Water is an essential part of many industrial processes. It is used for fabricating, processing, washing, cooling and transporting products or equipment.
The type of industry and specific activities and operations determine how much and what kind of wastewater is generated. This can make it difficult to choose a treatment process that will be most effective.
Oil and Grease
Fats, oils and grease (FOG) can have serious impacts on wastewater systems. They clog drain lines, interfere with wastewater treatment and can cause sewer overflows.
Problems with FOG in industrial wastewater systems are common. They can affect sanitary sewers, lift stations and sewage pumps.
When FOG enters the wastewater system, it mixes with food and other sanitary waste, congeals and hardens within the pipes. It can also cause unpleasant odours.
The best way to prevent FOG problems in the wastewater system is to keep it from entering. It can be done by reducing the volume of FOG discharged and by controlling the type of fats, oils and grease that are used or produced at an industrial facility.
Grease can be removed from wastewater using skimming in a skim tank or gravity separation in an API separator. The heavier oils and grease settle to the bottom of the wastewater, while lighter oils remain on top.
Industrial wastewater contains a broad range of contaminants, including chemical residues and microplastics. These can vary in quantity and concentration depending on the source of pollution.
A number of chemical treatment processes can aid in the removal of chemicals from wastewater, thereby making it less harmful. These include pH adjustment, odor control and disinfection.
In some cases, wastewater may contain hard water (water with a high mineral content). These waste streams often need to be treated to remove the minerals before they can be re-used for further industrial processes.
In these instances, a number of chemical processes can be used to soften the water, lower the concentration of heavy metals and other dissolved substances. These can be achieved through ion exchange, or precipitation.
Dissolved solids problems are often the result of industrial wastewater systems that generate a large quantity of oil, grease, and other organic contaminants. Many of these problems can be addressed through sedimentation techniques and the recovery of the solids for reuse.
The total amount of minerals, metals, cations, anions, and salts dissolved in water is called “total dissolved solids” or TDS. It is measured in mg/L or milligrams per liter of water.
A high TDS level may indicate that there is a large concentration of toxic trace metals such as nitrate, arsenic, copper, aluminum, and lead present in the system at elevated levels.
High concentrations of dissolved solids are more likely to be a problem in groundwater than surface water because of the longer time groundwater spends in the rocks and sediments that make up aquifers, weathering those materials. However, a large percentage of dissolved solids in groundwater come from detergents, fertilizers, road salt, urban runoff, animal and human waste, and other sources of pollutants.
Biochemical Oxygen Demand
Biological oxygen demand is an important parameter for assessing wastewater treatment. It indicates the amount of oxygen that bacteria and other microorganisms consume while decomposing organic waste.
In a wastewater treatment plant, BOD is often measured at various points in the system from influent to effluent. It can also be used to model the treatment process and determine its efficiency.
High concentrations of BOD can be found in many industrial processes, such as brewing, dairy, and food processing plants. These industries produce high volumes of waste, which can be difficult for beneficial bacteria to break down.
When wastewater is released into a stream or lake, higher BOD concentrations can result in the depletion of dissolved oxygen (DO) levels. This can cause aquatic organisms to suffocate or die. This is because dissolved oxygen is essential for life in water.