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WASTEWATER COLLECTION AND TREATMENT SYSTEM The Altoona City Authority’s wastewater collection and treatment system serves more than 20,100 customers. The system consists of approximately 230 miles of 6 in. thru 48 in. diameter sewer line, (Privately owned laterals add approximately 190 miles to the system), 3,200 manholes, three pump stations, two combined sewer overflow facilities (CSO's), and two single stage nitrification activated sludge treatment facilities. The collection system is divided into two drainage basins known as the Westerly and the Easterly gravity sewerage basins. These state-of-the-art CSO and treatment facilities are among the first systems in the eastern United States to integrate the treatment of wet weather flows, combined sewer overflow discharges and normal wastewater flows. Upstream of each treatment facility is a combined sewer overflow facility (CSO) for use during storm events to capture the "first flush" from the combined sewer system. The Westerly Facility located at Tuckahoe Park stores up to 1.3 MG of wastewater while the Easterly Facility located at Bellwood Avenue and Kettle Street stores up to 1.7 MG. Each CSO operates in the same way. When the flow in the interceptor sewer reaches a predetermined set point, the excess flow is diverted into the CSO. Before the wastewater enters the storage tanks, it passes through mechanically cleaned bar screen where any larger debris is removed. The debris is dropped onto a conveyor belt and transported into a holding pit before being disposed of in a permitted landfill. As the interceptor flow recedes the stored wastewater is pumped into the system for proper treatment. |
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COMBINED SEWER OVERFLOW DISCHARGE POINTS The Altoona City Authority’s Wastewater Division has two (2) points were combined storm water system and sanitary collection system waters are discharged to receiving streams. The receiving streams and discharge points are:
These areas have been posted with warning signs of potential harm during rainfall and high flow events. The signs state the following: NOTICE:
The wet weather discharges occur when the city receives 0.50 to 0.75 inches of rain or an accumulation of 5 inches or more of continual melting snow runs into the storm inlets. The average number of discharge occurrences is 38 per year at both discharge points. Any and all overflow occurrence is reported to DEP and EPA in the monthly discharge monitoring reports. Samples are taken once per month during an overflow event at both overflows for fecal coliform, pH, biochemical oxygen demand, total suspended solids, and ammonium nitrogen. Samples are take above the discharge points, at the discharge point, and below the discharge point to determine any stream impact. |
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INDUSTRIAL PRETREATMENT PROGRAM The industrial pretreatment program received its approval from the Environmental Protection Agency (EPA) Region Ill on June 18, 1984. At that time a total of eight (8) industries were permitted. Since that time, the program has grown and includes permitting of septic haulers, restaurants and super markets. As the year 2002 began, permits have been issued to:
The delivery of liquid biosolids and sludges have also been approved through the pretreatment program as long as they meet the Pennsylvania Department of Environmental Protections Chapter 271, Table 3 - Pollutant Concentrations and do not contain filamentous bacteria. |
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DESCRIPTION OF TREATMENT PROCESSES The wastewater from the city and a portion of Logan Township is conveyed to the treatment facilities also known as the Westerly and the Easterly, via three outfall sewers. The Westerly Facility also receives wastewater from a portion of Allegheny Township by a separate outfall. The design flow of the Westerly Facility is 9 MGD with a permitted monthly average of 13 MGD. The design flow of the Easterly Facility is 8 MGD with a permitted monthly average of 10 MGD. Each facility is capable of handling flows of up to 20 MGD during wet weather. These treatment facilities provide advanced secondary treatment capability normally removing 95% of organic and suspended solids. Both treatment facilities are controlled and monitored by identical computerized process control systems. Each facility is made up of five unit processes; preliminary treatment, flow equalization, activated sludge process, clarification & disinfection and, biosolids handling process. Plant operators, through the computerized control system screen, can monitor the entire treatment process, and they can also manually control equipment from this centralized system. Flows, tank levels, valve positions, pH and dissolved oxygen levels, and the operation of blowers, pumps, flow gates and equalization tanks are all controlled automatically from data fed to the computer. As the wastewater