No abstract

Chloramine decays in distribution system due to wall and bulk water reactions. In bulk water, the decay could either be due to chemical or microbiological reactions. Without such distinction it is not possible to model chloramine decay in an actual distribution system since microbiological decay depends on different factors compared with chemical decay. The dependence of chloramine decay on chemical reactions is mostly understood. Although it is widely accepted that microbiological reactions could accelerate chloramine decay, quantification had not been possible until the microbiological decay factor method was proposed. In this paper, the effect of temperature on microbial and chemical decay coefficients is presented. This was done by following the procedure of the microbiological decay factor method but by varying the temperature of incubation between 18 and 30°C. The procedure was repeated for several samples. The results indicated that it is possible to express temperature dependence of both microbiological and chemical coefficients using the Arrhenius equation within the tested temperature range. Estimated E/R values were found to be 3,551±705 K−1 and 6,924±1,700 K−1 for chemical and microbiological decay rates respectively. Traditionally, it is believed that every 10°C rise would double the decay rate coefficients. However, the E/R value estimated in this study shows that a 16–17°C temperature rise is needed to double the chemical chloramine decay rate. A possible application to predict residuals in summer using winter water quality results is demonstrated. Results indicated that microbial decay factor method could help pre-warning water utilities of possible residual loss in summer. Traditional indicators could not offer such distinction.

Water utilities dose copper in drinking water systems to inhibit/kill microorganisms including algae. Under conditions observed in the systems, the majority of dosed copper is reported to be in dissolved forms of Cu-NOM and inorganic compounds. High concentrations (40 mg/L) of ferric salts are reported to be able to remove large amounts of copper. However, the fate of dissolved copper when a small amount of ferric salts (,2 mg/L) is present in natural water or in the distribution pipes when they are released from the corroded iron pipes are not known. The current paper investigates the mechanisms behind the dissolved copper removal in NOM-containing bulk water.When copper was dosed from 250-800 mg-Cu/L, relatively high solubility was demonstrated in Mundaring water, with dissolved copper increased from 250-720 mg-Cu/L. Both ferric chloride and ferric hydroxide were found to have a considerable ability to remove dissolved copper while the former showed higher capacity. Ferric chloride showed a linear relationship with copper removal (R 2 ¼ 0.99) and the removal by ferric hydroxide showed excellent agreement with either the Freundlich (R 2 ¼ 0.98) or Langmuir (R 2 ¼ 0.99) adsorption isotherm.

This report presents results from the Limestone Injection Multistage Burner (LIMB) Demonstration Project Extension. LIMB is a furnace sorbent injection technology designed for the reduction of sulfur dioxide (S02) and nitrogen oxides (NO=) emissions from coal-fired utility boilers. The testing was conducted on the 105 MWe, coal-fired, Unit 4 boiler at Ohio Edison's Edgewater Station in Lorain, Ohio. In addition to the LIMB Extension activities, the overall project included demonstration of the Coolside process for SO= removal for which a separate report has been issued. The primary purpose of the DOE LIMB Extension testing, which began in April 1990, was to demonstrate the generic applicability of LIMB technology. The program sought to characterize the SO2 emissions that result when various calcium-based sorbents are injected into the furnace, while burning coals having sulfur content ranging from 1.6 to 3.8 weight percent. The four sorbents used included calcitic limestone, dolomitic hydrated lime, calcitic hydrated lime, and calcitic hydrated lime with a small amount of added calcium lignosulfonate. The original EPA project focused on tests with calcitic hydrated lime while burning a D 3.0 weight percent sulfur Ohio coal, although tests with the lignosulfonate-doped material were added after pilot studies appeared to show enhanced reactivity. The results indicated SO2 removal efficiencies of greater than 70 percent are possible while operating at a close approach to the adiabatic saturation temperature of the flue gas. Efficiencies on the order of 60 percent were found in tests without close approach operation. The results presented in this report include those obtained for the various coal/sorbent combinations. They further characterize the SO2 removal to be expected with and without humidification to close approach to saturation over a range of calcium/sulfur stoichiometries. The effects of injection at different elevations in the furnace are explored, and in the case of limestone as the sorbent, the influence of particle size distribution is quantified. This report also addresses the effects of the LIMB process on boiler and plant operations. The increased particulate loading in the boiler and downstream equipment has the greatest impact on operations. Without effective sootblowing, heat transfer rapidly degrades when the lime sorbents are used. Particulate removal equipment must be capable of handling the increased D°°°I 1! loading. Moreover, the quicklimecomponent of the ash requiresthat precautionarymeasures be taken to avoid and/or minimize potential difficultiesfrom steaming and high pH conditions in service I water when handling and transportingthe ash. B&W DRB-XCLTM low-NO= burnerswere used throughout the project as these had been installed as part of the original EPA LIMB demonstration. The report discussesthe resultant NO, emissioncontrol in light of such operationalparameters as load, excess air, and pulverizers/burners in service. These variables were monitored more carefully duringthe current dem...

This report presents results from the Limestone Injection Multistage Burner (LIMB) Demonstration Project Extension. LIMB is a furnace sorbent injection technology designed for the reduction of sulfur dioxide (S02) and nitrogen oxides (NO=) emissions from coal-fired utility boilers. The testing was conducted on the 105 MWe, coal-fired, Unit 4 boiler at Ohio Edison's Edgewater Station in Lorain, Ohio. In addition to the LIMB Extension activities, the overall project included demonstration of the Coolside process for SO= removal for which a separate report has been issued. The primary purpose of the DOE LIMB Extension testing, which began in April 1990, was to demonstrate the generic applicability of LIMB technology. The program sought to characterize the SO2 emissions that result when various calcium-based sorbents are injected into the furnace, while burning coals having sulfur content ranging from 1.6 to 3.8 weight percent. The four sorbents used included calcitic limestone, dolomitic hydrated lime, calcitic hydrated lime, and calcitic hydrated lime with a small amount of added calcium lignosulfonate. The original EPA project focused on tests with calcitic hydrated lime while burning a D 3.0 weight percent sulfur Ohio coal, although tests with the lignosulfonate-doped material were added after pilot studies appeared to show enhanced reactivity. The results indicated SO2 removal efficiencies of greater than 70 percent are possible while operating at a close approach to the adiabatic saturation temperature of the flue gas. Efficiencies on the order of 60 percent were found in tests without close approach operation. The results presented in this report include those obtained for the various coal/sorbent combinations. They further characterize the SO2 removal to be expected with and without humidification to close approach to saturation over a range of calcium/sulfur stoichiometries. The effects of injection at different elevations in the furnace are explored, and in the case of limestone as the sorbent, the influence of particle size distribution is quantified. This report also addresses the effects of the LIMB process on boiler and plant operations. The increased particulate loading in the boiler and downstream equipment has the greatest impact on operations. Without effective sootblowing, heat transfer rapidly degrades when the lime sorbents are used. Particulate removal equipment must be capable of handling the increased D°°°I 1! loading. Moreover, the quicklimecomponent of the ash requiresthat precautionarymeasures be taken to avoid and/or minimize potential difficultiesfrom steaming and high pH conditions in service I water when handling and transportingthe ash. B&W DRB-XCLTM low-NO= burnerswere used throughout the project as these had been installed as part of the original EPA LIMB demonstration. The report discussesthe resultant NO, emissioncontrol in light of such operationalparameters as load, excess air, and pulverizers/burners in service. These variables were monitored more carefully duringthe current dem...