Targeted Treatment Systems: More, and Why

In recent years, the field of wastewater management has seen a steady trend toward targeted treatment systems. These include packaged, self-contained, limited process—or even single process—systems for pretreating or treating liquid waste.

This shift is unquestionably counter to the predominant trend throughout the 1960s, '70s and '80s, when larger, multiprocess, end-of-pipe systems tended to handle a grab bag of wastewater.

It's obviously easier to identify a trend in full swing than to predict its onset, but there is no question that we are seeing more targeted treatment systems. While there are examples that would seem to counter this hypothesis—targeted treatment systems, for example, were in play in the '60s, and multiprocess end-of-pipe systems continue to be employed in a number of applications—perhaps the best proof is what predominates when new systems are installed. The answer is clear: targeted treatment.

There are both technological and economic reasons for this, including these factors:

• Lower treatment limits. Particular waste streams have always required isolation and separate treatment by the methods best suited to meeting lower treatment limits. The advance of membrane technology in recent years is an example of how technology has allowed engineers to achieve these lower limits more consistently and economically. In many instances, zero discharge—when required by regulatory limits—can be achieved with targeted treatment systems.
• Material recovery. The opportunity to recover materials is enhanced with a targeted treatment process, which is not encumbered with diverse or incompatible waste materials and uneven wastewater characteristics such as pH, temperature, etc.
• Lower cost. In many cases, the cost to install a low-volume targeted treatment system is less than that associated with a large, multi-process, end-of-pipe system—provided there is not a need for too many separate targeted systems. Cost of treatment is a function of a number of factors, but one of the chief determinants is flow, which can have a significant impact on the size of the equipment. Thus, targeting wastes reduces design flows, which reduces equipment sizes and cost. In many instances, when these targeted systems are located near the source of the waste, operation of the treatment system can be performed by the same people who are operating the manufacturing or production process that is generating the waste.
• New treatment requirements. Today, there is a need to treat flows from sources that may not have required treatment or pretreatment in the past: small labs, high-tech campuses, etc. The small number of wastes from these operations are isolated and managed more efficiently by targeted treatment systems.
• Outsourcing opportunities. For some companies, targeted systems that are closely linked to a manufacturing or production process—whose operations have already been outsourced—can also be outsourced. Single-source responsibility can also be assigned to the manufacturing/production process supplier.
• Lower disposal costs. In general, targeted systems, because they often focus on one or just a few pollutants/chemicals, use fewer treatment chemicals and generate fewer residuals requiring off-site treatment or disposal. This allows an organization to better control their risk.

Despite these advantages, there are instances where targeted systems will not be cost effective—specifically in instances where there has already been a large cost sunk into a multiprocess, end-of-pipe treatment system. Because many such systems were built in the last few decades, investment in targeted treatment systems at these sites probably won't be feasible until stricter treatment limits require it; operating costs become excessive; or the facility reaches the end of its useful life.