Maximizing Your Monitoring Power

Online water-quality analyzers offer time-saving solutions for dealing with pending EPA regulations related to nutrients in wastewater and water

• By M. Y. Z. Aboul Eish, Ph.D., Robert H. Clifford, PhD
• Oct 01, 2007

As water and wastewater facilities prepare for pending U.S. Environmental Protection Agency (EPA) criteria on water nutrient levels, online monitoring systems are proving to be an effective and efficient means of regulating the parameters.

Water nutrient guidelines originate from the Clinton administration’s Clean Water Action Plan, which led to a national strategy to develop nutrient criteria in lakes, streams and rivers. On June 25, 1998, the notice of the National Strategy for the Development of Regional Nutrient Criteria was published in the Federal Register (Volume 63, Number 122, pages 34648-34650). In the plan, the government called on EPA to accelerate the development of scientific information concerning the levels of nutrients that cause water problems. EPA’s goal is to accelerate the progress of state adoption of numeric water quality standards, while building the scientific and technical infrastructure for developing new nutrient criteria. Once established, numeric standards reduce states’ time and effort to establish total maximum daily loads and permits to control nutrient levels.

The Trouble with Nutrients
Overuse of fertilizers, which contain three basic plant nutrients -- nitrogen, phosphorus and potassium -- has resulted in the increasing contamination of surface water and groundwater. Although these nutrients are critical to the development of plant and animal life, they have the potential to be harmful if ingested by humans and animals.

Nutrient-rich ponds and streams undergo eutrophication, water pollution caused by excessive plant nutrients. This process depletes oxygen levels in water, causing an accelerated growth of algae in the waterways. Algae then can cloud the water, effectively blocking sunlight from submerged aquatic vegetation. Excessive algae also can decrease biological diversity and populations, resulting in diminished populations of game and commercial fish.

While the risks of excessive nutrients are many, too few nutrients may result in insufficient enrichment of the aquatic food chain, which would be detrimental to a healthy aquatic biological community.

Considering the hazards posed by undesirable nutrient levels, EPA and state agencies have begun refining and implementing adequate water quality standards to provide goals for industries to reduce their outflow of nutrients such as nitrogen and phosphorous into waterways. Permits are being issued for facilities that regulate discharge and will soon be required to meet the set standards.

So Long to Tradition
Water-quality analyzers have been an integral part of industrial and wastewater treatment applications for years. However, the traditional water analyzing techniques are manual, costly, timeconsuming and often inaccurate.

In addition, the samples are sent to a laboratory for nutrient level testing, which can take several days or even up to a week for results. This means that if the sample is contaminated, there is a delay in treating the water. These delays make it difficult to effectively optimize and control treatment processes.

In an effort to reduce the labor and cost, many facilities have dramatically cut the number of hours specified for the monitoring process. Because less time is being dedicated to the monitoring process, less information is being

provided about nutrient levels. Therefore, water has the potential to be overtreated or even undertreated. Additionally, a reduction in sampling hours means that pertinent criteria regarding nutrient levels may not be made readily available.

As facilities seek greater analyzing effectiveness through alternative techniques, a new breed of sampling and treatment equipment has entered the market. Automated online sampling is rapidly gaining recognition for various measuring and operational tasks in both the water and wastewater sectors. New Technology Yields Better Results Online monitoring technology enables real-time monitoring of water and wastewater for municipal and industrial applications. Less cumbersome than conventional methods, online analyzers are easy to operate and specifically intended to prepare facilities for the EPA’s pending nutrient level regulations.

With online technology, a computercontrolled system automatically pumps water samples to the analyzer in the facility lab. The time-saving technology provides comprehensive water quality analysis onsite, eliminating the need to manually collect the samples. In addition, results from onsite analytical instrumentation are obtained quickly, and there is no need for outside laboratory testing. Because of the minute-tominute analyzing capabilities of the single- unit technology, more details are provided about nutrient levels within the day. The red circle in the chart indicates a sudden change in relative total phosphorous, one that may not have been detected with manual monitoring (Figure B).

Online analyzers are capable of simultaneously measuring specific nutrients such as total nitrogen and total phosphorous in water. This device also comes equipped with calculators that act as an alarm for specific actions such as error checking. In addition, the online technology can pretreat, digest, and analyze samples automatically, and eliminate errors in sample preparation.

Through an automated monitoring and analysis process, the analyzers provide facilities with advanced technology that helps accelerate the reduction in pollutants discharged and minimizes the health risk involved accordingly. These online sampling devices, which provide continuous monitoring, also reduce the energy, resources and materials used in the sampling process.

An Effective Solution
Removal of nitrogenous compounds from water and wastewater is critical, as excessive nitrate levels in discharged effluent can pose a threat to our environment. With new requirements to control nutrient discharge currently under way, effectively monitoring nutrients in water and wastewater will become increasingly important.

Automated continuous sampling devices are proving to be a reliable and easy environmental monitoring tool, providing a good and economical option to traditional techniques.

This article originally appeared in the 10/01/2007 issue of Environmental Protection.