BDD Water Provides Excellent Quality
General Description of the Water Quality of the Rio Grande at Buckman
The quality of the Rio Grande – LANL-origin radionuclides normally are absent from Rio Grande water and sediment at Buckman except during Los Alamos Canyon flash floods. These man-made radionuclides normally are detected or measured in the Rio Grande in amounts that are indistinguishable form background and are from atmospheric nuclear bomb testing decades ago. Flash floods flowing down the normally dry Los Alamos/Pueblo Canyon drainage to the Rio Grande occasionally transport much higher concentrations to the Rio Grande for a few hours.
The general water quality at the BDD Project’s point of diversion is highly variable. Although it is often relatively clear, the Rio Grande at Buckman may become less clear with suspended sand, silt, clay, natural organic material and microbes. However, neither the river water, the river sediments, nor the river bed typically contain toxic or hazardous substances in toxic or hazardous amounts, nor do they contain measurable radionuclides that are distinguishable from normal background.
However, storm runoff and other runoff such as a water line break can erode and transport contaminated sediments from LANL locations with contaminated soils into the bottoms of the Los Alamos/Pueblo Canyon and its tributaries, and then to the Rio Grande upstream of Buckman. Storm water flows have transported radionuclide and other pollutants to the Rio Grande. Concentrations of contaminants of public concern in the Rio Grande can, for a few hours at a time, exceed the concentrations associated with long-term health-based maximum average exposure limits. This is a matter of BDD Board and public concern, even though the health effects of these radionuclide contaminants are cumulative and chronic, not acute.
Studies have shown that the Rio Grande almost always has water quality that will comply with the most stringent standards advocated for contaminants of LANL origin. However, the BDD Board and Staff must be certain that storm water runoff from LANL is managed and regulated to ensure contaminants are contained on LANL property and do not reach the Rio Grande.
Five Facts that Protect BDD Water Customers
The BDD Project will produce drinking water that complies with all safe drinking water standards based on five facts:
1. The quality of the Rio Grande –The Rio Grande does not contain LANL pollution except during major storm events, which result in significant flows Los Alamos/Pueblo Canyon to the Rio Grande.
2. Reduction of pollution in storm water – The BDD Board and Staff are successfully working with the U.S. Department of Energy (DOE) and LANL and with regulatory agencies to reduce pollution carried by storm water. By this action, they can reduce the migration of LANL-legacy contaminants into the Los Alamos and Pueblo canyons during runoff events to prevent pollution and these types of contaminants from reaching the Rio Grande.
3. Early notification system to stop diversions –The BDD Project intends to manage, and may temporarily cease diversions if an early notification system indicates runoff from Los Alamos/Pueblo Canyon is bringing pollution to the river. The BDD is working with LANL to have this system designed, implemented and maintained.
4. Effective water treatment – Robust water treatment removes LANL contaminants of concern.
5. Timely and transparent monitoring results – River and treated drinking water is sampled, monitored and reported to the public. The BDD Board, as a matter of public policy, provides timely, transparent data regarding river and drinking water quality to the public.
BDD Water Treatment Processes
The BDD Project Water Treatment Plant includes a series of conventional and advanced water treatment processes, beyond those that are commonly used across the nation. The conventional processes remove the vast majority of contaminants. The advanced processes provide additional treatment and polishing of the finished drinking water. Conventional treatment processes include coagulation, flocculation, sedimentation and disinfection. Raw water ozonation improves the effectiveness of conventional treatment. Advanced treatment is provided by membrane filters, ozone and granular activated carbon contactors. Disinfection is accomplished with lower amounts of chlorine because the high-quality water does not need as much chlorine.
Click on the graphic below for more detailed information.
BDD Project Water Treatment Process – Step By Step
1. River water is diverted through a riverside structure with fish screens. Larger sand particles are returned to the Rio Grande and the water is pumped to the Water Treatment Plant.
