Shower drains, dirty dishwater and laundry could be on the cutting edge of energy efficiency and recycling.
Around the world, and more lately in the U.S., cities are recognizing that the water leaving our homes and offices–specifically, warm and hot wastewater—is an astoundingly powerful source of energy. One estimate is that Americans flush 350 billion kilowatt-amount of heat energy from the water into the sewers annually —roughly sufficient to power 30 million U.S. houses. Cities are taking notice, and taking the time to put in sewer heat recovery systems to get a piece of that energy source.
The technology is simple. Wastewater, which consists of everything gets flushed down toilets from residential buildings as well as commercial buildings such the function rooms in Melbourne CBD. This water is mixed with millions of gallons of hot water from dishwashers, showers, washing machines, and more, keeps a fairly steady temperature since it travels through sewers to the treatment plant–normally about 60°F (15.6° C), although this varies by geography and season.
In a drainage heat recovery system, a heat pump can be used to capture the heat of wastewater and move it to the clean water flow that is entering houses and businesses. All of it operates as a closed-loop system, which means that the dirty water never touches the water that we use. But the warmth of the sewage water aids heats the water that is subsequently used in washing machine washing machines, dishwashers, or even in radiators to assist heat buildings.
The trick of the system is that it requires a lot less energy to heat 60°F water compared to heat cold water. And in the summer, buildings with sewage heat recovery methods may undo their heating pumps and utilize the 60°F-sewer to dissipate excess building heat, and reduce the costs of cooling or heating the air indoors. This is exactly the manner that geothermal heat pumps can help decrease both construction heating and cooling costs by tapping to the moderate, constant heat of the Earth. But irrigation systems for energy infrastructure need expensive and disruptive digging, deep beneath buildings to pipe up to the planet’s heat. By comparison, “sewer-thermal” systems to harvest the artificial heat from shallow underground pipe systems which already have been built.
In Chicago, where the Metropolitan Water Reclamation District had been Struggling to cut costs, a sewage heat recovery system went online in May. The Chicago system prevents its own energy out of effluent, or treated wastewater, instead of raw sewage. (Associated Interactive Map:”The Global Electricity Mix”)
In midwinter at Chicago, the water leaving the treatment plant is a relatively continuous 55°F (13°C), even if the air outside is considerably below freezing. And heating and cooling Kirie’s buildings utilizes only 2% of the potential energy from the effluent, so there is a lot of energy savings that was done by using the wastewater as one of a good example of renewable energy sources, as a heating source for nearby buildings—not just in the water treatment facility.
Spreading the Word
The achievement of sewer heat recovery systems has won newfound admiration for the role wastewater can play in addressing the world’s energy barrier. It has been joked by someone from the industry that most people are not willing to shake hands with those in the sewage business. People have long associated those in the sewage business to either do repairs on the pipelines or as a blocked drain plumber. However, recognition towards the progress of reusing heat energy from the sewers has been on an incline by the people who matters.
Most local governments are eager to give it a go. When King County, Washington, that includes Seattle, held an informational session for developers, it had been said that two years back, nobody had known about this heating energy potential from sewers. However, on meetings, people are now becoming more and more curious about the process that comes with it. It is predicted that there will be massive attention from real estate developers to tap into the huge array of pipes filled with warm water. As a comparison, Seattle has 250 miles of pipes underground ready to be used.
To turn that resource into something useful is much more difficult, though. The county is still attempting to determine what exactly it means to offer you programmer access to its sewers and exactly what kinds of paperwork which would entail. Developers say they need more precise data about the temperatures of this system and the way they vary from place to place and from hour to hour.
A way to simplify the process is to catch the wastewater energy circulating under and inside each building in the city, encompassing all types of buildings including big buildings and specifically big buildings such as the Melbourne stadium. This is done without venturing into constructing a system which would involve the public infrastructure under city streets.
One system has been designed for installation in individual buildings, rather than on or near a city-owned property, so it captures heat from wastewater moving down drains even before it leaves the building. At this point, the wastewater heat is a much greater source; because of construction insulation, the wastewater is about 70°F (21°C). It has been thought that 50 percent of energy from buildings go to air-conditioning or heating. The other 50 percent goes down the drain. One firm now set up a system at a set of townhouses at Vancouver that reduced their energy usage by 75 percent and helped the growth earns of LEED Platinum, the highest rating in the internationally recognized certification system administered by the U.S. Green Building Council.
But sewage energy recovery is progressing in baby steps instead of major strides. For example, Brainerd, Minnesota, a town of 13,000, 2 hours north of Minneapolis, has measured the temperature of its sewage outflow in an attempt to quantify how much energy it has in its disposal, however, the project’s currently sitting dormant. No million-square-foot improvements here–yet.
An insider claims that the industry will need to progress a few more demonstration projects to show that the technology can work in several distinct geographies and environments. And she and other supporters of this technology might need to do a whole lot more work to educate the general public about the surprising potential of filthy water as a supply of clean energy. The drains are becoming less associated with a sewer blockage, unpleasant odour, and brown, dirty water.