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HomeMy WebLinkAboutWTR2700371(1) W-371 HIGHLAND 3/4 MG & MT. OLIVET 3 MG TANKS WTR-11 1 #2 Cathodic Protection Final Report 11 6"4pll B �GRipNNI NGini1i i OF FILE FILE TITLE ca+kc cl It �� F7i rual RePoRf CH2M EHLL �ngin"f, r,:ononn+r: �utnh5b 16 January 1976 Mr. '::arre❑ L. Connason Public Works Director City of Renton City hall Renton, Washington 98055 Attention: Mr. Richard C. Roughton Utilities Engineer Gentlemen: Subject: Report on Inspection= of Cat9rodic Protection Systems - 'it. Olivet and highlands Water Storage Tanks This letter and the appended data constitute our report on the, inspections made of the cathodic protection sy•stems in the It. Olivet ground level reservoir and the hi,,jilands elevated tank. The inspections were made during [lie ,,,kb of i3 July 1977 a,ad 29 August 19%7. '.his rc:uort also includus a suiraary of tiw inspection -.-ide of, the. interior of. the Mt. Olivet reservoir on 12 Novarber i976. 'Me work described in this report was carried out in accord- ance with our letter dated 6 December 19i6 and vour subse- quent :.athori::ation dated 8 December 1916. [r.s,ec[ion of Ga tiwdic Protection System - t. tvet eservoa.r The '1t. Olivet cathodic protection system was checked on 19 July 191, and was found off. An inspection of tile. rectifier circuitry revealed a burned wire. 'he malfunc- tion was corrected and the cathodic protection systeio was re.-en,?-,jzed. 'The rectifier output We'- s�'t at '4U volts :[r. 4arren C. Gonnason page -2- IS January 1975 and ,' amperes of current. The potential of the interior of t::e reser oir was measured with respect to the permanent zinc reference electrode inside the reservoir, as rec. :ded on data sli.-e.t No. 1 included in the appendix of this report. A potential profile of the inside reservoir wall was ciade, as recorded on data sheets No. 2 and 3. This potential profile was made by lowering a copper/copper-sulphate (Cu'CuSO4) reference electrode into the water throuah the pertv.nent zinc reference electrode hole in the too: of the reservoir. The reservoir wall-to-CuCuSO4 reference elec- trode potential was then recorded every two feet as the electrode was raised from the bottom of the reservoir to the top. This potential profile showed excellent protection levels along the tank wall from four feet off the bottoa to the top. The potentials at the bottom of the reservoir, how- ever, had not yet reached corrosion control criterion (-0.55 volts). The current flow to the individual rings of .!nodes was checked, and a sample of water was taken from the reser- voir for measurement of resistivity and pH. the results of these tests are shown on data sheet No. 4. Un 20 July 197i , the rectifier output and the structure- to-zinc reference electrode potential at the 'it, Olivet reservoir were again checked. 111V reCtitler output was - increased to provide more adequate protection, as recorded on data short No. 5. rho Mt. Olivet cathodic' protection system was allow=d to polarize for approximately 30 days and was rechecked on 29 August .977, The potential of the reservoir to the zinc rofcrencu electrode was measured and the; output of the rectifier was again increased (see data sheet No. l). Another POte«tial profile of the inside. reservoir wall was rue:, as shown an data Sheets No. and S. r.