Nitrogen in Waters: Forms and Concerns
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Wastewater Technology Fact Sheet: Ammonia Stripping
United States Office of Water EPA 832-F-00-019 Environmental Protection Washington, D.C. September 2000 Agency Wastewater Technology Fact Sheet Ammonia Stripping DESCRIPTION Ammonia stripping is a simple desorption process used to lower the ammonia content of a wastewater stream. Some wastewaters contain large amounts of ammonia and/or nitrogen-containing compounds that may readily form ammonia. It is often easier and less expensive to remove nitrogen from wastewater in the form of ammonia than to convert it to nitrate-nitrogen before removing it (Culp et al., 1978). Ammonia (a weak base) reacts with water (a weak acid) to form ammonium hydroxide. In ammonia stripping, lime or caustic is added to the wastewater until the pH reaches 10.8 to 11.5 standard units which converts ammonium hydroxide ions to ammonia gas according to the following reaction(s): + - NH4 + OH 6 H2O + NH38 Source: Culp, et. al, 1978. Figure 1 illustrates two variations of ammonia FIGURE 1 TWO TYPES OF STRIPPING stripping towers, cross-flow and countercurrent. In TOWERS a cross-flow tower, the solvent gas (air) enters along the entire depth of fill and flows through the packing, as the alkaline wastewater flows it may be more economical to use alternate downward. A countercurrent tower draws air ammonia removal techniques, such as steam through openings at the bottom, as wastewater is stripping or biological methods. Air stripping may pumped to the top of a packed tower. Free also be used to remove many hydrophobic organic ammonia (NH3) is stripped from falling water molecules (Nutrient Control, 1983). droplets into the air stream, then discharged to the atmosphere. -
Ozonedisinfection.Pdf
ETI - Environmental Technology Initiative Project funded by the U.S. Environmental Protection Agency under Assistance Agreement No. CX824652 What is disinfection? Human exposure to wastewater discharged into the environment has increased in the last 15 to 20 years with the rise in population and the greater demand for water resources for recreation and other purposes. Disinfection of wastewater is done to prevent infectious diseases from being spread and to ensure that water is safe for human contact and the environment. There is no perfect disinfectant. However, there are certain characteristics to look for when choosing the most suitable disinfectant: • Ability to penetrate and destroy infectious agents under normal operating conditions; • Lack of characteristics that could be harmful to people and the environment; • Safe and easy handling, shipping, and storage; • Absence of toxic residuals, such as cancer-causing compounds, after disinfection; and • Affordable capital and operation and maintenance (O&M) costs. What is ozone disinfection? One common method of disinfecting wastewater is ozonation (also known as ozone disinfection). Ozone is an unstable gas that can destroy bacteria and viruses. It is formed when oxygen molecules (O2) collide with oxygen atoms to produce ozone (O3). Ozone is generated by an electrical discharge through dry air or pure oxygen and is generated onsite because it decomposes to elemental oxygen in a short amount of time. After generation, ozone is fed into a down-flow contact chamber containing the wastewater to be disinfected. From the bottom of the contact chamber, ozone is diffused into fine bubbles that mix with the downward flowing wastewater. See Figure 1 on page 2 for a schematic of the ozonation process. -
Prebiological Evolution and the Metabolic Origins of Life
