Demand Management of Oil Will be a Persistent Problem after Peak Production

An eventual peak in oil production is viewed by many to be the unavoidable consequence of the consumption of a resource that is by its very nature nonrenewable. Debate continues as to when this peak will eventually be reached, and it depends largely on our ability to sustain oil production through new methods of exploiting unconventional sources of fossil fuel. Hughes and Rudolph (2010) point out that avoiding a peak depends largely on oil fields that have yet to be discovered, and that unconventional oil sources are costly not only in terms of their energy return on energy invested (EROEI<!–[if supportFields]> XE “Energy Return On Energy Invested (EROEI)” <![endif]–><!–[if supportFields]><![endif]–>), but also with regards to the amount of carbon dioxide expelled in their extraction. When an eventual peak is reached, jurisdictions will primarily be limited to three different methods of coping: reduction of demand for energy, replacement of oil with other sources of secure liquid fuel, and restriction of new demand for energy to sources not based on fossil fuel. The authors conclude that the third option seems more likely, but that problems such as finding clean sources of electricity generation and the difficulty of obtaining natural gas in gas-poor regions would still present significant hurdles to our transition away from oil. —Steven Erickson
Hughes, L., Rudolph, J., 2010. Future world oil production: Growth, plateau, or peak? Current Opinions in Environmental Sustainability special issue Energy Systems.

Hughes and Rudolph (2010) analyzed production and demand growth, sources, alternatives, and production outlooks for oil to reach an opinion on the likelihood of an oil peak. They then proceed to offer possible policy reactions to this peak if it were to occur on a timeline similar to that presented by the International Energy Agency (IEA). They conclude that if a peak due to resource exhaustion were to occur, it would be extremely taxing upon the world’s economies, and the resulting problems would not be overcome in a simple and timely manner.
          Hughes and Rudolph begin by emphasizing the importance of oil in today’s world. They state that oil represents 34% of the world’s total energy demand, with coal<!–[if supportFields]> XE “coal” <![endif]–><!–[if supportFields]><![endif]–> and natural gas making up another 47.4% of aggregate energy demand. This was made possible by the exponential and unprecedented growth of oil production. From the dawn of the 20thcentury all the way through the 1970’s, oil production doubled about once every ten years. Following the oil shocks of 1975 and 1980 growth in oil production has continued, though in a less dramatic linear fashion.
          The authors go on to analyze the sources of this oil production. They say that about 85% of oil is produced from conventional sources, for example onshore reserves and those situated in shallow water. However, these sources have largely been in decline, forcing oil companies to resort to more energy intensive unconventional sources, such as the oil sands of Canada<!–[if supportFields]> XE “Canada” <![endif]–><!–[if supportFields]><![endif]–> or the heavy oil of Venezuela, as well as substitutable liquid fuels such as liquefied coal<!–[if supportFields]> XE “coal” <![endif]–><!–[if supportFields]><![endif]–> and natural gas and fuels created from biomass.
          The main difference pointed out between these two sources is not their ultimate product, but rather the amount of energy required to obtain the fuel. In the beginning of the 20th century it has been estimated that oil reserves in the US had an EROEI<!–[if supportFields]> XE “Energy Return On Energy Invested (EROEI)” <![endif]–><!–[if supportFields]><![endif]–> of nearly 100, while the estimated EROEI of newer conventional crude oil wells is closer to 11, with biofuels currently yielding an EROEI somewhere between 1.0 and 3.2. The authors conclude that if increasing demand for oil is to be met, it will be both expensive and environmentally harmful.
          Hughes and Rudolph move on to address the theory of peak oil. Although peak oil has been criticized for its missed predictions in the past, the authors remind the reader that methods of predicting oil production have been improving and such predictions should not be taken lightly. They examine the production outlooks provided by the IEA, which show an increase in liquid fuel production through 2030. However, the authors point out that this depends largely on crude oil that has yet to be found as well as a growing reliance on liquid natural gas. If either of these prospects do not pan out, a peak or plateau in oil production would likely be reached between 2020 and 2030.
          The authors do state that although the IEA’s study is rigorous, there is a shortage of data regarding oil reserves in the Middle East, as much of these data are unavailable to the public. It is unclear whether this would make IEA under or overestimate the total amount of remaining reserves.
          If a peak occurs, meeting future demand for oil would be an unprecedented challenge to world governments and economies. The authors explain that accommodating such a large change would require long-term planning that would likely require a decrease in energy consumption. Strategies to meet the peak would fall under three main labels: reduction, replacement, and restriction. Reduction would involve lowering energy use through conservation and efficiency, replacement would require replacing oil with other liquid fuels, and restriction would limit new energy demand to non-oil sources.
          Hughes and Rudolph conclude that restriction will be the most likely strategy, and that for at least the near term energy usage would likely be restricted to natural gas and electricity. This of course presents its own unique problems. Providing natural gas to gas poor regions like Europe<!–[if supportFields]> XE “Europe” <![endif]–><!–[if supportFields]><![endif]–> would require either new pipelines or the large-scale liquefying of gas. Either of these solutions would subject places like Europe to intense political pressure from suppliers of natural gas. The major problem with electricity on the other hand is the steady supply of environmentally sustainable energy. Countries like the United States and China<!–[if supportFields]> XE “China” <![endif]–><!–[if supportFields]><![endif]–> have already shown a willingness to rely on their massive coal<!–[if supportFields]>XE “coal” <![endif]–><!–[if supportFields]><![endif]–> reserves, which is not environmentally desirable. The authors state that perhaps the best options are renewables such as solar and wind, despite the fact that they would require a change in energy consumption attitudes, from one where usage determines output to output determining usage.

