The Influence of Treated and Untreated Wastewaters on Enzymatic Activity of a Silty Clay Soil Under Laboratory Conditions

The use of industrial wastewater for irrigating farmlands is currently increasing, especially in arid and semi-arid areas because of water shortage for agriculture. The use of industrial wastewater in farmlands could help the sustainable soil fertility through improving the physical, chemical and biological soil characteristics. On the other hand, wastewater may contain toxic elements that are detrimental to soil microorganism and biochemical reactions. The aim of this study was to determine the effects of industrial wastewater either treated or untreated on soil enzyme activities. The wastewater samples were taken from Zobahan, Foolad Mobarakeh Steel Plants and Polyacril plant. Soil samples were moistened at 70% field capacity using wastewaters and then placed at 25 oC for 3months in an incubator. Soil samples were analyzed to examine enzyme activities at monthly intervals. Results showed that during the first two months of incubation enzyme activities increased in wastewater-treated period and sampling time, adding wastewater to the soil increased enzyme activities. The presence of carbon and nutrients in wastewater could lead to an increase in microbial activities and populations, resulted in increasing synthesis and production of enzymes involved