Onshore oil and gas activities which discharge waste water can potentially contaminate groundwater. According to a book entitled ‘Overexploitation and Contamination of Shared Groundwater Resources’ published by the NATO Science for Peace program, around 70% of the world’s fresh water comes from groundwater aquifers. Egypt is less reliant on groundwater than other parts of the world, representing just 15.3% of the country’s annual water supply, at 11.3 billion cubic meter per year. Nonetheless, any pollutants that enter groundwater reservoirs as a result of oil and gas activities can cause infections for humans and animals, and may even lead to death. Hence, the Egyptian oil and gas industry has begun to employ new methods and new approaches in order to mitigate groundwater contamination.
Egypt has several groundwater sources “ranging from shallow local aquifers [in the Nile Delta], recharged by rainfall, to deep non-replenishable aquifers [in the Western Desert and in Nubian sandstone],” according to research by the Egyptian Journal of Chemistry.
Due to the population growth in Egypt, a lot of people have moved to the new cities built in the wider desert where the main source of fresh water is groundwater. Hence, groundwater “ranks as the second source after the Nile River,” the journal’s article explained.
Around 1.65 billion cubic meters of groundwater is used in Egypt each year, mainly taken from around the Western Desert oases, Walaa Y. Elnashar said in her article ‘Groundwater Management in Egypt’. Yet, groundwater in the desert and in coastal cities has been contaminated for a number of reasons; one of those being the activities of the oil and gas sector.
When oil fields produce, the output is combined with water. Despite extracting oil from this produced water, the wastewater is still not clean as it “will contain some residual oil usually in the form of small droplets dispersed in the water and also possibly some solids,” David Robinson wrote in an article entitled ‘Oil and gas: Water treatment in oil and gas production – does it matter?’
The water will further have “small amounts of dissolved hydrocarbons and gases such as (corrosive) carbon dioxide and the lighter hydrocarbons, as well as any water-soluble chemicals used to optimize the production of the hydrocarbons,” Robinson explained.
“Crude oil is generally composed of a wide range of hydrocarbons and a small amount of impurities, in addition to different types of heavy metals including arsenic, cadmium, mercury and nickel,” according to an article published by the National Authority for Remote Sensing and Space Sciences. Accordingly, discharging this wastewater on the onshore oil fields contaminates the country’s groundwater sources.
Oil and gas operations can also lead to the presence of methane in nearby groundwater aquifers, according to research by the American Geosciences Institution. In addition, groundwater can also become contaminated if oil or other polluting materials are spilled on the surface.
Exploration equipment also risks polluting groundwater as it can be affected by “rig and turbine washes, hydraulic fluids used in oil wells stabilization, rigs and turbines waste oil storage, and chemicals used in the primary treatment of products on field,” Ahmed Abd El Maged Maharek, Senior Environmental Engineer and Water Quality Expert, told Egypt Oil & Gas.
The Dangers of Groundwater Contamination
According to the Groundwater Foundation, groundwater contamination can lead to dangerous health effects, including hepatitis, dysentery, and cancer.
“Contamination of groundwater with heavy metals sources such as chemicals, waste oil and hydraulic fluids with high levels of heavy metals can be a source of poisoning, especially in remote areas where groundwater is a main source for drinking water and daily activities,” Maharek noted.
People who drink groundwater contaminated by heavy metals, which is due to petroleum activities, “risk acute and chronic toxicity, liver, kidney, and intestinal damage, anemia,” according to an article published by the United States Environmental Protection Agency (EPA).
Moreover, groundwater contamination has been linked to some diseases including cholera, according to Arcadia Power’s article ‘Causes and Effects of Groundwater Pollution’. The polluted water can lead to birth defects and harm children. “One example of a serious condition caused by groundwater pollution is the nitrate-induced illness called Methemoglobinemia or ‘Blue Baby Syndrome’. This can affect children whose formula is mixed with nitrate rich water,” the article pointed out.
The extent to which polluted groundwater can be a severe health and environmental hazard was demonstrated in a study conducted in the US. The research revealed that groundwater contamination had led to 403,000 people becoming infected and 80 dying, explained Raafat Abdelrazek, safety department manager at the General Petroleum Company (GPC), during his presentation in Egypt Oil & Gas’s Field Best Practices Workshop held on September 22.
