THESIS AN INVESTIGATION OF THE OTSEGO SEWER SYSTEM C. W. BARBOUR. & L. E. BELKNAP. i915 = FHESIS © This thesis was contributed by C.W « Larbour the denartment stamp, to replace the original which was destroyed in the fire of | under the date indicated by | larch 5, 1916. Sarees TE ey re Oe. An Investigation of The Otsego Sewer System A Thesis Submitted to The Faculty of MICHIGAN AGRICULTURAL COLLEGE By C. ¥._Baybour L. EB. Belkmap Candidates for the Degree of Bachelor of Science June, 1915. THESIQ AN IBVASTIGATION OF THs Soa CYT G8 OT, oa, BIC Ts He ~Wary sever syuten is ast to hive iauny defects due to feulty design, cenetruction, or a combinatios of tis two, end 2180 pe@rlii:ups due to the ruinid rosth of the city. And inassuch as the vtsego system was civing »oor satisfaction, and seemed to oe almost a fnilure, tue tu ti. -~bove reacons, an} aleo oe@cuuge of vary ealical ecuion::ag6 #ifen ware m.de in the construction fro. the ori..inal pil«ns, .9 chose tris sudject as a thesis, for t:9 9urdv:i@ of orovosing imoroeve- ants tor the ecistin, systea. And 23 t..is system only covers avout ona-half of tie city aii is running sixty-four o7rcaht full now, ve proooge to desim a now aysten, comlete with now trunk ling ani ga tio task for tiis vortion of we city not alrecdy sux, lied with a seser system. s@ side a aouoglete survey of tine existinz system, °3 well as taking a cozdlete sat of levels over the :raa to be covyores by tne orconoual sewer. Jas LON MO Toe ar CACHE ak OS CCRTeTIGN. vtvcegoe is a vill:u.e of avout three thousand vovulition, maig situ ted avout fiftean miles north of Falst:nzoo, in the County of Allecjin. Tne Le. i. 2 MH. Ge Rallway connects ti: Willa-e with Grind "%itfi8 on the north and Falam:zoo on the . south. Running taroucsn the ewiter of the villa.‘e is the } alsusazoo River, wiiieh also floas tiroush the canter of Allegan tralve miles below. Tne resident aUstrict is soreaid out on Both sides 93842 oJ= of the river, with tne liurgest portion veing on the vouth side. Qn the north side, the residences follow only one street which rums virallel to the river, :nd ore of the ohe:oer class tenenent houses. ‘The rnilroad is on this side alse the total of six lurge oaper mills, a moe factory ani a chair factory. These mills ani factories hive their ori- vate sever Systems, az hve also a tew of the houses. The stores and the better class tenement houses ure loc:ted on the south side, extending aocout a half of a mile froin the river andi avout three qu:rtere of a mile alonz the river. This portion of tne vwillacs is aractically level ground, tne seearter contour not varying over thres feet. ‘he original Plan wis to cover tis side of the river with one system, hav- ing the trunk line on the west side of tom. However, upon investi,;ation, it seansdt» be oracticable, frow doth a auni- tary and economical standsoint, to cover the eastern portion, which has not teen dined aa yet, witn a sanarate sysaten. The Palamagoo ‘iiver affords a vary acceptable outlet for the senige at theoresant time, HMNowsvayr, with the vrecoant advance aloniz the lines of smitation £% will only be a short time before the authorities will take steps to solve the problem in a sciatific, i393 well as economic mannew. They are becoming aroused ag to the value of maintaining stre:.mse in a pure condition, veczuge ever if not used for drinking purposes, it iv usually used for donmgstic purnoses, snd then 4% also is of creatvalue to nove the water pure, 90 28 to Dre- s?rve fish life, nt in order to hive the ice pure as possible -3- and finally because on the broad ground, that water courses belong to the country as a whole, and must be kept pure for the sake of succeeding generations, not spoiled for them on account of the selfishness of a few at the present time. It will be only a few years before the laws of Michigan will compel. the city to put in some kind of disposal, or purify- ing plant, because the sewage is certainly a nuisance to the public. In case Septic tanks are installed, two systems could be used, one with each trunk line PRESENT SYSTEM. The present sewerage system in Otsego was installed between the year 1912 and the present time, a little being added each year. Up to that time,the only sewers in use were a few private ones. The system,as originally designed, had one trunk line upon North street, emptying directly in the Kala- mazoo River. From this trunk line, parallel laterals were to be placed upon each east and west street, running the mtire length of the street, or as far as needed. During the process of construction, many changes were made from the original plans, the location of some of the laterals being changed by the village authorities, for the purpose of making a cheaper system, and the efticienoy of the system