Miami Green Homes

Water and wastewater (WWW) treatment – a look at the energy used for water in the US

While water and wastewater (WWW) treatment accounts for a surprising 5% of total U.S. electric power generation, topographically-variable WWW conveyance account for a more surprising 15% of the same total [Pod06; Coh04]. In addition, while wastewater contains energy in dilute form, current goals for recovering such energy represent only 0.02% of the total generation, through the use of microbial fuel cells of the future [Log04]. If, on the other hand, WWW were decentralized, up to 15% of total U.S. electric power production could be saved.


While centralization of WWW treatment was implemented to concentrate resources and ensure water quality, today many monitoring, quality control, and operation and maintenance (O&M) functions can be decentralized electronically. Imagine, if each building of the future contains a direct potable reuse system, then maintenance personnel, rather than driving to a central facility daily, would be dispatched electronically to neighborhoods for routine annual maintenance. Moreover, decentralization would increase the accountability of neighborhood residents in terms of responsible use of water, personal care products, and household chemicals.


Beyond energy savings, autonomous net-zero water (ANZW) buildings would not need to treat for most pesticides (US, 5 billion lbs/y) and industrial chemicals (US, 6 billion lbs/y), representing a total mass loading of 2 mg/L on U.S. surface and groundwater runoff. Treatment instead would focus on effective destruction of endocrine disrupting compounds (EDCs) such as pharmaceuticals, which cannot be as easily regulated in terms of environmental half-life as pesticides and other chemicals, by advanced oxidation. This latter advantage would address the current 6% feminization of male fish across all species (20%, black bass) in U.S. river basins [Hin09]. Finally, an urban demand for e.g. one million gallons of water every day in Southeast Florida would be removed from the (Everglades) natural system. Eliminated would be water rationing, and the need to treat seawater with total impurity levels two orders of magnitude higher than drinking water standards, to drinking water standards when impurities in treated wastewater e.g. in S. Florida currently meet 87 of the 93 numerical drinking water standards on average without further treatment.


Increased construction activity in the outlined areas over the last 10+ years. Many infill projects and zero lot line developments. Increased population growth in the target area with increased load (people) and demand (use per individual). Overall individual load has increased over X years by X gallons per day. Strain on water treatment system and infrastructure, especially close to water ways cited. Septic tanks systems that are undersized, outdated or broken, without eh owner knowledge. Purposeful (non permitted or documented) re-routing of sewage water to nearby water ways and excess burden on municipal sewer system with surface water runoff, increased rainfall intensity and more man-made diversions of water. Quantity of subsurface runoff (stormwater).


Estimates of water use in the United States indicate that about 410 billion gallons per day (Bgal/d) were withdrawn in 2005 for all categories summarized in this report. This total is slightly less than the estimate for 2000, and about 5 percent less than total withdrawals in the peak year of 1980. Freshwater withdrawals in 2005 were 349 Bgal/d, or 85 percent of the total freshwater and saline-water withdrawals. Fresh groundwater withdrawals of 79.6 Bgal/day in 2005 were about 5 percent less than in 2000, and fresh surface-water withdrawals of 270 Bgal/day were about the same as in 2000. Withdrawals for thermoelectric-power generation and irrigation, the two largest uses of water, have stabilized or decreased since 1980. Withdrawals for public-supply and domestic uses have increased steadily since estimates began.


Quick Pros & Cons of LEED Certification and Green Building in South Florida

Green Certification in Subtropical climates, such as South Florida, has many pros and cons and making the decision to go green can be a difficult but fruitful one. The heat in the summer and the pounding sun throughout the year make air conditioning here a basic necessity. Power bills are generally much higher than elsewhere in the continental US and the intense sunlight  also damages building facades and roofs faster than if in a temperate zone. The Subtropical sun is also more intense contributing to the heat island effect. The sun is not the only challenge a Subtropical climate faces, but high humidity brings with it mildew and mold into homes and requires special treatment of building materials and construction practices. Finally, frequent and heavy winds accompanied by plenty of rain can easily damage more fragile building materials. Stormwater management must be addressed even on small projects. The Florida Hurricane Code tests building wind loads and sets minimum standards. This is set under the Florida Building Code: Test Protocols for High-Velocity Hurricane Zones.

The Monetary Gain/Loss Factor

When deciding whether or not to pursue certification, one item to consider is whether increased operations cost will outweigh the initial investment. Is it worth it to you? Replacing appliances and other fixtures has sometimes a larger initial cost, but the benefits can include lower energy and water bills.

In LEED(R) for New Construction and Major Renovations there are many points that are easily ontained with little added cost. In the Sustainable Sites category, there are several credits based alternative transportation methods. Creating space forbicycle storage and changing rooms with showers and having access to public transportation are simple additions in the scheme of a large design. Other attainable points can be found in the category of Materials and Resources. In this category, using regional materials (materials from within 500 miles of the site) can actually lower the cost of construction by minimizing transportation costs. Material reuse on site is also beneficial and lowers your costs.

Some of the more costly credits fall under the category of Energy and Atmosphere. Solar panels start at around $1.00 per watt and creating a medium sized grid connected system for a home can run around $40,000. Most states, however, offer a 30% federal tax credit for using solar power. The initial cost is much higher, but when performing a life cycle cost analysis, the payback can begin after 10 years or so (depending on the size and power of the grid). When considering solar power, there are a few things to think about.

1. How many kilowatt hours a month do you use? You can find this on your electric bill.

2. Where do you live? In this case, South Florida. The amount of sunlight and the intensity of the sunlight make solar panels ideal. If we were in Russia, the frozen tundra with little to no sun,, solar panels might not pay back as much, if at all.

3. Where will you be installing the panels? A south facing roof is best.

4. How much of your electric bill will you offset with solar? i.e. How many panels and how much payback would you like to see?

5. What other upgrades can you complete to achieve the maximum solar power benefit (such as increasing insulation, reducing electrical load demand and upgrading windows and doors for better weatherization).


This website provides information on solar power pricing, installation, and use.


The Tax Factor

Many states offer tax credits to those who follow green building principles. These tax credits are given based on initial costs for the most part. Some credits include 30% pay back on expenses made for EnergyStar appliances and 30% on cost of solar panels. These federal tax credits have a tendency to change very year so an internet search for your local credits is recommended. In Florida, there are many credit options available. This site contains a list of Florida incentives and policies, as well as other states:


The Exposure Factor

Large corporations such as Radio Shack and FedEx are converting their headquarters to LEED certified buildings. Why? Not only for lower long run operating costs, but also for media exposure. A headline stating that “So and So Corporate Headquarters Achieves LEED Certification” or “Sustainable and Environmental Awareness by So and So Corporation” sheds  good light on the company to the public or good “corporate social responsbility”.. Larger buildings achieving LEED certification makes the company, the builder, the architect and all involved feel good and recognize the team as conscious of their environment. With all the news of global warming and destruction of rainforests, wildlife, nature, etc., LEED certification provides a company with the upper hand on environmental marketing.

In South Florida, energy efficiency and green building is increasingly common, and creating a greener city is a government objective. In Florida, there are 450 LEED certified buildings, 34 of which are in the City of Miami. There are also 177 registered projects in Miami. They range from a parking garage, to a corporate headquarters, to university buildings. The broad range of LEED projects in Miami are creating a well-rounded green city. The exposure is not just something for the parties involved but also for the City and  the State. It has become a country wide effort to “LEED-ify” the way we build, reduce our emissions and protect the environment.

With these sites, you can see what LEED certified buildings are around you, as well as the registered projects.


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