According to EPA (2016), environmental management involves the development of systems aimed at reducing environmental impacts of various activities. In the Brundtland commission report (WCED), sustainable development has been described as development aimed at meeting the current needs of the present generation. However, as the current generation focuses on meeting their own needs, their activities should not compromise the capability of future generations to also meet their own needs. Available evidence suggests that the future generation would have challenges meeting their own needs if the current generation fails to adopt sustainable practices. The sustainable development incorporates the triple line: social, economic, and environmental development.
The exploration, production, distribution, and use of oil and gas has been found to pose negative environmental consequences on the environment. This environmental consequences can occur in the form of air, soil, and water pollution. Pollution reduces the quality of air, water, and soil and thereby threaten plant, animal, and human survival. The following is a discussion of environmental impacts resulting from oil and gas exploration, production, and distribution as highlighted in TEEI (2016).
Oil and gas exploration involves activities such as seismic surveys, exploratory drilling, and testing. These activities are temporary and are usually conducted on a relatively smaller scale than those involved during development/drilling, production, and decommissioning.
Air pollution occurs in the form of noise and is associated with seismic surveys, vehicle traffic, blasting, drill rig operations, and earth-moving equipment. Pollution can also occur in the form of reduced air quality due to dust and emissions from vehicles, earth-moving equipment, well completion, seismic surveys, drill rig exhaust, and testing. Major pollutants, in this case, include oxides of nitrogen, volatile organic compounds (VOCs), particulate matter, sulfur dioxide, and carbon dioxide.
Hazardous materials dumped at the exploration sites which can lead to soil pollution include containers, plastics, fuel spills/leaks, food, paper, and human waste. During exploratory drilling pollutants include filters, mud, drilling fluid, used oil, spent and unused solvents, solid waste, drill cuttings, garbage, and spilled fuel. Exploration activities such as the action of traffic result in enhanced soil erosion.
When exploration activities are carried out in water bodies such as lakes, oceans, and seas, certain activities lead to water pollution. Some of these activities include oil spills and solid wastes left by the exploration crew.
During drilling/development, activities which may result in environmental impacts include ground clearing, drilling, pedestrian and vehicular traffic, grading, construction and installation of structures and facilities, and waste management.
Environmental impact on air includes generation of a lot of noise by drill rigs, bulldozers, vehicular traffic, blasting, and heavy diesel engines. Drilling/development activities also affect air quality. Emissions generated during drilling/development include emissions from vehicles, generators, and large construction equipment. Typical air pollutants include particulates, oxides of nitrogen, and carbon monoxide.
Certain materials released during drilling/development are hazardous and can pollute the soil. This includes solid wastes, hydraulic fluids, used oil, pipe dope, spilled fuel, rig wash, drums and containers, paint and paint washes drill cuttings, sandblast media, garbage, solid waste, and sandblast media. In areas with naturally occurring radioactive materials such as radium-266 and radium-228, the materials pollute the soil. Impacts of soil can also occur in the form of removal of vegetation cover, soil compaction, mixing of horizons of soil, increased susceptibility to both water and wind erosion, loss of productive topsoil, disturbance of soil crust carrying biota, and soil contamination with petroleum products.
Drilling/development activities can result in degradation of the quality of water which can be observed from increased water salinity, turbidity, sedimentation, and spills. Depletion of water quantity and cross-aquifer mixing can occur. Drilling and development activities influence the flow of both ground water and surface water.
Environmental impacts resulting from production activities occurs mainly from a long-term change in habitat within with the oil and/or gas field. Production activities which can result in environmental impact include maintenance and/or replace of facility components, waste management such as produced water, noise from operations, potential spills, and the presence of workers.
Purging gases, flaring, and venting, combustion processes of gas and diesel engines, fugitive gases during loading/unloading, airborne particulates, and particulates from burning sources are an example of air pollution during production (E&P Forum/UNEP, n.d.). A lot of noise pollution is produced at the production site by various activities and processes including production wells, vehicles, and pumping stations. Noise is a major problem for recreationists, wildlife, and the residents. Air quality is also compromised during oil and/or gas production. Emissions are usually generated by on-site storage of oil, operations in pumping stations, well production operations, vehicular traffic, and separation of phases of oil and gas. Most common emissions include nitrogen oxides, volatile organic compounds, sulfur oxides, ethyl benzene, polycyclic aromatic hydrocarbons (PAHs), carbon monoxide, ozone, toluene, methane, xylenes, hydrogen sulfides, particulates, and benzene. Venting of natural gas may take place during well testing, oil production, cavitation, oil and gas processing, pipeline maintenance operations, and well leaks. During development of coal bed methane, compounds such as hydrogen sulfide and carbon dioxide may seep. Methane has been found to be a major greenhouse gas and production of coal bed methane may result in reduced threats posed by climate change. Besides reducing visibility, air pollution taking place during oil and gas production may also cause health effects.
