In many rural, agricultural areas there is no nearby access to rivers or oceans for drain water disposal. Evaporation ponds offer a very cost-effective solution in these situations. Land is typically affordable in these areas, providing the ability to purchase ample space. The evaporation greatly reduces costs by lowering the volume and weight of waste requiring treatment. Wastewater, from farming, can contain many contaminates that are harmful to the soil and our environment. These pollutants include fertilizers, pesticides, crop residue and even animal waste. Therefore, it is very important to deal with the runoff properly.
Agricultural evaporation ponds are easy to construct. Multiple, shallow ponds should be built with careful locational planning. Drain water can be either easily fed to the ponds by gravity or piped to their location. These ponds should be close together, partitioned with levees between them, lined with a quality multi-layer RPE liner and designed to hold water at a maximum depth of three feet. Highest evaporation rates will be achieved when it is sunny, windy and the temperature is over eighty degrees. If conditions are not optimal, water mist evaporation may be employed. These systems help boost evaporation with the use of a misting unit that floats on top of the water. They can increase evaporation by up to 20%, but can be expensive, so be sure to weigh the benefits verses the cost.
After evaporation has greatly reduced water volume over time, the byproducts will remain at a highly concentrated level. These byproducts should be evaluated on a case specific basis. Some byproducts will need further treatment for disposal, while some may be collected for commercial use. Depending on the contaminates, it is possible that you will may encounter some unpleasant odors throughout the evaporation process. In that case, there are many options to help. Filters, scrubbers, washing towers and even regenerative thermal oxidation methods will help significantly reduce the unpleasant smell.
