Sewer system The proposed sewer system has been designed to care for sanitary sewage only. The sewers comprising the system vary in size from 8 to 15 inches in diameter except the outlet sewer leading from Riverside avenue to the disposal plant which is to be 20 inches in diameter. The sewers are for the most part to be constructed on fairly steep slopes and manholes are to be installed at all points of change of slope and alignment. Flush tanks are to be placed at the upper ends of nearly all lateral sewers. Inverted siphon The sewage from the northerly portion of the village is to be carried under a small brook which flows through the village near Brook street by means of an inverted siphon in Riverside avenue. The line leading to the siphon is to be 15 inches in diameter. The siphon which is to be of 16-inch cast-iron pipe is to be about 20 feet long. The inlet and outlet ends of the siphon are to consist of "Y" branches which will facilitate cleaning the siphon. Although it is usual to have inverted siphons constructed with duplicate pipes so arranged that either or both pipes may be used at one time, it may not be necessary at this time to provide for two pipes owing to the comparatively short length of the siphon and the relatively large size of pipe in this case. An additional pipe can be added whenever required. The bottom of the outlet manhole of the siphon should, however, be provided with channels so as to facilitate the flow through the outlet manhole into the main outiall sewers. Sewage disposal It is proposed to treat the sewage of the village in a sewage disposal plant consisting of a screening plant and a chlorination plant with provisions for pumping the effluent at certain high water stages of the river. The disposal plant is to be located near the bank of the Hudson river on the southerly side of the dock near the foot of Brook street extended. It appears from data furnished by the designing engineers that it was found to be impracticable to convey the sewage to a site more remote from the developed sections of the village without pumping. Screening plant The sewage upon reaching the disposal plant is first to be passed through an inclined bar screen composed of 2-inch by 3-inch bars spaced 2 inches in the clear. After passing through this screen it is to flow through a covered concrete channel to a Riensch-Wurl screen 8 feet in diameter having perforations 3/4 inches wide and 2 inches long. The screened effluent from this fine screen is to flow into an outlet chamber or pump well near the entrance of which provisions are made for treating it with liquid chlorine. The pump well has a capacity below the average high water mark of about 3,000 gallons. Under ordinary conditions the treated sewage is to be discharged into the Hudson river by gravity through a 12-inch cast-iron outfall sewer extending to a point within about 50 feet of the end of the dock. Provisions are made for by-passing the Riensch-Wurl screen in case of emergency. The sewage will, however, be passed through the bar screens at all times before being discharged into the river. As noted above the channel of flow between the bar screen and the Riensch-Wurl screen is shown covered by the plans. This channel should be left open or should be covered by a removable grating in order to make it readily accessible for cleaning and inspection. On the cross section through the screen house the elevations of the average low water, the average high water and the maximum high water stages of the river at the disposal plant are marked -3.0.0.0 and -2.0 respectively and the elevations of the invert of the sewer and of the inlet channel at the Riensch-Wurl screen is marked 0.5 which would indicate that the average high water mark of the river is 2 foot above the invert of the sewer at the plant. Graphically, however, the average high water mark is shown about 2 feet lower instead of 2 foot higher than the elevation of the invert of the sewer at the plant with a corresponding difference between this elevation and the elevations of the low and the maximum high water marks. This discrepancy is somewhat misleading and would indicate that there had been a mistake in drawing up the plans or that two different datum planes had been used in designing the plan. This matter was called to the attention of one of the designing engineers when he presented the plan. He stated that the graphical representation of the various stages of the river is not shown correctly on the plans but that the elevations marked on the plans in figures were correct. It would appear therefore, that it will be possible for a considerable period in the future to operate the plant by gravity flow at all stages of the river below average high tide. When the water in the river is above the average high water mark it is planned to close the inlet end of the effluent pipe at the pump well by means of a hand operated 18-inch sluice gate and to pump the effluent from the pump well into the river through the effluent pipe with 2 6-inch centrifugal pumps located in a dry well adjacent to the pump well. These pumps which are to have a capacity of 900 gallons per minute each under a head of 10 feet are to be driven by 2 automatically operated 10 horsepower electric motors. An electric signal device is to be installed to notify the operator in case of a failure of the pumping equipment. Chlorination plant The plans provide for treating the screened effluent with liquid chlorine. According to the report of the designing engineer the chlorine apparatus is to be of the Wallace & Tiernan type or equal and is to be capable of applying from 10 to 70 pounds of chlorine per day. It is presumably intended to sterilize the effluent on account of the bathing beach which it is understood is located on Croton Point from 4 to 1 mile from the disposal plant. In view of the fact that this bathing beach is well removed from the point of discharge of the effluent and since sterilization of sewage effluents in this district has not been required, it would hardly seem necessary that