Prebiological Evolution and the Andrew J. Pratt* Metabolic Origins of Life University of Canterbury Keywords Abiogenesis, origin of life, metabolism, hydrothermal, iron Abstract The chemoton model of cells posits three subsystems: metabolism, compartmentalization, and information. A specific model for the prebiological evolution of a reproducing system with rudimentary versions of these three interdependent subsystems is presented. This is based on the initial emergence and reproduction of autocatalytic networks in hydrothermal microcompartments containing iron sulfide. The driving force for life was catalysis of the dissipation of the intrinsic redox gradient of the planet. The codependence of life on iron and phosphate provides chemical constraints on the ordering of prebiological evolution. The initial protometabolism was based on positive feedback loops associated with in situ carbon fixation in which the initial protometabolites modified the catalytic capacity and mobility of metal-based catalysts, especially iron-sulfur centers. A number of selection mechanisms, including catalytic efficiency and specificity, hydrolytic stability, and selective solubilization, are proposed as key determinants for autocatalytic reproduction exploited in protometabolic evolution. This evolutionary process led from autocatalytic networks within preexisting compartments to discrete, reproducing, mobile vesicular protocells with the capacity to use soluble sugar phosphates and hence the opportunity to develop nucleic acids. Fidelity of information transfer in the reproduction of these increasingly complex autocatalytic networks is a key selection pressure in prebiological evolution that eventually leads to the selection of nucleic acids as a digital information subsystem and hence the emergence of fully functional chemotons capable of Darwinian evolution. 1 Introduction: Chemoton Subsystems and Evolutionary Pathways Living cells are autocatalytic entities that harness redox energy via the selective catalysis of biochemical transformations. -
Introduction to Co2 Chemistry in Sea Water
INTRODUCTION TO CO2 CHEMISTRY IN SEA WATER Andrew G. Dickson Scripps Institution of Oceanography, UC San Diego Mauna Loa Observatory, Hawaii Monthly Average Carbon Dioxide Concentration Data from Scripps CO Program Last updated August 2016 2 ? 410 400 390 380 370 2008; ~385 ppm 360 350 Concentration (ppm) 2 340 CO 330 1974; ~330 ppm 320 310 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 Year EFFECT OF ADDING CO2 TO SEA WATER 2− − CO2 + CO3 +H2O ! 2HCO3 O C O CO2 1. Dissolves in the ocean increase in decreases increases dissolved CO2 carbonate bicarbonate − HCO3 H O O also hydrogen ion concentration increases C H H 2. Reacts with water O O + H2O to form bicarbonate ion i.e., pH = –lg [H ] decreases H+ and hydrogen ion − HCO3 and saturation state of calcium carbonate decreases H+ 2− O O CO + 2− 3 3. Nearly all of that hydrogen [Ca ][CO ] C C H saturation Ω = 3 O O ion reacts with carbonate O O state K ion to form more bicarbonate sp (a measure of how “easy” it is to form a shell) M u l t i p l e o b s e r v e d indicators of a changing global carbon cycle: (a) atmospheric concentrations of carbon dioxide (CO2) from Mauna Loa (19°32´N, 155°34´W – red) and South Pole (89°59´S, 24°48´W – black) since 1958; (b) partial pressure of dissolved CO2 at the ocean surface (blue curves) and in situ pH (green curves), a measure of the acidity of ocean water. -
National Primary Drinking Water Regulations
National Primary Drinking Water Regulations Potential health effects MCL or TT1 Common sources of contaminant in Public Health Contaminant from long-term3 exposure (mg/L)2 drinking water Goal (mg/L)2 above the MCL Nervous system or blood Added to water during sewage/ Acrylamide TT4 problems; increased risk of cancer wastewater treatment zero Eye, liver, kidney, or spleen Runoff from herbicide used on row Alachlor 0.002 problems; anemia; increased risk crops zero of cancer Erosion of natural deposits of certain 15 picocuries Alpha/photon minerals that are radioactive and per Liter Increased risk of cancer emitters may emit a form of radiation known zero (pCi/L) as alpha radiation Discharge from petroleum refineries; Increase in blood cholesterol; Antimony 0.006 fire retardants; ceramics; electronics; decrease in blood sugar 0.006 solder Skin damage or problems with Erosion of natural deposits; runoff Arsenic 0.010 circulatory systems, and may have from orchards; runoff from glass & 0 increased risk of getting cancer electronics production wastes Asbestos 7 million Increased risk of developing Decay of asbestos cement in water (fibers >10 fibers per Liter benign intestinal polyps mains; erosion of natural deposits 7 MFL micrometers) (MFL) Cardiovascular system or Runoff from herbicide used on row Atrazine 0.003 reproductive problems crops 0.003 Discharge of drilling wastes; discharge Barium 2 Increase in blood pressure from metal refineries; erosion 2 of natural deposits Anemia; decrease in blood Discharge from factories; leaching Benzene -
