component contamination susceptibility rating Inherent vulnerability rating Contaminant rating based on density and relative risk of potential contamination sources Overall susceptibility rating based on combination of the two ratings Surface Water Source Characteristics Vulnerability Higher Moderate Lower Watershed Classification X Intake Location Treatment plant raw water quality data Watershed Characteristic Evaluation Source Water Protection Planning Steps
Characterize the watershed and identify risks Set goals and identify solutions (response and mitigation) Design an implementation program Build partnerships Implement the plan Measure progress Re-evaluate plan and make adjustments This talk is focused on chemicals, but these are the steps that would be followed regardless of the type of contamination Watershed Characterization Data Sources
Access to GIS data and many government databases have increased ability to efficiently map potential sources of contamination State and Federal government databases of georeferenced data to ID potential sources of contamination (PSC) USEPA Envirofacts Toxic Release Inventory, NPDES and other permits USDOT Pipeline mapping NJDEP Pollutant Discharge Elimination System database NJDEP Data Miner app NJDEP Land Use/Land Cover GIS data Note data reliability Data Sources with Limited Availability
Transportation networks (rail and highway) Specific chemicals stored at industrial facilities Available per EPCRA Limited online availability Self-reported data May be redacted due to trade secrets Note data reliability Assessing Risk Many watersheds have hundreds of potential contaminant sources, many with unknown type/volume of material What is the chance that chemicals will get to your intake or well in high enough concentrations to cause an impact? Overall risk is based on both high risk sources and effectiveness of response measures Not all sources are high risk, important to identify the ones that are The number of PSCs can be overwhelming Older facilities are more likely to have older or failing secondary containment, aging pipes, etc. Typically releases are unrelated, but is there a possibility of weather events like floods that could cause multiple releases simultaneously Assessing Risk - sources
Factors affecting risk How close/how concentrated are PSCs Surface vs underground storage Age of facilities History of releases River/reservoir/ groundwater dynamics Natural attenuation SARA Title III tier II reports Assessing Risk - responses
How confident of notification in a timely manner What are the existing communication protocols between industry, regulators, utilities, etc. Are they tested regularly (e.g. mock spill) What is your ability to maintain deliveries during an incident Storage capacity (raw and finished) Demand levels (seasonal, peak) Effective treatment processes Availability of lab resources Specialized lab resources can be difficult because the tests required for particular chemicals may not be common Ability to run jar tests or simulate treatability beforehand is beneficial Emergency Response Measures
Shutdown intakes / turn off wells Typically least expensive Effective, but reduces supply reliability Requires sufficient storage for duration of shutdown Emergency conservation can result in short term spikes in usage Emergency treatment High cost Effectiveness dependent on chemical properties (no silver bullet) Alternate water supply from different source High cost to maintain redundancy May provide resilience to other emergencies (drought) One thing to keep in mind is that costs incurred may be able to be reimbursed by the responsible party Risk Mitigation Develop relationships with key industrial PSCs
Encourage direct line of communication for spills Work with other utilities to share resources Implement an early warning system Develop contacts to build a knowledgebase University professors and researchers Poison Control Centers Specialized consultants Communicate with regulators beforehand to identify response measures, treatment targets, recovery plan, etc. and get support for plans Work with basin stakeholders for education and public outreach Utilities have no authority over PSCs, but can work to improve notification and boost preparedness Perhaps speak with regulators about high risk sources that are close and have large volumes of chemicals Early Warning and Detection Technologies
Commercial Technologies Wide price range$50-$70,000 In-situ and ex-situ sampling Grab and online monitoring Fluorescence Purge and trap (GC-MS) Fiber optics Detection strips Light pulsation Absorption Film detection Liquid detection Comparison of Detection Technologies
There are numerous sensor technologies on the market that provide different capabilities ata range of costs Accuracy and Range Specific costs will depend on data loggers and other extras needed for the installation Capital and O&M costs Comparison of Detection Technologies
Optical Sensors Cost $8k to $15k Ex. Petrosense DHP 485 PPM level detection of TPH and BTEX submersible unit that has no consumables minimal maintenance Accuracy and Range Capital and O&M costs Comparison of Detection Technologies
Fluorescence Sensors Cost $20k to $30k Ex. TD 4100 XDC PPB level detection of chemicals or petroleum Cannot detect for multiple chemicals at same time Can be recalibrated quickly Moderate regular maintenance Accuracy and Range More detection flexibility at a higher cost and more maintenance Capital and O&M costs Comparison of Detection Technologies
Gas chromatograph Sensors Cost >$50k Ex. Inficon CMS 5000 PPT level detection of chemicals and petroleum Higher cost and level of maintenance Recommended for when it is necessary to regularly monitor for a range of constituents Accuracy and Range Capital and O&M costs Selected Additional Resources
AWWA G Standards for Source Water Protection J Risk Analysis and Management for Critical Asset Protection (RAMCAP) Water Research Foundation Project 4176: Developing a Vision and Roadmap for Source Water Protection for U.S. Drinking Water Utilities USEPA A Water Security Handbook: Planning for and Responding to Drinking Water Contamination Threats and Incidents Couldnt cover everything in this talk, but there are a number of excellent resources on swpp in general, emergency response and maintaining resiliency of drinking water systems Questions? Ben Wright, P.E. (410)