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The Sound Economics of Wastewater Gardens®
Cost reduction and longer life-time
- While initial investment and installation of WWG unit/s may be higher than some conventional mechanical or chemical systems (or up to 50% lower), depending on the country and on the type of plants chosen (mature or budding at start of WWG operation), WASTEWATER GARDENS® operating and maintenance costs are typically 5-10% those of high-tech, mechanically based sewage treatment plants (STPs *).
* There are different types of conventional STPs (Sewage Treatment Plants), including Extended Aeration Biological Systems, Activated Sludges, RBC, and Hybrid systems, with a different cost for each system.
For example: Extended Aeration Systems costs around 15% less that Biological Systems in installation, while running costs are typically around 10 times more expensive. |
- While different types of conventional STPs have varying initial capital costs and maintenance expenses, all have much higher operating and refitting/repair expenses (conventional STPs typically need refitting after 5-10 years of service).
- WASTEWATER GARDENS® have a life cycle of minimum 20 years, which is 2-3 times that which might be expected of an STP, especially in tropical conditions; most conventional sewage treatment systems will have a lifetime of at best 10 years, after which time significant or complete parts replacement must be considered.
- Being natural systems, there are no monthly and/or yearly costs of expensive chemical additives, while WWG systems also provide insurance against inflation of maintenance costs (parts, electricity, service, chemicals, etc.).
- WWG systems are designed to rely completely on gravity-flow, with little or no machinery being used; costs of pumps, electricity, replacement of parts and technician labor for maintenance are removed, unless natural gravity doesn't allow free flow of water.
- In addition to sewage water treatment and ability to release into the environment purified water, the WASTEWATER GARDENS® can supply part or all of the landscaping needs without need of additional potable water or fertilizer - part or all of the landscape being watered by otherwise wasted water -, which in some sites can represent significant financial savings.
- The discharge water from the WWG being much lower in organic compounds (BOD) and suspended solids, problems with important quantity of water having to be released into the environment, with attendant problems of soils absorption capacity in the leachfields, are greatly reduced ; WWG discharge water will much less likely clog soils and leachdrains remain effective for a much longer time, sometimes indefinitely.
Using Wastewater Gardens® as an economical incentive
- Wastewater Gardens® can be a low-cost and effective solution by providing a sustainable solution to the problem of how to deal with sewage by generating useful and saleable products from the effective use of the wastewater. The "sludge" (solids pumped from the septic tank) can be composted, which kills any potential pathogenic bacteria, and will produce beneficial organic fertilizer. The constructed wetland and secondary subsoil irrigation can be used to grow crops such as fast-growing timber, cut flowers, medicinal plants and herbs, fiber for handicraft manufacture and fruits.
- Wastewater Gardens® can also be created to deal with sludge from septic tank pumpout trucks. Constructed wetlands have been shown to be effective in utilizing this material which otherwise is expensive to treat and dispose. This service, combined with the use - or sale - of compost and the harvested products grown on the WWG, can help defray the costs of construction and operation of a treatment system such as Wastewater Gardens®.
- Wastewater Gardens® are built with local labor and local materials rather than importing expensive machinery and/or chemical products. Thus both initial capital investment and operating costs reflect and contribute to local, regional and national economies.
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