Egypt has started to tap its unconventional resources while exploring for natural gas in the Apollonia reservoir. Hydraulic fracturing “is known for its possible impact on groundwater quality by the introduction of unwanted byproducts, chemical and contaminated oil that cause pollution of the soil and migrate to the groundwater reservoir as a result of discharge or accidental spillage,” Maharek explained.
The process affects groundwater as “an average shale well can use anywhere from 2 to 7 million gallons of water during its lifetime,” Christopher Coats wrote for Forbes.
The Apollonia reservoir is located close to groundwater aquifers. Most of Egypt’s west is part of the 2 million square km of fissured carbonate aquifer called the Nubian sandstone aquifer system (NSAS), according to the article in the Egyptian Journal of Chemistry. The aquifer goes in Egypt, Libya, Chad and Sudan. The aquifer holds around 150,000 cubic km of groundwater, the article said, adding that it is “composed mostly of hard ferruginous sandstone with clay and great shale intercalation”.
A study published by Hydrogeology Journal mentioned that the NSAS has several formations including the Upper Cretaceous layer consisting of the Apollonia, Khoman and Abu Roash formations, and the Dabaa formation.
Tapping natural gas in unconventional resources is processed through hydraulic fracturing. When this process takes place near groundwater sources “there is a greater potential for activities in the hydraulic fracturing water cycle to impact those resources,” according to the US Environmental Protection Agency (EPA).
Groundwater aquifers that are close to hydraulic fracturing operations could be affected by spillage on the ground and pollutants derived from well-bore failures, an article by Proceedings of the National Academy of Science of the United States of America (PNAS) explained.
Coastal cities on the Red Sea have two sources of water: desalinated sea water and groundwater. Ras Ghareb, a city on the Red Sea, is an important site for oil exploration and production activities, and has six large oil fields in the vicinity.
The National Authority for Remote Sensing and Space Sciences conducted a geophysical survey of Ras Ghareb and analyzed the collected groundwater samples. The research found that groundwater contained low levels of total petroleum hydrocarbons (TPH) in the groundwater, and detected low quantities of zinc, chromium, selenium, arsenic, cyanide and mercury. Copper levels were found around the intervention value – the level at which action is required to clean the water – while high levels of lead and cadmium were detected that exceeded the intervention values.
According to the analysis, cadmium traces were highest near the Kareem and Al-Ayun oilfields, while the highest levels of TPH and benzene, toluene, ethylbenzene and xylene (BTEX) were found near wells number 10 and 15, near the Um Yusr station. The research, indicating a severe level of contamination, stated that there was a “necessity for remedial action”.
Mitigating Groundwater Contamination
Preserving groundwater against oil contaminants is vital as Egypt’s per capita water share keeps decreasing over time. CAPMAS data reveals that during the 67 years between 1947 and 2013, Egypt’s annual water quota per citizen decreased by 60%. The trend is set to continue as the population grows, the temperature changes, and as Ethiopia builds a dam that is expected to affect Egypt’s water share.
To protect groundwater, companies should try to control the leakage of contaminating materials. “Oil and chemical spill kits represent a very first defense line to contain and prevent chemicals and oils from reaching the soil,” Maharek said, adding that “using this material became more common in Egyptian fields but needs to be promoted to be fully integrated.”
It is dangerous to discharge wastes in the soil as it pollutes groundwater. Hence, operators could use septic tanks that enable the separation of wastewater into three layers: solid, liquid, oil/grease. Abdelrazek, proposing this method during his presentation at the Field Best Practices workshop, said however that this kind of septic tank can only be used in soil that is “at least semi-permeable and not be saturated around the tank”.
Egypt can also adapt international methods to prevent contamination. Maharek suggests the usage of “soil bioremediation by introducing microorganisms to consume and break down soil pollutants and prevent its migration to the groundwater.” However, he added that “the Egyptian laws don’t have criteria for soil contamination and bioremediation.”
Not only should operators try to control contamination, but employees should also act according to specific standards to protect groundwater. Maharek proposed “raising the awareness of the on-site staff site to manage fuel or lubricant spills properly if they occur,” stressing the importance of “implementing clear and strict environmental management procedures for the hazardous materials handling and storing.”
By using the right techniques, following global environment standards and training people on safety, the companies could mitigate groundwater pollution. As Egypt implements new HSE technologies in E&P activities, the country could control pollution. Eventually it would be able to secure local water demands for people and combat the water shortage problem; meeting the needs of agriculture and other water-dependent economic sectors.