ASTM_F_1522_-_95_2001.pdf

Designation:F 1522 95(Reapproved 2001)Standard Guide forUse of the Steam Stripping Process in Mitigating ChemicalSpills1This standard is issued under the fixed designation F 1522;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide covers the considerations for the use of steamstripping in the mitigation of spilled chemicals(includinghydrocarbons)dissolved in ground and surface waters.Aes-thetic and socioeconomic factors are not considered;although,these and other factors are often important in spill response.1.2 This guide addresses the application of steam strippingalone or in conjunction with other technologies.1.3 In making decisions with regards to discharging treatedwater and operating a boiler,appropriate government authori-ties must be consulted as required by law.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.In addition,it is theresponsibility of the user to ensure that such activity takesplace under the control and direction of a qualified person withfull knowledge of any potential or appropriate safety and healthprotocols.2.Terminology2.1 Definitions:2.1.1 feed-to-steam ratioratio of feed flowrate(byweight)to steam flowrate(by weight).2.1.2 foulantssubstances,such as clay or silt,microbialbiomass,organic solids or film,inorganics,and naturallyoccurring compounds,that interfere with the desired process.2.1.3 Henrys lawwhen a liquid and a gas are in contact,the weight of the gas that dissolves in a given quantity of liquidis proportional to the pressure of the gas above the liquid.Thelaw holds true only for equilibrium conditions,that is,whenenough time has elapsed so that the quantity of gas dissolvedis no longer changing.2.1.4 Henrys law constanta function of the compoundssolubility in the liquid phase and its volatility.A high Henryslaw constant indicates equilibrium favoring the gas phase,thatis,the compound is more easily stripped from water than onewith a low Henrys law constant.Theoretically,Henrys lawconstant can be estimated from vapor pressure,solubility,andmolecular weight as follows(1):2HC 5Vp3 MW 3 16.03sol 3 T(1)where:HC=Henrys law constant(atm m3water/m3vapor),Vp=vapor pressure(mm Hg),MW=molecular weight(g/mole),sol=solubility(mg/L),andT=temperature(K).2.1.5 inorganic foulantscompounds,such as those of iron,calcium,and manganese,which precipitate in a treatment unit,thereby reducing the throughput and efficiency of the process.2.1.6 packingis placed in a stripping column to increasethe available surface area for mass transfer.2.1.7 pHa measure of the acidity or alkalinity represent-ing the logarithm of the reciprocal of the concentration ofhydrogen ions.2.1.8 purge and trap techniqueuses an inert gas(such ashelium or nitrogen)to purge the compounds into a gaseousstate.2.1.9 removal effciencyinlet contaminant#2outlet contaminant#inlet contaminant#3 100%(2)2.1.10 semi-volatile organic compounda compound thatis amenable to analysis by extraction of the sample with anorganic solvent.It is used synonymously with Base/Neutral/Acid(BNA)compounds.2.1.11 steam strippinga separation process that utilizesdifferences in the thermodynamic properties of liquids.In thisprocess,steam and organic-contaminated water are fedcounter-currently to a packed column,causing the transfer ofthe contaminant(s)from the water phase to the vapor phase.The driving force for the separation is the concentrationdifferential of the organic component(s)between the liquid andvapor phases.Two streams are generated in this process,namely:bottoms(treated effluent)and tops or overhead(con-centrated contaminant).2.1.12 equilibrium vapor pressurethe pressure at which,at constant temperature,a pure substances vaporization,and1This guide is under the jurisdiction of ASTM Committee F20 on HazardousSubstances and Oil Spill Response and is the direct responsibility of SubcommitteeF20.22 on Mitigation Actions.Current edition approved May 15,1995.Published July 1995.Originallypublished as F 1522 94.Last previous edition F 1522 94.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.condensation rates are at equilibrium.2.1.13 volatile organic compounda compound amenableto analysis by the purge and trap technique.It is usedsynonymously with purgeable compounds.2.1.14 volatilitythe tendency of a solid or liquid materialto pass into the vapor state at a given temperature.3.Factors3.1 Removal efficiency is highly dependent