-w potentials were well above corrosion control criterion, with excellent potential levels in the bottom of the reservoir. The current flow to the individual anode rinks was checked, as shown on data sheet No. 9, and the rectifier output was left r.t 33 volts and 36.8 amperes of current. The reser- voir-to-zinc reference electrode potential was left set at 0.40 volts. Mr. Scarren C. Gonnason page -3- 13 January ,97E Inn ction of Cathodic Protection Svsten - it.�i4an s ovate Tan- ':his cathodic protecr'.un system was checked on 20 July 197-, . The "as found" rectifier output readings and tank-to-perman- ent zinc reference electrode readings are recorded on data sheet No. 10. Information concerning the resistivity and pH of the water in the tank on this date is also recorded on data sheet No. 10. l potential profile was run of the interior of the highlands Tank on 20 July 19i7, as shown on data sheet _>a. 11 . This potential profile was run in the same manner as the profile run of the 'it. Olivet Reservoir. The potentials alone the interior of the iii„h.anL!s Tank were well above corrosion control cr erion, with excellent protection indicated in the bottor +f the tank. NO chages were made in the operation of this cathodic protection system. Visual lnspection of Interior v, at. tylivet =escrvoi- While the Mt. (Tlivet 1cserv*Lr was em?Lv for piping mcdi- fications, an inspvc'.ion of the interior was made on 12 November 076. The. �ipinp modificatior. work in hided cnttin, out a section of t e reservoir flour and excavating a portton of the �il beneath the floor. Picture No. I it, the appeciaix shows the location where the• section of floor was rt�%nov,�d and the sandv, ,.avelly bedd:nY undiir tha, reservoir. The contractor working an the reservoir reported that theta was little or no corrosion found on the bottom of the tank floor section removed. file Ii11 tinder the floor was noted to be oiled sand of extremely hich r-si tivity, rtakin_ it relatively non-corrosive. Lxtensive pitting on Cic inside of ta;a floor piaLa in the vicinity of the excavation was noted. This -Itting, ever, was the result of corrosion activity that had oc<.0 rrax; prior to tine installation of the cathodic protecti.o-1 Fyst"!" and no active corrosion was found. The teservoir e+alls, support columns, and floor area wen= found to tc in relatively good condition with no active :Ar. .:arren C. Gonnason pave -4- 18 January 1978 corrosion noted. ;See picture No._). :!hite calcareous deposits were found throughout the reservoir at random locations where the tank coating had earlier deteriorated and corrosion had boon active, prior to the installation and energizing of the cathodic protection system. Picture No. 2 shows the calcareous deposits on one of the reservoir columns. Two samples of the calcareous deposits, one pale white and one darker in color, were removed and submitted to the C112M HILL Environmental Sciences Laboratory for semi- quantitative spectrographic analyses. The results of these analyses are shown on the laboratory test results sheet in the appendix following the pictures. As can be seen, the major components in the calcareous de- posits were calcium, ma esium, silicon, and iron, which are normal components of complex silicates and carbonates normally precipitated from water at locations where cathodic protection currents are entering the metal surface and pro- vidint control of corrosion. Conclusions and Reconnendati.ons Both the: