Carrot (Daucus carota) is an important food crop utilized worldwide and its production is associated with byproducts such as culled carrots and carrot waste (i.e., carrot pomace). A variety of technologies aimed at adding value to the byproducts or lessening the environmental impacts of current disposal strategies have been explored in recent years. These technologies encompass physical, chemical, and biological processes and may create products in the form of extracted chemicals, biofuels, novel foods, and adsorbent materials. The objective of this chapter was to review the current trends in carrot production throughout the world; the state of the art in carrot cultivation, harvest, storage, and processing; the production and likely amounts of carrot waste and byproducts; and the application of physical, chemical, and biological technologies to the byproducts. The technologies reviewed are at various stages of commercial development with some already widely commercially available and others farther off in development. The information reviewed here will help in the dissemination of research results of industrial interest to aid in the adoption of relevant technologies in commercial operations.
This study investigated the effects of applying anaerobically digested food waste and dairy manure-derived biofertilizers to processing tomatoes. The biofertilizers were produced from a pilot scale system consisting of coarse solid separation and ultrafiltration (5,000 Da) with a capacity of approximately 3.8 m3*d-1. The coarse solids had particle size greater than 53 µm and were not used for drip fertigation. The liquid concentrate and permeate from the system were both delivered to tomato plants through a subsurface drip fertigation system in a farm-scale cultivation experiment. The results showed that liquid digestate biofertilizers could be effectively delivered to the tomato plants given that steps to ensure suitable particle sizes were maintained prior to delivery. The ultrafiltered dairy manure digestate biofertilizer (DMP) had the highest yield of red tomatoes (7.13 tonne*ha-1) followed by the concentrated food waste digestate biofertilizer (FWC) and mineral N fertilizer treatments with 6.26 and 5.98 tonne*ha-1, respectively. The FWC biofertilizer produced tomatoes with significantly higher total and soluble solids contents compared to the synthetically fertilized tomatoes. Few significant differences between the treatments were observed among the pH, color, or size of the red tomatoes. These results indicate promise for the prospect of applying digestate biofertilizer products to tomatoes using the industry standard subsurface drip fertigation method. Additionally, digestate-derived biofertilizers may have potential to increase crop yields as well as certain quality characteristics of the harvested tomato fruit. No changes in soil quality were found among treatments but more study is required to understand long-term effects of biofertilizer applications with regards to soil quality and environmental risks.
Cultivation of oleaginous microorganisms on wastewater provides alternative biofuel options while also acting as a remediation technique for alternative wastewater treatment. This chapter describes guidelines and methods for the production of oleaginous microorganisms—with a focus on microalgae—using wastewater as a growth medium while considering a variety of general challenges for both lab- and industrial-scale production. Cultivation techniques described here range in scale from microplates with 10-mL working volumes, up to multigallon, industrial-scale microorganism cultivation, with a focus on microalgae. This chapter includes guidelines for the preparation of wastewater and selection of oleaginous microorganisms combined with methods for the production of oleaginous microorganisms cultivated using wastewater.