Digital Feature: Achieve Water Authority Compliance with Automated Wastewater Treatment for Industrial Facilities with Cooling Towers
Author: S. BOUTUREIRA, Sabo Industrial Corp., Newburgh, New York
U.S. industrial facilities with cooling towers must meet U.S. Environmental Protection Agency (EPA) and local wastewater requirements for effluent, including those under the Clean Water Act. Failing to do so can result in severe fines that quickly escalate.
A wide range of industries utilize cooling towers in their facilities, such as metal processors and rubber, chemical and plastic product manufacturers. Industrial facilities with a cooling tower require a water treatment system to ensure an efficient process and long equipment life. If cooling tower water is not treated properly, fouling, scaling, corrosion and organic growth can trigger sizeable EPA and local environmental agency fines. In addition, this can cause facility downtime, reduce productivity and necessitate costly, premature equipment replacement.
A cooling tower water treatment system consists of various technologies needed to regulate the level of alkalinity, chlorides, hardness, iron, organic matter, silica, sulfates, total dissolved solids (TDS) and total suspended solids (TSS). Although the type of industry and specific operational practices determine the type of wastewater generated, most involve suspended solids, heavy metals, organic compounds or a variety of other pollutants. Under the Clean Water Act, for example, the EPA has identified 65 pollutants and classes of pollutants as “toxic pollutants,” of which 126 specific substances have been designated “priority” toxic pollutants.
For many plants utilizing cooling towers, this means installing a wastewater treatment system (FIG. 1) that effectively separates the contaminants from the water so it can be legally discharged into sewer systems or even reused.
However, traditional wastewater treatment systems can be complex, often requiring multiple steps, a variety of chemicals and a considerable amount of labor. Too often—even when the process is supposedly automated—technicians must still monitor the equipment in person. This usually requires oversight of mixing and separation, the adding of chemicals and other tasks required to keep the process moving. Even then, the water produced can still fall below mandated requirements.
FIG. 1. In contrast to labor-intensive multiple step processes, automated wastewater treatment can help to streamline production, usually with a one-step process. Image courtesy of Sabo Industrial Corp.
Although paying to have industrial wastewater from a cooling tower hauled away is also an option, it is extraordinarily expensive. In contrast, it is much more cost effective to treat the industrial wastewater at its source, at or near the cooling tower. This can enable treated water to be reused, effluent to go into a sewer and treated sludge to pass a toxicity characteristics leaching procedure (TCLP) test, allowing disposal as non-hazardous waste in a local landfill.
Fortunately, complying with wastewater regulations has become much easier with more fully automated wastewater treatment systems. Such systems not only reliably meet regulatory wastewater requirements, but also significantly reduce the cost of treatment, labor and disposal when the proper separating agents are also used.
Cost-effective, automated wastewater treatment. In contrast to labor-intensive, multiple-step processes, automated wastewater treatment can help to streamline production and cooling tower wastewater treatment (usually with a one-step process) while lowering costs at manufacturing facilities.
An automated wastewater treatment system for cooling towers can eliminate the need to monitor equipment in person while complying with mandated requirements. Such automated systems separate suspended solids, emulsified oil and heavy metals, and encapsulate the contaminants, producing an easily de-waterable sludge in minutes.
The water is typically then separated using a de-watering table or bag filters before it is discharged into sewer systems or further filtered for reuse as process water. Other options for de-watering include using a filter press or rotary drum vacuum. The resulting solids are non-leachable and are considered non-hazardous, so will pass all required testing.
These systems are available as manual batch processors, semi-automatic or automatic, and can be designed as a closed-loop system for water reuse or provide a legally dischargeable effluent suitable for the sewer system. A new, fully customized system is not always required. In many cases, it can be faster and more cost effective to add to or modify a facility’s current wastewater treatment systems when feasible.
However, because every wastewater stream for cooling towers is unique to its industry and application, each wastewater treatment solution must be suited to or specifically tailored to the application. The first step in evaluating the potential cost savings and effectiveness of a new system is to sample the wastewater to determine its chemical makeup, followed by a full review of local water authority requirements.
The volume of cooling tower wastewater that will be treated is also analyzed, to determine if a batch unit or flow-through system is required. Other considerations include the size restrictions so the system fits within the facility’s available footprint.
Separating agents. Despite all the advances in automating wastewater treatment equipment, any such system for cooling towers requires effective separating agents that agglomerate with the solids in the wastewater so the solids can be safely and effectively separated out.
Because of the importance of separating agents for wastewater treatment, a special type of bentonite clay in a line of wastewater treatment chemicalsa is used. This line of wastewater treatment chemicalsa is formulated to break oil and water emulsion, provide heavy metals removal and promote flocculation, agglomeration and suspended solids removal.
Bentonite has a large specific surface area with a net negative charge that makes it a particularly effective adsorbent and ion exchange for wastewater treatment applications to remove organic pollutants, heavy metals, nutrients, etc. As such, bentonite is essential to effectively encapsulate the materials. This can usually be achieved in a one-step treatment, which lowers process and disposal costs.
In contrast, polymer-based products do not encapsulate the toxins, so systems that use those types of separating agents are more prone to having waste products leach back out over time or upon further agitation.
Today’s automated systems, along with the most effective separating agentsa, can provide industrial facilities utilizing cooling towers with an easy, cost-effective alternative to remain compliant with local ordinances. Although there is a cost to these systems, they do not require much attention and can easily be more economical than paying fines or hauling.
ABOUT THE AUTHOR
SAL BOUTUREIRA is the Owner of Sabo Industrial Corp., located in Orange County, New York. Boutureira has been an expert in the wastewater treatment industry since 1992. He believes that every place, every waste stream is unique and is passionate about finding the best, customized solution for each problem.