Underground Water Treatment
The quality of water for human consumption is related to the characteristics and purity of surface and groundwater resources to be achieved by appropriate aquifer protection measures. The same purpose can be achieved by applying appropriate water treatment measures prior to delivery to achieve a reduction in the hazards of undesirable elements and ensure the water’s suitability for consumption during distribution. The choice of a treatment system is related to a multitude of factors such as effectiveness in risk abatement depending on the type of water treated, the ability to keep multiple risks and investment costs under control, the availability of adequate space for the system, the management of reagents and waste products from the process, and the availability of properly trained personnel.
What do groundwater treatments deal with?
Groundwater treatments remove chemical pollutants such as iron, manganese, arsenic fluoride, vanadium, boron, or uranium, or even anthropogenic compounds such as trietetrachloroethylene, ammonia, nitrates, pesticides, and chromium. Advanced treatments are required for industrial compounds. Conventional treatments include sand filtrations, coagulation, sedimentation and/or clariflocculation, filtration and disinfection. Activated carbon treatment is used for water contaminated with organic micropollutants such as pesticides or organohalogenated solvents.
Classification of Underground Water Purification Treatments.
There are a large number of groundwater treatment processes, the applicability of which is to be related to the characteristics of the water to be treated and the degree of purification required. Purification treatments are classified according to two methodologies.
1) Classification According to the Succession of Treatments.
According to this classification, distinctions are made:
- Pretreatment: coarse and fine screening, desanding, de-oiling, equalization and homogenization, neutralization.
- Primary treatments: flotation, sedimentation, chemical precipitation.
- Secondary treatments: activated sludge oxidation, on percolating filters, on biodiscs, in aerated or non-aerated lagoons, anaerobic digestion, biological sludge sedimentation, disinfection.
- Tertiary treatments: nitrification-denitrification, phosphorus precipitation, clariflocculation, filtration, adsorption on activated carbon, ion exchange.
Primary treatments remove and greatly reduce suspended and floating materials, while they are ineffective on colloidal materials and dissolved substances. Secondary ones remove or greatly reduce colloidal materials and suspended and dissolved organic substances. Finally, tertiary treatments, also known as advanced treatments, remove or reduce nutrients, organics, suspended solids and dissolved salts to much more stringent levels than can be achieved by secondary treatment.
2) Classification According to the Nature of Processes.
According to this classification, distinctions are made:
- Mechanical treatments: screening, desanding, de-oiling, equalization and homogenization, flotation, sedimentation, filtration.
- Biological treatments: activated sludge oxidation, on percolating filters, on biodiscs, in aerated or non-aerated lagoons, anaerobic digestion, nitrification-denitrification.
- Chemical-physical treatments: neutralization, coagulation-flocculation, chemical precipitation of metals and phosphorus, stripping of ammonia and sulfides, disinfection, adsorption on activated carbon, ion exchange.
Mud Treatment
Most water treatment processes give rise to the production of sludge; in biological processes these result from the transformation of organic matter into microbial cell mass, in chemical-physical processes from the separation of suspended materials, the precipitation of dissolved substances and the addition of chemicals. Sludge must be treated in such a way that it can be disposed of without harming the environment. Sludge is treated to reduce its water content and make it disposable without environmental damage.
