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Aerobic System Process

4 Stage Process System

  • Single Tank Design
  • The only NSF standard 40 approved unit with time operations
  • 6/10 effluent quality
  • BOD5 – 6 mg/L
  • TSS – 10 mg/L
  • Pre–cast concrete tank meeting CSA standards
  • Local distributers available for sales and service
  • No submerged motors, diffusers or plumbing
  • 1725 RPM motor/high torque
  • Build in flow equalization
  • Bio–Kinetic system for tertiary treatment (3rd chamber)
  • Built in Chlorination–Dechlorination
  • Requires less pumping than septic tanks and competitive units without pretreatment
  • Pateneted Bio–Static sludge return
  • Simple controls with tamper evident seals
  • Reduced installation cost
  • Lowest energy consumption
  • Exceeds NFS Standard 40 and USEPA Secondary limits
  • Significant reduction in pollutant load
  • All components easily accessible from grade
  • Extended bearing and motor life with no reduction in performance
  • Controlled peak hydraulic flow conditions
  • Assured consistent effluent quality
  • Reduced operating costs to homeowner and longer unit life
  • No requirement for additional pumps
  • Easy to service, maintain, and troubleshoot
  • Accommodates broad range of applications for domestic wastewater
  • Best overall value in the market

Operating Conditions

Total holding capacity of the system offers a minimum of 48 hour retention of the daily flow. The Pretreatment Chamber provides at least 18 hour retention, the Extended Aeration Chamber provides at least 24 hour retention, and the Clarification Chamber provides at least 6 hour retention. The non-mechanical Flow Equalization device increases each individual chamber and total system retention time in direct proportion to loading. Design of the system includes a compartmented tank and non-mechanical Flow Equalization device to insure successful treatment performance without upset even when the significant runoff period is 6 hours. Hydraulic design considerations of the system and Flow Equalization device shall be such that irregular peak flow factors as high as four shall not interrupt hydraulic reliability within the system.

Pretreatment Chamber

The Pretreatment Chamber is an integral part of the wastewater treatment system. All domestic wastewater is Preconditioned and Flow Equalized while passing through the Pretreatment Chamber prior to being introduced to the extended aeration chamber. The outlet of the Pretreatment Chamber is equipped with a discharge tee that extends vertically into the liquid so that only the preconditioned equalized flow from the center area of the chamber is displaced to the extended aeration chamber. The discharge tee and transfer port are of adequate size to handle a peak flow factor of four without restricting the outlet and disturbing hydraulic displacement to the extended aeration chamber. A removable inspection cover is provided on the top of the Pretreatment Chamber to allow the tank and transfer tee readily available for inspections. As a safety measure, the uncovered opening is small enough to insure that the tank cannot be entered during inspections or service calls.

Aeration Chamber

The Extended Aeration Chamber provides in excess of 24 hour retention of the equalized daily flow. The chamber is a sufficient size to provide a minimum of eighty cubic feet of tank capacity per pound of applied BOD. The Aeration Chamber length-width-depth ratio shall be designed to insure uniform tank mixing and provide optimum treatment. The Aeration Chamber is an integral part of the system flow path and constructed of properly reinforced five thousand PSI, and 28 day compression strength pre-cast concrete. All castings used to construct the pre-cast concrete tankage are monolithic units with external and internal walls incorporated into each section.

Final Clarification Chamber (Tertiary Treatment)

The final chamber, the Clarification Chamber consists of 5 functionally independent zones operating together to provide satisfactory settling and clarification of the equalized flow. An inlet zone is provided and shall dissipate transfer turbulence at the flow inlet of the Clarification Chamber. Its performance shall also eliminate turbulence in other zones of the clarifier. Liquid is hydraulically displaced from the hopper walls and return these solids via the inlet zone to the Aeration Chamber. As solids are removed, liquid is displaced to the hopper zone of the clarifier. In this zone, settling by gravity takes place. Three of the four sidewalls are slanted to form a hopper which directs all settled material back to the sludge return zone. Clarified liquid from the hopper zone is displaced into the final settling zone to provide additional clarification of the liquid. The liquid is finally displaced to the outlet zone for final filtration and discharge from the system. Non-mechanical equalization of the flow, through all 5 independent zones, provides optimal settling and clarification.

