Monday, September 17, 2018

Let the Septic System Recover after the Flood

After flood waters recede septic systems should not be used immediately. Drain fields will not work until underground water has receded and the soil has dried out. Whenever the water table is high or your septic drain field has been flooded, there is a risk that sewage will back up into your home. Though septic lines may have broken during the flood it is more likely that the lines were just submerged.

The only way to prevent a flooded system from backing up is to relieve pressure on the system by using it less- so do not allow your tank to pump or drain to the drain field until the soils dry out. Basically, there is nothing you can do but wait, do not use the system if the soil is saturated and flooded. The wastewater will not be treated and will become a source of pollution, if it does not back up into your house, it will bubble up into your yard. Conserve water as much as possible while the system restores itself and the water table fails.

Do not return to your home until flood waters have receded. If there was significant flooding in your yard, water will have flooded into your septic tank through the top. The tops of septic tanks are not water tight. Flood waters entering the septic tank will have lifted the floating crust of fats and grease in the septic tank. Some of this scum may have floated and/or partially plugged the outlet tee. If the septic system backs up into the house check the tank first for outlet blockage. Remember, that septic tanks can be dangerous, methane from the bacterial digestion of waste and lack of oxygen can overwhelm you. Hire someone with the right tools to clear your outlet tee.

Do not pump out the septic tank while the soil is still saturated. Pumping out a tank that is in saturated soil may cause it to “pop out” of the ground. (Likewise, recently installed systems may “pop out” of the ground more readily than older systems because the soil has not had enough time to settle and compact.) Call a septic service company (not just a tank pumping company) and schedule an appointment in a few days. Do not use the septic system for a few days (I know) have the service company clear any outlet blockage, or blockage to the drain field, check pumps and valves and partially pump down the tank if your soils are not dry enough or fully pump the tank if the soil has drained enough. The available volume in the tank will give you several days of plumbing use if you conserve water to allow your drain field to recover. Go easy the septic system operates on the principals of settling, bacterial digestion, and soil filtration all gentle and slow natural processes that have been battered by the storm.

Wednesday, September 12, 2018

Florence Preparation for Well Owners

Erin Ling with the Virginia Household  Water Quality Program out of Virginia Tech sent out a draft fact sheet from our Extension colleagues at Texas A & M and University of Florida as well as Kelsey Pieper here at Virginia Tech developed during their experiences providing private well outreach and assistance during last year's devastating hurricanes.  
You may find it helpful as Florence approaches this week.

How to prepare your well for flooding: Evacuation Preparations and Return Home
You can take action to better prepare your well for a flood, even as you are making plans to evacuate.  Store adequate bottled water for drinking and cooking because you won’t be able to drink, brush teeth or cook with the well water until it is tested and found suitable. Complete the following during your evacuation planning:
During Potential Evacuation Preparations
1.       Locate a nearby water testing lab to obtain sample collection bottles and instructions. Frequently, the health department can test your water for bacterial contamination. If there is not a health department near you, your county Extension agent can put you in touch with laboratories that test water quality.
2.       Locate the log/well report completed when the well was established and store a copy of it in a safe place that will be accessible if you evacuate.
3.       Locate contact information for licensed well drillers in the area. Contact a driller/s before evacuating if you think your well will need service immediately after the flood. It may be difficult to schedule service after the storm.
4.       Fill up the pressure tank as much as possible.
5.       Turn off the electricity to the well.
6.       If you have an aerobic septic system, turn off the electricity for the system. No special preparations are recommended for conventional septic systems.
7.       If you plan to attempt to disinfect your well yourself upon your return, have these basic shock chlorination materials available before the flood because these supplies may be difficult or time-consuming to acquire following a flood:

a.       Instructions on how to shock chlorinate 
b.      Unscented, liquid bleach
c.       Clean five-gallon bucket and five gallons of uncontaminated water
d.      Garden hose that reaches from an outdoor faucet to the well
e.       Protective goggles and gloves
f.        Wrench for well access
g.       Funnel
h.      Hose
i.         Sample collection bottles from local water testing laboratory.

