| | | ut DECATUR; ILLINOIS SEWAGE IeTSPOSAL. PROBLEM AND A SOLUTION THESIS FOR DEGRFEF OF C. E, FLETCHER AMOS GOULD SFG. Be NS NE Ae al el — 7 THESIS (3 (eu ie DECATUR, ILLINOIS SEWAGE DISPOSAL PROBLEM AND A SOLUTION. THESIS for Degree of C. E. FLETCHER AMOS GOULD. 1914 —* aes The object sought in tnis thesis is a general method of solution for the very complex problem of dispos- ing of tne sewage of Decatur, Illinois, in such a manner that it wilt in no way be a public nuisance or a menace to public health. The detailed design is not sought and, in fact, could not be attempted with the limited data ob- tainabLle at the present time. Already there has been spent thousands of dollars in obtaining the present available data and it is estimated tnat it will cost not Less than ten thousand dollars to obtain the lacking data which will be necessary before tne detailed design can oe undertaxen, Decatur, a city of about thirty-tive tnousand innubitants, ties in Macon County, in about tne central part of the State of Iistinois, in the midst of a very fer- tite, farming community, and is one of Iliinois' most rapidsy growing cities, The Sangamon Hiver, which passes through Decatur, serves both as a source of water supply and, at present, as tne channet for conveying Decatur's sewage. In deating with this subject, I wili present my discussion under the following heads: J Historical Sketch, Visible Evidences of Poitlution, Expianation of Plates and Discussion of the Facts Brought out by Data Con- tained Tnerein, Summary of Facts Brought out from Fore- going Data, A Solution of the Problem. To aid in tne explanation or the provlem, a con- siderabie part of the data is given in the form of tabies, 96423 Charts, and maps, inserted in the back portion of the bpooK, Historical Sketch In the Latter eighties and tne early nineties tne citizens of Decatur, realizing tne necessity for more heattnfuL and sanitary conditions, and Knowing tnat tnese conditions, sould be obtained only by carrying away the stagnant,,surplus surface water and the city sewage, which untit that time had been carted away in wagons or allowed to run off in open streams, engaged engineers to make the surveys and design a complete combined system of sewers, UnLtike most cities the size of Decatur at that time, the people of this city realizea the need of prover drainage as well as sanitary sewage disposal and Looked into the future far enough to see that it would pe economy to put in the combined system in preference to the separate system, in spite of the fact that the first cost of the combined system was far in excess of the cost of a separate system of sanitary sewers, Little aid they realize that they were making a gross error, which many other cities avoided, by no good judgement of their own, for it never occurred to them that the quantity and quality of Decatur's sewage would increase to the point where it would unduly poLtute the Sangamon River. In the Summer of eighteen hundred ninety the first construction was commenced by building a portion of the Broadway Main Sewer, which is a six foot circular sewer, ana the Union Street sewer, 2n egg shaved sewer (356 x 54 inches), from the corner of west Decatur and Church Streets far north into what was then the Northwest portion of tne city. Neither of these sewers were built to the river, but emptied into open ditches which ran some dis tance to tne same, Later they were extended to the river, tne Union Street Sewer in eighteen hundred ninety two and three and the Broadway in eighteen hundred ninety six, In eighteen ninety eight the Oakland Avenue Sewer, a five foot circular sewer and the shortest one in the system, was constructed. Nothing more was done ex- cept building taterais to these already constructed mains until ten years Later when the Seventh Ward Sewer was built, This is a five foot circular sewer and runs from a point west of the city well over to the north central part, cover- ing an immense amount of territory for so small a sewer, The cost of these trunk sewers alone, to say nothing of the extensions and laterals is as rollows: Broadway Trunk.....cecesee $25,400.00 Union Street Trunk...... 41,551.50 Oakland Avenue " ..ece- 1,840.95 Seventh Ward Trunk......