Study On Fermentation Technology Of Lake Sediment Bio-organic Fertilizer

Lake sediment is a kind of endogenous contaminants collected from lake bottom, containing a lot of macro molecular organic matter, nutrition and a part of metal oxide, whose direct utilization or stacking will cause secondary pollution. Therefore, this paper aims at exploring in taking lake sediment as raw material to solve this problem by optimum conditions of secondary fermentation bio-organic fertilizer production, while attaining harmless treatment and resource utilization of the mud.Component analysis of lake sediments was conducted, to test its possibility as raw material of bio-organic fertilizer fermentation. The ratio of Bacillus subtilis, Pseudomonas sp., Aspergillus niger and Saccharomyces cerevisiae was determined to 1:1:22 by experiment, then applyed microbial inoculants to first fermentation. To conduct single factor experiment of the bunch frequency, initial moisture content and inoculation amount and taking these conditions as the independent variable, labile organic matter content as response value, then optimized the fermentation conditions by response surface analysis. According to Box-Benhnken central composite design and experiment, used the Design Expert 8.0.6 software by response surface analysis to optimize the fermentation conditions. Finally we obtained the optimal fermentation processing conditions:over bunch frequency 2d/time, inoculation quantity 3.5%, initial water rate 60%. Secondary fermentation was conducted with self nitrogen fixed bacteria Azotobacter Brown spherical, phosphorus bacteria Pseudomonas fluorescens and potassium bacteria ring Pseudomonas aeruginosa according to the ratio of 1:1:1, which inoculated to fermentation product of first fermentation, fermentation lasted 16d. Compared with former fermentation production, available nitrogen, available phosphorus, available potassium content of secondary fermentation production respectively increased 18.6%,21.6% and 10.3%.The optimum fermentation conditions of small test was applied to 1000 m~3 pilot experiment, results showed that taking sediment as raw material, respective indexes of bio-organic fertilizer production of secondary fermentation are all in line with national health standard NY 884-2012, heavy metal content, organic matter, nutrient elements and beneficial bacteria number all attain qualified line, removal of bad smell of the end fermentation production performed well. The application of the bio-organic fertilizer to local kiwifruit orchard showed that bio-fertilizer on soil nutrients and fruit quality had good effects.