thereby being lessened; che elevations and grades were changed during the process of construction by the contractor. This change in elevation primarily started in the trunk line between Orleans and Allegan streets, where quick-sand, or at least bad water sand, was encountered. The contractor speng twenty-two days trying to lay tile in this material, cut was unable to make any progress at the specified eleva- tion, and as he had been hired to do the @mgineering work as well as the construction, there was nothing to prevent him from raising the sewer, and in order to clesr himself, this is what was done. This mide 1t necessary to raise all the laterals above this point, and in order to have the most rencte parts of the laterals somewhere near ths spesi- fied elevations, the grades hod to be greatly reduced. The original plan ws to place siphon flushing tanks at the ends of each lateral, but this plan was never carried out. However, the Framklin street sewer is flushed by a two ineh pore stream, which is turned in from the county drain upon Morrell street. Instead of running laterals eastward from North to the Plainwell Road on F.rmer, Yrankiin, korrell and Hammend, as the original design called for, they have enly been run to Fair on Allegan, the whole length of Branklin, and up as far as Fair on Hammond. On Orleans and Morrell, two of the vrincipal resident streets, short later- als have been run for the length of a block in a few places, then connecting to the lenger lsterals by short lines up to north and south streets. This arrangement, of course, neces- sitates a very snnll amount of sewage flow in ech one, snd also seversl dead ends, wzhich we factors to be avoided if possible, 3nj sould hive been if the original plan h-d been followéd. On Allazan strest, the conditiens are not so bad, as this sewer, as far aa constructed, is very near the orover -5< grade and elevations, so that it crn be extended up as fir as the Plainwell ioad, if- so desired. The Hammond street sever, being laid to a very low grade, is at a low enough elevation so that it can be extended if desired. | Upon ivesticgnting the sewer, we found many of the lines in very bad condition, many of the oipes being conols‘te ly filled with filthy material, «nich cometimes extemded up in the man-holes, and upon opeming uo the man-holes, gave eff the foulest kind of gases, showing that the flow nad been stopped by the lack of flushines water, and by the flatness of the grades, causing sedimation to take place to such an ex- test that the vipes had been completely filled, and they hnd been in this condition so long that putrefaction had taken ‘place. The Hanmond sewer was in this condition, being conm- pletely filled, and with no aovvarent flow aleng its length and as fr up Nerth street to franklin. This was a surprise to us as the villsve authorities supposed they had tiis sewer flushed out only a few days before, byt the flushing evidently only consisted of turning a fire hose in the osive at Fair street until the flow was sterted, washing the sludge and sediment dow the sipe for a little way, making its con- ditios worse instead of flushing it out elean. The Frenklin street sewer was completely dry at its upper end, the two inch bore stream from the county drain on vorrell street having been shut off, and at the man-hele on Kalamazoo and Franklin. we found the worse conditions of all, hera the sludze and filth was One and thres-tenths of a foot deep; the next man- hole, down on the section line, was filled up to a dept of ~b- seven-tenths of a foot, and with no apparent flow, but at its junction with the trunk line 290 feet further down, we found the pipe flowing half full of clear water, show- ing that there was quite a perceptable leak in the line here. This may have been caused by the springs washing the dirt out from under the tile and allowing it to settle, and them break opm the joints, or else due to faulty construc- tion, and the joints never being cemented together properly in the first place. The rest ofthe pipes were either dry, due to the lack of customers having tapped to the sewer, or else was in good condition with enough flow to be self elean- ing. The trunk line north of Allegan street, which is a fifteen inch pipe, was found to be flowing eight-tenths of a foot deep, or 64% of the total depth, and as this system is comparatively new, and only a very small percent of the families alongs its course have taken advantage of it as yet, and also as it is the intentions to extend the lines and laterals further, it should have a factor of safety of at least three, or in other words, the present flow should be one-third the capacity of the pipe, instead of flowing near- ly two-thirds full. However, this may be partly due to the ground water, and