8.       Learn how to bypass water softeners and household water filters if any are attached to your water system. Read and have manufacturer’s instructions easily available on how to disinfect bypassed water softeners and household water filters. Disconnect water treatment and drain before evacuating.

Upon Return
If you've never disinfected a well, It is strongly recommended that a licensed water well driller be hired to shock chlorinate the well if it has been flooded. A water well driller will have access to more effective products and will have equipment and experience that a typical well owner will not have. However, I know how difficult it is to find a well driller who is available in the middle of an emergency. So, if you plan to attempt to disinfect your well yourself, follow the instructions carefully be methodical and you can do it. Remember you need power to have been restored to disinfect a well.

Monday, September 10, 2018

Using AI to Find the Lead Pipes in Flint

The story of the Water Crisis in Flint Michigan has many facets that began decades earlier with the slow decline of the city. For decades short sighted decisions were made, the city failed to maintain and update their water infrastructure. Then when the city fell towards bankruptcy, Flint decided to switch the City’s water source in a cost saving measure from the old Detroit system to the Flint River as a water source.

The Flint Water Treatment staff and their consultants struggled to meet the Safe Drinking Water Act levels at the water treatment plant. Then residents noticed unpleasant changes in the smell, color, and taste of the water coming out of their taps. Tests showed high levels of bacteria that forced the city to issue boil advisories. In response, the city upped its chlorine levels to kill the pathogens. This created too many disinfectant byproducts, which are carcinogens and corrosive. Then the corrosive water began leaching lead, other metals and whatever else was in the biofilm on the old pipes into the water in the homes.

Flint’s water department might have been able to avert this disaster by having a corrosion management plan and using additives to diminish the corrosiveness of the water at a negligible cost, but there was an underlying problem that effects not only Flint-lead service lines- the lines that connect homes to the city water system.

By 2016 replacing the service lines became a top priority for the City of Flint. Though, technically, these lines are owned by the homeowner, the Michigan state legislature appropriated $27 million towards the expense of replacing these lines and later the U.S. Congress allocated almost another $100 million for Flint.

With money in hand the problems became that the City of Flint did not know how many lead service lines existed and where they were located. Service line information are theoretically documented during original construction or renovation in the building department files, but those records were found to be incomplete or lost.

Because digging up an entire water service line pipe under a resident’s year cost thousands of dollars, unnecessarily digging up a line that turns out not to be a lead service line is wasteful and the city did not have money to waste. Flint believed there might be as many as 50,000 homes potentially needing service line replacements, the city was facing costs up to $250 million.

Google believed data science could expedite the process of identifying specific homes in need of replacement service lines and donated to the University of Michigan and Flint’s Community Foundation. Dr. Jacob Abernethy, then an assistant professor at University of Michigan and now with Georgia Tech, and his Data Science Team of students were called in. With the help of who digitized a set of over 100,000 index cards, water sampling data, and hand-annotated maps digitized by the University of Michigan-Flint GIS Center, Dr. Abernethy and his team were able to analyze the available data to provide statistical and algorithmic support to guide decision making and data gathering. 

Dr. Abernethy and his team developed a machine learning program and statistics to accurately estimate the locations of home needing lead service line replacement as well as those with safe pipes. Their predictive model was found to be empirically accurate for estimating whether a Flint home’s pipes were safe/unsafe with an accuracy rate of 97%. The team estimated that this increase in accuracy would save the City of Flint about $10 million which could be used to replace the pipes at an additional 2,000 homes. This model can be used in other cities to help them identify and replace their lead service lines most cost effectively.

To read the full article:

Jacob Abernethy, Cyrus Anderson, Chengyu Dai, Arya Farahi, Linh Nguyen, AdamRauh, EricSchwartz, WenboShen, GuangshaShi, JonathanStroud,etal. 2018. ActiveRemediation: The Search for Lead Pipes in Flint, Michigan. arXiv:1806.10692v2 [cs.LG] August 2018.

Thursday, September 6, 2018

Dead Zone 2018 Smaller than Predicted

This past spring Ecologists from the University of Michigan and the University of Maryland Center for Environmental Science were forecasting that the Chesapeake Bay would have a larger-than-average “dead zone” in 2018, due to increased rainfall in the watershed this spring.

In the Spring the scientists thought that this summer’s dead zone, an area of low to no oxygen that can kill fish and other aquatic life, would be about 1.9 cubic miles, according to their June forecast.

However, when the Maryland Department of Natural Resources actually performed their July measurements they found the opposite. Due to extreme summer weather, dissolved oxygen conditions in Maryland’s portion of the Chesapeake Bay mainstem were the best ever observed in late July, reported the Maryland Department to Natural Resources. The department tracks hypoxia throughout the summer during twice monthly monitoring cruises.

The hypoxic water volume (areas with less than 2 mg/L oxygen) was 0.26 cubic miles a fraction of the June prediction. This good news was likely the result of the massive rainfall in central and northern Maryland and Pennsylvania (and the whole region), which resulted in near maximum monthly water flows throughout the watershed. This wall of freshwater, accompanied by sustained winds of 20 knots before sampling, reduced stratification of the water column and mixed oxygen well into the system. 

Measurements of the Chesapeake Bay’s dead zone go back to 1950, and the 30-year mean maximum dead zone volume is 1.74 cubic miles. Dead zones are a yearly occurrence in the Chesapeake Bay and other estuaries. Dead zones form in summers when higher temperatures reduce the oxygen holding capacity of the water, the air is still and especially in years of heavy rains that carry excess nutrient pollution from cities and farms. The excess nutrient pollution combined with mild weather encourages the explosive growth of phytoplankton, which is a single-celled algae. While the phytoplankton produces oxygen during photosynthesis, when there is excessive growth of algae the light is chocked out and the algae die and fall from the warmer fresh water into the colder sea water. The phytoplankton is decomposed by bacteria, which consumes the already depleted oxygen in the lower salt level, leaving dead oysters, clams, fish and crabs in their wake.

In a wedge estuary such as Chesapeake Bay where the layers of fresh and salt water are not usually well mixed, there are several sources of dissolved oxygen. The most important is the atmosphere. At sea level, air contains about 21% oxygen, while the Bay’s waters contain only a small fraction of a percent. This large difference between the amount of oxygen results in oxygen naturally dissolving into the water. This process is further enhanced by the wind, which mixes the surface of the water. Scientists are still studying the impact of the winds in delivering oxygen to various water layers. The other important sources of oxygen in the water are phytoplankton and aquatic grasses which produce oxygen during photosynthesis, but when they die consume oxygen during decomposition by bacteria. Finally, dissolved oxygen flows into the Bay with the water coming from streams, rivers, and the Atlantic Ocean.

Bottom dissolved oxygen concentrations in the Chesapeake Bay have continued to increase since 2014, and last year we recorded the second-smallest hypoxic volume ever according to the Resource Assessment Service at the Maryland Department of Natural Resources. Great strides have been made in reducing nutrient pollution from point and non-point sources, though more work needs to be done.

Monday, September 3, 2018

The Red Tide in Florida 8 months and counting

A Red Tide, a harmful algal bloom that at high concentrations discolors the water , is currently affecting about 145 miles of the southwest coast of Florida. Karenia brevis the algae that causes red tides produces nuerotoxins that can cause fish kills, respiratory irritation, and mortality of sea turtles, manatees, and dolphins. This has been a particularly long Red Tide. It started in October 2017 and continued through spring of 2018, and by early summer had re-surged and was detected in five southwest Florida counties.

Red Tides form in the Gulf Coast mostly in Florida and Texas. They are caused by the rapid growth of the microscopic algae called Karenia brevi and generally form more than 40 miles from the Florida coast. When large amounts of this algae are present, it can cause a harmful algal bloom that has be seen from space. Karenia brevi at high concentrations discolors water often red, but also light or dark green or even brown. No single factor causes a Red Tide. The algae bloom needs the organism, Karenia brevi, natural or man-made nutrients for growth, the right concentration rain and sunlight and transport from the wind and waves. No single factor causes it.

