Evaluation of the possibility to use organic acids solutions for production of fertilizers based on horticultural mineral wool waste

Abstract

The aim of the research was evaluation of the possibility to use organic acids solutions for production of fertilizers based on mineral wool waste. This substrate thanks to inert character and good air-water relationship is commonly used in greenhouse industry. Increased production of vegetable in soilless culture due to world’s population growth. However mineral wool after full crop cycle is non-biodegradable – dangerous waste. Possibility of extraction nutrients from this kind of substrate could be solution of that important environmental problem. Before analyses mineral wool waste was grinded on 0.40 mm sieve. Then the extraction process was conducted using 2 % m/m and 10 % m/m citric acid, 2 % m/m and 10 % m/m formic acid, 0.2 % m/m and 2 % m/m acetic acid for 3 and 6 hours at temperature 25 C. Solid phase before analyses was mineralized. Iron, phosphorus was analyzed using spectrophotometer methods. Iron analysis is based on formation of a coloured ferric ion complex with 2,2’-bipyridyl. Phosphorus analysis is based on formation of molybdenum blue complex. Calcium and magnesium was examined by complexometric titration with EDTA and using Eriochrome Black T as an indicator, while calcium ions concentration was analyzed using calconcarboxylic acid as an indicator. Content of nutrients after extraction from mineral wool waste allows to conclude that obtained liquid phase can be used as a fertilizer component while solid phase can be used in mixed substrate production.