enters the preliminary treatment unit, the flow is diverted into channels which are equipped with mechanically cleaned bar screens. These screens provide the removal of larger debris and trash entering the facility. Immediately downstream from the bar screens the wastewater enters the aerated grit removal unit (s) where smaller debris (sand, gravel, cinders, etc.) are removed. Removal of grit and other debris is extremely important for the protection of pumps and equipment. The grit and debris are transported to a permitted landfill for proper disposal. To minimize the impact of peak wet weather flows, automatic controlled equalization tanks are provided. Flows in excess of 20 MGD are diverted into the equalization tanks and stored until the flow entering the facility recedes. The stored wastewater is then pumped into the system for proper treatment. The next stage of treatment is the Activated Sludge Process. This process is utilized to convert non-settleable substances in finely divided, colloidal and, dissolved form, into settleable sludge and to remove the sludge, thereby providing a high degree of treatment. The activated sludge process depends on groups of microorganism, primarily bacteria and protozoa, living on wastewater solids. as a purifying medium. These organisms are maintained in an aerobic environment by introducing air into a mixture of activated sludge and wastewater, after which the activated sludge is separated from the treated wastewater by settling. It is generally accepted that in the activated sludge process "adsorption" plays an important role in the removal of organic materials from the wastewater. In the aeration tanks the incoming wastewater and the activated sludge are mixed together by introduction of air. The aeration provides ample supply of oxygen for the growth and development of aerobic bacteria in the wastewater and activated sludge and promotes oxidation of the organic matter in the wastewater. The fine colloidal and suspended solids form a "floc". The principal action in the formation of the "floc" is generally assumed to be adsorption. . The colloidal solids are adsorbed by the floc already formed and are thus removed from the wastewater. The oxidation of organic matter in the wastewater and the formation of floc are much more rapid if the activated sludge that has been previously produced in the process of treatment is added to the incoming wastewater at the influent end of the aeration tanks(s). A plausible reason for this speeding up of the clarification process is that the activated sludge contains large numbers of aerobic bacteria that renders the sludge an active agent in oxidizing the wastewater. The continuous motion of the wastewater in the aeration tank is essential in order to bring all of the solids of the new wastewater in contact with the previously produced activated sludge and to prevent any settling of the sludge particles. The aeration effluent then flows into the circular clarification tank(s) where the separation of sludge and the purified liquor is accomplished. When more than one clarifier is in use it is important to maintain the flow to the tanks at a uniform rate. The velocity of the incoming wastewater is reduced to a fraction of an inch per sec. to allow the solid material ("floc") to settle to the bottom as the liquid continues over a weir into the effluent channel. A baffle is placed in front of the effluent weir to prevent floating material (scum) from reaching the weir. A rotating scraper arm projects above the water surface to push the scum toward a trough where it is skimmed off and pumped to the primary sludge digestion tank. Proper baffling for good distribution and good skimming practices are most important as any solids or scum carried over the final weir go directly into the receiving stream. The solid material or sludge floc is deposited onto the floor of the tank. This sludge is drawn off be means of a rotating scraper and slip tubes by hydrostatic pressure. It is important that the sludge be kept flowing from these tubes at all times. It is also essential. that the sludge be drawn from each clarifier at a uniform rate. The sludge removal from the clarifier is continuously pumped to the head of the aeration tank(s) and mixed with the incoming wastewater. The concentration of activated sludge (mixed liquor) is maintained at a predetermined level by the facility operator. The clarified liquid flows into the effluent channel and into the ultraviolet disinfection reactor{s). As the flow passes through the reactor(s) the ultraviolet light disrupts DNA in bacteria, viruses, molds, algae and other microorganisms causing cell death or inactivity. The disinfected water is then discharged into the receiving stream. The Westerly Facility empties into the F rankstown Branch of the Juniata River and the Easterly Facility empties into the Little Juniata. For more information on Ultraviolet Disinfection of Wastewater click here As the concentration of solids increases in the aeration