It’s a cultural mind set in this country. People like their water plentiful and cheap. In a land that is rich in natural resources generally that has not been a problem in the past. However, if more isn’t done to conserve fresh water, there will be a major crisis in many more places within a very short time.

Projections are that 36 states will face water shortages in the next five years and half of the world’s population will be in the same situation by mid century. As the population continues to increase, so does the demand for more fresh water while the supply dwindles. Drought, pollution and lack of conservation are at the root of the problem.

In this country, the areas that will continue to experience the most population growth will be in the warmer, drier, southern-regions of the county, many of which are in the midst of an extended drought. Meanwhile, underground aquifers, surface-water sources and mountain snow packs are showing signs that they will not be able to keep up with demand.
Although people don’t necessarily care to use it after it is sent down a drain or flushed down a toilet, they will be forced to look at wastewater recycling and other alternative methods as part of the mix of conservation efforts if they want to live where they chose.

Innovative ways to clean and reuse wastewater have become common place in many parts of the world as well as some regions of this country; however, many areas continue to turn a blind eye to the problem or are not threatened by it because of the perception of plentiful supplies.

Mike Millard, sales engineer for Southeast Pump & Equipment, Inc., based in Alpharetta, Georgia, just outside of Atlanta, is a proponent of recycling wastewater from decentralized systems for irrigation and other non-potable uses. Such systems have been put to work in some parts of this country and in many other places in the world.

The regions in the U.S. that are experiencing the most explosive growth—from the Southeast to southwest and into southern California—are copying a pattern that Australia experienced a decade ago, according to Millard. The desirable areas to live didn’t have enough water, yet people kept moving in. They ended up rationing water and were forced to come up with ideas to conserve. The efforts paid off and now those regions of Australia are making do.

“In the United States, people use around 150-200 gallons of water per capita per day. In Australia, they’re down to 30 or 40 gallons per capita per day,” he said. “Most of it had to do with education. People have to understand there is only so much water. Once you realize that, you put a higher value to it and you don’t waste it.”

It’s being done
“If you use reuse water to irrigate your lawn through a sub-surface, drip-pipe system or to flush your toilet, theoretically without making any other changes, you could cut your water consumption by up to 50-percent,” Millard said.

The first key, he says, is to use less water. In Australia, they conserve by collecting stormwater, also known as rain harvesting. They have toilets that have one and two buttons, for liquid and solid waste, so they don’t use as much to flush.

They have dual pipe systems inside their homes, one for potable water and one for the recycle wastewater.

Black water from toilets goes into a septic tank and is filtered. An aerobic treatment unit cleans it so it can be put through drip tubing systems to water lawns. The grey water that comes out of showers and laundry can be cleaned to flush the toilet and any excess water can be also used to water the lawn.

“That’s 100-percent recycling right within a house,” Millard said.

Purple pipe
Some parts of this country already incorporate a secondary water infrastructure, which uses purple pipe to differentiate it from the potable water supply lines. A treatment plant takes in wastewater, runs it through a fine filter or membrane and then past ultraviolet lamps to sterilize it and a trace of chlorine is added. The result is a high-quality, reuse water that can be returned to homes via the purple pipe, typically to a hydrant near the driveway, according to Millard.

It’s not for drinking or showering, but could be used for a host of other purposes that would otherwise deplete the potable water supplies, such as irrigating lawn, flushing toilets, washing cars, or industrial uses.

“That concept is just getting started in Georgia. All communities built in the last ten years or so in Florida have had purple pipe run back to them. They ran low on fresh water before Georgia did,” Millard said. “They don’t bring it into the house. That is something that is coming in the future.”

A tip from nature
Millard favors treatment systems that count on nature to do most of the work of cleaning the wastewater.

“The systems we like to work with don’t look like a treatment plant. They are simply plain green tanks buried in the ground that you can plant shrubbery around and hide.

People work and play around them and don’t know they are there,” Millard said. “They are very simple, very robust, easy to operate and consistently generate high-quality water.”

The water is collected in a couple of different fashions:

• Conventional gravity with a lift station to pump it to the water treatment plant.
• With a low-pressure sewer system that have grinder pumps at each home to send it to the treatment plant through a small pipe.
• A STEP (septic tank effluent pump) system at each home that pumps the liquid waste to the treatment plant where the solid matter is settled out in a sludge tank and is eventually pumped out.