pay be removed, to a small extent at least, by digging up the sewer where the worst leaks have ocourred, and relaying it upon some kind of strong mattress, and cengmt- ing the jointe thoroughly. There is a separate storm water sewer system to take care of the storm water in the business district, so that the -7e- sewage from this district ie not large, the principal con- tributors being the hetel, the barber shop and the lanndry. In the eastern portion of the tom, especially along the river, the private sewers are in operation, but it is only a matter of a few years before they will connect to the main sewer system, either ty their own free will, or else by Compulsory means. Proposed Systen. One of the main thinzs we endeavored to correct was the inadequacy of extending the system any further east, as originally designed. This would be inadequate for several reasons; first, vecause of the small size of the trunk line, which is flowing 64% full at the present time; second, because of the flat grades which would result in the extension of the lines to the Plainwell Road, and lastly, because of the fact that the population is increasing yearly and two systems would be necessary in a few years at the very best. We propose to have a trunk line upon Platt street, e- pyting into the river, by means of a trunk line running froa the corner of Platt and Court to the river, a distance of 300 feet, with a septic tank to remove the sgspemded matter, which is thereby subjected to hydrolytic or bacterial action. Ry these manans a portion of the orzanic matter is converted into unoffensive gasee or soluble compounds which pass off with the outflowing sewage. From this trunk line, a main 8. line is to be rum southeast up Plainwell Road to Morrell street, up Morrell street to Walnut street, up Wainut street to Hammond street and following Hammond west to the county drain; here for a flushing device, we propose to have a con- stant supply of water on hand by means of a small dam with slash boards; and by fitting a woeden head in the end of the tile here at the drain, with a two inch bore hole, an amount of water sufficient to keep the sewer clean will flow througn the line all the time. | We propose to run laterals east om Mitchell street, with a branch for a block north on Bdsell street, also a lateral west on Allegan running up within 100 feet of the man-hole on Fair, and with a branch taking in the block south on Wilmet, and a lateral west on Court street with short tranches running south for the distances of a block on Fair and Wilmot, also one north on Wilmot for a distance of 400 feet. Inasmuch as the Hammond street sewer is haid to such a flat grade that it requires constant attmtion, with flushing at short intervals of time, which is a big bother as well as expense, and also because upon snvestigattion we found it possible to extend the line and connect with the county drain. This is what we proposed to do. It is a distance of 1700 feet, and we found that it could have a grade of .26%, which will be sufficient, with a two inch bore stream flowing through the line, from the drain, the same as in the Franklin street sewer. And this improvement is practical from an- other standpoint other than that of flushing, as the popu- lation is thick qmough along this section of the street to warrant the extension alone. This proposed system takes in all the resident dis- trict in the eastern portion of the village not already sup- plied with a sewer system. The portion of the west of the trunk line should be connected to the trunk line, as this will not amount to enough sewage to make any particular dif- ference. The most economical way to take care of the por- tion acfoss the rivey is with a separate system, but as this will not be needed for a few years at the very best, we will leave its design for some future date. Automoatic flushing tanks should be installed at the dead ends of the laterals which do not have sufficient grade to be self-cleaning, These tanks should be built of con- orete and a constant flow of water allowed to flow into them from the mains. The automatic siphon discharges the contents into the sewer whenever the tamk becomes full, and sends a wave through the system, cleaning it out. If this method of flushing is not used, the following method should be followed whenever the lines anvvear to become Blocked, or to fill up. A temporary dam should be placed in a man-hole, and a section of the sewer and man-holes above the dam filled with water from the fire hydrant discharged through a hose, and then quickly removing the dam and allowing the water to flow rapid- -10- ly, and flush the sewer below, in this way force is given to the flushing water and better results are obtained. If place ; the trouble seems to be in one