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Experts at International Cover Systems Inc. discuss two major applications of geomembranes for agriculture that protect the environment.
Many of us love meat and dairy, but most put little thought into the waste produced by the animals that bring us these tiers of the food pyramid. The U.S. Department of Agriculture estimates that the United States produces 335 million tons (304 million tonnes) of manure annually—and that is dry weight. Geomembranes for agricultural applications, such as agricultural storage ponds and agricultural treatment lagoons, can provide critical protections for the environment, making manure talk a little more palatable for farmers and consumers
Geomembranes for agriculture: Agricultural storage ponds
A storage pond is an earthen structure designed to hold waste until biological processes have digested it to the point that it can be applied to farmland. Inputs can range from manure and bedding, to wash water and rainwater runoff. Geographical location, weather and local regulations dictate the length of holding time, which can range from three to six months.
While storage ponds are smaller and less expensive to construct and to line than treatment lagoons, they need to be emptied and cleaned more often, depending on the pond’s volume and waste inflow rate. Storage pond slurry is more nutrient-dense than lagoon effluent, and it is, therefore, more valuable per unit for growing crops. That additional nutrient value comes with an equal amount of odor, making it pivotal to incorporate storage pond slurry into soil quickly after application to farm fields.
Geomembranes for agriculture: Agricultural treatment lagoons
Much larger in geographical size and holding capacity, agricultural treatment lagoons provide additional treatment benefits to the storage they provide. Part of this increased storage capacity is used to dilute waste to concentrations necessary for the wanted biological processes and treatment to take place. Additionally, a treatment lagoon’s volume must account for the accumulation of sludge that collects and settles in the bottom as biological processes digest waste.
The various benefits treatment lagoons provide can outweigh additional costs of construction and lining. First, the biological processes in lagoons stabilize the contents, lessening malodorous smells as compared to storage ponds. Second, the treated liquid effluent from a lagoon has a lower nutrient content than the slurry from a storage pond. This means less land is required for application of lagoon contents versus the output of storage ponds. This remains consistent apart from years when the sludge at the bottom of a lagoon is cleaned out.
Lagoon sludge is denser in phosphorous and other minerals than the effluent it produces.
Geomembranes and the environment
Collecting and containing agriculture waste is imperative for the health and sanitation of farm animals. It is equally important for the health of our environment. Runoff from stormwater and snowmelt can transport manure to surface and groundwater, along with any pollutants it contains.
Manure holds a myriad of pathogens, such as e. coli and salmonella, that could make animals and humans sick if they meet it either directly or within the environment. The nutrients that are so beneficial in fertilizing crops can also be a detriment if they are introduced to waterways. Increased nutrients within aquatic ecosystems results in excess plant growth, including algal blooms as shown in Figure 2. This can cause issues for water flow rates and fish passage by physically clogging streams, creeks and rivers.
Excess plant growth can also cause “dead zones” within lakes and estuaries. As aquatic plants die and decompose, they produce carbon dioxide as a byproduct. For areas of excess plant growth, this can mean zones where aquatic animals cannot survive within its boundaries.
The addition of properly installed geomembrane lining systems in the construction of agriculture storage ponds and treatment lagoons are imperative for the safety of the environment. These systems provide watertight containment and safeguards not provided with unlined designs. This ensures no waste escapes that could potentially enter surface or groundwater, causing contamination and degradation of the surrounding ecosystem.
Choosing the best liner
Appropriate geomembrane liners for agricultural storage ponds and treatment lagoons range from 60-mil (1.5-mm) high-density polyethylene (HDPE) to fabricated 36-mil (0.9-mm) reinforced polypropylene, meeting NRCS guidelines. ICS has extensive knowledge in the agricultural waste industry and can assist with the planning, design, and installation of geomembrane liners. With a wide variety of materials available for different types of impoundments, ICS can help you decide the best approach to your lagoon while meeting all Federal, State, and local regulations. Contact ICS to help get your agricultural poop in a group!
This article originally appeared on the International Cover Systems Inc. blog.