HOW DOES IT WORK?
AN OVERVIEW OF ECOLOGICAL WASTEWATER TREATMENT
Primary effluent enters a series of reactors where secondary treatment is achieved. Here soluble organic waste is converted into living biomass. Plant roots in the hydroponic reactors trap suspended solids and provide a diverse scaffolding for bacteria, fungi and micro-organisms. In these reactors the processes of nitrification and denitrifaction take place.
Within the polishing wetland water flows through small voids within a matrix of soil, gravel and growing roots. Remaining nutrients and organic material become trapped within this matrix and are transformed into rich soils and fast growing vascular plants.
One of the benefits of ecological treatment is robustness, mechanical simplicity and ease of operation. A well-run system typically takes between 3-10 hours per week of attention and maintenance. This time includes wastewater sampling, maintenance of mechanical systems as well as seasonal pruning of plants. These tasks are typically performed by a specially trained member of the maintenance staff.
The ecological treatment process begins with primary treatment and flow equalization. Solids, fats, oils and greases from domestic sewage are retained within the septic tank and primary effluent is pumped on to the next stages of treatment.
After the aerobic reactors treated water is clean and free of odors but its not yet clean enough for re-use. The clarifier is the first step of the tertiary treatment process. In this conical tank, suspended solids and bacteria group together and settle to the bottom where they can be retained in the secondary reactors. Clean and clear effluent flows by gravity to the polishing wetland.
Mechanical filtration and disinfection are the final steps in tertiary treatment. Water from the wetland is pumped through fine cartridge filters. Bacteria and pathogenic organism are then sterilized by high intensity ultraviolet light or chlorination. This water has now reached swimming water quality and is safe for re-use.