sterilization should be provided at this time except possibly during the summer months if the village should so desire. If the sterilizing apparatus is to be used, I am of the opinion that not less than 10 parts of chlorine gas per million parts of sewage treated should be applied. This would be equal to about 83 pounds of chlorine per million gallons of sewage treated. Conclusions and recommendations From our careful examination of plans it is found that the proposed sewer system and sewage disposal plant if properly constructed and if maintained with care and efficiency should satisfactorily meet the local requirements. The proposed disposal plant should produce an effluent that may be safely discharged into the river at this time without objection. It will be necessary, however, to at all times have the plant operated under intelligent supervision in order to obtain satisfactory results and the village authorities should, therefore, provide for the proper supervision and operation of the plant. If the plant is neglected it will soon be out of repair and the function for which it was designed will be largely if not wholly defeated. In view of the above I would recommend that the plans be approved and that a permit be issued allowing the discharge of effluent from the proposed sewage disposal plant into the Hudson river near the foot of Brook street. I would further recommend that the permit contain in addition to the usual revocation, modification and restriction clauses the following conditions: 1. That the channel between the bar screen and the Riensch-Wurl screen be left open or covered with removable gratings. 2. That whenever required plans for additional or more complete treatment of the sewage of the village shall be submitted for approval. Respectfully submitted, ALBANY, N. Y., February 28, 1917 THEODORE HORTON, PERMIT Application having been duly made to the State Commissioner of Health, as provided by section 77 of chapter 49 of the Laws of 1909, the "Public Health Law as amended by chapter 553 of the Laws of 1911, constituting chapter 45 of the Consolidated Laws, permission is hereby given to the Board of Trustees of the village of Croton-on-Hudson to discharge effluent from the sewage disposal works to be constructed in connection with the proposed sewer system for the village into the waters of Hudson river near the foot of Brook street within the municipality of Croton-on-Hudson in accordance with the plans accompanying the petition, under the following conditions: 1. That this permit shall be revocable at any time or subject to modification or change when in the judgment of the State Commissioner of Health such revocation, modification or change shall become necessary. 2. That the issuance of this permit shall not be deemed to affect in any way action by this Department on any future application that may be made for permission to discharge additional sewage or effluent into the waters of this State. 3. That both the sewer system and the sewage disposal works shown by plans approved this day shall be fully constructed in complete conformity with such plans or approved amendments thereof. 4. That only sanitary or domestic sewage and no storm water or surface water from streets, roofs or other areas shall be admitted to the proposed sewers. 5. That no sewage sludge or screenings from any part of the disposal works shall be discharged into the Hudson river or any other watercourse. 6. That the channel to convey sewage from the bar screen to the Riensch-Wurl screen shall be open or be covered by removable grating. 7. That whenever required by the State Commissioner of Health satisfactory detailed plans for additional works for more complete treatment of the sewage of the village of Croton-on-Hudson shall be submitted for approval; and after approval of the said plans any or all portions of such additional or supplementary works for more complete treatment of the sewage shall be constructed and put in operation at such time or times thereafter as said Commissioner may designate. LINSLY R. WILLIAMS, Acting State Commissioner of Health March 2, 1917 DELHI (Delhi Products Co.) HERMANN M. BIGGS, M.D., State Commissioner of Health: I beg to submit the following report on our examination of plans for the disposal of wastes from the Delhi Co-operative Creamery at Delhi, Delaware county, submitted to this Department for approval on June 7, 1917. According to the data submitted by the designing engineer the plant of this company is to be used as a skimming station where it is proposed ultimately to handle about 6,000 gallons of milk per day. Although the plant is. equipped to make butter it is not expected that any will be made at this plant and no cheese will be manufactured so that there will be no whey or buttermilk to care for. The wastes at the plant are to consist of floor washings and wash water from milk cans and utensils and are estimated at 600 gallons per day. It is proposed to treat these wastes in a disposal plant consisting of 6 settling tanks having a capacity equal to about 800 gallons each or somewhat in excess of one day's flow of wastes. Each tank is to be 8 feet long, 4 feet wide by 4 feet 6 inches inside dimensions with a depth below the flow line of 3 feet 6 inches. A baffle is to be placed in front of the inlet and outlet of the tank. The baffles are shown extending only a few inches above the flow line of the tank. Although the settling tank appears to have more than ample capacity to care for one day's flow of sewage, I am of the opinion that better results would be obtained if the tank be increased in depth to not less than 5 feet below the flow line. This change could be made without increasing the capacity of the tank by decreasing the length and the width of the tank sufficiently to obtain the required capacity. The baffle board should also be raised to an elevation not less than 9 inches above the flow line of the tank. The tanks are to be operated in rotation on successive days. The tank filled one day is to be allowed to stand full for 4 or more days before it