_ 75,9924 TOCEL ec cccccccccccccsee oGl47, 884,59 It was not long, however, after the first con- structions were completed before some comolaints were heard, These first came from the fishermen, who claimed that the fish caught way down the stream tasted of the wastes from the gas works which were dumped into the sewers, These com pLaints did not amount to much, being orly occasional at first and, in fact, not becoming very consistent or ver- sistent until after tne opening of the Staley Starch Fact- ory about four years ago. The down stream farmers soon became very much agitated and on August first, nineteen hundred tweitve an indictment was secured against the city, tne complaint being that, "Decatur caused fiiltn in the Sangamon River and rendered it unwholesome and impure," At this time the city being granted a suspen- Sion of LegaL action penzing an attempt on their part to correct tne difficulty, asked tne State Water Survey to herp them, In the meantime, the farmers becoming pro- voxed at the prolonged deliberation of tne city, which seemed to tnem unnecessary, took up the matter with the Rivers and Lakes Commission, which commission made in- vestigation and, finding that the city was doing its best, counseled patience, At the present time, tne farmers are abiding by this counsel and the State Water Survey has just recently made its report, stating that tre river is badly polluted due to Decatur sewage and recommending that tne city taxe steps to purify the same, Visible Evidences of Poltution. Plate 2 is a map showing the various points aLong the river where samples of the water for analysis were taken and where stream gagings were made, These same points or stations show certain visible evidences of poll- ution which enable one, without further investigation, to see tnat there is present a very great nuisance if nothing more@. At Station Six, which lies just below the water works dam the water has every aprearance of being normal surface water. Although tnere are points farther up strezm wnere the river is nolluted it has become self-purified by tne time it reaches the Decatur intake, Station Seven a couple hundred feet below station six, is below the outlet of Broadway Sewer, tne discharge from which completely changes the water and gives the river tne appearance, during the stages of low water, of a Large open sewer, The sewer discharges into a small cove, which is completely filled with the four smelling sewage, which overflows from this into the river, The sewage is of more than average strength, containing wastes from the gas works and starch factory, and giving off a very strong odor, The gas works waste forms an oily film on the surface, several hundred feet farther down is tne Union Street Sewer outlet, which opens into an open ditch some thousund feet Long tnru which the sewage flows to the river. White the discharge from this sewer is in itself sufficient to cause trouble the change which it makes in the river is scarcely noticeable, due to the much greater quantity and worse condition of the Broadway Sewer. The river continues very filthy between this point and the outlet of the Oakland Avenue Sewer, and bubble of gas rising indicate that active putrefaction is taking piace, while the bed of the river is covered with a heavy buack Sludge, The Oakland Avenue outlet is about seven eights of a mile beLow the Broadway Outlet, and like the Union Street Sewer, does not make much impression on the aLready grossly poliuted river, At this point tnere is a highway running near the river, and a new residence addition is now being built up here, both of which will be greatly damaged by this pollution. Station Hight Lies just above the Seventh Ward Sewer outlet, and at this point the sludge is not so heavy because of tne septic action which has taken place in the siowly roving stream, At this station the river has a biack appearance, much in contrast to the appearance at station nine which Lies two hundred feet below the Seventh Ward out- let, where the fresh, light colored sewage enters, Occupants of a residence a quarter of a mile south complain of the awful odors from the river. At this point heavy, dark gray, siimy growths begin to appear. At Station Ten one and one half miles farther down, the river is still black and has a strong odor although this point is just below the entrance of a small creek into the river, which must help dilute the sewage. Complaints come from a residence a half mile away from tne river at this point, At the next station, number eleven, four miles from the Broadway outlet, the river is stiLi1 dark colored and undergoing fermentation and slimy deposits also appear, Two miles beiow this station, at Jacobs! farm, cattle pas- turing along banks drink tne water an: become sick and die, Here the stream still has tne gray color of polluted water 7 without sufficient oxygen; the odor is strong, and there is still a tnin deposit of sludge on the bed. Station Twelve, seven miles below the Broadway Outset, shows the water polluted and large floating masses of greenish black scum are present, At Station Thirteen, Scroggin's Bridge, nine mites below Hroadway Outlet, the water begins to show a change, There is still some