Mt. Olivet Reservoir and the Highlands :ilevated Tank cathodic protection systems are tuncrionin,g properly and are I oviding adequate control of corrosion to the interior submerhed surfaces. " he anodes in both systems are discharging current evenly and hunts vary little deterioration or metal loss. _e,. pictur,, No. 4 in the appendix. The structure-to-reference electrode potentials in both tanks should be maintained as left :and as sho%m on data sheets 'io. G and 10. The importance of checking the cathodic protection systems every aonth to ensure that they are operitin.. properly can- not n over-emph.as i zed. If the cathodic protection ection systems are left off for lon;;er than 30 day; , arpolarication will. occur and serious corrosivn pitting; at lolidays and defects in the coating will Lake place at an accellerated rate. It is rrconimendcd that another complete inspection c: the cathodic protection sgst.ems be made e,ithin the next: t%,o years. Mr. Warren C. Gonnason Page _5_ 18 January 1978 Please do not hesitate to call if we can be of service in any way. ite s pec tfu l lyl submitted, Henry F. Galka Corrosion Control Gngineerin.- ceg Attachments :^+ t a e APPENDIX f . tot CLIENT G/TY OF Ad—S&77J11t. WASAI _FkOJE'TNC S %SXJ.frG __•1_cF_ LOCATION ME Ot/ Z i?- 77 WRT STRUCTu RE TO CU-CUS04 POTENTIAL READINGS NEAREST RECTIFIER L!T RESE/F1/jji�}° __ RECTIFIEROuTPUT dn2,huL� DFF _VOLTS. O AY-S RECTIFIER TEST LOCATION c..r7 OFF RECT ON `<�E - r 'i1-��►iE SiiIIL'iT __ i I ii I I � I I I I CLIENT.If 170' QdF "eV7'n_1 y W.4SAV PROJEIT NC 5 4G7©.A© «E±- cF_ LOCA'rmti A?7. CLiVEr, �QFSLRV?aP ,-;J-igr-7� STRUCTURE TO CWCUSOy POTENTIAL READINGS NEAREST RECTIFIER A7 RFSFR✓car _- RECTIFIER OUTPUT_...----VOLTS—�& AMPS RECTIf IERINTERRUPTED' IWO TEST LOCJ TION RECT OFF RECT ON ESG FTfM 0ti F7 ES 1 Z� Fr rr i CLIENT Cdrr Qr R'CNTGN_, WiQ.if/ cROJElTNO LOCATION AWL ? L/Vf> &ZS6ARV Me �PC7EN TfiOL f�A�LF/LF iG LLyf�.-.I�56d W�L.j �--� 'A�iN 5Y!�C {� STRUCTURE TO CUICUS04 POTENTIAL READINGS NEAREST RECTIFIER AT /PE_C B.,(v✓a,�___�_ _____,_ _ RECTIFIER OUTPUT _—_VOLTS AVF3 RECTIFIER TEST LOCATION RECT OFc RECI ON C'"TAGE `_/. 1v_!_... . - --.- -- i S .. . . s.mitc��ITy_DF_2�NlQN_1Y61ath,_. e.y2ZLW,&W Gv�E�vr FcDw r0 .QniQGBs R_ PG7/L/E� O(JTi2'JT — yG VO(TS H/ RmF+s �vrE� R//v4 (�.u' .vvOVCs) — Z(c. G rn✓ CEn/7FF' R.+G (/2 AvODE,S) — F. r✓ '-.'TF 1nFN�,.wa(� Tl4A'E/v 7'f?U .r.'.Gi/ �,ao M, Win.✓•'„f< : h JUN7/On/ a^Cr 7 ^J�/ TOP p�c Raid..'✓Oi,r �/ m✓ r / /W'9r�! Wlr TEk Si9A'TFi,E F17C// r�-Sa'�''✓✓':�' 9EY rs ri v,,l E SGL' Gam? -C� PN 7.0 CLIENT C/7Y OP loPe"rO-V- w.9su_ PR0JESTwc. S9�9©-.9g SkEEi�_CF_ LOCATION 1012f OL/kEr "--'Z t.PyC/ii+ — _ _—. TA?EN fl+GAw QA STRUCTURE TO CU/CUS04 POTENTIAL READINGS NEAREST RECTIFIER Q7 RFCiNK92e& _ RECTIFIER OUTPUT FO[JNL Qr- VOLTS 32_0 AMPS 22,Q_._.. RECTIFIER INTERRUPTED? "f2 TEST LOCATION RECT OFF RECT. 0% v tOLTAGE .rA�tc�utr. -76 --ri&r /tEr a,-r r 4TArd .j3--y --'--- �C-utK FfE+9L'�� 7O _�'4S:[S.76G_._RFcr✓11ES—CSLr.�7ur TO: _�._--_. .. ____-__.__ : ._____T S rA't� 7/yo rQ_-ldl._e�F. �Or/?_s! REXk%t(yq-2Q_.CuLC:e�s�-1._ ..�...__..- --- --•�-r1'__�.`1.�'. I I I I coax sa CLIENT C172 7F /SEV7'0,V WKSAI PROJECT NO .,t2f7 LOCATION Mf Qr/✓t_T f3f'IA✓G/.F' DATc E-Z9-7" STRUCTURE TO CU(CUS04 POTENTIAL READINGS NEAREST RECTIFIER -AT PE:EF,/l loe RECTIFIER OUTPUT —AT—'—VOLTS L�� ✓ AMPS RECTIFIER INTERRUPTED- .