GROWING CLEAN WATER

If you Google “Sustainability,” or even “Net Zero Sustainability,” the majority of the information that surfaces relates to energy – electrical power. Yet the biggest issue we face on the physical side of sustainability is food. And food production consumes the vast majority of our fresh water. Here are excerpts from a small book that provides a perspective and some processes for ensuring that we have an adequate supply of fresh water. The book provides examples of applications at different scales … a small community, an office with 5,000 employees, and a single family home.

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GROWING CLEAN WATER

B.C. Wolverton, Ph.D.

and John D. Wolverton

 

The 21st century will feature buildings having their own microenvironments with natural ecosystems to treat waste and purify the air. Less than 0.1 percent of all available fresh water remains for lakes, creeks, streams, rivers and rainfalls.  The supply and demand for water dictates that water reuse becomes a more integral component of water conservation measures.

There are many uses for water that do not require it to meet drinking water standards. Making use of treated or partially treated water before release to receiving streams or holding ponds must become common practice.  Nature has proven its innate ability to cleanse itself.  The harnessing of these powers is a use whose time has come.

Integrated Pest Management (IPM) involves the use of a wide variety of methods to control pests, including natural predators and least-toxic controls. For example, Disney World has successfully reduced the use of toxic pesticides by 70 percent through the use of IPM.

Encouragingly, the two fastest growing industries in the U.S. are organic farming and alternative or preventive medicine. Organically grown foods are certified as having been produced without the use of pesticides or synthetic chemicals.  Alternative medicine advocates increasing the body’s resistance to diseases through diet, lifestyle changes and dietary supplements (vitamins, minerals and herbs).  Persons in the Far East have used many of these practices for thousands of years.

Further studies have shown that aquatic plants, such as bulrush, cattail and reed, excrete a variety of substances that act as bactericides, fungicides and algaecides. While substances excreted from plant roots kill pathogenic bacteria, they are not harmful to microflora commonly found in the rhizosphere.

Domestic wastewater can serve as a complete hydroponic fertilizer for growing cherry tomatoes and green beans, but that tertiary level wastewater treatment resulted after only seven days. Phytotechnologies can be viable wastewater treatment options while producing valuable by-products, such as crops, animal feed or raw materials for industrial manufacturing applications.

Nature has provided the means to treat our waste and awaits man’s ingenuity to engineer nature to meet his needs. Natural wastewater treatment provides a safe, economical alternative to conventional engineered systems.

Primary treatment takes place in a septic tank where solids settle to the bottom and only the odorous liquid flows out of the tank. If the household uses a garbage disposal, then two septic tanks in a series are recommended to ensure that solids do not enter the rock/plant filters.  The rock/plant filter is basically a hydroponic or soil-less treatment method.  The literal translation for the term “hydroponic” means “water working.”  Perhaps a more succinct term for this system is “phytoponic,” meaning “plants working.”

Dimensions of rock/plant channels determine the degree of purification of effluent. Channels having a water depth of 12-inches or less;  a rock cover that is 4-6 inches above water level;  and a retention (contact) time of 48 hours or greater can achieve tertiary level treatment.  The treated rock/plant filter effluent can then discharge into a sand filter where it is slowly absorbed into the soil.  Because the effluent at this point is clean, it does not cause any environmental harm.  A more ideal method is to use the effluent for irrigation of landscaping or gardening plots.

Installers have failed to properly read the elevations to provide gravity flow and have used rocks that are too small, resulting in filter clogging. Rocks need to be at least 1 – 3 inches in diameter.  Others have designed systems that were too small for the waste flow.  Retention time is a key factor in properly treating wastewater.

As a part of its “good neighbor” policy, NASA scientists designed a rock/plant filter system for a mobile home park. At installation, the park housed 17-20 mobile homes, but could accommodate more.  A public Laundromat was later added without provisions for the increased water flow and lint removal.  This impacted the system and has further led to surface pooling.  However, lush vegetation completely covers the first cell so that excellent treatment continues.

Thanks to the U.S. space program, this process of wastewater treatment is rapidly emerging as the treatment method of choice for small towns and communities. Primarily due to land constraints, large cities must continue to rely upon mechanical treatment technology for treatment of their waste.  When utilized to its fullest potential, this natural technology can convert an expensive human and animal waste disposal problem into a renewable process for growing valuable animal feed, organic fertilizer, biomass for energy and raw materials for industrial manufacturing processes.

The first large-scale operating systems using aquatic plants to treat domestic sewage and laboratory wastewater were installed at NASA’s John C. Stennis Space Center in Mississippi in 1974. By the mid 1970s, aquatic plants such as water hyacinths, duckweed, bulrush and water iris treated all the wastewater at this facility, home to approximately 5,000 employees.  For more than twenty years, NASA has used this cost-effective, natural process to treat all of its wastewater, thereby saving taxpayers millions of dollars.  These simple plant systems work as well or even better today than they did when they were installed.

For plant survival, it is important that plants are acclimated to seasonal temperature variances.

During the next few decades, marsh systems will produce another substantial benefit – a cash crop. In addition to treating domestic wastewater, these systems produce massive amounts of plant material.  Plants, such as duckweed, can be harvested, dried and sold as organic fertilizer or animal feed.  Some municipalities will come to realize that their natural wastewater treatment systems not only operate at a fraction of the cost of a mechanical system but can also provide much needed revenue.

In the Wolverton home, a hydroponic modular planter system sits along the interior of the exterior wall of a sunroom, and services four main functions: aesthetics, air purification, wastewater treatment and humidity control.  The only source of water and nutrients for both plants and microbes is waste from the bathroom toilet.  Any excess wastewater flows through the planter modules into an overflow system outdoors, where further treatment is accomplished through landscaped plantings and eventually flows into a fishpond.  The system has performed flawlessly for ten years.

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Your ability to use this technology will vary with your situation. If you live in a hi-rise apartment in New York City … your only gain may be “awareness.”  But if you’re in an environment in which you can influence your wastewater treatment, then this approach may be useful.  However, if individuals here and there begin applying these natural systems for producing fresh water, it’ll make a huge difference for all of us.  (This small, inexpensive book is also available via Amazon.)

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