Water Quality

Water Quality is an event for 2011-2012. Important components of the event include identifying aquatic invertebrates and understanding the indicators of water quality.

The Basics
What is water quality? Water quality includes the physical, chemical and biological characteristics of water. In countries around the world, especially in the U.S. under the direction of the EPA, standards are set to determine whether water is potable, or safe to drink.

Salinity
Let's first discuss salinity, a property of water describing its salt concentration. Salinity is measured by dissolved salts in parts per thousand (ppt). Fresh water has a ppt of <0.5, which means that there are 0.5 molecules of dissolved salt for every 1000 molecules of solution, or 1 molecule of salt per every 2000 molecules of solution. Brackish water has a ppt between 0.5 and 30, saline water has a ppt between 30 to 50, and brine has a ppt of >50. The only water safe for human consumption is fresh water.

The Water Cycle
Also known as the hydrologic cycle, the water cycle describes the movement of water throughout the Earth. To recap on the basics, water enters the atmosphere through evaporation and transpiration (sometimes referred to together as evapotranspiration), condenses to form clouds, and within a week of entering the atmosphere precipitates to replenish the Earth's surface water and form runoff. From then on, water has two options: either evaporate again, or infiltrate the surface to become groundwater, where it can be sucked up by plants or replenish aquifers. Though water that penetrates the ground usually stays there for long periods of time, eventually the cycle will come in full circle for all the water on Earth.



Wastewater Treatment
Treatment in the US costs $12 billion a year, and is expected to double in 10 years.

Septic-Tank Disposal Systems: This is the conventional method for treatment. A sewer line from the house leads to an underground septic tank in the yard. This tank is designed to separate solids from liquid, digest and store organic matter, and allow the treated sewage to seep into the surrounding soil. As the wastewater moves through the soil, it is further treated by the natural processes of oxidation and filtering.

This method can fail if the tank isn't pumped out when it's full of solids or if there is poor drainage in the surrounding soil.



Wastewater Treatment Plants: Raw sewage is delivered to the plant through a network of sewer pipes. Following treatment, the wastewater is discharged into rivers, lakes, or the ocean.



Wastewater treatment is divided into three categories: primary, secondary, and advanced. Primary and secondary treatment is required by law for all municipal plants in the US. When secondary treatment isn't enough to clean water, advanced treatment is used.

Competing
You may bring in one two-sided page of resource notes and 2 non-programmable/graphing calculators. Z87 splash goggles are required.

The test will cover areas such as aquatic ecology, the water cycle, nutrient cycling, aquatic chemistry, potable water treatment, waste water treatment, aquatic food chains and webs, community interactions, population dynamics, watershed resource management issues, sedimentation pollution, and harmful species.

Aquatic Ecology: