Industry Market Trends
Industrial Processes Call for Customized Approaches to Wastewater
July 22, 2013
Monadnock Paper Mills in Bennington, N.H., told me in an interview that "for municipal plants, their largest issue is parasites, things like E. coli. But in industrial treatment systems, each waste stream is different, depending on the actual chemicals used in the facility." For example, Monadnock's operations produce large volumes of short paper fiber, so the plant's sludge-handling process is crucial. Monadnock recovers and treats its sludge in such a way that it can be used by local agriculture for topsoil. The basic kinds of wastewater treatment processes are physical, biological, and chemical. Physical processes remove solids by such means as screening, skimming and settling. In biological processes, bacteria and other organisms are used to consume organic matter. Chemical processes can be used to act on pollutants in ways that allow them to be more easily removed from wastewater. A primer from the U.S. Environmental Protection Agency (EPA) explains the three conventional steps in wastewater treatment:Water is a mission-critical resource for industrial firms, and wastewater treatment makes up an important component of many company's water-management strategy. Increasing water scarcity and stress, along with ever-stricter government regulation, compel industrial firms to seek out ever-more-efficient systems for treating their wastewater. How do manufacturing and industrial firms treat their wastewater? Although we're discussing industrial wastewater treatment here, the best place to start is describing conventional treatment processes. Nearly any industrial plant will need to process sewage -- graywater and human waste -- either through an in-house plant or by feeding it to a municipal facility. For any enterprise large enough to need its own wastewater facilities, the default system would be more or less based on the three stages of primary, secondary, and tertiary treatment. However, a manufacturing or industrial plant will require that standard model to be altered or augmented, depending on the types of processes carried out at the facility. Michelle Hamm, environmental manager at
- Primary treatment removes coarse solids from wastewater after preliminary screening for large floating objects. In a sedimentation tank, suspended solids settle to the bottom, forming primary sludge, which is usually removed using mechanical equipment.
- In secondary treatment, organic matter is removed using biological processes. According to EPA, the two most common methods for secondary treatment are attached growth processes, in which microbial growth occurs on the surface of a plastic or stone medium; and suspended growth processes, in which microbial growth takes place suspended in the water, which is aerated or agitated to introduce oxygen.
- Tertiary treatment (a.k.a., advanced treatment) refers to any treatment processes employed after secondary treatment before discharge into the environment. Tertiary treatment can involve filtration, disinfection, odor control, and removal of elements such as nitrogen and phosphorus.