Pasadena's Sewage Disposal by the Activated Sludge Process vs. Proposed County Outfall to the Ocean Citation Alderman, Raymond Ellis (1925) Pasadena's Sewage Disposal by the Activated Sludge Process vs. Proposed County Outfall to the Ocean. Bachelor's thesis, California Institute of Technology. doi:10.7907/h3b6-ry90. https://resolver.caltech.edu/CaltechTHESIS:07312024-183350362 Abstract No abstract. Item Type: Thesis (Bachelor's thesis) Subject Keywords: (Civil Engineering) Degree Grantor: California Institute of Technology Division: Engineering and Applied Science Major Option: Civil Engineering Thesis Availability: Public (worldwide access) Research Advisor(s): Unknown, Unknown Thesis Committee: Unknown, Unknown Defense Date: 1 January 1925 Record Number: CaltechTHESIS:07312024-183350362 Persistent URL: https://resolver.caltech.edu/CaltechTHESIS:07312024-183350362 DOI: 10.7907/h3b6-ry90 Default Usage Policy: No commercial reproduction, distribution, display or performance rights in this work are provided. ID Code: 16604 Collection: CaltechTHESIS Deposited By: Benjamin Perez Deposited On: 01 Aug 2024 20:40 Last Modified: 01 Aug 2024 20:47 Thesis Files PDF - Final Version See Usage Policy. 18MB Repository Staff Only: item control page

THESIS PASADENA'S SEWAGE DISPOSAL BY THE ACTIVATED SLUDGE PROCESS ve. PROPOSED COUNTY OUTFALL TO THE OCEAN Raymond E.Alderma.n Claes of Nineteen Hundred Twentyfive Department of Civil Engineering CALIFORNIA INSTITUTE OF TECHNOLOGY Pasadena,California TABLE OF CONTENTS General Summary of Sewage Disposal Page I A Tri-City Outfall II 4 Fundamentals upon which estimates are based II 9 Curve of Populati0n and Assessed Valuation II IO The Activated Sludge Plant " II Taxes on Farm II I2 The Activated Sludge Plant (cont) II I3 Coste II I4 Coste (cont) Plans I,2,3, II I5 Plan NG.I II I6 Plan No.2 It I8 Plan No.3 II 20 Graph Showing Casts to Pasadena II 22 Charge a against and Profit on Plant II Resume'of Coets II 23 24 Incinerating Sludge,making farm unnecessary II 25 Graph Showin ~ Ceeta,Incinerating Sludge II 26 Th e Metropolitan Outfall to Ocean It 27 Graph Showing Outfall Plan No.I. II 30 Coste Plan No.I. It 31 Graph Showing Coate of Various Plans II Coet Conclusions II 33 34 Conservation of Water II 35 Ocean Beadles and their P~vtection II 37 Letter fDom State Beard of Health II 38 Human Element in Operati&n,Popular Sentiment II 44 General Conclusiens II 45 GENERAL SUMMARY OF SEWAGE DISPOSAL IN LOS ANGELES AND ORANGE COUNTIES. From careful studies which haTe been mad• of the topography of the City of Los Angeles adn the Ti cini ty it has been found that the natural flow by graTity to the ocean is diTided into two ~estions by an imaginary line,starting at about the boundary between Pasadena and Eagle Rock and extending in a southwesternly directiGn to a point just east of Vernon. Thence it runs southwestward to a point near El Segundo .. .All of the territory to the north and west of this line naturally drains to the western coast; and all the territory to the east and south drains to the southern coast witp the eaception of the beach cities between El Segundo and San Pedro. Thia fact alone eliminates from consideration any possibility of pasadena at any time finding an outlet to the ocean thru the great outfall sewer of Los Angeles,as Glendale has done. Glendale has purchased a certain capacity of the Los Angeles outfall by building and paying for about ten miles of the trunk sewer which joine the San Fernando Talley with the Loe Angeles outfall, Vernon and CUlTer City also haTe contracts with the City of Los Angeles for the disposal of their sewage. Burbank has just completed an internal sewer system discharging into an Imhoff tank diepoeal plant,located on a 40 acre sewer farm. The excess effluent ie ultimately dieposed of thru the L.A. outfall. Santa Ana,.Anaheim,Fullerton,Orange,Placentia,Garden GroTe and La Habra haTe built a joint outfall sewer to the ocean under a mutual contract agreement. -I- Pasadena, South Pasadena,Alhambra and san Marino haTe built an ActiTated Sludge disposal plant on the Pasadena city farm,under a mutual . contract agreement. The purified effluent is used on the city farm or discharged into the Rio Hondo. The sludge is for the most part disposed of as fertilizer on the city farm. llonroTia has an internal sewer system <l1li echarging onto a 50 acre sewer farm equipt with a Cameron tank. MonroTia is now planning a more modern sewage disposal plant in conjunction with Arcadia and -sierra Madre. The city engineer Mr.Gerlic stated that they were not considering the County eewer plan Tery seriously because they feel that the expense would be out of the question -at the present time. Whittier has an inte»nal sewer system discharging onto a 100 acre t'arm which is equipped with an Imhoff tank and sprinkling fiiter.The farm has -an outlet to Coyote Creek. The board of directors of Whittier ha.Te adopted a resolution to take initial proceedings toward forming a County Sanitation District for the purpose of joining the County outfall sewer to the ocean. CoTina,Azuza,Glendora haTe no sewer system at present- and haTe no definite plans for the :future. Pomona,Claremont and La Verne are now constructing an inter• nal system which will discharge into a tri-city farm to the southwest of Pomona.A modified actiTated sludge plant,known as the Elrod Systea will be installed under a mutual contract agreement.The sludge will be used as a fertilizer and the effluent for irrigation. Long Beach has an internal system discharging into the ocean at Alamitos Bay.The ocean currents,howeTer,are such that it is desirable to discontinue to discharge at that point and the City Council has passed a resolution in fa.Tor of disposing thru the proposed County Outfall Sewer to the ocean. Long Beach and Signal Hill are in County sanitation District #3 Practically all the territory in Loa Angeles County to the south and east of the City of Loa Angelee,with the exception of a fet cities as mentioned aooTe ha.Te no sewers at present and depend entirely on ceaa pools and septic tanks which may become a menace to the health of the country as it becomes more thickly set-tled. It is to relieTe