微生物絮凝剂提取方法的优化及其对废水中木质纤维类污染物的絮凝机理

利用芽孢杆菌生产的微生物絮凝剂配合助凝剂三价铁，在实际废水的处理中具有良好的应用潜力。为了更好地在实际废水处理中应用微生物絮凝剂，需要优化微生物絮凝剂的提取方法。实验结果表明，通过响应曲面优化法，最终可将微生物絮凝剂的产量由原先的0.5 g·L⁻¹提升至1.64 g·L⁻¹。最佳提取条件为：将培养好的培养液在50 ℃下超声6 min，处理结束后，调节溶液pH在9~11内，然后进行离心、醇沉等操作。微生物絮凝剂对烟草废水COD、氨氮去除率可分别达到50%和28%；对畜禽废水COD、氨氮去除率可分别到达85%和45%。此外，由于微生物絮凝剂的无害性，通过微生物絮凝剂干湿分离后的固体和液体部分可以分别作为有机肥和液体叶面肥再利用，从而可产生一定的经济效益。本研究可为环保絮凝剂的开发与应用提供参考。

Optimization of the extraction method of the bioflocculant and its application in lignocellulosic waste-containing water

Bioflocculant produced by Bacillus is of great potential significance in real wastewater treatment with the aid of ferric iron. In order to make good use of the bioflocculant, it is necessary to optimize its preparation method. Experimental results show, the bioflocculant yields increased from 0.5 g·L−1 to 1.64 g·L−1 by using response surface methodology, and the optimal preparation conditions were as follows: sonication at 50 oC for 6 min, pH 9~11 of the sonicated solution, and followed by centrifugation, alcohol precipitation and etc. The removal rates of COD and ammonia nitrogen in tobacco wastewater treatment were up to 50% and 28%, respectively; the removal rates of COD and ammonia nitrogen in livestock and poultry wastewater treatment were up to 85% and 45%, respectively. Most importantly, this treating method by biofloculant may produce economic benefits: due to the characteristics of harmless and environmental friendly, the solid flocs and the supernatant could be recycled as organic fertilizer and liquid foliar fertilizer, respectively. This research provides new methods and ideas for the development and application of environmentally-friendly flocculants.