Process Scale-up for Rapid Naphthenic Acid Removal from Oil sands Process Waters (OSPW).

随着全球轻质原油储量的生产预计将持续约50年，需要开发替代燃料资源，例如油砂。北美和南美巨大的油砂资源已经被开采，造成大规模的环境污染。在从油砂中提取沥青的过程中，会产生大量的废水（尾矿），这些废水储存在巨大的沉淀池中。目前，仅在加拿大就积累了约8.4亿立方米的尾矿。尾矿池有几个问题：排放大量的生物源温室气体（例如，一个池每天排放43，000立方米甲烷），它们的细粒尾矿固体固结（沉降）非常缓慢，这可能需要几十年。尾矿储存由于存在高浓度的被称为环烷酸（NAs）的有毒化合物而造成巨大的环境风险。NAs是脂肪酸和芳香酸的复杂混合物，对包括人类在内的许多生物体具有高毒性。NA还堵塞/腐蚀管道/加工设备，造成进一步的污染和数十亿美元的损失。因此，去除NA污染对全球经济、环境和人类健康至关重要。微生物处理NAs具有明显的成本-环境优势。然而，NAs的转化是复杂的，并受到微生物相互作用，生态地球化学因素和NAs的物理化学性质的组合的影响。我们以前的工作表明，更多的柠檬酸NAs具有高分子量，并高度支化。这是环境问题，因为这些更高度支化的NA可能在环境中积累。最近，我们开发了一种生物反应器，在几天内实现了87%的NA去除。我们的生物反应器处理还提高了尾矿沉降率。虽然我们的原型砾石床生物反应器是在实验室规模上快速去除NAs的一个重大进步，但我们缺乏关于它是否可以在现场规模的处理条件下和使用几种不同的废物进料有效地操作（用于NA去除和解毒）的信息。由于每个操作者使用不同的NA提取方法，因此产生的废水具有不同的物理化学特性，并且含有不同的NA组成/浓度。因此，至关重要的是在放大过程中测试生物反应器技术，并测量NA去除，解毒和增加沉降的效果，与不同的废水有关。一旦在实地规模的试验中得到验证，该技术将使运营商能够回收废水，提高沉淀率，减少尾矿储存量，从而降低资本/储存成本和环境风险。我们建议的项目涉及一个国际合作，它整合了阿尔伯塔油砂尾矿研究设施（OSTRF）的工艺放大设施和专业知识，卡尔加里大学（UoC）的工艺放大建模和分析化学专业知识和设施，以及现场和不同工艺进料的访问（杜邦、Syncrude、Suncor（通过UoC）、壳牌加拿大公司（通过阿尔伯塔环境部（AE）和通过阿尔伯塔政府监管机构（AE）向最终用户提供技术的专业知识。总体目标：将我们优化的生物反应器技术和工艺发展成一个具有成本效益的系统，可以在现场规模上从不同的废水中去除NAs（数量和毒性）。具体目标：1）量化生物反应器对NA去除和NA解毒的有效性（包括代谢物毒性）2）研究生物反应器技术在各规模下提高沉降速率的有效性; 3）表征处理期间（在每个规模下）微生物群落结构的变化，以确保始终保持微生物群落的完整性。

With worldwide production of light crude oil reserves expected to last ~50 yrs, there is a need to exploit alternative fuel resources e.g. oil sands. The vast oil-sand resources in N & S America are already being exploited, resulting in large-scale environmental pollution. During bitumen extraction from oil sands, large volumes of wastewaters (tailings) are produced that are stored in vast settling ponds. Currently ~840 million m3 of tailings have accumulated in Canada alone. There are several problems with tailings ponds: vast amounts of biogenic greenhouse gases are emitted (e.g. 43,000 m3 / day CH4 from one pond), they have very slow consolidation (settling) of the fine tailings solids, which may take decades. Tailings storage poses huge environmental risks due to the presence of high concentrations of toxic compounds known as naphthenic acids (NAs). NAs are complex mixtures of aliphatic & aromatic acids that are highly toxic to many organisms including humans. NAs also block/ corrode pipes/ processing equipment causing further pollution and billion-dollar losses to the industry. Thus, removing NA contamination is important to the global economy, environment and human health. Microbial treatment of NAs has clear cost-environmental advantages. However, the transformation of NAs is complex and influenced by a combination of microbial interactions, biogeochemical factors and the physical-chemical properties of the NAs. Our previous work showed the more recalcitrant NAs have high molecular weights, and are highly branched. This is of environmental concern as these more highly branched NAs may accumulate in the environment. Recently, we developed a bioreactor that achieved 87% NA removal within days. Our bioreactor treatment also increased tailings sedimentation rates. Although our prototype gravel bed bioreactor is a significant advance for the rapid removal of NAs on a lab-scale, we lack information as to whether it can operate as efficiently (for both NA removal & detoxification) under field-scale processing conditions and with several different waste feeds. Since each operator uses a different NA extraction method, the resulting wastewaters have different physical-chemical characteristics and contain different NA compositions/concentrations. It is thus crucial to test the bioreactor technology in a scale-up process and measure the efficacy of NA removal, detoxification and increased sedimentation, in relation to different wastewaters. Once validated under field-scale trials, the technology will allow operators to recycle wastewater, increase sedimentation rates and reduce the amount of stored tailings, thus reducing capital/ storage costs and environmental risk. Our proposed project involves an international collaboration that integrates the process-scale-up facilities and expertise at the Oil Sands Tailings Research Facility (OSTRF), University of Alberta (UoA), expertise and facilities in process-scale up modeling and analytical chemistry, University of Calgary (UoC), access to field sites and different process feeds (DuPont, Syncrude, Suncor (via UoC), Shell Canada pus other operators (via Alberta Environmental (AE) and expertise for implementing the technology to end users via the Albertan Government Regulator, AE. Overall aim: to develop our optimized bioreactor technology and process into a cost-effective system, that can remove NAs (both amount & toxicity) from different wastewaters at the field-scale. Specific Aims: 1) To quantify bioreactor effectiveness for NA removal and NA detoxification (including metabolite toxicity) from different wastewaters (i.e. from different operators) at lab-, intermediate and field-scale; 2) To investigate the effectiveness of the bioreactor technology for increasing sedimentation rates at each scale; 3) Characterize changes in microbial community structure during treatment (at each scale) to ensure microbial community integrity is maintained throughout.