this situation that the County has pro• posed the joint outfall under the new, act of the State Legislature,lmown aa Chapter 250 of Bill 191,adopted May 29,1923. This is an act authorizing the creation,goTernment and mainta•senance ot county sanitation districta,the issuance of bonds by such districts and the powers thereof. -3- - I n, ,( <,7 C J "! ,-- ~' I E, 1 A TRI~CITY OUTFALL. The natural drainage of the three cities is down the Rio Hondo to the Loa Angeles RiTer,thence thru the Dominguez Ranch to the Long Beach Harbor.The San Gabriel RiTer flows thru leTel land north of El Monte and while it sometimes flows down the llio Hondo into the Long Beach Harbor, it ueually flo 1R's thru another >channel near Whittier and out thru Alimitoa Bay. The ocean shore between San Pedro and Alimitos Bay is well built up for the entire distance,and any attempt to establish an outfall sewer Bite and treatment plant along this stretch would be vigorously contested by the cities and property owners in this section. The city of Loa Angeles owns a strip a mile in length along the coast at hheir outfall site. Yet with_ this added protection the State Board of Health is constantly receiving complaints from the adjacent cities.There a.re two possible locations for an outfa.11--one,at a point on the rock bound coast of the San Pedro Hills where there is no possibility of there eTer being any bathing beaches. The ocean currents are such that they will tend to take the screened eewa.ge outward into the ocean.The other location is east of Alamitos Bay.and therefore in Orange County.To turn raw sewage or eTen screened sev,age into the ocean at any point on the coast in this vicinity is nearly out of the question,unless it were taken as far as the mouth of the Santa Ana. RiTer.The Orange County outfall empties into the ocean at this point. An outfall of such length should be designed for a future of at least fifty(50) years and from a close study of pa.st growth and an estimate as to probable future growth,a population of at least 300,000 may be expected to be serTed by such a sewer. At present the population of the three citiee--Paaadena,South Pasadena,and Alhambra,is close to IIl,000 persons. Figuring I0O gal.per capita daily as a maximum and safe figure,t.he quantity to be carried by such a sewer at present and 50 years hence would be as · follows: P1:esent ca;eaoi ty_Reciui;ted HaTing II0,000 population at I00 gal.per day per capita would be equal to 11.000.000 gal per day. Figuring an I8 hour period in which this volume would be diacharged(the remaining 6 hours of the 24 ha.Ting negligible flow),this would equal a flow of 22.7 second feet,or with 50 miners inches to the sec, ft.,1,138 miners inches. Future Ga,»aoi tz B!Slt!ire<! In 1955 having a population of 300,000 and 100 gal.per capita per day,there would be 30,000,000 gal per day.Thie is equal to 62 sec,ft,or 3,100 rninere inoheso . Linear Peet of _PJ_pe Grade Size ,of P;Jl! Vel.of' Flow • 9-7.1, 45" 7. 5• 29,040 .25% 54" 5.4' 39,600 022% 5411 5.01 34,320 .07% 66" 3.3' 34,320 137,280 The above table is based on the possibility of finding a suitable location,aomeplace in the neighborhood of Alamicoe Bay. It is impossible to giTe an accurate of the cost of an outfall to the sea,without extensive field work,but from the aTailable maps an approxomate estimate can be made and approximate conclusions can be drawn. Suppose it were possible to obtain a site suitable for a treatment plant in the Ticinity of Alamitos Bay.The distance from thee southern boundary of Alhambss is approximatel y 26 miles.Such an outfall would be expensiTe to construct ae well ae to maintain, for it would be neoeaaary to croes two very erratic riTera,which seemingly change bheir course at wi 11 sometimes flowing in one channel and sometimes in another. The country in the vicinity of A Alamitos Bay and for three or four miles inland is marshy and therefore level. Ground water would probably be encountered which would increase construction coste,and the flatness of the country for such distances would add difficulties in the way of proper gradients. Condit~ons,along th~ lin~.of outfall 5.5 milee,drop in rt. 196---------gradient .67% ,. IOO 2nd. 7. 5 First II 6.5 4th. 6.5 3rd. It " 11 It " If II If· 75 25 " On Oct.23,1924 the 6ity of Glendale received the following bide per ft.for their new IO mile outfall to connect with the outfall of the City of Loe Angeles. Lowest Prices ---------Laying and :Material ExcaTating & Backfilling up to 15 ft. Total up to 15 ft. $ I0.22 $ II.25 7.86 7.86 7.86 $ I8.Q8 $ IQ.II f20,_86 $ 18.00 $20.00 High~st P~;_g~ Laying &Mat . ExcaTating & Backfilling 20-25 ft. deep I4,I2. t 32.15 Total -7- Assuming costs of$ 15.00 to$ 20.00 per ft .for the pipe installed and a length of 26 miles or 137,280 ft.the following rough estimates were obtained. Pipe Cost Inetal!!d $ 15.00/:rt. 137,280 rt. of pipe $ 20.00/rt. $2,060,000 $2,750,000 Ocean Outfall 400,000 400,000 Screening Plant 70,000 70,000 Right of way 50 acres @ $8,000 IO% Engineering Coets 400 000 3,620~003601nooo 3,98l5,o6o aoo,ooq. I, ooo 1nooo , $ 4 8 020LQ_QQ. ... t 4,980.,qoq_. 25% Contingencies TOTAL ESTIMATID CQ~~- 400.000 2,936,ood· 29_0 000 $ j,226~600 The 25% for contingencies is to allow for the crossing of the two streams and a poseiblie long inTerted cast Iron siphon(to insure permanent construction).This also takes into account the encountering of heaTy soile and ground water near the ocean shore. The tr0uble with this plan is that the cost is prohibitive. It would be out of the questien for them to spend as much as this. -8- FUNDAMENTALS UPON WHICH ESTIMATES ARE BASED - -- - . . . . . . . . .~ . , . . . . . . . . . . . . . . . . . . . . . . . ._ . . . . . . . . .. ....... ............. ~ ...... ~ - ~ . - . . . - . . . .. . . . . . . = - ◄- - - - - - -- MAXIMUM FLOW OF SEWAGE FOR DESIGNING COUNTY SEWER ...............- -......__ ,__ . ........,.~-........,...-.~ ~ . - . . re -e r e • •Ma~ . . - ~ ~ . . . . . . . , ~ - ee • -·• 1• ......_.,......, 80 gallons per oapita daily. AVERAGE FLOW OF SEWAGE FOR• · • DESIGNING PLANT .._ e •• -=-=- • ..-...• -• • • =~_............... . .. .DISPOSAL ,., ,. ., . e ••c1 re -_....