May 4, 2022
Improving Water Quality from Home
Research being done at the Blanchard River Demonstration Farm sites is helping researchers determine which conservation practices work best for reducing nutrient and sediment loss. This information is showing farmers and rural property owners what tools and practices they can implement on their farms and within their rural residences to improve agriculture’s impact on downstream water quality in Ohio.
Conventional Septic Systems vs. Wastewater Irrigation Systems
Nitrogen and phosphorus are essential nutrients all living things require. However, an overabundance of these nutrients in both ground and surface water can lead to dense plant and algae growth in lakes and other bodies of water, resulting in toxins in drinking water and excessive nutrient richness in lakes that have been known to cause harmful algal blooms.
In the rural landscape, poorly managed or outdated home septic systems – used to treat human waste and household wastewater – are one of many possible sources that can result in an overabundance of nutrients, such as nitrogen and phosphorus, reaching surface water. In addition, conventional home septic systems are typically not designed to remove phosphorus. According to a study from Ohio State University, “Phosphorus Reduction from Septic Systems,” phosphorus can come from a variety of contributors within the home, such as tap water, the kitchen sink disposal, human waste, and lawn care fertilizer.
With this in mind, the Blanchard River Demonstration Farms Network worked with Ohio State University researchers Mike Rowan and Karen Mancl, as well as other partners, to showcase how rural property owners can reduce nutrient discharge through an alternative septic system – a wastewater irrigation system. In contrast to a conventional system, this option allows wastewater to be reused through lawn and landscaping sprayers after the wastewater has been treated and disinfected.
Benefits of Onsite Wastewater Reuse
- Turns wastewater into clear, odorless effluent for reuse as irrigation for lawn and landscape vegetative growth
- Reduces discharge of nitrogen and phosphorus to groundwater and streams
- Low cost and low energy
Home Septic System Replacement at Stateler Family Farms
With a nearly 70-year-old septic system in need of replacement, the Statelers had two options: replace their existing system with a “new” conventional septic system or install a wastewater irrigation system.
As traditional systems age, there is the potential for environmental degradation. Even if the Statelers replaced their outdated traditional system with a “new” traditional system, the possibility for excessive phosphorus to escape and impact downstream water quality would still exist. Not to mention that existing site conditions were not conducive to a replacement due to poorly drained soils and lack of appropriate depth to treat the wastewater. As a result, fill dirt would have been needed.
In comparison, a wastewater irrigation system would allow the Statelers to filter wastewater, disinfect pathogens and bacteria with ultraviolet light, and pump the treated wastewater through spray irrigation nozzles onto the landscape to be used by growing vegetation. This system reduces nutrient loss off-site that could potentially impact downstream water quality.
Most soils in Ohio don’t allow for traditional leach fields, making alternative sewage systems more prevalent, explains Matt Deaton, a soil scientist with Deaton Soil Services in Eaton, Ohio. “Spray irrigation systems like that used at the Stateler site offer homeowners another option when considering solutions for their properties,” he says. “They’re the only systems where the wastewater is technically reused in an environmentally friendly way, as opposed to just being disposed of.”
Water Quality Improvements
With the installation of an irrigation system at the Statelers, wastewater biochemical oxygen demand (BOD), phosphorus and suspended solids were all reduced. The majority of the phosphorus removal from this system occurs through the spray irrigation system where phosphorus is absorbed by the soil and/or taken up by plants. The removal of BOD, nitrogen and suspended solids occurs prior to spray irrigating. The total cost of the installation, including all components, excavation, and labor for electrical installation, was $28,000.
|Wastewater Parameter||Main Environmental Concern||Conventional Septic System||Wastewater Irrigation System||% Reduction|
|Biochemical Oxygen Demand (BOD)||Harmful to aquatic life||206 mg/l||Not detected||100%|
|Nitrogen, KJELDAHL||Surface and groundwater pollutant; lake eutrophication (algal blooms)||21.5 mg/l||Not detected||100%|
|Nitrogen, Ammonia (NH3, NH4+)||Toxic to aquatic life||3.26 mg/l||0.39 mg/l||88%|
|Nitrogen, Nitrate + Nitrite (NO2-, NO3-)||Surface and groundwater pollutant; algal blooms; Infant Methemoglobinemia (Blue Baby Syndrome)||Not detected||7.5 mg/l||N/A|
|Phosphorus||Surface water pollutant; lake eutrophication (algal blooms)||2.06 mg/l||1.94 mg/l||6%|
|Suspended Solids||Increased BOD and phosphorus transport; harmful to streambed habitats||372 mg/l||7 mg/l||98%|
Source: Jones & Henry Laboratories, Inc.
Water quality samples were collected at the Statelers prior to the new wastewater irrigation system installation and four months after installation. Upon completion, each wastewater parameter saw a reduction in nutrients with the exception of nitrogen. Within the irrigation system, organic nitrogen is converted to ammonia, which naturally converts to nitrite and nitrate. This explains the increase in nitrate and nitrite from not detected to 7.5 mg/l because the irrigation system provides for the complete cycling of nitrogen.
To learn more about the conservation practices improving agriculture’s impact on downstream water quality in Ohio, please visit our practice pages.