Alkalinity is a measure of the acid-neutralizing capacity of water and is measured by titrating the solution with an acid (ex. H2SO4) until it reaches a known endpoint wherein its pH changes abruptly. Alkalinity of wastewater is measured as it affects biological processes and chemical reactions.
Acidity
Acidity is a measure of a solution’s capacity to react with a strong base (ex. NaOH) to a predetermined pH value. Acidity levels are measured in wastewater because it can be responsible for corrosive properties and can take a leading role in regulating biological processes as well as in chemical reactions.
Heterotrophic Plate Count
Heterotrophs are a group of microorganisms that use organic carbon sources to grow and can be found in all types of water. Heterotrophic plate count (HPC) is a method that measures colony formation on culture media of heterotrophic bacteria in drinking water. Thus, the HPC test can be used to measure the overall bacteriological quality of drinking water systems. High levels of microbial growth can affect the taste and odor of drinking water. To determine HPC, pour plate method can be used as a method.
Total Coliform & Fecal Coliform
Total coliform bacteria are commonly found in the environment and are generally harmless while fecal coliform bacteria are a sub-group of total coliform bacteria. The presence of fecal coliform in a drinking water sample often indicates recent fecal contamination, meaning that there is a greater risk that pathogens are present than if only total coliform bacteria is detected. The presence of fecal contamination in aquatic environments is an indicator that a potential health risk exists for individuals exposed to this water. Multiple tube fermentation technique is often used for the determination of total and fecal coliforms.
Oil and Grease
Oil and grease is defined as any material recovered as a substance soluble in extracting solvent. It can be composed of fatty matter from animal and vegetable sources and from hydrocarbons of petroleum origin. Oil and grease in water can cause surface films and shoreline deposits leading to environmental degradation, and can induce human health risks when discharged in surface or ground waters. Presence of excessive amounts may interfere with aerobic and anaerobic biological processes and lead to decreased wastewater treatment efficiency. Liquid-liquid partition by solvent extraction is the most widely used method for the determination of oil and grease.
Total Suspended Solids (TSS)
Total suspended solids (TSS) are particles that are larger than 2 microns found in the water column. Most suspended solids are made up of inorganic materials, although bacteria and algae can also contribute to the total solids concentration. TSS is also a significant factor in observing the aesthetics of the water, as the more suspended solids that are present the less clear the water will become. Excessive suspended solids can because for concern for aquatic and human life as well as impede navigation and increase flooding risks. TSS can be measured through gravimetric determination.