Regardless of Its Veracity, The Theory of Abiotic Oil Formation Does Not Negate The Peak Oil Hypothesis

Throughout history mankind has produced many theories to explain the origin of oil; Aristotle, for example, believed that petroleum was “the result of exhalations from the deep earth.” By the mid 18th century theories of biotic oil formation—that oil and coal<!–[if supportFields]> XE “coal” <![endif]–><!–[if supportFields]><![endif]–> originate from biological remnants subjected to the heat and pressure of the earth—were already entering the mainstream. These biotic theories remain the most prevalent today, and have proved the most successful in predicting locations of large oil reserves. However, in the 1950’s, theories of an abiotic origin of oil, first proposed in the early decades of that century, were revived in Russia<!–[if supportFields]> XE “Russia” <![endif]–><!–[if supportFields]><![endif]–>. Recently, proponents of this theory have stated that deep in the Earth’s mantle there lie vast oceans of oil that make preparations for a peak in oil production a waste of effort. However, Höök et al. (2010b) state that regardless of the viability of the abiotic oil<!–[if supportFields]> XE “abiotic oil” <![endif]–><!–[if supportFields]><![endif]–> formation theory, such reserves would at most only delay the onset of peak oil, as a resource is still considered finite as long as extraction is more rapid than renewal. Therefore, unless abiotic processes create oil on the order of several hundred thousand barrels a day, they will not be able to help us stave off a peak in oil production. —Steven Erickson
Höök, M., Bardi, U., Feng, L., Pang, X., 2010b. Development of oil formation theories and their importance for peak oil. Marine and Petroleum Geology 27, 1995–2004.

