Ground Water Treatment

The ground water contamination is nearly always the result of human activity. In areas where population density is high and human use of the land is intensive, ground water is especially vulnerable. Virtually any activity whereby chemicals or waste may be released into the environment, either intentionally or accidentally, has the potential to pollute ground water.

The consequences of contaminated ground water or degraded surface water are often serious to environment and human health:

• Estuaries impacted by high nitrogen from ground water sources have lost critical shellfish habitats;
• Water supply, in some instances, ground water contamination is so severe that the water supply must be abandoned as a source of drinking water;
• Plants and agriculture cultures, animals can be damaged and poisoned.

The ground water may be contaminated by various sources:

• Natural substance as: decay of the organic matter, compounds found naturally in rocks or soils, such as iron, manganese, arsenic, chlorides, fluorides, sulphates, or radionuclides, etc.;
• Septic systems as: effluents from septic tanks, cesspools, and privies, that can contain bacteria, viruses, nitrates, detergents, oils, and chemicals;
• Improper disposal of hazardous waste;
• Releases and spills from stored chemicals and petroleum products (especially for abandoned industrial area);
• Landfills;
• Surface impoundments;
• Pesticide and fertilizer use;
• Sewers and other pipelines;
• Mining activities;
• Injection wells/floor drains.

In some cases, the contaminants can be naturally diluted or removed, but specific treatments shall be selected.

Here below is described a process flow treatment, among others, that PSC S.p.A. Engineering & Contracting (PSC) can design, to remove industrial organic pollutants as chloride solvents:

• Air stripping as primary treatment to strip volatile organic compounds to reduce the large concentration from the contaminated water. In some case the off-gas shall be re-treated to respect the environmental emission limit;
• Advance oxidation process (UV + hydrogen peroxide or ozone) as secondary treatment to remove low contents by chemical oxidation;
• Activated carbon filters as final polishing solution to adsorb the residual pollutants from main stream water;
• Gas transfer membrane and bio filtration process could be used as alternative to air stripping (in most case a pre-treatment could be required to protect the system).

The above process treatment could require additional steps, according to the inlet contaminated ground water characteristics. PSC is available to analyse the ground water characteristics, and evaluate different scenarios for Client’s comparisons, depending on their goals.

The treated water could be discharged into the initial aquifer, well, surface water or reused for industrial uses as irrigation, washing, cleaning purposes.