One of my readers highlighted the case of the recent coal ash pollution from power plants in North Carolina U.S. This is the typical problem that can be fixed using sustainable solutions.
Coal ash is a by-product from the production of electricity obtained burning coal in power plants. Coal is a non renewable material, that is, it can regenerate in geological eras rather than through relatively fast biogeochemical cycles. It can be a pollutant because of the polluting substances contained in it, such as heavy metals, alkali sulfates and organic materials. Moreover, this kind of waste has a high acid-formation potential, coming from the oxidation of sulfides, and an acid environment results in the mobilization of toxic metals and acid drainage, which can negatively affect receiving water bodies. Air pollution, with the dispersion of micro and nano particles, can be a further relevant concern.
From a sustainable and technical point of view, the issue can be managed through either short, medium and long term plans with:
- Prevention and
Short term, from a few months to one year:
- Remediation of the already contaminated sites with the appropriate techniques according to the specific pollution and the particular polluted environment (water, groundwater, soil and air);
- Prevention with the decrease in the production of potentially hazardous waste, for instance with an appropriate treatment of the coal ash prior to the final disposal;
- Prevention with the use of appropriate containment technologies at the landfills and ponds where the coal ash is disposed off;
- Prevention with the removal of the coal ash from landfills and ponds that do not ensure present and long-term environmental protection;
- Prevention increasing the use of recycling methods. A solution for the management of this kind of potentially hazardous waste could be the cement kilns. Materials used to produce cement already virtually contain traces of every natural element, including heavy metals and organic substances, and most of them can be oxidized and stabilized in cement kilns, requiring no further treatment.
Medium term, from one year to three years, solution:
- Building photovoltaic plants for the production of electricity on the polluted lands after the remediation, if they are not reusable for other purposes, and
- Building photovoltaic plants on the appropriately sealed landfills and ponds, after their closure, where the coal ash has been already disposed off.
This part of the solution could be beneficial also in order to save other land, which is still potentially usable for agricultural purposes, and then for food purposes, rather than for the production of energy.
Long term, after three years and beyond, solution:
- Replacing power plants burning coal with photovoltaic plants.
The gradual replacement of coal-fired power plants with photovoltaic plants could provide benefits such as:
- The use of solar energy instead of fossil fuel avoids the deterioration of natural resources and the pollution produced with coal mining;
- Reducing combustions means reducing the pollution of air, water and soil and the negative impacts on the greenhouse effect and on climate change, which causes more and more frequent and intense disasters (floods, landslides, desertification and the like);
- Idle areas, like polluted sites, can be turned into economic sustainable resources and into opportunities that benefit the environment, the region and its economy.
Every action should be coordinated with the local communities balancing environmental, social and economic issues on a local, regional and global scale.
Sustainability looks at the long term and is comprehensive.
Paola Morgese, PMP
Civil Hydraulic Engineer
M.S. Sanitary and Environmental Engineering
Published as a LinkedIn blog post in August 2014