Industrial Wastewater Treatment 101 – How Is Industrial Wastewater Handled?
Industrial companies that produce wastewater as part of their business process need to meet discharge regulations and follow safety precautions. The process of properly treating their wastewater avoids any harm to the facility’s products or process, human health, and the environment. It also helps avoid fines and possible legal action if wastewater is improperly discharged into a publicly owned treatment works or into the environment.
Meaning of wastewater treatment system
A wastewater treatment system typically comprises several individual technologies that address specific wastewater treatment requirements.
A well-designed and efficient wastewater treatment system must be able to handle:
- Possible changes in water effluent requirements
- Variations in water chemistry needs and required chemical volume adjustments
- Process variations in flow and contamination
What’s included in a basic wastewater treatment system?
The exact components of the wastewater treatment system depend on the characteristics of the wastewater itself, and specific regulatory requirements for discharging from the plant. But in general, a basic wastewater treatment system includes the following:
- Filtration to remove leftover trace amounts of suspended solids
- Chemical feed to facilitate the coagulation, flocculation, or precipitation of any suspended solids and metals
- Clarifier to settle suspended solids that are present as a result of treatment
- Final pH adjustment and any post-treatment
- Control panel (depends on the level of automated operation needed)
These are considered standard components. However, if a treatment plant requires a system that provides more customization, there might be a few added technologies or features. For example, for facilities that generate biological demand like beverage and food, a biological treatment system will help to reduce the biochemical oxygen demand (BOD).
What Wastewater treatment system removes?
An industrial wastewater treatment system has technological components to remove any of the following:
Biochemical oxygen demand (BOD)
BOD refers to the needed amount of oxygen dissolved by aerobic biological organisms to break down the organic matter into smaller molecules. High levels of BOD indicate an elevated concentration of biodegradable material present in the wastewater and can happen from the introduction of pollutants like cleaning, fecal waste, wash-down from fertilizer runoff, or food processing.
Phosphates and nitrates
If a large number of phosphates or nitrates are not removed from the wastewater and these nutrients are discharged in the local environments, it can lead to an increase in BOD and extensive growth in phytoplankton, algae, and weeds.
Pathogens are fungi, viruses, bacteria, or any other microorganisms that can be present in the wastewater that can lead to all types of health issues including severe digestive problems, acute sickness, or death.
Metals found in industrial wastewater are the result of various manufacturing process. Metals can lead to extensive damage to human health and the environment. They are specifically damaging because they do not break down and tend to accumulate leading to toxic environs.
Total suspended solids
Total suspended solids (TSS) in wastewater, inorganic and organic solid material suspended in the water, like many of the other contaminants listed, harm aquatic life. They can also be problematic if the wastewater is reused for the process, depending on whether you need to discharge the wastewater in a publicly owned treatment works or environment or reuse the wastewater for additional processes. TSS can decrease the oxygen levels in aquatic environments and kill insects.
Total dissolved solids
Total dissolved solids (TDS) are minerals, metals, cations, anions, or salts found in wastewater. They can cause issues with aquatic life, crops, and irrigation. They can also seep into the groundwater. TDS can be generated in wastewater from any industry.
When pesticides or other chemicals are used during the manufacturing process, they can be transmitted to the environment and humans through wastewater, leading to damage. A few common chemicals found in wastewater include DDT, PCBs, dioxin, diethylstilbestrol, and other pesticides.
Working on the wastewater treatment system
A typical wastewater treatment facility process usually includes the following steps:
Coagulation is one of the processes where many chemicals are added to the reaction tank for the removal of bulk suspended solids and other various contaminants. The process starts off with an assortment of mixing reactors, typically one or two reactors that add specific chemicals to take out the finer particles in water by combining them into heavier particles that settle out.
When coagulation is complete, the water enters a flocculation chamber where the coagulated particles stir together with long-chain polymers, creating visible, settleable particles resembling snowflakes.
The gravity settler is typically one large circular device where flocculated material and water flows into the chamber and circulate around typically from the center out. In a very slow settling process, the water rises to the top and overflows at a perimeter of the clarifier. It allows the solids to settle down to the bottom of the clarifier into a sludge blanket.
The next step is usually running the water overflow into the gravity sand filters. The filters are large areas of sand (about two to four feet across). The sand is finely crushed silica sand with jagged edges. The sand is typically installed in the filter at the depth of two to four feet that is packed tightly. The feedwater is then passed through the sand, which traps the particles.
After the water flows through the gravity sand filter, the next step is typically chlorination or disinfection to kill the bacteria in the water.
If the wastewater is reused in the industrial process, it is pumped into a holding tank where it can be used based on the facility’s demands. When we talk about municipal use, the treated water is pumped into a distribution system of water towers and various distribution and collection devices in a loop throughout the city.
CWE’s role in Industrial Wastewater Treatment
CWE treats diverse streams of wastewater that come to us from manufacturing facilities, landfills, refineries, and chemical plants. A few examples of wastewater services we offer are:
- Waters that contain resins, fuels, oils, glycols, alcohols, and other organics
- Heavy metals laden waters
- Acids and caustics
- Flammable waters and combustible
- Process waters and machine coolants
CWE offers high-end wastewater treatment that includes neutralization, filtration, extraction, separation, and recycling of wastewater streams. Our facilities for hazardous and non-hazardous wastewater management deliver environment-friendly wastewater streams. CWE also uses tried-and-tested processes and innovative systems to generate effluent that meets regulatory compliance.
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