          Höök et al. surveyed and summarized the research on the origins of both biotic and abiotic oil<!–[if supportFields]> XE “abiotic oil” <![endif]–><!–[if supportFields]><![endif]–> formation theories and the empirical evidence present for both. After analyzing these data, they reexamine the argument for peak oil taking into account potential reserves created by abiotic oil formation, concluding that unless the “strong” theory of abiotic oil production is true—that is that abiotic oil processes create large quantities of oil over short periods of time—then peak oil will at the very most delay the onset of this production peak.
          Much evidence has been provided to show that hydrocarbons are the result of biotic processes. Chemical analysis has shown a link between chlorophyll in living plants and porphyrin pigments—a type of nitrogen<!–[if supportFields]> XE “nitrogen” <![endif]–><!–[if supportFields]><![endif]–> found in fossil fuel reserves—which originate primarily from chlorophylls. Carbon isotopes<!–[if supportFields]> XE “isotope” <![endif]–><!–[if supportFields]><![endif]–> found in hydrocarbons have also been shown through mass spectroscopy to be the same isotopes favored by living organisms, and oil has also been shown to contain many biomarkers and chemical fossils. Furthermore, biodegradation caused by microorganisms has been shown to result in petroleum being transformed into heavy oil. Höök et al. explain that these theories on degradation could explain all petroleum formation.
          The theory of abiotic oil<!–[if supportFields]> XE “abiotic oil” <![endif]–><!–[if supportFields]><![endif]–> generation, supported primarily by chemists with little geological experience, relies primarily on experimental work that suggests that under high pressures and heat, hydrogen and carbon combine to create hydrocarbon chains. However, drillings in Sweden<!–[if supportFields]> XE “Sweden” <![endif]–><!–[if supportFields]><![endif]–> in the 1980s, which thus far have been the most serious attempt at proving abiotic oil formation, failed to find any recoverable amount of oil.
Some scientists propose that the fact that some oil reservoirs exist in rock formations not traditionally associated with oil is proof that abiotic oil<!–[if supportFields]> XE “abiotic oil” <![endif]–><!–[if supportFields]><![endif]–> generation does exist, however geological studies show that these reservoirs were created by migration of oil from sedimentary source rock nearby through commonly understood mechanisms. Another argument proposed by abiotic oil supporters is that these abiotic oil reserves are at great and largely unexplored depths, but to this date very little oil has been found at depths greater than 5000 m. Furthermore, studies show that oil generally converts into natural gas at temperatures greater than 200 °C, temperatures that generally exist below 5000 m. Höök et al. conclude from their review that although it is possible to create abiotic oil in the laboratory, there has thus far been no evidence suggesting any sort of commercially viable accumulation of abiotic oil in the earth’s mantle.
Höök et al. close their paper by addressing what effect, if any, abiotic oil<!–[if supportFields]> XE “abiotic oil” <![endif]–><!–[if supportFields]><![endif]–> formation would have on peak oil. Their main point revolves around the idea of what it means for a resource to be finite. The authors state that a resource is renewable if and only if its rate of replenishment is greater than its rate of depletion. They use the production of whale oil in the 19th century to illustrate this point. Although whales are able to reproduce, the resource was still finite as whales were killed much more quickly than they could reproduce, causing a very clear peak in whale oil production. They then go on to divide abiotic oil generation theories into two main groups, a weak theory and a strong theory. The weak theory states that oil forms abiotically at rates similar to those assumed in conventional biogenic theories, while the strong theory states that oil reservoirs are replaced more quickly than we deplete them. This rate of replacement would be about five orders of magnitude greater than what is known in conventional oil formation theory.
If the weak theory holds true, then it makes little difference whether or not oil is generated biotically or a abiotically, as we are still consuming petroleum at a rate faster than it is being replaced, and a peak in oil production is inevitable. If the strong theory were true, then a production peak could potentially be put off indefinitely. Unfortunately, the authors state that even the most optimistic supporter of abiotic oil<!–[if supportFields]> XE “abiotic oil” <![endif]–><!–[if supportFields]><![endif]–> has no ability to prove such claims. Therefore, even if abiotic oil generation is real and has created large reserves deep in the Earth’s mantle, its effect on the arrival of peak oil production would ultimately be minimal.

Estimates of Peak Oil Muddled by In-complete Data, Differences in Termi-nology and Varying Theoretical Views

