2003 conference paper

Utilization of nutrients in anaerobically-pretreated swine wastewater for greenhouse tomato production

Animal, Agricultural and Food Processing Wastes IX : proceedings of the Ninth International Symposium, 12-15 October, 2003, Raleigh, North Carolina.

By: T. Shearin, J. Cheng*, M. Peet* & D. Willits*

Source: NC State University Libraries
Added: August 6, 2018

Swine waste treatment in North Carolina typically consists of an anaerobic lagoon and sprayfieldupon which crops are grown to utilize the nutrients. Currently, swine lagoon effluent must beapplied at agronomic rates to satisfy the crops nitrogen (N) needs. The majority of landapplication occurs in the summer months, when the weather is typically hot and dry. Agreenhouse tomato production system has been tested for more efficient utilization of nutrients inanaerobically-pretreated swine wastewater. Two 2,600-m2 greenhouses were constructed on a4,000-sow farm located in Johnston County, North Carolina. The swine wastewater was firsttreated in an Ambient Temperature Anaerobic Digester (ATAnD) and the effluent stored in astorage pond. Before being applied to 14,000 tomato plants in the greenhouses, the effluent wastreated in a nitrification biofilter to convert the ammonium (NH4+) into nitrate (NO3-) becausetomato plants prefer the latter as the nitrogen nutrient for their growth. Preliminary data indicatedthat the tomato greenhouses have used approximately 12 m3 of the effluent per day. Based on anaverage inorganic N (NH4+ plus NO3-) concentration of 123 mg/l in the biofilter effluent, thegreenhouses have utilized approximately 1.48 kg N/day. At the same time, the greenhousesproduced a daily yield of 711 kg of marketable fruit, sold at a gross price of $2.20/kg. Thepreliminary findings have shown that the utilization of nutrients in swine wastewater forgreenhouse tomato production is a viable alternative to the traditional system. In addition to thehigh daily N utilization rate, the fruit yields are comparable to conventional greenhouseproduction. Also, the utilization of the treated wastewater during the winter months decreases thepossibility of lagoon overflows and/or spills.