Measurement of Cp/Cv for Argon, Nitrogen, Carbon Dioxide and an Argon + Nitrogen Mixture
Measurement of Cp/Cv for Argon, Nitrogen, Carbon Dioxide and an Argon + Nitrogen Mixture Stephen Lucas 05/11/10 Measurement of Cp/Cv for Argon, Nitrogen, Carbon Dioxide and an Argon + Nitrogen Mixture Stephen Lucas With laboratory partner: Christopher Richards University College London 5th November 2010 Abstract: The ratio of specific heats, γ, at constant pressure, Cp and constant volume, Cv, have been determined by measuring the oscillation frequency when a ball bearing undergoes simple harmonic motion due to the gravitational and pressure forces acting upon it. The γ value is an important gas property as it relates the microscopic properties of the molecules on a macroscopic scale. In this experiment values of γ were determined for input gases: CO2, Ar, N2, and an Ar + N2 mixture in the ratio 0.51:0.49. These were found to be: 1.1652 ± 0.0003, 1.4353 ± 0.0003, 1.2377 ± 0.0001and 1.3587 ± 0.0002 respectively. The small uncertainties in γ suggest a precise procedure while the discrepancy between experimental and accepted values indicates inaccuracy. Systematic errors are suggested; however it was noted that an average discrepancy of 0.18 between accepted and experimental values occurred. If this difference is accounted for, it can be seen that we measure lower vibrational contributions to γ at room temperature than those predicted by the equipartition principle. It can be therefore deduced that the classical idea of all modes contributing to γ is incorrect and there is actually a „freezing out‟ of vibrational modes at lower temperatures. I. Introduction II. Method The primary objective of this experiment was to determine the ratio of specific heats, γ, for gaseous Ar, N2, CO2 and an Ar + N2 mixture. -
Inhibition of Premixed Carbon Monoxide-Hydrogen-Oxygen-Nitrogen Flames by Iron Pentacarbonylt
Inhibition of Premixed Carbon Monoxide-Hydrogen-Oxygen-Nitrogen Flames by Iron Pentacarbonylt MARC D. RUMMINGER+ AND GREGORY T. LINTERIS* Building and Fire Research Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA This paper presents measurements of the burning velocity of premixed CO-HrOrNz flames with and without the inhibitor Fe(CO)s over a range of initial Hz and Oz mole fractions. A numerical model is used to simulate the flame inhibition using a gas-phase chemical mechanism. For the uninhibited flames, predictions of burning velocity are excellent and for the inhibited flames, the qualitative agreement is good. The agreement depends strongly on the rate of the CO + OH <-> COz + H reaction and the rates of several key iron reactions in catalytic H- and O-atom scavenging cycles. Most of the chemical inhibition occurs through a catalytic cycle that converts o atoms into Oz molecules. This O-atom cycle is not important in methane flames. The H-atom cycle that causes most of the radical scavenging in the methane flames is also active in CO-Hz flames, but is of secondary importance. To vary the role of the H- and O-atom radical pools, the experiments and calculations are performed over a range of oxygen and hydrogen mole fraction. The degree of inhibition is shown to be related to the fraction of the net H- and O-atom destruction through the iron species catalytic cycles. The O-atom cycle saturates at a relatively low inhibitor mole fraction (-100 ppm), whereas the H-atom cycle saturates at a much higher inhibitor mole fraction (-400 ppm). -
51. Astrobiology: the Final Frontier of Science Education
