Environmental Chemistry

Questions & Answers

The project requires to build a carbon capture and utilisation plant to capture the CO2 produced in the above power plant and convert the captured CO₂ to CO using renewable hydrogen. Calcium looping technology will be used, although a broad review of carbon capture technologies will be included in the report. The project is to produce a concentrated stream of CO₂ (over 95 Vol.%) which will then be used to production CO through hydrogenation. The design must ensure that the health, safety and environmental (HSE) risks are as low as reasonably practical (ALARP) and meet all current and reasonably foreseeable safety and environmental legislation. In addition, the process control scheme should ensure that the plant operates normally under full automatic control, and provide sufficient information for its performance to be monitored and optimised.


1. A military base is contaminated with a plume of dinitrophenyl acetate (DNPA) that has leaked from an underground storage tank. In order to understand the degradation potential, a colleague of yours measured the change in DNPA concentration over time in pH 5.0 and pH 8.5 solutions at 22.5 °C and for a temperature range of 17.7 to 30 °C (only for pH 5.0 solution, shown next to part d). (a) Determine the molecular formula and calculate the molecular weight of DNPA. Show ALL of your work for full credit.


(b) Determine the rate coefficients (kh) of the hydrolysis reaction at 22.5 °C for pH 5.0 and pH 8.5 by graphing the data. What is the reaction order and quantity of the two rate coefficients? Show all graphs and fit equations


(c) The pK of DNPA is 2.5. What is the fraction of DNPA in the protonated and deprotonated forms at pH 3.0?


(d) It has been observed that temperature has an effect on the reaction rate. Using the data below, calculate the Arrhenius activation energy (No; in units of kJ mol ‘) for the hydrolysis of DNPA at pH 5.0. Keep in mind that the Arrhenius equation can be written as Ink —— ——° — + c


(e) Without any information about DNPA, your colleague asks you what other reaction pathways might be possible to degrade ONPA if the contaminated groundwater eventually mixes with a nearby creek. To start the brainstorming process, in words, list some other possibilities of reactions in the environment and explain how these might degrade DNPA.


a) Calculate and report the total emissions of Hg to the atmosphere (from CFLS and industrial processes), and total emissions to soil and water in 2017. You'll need to convert units since Part 1 is in Ibs, and Part 2 is in kilograms. You can use the following conversion: 1 Ib = 0.454 kg. Please report your results in kilograms. b) Compare the quantity of emissions that are introduced into the environment (air, water,soil) between combustion and process emissions, and CFLS. Given that CFLS consume electricity during their use phase, they are also responsible for some of the electricity-derived Hg emissions released through electric power generation. Compare the emissions from using a CFL for one year to the Hg inside the bulb. Calculate for operation emissions of a bulb in the year 2011, assuming that the weighted average Hg emissions for 1 kWh of electricity production was 0.018 mgHg. A CFL with frequent operation will use approximately 100 MJ in a year. 3.6MJ = 1 kWh. Do the same calculation as above using 0.005 mg Hg/kWh, the emissions rate for electricity in 2017. This dramatic reduction was due to coal power plant closures as well as improved Hg emissions controls on coal plants that continued to operate. Compare the lifetime emissions of a bulb installed in 2011 (with a 6-year life) to the Hg released when a CFL breaks. To estimate lifetime electricity emissions for the CFLS, use the average of 2011 and 2017 annual electricity emissions rates.You are just calculating the emissions of Hg (you don't have to differentiate between emissions to air, soil and water).


CFL bulbs contain mercury in a gaseous, elemental form, with an average content of 3.5 mgHg/CFL. When broken, Hg is released from the bulb and can present a hazard to those exposed. CFL production grew rapidly between 2004 and 20084, at which point CFL demand continued to grow but at a slower pace. CFLS last an average of 6 years in use, so, for example,a bulb produced in 2004 is expected to retire (i.e., be discarded) in 2010. To calculate material flows in the year 2017, you'll need to know how many bulbs were sold and put into use in 2011.Approximately 400,000,000 CFL bulbs were sold in 2011, and 550,000,000 were sold in 20175. Assume that CFLS only break in the home when they are being installed or removed. Assume that 2% of all bulbs sold are broken during installation (i.e. have a lifetime of zero years),and 2% are broken during removal (i.e. after a lifetime of 6 years). Assume that Hg in broken bulbs goes directly to air or soil where the bulbs are broken. The other fates for CFL bulbs include disposal in the trash leading to land filling, and proper recycling. Only 15% of removed bulbs are recycled, the rest are broken or destined for landfills. Table 2 describes the environmental fate of mercury (either to air, soil and water, or back into production via recycling). Calculate the following mercury stocks and flows (as illustrated on the MFA diagram) for the year 2017. Please report values in kilograms rounded to the nearest whole number. a) Assuming that all CFLS sold before 2011 have already been discarded, use Table 1 to calculate The total in-use stock of Hg in CFLS in 2017. Note that 1 kg = 103 g = 106 mg. ii)that have reached 6 years of age are discarded. By convention, a net addition to stock is reported as a positive number, and a net decrease to stock as a negative number. Report your results in kg.The net addition to in-use stock (Ns) of Hg in the year 2017. Assume all bulbs Calculate B (Hg from broken CFLS), and the quantity of Hg to air and soil/water. Report your results in kg. c) Calculate D Landfll, the amount of Hg discarded to landfill, and the quantity to air and soil/water. Report your results in kg. Calculate D Recycling, the amount of Hg recycled. Report your results in kg. O Calculate the total addition of Hg to the atmosphere due to CFLS. Report your results in kg. Calculate the total addition of Hg to soil and water due to CFLS. Report your results inkg.


