Industrial Wastewater Treatment Acidification

Industrial wastewater treatment can be a difficult process due to the many factors involved. It can vary in strength, composition and contaminants resulting in a very diverse range of solutions that need to be applied.

This can make it hard to find the optimum solution for a particular case. It’s important to consider the type of wastewater being generated, what the purpose is for it and the environmental regulations that are in place.

Acidity

Industrial wastewater is a waste product or byproduct generated by many industries. It may be discharged, based on local regulations and permit requirements, or recycled within the industrial process.

Whether discharged or recycled, it must be treated to an acceptable level. Treatment processes are usually designed to remove contaminants such as dissolved organics, metals and acids.

Acidity is a property of solutions that determines their ability to form reactions with various bases and to produce salts. Acidic solutions generally have a pH below 7.0, and are often called corrosives.

The pH scale runs from 0 (very strong acid) to 14 (very strong alkali). A solution is said to be neutral, if its pH is around 7. It can be controlled by adding a base to adjust the pH.

Alkalinity

A critical ingredient for the smooth running of an industrial wastewater treatment plant is alkalinity. Biological processes, such as nitrification and anaerobic digestion, rely on water’s alkalinity for their optimal pH conditions.

Water’s alkalinity is largely determined by the local geology and other factors, such as chemical additives and cleaning agents that are added to water. For example, a household detergent might contain bicarbonates and carbonates that are washed into surface waters from drains and may also affect the alkalinity of sewage.

As a result, it’s important to maintain wastewater alkalinity levels during the acidification process. Lime slurries are the most commonly used solution for maintaining alkalinity, because they minimize potential scaling in the wastewater distribution system and are inexpensive.

Neutralization

The industrial wastewater treatment process of neutralizing the acidification of a waste stream is an important step in many industries before it can be discharged to sewer systems, lakes and streams. Acidic wastewaters are prone to contain high levels of metals and chemicals that can be harmful for water quality and biological processes.

The acid-base neutralization reaction is a type of replacement chemical reaction where the hydrogen ions (H+) in an acid are canceled out by the hydroxyl ions (OH-) of a base. This reaction is exothermic and produces water and a salt.

Neutralizing chemicals range from simple items like citric acid or sodium bicarbonate (baking soda) to complex combinations of solidifiers and neutralizers. Selecting the best chemicals to use for a particular application requires considerations such as safety, cost and convenience.

Disinfection

Industrial wastewater treatment systems typically handle a variety of different wastes, including liquid and solid wastes generated by various industrial processes. These processes vary by industry and by environmental, regulatory, and economic considerations.

A key goal of industrial wastewater treatment is to reduce the amount of solids in the discharged water. This is often done through simple sedimentation techniques.

However, very fine solids or sand may need to be removed using more complicated methods, such as ultrafiltration or flocculation with alum salts or polyelectrolytes.

Disinfection is the process of eliminating microorganisms and bacterial spores from inanimate objects or surfaces. It is a necessary step to prevent cross-contamination between objects and the environment.