The Florida Department of Health reports that tests are being conducted to see if coastal nutrients enhance or prolong blooms. However, it seems logical that man-made nutrients do encourage and feed growth. We know that man-made nutrients feed algal blooms elsewhere. Not all algal blooms are harmful. Many ocean algae blooms are beneficial because the algae provide food for ocean animals and essential part of the ocean food web.

A small percentage of algae, however, produce powerful toxins that can kill fish, shellfish, mammals, and birds, and may directly or indirectly cause illness in people. Algae blooms of non-toxic species can have harmful effects on marine ecosystems. For example, the “Dead Zone” in the Chesapeake Bay when masses of algae die and decompose, the decaying process can deplete oxygen in the water, causing the water to become so low in oxygen that animals either leave the area or die.

The Florida Red Tide organism, Karenia brevis, produces potent neurotoxins, called brevetoxins, that can affect the central nervous systems of many animals, causing them to die. That is why Red Tides are often associated with fish kills and the death of other species, including manatees, dolphins, sea turtles, and birds. In the 16th century a Spanish explorer recorded stories by Florida Indians of toxic "red water" and the resulting death of birds and fish.

Wave action near beaches can break open Karenia brevi cells and release the toxins into the air, leading to respiratory irritation. For people with severe or chronic respiratory conditions, such as emphysema or asthma, the Red Tide can cause serious illness. People with respiratory problems should always avoid affected beaches during Red Tides.

The Red Tide toxins can also accumulate in filter-feeder mollusks such as oysters and clams, which can lead to neurotoxic shellfish poisoning in people who consume the contaminated shellfish. Neurotoxic shellfish poisoning is not fatal, but hospitalizations occur. According to the National Institute of Health neurotoxic shellfish poisoning involves a cluster of gastrointestinal and neurological symptoms: nausea and vomiting, paresthesias of the mouth, lips and tongue as well as distal paresthesias, ataxia, slurred speech and dizziness. Neurological symptoms can progress to partial paralysis; respiratory distress has been recorded. In most cases only diarrhea is reported.

Rigorous state monitoring of water and shellfish assures that commercial shellfish is safe, often by closing harvest beds. Commercially available shellfish in restaurants and grocery stores is safe because it comes from water free of Red Tide and is monitored. Recreational harvesters have the greatest risk of neurotoxic shellfish poisoning, often due to a lack of awareness of the problem.

Red Tides are a natural phenomenon that require the right conditions to expand and linger. This Red Tide is unusual but not unprecedented in its duration. In 2005, a Red Tide started off the coast of St. Petersburg, Florida, in January and then spread to Pensacola and Naples by October, persisting for the majority of the year. In the 1994 there was a Red Tide that lasted 2 years. Since the late 1990's Red Tides have occurred each year. The last protracted period of red tides occurred in the 1870's.The duration of a bloom in nearshore Florida waters depends on physical and biological conditions that influence its growth and persistence, including sunlight, nutrients, and salinity, as well as the speed and direction of wind and water currents.

There are currently no means of controlling the occurrence of red tide, research continues in hopes of finding ways to better address the causes and effects of Red Tides and other harmful algal blooms.

Thursday, August 30, 2018

Groundwater the Foundation of Sustainability

To be sustainable, a population must live within the carrying capacity of its ecosystem, which represents a form of natural capital. One of the most important elements of the ecosystem is potable water. Without water there can be no life. As populations grow water is needed for drinking, bathing, to support irrigated agriculture and industry. Water is connected to all aspects of life on earth-the ecosystem, food, biodiversity, economy and society.

Unlike other natural resources or raw materials, groundwater is present throughout the world. Possibilities for its use vary greatly from place to place, owing to rainfall conditions and the distribution of aquifers (rock and sand layers in whose pore spaces the groundwater sits). Generally, groundwater is renewed only through precipitation, but can be abstracted year-round. Provided that there is adequate replenishment, and that the source is protected from pollution, groundwater can be abstracted indefinitely at a sustainable rate.