-.......,....,~ re:rete-·• ·• c• ◄ =-• 55 gallons per capita daily. Used County Surveyors estimate. COST OF ADDITIONS TO SEWAGE DISPQ_§_AJ:,_f~Afil$ 60,000 per additional million gallons. OPERATING COST OF AQ~~~T.ER S~YDGE PLANT Without drying sludge--$ I4.00/mil.gal. Incinerating the sludge-$ 30.00/mil.gal. ESTIMATED SALE VALUE OF FARM $ I 0 900 g000 ESTIMATED TAXES ON CITY FARM - - - --- - - ,. ··-- .... 2# - Shown in table of taxes. BONDS County Sewer Bonds--40 year-• 5;.;,5% City Sewage Disposal Bonds--20 year--5% BASIS OF DIVISION OF COST OF OPERATING PLANT Pasa.dena--60% Alhambra--29% South Pasadena-•II% $l$E ' '''' ' c:i ' '' i0) 0 z ,H+ .,,,_- -:-t,-t- :Ii ' -I+ >- 0: I 1-1' I 0 :+ :?: Ul z • 0 t-1 0 11=1-r. ~ Ul <I) <I) t-+-r<-+t-+++++-++H-t-H+t-1++++ 1-+-t+t-!-H+Hi+ Ul '11 _J ..J UJ ...... ~ ++ Ul ""- ' :! . ', -t' ' _J H- + ij . +, Ef J::!:t-' l:it:!i ±ti:i-t+ct -it!::!: +R , --r,- , . . i ++- ~+ +c.;- ,+,--R +t J::t 1+ :ti:i:im µ I , Q::!:1:: II:i:r1_g_:+j-J-l-1-l. n::S: J. •+- -~ --++- +-4 - l+J-L.l-+i-+1- ++++*H---W+ 00$::n ~ :" , , M-' .,. '+ ~. #e-J. . . ' -t• + ' I+ ,1-l--+rr,++t, ;.+:++J-i-++t'++++-H -+++-H-H'++-1 -r..,,,+t-+-mw -· - . . ~>-t- ---1-ri+ I -+;....J. +t+t- ± ·i-+j: ~- m -. • 1-1 +t n ·H -1-H-Hi-+H- H-+++++-H-ri·~ +'+++i-+H-+ +t++++>++-1 .• 0 · 0 - ~ -J mt~~i++·l+H++ I~ "10 so 75 /00 /2.S- /SO /7.5 200 J!,ZS ,l~-o ,275 ASSE55£0 VALUATION(MILLIONS orOOLlARS) JOO THE ACTIVATED SLUDGE PLANT Operatien Casts: Without drying the sludge---#I4o00 per millien gallona 0 lnoineratimg the sludge-- - --$30.00 ft " " ATerage flow of sewage------ 55 gallens per day,per capita. - Year pop 2 o;t P§a. Mil 2 gal.oer daJ I9IO 28,000 1.$4 56200 1920 ,4,000 2o97 1930 88,000 • 1940 Per Ye~!:.,. 14 O;eera~!~ll_Q!.!! ,. t786o. o 1085.0 " l 5200 •.0 4.84 176800 tt 128,000 7.04 25700 0 . 24780.0 1950 178,000 9.35 3420.0 " 47900.0 1960 215,000 lI.,85 4320.0 ff 60600.0 36000.0 Taxee The present taxes and the estimated taxes are shewn •n the table that follawa.( See the next page) Addi ti one 1t? th~ .2resen-;, ,J?,l~.L If the City of Pasadena should decide to continue with the present activated sludge plant then in a few yea.re (about 1930) they will ha.Te to make additians in order to take care af the increased population. The preeent propoeed County Outfall will ,it is estimated, reach its capacity in 1944. Then a new sewer will be builto The City of Pasadena c ould therefore continue with their present plant until 1944 and then plan to join with that outfall. Or t hey can,if they deem it beet,plan to oantinue indefinitely , the activated sludg e plant. The estimated cost for both of these plans has been calculated and is shown on the gra ph whic h follows. -II• 26,000 36, 000 47,000 58,000 69 ,000 ·~ ooo 29,000 37 , 000 47,000 57 , 000 68,000 79,000 90,000 IOI ,000 I9.'~4 I929 1934 I939 1944 1949 I954 I959 1964 ~~ 24 , 000,000 Asses sed Valuation of Alhambra I924 40,000 ,000 34, 500 ,000 29 ,000,000 23 , 500 ,000 18,000,000 13,000,000 s ,000, 000 4 ,000, 000 Increase in Assessed Valua tion . over I924 .~~ 64,000,000 58,500,000 53,000,000 47 ,000,000 42 ,000,000 37,000,000 32 ,000,000 28,000,000 24,00Q,OOO 268's I '>24ci ...-~: :..; 22011. I" 198% 175% I o4% l. v .:>p - r7.. 17.c:j II71{ Per Cent Estimated of .Assessed 1924 Valuation Assessed Alhambra Valuation fp 13 ,000 Total Taxes on City FarmI924 • 12- increase in population . Ass-vmed ~~500,000 increase in a ssessed valuation per IOOO Note:- Actp:a,l Assessed Valuation of Alhambra in 1924= $ 23,090,075 80,000 16,000 8,000 !9~ Year Increase over Es timated Population of City of Alhambra C.AJ..OULATIOlrn FOB. .ESTI.M.ATED TAXES 01~ CITY :&'ARM 35 ,000 32,000 29,000 26,000 23,000 20,000 I 7 ,OOO 15,000 ~P I3 ,000 l!'arm. Estimated Total Taxes on City A Tery oonservatiTe estimate of the maximum average capacity of the present _a ctivated aludge plant 8,ooopooo gallons per day, Pasadena is entitled to 60% Of this or 4,800,000 gal.per day. On a basis of 55 gal,per capita per aay this capacity will be sufficient to last until the population is 87,000 persons. This population will be reached in 1930. Thus at the end of 1~29 or the beginning of 1930 it will be necessa :·ry to have ready for operation an additional unit to the present plant. The additions will be made in increments sufficient to last for an estimated period of ten years. At the end of this ten year p erio d the addition will not be obsolete and it will be st'ill .. be :: servi cable for aeme time. The bonds therefore will be twenty (20) year bonds. These bonds will be retired in the 20 years being paid off in 20 equal annual payments. I have computed tabulated and plotted a graph of the estim• ated coat of these additions. The estimated population of Pasadena at the various years was taken from the curves of population, The computatione are based on an estimated average flow of eew sewage o~ 55 gal.per capita per day. The cost of additions was taken as $60,000 per million gallons a.tided. -13- COST§ Tho Prea'!_?Jt Bo?!~ J..!~ Im 1924 there waa $392,000 due on the present bond issue This ie to be paid off in 19 equal annual installments. The bonds pay an interest of 4.5%. Year .An)ottnt J:?U9 1924 $392,000 1925 371, ,368 1926 • IJl1:.!Z:C!!L.. __ R19u9~ioq ;el~• ,Interest • 17,620 t 38,252 16,700 37,332 350,736 15,800 36,432 1927 330,.!04 14,850 35,482 1928 309,472 13,900 34,532 1929 288,840 13,000 33,632 1930 268,208 12, IOO 32,732 1931 247,576 II, IOO 31,732 1932 226,944 I0,200 30,832 1933 206,312 9,280 29,912 1934 185,680 8,350 28,982 1935 165,048 7,420 28,052 1936 144,416 6,500 27,132 1;37 123,784 5,570 26,202 1938 103,152 4,640 25. 272 1939 82,520 3,720 24,352 1;40 6i,880 2,780 23,412 I94I 41,256 I, 860 22,492 1942 20,420 920 21,522 1943 -----·- -----14• _........ CO~TS QF Tl,!E ~gTIVAt~~~DGE PLANT There are three plans for additiens to the activated elugge plant which I have investigated. They are shown on the graph of costs . . Plan No.:..L. This plan calls for additions of ten years,the addttion to be paid for by twenty {20) year bonds. The additions start in 1930 the work of construction being started in 1929 and the first payment being ~ade at the end of 1929. Plan no.I is shown in black on the curve. The main objection to this plan is that it does not distribute the costs evenly over the period. ~J.an :[2.2,;, This plan :ie very similar to plan no.I except that it calls for an initial exp~nditure to cover thirteen years. The corresp0nding bond issue is for twenty years. After the first thirteen year issue the issues are for ten years. The object of this is to give a more uniform cost over the period of operation. If at the end of the life of this improvement,which will be in 1943 it is decided that the best policy will be to join the next Co• unty Outfall then small additions can be made to carry until the outfall.is ready. This would mean,however that the city would be paying for the addition for seYen years after i t :ci s obsolete. Plan N ~ Thia plan anticipates that Pasadena will join with the next outfall in !944. Thus the additio~ is until then and the bonds are only for these fourteen years. PLAN NO ,I 3- Additions Population 1940-pepulation 1930: increase to be provided for. 128,000 - 41,000 87,000 41,000 times 55 gives the gal per day to be proTided for,thia is 2, 260, 000 gal/ day. 2.26 times$ 60,000 givee the total cost of the addition,this is $135,000. This is te be paid off in 20 equal,annual indrements. The increase in population between 1940 and 1950 is the same as the increase between 1930 and 1940 so that the following table holds good for both additons. - -t 1929 1939 !35,000 t 6,750 • 13,500 1930 1940 128,250 6,400 13,1,0 19311941 I2I , -500 6,050 12,800 1932 1942 114,750 5,700 12,450 1933 1943 108,000 5,400 12,150 1934 1944 lOI,250 5,050 II,800 1935 1945 94,500 4,720 II,470 1;36 1946 ,. 87,750 4,380 ·11 ,130 1937 1947 81,000 4,050 10,800 1938 1948 74,250 3,710 I0,460 1939 1949 67' 500 3,380 10,130 1940 1950 60,750 3,035 9,785 I94I 1951 54,000 2,700 9,450 1942 1952 47,250 2' 350 9,100 1943 1953 40,500 2,020 8,770 I~44 1954 33,750 I,685 8,435 It45 I955 27,000 I,350 e,100 I946 ... 1956 20,250 I,010 7,760 1947 1957 13,500 675 7,425 1948 1958 6,750 337 Year · "' Amt,nue I9~~••t 5% - Red.ucti(!n 121us IY?,~!r..!s~. -16- 7,087 PLAN J!0,:,11,contl. Populati•en 19(,0~. population 195'01 increase to be prGVi ded for. 215.000 169,000 46,000 46,ooo times 55 givea- 2,~ao.000 gal/day. 2 . j2timee $ 60.000 gives t 152,000 x•ar • .Amt g Due 1949 $ 152, OQO $7,600 $15,200 1950 144,400 7,200 14,800 1951 136,000 6,840 14,440 1952 129,200 6,450 14,050 1953 121,600 6,090 13,690 1954 114,000 5,700 13,300 1955 106,too 5,320 12,920 1956 98,800 4,930 12,520 1957 91,200 4,650 12,160 1958 83,600 4,180 II,780 1959 76,000 3,800 Il,400 1960 68,400 3,400 Il•OOO 1961 60,800 3,040 10,640 1962 53,200 2,660 I0,260 1963 45,600 2,280 9,880 1964 38,000 1,900 9,500 1965 30,400 I,520 9, I20 . 1966 22,800 I,140 8,740 1967 15,200 760 8,360 1968 7,600 380 7,980 1969 --- ----- --- !!LAN NO,_~ Population 1943---140,000 Population 1930--- 87,000 Difference------- 53,000 Coat of addition---$ 175,000 -- 5% . Reduct~2n _p_lus lntere_!!_ Amt Due lnt!_rest 1929 $ 175,000 $8,750 t 17, 500 r930 166,250 8,320 17,070 1931 I57, 500 7,880 16,630 1932 148,750 7,440 16,190 1933 140,000 7,000 15,750 1934 131,250 6,550 I 5, 300 1935 122,500 6,120 14,870 l?36 113,750 5,660 14,400 1937 105,000 5,250 14,000 1938 96,250 4,810 13,560 1939 87,500 4,370 13,120 I940 78,750 3,940 12,690 1941 70,000 3,509 12,250 1942 6I, 250 3,060 lI,810 1943 52,500 2,620 Il,370 1944 43,750 2,200 I 0, 950 1945 35,000 I, 750 10,500 1946 26,250 l, 310 I0,060 1947 17,500 875 9,625 1948 8,750 437 9,180 Year PLAN N0.2 (c~n~l Population- 1953---183,000 Population 1943---140,000 Difference-------- 43,000 Cost of addition---• 142,000 Yea.r __ Amt,f,,Due I942 t 142;000 1943 ---lntereet 2~----ij~duc~ion ~lus l n i l l ~ f 7,100 $ 14,200 134,000 6,740 13,840 1944 127,000 6,440 13,540 1945 120,700 6,030 13,130 1946 113,000 5,660 12,760 i947 106,500 5,320 I2, 420 1948 99,400 4,970 12,070 1948 92,300 4,600 II,700 1950 85 ,·200 4,250 II,250 1951 78,000 3,900 Il,000 1952 71,000 3,550 10,650 1953 • 63,900 3,200 10,300 1954 56,800 2,840 9,940 1955 49,700 2,490 9,590 1956 42,600 2,150 9,250 1957 35,500 I, 770 8,870 1958 28,400 1,420 8,520 1959 21,300 1,065 8,165 1960 14,200 710 7,8!0 1961 7 ,IOO 355 7,455 •I9• PLAN NQ.s,3, Additions uu~ill .~2~1 If at present it should be decided that the best policy to follow would be to make additions which would last un• till 1944 then the costs would be somewhat as shown 1~y the following table. In this I have assumed that it would be pessible to make additions in 1930 which would just be sufficient oo last until 1944. Then in 1944 Pasadena would join with the next County iutfall. As the plant would not be used after this time I have figured the bonds to be retired at that time. By doing it thia way the people of Pasadena will not be paying for the plant after they have quit using it. The estimated population of Pasadena in 1944 is 144,000 The present population ia (from the graph) 67,000. Thus an ir.crease o~ 77,000 persons must be provided for. 77,000 times 55: 4,235,000 gal/day. 4,235 times$ 60,ooos $254,000 Assuming that the sewer was completed and ready for use in 1930,then the bonds would have to be sold and the work carried on in 1929. The $254,000 will be paid o~f in 14 equal annual install• ment s. X!!!:...s_.._,_,______!Jn:.....!.......,•·Du.....,.e......._.____ n...~....e.;;r,...e....,s...t_5,;____R...,e..,d,....\!..,.c.....i ....1 ....gn___.2..J.... I• . e .... re ...s ...w..,__ u _ a _ I _ n . . . . , t. . . 