particular, or if the sewer iy? is in extra bad shape, a pill or round weoda@m ball, a little ealler than the pipe is placed in ene man-hole and allowed te go to the next man-hole; a fire hose is used again, and the water acoummulates behind the pill until sufficient pressure is developed to drive it forward. As the pill tends to float most of the water dischargesunderneath, and scours out deposits og the bottom of the sewer, thereby Cleaning it. We gave the proposed system definite grades, depending upon conditions, and in figuring the sizes of the pipes to be used, we took each city block in the residental district and divided it into thirty foot lots, allowing five persons to the lot, and estimating the amount of sewage to be one hundred and twenty-five gallons per @apita per day. The knowing the discharge in gallons per day, and the percent of grade, we determined the é¢ize of pipes to be used by a set of curves based upon Kutters formula, with the constant (n-0.013). But under no conditions would we allow a smaller pipe than eicht inehes, and we also aklowed for the fact that owing to the flatness of some of the sewers, the present Ones might be replaced by some of steeper grades, and con- necting tb the proposed systen. In the proposed system, we prepose to place man-holes at each corner, and also at the eds of lines which occur mid- way in a block. The septic tank should be designed for the maxinun flew of 100,000 gallons per day, which will take care of the flow for a few years, and additions should be made as needed. The tank shauld be covered in order to exclude the light and air, so that seotice action which is preform- ed with aneorbic bacteria will take place. It must be large enough to retain the flow of sewage for from eight to twenty-four hours or longer. The plat should be built in one compartment, in which both the sedimantation and septic action takes place. The estimated cost is vl, 000.00 The following table gives the results of our compu- tations and the sizes of pines we proposed to use in the different lines. PRUPUSS) SGl4as OF PIP. ¥rom To Proposed Sises. Mouth of main trunk Cor. of Court st. 15° sewer x Platt St. Cor. of Court St. Cor. of Platt? it. 12" & Platt St. & Plainwell R'd,. Cor. of Platt st. Cor. of ilitcnell 10* & Plainwell Rd. & Plainwell R'd. Cor, of Mitehell Cor. of Norrell Ge & Plainwell 'd. 4% Plainwell R'd. Cor. of Korrell Tne County Drain g* « Plainwell R‘'d. Cor. Platt st. Cor. of #ilmot ot. 10° & Plainwell Kd. «& Allecan 6t. Cor. Piatt St. Cor. wWhimot Gt. 10° « Court Ste cL Court ot e -l2- All other branches and laterals, including the addi- tion on the Hammond street sewer, to be 8" pipes. RECOMAXNDATIONS AND CONCLUSIONS. We recommend that the ends of all lines, not flushed vy the county drain, be flushed at regular intervals, not to exceed one week, Wy one of the methods explained in pre vious paragraphs, with the use of the fire hose. And as flushing is seldom effective for more than 800 to 1000 feet below the point of mtrance of the flushing water, man-holes further down than this should be inspected every few weeks, to insure their clean condition, and flushed out whenever necessary. Another improvement, which might be added, is to per- forate the mah-hole oovers. These, as they exist now, make perfect, tight covers over the man-holes, allowing no vmti- lation through thea. By having the covers perforated, con- siderable circulation will take place, as the cold air will go down through a certain number of them and up through the others. However, the ventilation of sewers is primarily a questions of aesthetics, and not of sanitation. Because of the fact that sedimen6 has settled in the inverts of the pipes, making a hard coating which is quite deep in places, and which cannot be removed by flushing alone, we recommend a thorough cleaning of all laterals by some mechanical means. The dest method to use consists of a heavy plank disk to which three short light chains are -13- fastened to as many bolts through the disk. Qe of these chains is attached to each side and one at the bottom of the disk, and their relative lengths are so arranged that when all are taut tie top of the disk will incline a little away from the rope. Upon theother side of the disk, at its top, is fastened another rope. By the latter, it is pulled a short distance into the sewer, lying flat; the other rope fis then pulled, when the disk rises into am up- right position and scrapes along the deposit in front of it. It is well not to draw this too far into the sewer at once, but to clean anly a few feet at each trip. The dirt can then be scraped to a man-hole and there removed by buckets. Ib case the sewer is mtirely stopped, so that no cord can be gotten through it, an opening must be forced through.