Dredging in NYC Coastal Waterways Results in a State Park

The idea of dredging is not a new one, but the results of those efforts to recycle what is dredged largely goes unnoticed. Dredging occurs on our coastal waterways in order to combat erosion and urban runoff that changes the landscape of regularly used shipping lanes in our oceans. Dredging is even used offshore from beaches, such as in North Carolina, to replenish a reshaping beach line that threatens our recreational and living habits.

First, it is important to understand that dredging is the removal of sediment that settles in gullies in the ocean as tides and waves change the general shape of the bottom of the ocean. Furthermore, the dredging of navigation channels, approach channels, berths at marine terminals and marinas has been happening in some coastal cities, such as New York, since the 19th century. While technology may change to increase efficiency, conscious companies are now concerned with the environment.

A huge push to recycle dredged sediment has happened in the last couple of decades. Most often, reusing dredged material is a challenge due to contamination from the absorption of spilled chemicals and heavy metals in the waterways. This makes management of dredging expensive at times.

New York City is one of the places along our coastal waterways that actively seeks to recycle our recovered sediments through landfill reclamation, habitat restoration, and beach replenishment. But, in the 1990’s, the dumping of dredged materials ceased and innovative ways to reuse the sediment became an economic priority.

Prior to 2009, NYC successfully completed a pilot project that mixed dredged material with Portland Cement in order to create a “contour layer” over a landfill at Pennsylvania and Fountain Avenue in Brooklyn. Nearly one million cubic yards of processed material was later successfully laid down at Fresh Kills landfill transforming it into a 2,200 acre public park which is three times the size of Central Park.

NYC residents and visitors alike can now enjoy another park that is critical to an environmentally safe practice becoming a benefit rather than a burden.

Wastewater Treatment Reaches Energy Net Zero in Oregon

Imagine a wastewater treatment plant that consumes more waste than it does energy and leaves an excess that equals half a million dollars in savings for its citizens. Such a place does exist and carries the designation Energy Net Zero. One place in particular is Grisham, Oregon.

Through above par water resources engineering, the plant does even more than that. It also recycles its fats, oils and grease which are transported to local establishments. And, they get tipped for it generously, increasing the pool of available monetary resources for future development. All those savings go into making the plant the most resourceful wastewater treatment plant possible.

Fortunately, like with most wastewater treatment plants, the sludge that forms from settled particles in the water can be converted to a biogas. The biogas produced from wastewater treatment is then fed into two cogeneration engines that generate heat and electricity – not only sustaining its own operations, but supplementing the city’s needs as well. Treating 13 million gallons of wastewater each day, the plant meets the water needs of 114,000 customers.

The concept of Energy Net Zero is the goal of any environmentally-conscious water resource engineer. While Oregon is the not the first to generate electricity in excess of its wastewater treatment in America, it is the first in the growing Pacific Northwest. It is worthy of celebration and recognition because it is a step in the right direction for a self-sustainable society.

Zero net energy is also common in the corporate world where companies like Melaleuca, devoted to natural health, maintain buildings that produce more electricity than they use. This is considered renewable energy that reduces the carbon footprint of any corporation that embarks upon this noble mission.

Achieving net zero energy consumption has been proven to be possible now and sets a true precedent for wastewater treatment plants across the nation. New York City boasts such a plant with the goal of net zero by the year 2050. More cities are in the process of adopting similar plans.

If you are looking for wastewater treatment bids, go to h2bid (www.h2bid.com) for the largest listing of wastewater treatment bids.

Creating Water Power From An “Artificial Leaf”

The idea of separating water into hydrogen and oxygen has been around for some time. Often dismissed as impractical, such a fuel source could provide clean, sustainable energy for our world if it could be made to work reliably and efficiently. One Harvard scientist has made great strides toward making that dream a reality. Daniel Nocera, the Patterson Rockwood Professor of Energy at Harvard University, has refined an “artificial leaf” that has the potential to revolutionize the way we produce energy.
The artificial leaf has been sought after by scientists for decades; an efficient device that, like plants, can use sunlight to create energy. But where plant leaves produce sugars, artificial leaves would split water into clean-burning fuel. Some prototypes had been developed in recent years, but these devices had a weakness: the water had to be pure. In the absence of distilled, pure water, bacteria would grow and form a film over the device, halting hydrogen and oxygen production. This weakness was a major barrier in making the technology practical, given that much of the world does not have access to clean drinking water, let alone ultra-pure water.

Dr. Nocera has developed the world’s first practical artificial leaf and his findings indicate that his design is able to self-heal and to work even in dirty water. In presenting his work at the recent American Chemical Society meeting in New Orleans, Dr. Nocera says that he’s developed a cobalt-based coating that breaks off during the gas-producing reaction and then slowly reassembles back onto the silicon wafer. Because it’s constantly re-forming itself, the bacteria don’t have an unbroken surface to stick to – which makes the new and improved artificial leaf a more rough-and-ready device that can be deployed even in dirty water.

Nocera’s artificial leaf is elegantly simple: It’s a coated silicon wafer roughly the size of a credit card that can be dropped into a cup of water. When the wafer is placed in sunlight, pure oxygen will bubble up from one side and pure hydrogen from the other. Such a device, placed in a bucket (and with the two sides properly separated, of course) could create enough clean fuel to power a home in a developing country.

Such a device could radically revolutionize clean energy, reducing dependence on fossil fuels and providing an even better solution than plain old solar cells, which are perfect for sunny days but don’t store energy for nighttime use. In addition, it would allow for onsite power generation in virtually every region where people live. Such power could be used not only to light homes, but it would also be critical in pumping fresh drinking water and assisting in local sanitation needs. The lack of reliable electrical power is a key barrier to water and sanitation worldwide.

Dr. Nocera admits that there are limitations. While his energy-to-fuel system is currently around 70% to 80% efficient, Nocera said, it’s only as good as the silicon-based solar underlying it – and given that current solar cells have an efficiency rate of 7%, that means an overall rate of about 5% for his artificial leaf. But Nocera expects solar cells in general to vastly improve over the next few years.

While it will likely be a few years before artificial leaves are field tested, the technology is exciting and offers the promise of reliable, clean energy in even the most remote locations. This invention certainly adds to the clean energy “toolbox” and increases the likelihood that one day, people worldwide will have access to electricity and sanitation.

Nocera notes that his research was aided in funding from the National Science Foundation, the Department of Energy and the Air Force Office of Scientific Research.