          A peak in oil production due to resource exhaustion is a familiar topic to most. However, as of now no consensus has been reached as to likelihood of whether or not we will encounter this peak in the short run, and if we will, when will it occur. Although there are many reasons why divisions of opinion would occur, among them varying levels of optimism and fields of study, Sorrell et al. review current peak oil research done by the UK Energy Research Centre (UKERC) to explain that some of the main drivers of the uncertainty surrounding peak oil estimates are that the data are sparse and often privately owned, scientists use different and changing terminology, and the assumptions underlying models of oil production and consumption are not necessarily the same. Taking this information into account, the authors then go on to predict that oil production will probably reach a bumpy plateau and then decline rather than a form a true peak. —Steven Erickson
Sorrell, S., Speirs, J., Bentley, R., Brandt, A., Miller, R., 2010. Global oil depletion: A review of the evidence. Energy Policy 38,  5290–5295
          Sorrell et al. summarize the UK Energy Research Centre’s (UKERC) findings in their independent review of the evidence for a peak in oil production. They go on to analyze the various factors influencing the difficulty in both predicting peaks in oil production and getting these predictions taken seriously in the scientific community. They conclude by explaining what needs to be done to the models to make them more reliable as well as giving their opinions on current estimates of future oil production.
          One of the first problems examined is the ambiguity and quality of data. First of all, publicly available data are scant and therefore not very useful. Commercial sources are better, but are also expensive and sometimes impossible to obtain. Further augmenting the problem is the division of reserves into proved (1P) and proved and probable (2P). Neither of these terms has an especially standardized meaning, and because of the lack of data availability scientists must make assumptions in order to get any sort of estimate.
          The process of estimating resource size is also fraught with uncertainty. Geological models are often used for relatively unexplored regions and economic models are typically used to plot out production in areas that are well explored. According to the authors, neither of these techniques take their weaknesses fully into account. They surmise that most techniques will be pessimistic in their estimates. In order to improve the situation, Sorrell et al. (2010) suggest new models that use both historical and geologic data along with economic and political data, but they may provide very different results from previous models for estimating regional recoverable resources.
          Estimating actual oil supply is just as difficult. Both curve fitting and econometric models are used to try to map out supply, but fitted lines lack theoretical basis, and econometrics may not do a better job of predicting future output. The authors state that the ideal model would be one based from the bottom up using project data, but most companies closely guard their data, making that information difficult to attain. The authors assert that although such supply models for a given level of available resources can estimate a peak to within a decade, they can not provide much precision beyond that.
          Sorrell et al. conclude the paper by discussing the timing of the peak. They say that current estimates of URR made by the US Geological Survey (USGS) are around 3345 GB. This estimate puts a global resource peak at around 2030. The authors conclude that if one wants to justify that an oil peak can be put off beyond this date they must rely on some tenuous conclusions, including low demand growth, a reversal in the 40 year trend of declining oil discoveries, and a cumulative production at the date of any potential peak that exceeds 50% of the global URR.

The World After Peak Oil If No Satisfactory Energy Substitute is Found

It is difficult to predict what sort of world we will face if a peak in oil production is caused not by the eventual phasing out of oil but by an exhaustion of supply. This is even more true if technological optimists’ prediction of the creation of a substitute for oil as our main industrial energy resource proves false.  Friedrichs (2010) offers several possible scenarios for this post oil world based on three different historical cases. Countries may resort to military predation as Japan did before and during World War 2, undergo totalitarian retrenchment similar to what occurred in North Korea during the 1990s, or they may rely on improvisation and community in order to adapt to the lack of key resources in a manner similar to Cubans after the fall of the Soviet Union. He goes on to explain that the response would vary depending on historical and political factors in a given country. Friedrichs also offers the example of the failure of the post Civil War South to adapt in a timely fashion to the loss of a key economic resource—slaves—as justification for his views that the world would likely have a very difficult time replacing oil with a new resource after a production peak. —Steven Erickson
Friedrichs, J., 2010. Global energy crunch: how different parts of the world would react to a peak oil scenario. Energy Policy 38, 4562–4569.

