Document kDEmpZoYRBenXQZYGaLOr9gk0

Jt. & UB Copy ...No, 10 Date; ... ,10th. .J.anuaxau_19.62,_... File No. ; B. Ll Z20........ THE ASSOCIATED-JQCIEL .COMPANY ..LIMITED r es s abg h an d ..pr/5L.QBg^x.psrj^s;rr 2U1: THE DECONTAMINATION OF SLUDGE FROM LEADED GASOLINE STORAGE TANKS - EXPERIENCE TO THE END OF 1%T AUTHOR: E0 V. BROWETT APPROVEDt E. V, BROWETT SUMMARY: An account is given in this Note of two trials that have been performed according to the Ethyl Corporation procedure for the decontamination of sludge by weathering and of one trial in which potassium permanganate was used as docontaminant* Effective dccontansanation was not achieved, in any of these trials. JSlMmK" I, KV. H, Fo3Sott 2t Air, R, 0S GibsonAfenager, Engineering Dept,/Mar.%gjr, Production 3. yanagGYf Research & Development Bept,t Dept0, 4A1 Soles Manager 5 - 10e Secretary;, Company Safety Committee II. Mr0 E. V. Browett 12 - 14* Information Department,, KE" 0009771 It is necessary for Oil Companies to remove sludge from leaded gasoline storage tanks from time to time. The disposal of such sludge presents an increasingly difficult problem* This sludge is contaminated with T.E.L. and other organolead compounds any technique of disposal of the sludge must include effective decontamination. Standard practice to date has been to fcury this material but space for "burial grounds" is difficult to find at seme refineries. Ethyl Corporation have recommended a method of disposal in which the sludge is allowed to "weather" in the open for a few weeks and it is claimed that decontamination is 'thereby effected* This Ndte outlines the Company's experience with the "Weathering" technique and with a proposed method involving decontamination of the sludge by treatment with potassium permanganate. Neither method appears to give satisfactory results,. DSCQNTAKIimQIL3I,-^IH^njG 2.1 Procedure During I960, Ethyl Corporation published a procedure for the decontamination by weathering of sludge from lei+ded gasoline storage tanks. Essentially, this procedure involves spreading the sludge in a layer of not more than three inches in thickness on the ground. The site selected may be bare ground or it may be covered with grass or with concrete. It must be fairly smooth and sufficiently well drained to prevent water-logging and should be so located that air can circulate freely over the surface of the sludge0 It is stated that the spread sludge must be left for ? t least four weeks, after which it mar be treated as any other non-toxic waste material. The four week period applies when the ambient tempoiature is above 32F ., and during tills time exposure to the sun is stated to be desirable but not mandatory- The safety precautions deemed t -o be necessary are also given. Ethyl Corporation provided figures shoving reductions in total organic lead as below Pour inches thick patch (l) 43,,3 p,.p,m. to 0.3 p.p.m. in 31 days. (2) 377 p.p.m. to 19.6 p.p.m. in 42 days. Two inch thick patch (1) 38.2 p..p,m, to 0,6 p.p.m. in 31 days. (?,) 456 p.p.m. to 2.7 p.p.m. in 42 days. In each of these cases, values ai-e given separately for T.E.L, and "other organic lead", those for "other organic lead" being low and approximately constant in each of these four trials. The remarkable reductions in the total organolead content of those Bludges are due to the reduction of the T.E-L. content in each case. K 0009772 -2 - 2=2 AadyUc^Methgteja^^ Etjasa figragg&ktoa Attached to the oopy of the procedure for decontamination by weathering, received from Ethyl Corporation in i960, was a oopy of their Analytical Procedure No.192* This is a method for the determina tion of organic lead confounds in gasoline storage tank iltidge, in which tetraethyl lead aid "other organolead compoundsM are determined separately. Investigations in our laboratories showed that this method did not differentiate quantitatively between T.E.L. aid triethyl lead salts. Ethyl Corporation were approached.in aid~196l on this point and in August* 19&Lj we received their reply acknowledging that cur findings were correct, but stating that their Analytical Procedure No,192 was applicable only to samples: containing less than 10 p.p.m. organic lead. They also sent a copy of "Determination of tetraethyl lead and its decomposition products in gasoline storage tank sludge* which comprised