污泥EPS高值、高效提取与回收技术发展趋势

Technical trends in efficient EPS extraction and recovery from excess sludge towards high value-added products

污泥有机质(特别是胞外聚合物,EPS)高值产品回收将会推动污水/污泥资源化.然而,EPS典型提取方法效率较低、回收产物成分复杂,限制了EPS目标物质的高效提取、降低了回收物的潜在高值应用.为此,探究高值、高效EPS提取/回收技术极为重要.这就需要改变目前典型的"笼统"EPS提取方法,将"胞外多糖"和"胞外蛋白"这样的模糊提取物(实为"有机物混合物")转变为单目标物质(如类藻酸盐物质、酸溶性EPS、硫酸盐多糖、淀粉样蛋白质以及透明质酸等)或多目标物质(依靠物理、化学性质差异分离、提纯),实现产物的定向提取并保证其纯度,从而使回收产物获得高值利用.另一方面,把握进水水质、营养物负荷以及运行环境对污泥EPS形成的影响亦十分重要;同时,需要鉴定易形成EPS的优势菌并掌握其生理、生化特征,这对通过污水处理运行而"原位"增加EPS污泥本底含量具有非常重要的意义.此外,还需要针对高值组分进一步发展优化提取方法(如添加表面活性剂等),以实现回收物高效提取与高值回收利用.

Recovering high value-added materials(Extracellular Polymeric Substances,EPS)from excess sludge would promote the resource utilization of wastewater treatment.However,conventional EPS extraction methods are in low efficiency and complicated,which could hinder the highly efficient extraction of targeted materials and thus limit the potential applications of high value-added materials.Under the circumstance,it is extremely urgent to ascertain some more efficient methods for EPS extraction towards high value-added materials.Therefore,it is necessary to change the traditional EPS extraction,from ambiguous EPS(actually"organic mixtures")to single targeted substances like extracellular polysaccharides and proteins(alginate-like exopolysaccharides,acid soluble EPS,sulfated polysaccharides,amyloid-like proteins,hyaluronic acid-like,etc.),or to multi-targeted substances(separation and purification based on the physical and/or chemical differences of targeted materials),which would realize targeted extraction of materials under a high purity for high value-added applications.On the other hand,it is important to know the effects of influent quality,nutrient loads and operational parameters on EPS formation,and moreover is also essential to identify superior bacteria in EPS formation and to know their physiological and biochemical characteristics,which is meaningful for"in situ"improving the content of EPS.Besides,it is expected to further optimize the extraction methods(such as adding surfactant,etc.)for achieving the goal of effective recovery towards high value-added materials.