sludge on the bottom, but the wnite starch factory waste is tne main substance present. There is some odor, At Station Fourteen, which is about fifteen mises below Station Six the condition appears about the same as at Station Thirteen, Twenty-two miles down stream, at Station Fifteen, during the time of Low water the river appears perfectly clear and contains small fish altnough it is said tnut at tisies when the water is higher, sludge is brought down, bad odors are noticeable and often times the fish die. This shows that while the water is low the slowly moving stream has time to purify itself, but upon a rise of water the current becomes more swift and quantities of unpurified sewage are brought down even to this point. Explanation of riates and Discussion of Facts brought out by Data Contain- e herein. The data available for use in this discussion inciudes a map of Decatur snowing the present sewer systen, water analyses and stream measurements made by the State Water Survey and others,at and below Decatur, sewage anal- yses and gagings, and other maps and charts which will be found valuable. PLATE 1 shows the complete system of combined sewers as they now stand in Decatur, This system is div- ided into four sections known as follows:- Broadway Sewer, Union Street Sewer, Oakland Avenue Sewer, and Seventh Ward Sewer, Each section is marked on the map ina different coLor of ink, These sewers, which were designed to serve as sanitary and storm sewers, have already become too smaiit, and at times of heavy rainfall and runeoeff the. sewage bubbles out of the mansholes far back on the trunk lines of eacn of the three larger sections, PLATE 2, as previously explained, is a map show- ing the stations or points on the river where samples of water were obtained for analysis and also wnere tne stream gagings were made, and in general outlines the points of interest in this discussion, PLATE 3 is composed of two taovles giving the resuits of anatysis of the water at difrerent points and on different dates. These analyses show turvidity, color, totaL residue, chiorine, alkalinity, non-carbonate hardness, totai organic nitrogen, free ammonia, albuminoid ammonia, nitrites, nitrates, stability, oxygen consumed, dissolved oxygen, and bacterial content. Tne TURBIDITY, TOTAL RESIDUE, and ALKALINITY show very Littie. The COLOR does not show much beyond being of assistance in visual determination. The nigh CHLORINE shows very clearly the influence of sewage and,to some ex- tent, the dilution available and also suggests the ferment- ing condition of the sludge on the bed,causing it to rise and be disproportionately distributed down stream, In time of tow water the NON-CARBONATE HARDNESS seems to be increas= ed bpeLow Decatur showing the influence of pickling liquors used in some of the metas working estabLishments of Decatur, The TOTAL ORGANIC NITROGEN in such large quantities demon- strates tnat the siudge is in a state of active fermentation. The FREE and ALBUMINOID AMMONIA and OXYGEN CONSUMED show practicasy the same thing as the organic nitrogen, while in addition the free ammonia indicates tne staLeness of the sewage and occurs in greatest quantities at time of low water, Tne NITRITES and NITRATES both appear to reach a maximum together, indicating that oxidation is not Keepng pace with nitrification, although the nitrates are not entireiy exciuded as is the case in more intensive puri- fication works devending on anaerobic bacteria, The REL- ATIVE STABILITY shows a decrease below Decatur. The abnorm- alt height of DISSOLVED OXYGEN at stations fourteen and fifteen is probably due to the stimulus given to plant life, which gives off oxygen, by the products of decom- position of the sewage pollution above, The determination of BACTERIAL CONTENT seems to be the most consistent evidence of pollution. It shows a strixing increase at every point where sewage enters the stream and traces the pollution farther down the stream than does any other determination. The quantity of bac- é teria of intestinal origin is large just below sewer out- lets but practically disa-“ears at from seven to nine nites beLow Decatur. In general tne analytical data from the water of the Sangamon River shows pollution so great that much less sewage would probably pollute the stream just as badiy, because the stream flow is so small tnat it would not even dilute a much less quantity. However, the in- creased discharge of sewage would probably extend the nol- lution fartner down stream by increasing the velocity of tne current, PLATE 4 contains the analysis of the Decatur sewage, Samples were taken at half hour intervais from five thirty A. Me. to ten ¥. NM. Tne weighted samples wnich were taken from each