Hannah Arendt’s turn to the self and environmental responses to climate change paralysis

Environmentalists have struggled with how to mobilize people to act in the face of widespread and now inevitable consequences of climate change. Significant responses to this challenge, such as incentivizing individual Green choices in the market and avoiding the rhetoric of catastrophe, continue the philosophical and political trends, identified by Hannah Arendt, that contribute to world alienation and the decline of politics. Environmental thinkers are invited to use Arendt’s theories of the turn to the self and political action to think critically about contemporary strategies to address climate change.     

RESULTS OF ACIDIZING WATER WELLS IN ARIZONA1

Two wellfields have been developed to provide water for a coal fired electric generating station in Arizona. Wellfield No. 1 penetrates the unconfined Coconino Sandstone aquifer, and wellfield No. 2 penetrates the composite Kaibab Limestone-Coconino Sandstone aquifer where ground water occurs under confined conditions. A well in each wellfield was pumped and water level drawdown data were collected before and after acidizing. The drawdown data at the various pumping rates were analyzed to determine the potential benefits of acidizing production water wells in both wellfields. After acidizing, the specific capacity of the well in wellfield No. 1 was improved about 50 percent at water production rates ranging from about 200 to 500 gallons per minute (gpm) (13 to 32 liters per second (lps)). After acidizing, the specific capacity of the well completed in wellfield No. 2 was improved about 100 percent at pumping rates ranging from about 1,250 to 2,200 gpm (79 to 139 lps). An annual saving of approximately 11 percent in pumping costs can be realized in wellfield No. 2, and savings are approximately four percent in wellfield No. 1. Acidization is beneficial for wells that can produce more than 500 gpm (32 lps), and is of marginal value for those that produce less than that amount.     

An assessment of historical change in two northern Minnesota lakes

Two northern Minnesota lakes that had been studied in detail 22 years earlier (1958) were restudied to determine the extent of alteration in ecological conditions. Approximately one year after the original investigation, a coal-fired power plant, which incremented sulfate loading by about 6 kg/ha-yr, began operation nine miles away. These lakes lie within a region judged susceptible to acidic precipitation, though each lake, based on its buffering capacity, would be judged only moderately sensitive. In spite of the influence of this plant and other anthropogenic inputs, the change in lake ecology was apparently minimal. Water clarity decreased in both lakes and some alteration in zooplankton community structure was observed. The long-term utility of lake surveys depends upon how carefully and completely conditions can be reconstructed from records and reports. Past surveys generally omit measures of variability for the data, allowing only qualitative comparisons to be drawn. In order to judge the graded responses of aquatic ecosystems, necessary to sound management, quantitative measures are needed.Deceased.     

Mercury Measurement and Its Control: What We Know,Have Learned,and Need to Further Investigate

ABSTRACT

Based on the available evidence of health effects, the U.S. Environmental Protection Agency (EPA) has been evaluating the need to regulate mercury releases to the environment. In response to the congressional mandates in The 1990 Clean Air Act Amendments (CAAA), the EPA has issued the Mercury Study Report and the Study of Hazardous Air Pollutant Emissions from Electric Utility Steam Generating Units Report. In spite of the enormous effort represented by these reports, as well as the efforts of both the U.S. Department of Energy (DOE) and the Electric Power Research Institute (EPRI), in conducting the field measurement programs that form the basis for these reports, a definitive answer on the need for mercury regulation has not been found. However, the EPA, as well as other regulatory agencies and health researchers, have suggested a “plausible link” between anthropogenic sources emitting mercury and the methylation, bioaccumulation in the food chain, and adverse health effects in humans and wildlife.

Policy-makers have recognized that regulations must be based on good science and that a number of issues still remain. These issues can generally be grouped into four main categories: emissions inventory, control technology, fate of releases, and health effects. This paper will discuss recent, ongoing, and planned studies to address the remaining issues regarding the presence of mercury in the environment, with an emphasis on those studies that are directly related to the DOE/Federal Energy Technology Center’s (FETC) programmatic effort.     

