| Fishmeal processing wastewater contains high organic substance (30-120 g COD/L), high protein content (2-5%), high salinity (> 10 g/L), high viscosity and a large number of fish broken body. Morever, because such wastewater produces only in part of coastal areas, and the investment on processing technology research is insufficient. Finally, leading to the fishmeal wastewater treatment has been a difficult problem of sewage disposal areas. At present, the domestic and foreign to fishmeal wastewater treatment means more than for a single physico-chemistry/biochemical treatment method and simple combination of physico-chemistry and biochemical process. So far, lack of effective combination of the physico and biochemical treatment technology.This paper was carried out to investigate the typical fishmeal wastewater. Aiming at this kind of wastewater quality features, developed some pertinently studied on two aspected on resource-oriented utilization and low cost process. Based on the water quality characteristics of fishmeal wastewater, intends the following process: coagulationâ†'microbial lipid productionâ†'anaerobic granular sludge treatment processâ†'hydrolysis extraction of amino acids. First, used coagulation method to recycle the colloidal and suspended organic materia from wastewater. Second, inoculate the yeast to wastewater and use the rest of soluble material for lipid production, then using anaerobic biological treatment, while applying anaerobic hydrolysis extraction of amino acids before the anaerobic process, in order to achieve the maximum recovery of useful substances and mitigate the anaerobic load. It also studied the optimal operation index of every process and the main conclusions are as follows:(1) The coagulation was used as the pretreatment step of fish protein recovery. Under the condation of pH=7, the dosage of PFS (600 mg/L), rapid stir speed grade (200 r/min for 120 s), slow stir speed grade (80r/min for 8 min), COD and suspend solids were 45.5% and 92.4%, respectively.(2) Using fishmeal wastewater (FW) as a novel medium to produce Microbial lipid by strain Lipomyces starkeyi HL. The experimental results showed that The experimental results showed that when no additives adding, initial pH was 6.5, after cultured for 6 days, production of 5.34 g/L of biomass containing 1.1 g/L lipid were obtained; Addition of 20 g/L glucose at initial pH 4.0 obtained the best results:17.6 g/L of biomass,2.7 g/L of lipid yield and 43.4% of COD removal. The main composition of fatty acid in the resulted lipid were myristic acid (C14:0) and palmitic acid (C16:0). Appling homogenous experimental design, when adding 4 g/L H2O, lipid yield increased 30.1% with the reference group, indicating that the content of Mn2+ has a significantly influences on lipid yield.(3) Utilizing anaerobic granular sludge to treat the coagulated fishmeal wastewater, when the influent organic loading rate was 7.5 kgCOD/(m3·d), the removal rate of COD is 86%. The high salinity level of fishmeal wastewater had a significant inhibition efffect on granular sludge. When the wastewaters sodium concentration varied from 0.52 to 7.6g/L, no activity inhibitions were observed according to the analysis of granular sludge performance. At sodium concentrations over 9.0g/L the negative influence of salinity on microorganisms was observed in reactor, which resulted in decreased COD removal rate and reduced granule strength. The formed granular sludge was black ellipse and grain, size distribution was between 0.3-3 mm, the sludge density was 25 g MLSS/L, the sedimentation rate was 53-140 m/h.(4) Salting-out extraction of amino acid experiment shows that, under the condation of influent COD=18 g/L, hydrolysis time of 5 h, the resulted amino acid was 2.7 g/L. After supplied of 5 g/L CaCl2, pH adjusted to 9, the extraction rate of amino acid and the removal rate of COD were 31.6% and 37.7%, respectively. |
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