sewer were obtained as follows: Each harf hour a sanple was taken and at the same time the firow was gaged, A portion of each sample, in vroportion to the flow as gaged at the time the sample was taken, . was put into a vessel and all mixed together. From this mixture a sample was taken and used as the weighted sample of that sewer, Tne analysis shows the Broadway sewage the strongest, with the Oakland Avenue sewage only a little vehind, the Union Street sewage some weaxer, and the Seventh Ward quite dilute, due to its domestic character, The average for the city seems to be above normal strength. The total residue on evaporation is above normal, the volatile solids twice normal, probably due to starch factory westes of the Broadway Sewer, Tne Union and Oakiand Sewers also show presence of some manufacturing wastes. still the weighted average nitrogen content is below normal, the amount of free ammonia, nitrites, and nitrates, showing a comparatively fresh sewage, PLATE § gives the measurement of sewage dis- charge and shows that the sewers in the order of their quantity of discnarge are: Broadway, Union Street, Seventh Ward, and Oakland Avenue, PLATE 6 is a diagram showing the discharge of the sewers based upon the measurements of plate five. PLATE 7 is a summary of information contained in plate five, PLATE 8 is a table showing dilution available for sewage disposal at Decatur. PLATE 9 gives the results of stream gaging just below the waterworks dam and indicates the small frow during the Low water period, PLATES 10 and 11 show rainfall and run-off at points above and below Decatur and are the basis for the caiculations of the same for Decatur, as shown in diagram of plate 12, PLATE 12, This diagram shows, as brought out by the red Line drawn, that for a large portion of the L2 year, the run-off is not sufficient with the present popuration. This proportion of the year when run-off is not sufficient will increase with increased population, as shown in diagram for nineteen hundred twenty three and nineteen hundred tnirty three, as the run-off is not expected to incresse, These are taken from the United ctates GeolLogieal Survey records, PLATE 13 gives rainfall in inches at Spring- fierd, also taken from U. S. G. S. records, PLATE 14 is ea diagram showing the past and estimated future population and water consumption of Decatur, PLATE 15 shows, in the form of a diagran, the quantities of diluting water required for various quantities of stomm sewage to purify to a non-putrescible state, and based on a minimum necessary diLution for sewage of 5 cu. ft. per thousand persons, The absdciss8s represent the numper of times dry weather flow and the ordinates represent the amount of dituting water necessary for the particular volume. It wists be noticed that it is comparatively large at first, as the proportion of sewage to storm water is large, but at twenty-two times dry weatner flow there is no dituting water needed, Summary of Facts Brought Out from Foregoing Data, The facts brought out from the foregoing data may be summarized as follows: 13 FIRST. The Sangamon River is grossly polluted by Decatur sewage for a distance of ten to twenty miles, SECOND. This pollution forma a public nuisance and is probably a menace to public health and must be removed to the extent of bringing the sewage to a non- putrescible state and reasonably free from suspended matter, THIRD, The present sewage system is a com- bined system which, at the present time, is not Large enough to take care of the storm flow. FOURTH. The Decatur sewage is stronger than norma sewage from a combined system of sewers, but is comparatively fresh, It has at present a daily volume of 3,000,000 gal. per twenty-four hours and an estimated probable volume of 4,4C0,000 gal. per 24 hours. FIFTH. The stream flow of the Sangamon River is not sufficient to dilute the sewage during a great portion of the year, being likely to be Less than 50 cu. ft. per second and sometimes less than taken out for water supply. SIXTH, As economical a method as is practical, witnout sacrificing efficiency, must be adopted, as the city is in no condition financially to assume an unnecess- ary expense, SEVENTH. The starch factory and gas works wastes increase the strength of the sewage very matere- laity and wiil make it much more difticult of disposal. The Starch Factory wastes are from six to eight times i4 normal strength and have a volume of 1,000,000 gal. per twenty-four hours and will probably double, The Gas Works waste hes volume of 10,000 gal. per twenty-four hours. EIGHTH, The sewage is discharged from four different outlets necessitating an intercepting sewer to convey sewage to the site of the treatment plant, Solution of