Compost Nutrient Optimization Using Algal Biomass Amendment

Wastewater treatment plants worldwide are a necessary and important function of society. Contaminated water from sewer systems is brought in, filtered, purified, and released back into our rivers and lakes in enormous quantities. The biosolids removed during the many filtration steps are digested anaerobically to produce bio-methane, and then composted with woodchips to be used as a soil amendment, capable of supplying nitrogen, phosphorus, potassium, and other nutrients to plants for agricultural use. Although a value product, analysis of this compost has shown that the nutrient content is low compared to commercial fertilizers. This experiment will show that the addition of an algal biomass grown on a stream of the wastewater can be included in the compost to increase concentration of nitrogen, phosphorus, and potassium while decreasing the toxic concentrations found in the wastewater, and that this inclusion will directly correlate to increased plant growth upon application. Two species of Lactuca Sativa (lettuce plants) grown in the amended compost were used to quantify growth and were compared against a negative control of nutrient-bare soil, and a positive control of the original compost product mixed with soil. Wet mass, dry mass, leaf count, chlorophyll content, root length, and root density were used as growth parameters to quantify differences in the plants