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Tertiary treatment residential


Tertiary systems provide additional treatment to the effluent emitted from secondary treatment systems.  Essentially, a “tertiary” or “polishing” stage is added to raise the effluent quality before it is discharged to the receiving environment or reused for beneficial purposes.

Tertiary systems are designed to enhance removal of organics, settled solids, nutrients and pathogens discharged from secondary treatment systems.  The treatment standards to be achieved by tertiary systems are dependent on the sensitivity of the receiving environment, water reuse criteria, and local regulations.

Tertiary systems are often deployed to mitigate potentially adverse environmental impacts or to overcome extreme site restrictions.  They allow responsible, fail-safe development of marginal properties.

Anua has multiple secondary treatment system options which can be coupled with the Puraflo Peat Fiber Biofilter as a tertiary polishing filter.

Benefit statement

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  • High level treatment suitable for reuse applications
  • Protects surroundingenvironment and groundwater resources
  • Significant reduction in size of soil dispersal area (where applicable)
  • Can aid planning application process for sensitive or restricted sites
  • Provides responsible development for pristine areas
  • Quick and easy installation can minimize disturbance to mature sites/areas

The Puraflo peat fiber biofilter system is the most versatile and reliable treatment system on the market. The system is sustainable and uses little to no energy. Puraflo is odor-free and operation is very simple. Puraflo’s flexibility coupled with performance is unmatched in the industry.

Suitable applications

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  • Small or restricted sites
  • When discharging to marginal soils
  • When discharging to environmentally sensitive receiving waters
  • Sites located in close proximity to potable water wells, aquifers, wetlands, or surface waters
  • Locations where the existing system needs to be upgraded or retrofitted


How it works

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The PurafloTertiary Polishing Filter Process

1. Collection and Pumping

Effluent flows from the secondary treatment system into a watertight pump tank/basin.  The effluent is filtered by a Sim/Tech Pressure Filter STF-100, screen filter, or disc filter while dosing to the Puraflo modules.

2. Treatment

The liquid effluent is timed dosed at specific intervals into the Puraflo modules, where it

is distributed evenly onto the biofibrous peat media. A combination of biological, chemical, and physical processes treat the effluent as it filters through the peat fiber media.

3. Dispersal or Water Reuse

Tertiary treated effluent emerges from the Puraflo modules and disperses either into a gravel

pad directly below the modules or is collected for dispersal by other methods, including

gravel trenches, LPP, drip irrigation or other dispersal methods. Effluent is suitable for

  1. Chemical or UV disinfection may be required.


Schematics and documentation: Design information:

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Brochure: Puraflo Overview (PDF)

Brochure: Platinum Overview (PDF)

Operations and support

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Anua has the products and expertise to tackle the most extreme sites and meet the most stringent environmental regulations. Our knowledgeable team members are here to assist you.

  • Free technical support and consultation during all project stages
  • Support and interface with state/province, county/parish, township, or local regulators
  • Excel spreadsheet packages for easy design
  • Product manuals and drawings in CAD or PDF
  • Presentations, webinars, and training on products or requested topics
  • Network of local distributors throughout North America
  • Network of authorized installers and service providers throughout North America

Anua has been in business in North America for over 20 years. This longevity and commitment to product and support quality gives our customers peace of mind in a turbulent marketplace.


O&M Manual – Puraflo

Case studies

Case study – Juneau

To find out more, or to purchase our products and services, contact Anua today