Groundwater forms the invisible, subsurface part of the natural water cycle, in which evaporation, precipitation, seepage and discharge are the main components. The “visible” components are all strongly affected by weather and climate, and although they can be contaminated quickly, they generally recover quickly too. By contrast, the subsurface processes of groundwater are much slower and longer lasting, ranging from years to millennia. However, with careful management, these different timescales can be used to create an integrated system of water supply that is robust in the face of drought.

The groundwater cycle in humid and arid regions differ fundamentally from each other. In humid climates, with high rainfall, large volumes of water seep into the groundwater, which contributes actively to the water cycle feeding streams, springs and wetlands during periods when the rainfall is lower. In semi-arid and arid climates, there is by contrast practically no exchange between the surface water and groundwater because the small volume of seepage from the occasional rainfall only rarely penetrates the thick and dry (unsaturated) soils. The groundwater is much deeper and isolated from surface contact. In these areas groundwater resources are only minimally recharged. Our understanding of the complete water cycle is only rudimentary.

Any attempt to accurately model the groundwater component of the water cycle requires adequate measurements and observations over decades. We are beginning to gather that data and improve the modeling of water resources which have incredible variability across the globe and with changing land use and climate.

Groundwater availability varies by location. Precipitation, soil type and land cover like roadways and buildings, forests, and agricultural fields,  determines how much the shallower groundwater is recharged annually. However the volume of water that can be stored is controlled by the reservoir characteristics of the subsurface rocks. Groundwater may be present today even in places with very dry climates because of the nature of the local geology and the historic climate cycles that have occurred through time. Insufficient water due to prolonged drought has contributed to the collapse of ancient civilizations.
In the north-eastern Sahara, the Nubian Sandstone Aquifer System underlies an area of more than 750,000 square miles in Chad, Egypt, Libya and Sudan, and still contains huge amounts of fresh groundwater. Giant groundwater deposits of comparable size and limited recharge are thought to exist on nearly all continents, but the amount of groundwater that can be pumped out is unknown.
Water resources can be used sustainably only if their volume and variation through time are understood. However such information is often lacking, even in so-called developed regions. Hydrology as a science is very young and so little is known. Groundwater in arid regions is finite and non-renewable given the earth’s current climate and the projections scientists are making for the climate in the near future. As droughts and water shortages appear the value of groundwater has begun to be more fully appreciated. Precious groundwater resources increasingly need to be well managed to allow for sustainable long-term use.

Groundwater is usually cleaner than surface water, but that too, is changing. Groundwater is typically protected against contamination from the surface by the soils and rock layers covering the aquifer. This is the only available clean drinking water in many parts of the world. However, rising world population, changes in land use and rapid industrialization increasingly place groundwater in jeopardy. Once contaminated, groundwater is very difficult to clean and often after removal of contaminated plumes only long term abandonment of use to allow for natural attenuation is the only possible course of action.

The demand for water is rising as population, economic activity and agricultural irrigation grow. However, worldwide resources of accessible water are decreasing, due to overuse or pollution. The balance between demand (consumption) and supply (resource) is becoming unstable. More than 30 countries suffer from serious chronic water shortage, and groundwater is increasingly being used to cover the demand.

Monday, August 27, 2018

Where does the Lead in Wells Come From

In 2012, the Macon County Health Department in North Carolina discovered county-wide water lead contamination in private wells due, they reported, to corrosion of galvanized well components. In North Carolina current well construction code requires the installation of a tap on the well; thus, they were able to differentiate lead contamination originating from household plumbing and lead contamination originating from the well.

They found "first draw samples" collected at the wellhead between 2008 and 2012 documented that 55 of 398 (14%) of newly constructed wells exceeded the U.S. Environmental Protection Agency Lead and Copper Rule action level for lead of 15 μg/L. However, there is no safe level of lead exposure, as even low water lead levels-those less than 5 μg/L- can increase a child's blood lead level. In the Macon County Health Department samples they found water with lead concentrations as high as 191 μg/L.