          Friedrichs used three historical case studies of countries facing acute oil shortages to extrapolate what the world could look like if oil production reaches a peak and no reasonable substitute is found.  From these studies he derives four hypotheses: “The greater a country’s military potential and the perception that force will be more effective than the free market to protect access to vital resources, the more likely there will be a strategy of military predation,” the less democratic and pluralist a country, the more likely those in power will institute totalitarian retrenchment, the less individualistic a country, the more likely there will be an “adaptive regression to community based values” and finally that peak oil will create winners and loses, that power will shift from oil importers to the exporters, as well as from private oil companies to public ones. Finally, using the post-war American South as a basis, Friedrichs posits that the transition from oil will not be smooth, and that the adaptation may take more than a century.
          The first of Friedrichs’ hypothesis is reached following his analysis of Imperial Japan’s behavior before and during the War in the Pacific. After concluding that Germany’s defeat in World War 1 was due largely to its inability to secure a large enough resource base the leaders of Japan decided that in order to ensure Japanese success they would have to directly control the resources they would need. In the face of trade embargoes on oil, Japan invaded Manchuria, South East Asia, and many Pacific islands. Using this as his basis, Friedrichs surmises that countries with the ability to project their power, particularly the United States and to a lesser extent China, will resort to military predation in order to secure oil after the markets are no longer deemed a convenient or reliable way to meet energy needs.
          Friedrichs’ second hypothesis, that countries with a weak democratic tradition and histories rife with dictatorship will experience a retrenchment of totalitarianism, comes from the events in North Korea following the collapse of the Soviet Union. After the Soviet Union dissolved North Korea no longer received oil in return for political corruption. This led to a complete collapse of the countries economy, including its highly industrialized agricultural sector, leading to widespread famine that killed between 3–5% of the population. At the same time, the elite ruling class continued to enjoy the privileges that they had grown accustomed to while oil was still prevalent. Friedrichs believes that countries in Eastern Europe, Southeast Asia and Africa with their totalitarian pasts will be particularly susceptible to this retrenchment.
          In contrast, Cuba scraped by reasonably well after oil shipments from the USSR ceased in the early nineties. This experience is the basis of Friedrichs’ third hypothesis, that countries with a strong sense of community and are not accustomed to the consumption levels of the industrialized West will be able to subsist through wide-scale socioeconomic adaptation. Due to Cuba’s tight knit neighborhoods and knowledge of traditional agriculture Cubans were able to live at a subsistence level through Urban agriculture that ranged from gardens on the roof to chickens in apartments. Though living without cheap oil certainly made daily life unpleasant, Cuba did not experience any of the widespread famine suffered by average North Koreans. Friedrichs writes that countries that still rely largely on subsistence agriculture in Sub-Saharan Africa and Latin American countries with societies still based around the family and community as opposed to the individual will be the ones most able to make these adaptations.
          Finally, Friedrichs warns that optimism in regards to oil being superseded by new fuels may be unwarranted. He points out that the American South took nearly a century to achieve a quality of life similar to that of the North after its economy lost its key resource, namely slaves. Even though a guide to what should be done existed in the northern states, the South still failed to make adaptations necessary to life post-slavery because of their attachment to the old ways of doing things. Friedrichs concludes that losing oil in the 21st century will have a similar effect on our economy as the emancipation of the slaves had on the American South, and that we have no convenient models to lead us away from the scenarios presented in Friedrichs paper.

Predictions of an Imminent Exhaustion of Oil Resources Based Solely on Fallacy

Following the recent rise in oil prices, the term peak oil has become a popular buzzword. Although the term peak oil can refer to peak in oil production regardless of cause, it is most commonly understood as a peak in resulting from the draining of oil reserves. Predictions on the potential timing of such a peak vary, but some sources predict that the earth could reach peak oil within the next decade or so. However, Radetzki (2010) warns that predictions of an imminent peak in oil production should not be taken seriously, as the major arguments made for this coming peak by groups like the Association for the Study of Peak Oil (ASPO) are largely fallacious with little scientific or economic support. Radetzki goes on to state that a peak in oil production is conceivable, but it would be caused by political or market forces, not a decrease in availability. —Steven Erickson
Radetzki, M., 2010. Peak oil and other threatening peaks—chimeras without substance. Energy Policy 38, 6566–6569.

          Radetzki scrutinized several of the main arguments made by the ASPO in regards to a supposed coming peak in oil production. These arguments include the fixed and limited nature of base oil reserves, that a peak in oil production would occur when half of the ultimately recoverable resources (URRs) are exploited, and that oil discoveries are declining and insufficient to meet the unending increase in demand. Radetzki works to discredit each of these arguments, claiming that they are only “chimeras”.
          Radetzki’s first addresses the assertion that oil will peak when half of the URR has been consumed. She states that although oil fields do reach peak production when about half of the exploitable oil is used up, but there is no convincing reason that this should hold true for global oil production. She goes on to explain that even if this were the case, we lack the ability to ascertain when this halfway point has been reached, as even “resource pessimist” Colin Cambell, a leading player in the Peak Oil Movement, has added 300 billion barrels to his estimates from the URR. Radetzki states that due to the steady advance of technology, the URR is not a simple sum of total resources that can be easily burned through, but rather a result of fluid processes which result in its continual expansion. This holds especially true with oil prices over $60 per barrel, as this makes many novel methods of oil extraction more plausible.
          Radetzki goes on to consider problems raised concerning the slowdown in oil discovery in recent decades. Radetzki explains that the ASPO’s data on the diminishing size of new discoveries is underestimating the total amount of oil being found. This is largely because they ignore an important concept called appreciation. The amount of oil first estimated in a new field is normally about six times smaller than actual reserves due to continuing development of the field and improvement in recovery technology. In the ASPO’s comparisons they use the figures from the fully appreciated oil discoveries in the 60’s and the 70’s, but use the preliminary estimates for newer discoveries, ignoring any appreciation that might occur. It is in this way that, although the quantity and size of new discoveries appears to have slowed, we still see increases in the base reserves.
          Radetzki concludes that although peak oil is a possibility, it will not be due to limited resources. Instead, the economics of energy may change, making newer methods of energy generations preferable to the burning of fossil fuels. If this occurs then demand will naturally fall and production of oil will peter out. Another threat to oil production is resource nationalism—the majority of exploitable oil is controlled by governments—which would effectively cut off certain countries from the natural wealth of resource rich countries. This would indeed cause a production crisis in effected countries, and according to Radetzki is much more likely than an exhaustion of our useable reserves.

