Innovative approaches for metal removal from petroleum desalter effluent using biological systems

原油脱盐脱水是原油蒸馏装置（CDU）上游原油脱盐脱水的重要单元操作。该装置操作产生的脱盐废水含有许多污染物，如碳氢化合物乳液、重金属、氯化物和碳酸盐等盐、悬浮固体、硫化氢（H2S）、氨和酚类化合物。目前脱盐废水处理的方法包括沉淀法去除污泥和悬浮固体，溶气浮选法去除油和/或膜/反渗透法去除金属。然而，这些技术效率低下且昂贵。脱盐废水中重金属的存在影响了生物处理策略。在生物处理前，迫切需要一种经济地去除重金属的方法。本文研究了金属结合蛋白和金属还原菌等生物配体对脱盐液中重金属的去除作用。该项目是与帝国石油有限公司合作的。目前正在进行的项目的研究工作包括两步方法：(i)研究一种嗜盐酵母汉斯氏德巴酵母（Debaryomyces hansenii）去除碳氢化合物和乳剂，随后（ii）使用嗜盐微藻杜氏盐藻（Dunaliella salina）去除剩余的氮和磷，并生产营养药品，如β -胡萝卜素和清洁水，供精炼厂循环使用。这些营养保健品正在成为新的保健食品部门的宝贵材料。该项目为工业合作伙伴帝国石油有限公司设想的重大利益将是更好地管理污水流，并具有将清洁水回收到炼油厂操作中的强大潜力。由于大量的水**被利用，在炼油工业中水循环可以是一个主要的好处。

Desalting and dewatering of crude oil upstream of the crude distillation unit (CDU) is an important unit operation for the removal of salt and other undesirable components from crude oil. The desalter effluent stream arising from this unit operation contains many contaminants such as hydrocarbon emulsions, heavy metals, salts such as chlorides and carbonates, suspended solids, hydrogen sulfide (H2S), ammonia, and phenolic compounds. Current approaches to desalter effluent treatment include sedimentation to remove sludge and suspended solids, dissolved air flotation to remove oil and/or membrane/reverse osmosis to remove metals.**However these techniques are inefficient and expensive. The presence of heavy metals in the desalter effluent impacts biological treatment strategies. An approach is urgently needed which can economically remove the heavy metals before biological treatment. In this proposal, the removal of heavy metals is investigated from desalter streams by using specific biological ligands such as metal binding proteins and metal reducing bacteria. This project is in collaboration with Imperial Oil Limited. The current research efforts in the ongoing project involve a two step approach: (i) investigation of a halophilic yeast Debaryomyces hansenii for the removal of hydrocarbons and emulsions and subsequently (ii) the use of halophilic micro-algae Dunaliella salina to remove the remaining nitrogen and phosphorus and produce nutraceuticals such as beta-carotene and clean water for recycle to the refinery. These nutraceuticals are emerging as valuable materials in a new health food sector.The significant benefit envisioned for the industrial partner in this project, Imperial Oil Limited, will be better management of effluent streams with strong potential for clean water recycle into refinery operations. Water recycling in the refinery industry can be a major benefit due to the large volumes of water**utilized.