Industrial Waste Treatment: Methods and Best Practices
Treatment is done to reduce the volume or the toxicity of a solid or liquid waste stream prior to disposal. It can also create additional opportunities for the reuse or recycling of treated materials.
Waste treatment can oftentimes be preceded by a pre-treatment phase, as is the case with construction/demolition waste or hazardous waste. This phase can include separation and sorting, fragmentation, compressing, drying, and more, depending on the stream type. The treatment phase is usually split into three main categories: mechanical, chemical, and biological. Mechanical treatment relates to changing the waste’s physical properties, whereas the chemical and biological categories address a stream’s chemical composition. For mixed waste (e.g. solid and liquid, organic and inorganic, hazardous and non-hazardous), a combination of these methods might be needed.
Common mechanical treatment methods encompass particle agglomeration, immobilization, filtration, and solidification, among many others. They focus on changing the size, shape, density, or state (e.g. solid to liquid) of the stream. Chemical treatments consist of adding reagents to waste to create specific chemical reactions that separate valuable materials. Examples of such methods are neutralization, oxidation, Ion exchange, and more. Biological treatments involve both aerobic (oxygen-driven) and anaerobic (microorganisms-driven) procedures.
Liquid waste (e.g. wastewater and sludges), on the other hand, requires more careful consideration given its mixed composition and high level of hazardous materials (e.g. toxic, flammable, radioactive, etc.). As such, additional steps are needed, beginning with the removal of various pollutants, such as salts, solids, oils, organics, and acids. The subsequent treatment will often involve more than one of the methods above.
Most wastewater is municipal or home-based (e.g. sewage water); few forms are commercial or industrial. Among the wastewater-producing industries, oil & gas and petrochemicals are two major ones. Oily residue, solids, as well as hazardous materials are common byproducts of these sectors that get released in water effluents and require special consideration. At Estedama, we employ tailored methods for treating various industrial waste streams, including contaminated sand, drill cuttings, oily sludge, oily water, chemical water, acidic water, flowback and produced water. We can efficiently treat large volumes of waste while separating and recovering valuable materials, such as crude oil, treated water, and solids.
One challenge with treating wastewater is its collection; oftentimes, treatment needs to be done on-site. Given such complexity, this type of waste is treated in specially designed wastewater treatment plants (WWTP), which can be fixed or mobile. These vary in size, effectiveness, and goals. The effectiveness of a WWTP is based on its technologies/equipment, maintenance, and location. Estedama offers a mobile sludge recycling plant, especially designed for our heavy industry clients, that assists them with making environmentally responsible choices while also minimizing transportation costs. We’re also able to consult with our clients on the best approach to engineer and design their own treatment processes and plants.
Several factors should be considered when building a WWTP for optimal efficiency, including infrastructure, geology, slope, elevation, soil, wind direction, groundwater and above-water bodies, rural and urban settlements, and land use. Further, if generating energy from the waste is an important goal, then the plant should also be close to both the source of the waste and the potential energy customers.
While mostly a disposal method, incineration is sometimes considered a type of treatment (aka thermal treatment) for solid or mixed waste. Few variations of the incineration process fall under that umbrella too, including pyrolysis, gasification, and more. Thermal treatment plants have the advantage of harnessing the resulting heat or electricity for reuse.
More and more treatment plants are adopting innovative techniques of converting waste into energy. For example, plasma-assisted gasification (PAG) combines two novel technologies - plasma treatment and gasification. This integrated approach proves highly effective in transforming carbon-containing waste into a clean gas, used for electricity generation in gas engines, dual-fuel generators, gas turbines, or fuel cells.
Overall, waste treatment is a complex journey meant to reduce the amount of pollution released into the environment. It is a critical step in industrial waste management that not only changes the waste itself but also our understanding of responsible resource management. As Estedama’s Senior Process Engineer describes it, "addressing the intricacies of waste treatment demands not only a blend of physical, chemical, and biological methods, but also continuous research and development for further innovation, culminating in the most effective environmental restoration."