2. Three presedimentation and raw water storage basins allow remaining larger particles to settle to the bottom for removal.
3. Ozone is added to oxidize organic material. Water is mixed with a coagulant, ferric choride, which causes even the finest particles to clump together.
4. Flocculation provides gentle mixing. The tiny individual particles collide, stick together, and become larger and heavier. Contaminants and impurities are swept up into the flocculated particles.
5. Plate settlers provide very still conditions to separate the heavier floc particles from the water by gravity. The settled solids, called sludge, is concentrated, dewatered in a centrifuge, and hauled to the Caja del Rio landfill.
6. The clarified water is filtered under high pressure through membranes with extremely small pore size, 0.1 microns. This membrane filtration removes essentially all of the particulate matter, including particles that are much smaller than the pore size.
7. Ozone is again applied to the clean water. It oxidizes any dissolved organic material not previously removed and kills microbes. Organic compounds that may cause bad tastes or odors are oxidized (broken down), as are PPCPs (pharmaceuticals and personal care products) and EDCs (endocrine disruptors). Residual ozone is then destroyed.
8. The water passes through GAC (granular activated carbon) contactors. The oxidized organics are removed by the biologically active carbon, which also works as a “polishing” process.
9. Small amounts of chlorine and sodium hydroxide are added to disinfect the water and to correct the pH of the treated water. The finished drinking water is stored in a four-million-gallon tank. Two pump stations pump the treated water north and south to BDD Project drinking water transmission line connections to the City and County public drinking water distribution systems. Chlorine is added as necessary to have a very small amount of residual chlorine in the finished drinking water. This protects against any contamination that might occur.
Surface Water Quality
The BDD Project is committed to ensuring a safe and sustainable surface water supply from the Rio Grande for the Santa Fe community. The BDD Board has been active on many fronts to assure drinking water produced by the BDD Project meets all safe drinking water standards, and scientifically demonstrate that drinking water is safe with respect to LANL environmental pollution in order to improve customer confidence.
The BDD Board advocates that the New Mexico Water Quality Control Commission adopt the New Mexico Environment Department’s proposed standards and criteria for LANL contaminants in the Rio Grande upstream from Cochiti Reservoir so that agencies and consumers have an official public benchmark for their interpretation of water quality information in the future when the Rio Grande becomes the main source of Santa Fe’s public drinking water supply.
The absence of specific health-based standards for these man-made radionuclides makes interpretation difficult or impossible for most consumers, particularly because the lack of a standard can provide an opportunity for misinterpretation. The health-based standards are needed for the source of our drinking water so that simple comparison of water quality with standards will answer the question: does the source water contain harmful substances in harmful amounts?
As stewards of the only drinking water system directly affected by LANL’s radionuclide environmental contamination, the BDD Board also supports NMED’s standard to designate the Rio Grande above the Cochiti Reservoir as a public water supply.
The BDD Board’s support of the New Mexico Environment Department’s (NMED) 2009 Triennial Review of Water Quality Standards is outlined in the Direct Technical Testimony on behalf of the BDD Board.
In a 2007 letter,
the BDD Board requested six actions of the Department of Energy (DOE) and LANL to protect the BDD Project from LANL pollution. The BDD asked LANL to stop or minimize the migration of LANL-origin contaminants to the Rio Grande. Migration occurs via storm water erosion and transport of sediments, which contain adhered contaminants. The NMED has ordered LANL to take steps to reduce contaminated sediment transport in Los Alamos and Pueblo Canyons. These mandatory measures will help realize the BDD’s goal to stop or minimize migration of these contaminants. The BDD Board believes that there are other practical steps that LANL could and should take that would reduce this storm water problem.
In October 2009, the BDD Board sent a letter asking for a Memorandum of Understanding with the BDD Project describing the DOE and LANL commitments with regard to the six action steps, including an updated status of the six action steps as of September 2009. The current status is summarized in the next section, BDD Asks LANL to Ensure Water Quality.