a)Give examples of human-made methods for the clean-up of oil spills in water. b)Detail and describe the chemical and physical processes that occur to oil when spilled in water.(0 morlke) c)Describe how microbes can be used to aid in the clean-up following an oil slick.


Part A: The result of a 7-day BOD test performed on a sample from an oligotrophic lake was 10 mg/1. The rate constant determined using previous studies was estimated to be 0.10d¹. Determine the ultimate BOD and 5-day BOD of the sample taken from the lake. Part B: Assume that the relevant chemical reaction in part A is as follows: Glucose(C6H12O6) reacts with oxygen to produce carbon dioxide and water. Estimate how much glucose (mg) was decomposed in the first 5 days in a water sample of 5 liters.


1. Alkalinity. (+6 total) Prior to the industrial revolution, the concentration of bicarbonate and carbonate in the ocean was 110 mg/L and 14.7 mg/L, respectively, and the pH was 8.2. a. Calculate the total alkalinity (in mg/L as CaCO3) of the ocean prior to the industrial revolution. b. Today, the pH of the ocean is 8.1. Assuming that the concentration of bicarbonate and carbonate has stayed relatively constant, has the alkalinity of the ocean increased or decreased since the industrial revolution?


An informal industry rule is to design occupied control rooms to withstand a 1-ton (907.18474 kg) blastof TNT at 100 ft (30.48 m). a) What overpressure does this correspond to? b) What quantity (in kg) of propane (C3H8) does this correspond to given that the energy of explosion for propane is 2043.1 kJ/mol, the molar mass of propane is 0.044 kg/mol and the energy of explosion of TNT is 4686 kJ/kg? c) How far away (in m) from this 1-ton blast must a residential home be in order to receive no more than minor damage to house structures? d) Estimate the length of the resulting flame if the equivalent propane gas is suddenly released(assume 1 s for the time of release) and ignites.ulu) e) Calculate the total rate of release of energy by the flame. (3 Marks)f) How close to the flame a person would need to be to experience skin burns given that skin burns requires an incident flux q of 100 kWm.2 for a 10-second exposure.(


1) Calculate the theoretical oxygen demand (mg/l) of a solution containing 450 mg of glucose(C6H12O6) in 2 liters of distilled water.


(a) What is meant by "Root Cause Analysis"? marks)(b) One graphical method of Root Cause Analysis is Fault Tree Analysis. Detail the stepsneeded to undertake a Fault Tree Analysis.(7 marks) (7 marks)(c) Figure 2 depicts a system for the treatment of a chemical plant effluent and its release to a watercourse. Effluent material from the plant should normally be treated in treatment tanks 1 and 2 (each tank removes different toxic chemicals) and then safely released, via outlet 1, to the watercourse. However, both treatments can fail, under circumstances shown in Table 1.In an emergency, if the system becomes over-pressurised, an emergency pressure safety valve (PSV) will activate to prevent a dangerous explosion. In this emergency scenario waste released should be collected in an overflow tank. However, on days where factory output is 20% higher than average, the overflow tank level can be exceeded, and toxic material will flow through outlet 2 into the watercourse. Table 1 shows the frequency and duration of the unwanted events. (i) Sketch a fault tree showing the scenarios that could lead to toxic material being released into the watercourse. You may assume that the high-output and the dangerous over-pressure condition are independent events. (9 marks)(ii) Calculate the frequency, per year, of toxic material being released from Outlet 1? (iii) Calculate the frequency, per year, of toxic material being released into the water course from either Outlet 1 or Outlet 2?(5 marks)


Half-life of a radioisotope. (+2.5 total) A lake in New Mexico was found to have radium-226concentrations of 50 pCi/L due to a nearby uranium mining operation. If no action is taken to remove the radium-226 from the lake, how long will it take to reach the federal limit of 5 pCi/L. Radium-226has a half-life of 1600 years. (Answer: 5,320 yrs).


