|
Technical Description
<br /> clarifier after transfer of the supernatant, is returned to the aeration chamber. After settling, this
<br /> 66%represents 100% of the activated sludge.
<br /> (NOTE: The SSV-60 test, although somewhat similar, is not to be confused with the more com-
<br /> monly used SVI test, (sludge volume index). The SVI is used to determine the volume of sludge
<br /> compared to its weight, and thus its settleability, whereas the SSV-60 test determines only the
<br /> settled-sludge-to-supernatant ratio.)
<br /> Characteristics of the activated sludge play an important part in this settling time. A good food
<br /> source, along with adequate oxygen, produces a fluffy bacteria. It is these light, fluffy bacteria
<br /> that produce the floccing action in the clarifier. Because both the food source and oxygen are de-
<br /> pleted in the clarifier, the sludge loses its fluffiness and is pulled down by gravity, leaving a visi-
<br /> ble separation between the supernatant, or clarified, liquid and the sludge.
<br /> If the SSV-60 test indicates sludge wasting is required,the following procedure should be used:
<br /> After the supernatant has been transferred from the clarifier, 5%percent of the remaining sludge,
<br /> which has no odor,may be returned to the buffer tank, discharged for direct drying on open beds,
<br /> diverted to an optional sludge digester, or accumulated for disposal in designated areas.
<br /> EXAMPLE:-A 30,000-gpd Nitro-Raptor system will batch 6,494 gallons of mixed liquor to the
<br /> clarifier from the aeration chamber. After a 60-minute settling period in the clarifier, 2,164 gal-
<br /> lons of the batch in the clarifier are removed as supernatant and the remaining 4,329 gallons are
<br /> classified as sludge. A minimum of five percent of the sludge,or 217 gallons,'wouJd be wasted.
<br /> This wasting procedure follows recommendations described in Operation of Waste-Treatment
<br /> Plants published by California State University, Sacramento, Department of Civil Engineering,
<br /> in cooperation with the California Water Pollution Control Association for the Federal Environ-
<br /> mental Protection Agency, Office of Water Program Operations.
<br /> Nitro-Raptor systems have a field history of extremely low sludge generation. The Nitro-Raptor
<br /> process, when compared to a flowthrough system, will produce a much higher quality effluent
<br /> with far less sludge production.
<br /> The Nitro-Raptor process concept is covered, in part, in federal regulatory agency guidelines as
<br /> detailed in Recommended Design Criteria for Activated Sludge Processes.
<br /> The Nitro-Raptor batch-reactor process is a modified version of the activated-sludge process.
<br /> Known as a complete-mix system, it treats wastewater in batches, sequentially controlled by a
<br /> microprocessor system. This unique feature makes possible effective, quality treatment of sew-
<br /> age,regardless of input surge-flow patterns. The principal steps are:
<br /> Raw sewage/wastewater enters the aeration tank, where previously developed biological floc par-
<br /> ticles arc brought into contact urith the incoming, suspended organic matter. The organic matter
<br /> is a carbon and energy source for cell growth and is converted into cell tissue and/or converted to
<br /> carbon dioxide (CO2).
<br /> The digestion process in the aeration chamber is initiated by the introduction of air into the in-
<br /> coming wastewater. The soluble material, oxidized material, settleable and suspended solids
<br /> form the mixed liquor. This biological mass is referred to as the Mixed Liquor Suspended Solids,
<br /> (MLSS), or Mixed Liquor Volatile Suspended Solids(MLVSS), and consists mainly of microor-
<br /> ganisms, inert suspended matter, and nonbiodegradable suspended matter.
<br /> -5-
<br /> 7-H Technical Services Group,Inc.
<br />
|