Bioremediation of Groundwater Contaminated by Hog Manure Nitrates
Groundwater is a major water resource both for drinking water and agriculture. Since the industrial revolution, groundwater quality has been deteriorating and has become a major environmental concern. Dangerous organic chemicals along with heavy metals and nitrogenous pollution have made their way into water that is stored under the ground throughout the world. Many of these chemicals pose risks for human health and are regulated by the Environmental Protection Agency. As drinking water sources become scarcer throughout the world, there is a need to improve groundwater clean up technologies. This case study was set up as a laboratory exercise for environmental studies, it is appropriate that it be used here in this report as a case study for remediation (Cornell, 2003).
Nitrate pollution is a result of agricultural practices such as excessive fertilizer application and improper disposal of manure. Nitrate is regulated by the Environmental Protection Agency with a maximum contaminant level. Toxic levels of nitrate can cause methemoglobinemia (blue baby syndrome) in infants. Blue baby syndrome can cause babies to die from suffocation.
Hog Farm Ithaca is located in Ithaca, NY. They have a major problem dealing with their waste disposal. They have been storing hog manure in treatment lagoons, but they recently discovered that nitrate pollution has leaked into the groundwater. Hog Farm Ithaca is facing fines for violating state and federal regulations.
Groundwater in the vicinity of Hog Farm Ithaca has been sampled and concentrations of nitrate between 100 and 150 ppm NO3-N have been measured. This exceeds the maximum contaminant level (MCL) of 10 ppm NO3-N according to the Environmental Protection Agency (EPA).
Bioremediation of contaminated groundwater is a relatively new technology that uses bacteria to transform pollutants into harmless compounds. The first step an engineer makes when trying to bioremediate a polluted site is to assess if pollution-eating bacteria live at the site and what these bacteria would need to remove the contaminants that are present. This can be done in a laboratory by building microcosms, which can be as simple as jars that contain a sample of contaminated soil and water.
This farm was treated using a bioremediation of groundwater technique using selected microbes. Pseudomonas are bacteria that can degrade nitrate into nitrogen gas (thus removing nitrate from water). For nitrate removal, Pseudomonas require dissolved oxygen levels less than 0.5 ppm, and in addition to that they need a carbon source. Just like humans breathe oxygen and eat various carbon sources, such as sugar, and form carbon dioxide, Pseudomonas can under certain conditions breath nitrate when there is no oxygen present. They were applied to the site. The results were that they consumed and broke down carbon sources such as sugars. During this process they transformed the water nitrate into nitrogen gas, which then left the water in the form of nitrogen bubbles. This harmless gas currently makes up over 70 percent of our current atmosphere.
Many times there is enough organic matter in soil or groundwater to meet the carbon needs of Pseudomonas bacteria to remove the nitrates, but in order to remove large amounts of nitrate, carbon usually must be added. Two inexpensive carbon sources that could be use are vinegar (acetic acid) and/or table sugar (sucrose). It is often best to add both types of carbon sources because we do not know which carbon source Pseudomonas prefer to lead to more effective nitrate removal. Bacteria also require additional nutrients, which will often be required to achieve the best remediation program.
Nitrate pollution is a result of agricultural practices such as excessive fertilizer application and improper disposal of manure. Nitrate is regulated by the Environmental Protection Agency with a maximum contaminant level. Toxic levels of nitrate can cause methemoglobinemia (blue baby syndrome) in infants. Blue baby syndrome can cause babies to die from suffocation.
Hog Farm Ithaca is located in Ithaca, NY. They have a major problem dealing with their waste disposal. They have been storing hog manure in treatment lagoons, but they recently discovered that nitrate pollution has leaked into the groundwater. Hog Farm Ithaca is facing fines for violating state and federal regulations.
Groundwater in the vicinity of Hog Farm Ithaca has been sampled and concentrations of nitrate between 100 and 150 ppm NO3-N have been measured. This exceeds the maximum contaminant level (MCL) of 10 ppm NO3-N according to the Environmental Protection Agency (EPA).
Bioremediation of contaminated groundwater is a relatively new technology that uses bacteria to transform pollutants into harmless compounds. The first step an engineer makes when trying to bioremediate a polluted site is to assess if pollution-eating bacteria live at the site and what these bacteria would need to remove the contaminants that are present. This can be done in a laboratory by building microcosms, which can be as simple as jars that contain a sample of contaminated soil and water.
This farm was treated using a bioremediation of groundwater technique using selected microbes. Pseudomonas are bacteria that can degrade nitrate into nitrogen gas (thus removing nitrate from water). For nitrate removal, Pseudomonas require dissolved oxygen levels less than 0.5 ppm, and in addition to that they need a carbon source. Just like humans breathe oxygen and eat various carbon sources, such as sugar, and form carbon dioxide, Pseudomonas can under certain conditions breath nitrate when there is no oxygen present. They were applied to the site. The results were that they consumed and broke down carbon sources such as sugars. During this process they transformed the water nitrate into nitrogen gas, which then left the water in the form of nitrogen bubbles. This harmless gas currently makes up over 70 percent of our current atmosphere.
Many times there is enough organic matter in soil or groundwater to meet the carbon needs of Pseudomonas bacteria to remove the nitrates, but in order to remove large amounts of nitrate, carbon usually must be added. Two inexpensive carbon sources that could be use are vinegar (acetic acid) and/or table sugar (sucrose). It is often best to add both types of carbon sources because we do not know which carbon source Pseudomonas prefer to lead to more effective nitrate removal. Bacteria also require additional nutrients, which will often be required to achieve the best remediation program.