North Carolina like most of the eastern seaboard states has areas at high risk for corrosive water. During periods of stagnation, in water that is corrosive (with a pH less than 6) a chemical redox reaction occurs that dissolves and leaches lead into the water. Lead present in well and plumbing components is leached into the water. This lead comes from brass fittings and galvanized pipe (which has a lead- zinc coating), and plumbing components produced before 2014 when "lead-free" fixtures could have up to 8% lead. In Virginia, the Blue Ridge, Piedmont and shallow wells in the Coastal Plain have a high risk for corrosive water and lead contamination in their water.

Civil and Environment Engineering Department at Virginia Tech and the Environmental Health Services Branch of the Macon County Public Health Department and lead by Kelsey J. Pieper PhD USDA-NIFA Postdoctoral Fellow at Virginia Tech investigated lead in well water concentrations at the homes of 15 private wells in Macon County found to have elevated levels of lead in their wellhead samples. There was another part of the research but we will not discuss that here.

 Low pH water can corrode metal plumbing fixtures causing lead and copper to leach into the water and causing pitting and leaks in the plumbing system. The presence of lead in pipes and fixtures becomes a bigger problem with water with a pH less than 6. In the past lead was used to solder copper pipes together before 1988 when the 1986 ban on lead in paint and solder went into effect. Also, until 2014 when the 2011 Reduction of Lead in Drinking Water Act went into effect, almost all drinking water fixtures were made from brass containing up to 8% lead, even if they carried a plated veneer of chrome, nickel or brushed aluminum and were sold as "lead free." So even home built with PVC piping in the 2000's may have some lead in most of the faucets.

The pattern of lead release and remediation for lead contamination originating from plumbing have been extensively studied. The goal for the Virginia Tech and the Macon County Public Health Department study was to identify patterns of lead leaching/ release within the well itself. Plumbing components used within a private well are not subject to the 1986 Lead Ban or the 2011 Reduction of Lead in Drinking water Act requirements. Galvanized iron is still commonly used for well casings and fittings and drop pipes in well deeper than 600 feet. Before 2014 Prime Western grade “lead free” galvanized steel zinc coating was required to contain between 0.5%-1.4% lead. After 2014, “lead free” galvanized steel have less than 0.25% lead in the surface coatings. Nonetheless, under corrosive conditions, any lead used in coatings can be easily released to the water and pumped to the household tap or accumulate in scale layers on the pipe surface or well bottom where scale can accumulate and be released or picked up and pumped with the water.

Water lead concentration patterns and sources of contamination within the wells differed among the 15 private wells as can be seen in the diagrams below which come from Environmental Science and Technology article cited below. The scientists found that elevated lead was associated with three sources of lead release: (1) dissolution of lead from well plumbing during periods of stagnation; (2) scouring of leaded scales and sediments along the well plumbing infrastructure during initial water use; and (3) mobilization of leaded scales during continued water use.

From Pieper et al.

As you can see, water lead levels measured during well testing show that in (A) nine wells had no water lead during continued water use however, (B) six wells showed sporadic spikes in particulate lead during continued water use. The detection limit of lead in the analysis was 1 μg/L. Lead contamination in a well can come from three potential sources; galvanized iron well casings, galvanized iron and brass well components, and leaded scales and sediment which have formed over time.

Corrosive water is the primary risk for lead in well water. However, over time water with a neutral pH could dissolve the coating on galvanized iron and in brass well components. The well completion reports do not document materials used for well components in Virginia or anywhere else to my knowledge. Once installed a well casing cannot be removed. It is possible to line the casing with a plastic pipe a technique used to seal a well where the grouting has failed. All the other components of the well can be replaced, though excavation would be required to replace the exterior portions of the pitless adaptor. However, scale that has accumulated on the bottom of the well might remain a source of lead if it is not mechanically removed. Further research needs to be done to further characterize the lead in well and effective remediation techniques.

To read the complete article:

Elevated Lead in Water of Private Wells Poses Health Risks: Case Study in Macon County, North Carolina

Kelsey J. Pieper, Victoria E. Nystrom, Jeffrey Parks, Kyle Jennings, Harold Faircloth, Jane B. Morgan, Jim Bruckner, and Marc A. Edwards Environmental Science & Technology 2018 52 (7), 4350-4357 DOI: 10.1021/acs.est.7b05812