Problem, Degree of Purification Necessary, There have always been two conflicting con- ceptions, botn extreme, of the function of a stream, First, that of those people who advocate keeping the streams completely pure so that they may be available for water supply without any treatment. Second, that of those wno feel that ail a stream is intended for is to drain off wastes. It is evident that neither is correct, and we must strike an average, by which any given stream may meet the most important need of the community as a wnoLe, This requires that a water supply should always ve purified; a fact which is true regardiess of how pure &® stream appears, On the other nand, drainage should not be of such a character as to be objectionable to the public, Not only should the stream not give off bad odors and distribute disease, but its appearance should be such as not to be repulsive to the public eye, and furthere- more, streams which are used for recreation, as is the C1 Sangamon, shouid be pure enough that people woud not hesitate to bathe in them. The Sangamon is a river which is not only used for water supply by cities below Decatur, but which runs through quite a thickly populated country and is used to a considerable degree for recreation purposes in some piaces, and would ve in others if it were not for the possution. Therefore, it should be kept at a sufficient degree of purity tnat it can be utilized to the greates. Gegree of its usefulness by the different interests. This wousd not necessitate absolute purity, but would require tne removat of all matter in suspension, and the bringing of the Liquid effluent to a non-putrescible state, Possible Methods of Treatment Modern Sanitary Science affords several pos- sibtse methods of treatment wnich are considered quite reiiable, One of these, or a combiuation of two or more,Wili usually be found satisfactory for most any probsem or condition. The most important and reliable of these inciude the following: 1. Chemical precipitation. 2. Intermittent Sand Fi.ters. 5. Contact Beds, 4. Sprinxiing Filters. 5. Settling ‘ranks. 6. Septic Tanks of Imhoff type. 7. HypochLoride treatment for sterilization. 8, screening. vhemica. precipitation gives quite efficient c1urification, but tne quality of the effluent compared to tnat of some other methods does not warrant its use for ordinary sewage, because of the greater cost of operation. As we are 1ooking for economy as well as efficiency this method is out of the question. The Intermittent Sand Filter as a final treatment, with good management and under favorable cone ditions, gives the best quality of effluent to be obe tained for a given cost. However, it is very expensive of construction where the sam has to be hauled any great distance and, moreover, it requires a consider-= abse area of ground. In this locality the expense of construction for this form of treatment would make it prohibitory. | contact beds give a fair effluent and are used to a considerable extent for small plants, but the action is very slow and they are, therefore, very exe pensive for Large plants. The size of the Decatur problem is too Large for a consideration of this method. sprinkLing Filters remove from 70 to 90 per cent. of bacteria from the effluent, and, when used with fairiy course material in the beds, Mmve a very rapid action. While not giving the highest degree of puri- fication, tney reduce tne non-settling colloidal and mart Email ial oe ro eae dissolved organic matters to a point where the effluent wilt no Longer putrify or ae : | ad " a = \ ye ae Lads mame ary hy} . " FF Ned debs iS. | SR Me en) rz. PHY ae < . Average caLyi Le — i Piate 5 . Measurement of Sewer Discharge at Dacatur. Dec. Z/, PPT TLS tat TL LL ol lar 4/28 (0:00 Average ch) are Plate 7. . Summary of cy ET Flow Measuremen on Dec.24, /9/2. cat a LA pd ah by Ay. saith Baie aa t (nr Cu. ft. per |in gat. per . pts are 1 Pe er 4 seated £2. ele WE Err rT) re aa Union St) 0.9787 FY0, 000)| 37 ol LTE LL Ma 12 ie a Co ee ee 7th Ward | 0.248 YA) | LT Pe ae / Plate 8. ey; Ailution availeble for YT To FULT TILT afl Decalur. Co ALE ments trade by State Walser Sur vey) Discharge waa i Sec. Ft. Sec. |Gal per | persooo ae pero RL Nov. 30, /9/2 89.5 |F§8,000,000 Fn Dee. 20,/9/2 | 669 73,300,000) /.9/ | Suly LAL mar eA FERAL Be: | 4ug-F-7, 19/3 0./8 ke Cee) 005 ee AY ee 4/8,000 my) # Present pobulatiors of Decatur 395,000. —) lad Tae «Stream Gagings of Sangamon River haa lee 1a ae ale ae eee ae EEC AES 89.5 |58,000,000 BPE CICHs a rote el® ne Wena 1913 > eee Len 1 214) eee Ares 0./8| /14000 | Sept.25/9/3 | 2.0/ | 1,4/8,000 oe ae ena . 7 a " oH a. ee: ee ee ee is Peet a ons 2) os : a eg On | 6! 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