-_._—_ TEST LOCATION RECT OFF RECT ON G VOLTA,E_ i .IllTu w TEVs'�.CLfE:!f",ri— . _34. i 350 i i f/!+Tf :=EC F�.rifG ,�'7�J.' !E'L'?' •4T � I FORM 9G CLIENT L/T' _ 5' A26W720A/ PRO.IECTNO, LPF70,44, SNEE'_7 C=_ LOCATION QJIBT _P{.SER ND/+P -,,'__ o_.:-..y=77 �FbTL/!T/.iL ^512-is'C r"&V' `ltl"-) TA♦ EN �< STRUCTURE TO CUICUSO, POTENTIAL READINGS NEAREST RECTIFIER -.4�' .FESE4�c�nF RECTIFIEROUTPUT_ VOLTS._.:'..Z-..L_.AMPS RECTIFIER INTERRUPTEW_LI/—e - TEST LOCATION I RECT OFF r RECT ON I VOLTAGE 0.. coo/. . i r2 Fr i.Cr.N �PfTG�N I _Ii9z iFn � ,A 1i7F7 - .1 r;FFY _ 1,6 I CLIENT_CO'7Y 4- �ENTO�y/1� L✓4sff. --pRn�crr roq 59P�c 4g ShEEr h' ec LOCATION /fT eVci✓Er E�Evro./a _ 0A?= _r-29- 77 ��b�fN�64P /�P'Fi E ACL7/!6 Z'&0- -C/[L TAI:Eh^_r STRUC%PE TO Cu C_SCy POTENTIAL READINGS NEAREST RECTIFIER RECTIFIER OUTPUT T.. . _..__VOLTS PF. AMPS _�?A ,Q.4_ RECTIFIER INTERRUPTED? AlC TEST LOCATION REC? OFF PECT G': +OLTA(.E 17 iI t I i 19.77 C!',-ENT FtG..! Jt! .�Gl/OL16S .S ECTIF/E� L/L'71�UT 33 ✓Oi 73 3:5 au rcR (45 �INGLc�♦ - 1`!O ..s✓ C49V rd'p T/!J(s �✓j ANOOE t� 7 Z m ✓ i..�..�,✓ poi at- � C� fd_Ea C.F - �/= .,e.. � CLIENT C/Tr DF REN70Nf W-GSN PRDJtCT NO LOCATION OWA604L _� fr w9rE,r� Ti9NK —_-._ ca- 7-20- 77 TAI EN 9rac.r� STRUCTURE TO CUSUSO4 POTENTIAL READINGS NEAREST RECTIFIER 09T 'rO%Vir - RECTIFIER OUTPUT VOLTS AMPSQ RECTIFIER INTERRUPTED) TEST LOCATION RECT OEF I RECT ON G VOLTAGE Tp�z• TC- Z"4C RMe 44 e-C r3'.QG� G-T C Y _'"��.�J_.Y,_�D�._i 7)Z__ (AFOLi,V REf'nAA16 TO / y—� s i i i I i � I roRm P5 CLIENT L/TY OF ""TONS WgSty — for a.F _CF_ LOCATION &d mLi WW*) FLF�607'f/� T.WJ/f -_f� •.?D-77 1P©rEi✓719[ F7P06 /97 I/N f�aFFLfNCF EL/4ri���<�� TA/:ENE%� STRUCTURE TO CWCUSO4 POTENTIAL READINGS NEAREST RECTIFIER .9Y rgVMq' RECTIFIER OUTPUT VOLTS--2-0 AMPS RECTIFIER INTERRUPTED? A!I^ TEST LOCATION I RECT OFF I RECT ON ,� VOLTAGE ,Y� F7 FRnm arr am a_ _ i r� FT T I I r z� rs — ---- 2.90 22 FT �S' I I i u H w� 410 a O:r O C� u O � rl J G O CCU Uu CnJ � y O 6 GD 4 O u o y (n O m w� � .yY cOq N ' o 0 Y W � Y O N Y < F: o. 3 Support !It. Olivet : servoir. I.Iiite cal- areous deposits in areas where coating had deteri- orated and corrosion had previously been active. { Piltl:r. ..o. 4 Cathodic protection anode inside ?St. Olivet tle servoir. Anode in excellent con- dition witli very litt-e loss of metal. t . CH2'VANHILL ENVIRONMENTAL SCIENCES LABORATORY SEMI QUANTITATIVE SPECTROGRAPHIC ANALYSES Client: City of Renton Job No. : S9970.A6 Report to: Rank Galka Samples Received: November 1976 Laboratory Semple Number C-76-644 (page) C-76-645 (dark) Aluminum Al PPm 10 1,0400 Antimony Sb ppm ND ND Arsenic As ppm ND ND Barium Ba ppm ND NO Beryllium Be ppm NO ND Bi.;muth Bi ppm ND ND Boran B ppm ND NO Cadmium Cd ppm NO No Cal•,ium Ca ppm >50,000 30,000 Chromium Cr PPm ND 30 Cobalt Cc ppm ND ND Copper C : PPti 30 50 Gallium Ga ppm ND ND Gold Au ppm ND ND Iron Fe ppm 10,000 >50,000 Lead Pb ppm 500 500 Magnesium Mg ppm %50,000 20,000 Manganese Mn Ppri ND 300 Molybdenum Me ppm ND 50 Niobium Nb Ppm ::G NO Nickel Ni PPm 11D 50 Potassium K Ppm NO ND Silicon Si Ppm 30,000 30,000 Silver Ag ppm NO ND Sodium Na Ppm ND NO Strontium Sr ppm 700 300 Tantalum Ta ppm NO ND Thorium Th ppm ND NO Tin Sn pPm ND ND Titanium Ti ppm ND 50 Tungsten N PPm ND NO Uranium r, Ppm ND 14D Vanadium v ppm 10 10 Zinc Zn Ppm ND �Jp Reported by: C. Zadorojny WTA4w fif�Ys ENDING QFFI FILE k 01 � 3 ? 1 cmicilec ��2CtION # �. F' Nal RaPokt