Activated Sludge Process with a Fixed Biological Media a Viable Way to Treat Coal Gasification Wastewater.

Coal gasification is often seen as a key to future energy production. It takes advantage of plentiful coal supplies, particularly in the United States and China, in order to create liquid fuels, as well as to produce the hydrogen gas used in the hydrogen fuel cells that many predict will eventually come to power most of our transportation infrastructure. Unfortunately, the process of coal gasification creates wastewater containing many pollutants harmful to the environment, including ammonia (NH4-n), cyclooctadiene (COD), and phenol. Because of this, the continuing and future viability of coal gasification requires effective processes to purify the wastewater that its creation and refinement produces. Traditionally an activated sludge process (ASP) is used to treat this wastewater. Han et al. (2010) found that if a soft fixed biological medium is added into the treatment tanks about 80% of pollutants can be removed in a manner more stable than traditional ASP treatment. —Steven Erickson

Han, H., Li, H., Du, M., Wang, W., 2010. Treatment of coal gasification wastewater by full scale activated sludge process with fixed media. Bioinformatics and Biomedical Engineering (iCBBE), 2010 4th International Conference on, 1–4

        Han et al. studied the effects of submerged biofilm on the ASP. Traditionally ASP does a good job in removing phenol and COD, but has a relatively small effect on NH4-n in the system. The biofilm added contained nitrifying bacteria to breakdown the NH4-n in the wastewater.
       The ASP uses a two stage process, with each stage composed of one large tank and one sedimentation tank, with a total volume per stage of 7000 m3 . The effluent from the coal gasification is mixed with residential wastewater and then flows through the first tank and moves on to the tanks of the second stage in a process that takes about 42 hours. Each stage works through the same method, with the sludge adsorbing and biodegrading the phenol and COD’s, and the bacteria on the biofilm nitrifying the NH4-n. The research team measured the levels of COD, NH4-n and phenol in the wastewater before it entered the system, after the first stage, and upon its exit of the system. These measurements continued over the course of an entire year.
       The results of the experiment were very promising, generating only a few problematic points in the data. COD removal rates after the two stages averaged out to be around 80%. The concentration of COD ranged from 550 to 1760 mg/L in the untreated wastewater, with concentration rates dropping to about 200 mg/L after completing the second stage.
       Similarly, phenol rates were greatly reduced following the ASP. The influent total phenol concentrations ranged from 95 to 345 mg/L, and the effluent total concentrations were around 25 mg/L. The average total rate of phenol removal was 90%.
       The study points out one main drop in filtration capacity by the first stage of the ADP in the 5 weeks between weeks 35 and 40. Normally the first stage of the process filters out 70% of COD and 80% of phenol, but during this period that rate dropped to 60% for both pollutants. Han et al. suggest that the problem might lie in the process by which the sludge removes these compounds. They state that it is possible that the sludge became saturated with pollutants through adsorption and that the process of biodegradation did not work quickly enough to break down the compounds, allowing unadsorbed contaminants to continue on to the second stage. This did not affect the concentration levels after the second stage, which was able to make up for the deficiency in the first stage tanks.
       The rate of removal of NH­4-n from the wastewater began fairly low, but ultimately reached 80% after 15 weeks. The influent NH4-n concentrations ranged from 60 to 110 mg/L, and after 15 weeks the concentration in the effluent was down to around 15 mg/L. Thanks to the biofilm inserted into the tanks, nitrifying bacteria were able to adhere onto them and grow successfully. This was not possible during the traditional ASP process, but the bacteria took time to multiply, leading to the low rates of nitrogen filtration and the beginning of the experiment.
       The first stage of the ADP had problems removing NH4-n even after the 15 week period in which removal rates finally rose to 80%. The authors hypothesize that this was due to a competitive mechanism in which heterotrophic bacteria were preying upon the nitrifying bacteria. This was particularly a problem in the first stage, in which the wastewater still had a high concentration of organic matter due to mixing of the coal gasification wastewater with sewage from the surrounding residential area. Predation was not a problem in the second stage, as concentration of organic matter was much lower.
       Given these results, Han et al.  conclude that ADP with a soft biological medium inserted could remove most NH4-n and organic pollutants from coal gasification wastewater. Additionally, they concluded that this process was more stable than traditional ADP.

