| The sludge was produced in the sewage treatment process, which contains large amountsof organic matter, nitrogen, phosphorus and other nutrients. If being reasonable used, it can beconsidered as a high-quality secondary resources. Therefore, it is very significant andvaluable to carry out the research on its resourceful utilization.The raw sludge of this paperwas taken from a nucleotide plant of Star Lake Company, in Zhaoqing city of GuangdongProvence, which was produced in the sewage treatmen of fermentation residues. This sludge’scomposition was complex and was resourceful. After analyzing the composition features ofthe bio-sludge provided by the nucleotide plant, the solid-state fermentation (SSF) of tropinawas studied with inoculating the strain which can survives the poor living conditions, in orderto improve the protein content and nutrition value of the sludge. Finally, turning waste intosomething useful.First, physicochemical property, nutrient and harmful compositions of biological sludgefrom wastewater treatment in nucleotide factory were studied in this paper. The resultsshowed that the bio-sludge was alkalescent (pH7.34), and its water ratio was higher than82%;the sludge contains lots of nutrient components, such as organic matter（601.68g/kg DW）, TN(50.35g/kg DW),TP(11.71g/kg DW), TK(44.4g/kg DW), TC(27.79%), tropina(14%),while the content of harmful substances was lower than the limits of sludge disposal standard.The concentration of Cu and Cd were lower than the standards-related limits; The Pbconcentration was higher than the limits for afforestation utilization but lower than the limitsof alkali soil for land improvement; contents of Zn, Cr and Ni were higher than the limits ofnational agricultural and industry standards for sludge utilization, and the content of Zn wasthe highest. The results of the speciation analysis showed that the ionic morphology of Cu, Zn,Pb, Ni and Cr were mainly distributed in a stable state, so that their bioavailability was veryweak. The ionic morphology of Cd was mainly unstable state, its bioavailability was strong. Itwas not much effect on the environment because its total contents were much less than thelimits of related standards. The bio-sludge has a resourceful application prospect.The feasibility of using bio-sludge as medium and optimization of the medium in SSFwas studied on the basis of analyzing the composition of bio-sludge. Single factor andorthogonal experiments were carried out in this paper. The best culture medium in SSF asfollows: Aspergillus niger was the best inoculate strain, the ratio of the bio-sludge and wheatbran was3:2,(NH4)2SO43%, K2HPO40.5%. Further, the influence of different factors on theproduction of tropina in SSF process was studied. Box-Behnken experimental was designed basing on the single factor experiment results. The significant influent factors showed in thesingle factor experiment such as the inoculums size, the initial moisture content, as well as themid-term water supplement volume were selected as three factors studied in Box-Behnkenexperimental. After analyzing the RSM, the process optimization was reached: the inoculumssize was3.0ml, initial moisture content was54.45%, the mid-term water supplement volumewas6.75%, temperature30°C, fermentation time was5days. The tropina content in mixturemedium was increase from20.66g/100g dry weight (before fermentation) to32.86g/100g dryweight (after fermentation). |
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