The Essential Element, a Hopewell, N.J.-based company, has put “off the grid” on the radar. The company’s combination of new technologies in water purification and energy generation has led to the creation of HYDRA, a 20,000-gal-per-day water purifier the company claims is the first self-sustainable, portable water filtration system. Photo: Essential Element The HYDRA features 12 solar panels that produce 2.88 kW to power the 16-ft-long assembly, which can be transported in a truck bed or on a utility trailer. div id="articleExtrasA" div id="articleExtrasB" div id="articleExtras" In their regular jobs at Oil Free Now LLC, Woodbury, Conn., David Squires and
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.