A life cycle assessment of biosolarization as a valorization pathway for tomato pomace utilization in California

The California tomato processing industry produced circa 388,856 t of tomato pomace in 2014. While currently used for animal feed, tomato pomace could be utilized for biosolarization. Primary Energy Demand (PED) and Global Warming Potential (GWP) equivalent emissions were calculated for two valorization pathways: (i) feed for cattle; and (ii) biosolarization. In order to make these two valorization pathways comparable three management options were analyzed whereby each part of the system was satisfied, i.e. a pest management sub-system and a cattle feed sub-system. The management options were (1) tomato pomace used for cattle feed and soil pest control using fumigant Telone II and herbicide glyphosate; (2) tomato pomace used for cattle feed and soil pest control using solarization; (3) alternative cattle feed (cottonseed, canola pellets and wheat straw) and soil pest control using biosolarization with tomato pomace. Options 2 and 3 result in a reduction of GWP and PED. Among management options, the GWP ranged from 64-98 kg CO2-e and 1502-2250 MJ for PED per t of pomace. The majority of impacts were beyond the tomato processors' immediate control, therefore encouraging the diversion of tomato pomace to biosolarization may be desirable. Total savings per annum for biosolarization could be as large as 7.7 M kg CO2-e and 203,000 GJ annually.