Utilization of wastewater and wastewater sludge for production of value added products

污水处理厂每天产生大量的污泥。污泥处理及其安全处置是一个昂贵且环境敏感的全球性问题。为了从循环经济的角度促进可持续的污泥管理，迫切需要通过从废水污泥中创造增值产品来制定可行的资源管理方案。在这种情况下，我们研究的长期目标是利用废水污泥作为混合微生物群落的来源，同时产生三种产品，即胞外多糖（可用作生物絮凝剂的EPS），生物塑料（聚羟基脂肪酸酯或PHA）和脂质（生产生物柴油）。最近，我们的研究表明，废水污泥中含有多种类型的微生物，可以同时合成这三种产物。生产EPS和生物塑料的微生物非常丰富。虽然产生脂质的微生物相对较少，但脂质是所有类型的污泥微生物的细胞膜的组成部分。因此，如果在特定的微生物培养条件下向污泥微生物提供适当的碳源，则可以同时合成这三种产物，同时使其他不需要的微生物（不产生这些产物并且存在于污泥中的微生物）的生长最小化。 活性污泥）。 因此，拟议研究的主要目标是开发一种创新的和经济上可行的工艺，使用活性污泥作为微生物的来源和不同的废物作为碳源，同时生产这些产品。 本研究计划的具体目标包括：分析微生物污泥群落;确定合适的培养条件，优化工艺参数以提高产品的产量;使用不同的碳源并研究其对产品组成和分子量的影响;以及开发合适的方法回收增值产品。生产的生物塑料的分子量很重要，因为这决定了由生物塑料制备的最终可销售产品的质量。该研究的成功完成将允许开发一种新的生物塑料，生物絮凝剂和脂质的经济生产工艺，并最终促进环境友好，可持续的污泥管理和零废物概念。新工艺将减少对昂贵发酵罐的需求，其复杂和昂贵的操作，并最大限度地降低生产成本。此外，这项研究非常及时，将 帮助加拿大工业发展生态友好，商业上可行的生物塑料，生物絮凝剂和脂质，从而加强加拿大的环境政策和零废物概念。

Wastewater treatment plants produce large quantities of sludge every day. Sludge treatment and its safe disposal is an expensive and environmentally sensitive problem worldwide. To promote sustainable sludge management in the perspective of circular economy, there is an urgent need to develop viable options for resource management through the creation of value added products from wastewater sludge. In this context, the long-term goal of our research is to produce value added products using wastewater sludge as a source of mixed microbial community to generate simultaneously three products namely extracellular polysaccharides (EPS that can be used as bioflocculants), bioplastics (Polyhydorxy alkanoates or PHA) and lipids (to produce biodiesel). Recently, our study demonstrated that wastewater sludge contains numerous types of microorganisms that can simultaneously synthesize these three products. The EPS and bioplastics producing microorganisms are in abundance. Whereas lipid producing microbes are present comparatively to a lesser extent, but lipids are an integral part of the cell membrane of all types of sludge microorganisms. Thus, if a proper carbon source is supplied to sludge microorganisms under specific microbial cultivation conditions, these three products can be simultaneously synthesized while minimizing growth of other unwanted microorganisms (that do not generate these products and are present in activated sludge). Therefore, the principal objective of the proposed research is to develop an innovative and economically viable process for the simultaneous production of these products using activated sludge as a source of microorganisms and different waste materials as carbon source. The specific objectives of the present research program include: analysis of the microbial sludge community; determine proper cultivation conditions, optimization of the process parameters to increase the yield of the products; use of different carbon sources and study of their impact on the composition and molecular weight of the products; and development of a suitable method for recovery of the value-added products. The molecular weight of the bioplastics produced is important because that determines the quality of the final marketable products prepared from the bioplastics. The successful completion of the research will allow to develop a novel process of economical production of bioplastics, bioflocculants and lipids concomitantly and it will eventually promote environment friendly, sustainable sludge management and zero waste concept. The new process will obviate the need of expensive fermenters, their sophisticated and expensive operation, and minimize the production cost. Further, this research is very timely and will aid Canadian industry to develop ecofriendly, commercially viable bioplastics, bioflocculant and lipids and thus strengthening Canada`s environmental policy and zero waste concept.