four analytical procedures, "A*, "B*, *0" and *D*. Procedure "D* was the same as Analytical Methcd No.192, but with a number of footnotes which had not been on the previous version. Procedures "A*, and aC" together enable the tetraethyl lead; triethyl lead and diethyl lead contents of a sludge to be determined. We have found these procedures to be reliable and have used them in seme of the more recent work reported below, These methods have been of greet value to us. 2.3 Weathering trial carried..oufr in France Ehrly in 1961, a trial ms carried cut at a Mobil Oil depot at Haut-Indre, near Nantes, in which sludge from a leaded gasoline storage tank was allowed to "weather86 Periodic determinations of the total organic lead content were undertaken by Octal-Kuhlaann at Paimboouf. the analytical method used consisted of extraction of the sludge with banaene followed by destruction of the organic matter and gravimetric determination of the extracted lead. Thus results obtained are tabulated below:- Bsfl&to, -r Aafttagm. .telae. Exposure time /g removed from tank One month IP days 50 days 60 days 70 de&k 00 day?* 90 daya 100 dayo, 100 dayfl, after mixing 110 dayp I1C dayp, after mixing 130 days; 130 days' Total organic lead,p.p.m. ' ; ! i* j . ; , ! i i j i 190 200 200 170 m 70 110 . 140 150 34P 140 200 140 SCO 1 \ ! 1 j1 < * 1 i Kf 000977.3 -3- Tbusp there was no significant reduction in the organic lead content of the sludge after weathering for about four months. This is certainly inconsistent vith the claims made by Ethyl Corporation. jfeg&^jagU'tg&L gs^<A.aa.t,l..st.?sHlgr This triel wag started during the first week in September, 19&U The sludge used was taken from a tank of 96,000 barrels capacity that had been titled for several different grades of gasoline. The amount of sltidge in the tank was rather less than had been expectedo The site selected for the weathering trial wa a grassy patch a few feet outside the bund wall of the tank0 The t&afe ms washed down with water and the washings pumped to the weathering site. The excess liquid soon disappeared, mainly by natural drainage. The sludge was then trans ferred to the weathering site by wheelbarrows and spread in a layer about two inches thick. The total area covered wag about yards by 10 yards and of this, an area about four yards square was roped off separately and need as the test area. Half of this was raked over ones per week and the other half remained unraked. The weather during the period of the trial was typical of the English autumn and the temperature did not fall below 32?* at any time during this period. Duplicate samples of the "weathered sludge were taken periodically by Esso for analysis by themselves and by this Company in order to follow the progress in decoaitaaination, each sample comprising portions fro a number of different positions on the site. The samples taken or the 14th, 21st and 28th days that were submitted to this Company were extracted with methanol according to Ethyl Corporation analytical procedure *A* and the extract was divided into two parts, The total organic lead content was determined separately in each, portion - on one by the Ethyl Corporation analytical procedure WB* and on the other by a method developed in our laboratories in which the organic lead is converted to the inorganic state and then determined by a mixed colour dithiaoas method at pH 9*0. The other samples received were divided into two parts. One port was analysed by the Ethyl Corporation procedures d B*. Kb** other portion was extracted with a solvent comprising 5 parts by volume of rttaoaol &r4 2 part by volume of carbon tetracblccrideo The lead in the extract was then converted to the inorganic state and determined by the mixed colour dithiaone method. It can bs mm from Table 2 that the results obtained by tvro methods war in satisfactory agreement on most, but not all, of the samples. KE 000.9774 1 - 4- Rggylteof Total Organic Load. Detoralratlong During the Trial.st -.FftWlag i Exposure 1 time j in days | From tank j! 12 14 j7 1* 21 ? 28 ? 5i j 66 j 98 If -1x-6lumiAij ovrfugjraan*Aicv ilema/*dut sumai mmM. p 1 ____ Raked Portion...... ! Priffclnrt f ! Ass,Octal ! Ethyl Corp* As$* Octel Ethyl Corp, j method method method method 1 ! 149 159 1 228 207 j 172 156 1 182 184 1 156 162 1 135 i 118 191 170 ! 101 ! 