Domestic Wastewater Management

Reed Beds and Constructed Wetlands

Often referred to as zero discharge systems, reed beds and constructed wetlands wastewater treatment systems are used to treat wastewater from small developments. Reed beds are usually gravel-based systems where the wastewater flows vertically or horizontally through the mass of reed roots. Constructed wetlands describe the soil based system where the wastewater flows over the soil substrate.

In both cases, effluent trickling through the systems is cleaned by microorganisms living on the root system and in the litter. These organisms utilise the sewage for growth nutrients, resulting in clean effluent. The advantages of these systems are:  

  • Easy management

  • Low running cost (although potentially high cost of installation)

  • Excellent reduction of solids from septic tank

  • Can be used with old systems to enhance effectiveness

  • Secondary benefits for potential wildlife habitats

  • Potential for removal of large range of pollutants

Potential Problems in Wastewater Management Systems

Poor design and installation of systems can result in major issues including:

  • Surface water pollution

  • Groundwater contamination

  • Odour nuisance

Problems may be caused by one or more of the following:

  • Inadequate permeability of soil

  • Absence of percolation areas

  • Septic tanks connected directly to a watercourse

  • Poorly designed, constructed or installed septic tanks

  • Inadequate maintenance of systems

  • Connection of rainwater or surface water to septic tank

  • Not connecting baths and other household appliances to septic tank

The key to installing a reliable on-site system, that minimises pollution, is to identify a suitable treatment system following a thorough site assessment.

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