www.astrosociety.org/uitc No. 51 - Summer 2000 © 2000, Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, CA 94112. Astrobiology: The Final Frontier of Science Education by Jodi Asbell-Clarke and Jeff Lockwood What (or Whom) Are We Looking For? Where Do We Look? Lessons from Our Past The Search Is On What Does the Public Have to Learn from All This? A High School Curriculum in Astrobiology Astrobiology seems to be all the buzz these days. It was the focus of the ASP science symposium this summer; the University of Washington is offering it as a new Ph.D. program, and TERC (Technical Education Research Center) is developing a high school integrated science course based on it. So what is astrobiology? The NASA Astrobiology Institute defines this new discipline as the study of the origin, evolution, distribution, and destiny of life in the Universe. What this means for scientists is finding the means to blend research fields such as microbiology, geoscience, and astrophysics to collectively answer the largest looming questions of humankind. What it means for educators is an engaging and exciting discipline that is ripe for an integrated approach to science education. Virtually every topic that one deals with in high school science is embedded in astrobiology. What (or Whom) Are We Looking For? Movies and television shows such as Contact and Star Trek have teased viewers with the idea of life on other planets and even in other galaxies. Illustration courtesy of and © 2000 by These fictional accounts almost always deal with intelligent beings that have Kathleen L. -
Ammonia in Drinking-Water
WHO/SDE/WSH/03.04/01 English only Ammonia in Drinking-water Background document for development of WHO Guidelines for Drinking-water Quality _______________________ Originally published in Guidelines for drinking-water quality, 2nd ed. Vol. 2. Health criteria and other supporting information. World Health Organization, Geneva, 1996. © World Health Organization 2003 All rights reserved. Publications of the World Health Organization can be obtained from Marketing and Dissemination, World Health Organization, 20 Avenue Appia, 1211 Geneva 27, Switzerland (tel: +41 22 791 2476; fax: +41 22 791 4857; email: [email protected]). Requests for permission to reproduce or translate WHO publications – whether for sale or for noncommercial distribution – should be addressed to Publications, at the above address (fax: +41 22 791 4806; email: [email protected]). The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. The mention of specific companies or of certain manufacturers’ products does not imply that they are endorsed or recommended by the World Health Organization in preference to others of a similar nature that are not mentioned. Errors and omissions excepted, the names of proprietary products are distinguished by initial capital letters. The World Health Organization does not warrant that the information contained in this publication is complete and correct and shall not be liable for any damages incurred as a result of its use. -
Nitrogen Oxide Concentrations in Natural Waters on Early Earth
The First Billion Years: Habitability 2019 (LPI Contrib. No. 2134) 1042.pdf NITROGEN OXIDE CONCENTRATIONS IN NATURAL WATERS ON EARLY EARTH. Sukrit Ran- jan1,*, Zoe R. Todd2, Paul B. Rimmer3,4, Dimitar D. Sasselov2 and Andrew R. Babbin1, 1MIT, 77 Massachusetts Avenue, CamBridge, MA 02139; [email protected], 2Harvard University, 60 Garden Street, Cambridge, MA 02138, 3MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK, 4University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK, *SCOL Postdoctoral Fellow. Introduction: A key challenge in origin-of-life the fact that UV photolysis would not have occurred studies is determining the environmental conditions below the photic depths of these molecules. on early Earth under which abiogenesis occurred [1]. Results: We find that the sinks due to Fe2+ and While some constraints do exist (e.g. zircon evidence UV are orders of magnitude stronger than the sink due for surface liquid water), relatively few constraints to vents. Inclusion of the effects of these sinks sup- - exist on the abundances of trace chemical species, presses [NOX ]<1 µM in the bulk ocean over the vast which are relevant to assessing the plausibility and majority of the plausible parameter space. Oceanic - guiding the development of postulated prebiotic NOX -dependent prebiotic chemistries must identify - chemical pathways which depend on these molecules. mechanisms to concentrate local [NOX ] above the - - - - Nitrogen oxide anions (NOX ; NO2 , NO3 ) are oceanic mean. However, [NOX ] could have reached - chemical species of special importance. NOX are in- prebiotically-relevant concentrations (³1 µM) in fa- voked in diverse prebiotic chemistries, from the origin vorable surficial aqueous environments, i.e. -