Operation activities taking place during the production of oil and gas results in the generation of hazards materials which can degrade the quality of the soil. Some of the industrial wastes generated include hydraulic fluids, lubricating oils, solvents, coolants, and cleaning agents. Fracking fluids used during production of oil and gas contain hazardous substances such as diesel fuel (containing xylene, ethyl benzene, naphthalene, benzene, toluene, and other chemicals), polycyclic aromatic hydrocarbons (PAHs), formaldehyde, glycol esters, methanol, sodium hydroxide, ethylene glycol, and hydrochloric acid. Sand separated from water produced from production processes is contaminated with soil polluting components such as trace amounts of metals, oil, and naturally occurring elements. Large volumes of sludge wastes and scale accumulate inside storage vessels and pipe. The waste contains produced and, precipitated sulfate and carbonate scales, tight emulsions, heavy hydrocarbons, rust particles, salts, and other metals. In certain occasions, produced water contain traces of naturally occurring radioactive materials like radium-226 and radium-228.
Hydraulic fracturing processes involve the use of some fluids. The fluids usually used has the potential to contaminate water sources especially groundwater reservoirs. For example, stimulation fluids may seep or flow beyond the fracture into the adjacent formation. When stimulation is stopped, and production resumed, some of the stimulation chemicals might not have been completely recovered and transmitted back into the wellbore. If movable, they can easily flow through an aquifer. Most of the water produced during production of oil and gas are not suitable for either domestic or agricultural use because they contain either extremely salty or contains traces of naturally occurring radioactive elements or hazardous compounds. If disposed to the surface without prior treatment, such water has the potential to not only contaminate surface soil but also surface water. Improper completion or maintenance of injection well over time can result in impacts on the aquifer by injected water produced. Other impacts of water quality and availability during the production phase of oil and gas include the possibility of minor degradation of the quality of water as a result of vehicular traffic and operation of machinery during maintenance. This includes sedimentation and erosion. During production, failure of equipment can result in massive contamination of water bodies especially when production is taking place in the seas. Water removal from coal methane has been associated with diminished dry springs, sub irrigated lands, domestic and stock water wells, and streams. Records have shown that removal of shallow aquifers has resulted in subsidence of land to as much as 40 ft. such subsidence causes damage to structures such as roads, utility pipelines, and buildings. Depleted water resources force local water residents to drill deeper in search of adequate water. Disposal of produced water especially those from coal bed methane can contain potential pollutants such as boron, ammonia, arsenic, radium, fluoride, iron, and manganese. Increases in sodium concentrations, salinity, and soluble pollutants occur in streams receiving water discharges from coal bed operations. Underground fires result in by-products such as PAHs, which can lead to the contamination of underground water sources.
Once produced crude oil and/ or gas is transported to the refinery. Various means of transport are employed. These include pipelines, ships, boats, tankers, and trucks. In some situations, more than one type of transport is involved. For example, a pipeline might be used to transport crude oil from the field to the port. From the port, it is offloaded into an oil tanker and shipped to other locations. Offshore pipelines can be running on the surface or buried underground while onshore pipelines run on over the seabed. After refinement, oil and /or gas products can be transported by the same means: pipelines, boats, trucks, ships, and tankers.
Air pollution during transportation occurs mainly from transport equipment which is powered by fossil fuels. Carbon dioxide released into the air has been associated with global warming. These include ships, boats, trucks, and tankers. They release oxides of nitrogen, carbon monoxide, and also particulate matter. Leakage of gas such as methane during transit also causes air pollution. There are also a lot of noise pollution caused by trucks and pumps.
Trucks and pipelines transporting crude petroleum or finished products can contribute to pollution of soil when crude oil leaks. During routine maintenance or accidents, leakages in trucks and pipelines lead to soil pollution.
Water pollution takes place when oil leaks from onshore oil pipelines or in ships, boats, and tankers. Surface runoff can also wash off leaked oil from the land surface to water streams which lead to water contamination.
There are new technologies recommended for mitigating of air pollution by gases such as oxides of nitrogen. Mitigation of air pollution in the context of oil and gas exploration/production/distribution have positive environmental, social, and economic benefits.
Emission control for NOx emissions has been efficiently achieved by using selective catalytic reduction (SCR) techniques. SCR I an after-treatment device fitted at the exhausts system of diesel engines. SCR is capable of removing 90% of NOx present in the exhaust. The device has a lot of environmental benefits since it reduces NOx which would have been released and which can pollute the air. The initial cost of SCR is $384,000 with the additional operating cost of $62,000/yr. This translate to an average of $22,000/ton of NOx controlled (CEC, 2005). The device facilitates running of diesel engines in oil exploration/production/distribution thus resulting in positive economic impacts in communities. It also helps reduce the level of NOx emitted and thus help sustain a clean environmental. Clean air enables communities live a healthy life and minimize expenditure in medical care. Exploration/production/distribution of oil and gas results in employment creation which is a positive social impact.