The Special Report on Emission Scenarios Overestimates the Quantity of Future Recoverable Fossil Fuels

The Special Report on Emission Scenarios (SRES), compiled in 2000 by the Intergovernmental Panel on Climate Change (IPCC), is a collection of forty possible global emission outcomes over the next 100 years that have served as a basis for many projections on global climate change. Unfortunately many of these scenarios have missed the mark and are no longer entirely plausible. Höök et al. have reviewed the data and have concluded that due to an over-reliance on outdated works as well as a certain unnecessary optimism with regards to mankind’s technological progression, the SRES greatly overestimates the amount of recoverable fossil fuels that will be available to humanity through the year 2100. This has ramifications not only for the overall economic outlooks projected by the SRES, but also for the report’s estimates of total greenhouse gas output, as the burning of fossil fuels accounts for about 57% of anthropogenic greenhouse gas in the atmosphere. Therefore, the SRES needs to revise downwards its estimates of total CO2 in the atmosphere for all of its scenarios to compensate for its overstatement of available resources.¾Steven Erickson

Höök, M., Sivertsson, A., Aleklett, K., 2010. Validity of the fossil fuel production outlooks in the IPCC emission scenarios. Natural Resources Research, 63–81

 Höök et al. reviewed not only the projections for fossil fuel production provided by each of the 40 SRES emissions scenarios and the assumptions made and research used in reaching these projections, but also the relevant literature and statistics that have been published since the SRES’s 2000 publication. After this review they concluded that the IPCC had been overly optimistic about the amount of fossil fuels that could be viably extracted within the next century, and had therefore overestimated the amount of CO2 emissions possible during that time period. Many of the scenarios seem to project the recovery of more fossil fuels than are currently thought to exist, place too much weight on the quantity and feasibility of unconventional fossil fuel reserves, and put unreasonably large demands on the growth of fossil fuel production capacity of several hydrocarbon rich countries.
          The authors believe that these errors stem from the SRES taking an optimistic view of future oil production supported by Rogner (1997) and Gregory and Rogner (1998) and economists Adelman and Lynch (1997). These sources essentially took the viewpoint that we should not look at oil reserves as a fixed quantity, but rather a fluid amount linked directly to our technical knowledge, with the implication that as our technology progresses, our ability not only to use fossil fuels more efficiently, but also to extract unconventional fossil fuels such as coal-bed methane or oil contained in oil shale which were once not viable, will allow us to extend our production of fossil fuels almost indefinitely.
Höök et al., on the other hand, identify various studies that show that the depletion of fossil fuel reserves increases costs enough to offset any gains from new technology, a fact that the SRES seems to ignore.
          They also identify studies that show that the worldwide production of unconventional oil would be required to attain a growth rate of 10% per year for the next 20 years (de Castro et al., 2009) in order to meet SRES projections, which according to Höök and others in 2009 is a feat that has never been attained by any energy system in history.
          Finally, the authors point out that even the quantity and  economic viability of unconventional fossil fuels may be in question. The SRES uses scant detail to assume that coal-to-liquid technology, supposedly a key player in the sustained usage of fossil fuels, is much cheaper than current literature would suggest. Moreover, the estimated quantity of gas hydrates, another key unconventional fossil fuel, have recently decreased by three orders of magnitude, from 1018 m3 to 1015 m3, due largely to an increase in geological knowledge. This means that many of the sources used by the SRES have become obsolete and that the conclusions based on those sources are suspect at best.
          The authors purport that all of these factors necessitate numerous revisions downwards in regards to the expected output of fossil fuels, and that already several scenarios contained in the SRES can be ruled out. If the IPCC would like to avoid such exaggerated figures on resource availability in the future the authors suggest that the IPCC would do well to hire more resource experts the next time around.