WHO Guidelines for Indoor Air Quality : Selected Pollutants
WHO GUIDELINES FOR INDOOR AIR QUALITY WHO GUIDELINES FOR INDOOR AIR QUALITY: WHO GUIDELINES FOR INDOOR AIR QUALITY: This book presents WHO guidelines for the protection of pub- lic health from risks due to a number of chemicals commonly present in indoor air. The substances considered in this review, i.e. benzene, carbon monoxide, formaldehyde, naphthalene, nitrogen dioxide, polycyclic aromatic hydrocarbons (especially benzo[a]pyrene), radon, trichloroethylene and tetrachloroethyl- ene, have indoor sources, are known in respect of their hazard- ousness to health and are often found indoors in concentrations of health concern. The guidelines are targeted at public health professionals involved in preventing health risks of environmen- SELECTED CHEMICALS SELECTED tal exposures, as well as specialists and authorities involved in the design and use of buildings, indoor materials and products. POLLUTANTS They provide a scientific basis for legally enforceable standards. World Health Organization Regional Offi ce for Europe Scherfi gsvej 8, DK-2100 Copenhagen Ø, Denmark Tel.: +45 39 17 17 17. Fax: +45 39 17 18 18 E-mail: [email protected] Web site: www.euro.who.int WHO guidelines for indoor air quality: selected pollutants The WHO European Centre for Environment and Health, Bonn Office, WHO Regional Office for Europe coordinated the development of these WHO guidelines. Keywords AIR POLLUTION, INDOOR - prevention and control AIR POLLUTANTS - adverse effects ORGANIC CHEMICALS ENVIRONMENTAL EXPOSURE - adverse effects GUIDELINES ISBN 978 92 890 0213 4 Address requests for publications of the WHO Regional Office for Europe to: Publications WHO Regional Office for Europe Scherfigsvej 8 DK-2100 Copenhagen Ø, Denmark Alternatively, complete an online request form for documentation, health information, or for per- mission to quote or translate, on the Regional Office web site (http://www.euro.who.int/pubrequest). -
Hydrogen, Nitrogen and Argon Chemistry
Hydrogen, Nitrogen and Argon Chemistry Author: Brittland K. DeKorver Institute for Chemical Education and Nanoscale Science and Engineering Center University of Wisconsin-Madison Purpose: To learn about 3 of the gases that are in Earth’s atmosphere. Learning Objectives: 1. Understand that the atmosphere is made up of many gases. 2. Learn about the differences in flammability of nitrogen and hydrogen. 3. Learn what is produced during electrolysis. Next Generation Science Standards (est. 2013): PS1.A: Structure and Properties of Matter PS1.B: Chemical Reactions PS3.D: Energy in Chemical Processes and Everyday Life (partial) ETS1.A: Defining Engineering Problems ETS1.B: Designing Solutions to Engineering Problems ETS1.C: Optimizing the Design Solution National Science Education Standards (valid 1996-2013): Physical Science Standards: Properties and changes of properties in matter Earth and Space Science Standards: Structure of the earth system Suggested Previous Activities: Oxygen Investigation and Carbon Dioxide Chemistry Grade Level: 2-8 Time: 1 hour Materials: Safety glasses Manganese dioxide Work gloves (for handling Tea-light candles steel wool) Matches Test tubes Spatulas Beakers Wooden splints 100mL graduated cylinders Waste bucket for burnt 15mL graduated cylinders materials 3% hydrogen peroxide Vinegar Baking soda Safety: 1. Students should wear safety glasses during all activities. 2. Students should not be allowed to use matches or candle. 3. Students should be cautioned to only mix the chemicals as directed. Introduction: Air refers to the mixture of gases that make up the Earth’s atmosphere. In this lesson, students will learn about hydrogen (present in very, very small amounts in our atmosphere), nitrogen (the most prevalent gas), and argon (third behind nitrogen and oxygen.) Procedures: 1.