Solids analysis is one of the important parameters for assessing water quality. Use the following data for calculating total solids (TS), volatile solids (VS), dissolved solids (DS),total suspended solids (TSS), and total volatile suspended solids (TVSS) all in mg/l. A sample volume of 150 ml was used in performing all solids analysis: Tare mass of evaporating dish = 24.3520 g Mass of evaporating dish plus residue after evaporation @ 105 °C = 24.3970g Mass of evaporating dish plus residue after ignition @ 550 °C:24.3850g Mass of Whatman filter and tare = 1.5103g Mass of Whatman filter and tare after drying @ 105 °C = 1.5439g Residue on Whatman filter and tare after ignition @ 550 °C = 1.5199g


Batch reactor with first order reaction. (+4 total) A researcher is attempting to produce ethanol using an enzyme catalyzed batch reactor. The ethanol is produced from corn starch by first-order kinetics with a rate constant of 0.05 hr1. Assuming the concentration of ethanol initially is 1 mg/L,what will be the concentration of ethanol (in mg/L) after 24 hours? Assume the reactor stays at a constant volume and temperature. How long will it take to reach a concentration of 10 mg/L ethanol?(Answer: C = 3.32 mg/L; t=46 hr).


Mass balance on a stream receiving waste. (+3.5 total) Let's revisit the BOD problem from the first homework. Instead of running a BOD5 experiment, an operator from the wastewater treatment plant provides you with the BOD5 and flowrate of the wastewater that spilled into the stream (BODWW =184.4 mg/L; Qww = 500 L/s). You find records that show the BOD5 and flowrate of the stream during normal conditions (BODS = 0.8 mg/L; Qs = 1000 L/s). Using this information, determine the BOD5 of the stream after the spill event, assuming steady state and no reaction. Begin by drawing and labeling a diagram of the system. (Answer: BOD5= 62 mg/L).


0 10 ml of wastewater is diluted to 1 liter, aerated and sealed. The initial dissolved oxygen level of the sample was 50 mg/1. The dissolved oxygen level after 5 days and 20 days were 40 mg/1 and 28 mg/1. Estimate the rate constant associated with the biological decomposition of the waste.


If the BODs of a waste is 220 mg/l and the ultimate BOD is 320 mg/l, what is the rate constant?


The Immediately Dangerous to Life and Health (IDLH) concentration is defined as the concentration"that poses a threat of exposure to airborne contaminants when that exposure is likely to cause death or immediate or delayed adverse health effects or prevent escape from such an environment." The IDLH implies a 30-min maximum exposure time. A table of transformation from percentage to Probits is given below: a) The IDLH for chlorine gas is 10 ppm. Estimate the fraction of fatalities due to exposure at the IDLH for 30 min given that the Probit equation for chlorine deaths is: P=-8.29+0.92 \times \operatorname{Ln}\left(C^{2.0} T\right) where Cis the chlorine concentration in ppm and Tis the time exposure in minutes. b) Estimate the maximum exposure or evacuation time to result in no more than 1% fatalities atthe IDLH level. c) Define the parameters LC10, LC50 and LC90. d) Determine the LC50 for a 10-minute exposure period. e) Determine the LC10 for a 50-minute exposure period. f) Give a definition of the threshold value limit (TLV). Specify the exposure that forms the basis of the definition of the TLV.13 Marks)


a) Using the thermal radiation equation below and your knowledge of solar flux calculate theflux emitted from a star with a temperature of 6200 K to 2.d.p. Assume the star is a perfectblack-body. The Stefan-Boltzmann thermal radiation equation is: P = AɛoTªWhere P= Power (W) ASurface area (m²) epsilon = Emissivity sigma =The Stefan-Boltzmann constant is 5.67 x 10-8 W · m2 . K-4= T = Temperature (K) (i) Explain, in this context, what is represented by the term 4ttr2? (ii) Explain, in this context, what is represented by the term a (iii) Redraw the diagram depicting the Earth's atmosphere as a single layer above theearth and add labels and direction arrows for the resultant fluxes (W/m2) under thoseconditions. (iv) Derive equations representing the temperature of the single atmospheric layer, and the temperature of the ground. State all the assumptions you have made.


a) State the four main principles of engineering ethics. b) State the three main methods used in accidents and loss statistics for measuring the effectiveness of safety programmes. c) The UK Legislative structure is multi-layered. State the difference between Enabling Acts,Regulations or Statutory Instruments, Guidance Notes and Codes of Practice. d) What is a source model? Give two examples of source models. What information can be obtained from source models? e) Explain how liquid flow rate through a hole in a vessel is calculated. What are the main contributions to the overall pressure driving the fluid out of a vessel for an aperture of a given area?


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