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  1. Article: Carbon and nutrient removal from on-site wastewater using extended-aeration activated sludge and ion exchange.

    Safferman, Steven I / Burks, Bennette D / Parker, Robert A

    Water environment research : a research publication of the Water Environment Federation

    2004  Volume 76, Issue 5, Page(s) 404–412

    Abstract: The need to improve on-site wastewater treatment processes is being realized as populations move into more environmentally sensitive regions and regulators adopt the total maximum daily load approach to watershed management. Under many conditions, septic ...

    Abstract The need to improve on-site wastewater treatment processes is being realized as populations move into more environmentally sensitive regions and regulators adopt the total maximum daily load approach to watershed management. Under many conditions, septic systems do not provide adequate treatment; therefore, advanced systems are required. These systems must remove significant amounts of biochemical oxygen demand (BOD) and suspended solids, and substantially nitrify, denitrify, and remove phosphorus. Many existing advanced on-site wastewater systems effectively remove BOD, suspended solids, and ammonia, but few substantially denitrify and uptake phosphorus. The purpose of this research was to design and test modifications to an existing on-site wastewater treatment system to improve denitrification and phosphorus removal. The Nayadic (Consolidated Treatment Systems, Inc., Franklin, Ohio), an established, commercially available, extended-aeration, activated sludge process, was used to represent a typical existing system. Several modifications were considered based on a literature review, and the option with the best potential was tested. To improve denitrification, a supplemental treatment tank was installed before the Nayadic and a combination flow splitter, sump, and pump box with a recirculation system was installed after it. A recirculation pump returned a high proportion of the system effluent back to the supplemental treatment tank. Two supplemental treatment tank sizes, three flowrates, and three recirculation rates were tested. Actual wastewater was dosed as brief slugs to the system in accordance with a set schedule. Several ion-exchange resins housed in a contact column were tested on the effluent for their potential to remove phosphorus. Low effluent levels of five-day biochemical oxygen demand, suspended solids, and total nitrogen were achieved and substantial phosphorous removal was also achieved using a 3780-L supplemental treatment tank, a recirculation ratio of 5:1, and a fine-grain activated aluminum-oxide-exchange media. Good results were also obtained with an 1890-L supplemental treatment tank and a recirculation ratio of 3:1. The most significant benefit of the supplemental treatment tank, in combination with the recirculation system, appears to be the low nitrogen concentration dosed to the Nayadic. By reducing the nitrogen concentration and spreading out its mass over time during no-flow periods, the Nayadic's inherent low-level denitrifying capacity was more closely matched and effective treatment was achieved.
    MeSH term(s) Aluminum/chemistry ; Carbon/isolation & purification ; Ion Exchange ; Nitrogen/isolation & purification ; Phosphorus/isolation & purification ; Sewage/chemistry ; Sewage/microbiology ; Waste Disposal, Fluid/methods ; Water Movements ; Water Purification/methods
    Chemical Substances Sewage ; Phosphorus (27YLU75U4W) ; Carbon (7440-44-0) ; Aluminum (CPD4NFA903) ; Nitrogen (N762921K75)
    Language English
    Publishing date 2004-09-16
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1098976-6
    ISSN 1554-7531 ; 1061-4303 ; 1047-7624
    ISSN (online) 1554-7531
    ISSN 1061-4303 ; 1047-7624
    DOI 10.2175/106143004x151671
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Maximizing total nitrogen removal from onsite-generated wastewater.

    Safferman, Steven I / Novellino, Marianna I / Burks, Bennette D / Parker, Robert A

    Journal of environmental health

    2006  Volume 68, Issue 6, Page(s) 25–32

    Abstract: The research reported here examined the use of hydraulic loading strategies to maximize nitrogen removal from onsite-generated wastewater. These strategies are made practical by the inherently intermittent flow of onsite-generated wastewater. ... ...

    Abstract The research reported here examined the use of hydraulic loading strategies to maximize nitrogen removal from onsite-generated wastewater. These strategies are made practical by the inherently intermittent flow of onsite-generated wastewater. Experimentation was conducted at the Western Regional Wastewater Pretreatment Facility in Montgomery County, Ohio, with an established, full-scale onsite wastewater treatment system rated at 500 gallons per day. The onsite wastewater treatment unit was fed primarily with domestic wastewater that had passed through fine screens and grit removal. The dosing schedule was intermittent, representing what would be expected from onsite-generated wastewater. Oxidation occurred in the aeration tank and potentially on the solid-liquid filtration socks within the aeration tank. All major wastewater characterization parameters were monitored during the approximately one-year study, including five-day biochemical oxygen demand (BOD;), total suspended solids (TSS), nitrate, total nitrogen, pH, and alkalinity. Excellent removal of BOD5 and TSS resulted, with the effluent concentration of each parameter substantially and consistently below 10 mg/L for all operating conditions. Excellent total nitrogen removal occurred, typically to below 10 mg/L of nitrogen when the instantaneous flow of wastewater was low, even when the daily hydraulic loading was high. The removal of nitrogen was attributed to microbial biodegradation. This result indicates that the onsite wastewater treatment unit has an inherent denitrification capacity that can be matched with an equalized-hydraulic-loading strategy. The practical ability to equalize and reduce instantaneous loading results from the inherently intermittent nature of the flow associated with onsite wastewater treatment.
    MeSH term(s) Filtration ; Nitrogen/isolation & purification ; Oxidation-Reduction ; Waste Disposal, Fluid/methods ; Water Movements ; Water Supply
    Chemical Substances Nitrogen (N762921K75)
    Language English
    Publishing date 2006-01
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 411432-2
    ISSN 0022-0892
    ISSN 0022-0892
    Database MEDical Literature Analysis and Retrieval System OnLINE

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