The biological process, called an attached-growth treatment system, consists of a tank that is filled with HPDE plastic media that has a large surface area. Naturally occurring bacteria attach to the media and feed on the waste in the water.

A compressor blows air through a grid in the base of the tank, sending bubbles up through the tank, mixing and aerating the media. Aeration alone would treat the waste to some degree. With the large surface area for biological growth, the process is enhanced by a factor of four, according to Millard.

“For the bacteria, their food is in the wastewater. If you feed them, keep them warm and give them plenty of air, the ­bacteria will eat up the organic and inorganic material in the waste water. You have fairly clean water coming out of the biological treatment plant,” Millard said. A small amount of sludge is produced but is dropped out of suspension after aeration and only clean wastewater leaves the treatment plant. By adding a physical barrier filter and UV sterilization the effluent can be converted to reuse quality.

“That’s a system that Mother Nature set up. All we’re doing with these biological designs is enhancing Mother Nature,” he said, pointing out that the ancient Romans incorporated the concept when they observed that wastewater could be cleaned by sending it over a rock bed. The rocks were the media for the bacteria which were energized by the aerated water to consume the waste.

Centralized vs. Decentralized
According to Millard, the EPA favors large, centralized systems in urban areas that generate large quantities of high-quality water. However, they do create some issues such as getting the reuse water back to the homes if the purple pipe infrastructure isn’t there.

“Believe it or not, Atlanta is so low on water that they have a new regulation that allows tanker trucks to go to a treatment plant, fill up with reuse water and go to somebody’s lawn and water it for them,” he said. “So instead of purple pipes, we’re going to have purple trucks running around.”

But for new developments in remote areas, he recommends getting rid of any septic systems and incorporate smaller, decentralized systems. They would be scalable and built as needed. People can hook up to a sewer system which generates reuse water. It can do everything that can be done with a big plant, just on a smaller scale.

“The infrastructure for wastewater is very expensive. So it is usually an after thought in remote areas. By using the smaller technology you can install it at a much lower cost,” Millard said. “Basically you put in a sewer plant, but it’s not huge. It’s a plant to handle just that area.”

Taking it a step further
Though the effluent from a wastewater treatment plant is not used for consumption, some areas of the country such as in California, Arizona and a few other states facing water shortages send it to a water plant for the final sterilization/purification process, making it fit for drinking.

In most communities, water is used just once. It is sent down a drain, into a sewer pipe that goes to a wastewater treatment plant where it is treated to regulatory standards. This typically results in an effluent that is as clear as drinking water. This wastewater effluent is usually discharged into a body of water like a river or lake.

Millard says this doesn’t make a lot of sense. Highly treated wastewater is dumped into a river or lake where it mixes with stormwater run off from other communities, which contains pollutants like motor oil and toxic metals, and is later taken up by other communities and processed for their potable water supply.

“What makes more sense? Piping clean, wastewater effluent to fresh water treatment plants to be used locally or dumping that effluent into dirty stream water, for someone else to draw out, clean up in a water treatment plant and drink?” he said.

“When it comes to wastewater, somebody is going to drink it again, whether it’s next week or years down the road. All water is recycled,” Millard said, referring its cycle of evaporation, transpiration, precipitation and infiltration. “Theoretically, that is going to happen no matter what. Reuse by connecting the pipes simply short-circuits the process.”

Overcoming another hurdle
“It’s called the ‘Yuck Factor.’ People have to get over the fact that reuse water is not ‘dirty’ water. It’s clean water,” ­Millard said, especially when it comes to purifying it for drinking, cooking and bathing.

The issue will be forced upon them. Whether people wish to admit it or not, there is a limited supply of fresh water and a crisis is fast-approaching. The landscape of discussion is rapidly changing as people deal with a lot of questions. What is wastewater? How is it collected, how do you reuse it, how do you save the potable water from being depleted?  

“There have been several papers written about the educational process they went through in Australia and Southern California to get people to overcome the Yuck Factor about using reuse, purple pipe water,” Millard said.

“It comes down to education.” SLDT