Posts Tagged ‘remediation’
Reactive Glass: Pollutant ‘Sponge’ for Site Remediation
Posted in Research by Kate Archdeacon on January 12th, 2010
Source: CleanTechnica via CleanEdge
Image: diego cupolo via flickr CC
From ““Swelling Glass” Cleans Polluted Water Like a Sponge“, by Tina Casey
This is the discovery that could put the College of Wooster on the map: glass that swells like a sponge. Put together like a nano-matrix, the new glass can unfold to hold up to eight times its weight. The glass binds with gasoline and other pollutants containing volatile organic compounds but it does not bind with water, so it acts like a “smart” sponge, capable of picking and choosing from contaminated groundwater.
The new material was developed by Dr. Paul Edmiston of the College of Wooster, who formed a new company, Absorbent Materials, to market the new glass under the trademark Obsorb. A number of pilot sites are being tested in the United States, and industrialized countries are not the only ones that stand to gain. Obsorb’s unique properties make it ideal for low tech, low-budget cleanups in developing areas as well.
Obsorb is a reactive glass. Unlike conventional glass, it can bond with the chemicals it encounters. However, it is also hydrophobic, meaning that it does not bond with water. At a recent pilot demonstration in Ohio, Obsorb was used in the form of a white powder to suck up a plume of TCE (a volatile organic compound). TCE is particularly difficult and expensive to clean up using conventional means, which is the reason why some contaminated sites are simply shut down, allowing the vapors to dissipate naturally. The process takes decades, so Obsorb could provide a low-cost means of recovering sites more quickly. The venture development group JumpStart Inc. saw the potential and has just committed a $250,000 investment to Absorbent Materials.
Once full, Obsorb floats to the surface, where it can be skimmed off with something as simple as a coffee filter. After that the pollutants can be retrieved and the glass can be reused hundreds of time. Nanoparticles of iron can also be added to convert TCE or PCE (another volatile organic compound) into harmless substances. As a low cost form of cleanup, swelling glass could provide site remediators with yet another in the growing list of non-conventional cleanup tools along with lactate, vitamin B-12, and even cattails.
From ““Swelling Glass” Cleans Polluted Water Like a Sponge“, by Tina Casey
From Industrial Hub To Sustainable Neighbourhood
Posted in Models by Kate Archdeacon on December 18th, 2009
Source: Daily Commercial News
From “Vancouver industrial hub transformed into sustainable neighbourhood” by Jean Sorensen
Southeast False Creek (SEFC), a City of Vancouver reclamation project, is being designed to set a new urban sustainability standard in community development. The 80-acre site housing 16,000 people will become a neighbourhood of parks, market and subsidised housing, marine areas, community garden, shops, schools, and a community centre, growing out of what was once the industrial hub of the city. Sawmills, manufacturers, metal shops and marine-related shops once rimmed False Creek. Subsurface investigation was made into soil and groundwater quality at SEFC to complete human health and risk assessment as part of a remedial action plan. In areas where contamination was severe, soils were removed and in areas of lesser contamination, the material was covered over and the land designated recreational use.
“I am told that this is the largest residential development in North America,” said Robin Petri, Vancouver’s Manager of Engineering for the SEFC & Olympic Village. One of the unique features of the development, Petri points out, is that the roads are sloped so that rainwater drains into natural bioswales on each side of the village, negating the need to treat runoff water, while providing habitat for birds, animals, and marine life. Buildings also capture and use water, with approximately 50 per cent having green roofs and 50 per cent directing the water into irrigation and functions such as toilet flushing. A neighborhood energy utility is the first in North America to gather heat directly from a raw sewage line, consolidate the heat and use it in a thermal system that loops pipe to various buildings and back to the utility building.
One of the challenges of the cleanup was that False Creek had been filled in along the shoreline over the years. Much of the earlier materials used for fill were poor quality and these had to be removed and replaced. To compensate for shoreline that was removed, an island was created in an inter-tidal zone allowing children to wade to it at low tide to examine marine life that has been returning to a once-derelict area. In February a project manager noticed white frothy bubbles around the island. It turned out to be herring roe – the first time it has been seen there in 50 years.
Read the full article by Jean Sorensen.