Use of Wastewater and Compost Extracts as Nutrient Sources for Growing Nursery and Turfgrass Species

Abstract

Nutrient salts present in liquid by-products following waste treatment are lost resources if not effectively recycled, and can cause environmental problems if improperly disposed. This research compared the growth response and mineral nutrient status of two nursery and two turfgrass species, hydroponically supplied with nutritive by-product extracts derived from anaerobically digested municipal solid waste (MSW) and aerobically composted organic wastes from the mushroom and MSW industries. Forsythia (Forsythia x intermedia 'Lynwood') and weigela (Weigela florida 'Red Prince'), and creeping bentgrass (Agrostis palustris Huds.) and Kentucky bluegrass (Poa pratensis L.), were grown in nutrient solutions/extracts prepared from: (i) half-strength Hoagland's #2 solution (HH; control), (ii) Plant Products liquid fertilizer (PP; g kg(-1): 180 N; 39 P; 224 K), (iii) spent mushroom compost (SMC), (iv) MSW compost (GMC), and (v) intra-process wastewater from the anaerobic digestion of MSW (ADW). Additional nutrient solutions (SMC-A, GMC-A, and ADW-A) were prepared by amending the original solutions with N, P, and/or K to concentrations in HH (mg L(-1): 105 N; 15 P; 118 K). Plants receiving the SMC-A extract grew best or at least as well as those in HH, PP, and the amended GMC-A and ADW-A solutions. This study indicated that, with proper amendments of N, P, K and other nutrients, water-soluble constituents derived from organic waste treatment have potential for use as supplemental nutrient sources for plant production.

A Conceptual Framework for Incorporation of Composting in Closed-Loop Urban Controlled Environment Agriculture

“…Other challenges associated with using compost extracts as nutrient solutions include drastic variations in pH, nutrient level management, electrical conductivity (EC) regulation, and associated yield reductions [205,206]. The compost extracts cannot be used directly due to the possible imbalances in the nutrient profile and chemical characteristics of the untreated extracts.…”

“…The compost extracts cannot be used directly due to the possible imbalances in the nutrient profile and chemical characteristics of the untreated extracts. The imbalanced nutrient profile of the compost leachate affects the growth and nutrient composition of the plants [205,207]. Thus, using compost extract as nutrient solution requires regular monitoring and fortification of deficient nutrients to ensure proper nutrient availability and plant growth.…”

“…Thus, using compost extract as nutrient solution requires regular monitoring and fortification of deficient nutrients to ensure proper nutrient availability and plant growth. Compost extract used as hydroponic nutrient solution also shows significant fluctuation in pH due to nutrient uptake, variation of NO 3 − /NH 4 + balance and low buffering capacity [205]. Hence, achieving proper plant nutrition with compost-based nutrient recovery will continue to require some level of mineral fertilizer input.…”

Technical Challenges and Optimization of Biogas Plants

“…Decrease in costs of conventional energy sources [22][23][24][25][26] 4. Reduced expenditures for chemical fertilizer [27][28][29][30] 5. Increased opportunity for (small scale) animal husbandry [31,32] 6.…”