is emptied. After a certain amount of sludge has accumulated the supernatant liquid will be drawn off and the sludge allowed to stand for a month or more until it is thoroughly decomposed. If this long period of detention of the sludge should not prove satisfactory or give rise to objectionable conditions the sludge could of course be drawn off at more frequent intervals. No statement is made nor do any provisions appear to have been made for the disposal of sludge. The sludge should not be discharged into any stream or other body of water but should he buried at a sufficient distance from any building to prevent the creation of objectionable conditions. The effluent from the settling tanks is to be discharged into the Delaware river through effluent pipe consisting of 780 feet of 6-inch tile pipe. According to the report of the designing engineer a fall of 22 feet is available, equal to an average slope of 2.8 per cent. From our careful examination of the plans it would appear that the proposed disposal plant should satisfactorily care for the wastes from the creamery if modified in certain respects as indicated above. I would, therefore, recommend that the plans be approved on the following conditions: 1. That the depth of the settling tanks be increased to not less than 5 feet below the flow line without increasing the capacity of the tank. 2. That the baffles near the inlet and outlet of the tanks he raised to an elevation of not less than 9 inches above the flow line of the tanks. 3. That whenever required plans for supplementary or more complete treatment of the wastes shall be submitted for approval. Respectfully submitted. ALBANY, N. Y., June 22, 1917 THEODORE HORTON, PERMIT Application having been duly made to the State Commissioner of Health, as provided by section 76 of chapter 49 of the Laws of 1909, the "Public Health Law " as amended by chapter 553 of the Laws of 1911, constituting chapter 45 of the Consolidated Laws, permission is hereby given to the Delhi Products Company, Inc., to discharge effluent from the proposed works to treat the waste water and washings from the creamery of said.company at Delhi into the waters of Delaware river near said creamery within the municipality of Delhi in accordance with the plans accompanying the petition, under the following conditions: 1. That this permit shall be revocable at any time or subject to modification or change when in the judgment of the State Commissioner of Health such revocation, modification or change shall become necessary. 2. That the issuance of this permit shall not be deemed to affect in any way action by this Department on any future application that may be made for permission to discharge additional sewage or effluent into the waters of this State. 3. That no human excreta or washings and no whey, skimmed milk or other liquid wastes containing considerable amounts of putrescible organic matter shall be discharged into the settling tanks. 4. That no sludge or scum from the settling tanks shall be discharged into the Delaware river or any other watercourse or body of water. 5. That the depth of the settling tank shall be increased to not less than 5 feet below the flow line, the width and length of the tanks being decreased if desired to maintain the capacity as shown by the plans. 6. That a baffle near the inlets and outlets of the tank shall be raised to the elevation of not less than 9 inches above the flow line of the tanks. 7. That whenever required satisfactory detailed plans for supplementary or more complete treatment of the wastes shall be submitted to this Department for approval; and that after approval such works shall be constructed and put in operation whenever required by the State Commissioner of Health. October 8, 1917 M. NICOLL, JR., Deputy State Commissioner of Health DELHI (N. Y. State School of Agriculture) HERMANN M. BIGGS, M.D., State Commissioner of Health: I beg to submit the following report on our examination of revised plans for sewage disposal for the Home Economics Building of the New York State School of Agriculture and Domestic Science at Delhi, resubmitted to this Department for approval by the State Architect on May 31, 1917. These plans were first submitted for approval by the State Architect on April 18, but it was found from our preliminary examination of them that although they had in general been designed to meet the local requirements for sewage disposal, the subsurface irrigation system should be extended and modified and the plans were accordingly returned to the State Architect for modification on April 24, 1917. The plans now submitted provided for a sewage disposal plant consisting of a settling tank, dosing tank and subsurface irrigation system divided into two sections. According to the data submitted with the plans the maximum number of students to be cared for at the Home Economics Building will be 60 and the water consumption is estimated at about 30 gallons per capita. The report submitted with the plans states that the soil at the site of the subsurface irrigation field is of a loose gravelly nature for a depth of several feet and well adapted for the disposal of sewage by means of subsurface irrigation. The settling tank is to be 11 feet long, 5% feet wide and 51⁄2 feet deep inside dimensions with a depth below the flow line of 4%1⁄2 feet. The tank will, therefore, have a capacity of approximately 2,000 gallons and will provide for a detention of the sewage of about 1 day when serving 60 persons based on an assumed daily sewage contribution of 30 gallons. The tank is provided with a 4-inch sludge pipe controlled with a 4-inch gate valve. This pipe terminates at a plugged outlet about 25 feet from the tank. No statement is made as to the method of disposal of the sludge. The sludge should be disposed of on a properly constructed sludge bed or it should be deposited in trenches and burned at a sufficient distance from any building to prevent the creation of objectionable conditions and sufficiently far from any stream or body of water to prevent its contamination. |