What do you mean by water pollution?
Pollution is a harmful situation that poses a threat to local environments. For water, pollution is when the properties of water change. The change can be in the biological content the chemical composition or the physical properties. Chemicals and microorganisms are typical types of water pollutants. For example, when a substance contaminates a concentration of water we consider it chemical pollution. The effect of the pollutant can be harmful always or only above a certain concentration.
The water on the planet diverges into two main classes, salty water, and freshwater. For different environments, there are different pollution concerns. While salty water accounts for most of the water on the planet. This article will only look at the scope of freshwater pollution.
Freshwater is almost anywhere on land, from soil glaciers, vegetation, and water bodies. When thinking about pollution concerns you should consider sites with a concentration of water and for that, we examine rivers, lakes, and groundwater (aquifers). Similar categories of pollutants reach all those mediums, but the potential hazard they cause on each one is different.
Categories of water pollutants
Biologic
- Infectious Agents – are organisms that can cause infection or lead to infectious diseases. In this category, you may know Bacteria Viruses, and practices.
- In the case of drinking water, any form of life like worms or tadpoles is a pollutant.
Chemicals
- Acidic compounds – are substances that change the ph level of the environment. This change affects the biological and chemical processes in the water. Acidic compounds will also ionize in water and may create the condition for the creation of other toxic chemicals.
- Metals and heavy metals often get discharged into the environment with industrial waste. Heavy metals may concentrate in the fat tissues of animals and create a dangerous process in which containment moves up across the food chain. This process is called biomagnification and can lead to dangerous concentrations higher up the food chain. An example of that is the mercury found in tuna fish.
- Radioactive Materials from industrial or medical waste. In this group, we have radon, cesium, uranium, and iodine. They may be very toxic to marine life.
- Plant Nutrients or the composted results of organic waste and the biological pollution after degradation. Phosphates Nitrates are salts that ionize in water and enable chemical symbiosis between elements in the environment. They are crucial for the ecosystem to function and will be naturally produced by microorganisms in the soil. Concentrating too high on those leads to negative effects because it exceeds the natural balance in the environment.
- Organic compounds like crude oil derivatives (Oil, Gasoline, Plastics, etc’) or pesticides used in cultivated lands. The first is mainly discharged by accident for example on transportation. Pesticides can become a pollutant during runoff events.
Suspended solids
Floating solid parts can get to the water from many sources. Common sources are leftovers from organic degradation and runoff soil and slit. Depending on whether the water is for domestic use or discharge and the content of solids the standards vary. One example of the negative effect of suspended solid is clear if you think about machineries like pumps that are sensitive to the change in water quality and properties.
Thermal and noise pollution
An additional by-product of human activity is energy pollution. The main forms of energy are kinetic and thermal. The first mainly concerns the noise that interrupts the natural habitat. The motion effect of floating energy projects should also be examined since it can cause kinetic interferences. For thermal energy water pollution, you can consider the dissipation of hot water from industrial uses.
American water standards
The American agency for environmental protection was early to acknowledge the problem and announced the clean water act back in 1972. The act defines the 33 Hazardous pollutants to track on discharge water to avoid pollutants from being released into the environment.
The European water standards
degrading water quality is a threat both to local and regional communities. Which led the European Parliament to establish tracking and limits on some of the pollutants. In a decision that follows the American clean water act the European parliament, defined the maximal concentration for 33 priority substances. We know those substances threaten the aquatic environment when transferred through them. There are additional 8 substances that are specifically relevant for lakes and still water deposits. The list is stated in ANNEX 1 of this European law.
Water treatment
To ensure sufficient water quality, avoiding the previously discussed pollutants and the harm they may cause to the environment there is regulation. The last obligates the treatment of wastewater. The type of treatment varies depending on where will they be discharged or reused. Two main types of treatments are wastewater and drinking water treatment.
Wastewater treatment plants (WWTP)
Before discharging the water from the industrial or domestic waste we clean them in a wastewater treatment plant. In such a plant we run the water through a few processes to ensure water quality that meets standards for every type of pollution. We handle suspended solid particles the WWTP uses settling tanks. For chemicals, the water will go through an aerobic organic degradation tank as well as an un-aerobic one as well as the addition of chemicals that will react with the chemicals to create a less hazardous substance. To end with we will purify the water, typically using chlorine, to make sure biologic pollution is not dismissed into the environment.
What makes water safe to drink?
The standards for safe drinking water vary based on geographic area and the means of the local authorities. In developed countries, the standard is better than the one in developing countries.
In general, we set the bar for drinking water higher than the one for wastewater discharge. Some industrial facilities may need a more pure composition of water which we can achieve by extra treatment for the incoming water.