1930 $254,000 $ 12,700 t 30,850 1931 253,850 II,750 29,900 1~32 2IT, 700 IO, 850 29,000 1933 I99,550 9,770 27,920 I934 I8I,400 9,070 27,220 I935 163,250 8,160 26,310 1936 !45',IOO 7,260 25,410 1937 I26,950 6,350 24,500 1938 108,800 5,430 23,580 1939 90,650 4 ,,540 22,690 I940 72,500 3,, 630 21 ,·780 I94I 54,350 2 ,, 72'0 20,870 19~ 36,200 I ,8IO 19,960 I943 18,050 19,052 It is very unlikely that this plan would be used ,first because ef the uncertainty and secondly because it would be rather expensive due to ,:- the short term of the bonds. Neverthe less it is a possibility and will be considered. -21- --------- - .. CHARGES AGAINST ACTIVATED _______ ...........................AND -......PROFIT ON THE ...............,.._.. ... .........SLUDGE ........._. . ... PLANT _, __.... ~ ~ The farm on which the activated sludge plant is lecated is the property 8f the City of Pasadena. All of the profit derived from the plant w0uld go to Pasadena. I have two estimates of the value ef the fann and a fair figure seems to be$ 1,ff0,000 If the farm were s old it is reasonable ta suppose that the money received frQm the sale could be put out ~n interest. A fair rate of interest is 6%. Therefore I have figured this lost interest- as a charge against the plant. In other wards if the City of Pasadena did join the County Outfall Sewer to the ocean then they could sell the farm and receive an interest on the money which they would receive. The farm at present is not making a profit. It is entirely pesaible that when the plant has been in operati0n for a while they will be able to pa.y a profit. I have received an estimate of the probable profit and will give it in the following table. Est.yearly profit Claasifi .£!.._ti _o,..n_ __..4gi;es __ __ _ Qer -~2;:f!. -- Total ·-- ~to!!L- Oranges 75 t IO O $ 7. 500 Beans 295 150 44,200 R(!)ads and Bldgs. 25 Eucalyptus I5 Grain Land 25 Walnuts 60 495 Sewage Di sp 0 sal ...iQ_ Tetal Acres 535 RESUME OF COSTS OF ACTIVATED SLUDGE PLANT AND ADDITIONS Year Plan No.I Total Cast 6.% Interest Valuation 1925 $ 105 mil $70,000 $90,000 $ 160,000 • -- 1930 135 " 85,000 175,000 .13 1935 165 tt 88,ooo " " 178,000 .II 1940 196 It 104,000 ft 194,000 .IO 1945 227 " 86,ooo It 176,000 .077 1950 260 tf I00,000 It 190,000 .073 1955 296 tt 105,000 195,000 .066 1960 325 . " ,05,000 II 195,999 .060 Aa ■ eased Plan No.I Assessed Year Final on fI,5 mil T~tal 6% Interest .Final . Total Cost - Valuation I - - on Farm Teta.l $ 90,000 • Coat per 100 $ .15 Coet per f IOO 160,000 $ .15 180,000 .132 ft 182,000 .II 94,000 ti 184,000 • 094 ft 90,000 " 180,000 .080 260 " 87,000 177,000 .068 1955 296 " 94,000 ff 184,000 .062 1960 325 It IOQ,000 It 190,000 .059 $70,000 1925 $ 105 mil 1930 135 II 90,000 II 1935 165 It 92,000 1940 196 If 1945 227 1950 . __..., .T. Year Aeaeaeed Plan No,3 Valuation Total Cest 65 Interest on Farm Final Total 1925 $ 105 mil $ 70,000 $ 90,000 1930 135 It 102 , 000 tt • 1935 165 II 103,000 ft 193,000 .117 1940 196 II :_103, 000 II 193,000 .099 1J43 21; II 83,000 II 173 , 000 .080 TTT -24- 160,000 192,000 Ceet per 100 t • • 150 .142 COMPARiqQ! .Q:lr_QQ~+_:~HJ!~:m~I!Ng_!.,Iil~L.§bY]2Q~ .4@.+;Ij~RE:§X ---------·---- --- - MAKING THE FAfilf UNNESESSARY ............,.......____.,,_..-.-,. QJ?~ra~!C!,11 Qq!~! Incinerating the sludge----$ 30.00 per million gallons Year G~l.c£t• ... Millions ... , Co a~Lil;! ~ :.g~!.-.- 2im1-!sg Co 8 L $ 30.00 $16,850.0 1910 562.0 1920 1085.0 It 32,600.0 1930 1768.0 II 53,000.0 1940 2;70.0 1950 3420.,0 It 103,000.0 1960 4320.0 It 130,000.0 .. 77,000.0 Taxes The taxes wauld be greatly reduced by doing away with the farm and retaining only that which is taken by the plant praper. Taxes in 1924--•$ 975 Taxes in 1964••• 2,620 Addi ti one The additions Will be made aco0rding to Plan No.2. Incinerating Assessed Cost per iear.__Y!il!l!!Jl..-tQ~.~~u,~g~~-----Ll.QQ__ I925 $ 105 mil $78,000 t .075 1930 135 " 103 , 000 .076 1935 165 " 108,000 .066 1940 196 " 115,000 .059 1945 227 ti 113,000 .050 1950 260 II 114,000 .044 1955 296 " 126,000 .043 1960 325 II 138.000 .043 -25- THE METROPOLITAN OUTFALL SEWER TO THE OCEAN The Los An~lee County Sanitatien District wae formed under the County Sanitation Act which passed the State Legislature in May I92j The ea.id act prevides that,"Said district as created may include either unincarporated territory or both incorporated and unincorperated territery. The incorporated territory included in any euch eanitatien district may include the whole or part of one or more incerporated cities;porvided however~that leee than the whole ef any incarporated city shall not be included in such district except by the unanimous consent of the governing body of euch city;previded,further,that such district formed shall net include the whole or part of any other di strict fanned for similar purpose. 1• t 'The reeeluti&n calling the election shall be published once a 1tU week for three successive weeks in such newspaper having general circulation in the district as the board of directors may t designate No other notice need be given." "If at such election two thirds of tll~ · votes cast are in faver ef incurring the bonded indebte<t:nesa ae proposed,then bonds of the district for the amount stated in the resolution calling the electi0n shall be sold." For any further information ·with regard to this bill see Assembly Bill No.191. The Sanitation District was formed for the purpose of collect• ing and disposing ef the sewage from its entire area. The area tak• en in is shown on the fellowing map. The plan is to collect all the sewage,nriginating within th• District, by m.eans of trunk lines constructed to all centers of populatien. Theae trunk sewera carry the sewage to the OutfallSewer at the southerly boundary of the district.It is a part of the plan -27- to join the County Sanitation District No.2 with the County Sanitation Dietricta Noe.I.3 and 5.Also to this will undeubtedly be added Whittier and possibly a Pasadena District. These districts will then all cooperate in the construction of a common outfall to the ocean.for the disposal ef all the sewage originatigg with in the di strict. Sanitation District No.I includes all the territery between the shoe string strip of the 6ity ef Loa Angeles and the Los Angeles River.frem the City of Vernon to the City of Long Beach. -.J Sanitation District Nn.2 includes the territory extending from the San Gabriel RiY-er on the East to the Los Angeles River and the City of LQe Angeles on the Weet,and form the southerly boundary of the City of Alhambra on the North te and including the communi• ty ef Hynes and Bellflewer on the South. Sa.ni ta.tion District No.3 includes all ef Long Beach. Signal Hill and Virginia City. Sanitation Dietrict No.5 includes all the territory west of the shoe string strip of the City ef L•e Angeles,eaet ef the west c•aet beach cities and includes Inglewood on the North to the ocean on the south. The Whittier Dietrict,includes