Those involved with wastewater treatment are aware of the challenges faced through ever-tightening regulations regarding nutrient discharge to waterways. The Chesapeake Bay and Lake Erie are two examples of waterbodies having received media attention for issues such as hypoxia (low oxygen levels) which is related to nutrients. Even though experts agree that 60-75% of the nutrients come from agriculture, wastewater treatment has been identified as the solution provider to this sizable problem. In some cases, limits imposed on municipal wastewater treatment plants are lower than what the available amelioration technology can achieve. And it’s not uncommon to expect virtually unlimited investment in the search for solutions.
But most lay people are unaware of nutrient issues, also known as eutrophication, let alone the efforts underway to address them, such as water quality trading and adaptive management. Fewer people, including wastewater treatment professionals are unaware, as I shared three years ago, using disposers can reduce nutrients discharged from treatment plants.
Water quality trading and adaptive management
What is water quality trading and adaptive management? Both are strategies instituted by regulators to help municipalities meet compliance with low nutrient discharge limits. According to the Wisconsin DNR, water quality trading is used to offset treatment plant discharges, to comply with permit limits. It pertains to reducing nutrients from other sources in the watershed instead of reducing the effluent discharge. Adaptive management, on the other hand, focuses on achieving water quality criterion (acceptable background levels) and emphasizes overall reduction. How much success either offers depends on the measurement used to gauge them.
Both are being forced on municipal treatment plants in an effort to reduce nutrients coming from agriculture. In fact, most of the water quality trading and adaptive management strategies are specifically employed in the agriculture sector and yet – they are paid for by municipalities.
Image: World Resources Institute
Food production thanks to fertilizer
U.S. farmers are tremendously successful at food production largely due to fertilizer use (nutrients) which, by the way is a limited resource (see Phantastic Phosphorus). This overproduction via fertilizer ends up polluting waterways. Then the wastewater sector has to pay for remediation. We all need to understand the price for the luxurious grocery store selection we expect. This abundance is one of the reasons rates are increased by the treatment plant. Unfortunately, we live in a society that largely takes food availability and its consequences for granted. So what is to be done? It’s a big problem requiring big solutions, right? Maybe not.
Starting small instead of big
Some argue that small-scale steps taken by small agriculture can be more productive than grand initiatives and costly treatment plant investments. This makes sense, especially when the cost of remediation at the treatment plant using the “best available technology” is much more expensive and yields a much lesser reduction – a concept explained by Maria Laukkanen and Anni Huhtala in their paper, “Optimal Control of Nutrient Pollution in a Coastal Ecosystem: Agricultural Abatement vs. Investment by Wastewater Treatment Capacity.” However, I still struggle with placing the burden of managing the reduction of nutrients on one industry, when a majority of the problem comes from another.