Sustainability in Operations

During this period of growing concern over climate change and environmental damage, wastewater professionals can take pride in the fact that sustainability is inherent to wastewater treatment. The collection and treatment of wastewater to protect water quality is a critical component of preserving the environment and water resources for future generations. A move toward more holistic management of water, whether driven by the dwindling of water supplies during periods of drought or by limitations on discharges, has resulted in a greater focus on water reuse and the overall value of water.

As the definition of sustainability evolves over time, so too will its impact on wastewater treatment operations. So, what steps can we take to further improve our move toward sustainability? And what will the industry look like in 5 years, 20 years, or 50 years?  In talking with a number of plant operators and other wastewater professionals, some common themes have emerged.

Principally, we can expect a new approach to the design, operation and maintenance of wastewater treatment plants. Optimization of energy, labor, and chemical usage at WWTPs will continue, but different evaluation criteria may dictate the selected practice and the relative importance of a given criterion may shift over time. This will require operators and plant managers to have a broader knowledge of the relationships between  process, equipment and the carbon footprint.  For example, certain modes of operation in activated sludge nitrogen removal processes may produce higher emissions of nitrous oxide than others, which would result in a higher carbon footprint. Some liquid stream and solids treatment processes make better use of the fuel value of wastewater than others. More research is needed in these areas and on other operations related topics. With more information about the full spectrum of “costs”, process selection and operations decisions can be made with a better understanding of the relative importance of different criteria and unintended consequences can be avoided.

Human energy has always been the most important resource in operations and it is through the workforce that many sustainability goals will be achieved. Advancements in technology, such as automation, can reduce labor requirements to some degree but cannot replace the need for experienced operators. As many experienced operators approach retirement, utilities are facing a loss of institutional knowledge as well as manpower. Institutional knowledge can be the key to running a system more efficiently (and thus more sustainably), as well as preventing the kinds of errors that lead to unplanned expenditures and possible environmental harm. The wastewater treatment industry must continue not only attracting newcomers and training them in sustainable practices, but finding ways to equip new operators with this institutional knowledge. Especially now, the industry must be prepared to adjust to shifts in the types of skills required for operations, such as the need for instrumentation and controls specialists.

Finally, wastewater treatment must eventually be integrated into comprehensive water resources management. Operators, plant managers, and utility managers must look beyond a specific part of the plant to the plant as a whole, beyond a single plant to multiple plants within a utility, and beyond the utility to inter-utility partnerships. This is already beginning to happen. For example, many WWTPs within the Chesapeake Bay and Long Island Sound watersheds must be upgraded to meet stringent nitrogen and phosphorus limits. Utilities are conducting studies and sharing the results directly as well as through WEF, the WERF Nutrient Challenge research program, IWA and other member association conferences and seminars. Another example is in Nevada, where the Clark County Water Reclamation District, and the Cities of Las Vegas, North Las Vegas, and Henderson have combined forces to form the Clean Water Coalition to develop a coordinated plan for protecting water resources and water quality. The CWC is working toward implementation of a system conveyance and operations program (SCOP) for a combined discharge to Lake Mead. As part of an overall sustainability plan, the conveyance system includes installation of turbine generators to capture hydroelectric power as a benefit of the elevation difference between the Valley and Lake Mead.

This issue of Water Practice focuses on WWTP operations. It contains a wide variety of articles covering troubleshooting and optimization case studies, operations guides, methodologies for making clarifier operating decisions, and good design practices for ensuring that plants have the facilities needed to meet ever-changing operational needs.  The type of information sharing and communication offered here is of the kind that will be indispensable as the wastewater community turns its attention to sustainable operations.

Chris deBarbadillo, Issue Editor
Black & Veatch