Whittier and the surreunding vicinity.This is sometimes referred to as District No.6. The Pasadena District includes the City of Pasadena and the surrounding vicinity. If Pasadena. does not join with the present outfall,then a district will probably be formed in thie vicinity which leaves out the City Of Pasadena. The beach cities,Redondo,Hermosa,and Manhattan are not included in this plan because they have already voted bonds and propoee to join th~ "Los Angeles City outfall. The moet adaptable place in ,Loe Angeles County has been eelecte ed for ocean diap&eal. It iii lacated on the rock bound. coast of the San Pedro hills where there is na : poesibility of there ever being any .b athing beaches. The ocean currents are such that they will tent to carry the ecreened sewage outward inte the ocean. As the sewage mixes with the waters of the ocean,it becomes very m much diluted and the free oxygen in the water will gradually change all organic matter and bacteria to stable rratter and will eliminate any possible chance of pelution{so says the County). It is proposed to pase all the sewage thru fine screens;; 1:,o take out all the solid matter before final dispGsal. This plan of sewage disposal will eliminate all local diepas• al within the distriote and it is estimated that it will be more economical. It is estimated that the aystem will be completed and ready for operation in two years,fr•m the date that the bonds are voted. There is only one plan which need interee~ Pasadena and that is Plan No.I. Thia plan is the one which includes Pasadena and Whitt.;. ier. Pasadena is !specially lucky in that she wuuld not have to construct any internal trunk linee,everything would join on at the present activated sludge plant. SHOWING THE PROPOSED PLAN NO.I WHICH INCLUDES PASADENA CITY. PASADENA DST. DIST .NO DIST.NO. 2 ?. ,,i }· I This shows the arrangement and the discharge of the Tarious di atricta. TO THE OCEAN DIST .N0.6 WHITTIER The follewing is the estimated cost of Plan No.I to the various districts. Plan No.:..! __ .................. .__....,.__________ ......____cost ..... of outfall District. Estimated I $ 1,216,.000 2 1 ,,.291, 000 3 I,371,500 5 636,000 Pasadena 2,630,000 Whittier(6} I ,066J 000 Total ··- •- - - - • 8,0219000 The estimated cost of operation ie very low,most of it is for screening and it increases as the flow of sewage increasee. Cost of Operatipn 1926 Thia is aee\.U!led to be a straight line in- 1964 crease. Total coet of outfall to Paeadena District ie $ 2 9 630,000 Aseeeeed valuation of the entire Pasadena District$ 146,167,000 Aaeesaed valuation of the City of Pasadena$ 68,788 9 555 Thia the estimated cost to the preperty ewners of the City of Pasadena to participate in the Proposed County Outfall. The meney is to be raised by voting a bond ieeue. These bonds will be paid off in forty(40} equal annual payments. These bonds will bear an interest rate of 5.5% on the unpaid remainder. The next eheet shows the costs at the end of every five years. Ceata .of MetreJHDli!!.!l.J~utfalJ. It ie planned to sell half the bonds the first year and the other havf the secsnd yaar. There will be no retirement ef bonds the first year. Amount Due Year • 1925 $ Interest 2•~ Reduction Elus Interest 625,000 $ 34,400 $ 65,e50 1926 I, 250,000 68,800 100.050 I927 I,218,000 67,000 98,250 1928 1, I87, 000 65,400 96,550 I929 1,125,000 63,600 94,850 1930 1,093,000 61,200 92,450 1935 968,000 53,300 84,550 1940 813,000 44,700 75,950 1945 615,000 33,800 65,050 1950 500,000 27,500 58,750 195, 344,000 18,900 50,150 1969 187,000 10,300 41,550 1965 31,200 I, 720 32,970 COST CONCLUSIONS From the preoeeding graph it appears evident that the coet of operating the preseat plant ie excessive. The value of the farm which at present is bringing no return on the investment is the faG!tor which runs up the cost. But it is true that the farm has not been in operation very long and it ia almoet impossible to tell in so ehort a time whether or not it ie going to yield a profit. If the farm should yield a profit then it woula probably be beat to keep it and use it for sludge disposal. If however it is not going to yield a profit then it will be cheaper to adopt some other pl~n,that ia either sell t he farm and incinerate the sludge or join the County Outfall. The cheapest method of disposal by using the activated sludge plant is to sell the farm and incinerate the sludge. From the graph it can be seen that the present County Outfall would be cheaper than any of the plans proposed for the activated sludge plant. But if Pasadena will wait until about 1944 when the next outfall will be built, then she will be in a better position to make a decision. At that time they will know whether or not the farm is going to pay a profit. They will then know better whether the disposal of sewage into the ocean is going ot meet with public approval. Aleo they will know whet.h er there are apt to be any complaints against the present plant and theremethods of disposal. It is entirely possible that at some ti me in the near future the effluent from the present plant may become objectionable. If this does happen it may be necessany for Pasadena to provide som:e closed conduit to carry the effluent ,; to the ocean. QON~EijVATION OF WATER With the present demelopment of the country.where large tracte of land are still available sufficiently remote from built up sectiona,where water is such a vital consideration to such land and worth anything from (I) to(5) cents per inch per·t hour for irrigation purposee,and when the problem is becoming mz,re vital with each years growth,to waste sewage w~ter when it is possible to purify it for irrigation purposes in such a manner as to cause no nuisance from odors or endanger public health is a will• ful waste and should not be tolerated. Inthe City of Alhambra,a city of 3,800 acres and largely an orahard city,water sells for $.50 per IOOO cu.ft. Thisis equivalent to a rate of $.03.6 per inch per hour. With a population of 60,000 and a normal sewage f~ow of 50 gallons per capita per day the daily discharge is 3,000,000 gallons or 310 inches. Coneid• er that no storage is provided and that it is possible to sell water only (I2} hours per day and (200) days per year and that such water is worth,for irrigation purposes 3 cents per inch per hour. 310 inches per at 3~$ 9.30 per hour I2 hours at$ 9.30=$ lII.60 200 days at 111.60: $22,320.00 This is equivalent to an investment of$ 446,400@ 5% . The only thing against this is that it may be hard to dispose of the efflient,or waste water. Another plan for the conservation of the effluent ia te pump it up back of Devils Gate Dam and let sink into the natural reservoir. This plan might well be feasible from a financial stand• point and it seems to meet the approval of the State Board of~Health,for in his letter states tha~ he sees no objection to it . .. :£· CONSERVATION.OF WAT~R (Cont) It has 1:,been aai d that a municipality shuuld no t a l low commercialism to enter into its affairs. In seme cases this may be true,but I see n0 reason why we should waste so valuable an asset when such asset can be utilized without interfeering with the rights of others. -36- The discharge of the Loe Angeles sewer into the ocean at Hyperion caused a nuisance before the present sewer was constructed. Thie was chiefly due to to the sewage litter which ie noticeable along the beach and in the adjacent water for a mile or more in either direction,particu.la.rl; to the south. The effect of such pollution varied with the wind and tide both ae to extent to which it was noticeable at any one place, and the distance from the Hyperion pier to which the sewage was carried. For some distance from the Hyperion Pier there was a sewage field,varying in extent within which the sewage was insufficiently mixed with sea water to prevent detection as to its prigin. Some times the odors were of an oily nature but in hot weather the odors were very offensive and suggestive of sewage. Bacteria analysis of the surf water showed that bathing at Hyperion would be attended with some risk if the bathers should have swallowed some of the water. The same is said to be true of a number of other places along the beach far removed from the Hyperion outfall.Thie shows the necessity.in the interest of clean safe conditions for bathers, of rraterially improving the sewage dis posal arrangernenta,not only at Hyperion but at numerous other µxx places a long the coast where local outfalls discharge. It is true that patrone of the beaches ar~annoyed be black, oily rraeees which are not however the result of sewage disposal but are washed ashore from submerged oil and. asphaltum deposits, such as are shown on the u.s. Coaet Survey chart opposite Redondo. There are also some oily substances diacharged into the ocean from the oil works at El Segundo. -37- CALIFORlHA STATE BOARD OF HEALTH Sacramento Bureau of Sanitary "Engineering. C. G. GILLESPIE, Director Berkeley, California, October 27, 1924. Mr. Wm. C. Rowse, City Hall, Pasadena, Calif. Dear Sir: I shall attempt to answer the questions you have aslrnd with respect to your activated sludge plant, as fully as I a~ able. Question (1). "In your opinion woulcl it be entirely satisfactory from a standpoint of health and public nuisance, to continue to discharge effluent from our present activated sludge plant into the Rio Hondo, provided said effluent was of a quality satisfactory to the State Board of Heal th''. ~he State Board of Heal th would not endorse or allow the emptying of sewage effluent into the Rio Hondo if it menaced health or created a nuisance. In my opinion it is easily feasible to satisfy these require- ments by treatment using the activated sludge method, folla::ed by sand filtration or chlorination. of this performance. I would expect your present plant to be capable I would at this point make a generalization a.--pplicable to most of the opinions you are seek ing, that I regard the activated sludge process as a very efficient one for producing a clear, stable (i.e., odorless) effluent of relatively low bacterial content, but tr.at it requires the programing of construction to k0;ep ahead of the nee ds, the use of a certain degree of skill, easily attainable, in operation, the avoidance of penny-wise ' -37- policies in operation and, ,•there an effluent of the safety of driti!{:ing \Va ter is required, it requires chlorination or sand filtration of the effluent. Also, that it requires a certain isolation to protect against plant nuisance and where area for wet sludge disposal is a difficult item, it requires sludge dehydrating and drying devices. isolation is to be sought whenever possible. Experience as to Our observations at Lodi and Folsom show the very modest isolation of 500 feet to be sufficient there. Your best guide is your o·wn experience. Question (2). urs our present activated sludge plant capable of purifying the effluent to a quality satisfactory to the State Board of Health?" I would anticipate that you are probably producing an effluent satisfactory to us, but have no tests upon which to base this opinion. Quest ion (3). "Do you believe that there is any probability tr.iat a sewer wi 11 have to be construe ted to carry said effluent to the ocean?" I can anticipate no requirements from this Board, or any from the standpoint. of health and decency, which need compel i,tollt' carrying this effluent to the ocean. In my opinion all reasonable requirements can be easily met by proper design and operation of the treatment works themselves. Question (4). "Nould you approve of the practice, from a health standpoint, of pu."Tlping this effluent back of Devil'$ Gate Dam, allowing it to drain into the underground basins from which Pasadena pumps its water supply for domestic use? 11 Without regard to- prejudice and sentiment, and considered from the standpoint of no unwholesorre or unhealthful effect on your water supply, I see no objection to this disposal, but would expect it would be prudent to first pass the effluent through a sand filter. Well water supplies are -39being pre served in Germany by the similar expedient •of spreading storm drain water upon areas to be saturated for well water supply purposes. (See later letter of October 30, 1924) Question (5). "Nould you approve of the practice of using said effluent for irrigation of either parks or crops?'' The effluent of your plant is well suited to irrigation, without nuisance. I should consider it advisable to chlorinate it prior to use on lawns, but not on shrubs, and on table vegetables. Question (6). 