Mechanical Aerator

Each Model 960 Singulair Aerator is installed in a concrete aerator mounting casted above the Aeration Chamber. This includes plated mounting brackets, moisture resistant electrical connector, fractional horsepower motor, flexible drip shield, restricting molded plastic foam, stainless steel aspirator shaft and a molded glass-filled nylon aspirator. Only the stainless steel aspirator shaft and molded nylon aspirator shall be installed in contact with the liquid. There is no submerged electrical motors, bearings, or fixed air piping in the aeration system. Singulair aerator motors are designed not to exceed the motor nameplate rating when installed and operated as recommended for the system. The fractional horsepower aerator motor is equipped with a restricting foam to protect the motor against high water and foam.

Fresh Air Venting System

The fresh air supply for the Singulair system is provided through a molded plastic vent assembly cast into the concrete access cover above the aerator. Fresh air is drawn into the vent assembly through slotted screening ports molded into the vent body and circulated through the drip shield into the aerator intake port. The fresh air is drawn down the hollow motor shaft through the intermediate and stainless steel aspirator shaft for infusion into the liquid through the molded nylon aspirator. The plastic aerator vent assembly is an epoxy-joined, two-piece assembly that eliminates the possibility of cap loss or removal. The concrete access cover weighs in excess of 75 pounds to discourage unauthorized access.

Bio-Kinetic® System (Tertiary Treatment)

A Bio-Kinetic® System is installed in the system mounting cast above the outlet zone of the Clarification Chamber. Each Bio-Kinetic® System provides non-mechanical flow equalization through all plant processes including Pretreatment Aeration, Clarification, tertiary filtration, chlorination and dechlorination to insure acceptable treatment results. The assembly is supplied with locking lugs and a removable cover; which consists of a Design Flow and Peak Flow micronically molded filter, baffled perimeter settling zone, non-mechanical flow equalization, flow distribution deck, lifting handles, level indicator adjustment lugs, optional chlorination feed tube, unbaffled perimeter settling zone, solids contact zone, vertical inlet zone compartmented settling zone with 37 baffled chamber plates, effluent stilling well, final discharge zone adjustable outlet weir, optional dechlorination feed tube, outlet zone, sealing grommet and discharge flange with stainless steel locking clip.

All components are manufactured from inert synthetic materials, rubber or corrosion resistant stainless steal, assembled in circular fashion and connected to a plastic outlet coupling. The outlet coupling accepts a 4" diameter, Schedule 40, PVC discharge pipe. Each Bio-Kinetic® System is installed in a vertical position so that the inverts of the design flow equalization ports are located at the normal liquid level of the clarifier. If intermittent flow rates exceed the capacity of the design flow ports, flow will be held upstream until the intermittent flow dissipates or continues to increase. If the intermittent flow continues to increase it may reach a pair of sustained flow equalization ports. With four ports in use flow through the system increases while continuing to provide non-mechanical flow equalization to all upstream and downstream processes. Peak flow equalization ports are supplied but should not be required in a properly sized system.

Flow Equalization

The wastewater treatment system includes a non-mechanical, demand use, flow equalization device. The device controls normal residential flow rates and reduces typical residential flow surges (e.g. shower at 10 minutes duration, bathtub discharge at 5 minutes duration, clothes washer discharge at 2 minutes duration, and dishwasher discharge at 2 minutes duration). The flow equalization rate shall be dependent on the specific loading pattern and the duration of flow surges. At the NSF Standard 40 design loading schedule, minimum performance of the device will equalize daily flow an average of 44%.

Bio-Static® Sludge Return

A Bio-Static® Sludge Return is installed in the cast-in-place opening(s) in the Aeration/Clarification Chamber wall to provide positive return of settled solids. Each Bio-Static® Sludge Return is located such that inlet end invert, in the Aeration Chamber, is mounted one inch below the invert of the design flow equalization ports in the Bio-Kinetic® tertiary treatment device (submerged one inch below design flow liquid level). Aeration Chamber hydraulic currents that enter the sludge return(s) are directed through the Bio-Static® device into the second zone of the Clarification Chamber. The hydraulic current containing the settled and re-suspended sludge is directed through the Clarification Chamber inlet zone and returned to the Aeration Chamber. The Bio-Static® Sludge Return will accomplish re-suspension and return of settled solids without disturbing the clarified liquid in the final settling zone and outlet zone. Each Norweco Bio-Static® sludge return is manufactured from inert synthetic material and be permanently mounted in the aeration/Clarification Chamber wall without separate external fasteners or mounting brackets. Each sludge return is a passive hydraulic device with no moving parts.