Modeling sorbent injection for mercury control in baghouse filters: I--model development and sensitivity analysis

A two-stage mathematical model for Hg removal using powdered activated carbon injection upstream of a baghouse filter was developed, with the first stage accounting for removal in the ductwork and the second stage accounting for additional removal caused by the retention of carbon particles on the filter. The model shows that removal in the ductwork is minimal, and the additional carbon detention time from the entrapment of the carbon particles in the fabric filter enhances the Hg removal from the gas phase. A sensitivity analysis on the model shows that Hg removal is dependent on the isotherm parameters, the carbon pore radius and tortuosity, the C/Hg ratio, and the carbon particle radius.     

The thief process for mercury removal from flue gas

The Thief Process is a cost-effective variation to activated carbon injection (ACI) for removal of mercury from flue gas. In this scheme, partially combusted coal from the furnace of a pulverized coal power generation plant is extracted by a lance and then re-injected into the ductwork downstream of the air preheater. Recent results on a 500-lb/h pilot-scale combustion facility show similar removals of mercury for both the Thief Process and ACI. The tests conducted to date at laboratory, bench, and pilot-scales demonstrate that the Thief sorbents exhibit capacities for mercury from flue gas streams that are comparable to those exhibited by commercially available activated carbons. A patent for the process was issued in February 2003. The Thief sorbents are cheaper than commercially-available activated carbons; exhibit excellent capacities for mercury; and the overall process holds great potential for reducing the cost of mercury removal from flue gas. The Thief Process was licensed to Mobotec USA, Inc. in May of 2005.     

Mercury Measurement and Its Control: What We Know,Have Learned,and Need to Further Investigate

ABSTRACT

Based on the available evidence of health effects, the U.S. Environmental Protection Agency (EPA) has been evaluating the need to regulate mercury releases to the environment. In response to the congressional mandates in The 1990 Clean Air Act Amendments (CAAA), the EPA has issued the Mercury Study Report and the Study of Hazardous Air Pollutant Emissions from Electric Utility Steam Generating Units Report. In spite of the enormous effort represented by these reports, as well as the efforts of both the U.S. Department of Energy (DOE) and the Electric Power Research Institute (EPRI), in conducting the field measurement programs that form the basis for these reports, a definitive answer on the need for mercury regulation has not been found. However, the EPA, as well as other regulatory agencies and health researchers, have suggested a "plausible link" between anthropogenic sources emitting mercury and the methylation, bioaccumulation in the food chain, and adverse health effects in humans and wildlife.     

The Role of Pressure Drop and Flow Redistribution on Modeling Mercury Control Using Sorbent Injection in Baghouse Filters

Abstract

A mathematical model based on simple cake filtration theory was coupled to a reviously developed two-stage mathematical model for mercury (Hg) removal using powdered activated carbon injection upstream of a bag-house filter. Values of the average permeability of the filter cake and the filter resistance extracted from the model were 4.4× 10^?13 m² and 2.5 ×10^?4 m^?1, respectively. The flow is redistributed during partial cleaning of the filter, with flows higher across the newly cleaned filter section. The calculated average Hg removal efficiency from the baghouse is lower because of the high mass flux of Hg exiting the filter in the newly cleaned section. The model shows that calculated average Hg removal is affected by permeability, filter resistance, fraction of the baghouse cleaned, and cleaning interval.     

Modeling sorbent injection for mercury control in baghouse filters: II--pilot-scale studies and model evaluation

Activated carbon injection for Hg control in a 500-lb/hr pilot-scale coal-fired furnace equipped with a fabric filter for particulate control was evaluated at different operating conditions. The pilot-scale tests showed that Hg removal was improved at lower temperatures and higher C/Hg ratios. The two-stage mathematical model developed to describe Hg removal using powdered activated carbon injection upstream of a baghouse filter was used to obtain Langmuir isotherm parameters as a function of temperature by fitting the model to a subset of experimental data. The predictive capability of the model was then tested by comparing model calculations with additional experimental data from this system obtained using different operating temperatures and sorbent to Hg ratios. Model predictions were in good agreement with experimentally measured Hg removal efficiency. Based on the model predictions, Hg removal in the duct appears to be limited and higher C/Hg ratio, lower operating temperature, and longer cleaning cycle of the baghouse filter should be utilized to achieve higher Hg removal in this system.