85 1 138 165 i 80 | 1 86 ! ----- ------- 87 84 165 164 ! 167 167 135 132 202 188 150 161 115 156 109 . 138 94 144 93 173 83 74 72 76...... Certain samples taken during this trial were analysed by Ethyl Corporation procedures "AM# M3" and "C" in order to determine the relative amounts of T.E.L. and other organolead compounds present in the sludges, The results obtained, expressed as p.p.m, T.E.L. by weight, are given in Table 3 *T i-- Exposure time 2 14 159 21 l6l 28 129 98 ' '66 xmu. Other organs Head.... la*sJL "Other Orgn-uolesd* Hagafe,?d^POUQi^ Other , organs .T S. ha 4" ad. .. ...4 { -t 32 ! t 9 18 191 170 138 84 112 es 129 112 88 20. 9 3s: 8* Thus., it was shown that the bulk of the organole&d present in the sludge was present as tetraethyl lead. This is consistent with the results reported by Ethyl Corporation txit the rate at which the T.EeL. disappeared from the sludge during the weathering process wa3 very slew XE 0009775 .-5 - The claims made by Ethyl Corporation for the rate of decontamination vers clearly not substantiated, despite the fact that the conditions under 'which the trial was performed wore veil within the range of conditions laid down by Ethyl Corporation* 3. DBCONT&MimiQir BY POTASSIBK PI^ftAMTE IN AQtJEOUS ACETOUS 3rl laboratory experimental work 3.1.1 Treatment of sludge, with various,docontcminaiitA In October, 195$* Sales Manager* requested an investigation into the possibility of cheBiicsl decontamination of sludgo from loaded gasoline storate tanks. Laboratory trials were carried out in 1959 1 , ad a result of which it was concluded that the use of potassium permanganate and acetone might be the answer to thi3 problem. In this work, the effectiveness of decontamination was assessed by measurement of leadin-air concentration above the treated sludgo and the use of potassium permanganate and acetone reduced the lead-in-air values to aero. No analyses for organic lead content, before or after treatment, were carried out. It was recommended that this technique be investigated further and a field trial was eventually organised in 1961 (Section 3.2, below)B Meanwhile, other relevant laboratory investigations into the effect of potassium permanganate have been carried out. 3.1 o2 Lator eaaoerimental treatment Beraaaganfkte After the Ethyl Cksrporation methods of analysis ver mode available, they were used to examine sludge that had been treated vith potassium permanganate in the laboratory. Two samples of sludge were taken and two trials were performed on each. In each trials 25 g. of the 3ludge was treated vith 5 ml. of acetone and a weighed; amount of potassium permanganate. It was then shaken for two hours. Hydroxylmine sulphato and methanol were then added and the mixture shaken again to destroy the excess permanganate and simultaneously extract the organolead compounds , The extract was analysed according to the analytical procedures ''B" and and the results are given in Table 4. 0009776 -6- im&j* ,yith iatltf Before u_ - --------------Total organic Sludgy load as p0p,m. sample To2,L. Wfc. SQ&O^.g, ! A^ >*1! 377 337 1.5 2.5 bi i ! ... 80 80 1.5 2,5 Other orgnno Total organ f TiB.t. lead as lead as J p*pm. p.p.a. T.E.L. j p.p.a. T.E/j0 1 W 109 94 54 63 11 1 163 j j 157 33 j 3i i 64 4*+ i 38 ! 42 1 These results show that the organic lead content of sludge is considerably reduced by the type of treatment-, but that more severe cord itions and longer reaction times would be needed before the sludgo could be regarded as decontaminated*, It nay be noted that the values obtained for *othor organ load''-, ie diethyl lead and triethyl lead compounds, are much higher proportions of total organic lead than was the case when smplos obtained during the weathering trial were analysed by the sssno technique,, 3.2 Chemical desoataaina.tlon trial carried gst-SAJEaBjig It wag arranged that a field trial of the technique of deoontamimtiort by potassium permanganate should be undertaken at Favley, using some of the sludge from the same storage tank as that used in the weathering trial, A concrete mixer was charged with about 600-Xb,, of sludge, a sample cf which was taken for determination of its organic lead content. The sludge was nixed and a lead-in-air tost was mad by sampling the atmosphere inside the wiser barrels The attempted- decontamination was