Protecting Lake Erie is a job for all rural Ohioans — New septic systems prevent phosphorus discharge

By Karen Mancl, Professor Food, Agricultural & Biological Engineering, The Ohio State University

With each summer, attention returns to Lake Erie both as a vacation spot and concern for the quality of the water. In the summer of 2014, a harmful algal bloom threated the water supply of thousands of Toledo residents. As a response rural residents and farmers have been asked to change the way they use their land to help protect Lake Erie for the future.

Too many nutrients washing off the land in the Lake Erie watershed help feed the algae. Nutrients come from a variety of sources — fertilizer, manure, and sewage. Septic systems permitted in Ohio are designed to reduce odor and pathogens in wastewater to protect the public health but are not designed to remove nutrients. Discharging systems, even when operated to meet all discharge standards, still discharge phosphorus and nitrogen that flows to Lake Erie in northern Ohio and the Gulf of Mexico in southern Ohio. Curtain drains installed to drain excess groundwater away from septic systems also discharge nutrients to waterways.

Research at Ohio State University studied ways to eliminate the discharge of nutrients from septic systems. The research revealed that year-round onsite irrigation systems are an effective approach. Irrigating the treated wastewater on lawns and landscaping reuses the nutrients to grow plants and keeps nitrogen and phosphorus from discharging into waterways.

Ohio Farm Bureau in partnership with USDA-NRCS, started demonstrating ways that landowners can reduce nutrient loss through Blanchard River Demonstration Farm Network in Northwest Ohio. To demonstrate how all rural landowners can protect Lake Erie, an onsite spray irrigation system was installed at the Stateler Farm in Hancock County. A special treatment system removes the pollutants and kills any bacteria before the clear and odor free effluent is irrigated on the lawn. The new system replaced a 70-year-old septic system that served the family home.

Spray irrigation systems were new to Hancock County, making the demonstration project even more important to show rural residents how they all can protect the lake. The major hurtles for the project were gaining the necessary permits and finding a contractor to install the system. Fortunately, Ohio Farm Bureau and the landowner were persistent in wanting to protect Lake Erie. Through the demonstration project, the local regulators and installers were able to learn what they needed to know to protect both the public health and the lake. The demonstration also makes it easier for local residents to check out onsite spray systems for themselves, so they know what to expect when irrigating treated and disinfected wastewater on their lawn year-round.

Water quality samples collected before and after construction show that 2.06 mg/l of phosphorus being discharged from the old system is no longer making its way to Lake Erie. While that does not seem like a lot, the phosphorus discharged from thousands of septic systems in the Lake Erie basin adds up and is an important source of non-point source pollution. Now all rural residents in the area can protect the lake.

To learn more about onsite spray systems, look for the fact sheet “Spray Irrigation of Reclaimed Wastewater for Rural Homes, AEX-758.” It is available on the website for the Soil Environment Technology Learning Lab —

Karen Mancl is a Professor in the Ohio State University Department of Food, Agricultural & Biological Engineering. This column is provided by the OSU Department of Food, Agricultural & Biological Engineering, OSU Extension, Ohio Agricultural Research and Development Center, and the College of Food, Agricultural and Environmental Sciences, For more information, Mancl can be reached at 614-292-4505 or You can also check her website at

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