system, a portion of the retum activated sludge from the clarifier is wasted from the system and pumped to a gravity belt thickener. A polymer is added to enhance the separation of water and solid. A sludge of between 3 and 4 percent is pumped from the thickener to a primary digestion tank. As the amount of food decreases the microorganisms become competitive and eventually begin to rely on each other for food. The sludge is transferred to a secondary digestion tank as necessary to provide enough time for the aerobic stabilization of organic matter to a relatively stable or inert organic and inorganic compound or biosolid. (Usually 20 to 40 days hydraulic retention time). The digested or stabilized biosolids are drawn from the bottom of the secondary digester and pumped to a belt filter press. A polymer is again added to enhance the separation of liquid and solid, resulting in a sludge cake of 18 to 20 percent solid. The biosolids are stored on site for land application on approved and permitted farms or hauled to a permitted landfill for disposal. |
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ULTRAVIOLET DISINFECTION OF WASTEWATER The Old Way In 1991, ACA spent about $8,000 for chlorine. Stored on site in 2,000-pound canisters, 80 to 150 pounds of chlorine were added to the chlorine contact tank daily. After disinfection, plant effluent contained low levels of chlorine which threatened local aquatic life. Also, while connecting, emptying, and changing canisters, plant operators risked exposure to chlorine gas. Several times toxic leaks forced workers to use protective breathing equipment. The New Way UV disinfection helps ACA treat wastewater economically while minimizing environmental health and safety impacts. All AquarayTM closed chamber horizontal system, supplied by Ultraviolet Purification Systems, Inc. of Bedford Hills, NY, was installed at ACA in December 1991. The system operates continuously treating up to 20 million gallons per day. Composed of 2 horizontal Type 304 stainless steel cylindrical reactors, it operates under pressure up to 30 pounds per square inch. Both reactors contain 348 UV quartz enclosed lamps divided equally into 2 banks. Controlled by electromagnetic ballasts, lamps activate sequentially as wastewater flow increases. The banks in the first reactor handle flows up to 10 MGD while heavier volumes activate the banks contained in the second reactor. As wastewater passes through the unit, UV light disrupts DNA in bacteria, viruses, molds, algae, and other microorganisms causing cell death or inactivity. Treated wastewater is then discharged. Performance data are displayed on a remote UV intensity meter and chart recorder. If a lamp burns out or light intensity drops, alarms alert personnel. The UV unit can be operated by remote control or manually and requires no special training. The Results ACA has found an environmentally responsible, convenient, and cost-effective way to disinfect municipal wastewater discharge. Performance is equal to chlorine. Effluent easily meets NPDES permit requirements. As a result, adequate disinfection is provided, permit requirements are met, and local aquatic life is protected. By lessening reliance on chlorine, ACA also reduced the potential for worker exposure to chlorine gas. The Advantages Safety: Simplified Compliance: Reduced Effluent Toxicity: Maintenance and Cleaning: Reliability: |
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The Easterly Wastewater Treatment produces on average 3,325 wet tons or 605 dry tons of biosolids per year, while the Westerly Wastewater Treatment Facility produces on average 3,422 wet tons or 622 dry tons of biosolids per year. The biosolids program received its first farm approval under the Pennsylvania Department of Environmental Protections Chapter 275 regulations on January 20, 1995. The Altoona City Authority applied for and received permits under the General Permits Regulation (Chapter 271) for the Easterly (PAG-08-3511) and Westerly (PAG-08-3512) Wastewater Treatment Facilities on April 1, 1998. Currently this program has six farms approved. They are; The Robert Smith Farm & Robert Himes Farm located in Antis Township; and the David Sollenberger Farm and Fred England Farm located in Woodbury Township, Blair County; The William Replogle Farm located in Taylor Township, Blair County; and the Bill & Deb Hoover Farm located in Warriors Mark Township, Huntingdon County. Total spreadable acres at these farms are:
Description of Biosolids Biosolids are a nutrient rich organic product of the wastewater treatment facilities which can be used as a fertilizer. During the wastewater treatment process, solids are removed from the wastewater and treatment in our four (4) one million gallon capacity aerobic digesters (2 at each facility) where the organic solids are stabilized, reducing the volume by about 50%. After digestion, polymer is added to reduce the amount of water leaving a cake of 16% to 20% solids. Why Use as a Fertilizer? Biosolids are an excellent source of essential plant nutrients and organic matter. The addition of this organic matter may reduce erosion by improving soil texture and increases the soil's ability to hold moisture. Nutrients are returned to the soil where they can enhance plant growth. It also reduces the amount of solid waste that is filling our landfills. Is It Safe? The US Environmental Protection Agency (EPA) issued the biosolids rule in 1993. It is the most comprehensive set of regulations ever. EPA and a panel of experts examined all aspects of biosolids in the environment, including potential effects on groundwater, air and soil quality, surface run off and food crops. The PA Department of Environmental Protection adopted these same regulations with additional and more stringent parameters, reporting requirements and records keeping requirements in 1997. These biosolids rules set quality limits for trace metals and requires pathogen and odor reduction. Biosolids are carefully applied in amounts that provide only the amount of nitrogen needed by the particular crop. The Altoona City Authority biosolids are spread on corn, alfalfa, hay, and small grains for dairy cattle consumption. Class A and Class B Biosolids The Altoona City Authority aerobically digests biosolids at its Easterly and Westerly Wastewater Treatment Facilities to meet the Class B requirements. In practical terms, the difference between a Class A and B biosolid is in the type of treatment utilized to reduce pathogens. To meet the Class A requirements, the biosolids must have additional treatment to eliminate remaining pathogens (i.e. composting, lime stabilization, etc).
The Class A and B designation also establishes how the biosolids may be distributed. Class A is required for biosolids to be sold or given away as a garden or lawn fertilizer. Additional permitting, public notification, and site management are required for Class B biosolids to be used a fertilizer on farmers fields. |
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PROHIBITED DISCHARGES TO THE ALTOONA CITY AUTHORITY'S WASTEWATER COLLECTION SYSTEM
Questions regarding prohibited discharges to the wastewater collection system and the combined sewer system may be addressed to the Altoona City Authority's Pretreatment Office at 949-2246 or 949-2250. Questions regarding odors from storm water catch basins may be addressed to the City of Altoona Highway Department at 949-2211 or 949-2212. Requirements for Relay of Sewer Laterals Any existing customer may make application for replacement of the existing sewer lateral at the Department of Public Works, Altoona City Hall. The cost of the new relay is five hundred seventy-five dollars ($575.00) When a customer requests the installation of a replacement sewer lateral, that customer shall have his plumber install a new clean out at the property line. The Altoona City Authority Wastewater Division Sewer Maintenance Crew shall install the new lateral only after the plumber has finished the installation of said clean out. |
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BIO-AUGMENTATION AND SURCHARGE PROGRAM The wastewater collection system has encountered obstructions and blockages caused by grease, fats, and oil build up as a result of the discharge from the numerous restaurants. These restaurants discharge into the Pleasant Valley, South Altoona, and Westerly Interceptor Sewers to the Westerly Treatment Facility and the Fairview, Wehnwood, Juniata Interceptor Sewer to the Easterly Treatment Facility where the grease collects as grease balls within the aerated grit chambers of the Pretreatment Buildings. Beginning in July 1995, the Altoona City Authority started issuing permits to the restaurants connected to the collection system. Stipulated in the individual permits is the sampling for surcharge purposes requirement. The quarterly sampling (for BOD, TSS, and n-hexane extractable oil and grease) is accomplished by either Pretreatment Program personnel or local independent laboratories contracted by the permitted restaurant. In connection with the surcharge program, in November 1995, the Wastewater Division embarked on inoculating the six (6) areas of most reported obstructions and blockages with a bacteria formulated for collection systems to remove grease build up. The inoculation period ended in January 1996 and a monthly maintenance schedule stated in February 1996. The surcharges collected from the restaurants covers the cost of purchasing the ten (10) twenty-five (25#) containers of bacteria bags per year. Since the initial inoculation and permitting of the food service customers, the obstructions and removal of obstructions has been cut by 75 to 80%. The one area of most concern has obstructions due to the poor design and location of the sewer which contributes to the grease build up within the manholes. Any questions relating to these programs may be addressed to the Pretreatment Coordinator |
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