0 Is ''wet sludge" free from harmful bacteria?" In nw opinion wet sludge is to be looked upon as highly dangerous unless stored for three or four weeks. Question (7). 0 Is 'dry sludge' free from harmful bacteria? percentage of water in dry sludge? What If not, does said sludge become harmful ,.vhen wet again?" I believe dry sludge is reasonably free of disease germs an:i will remain so. ~iuestion ( 8). "Should the present practice of spreading ;'wet sludge" on the Pasadena Sewer Farm be continued or discontinued?" I cannot answer this question since I do not know the cro1)s upon which it is used or nearness to residences. Question (9). "If the sludge were properly dried cruld it be dispos- ed of anywhere, either sellilig as fertilizer or dumping as a fill for low ground? In ot1ier words, could the activated sludge ~lant be operated witToiout the farm?" Such dry sludge could, in my opinion, be handled with impunity. I would regard it as necessary to retain ellough land around the \vorks to keep -40you free of odor co mp lain ts from high grade residences, assuming that the surplus land were disposed of for th9.t purpose. Question ( 10}. See Question (1). "What are your views as to catering to public sentiment?'' I believe that sanitary engineering should be availed of whenever economy results, that health should be protected and that nuisance and property damage should be avoided. Beyond th9.t, the expenditure of sums simply to satisfy sentiment is one mich I believe can only be settled by the people ·who J?8¥ the bills, with a full and fair understanding of all the facts and the realization that what they are paying for is satisfaction to .s entiment. Question (11). "From your information, what figures should be used in calculating the following: (a) Average flow of sewage in gallonp per capita per day. ( I used 55) (b) Maxinrum flow of sewage in gallons per capita per day. ( I used Mr. Warren's figure of 80) (c) Cost of operation of activated sludge plant in dollars per million gallons, without drying sludge. (I used $14.00) (d) Cost of operation of activated sludge plant in dollars per million gallons, including drJ,ting the sludge. (I used $30.00) (el Cost of additions in dollars per million gallons per day. (I used $60,000l (al This figure seems lo.v, as judged by measurements of sewage flow elsewrere, but should of course be predicated on looal measurements or analysis of local factors. (bl This figure seems lon but appears consistent as compared with the figure in Q,u estion (a). -41- (cl '11his figu.re lookE reasonable. (d) This figure looks reasonable. (el This figure looks reasonable. Very truly yours, C. G. GILLESPIE DIRECTOR CGG T C.ALIFCRHIA STATE BO.ARD OF HEA.1'111:I SACM.J\lENTO Bureau of Sanitary Engineering C. G. GILLESPIE, DIRECTOR Berkeley, California. October ro, 1924. Mr. Nm . C. Rowse, City Hall, Pasadena, Calif. Dear Sir: I sent to Mr. Goudey a copy of my letter to you and he corrects me in two particulars. It seems I misunderstood the portent of Question (4). I under stood the plan was to dispose of the effluent u:pon the sand deposits above Devil's Gate reservoir. Mr. Gou.dey understands the inquiry to refer to emptying the sewage directly into t he reservoir and calls attention to at least one objection, namely, the setting up of a.:lgae growths in the reservoi r if that is done; al so that the indica tioilils are that t his water passes rapidly fram the reservoir into t he filter gallery. I therefore ·vis:h to correct any misim:pression I have g iven am. reiterate t hat I would have no ob jection to running the effluent from the activated sludge plant through a sand filter B.."1d then upon the sand depo sits above t h e rese r voir, such that t he sewage would finally gravitate into the underground waters. In further co mment on Questi on (11), r.1r . Goudey calls attention to the fact that the figures for t he main outfalls should all~v for co nsiderable infiltration and in all probabili ty the maximum rate shou ld be higher t 11an quot ed. Very truly yours, C. G. GILLES1?IE--DIR ECTOR CGC T -42- THE HUMAN ELEMENT IN OPERATION In the practical operation of a sewage system such ae an activated sludge plant it is as a general rule very difficult to get men of high order as superintendente. The salarys of su~h a position are generally not very high and one with training or experience is hard to get and hold. Thie means that at some time the operator is apt to let go an effluent which is very putricible and offensive. Such a practice as this 1s beund to lead to trouble sooner or later for the people below the plant are going to complain. I do not know whether this has hpppned at Paeadema~ plant yet or not but it is liable to happen and is one of the objections to euch a system. POPULAR SENTIMENT Popular eentiment at the present time seems to be opposed to disposal into the ocean,becauee of the nuisance to beachee. Thi8 opinion hae been created,no doubt,by the condition of the former Loe Angelee outfall. This condition hae been remedied now and it remains to be seen whether or not public sentiment will change. GENERAL CONCLUSIONS In general conclusions I would say that the best plan would be to wait until 1930 when additions will have to be made and then to decide whether or not to keep the farm. At that time the City of Pasadena can either make addititon until 1944 or they can make longer ones. At that time they will know beeter the ~0ssibilities of the plants paying an income. They ~ill also know the efficienc y of activated eludge diepoeal and the popular sentiment with regard to diepoeal in the ocean. BIBLIOGRAPHY Mr.Ro_wee City of Paeadena, Report along eimilar lines. Sewer Syeteme and Sewage Diepeeal Califernia State Board of Health. Report of Special Sewage Diapoeal C•mmieeion George W.Fuller George C.Whipple William Mulholland Aeaembly Bill No.I9I. Taxpayers Guide fo~ 1923. Sewage Diepoeal Geerge W.Fuller Sewerage and Sewage Diepoeal Harold E.Babbitt. Mr.A.K.Warren County Sanitatian Engineer