Emissions of Air pollutants in the oil and gas industry is regulated by EPA guidelines (EPA, 2012). One of the rules applies to emissions of toxic gases. Toxic gases have been found to cause cancer and other health complications. The rules were predicted to result in I savings of between $11 million to $19 million by the year 2015. Annual reduction of toxic gases was estimated to be between 12,000 to 20,000 tons per year (EPA, 2012). To ensure the plants adhere to the standards set by EPA, various techniques have been developed and employed to monitor NOx emissions. Implementation of tasks required to reduce emissions rests with the managers who are fully aware of the statutory standards and commitments they made. Monitoring of emissions ensure that commitments to emission reductions are met (E & P forum/UNEP,n.d.). Monitoring NOx, in this case, takes the form of direct measurements and recording of quantitative information, for example, amounts of NOx emitted at any given time against EPA standards. Monitoring systems are available for selective catalytic reduction of NOx (Emerson, 2016). Monitoring can be outsourced to an agent who will make sure there is a continuous monitoring of emissions of NOx. When emissions fail to comply with EPA regulations, the agent reports the problem and action are immediately taken to reduce emissions to the permitted levels.
Activities involved in the exploration, production, and distribution of oil and gas results in negative environmental impacts. Mitigation measures applicable to air, soil, and water will be considered here.
Reducing air quality impacts focus mainly on air releases and fugitive gases. The following are recommended measures:
All access roads and on-site roads should be made from gravel.
For areas cleared of vegetation, minimum disturbance should be maintained.
Emission control devices should be used during drilling operations.
Low sulfur fuels should be specified to reduce emissions
Dust abatement techniques should be used to minimize dust especially in unpaved or areas cleared of vegetation.
Speed limits should to introduced to avoid dust caused by vehicular traffic
Plant vegetation in areas initially it was covered with vegetation as soon as possible
Stockpiled soils and construction materials should be covered if they are sources of dust
Workers ought to be trained on how to handle debris and construction materials and dismantle to help in reducing emission of fugitive dust
Soils should be kept moist when loading onto dump trucks
Soil loads ought to be kept below freeboard of the trucks
Load heights should be minimized during soil dumping
Gate seals for dump trucks ought to be tightened
When traveling on public roads, dump trucks should be covered.
Compressors to be electrically powered. Otherwise, strict rules pertaining air emissions to be put in place.
Reducing soil pollution focus mainly on things which affect soil quality. The following are recommended measures:
Soil erosion to be minimized by constructing features such as drainage ditches to control runoff. Soil erosion control measures to be also applied to reduce soil erosion taking place during vehicular traffic and drilling.
A protective covering or reclamation on disturbed soils should be instituted as soon as possible
Keeping drilling equipment and vehicles within initially disturbed zone
Gravel should be placed in locations susceptible to wind erosion
Avoid creation of steep slopes
Borrow materials should be obtained from authorized sites
Materials excavated should be disposed of in approved areas to minimize cases of leaching of hazardous materials and also to stop soil erosion.
Topsoil produced during drilling equipment should be saved and used to reclaim the site upon completion of site activities and during decommissioning.
Alternative approaches that can be used to reduce impact of activities involved in oil and gas are:
Avoiding slopes which are unstable or any other local factors that can result in slope instability such as presence of ground water
Avoid any likelihood of creating hydrologic conduits between two or more aquifers. This can be avoided by first conducting a local hydrogeology to map out areas with groundwater discharge as well as recharge and their association with groundwater quality and surface water bodies
Focus on minimizing size of disturbed land
Avoiding streams, drainages, and wetlands
Where there are erodible soils, steep slopes, and stream crossings, special construct equipment should be used
The existing drainage system should not be altered.
Erosion control measures should be applied to minimize erosion caused by vehicular traffic
Catch drains, drainage, and culverts should be cleaned and maintained regularly
Refuel should be done in designated area to avoid spread of spillage
Drip pans to be used during refueling to avoid leakage
Use of chemicals like pesticides should be minimized
Construction near aquifer should be monitored to avoid erosion
Banks of water bodies should be returned to their original condition
Reclaim site to near its original contour after decommissioning
Commission for Environmental Cooperation (CEC), 2005. Best Available Technology for Air Pollution Control: Analysis guidance and case studies for North America. [Online]. Available at: http://www3.cec.org/islandora/en/item/2195-best-available-technology-air-pollution-control-en.pdf [accessed 25March 2016]
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World Commission on Environment and Development (WCED), 1987. Our Common Future. Oxford: Oxford University Press.