carried out la two stages. Firstly# a slurry of 6->ib0 of potassium permanganate in 2-gallons of asctone was added, followed by mixing for 45 mimteso Secondly, a further &-lb0 of potassium permanganate in 1-gallon of acetone was added, followed by & mixing >r a farther 75 sdnuteg- The contents @f tbs sixer were then allowed to stand overnight0 The gludgo be cam a darker brown colour during the permanganate treatment, possibly due to the oxidation of ferrous iron to the ferric state, but the addition cf the comparatively small volumes of acetone did not result in a separate liquid phase an any time during the trial* It was not possible, therefore, to see whether or not excess perKanganat was preseni-.. 0009777 7 Lead-in-air testa were d inside the miser and samples of sludge y' .'ere taken for organic load determination at the end of each stage and ala " -.star standing overnight, The results obtained are given in Table 5, TABLE 5 Sasulta of Analyses made during Chemical Dscontamination &*, Ja&flZ Samrd.ft ! Lead-in-edr test inside ! mixer u.Fbi/cuft- lo Before treateeat J 2o After first stage 1 After second Stage! 4o ftter standing j overnight j 1t > 20 12,5 3 <1 Total organ j lead content j of sludge as? j 159 j 47 j 4S f These results indicate a rapid reduction of the organic load content to about one third of the original level; but not down to a level that would indicate satisfactory decontamination? despite the very low lead-in-air concentration that was achieved. 4- DECQlffAHINATION ..SI HSAT.HB It is yell known that all organolead compounds arc thermally unstable and can be rapidly decomposed to inorganic lead compounds by heating to fairly high temperatures. Thus? it should be possible to d 9ntsinat sludge from loaded gasoline storage tanks by boating uidor controlled conditions. Such a -technique would be more certain in its operation than wanthertag or chemical deoontealmtion and may deserve sorloua consideration. 5. STANDARDS OF DZOOFTiltl NATION v. The information available from Bthyl Corporation about thoix "weathering* procedure includes excerpts from a Field Bulletin in which references are made tc the lovol to which the organic load content should r reduced. K* 0009778 8 For example: (l) ''Ll the sample taken after four weeks of weathering has a lead content of 0,002 vt* % or less* no ttere samples neod be taken". and (2) ''Whenever the weathered sludge analyses 0*002 vt* $ organic lead or lass, it may be considered safe and the sludge may then be treated as any other non-hazardous waste material", Thus, it appears that Ethyl Corporation accept a standard of 20 p.p.m. of organic lead (equivalent to about JO p.p.m, of T.E.L.) as indicati ng satisfactory decontamination* This is much less stringent than the standard s that have been applied by this Company from time to time in not dissimilar circumstances. When required to assess the toxic hazard associated with gasoline tank sludge that has been buried and may have to be removed, we have tended to regard samples containing organolead compounds in amounts down to the equivalent of 3 p.p.m, T.E.L. as presenting a toxic hazard0 There is obviously a mood to agree on a limiting organolead content below which this type of sludge may be considered safe to handle, Ary proposed decontamination procedure can then be designed to reduce the organo lead content `bo below the limit* 6. CONCLUSIONS The claims made by Ethyl Corporation for their procedure for docontarairi tlon by weathering have not boon substantiated by the results obtained from two trials in which this Company has had an interest - one in Franco and one in England* The one trial that has been performed using potassium permanganate aa the decontaminant .in the presence of acetone was not successful although a lower total organic lead content was attained ixi two hours by this technique than was achieved in two months by the weathering procedure* In order to assess the development of the permanganate method or any other procedure, it will be necessary to define "effective decontamination'' in quantitative terms of the final organolead content of the sludge. The limit quoted by Ethyl Corporation may be higher than this Company would be prepared to acceptc ^ 1 )$ Dejntsaismtion of gasoline storage tank sludge*, W. Towers, File Safe No, Gc12/3/15. K 0009779