Institute for Sanitary Engineering and Waste Management, Leibniz University Hannover, Appelstr. 9a, D-30167 Hannover, Germany.
Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria St., Toronto Ontario M5B 2K3, Canada.
Chemosphere. 2018 Dec;212:898-914. doi: 10.1016/j.chemosphere.2018.08.145. Epub 2018 Aug 30.
On-site flowback treatment systems are typically rated and selected based on three fundamental categories: satisfying customer needs (e.g. meeting effluent quality, capacity, delivery time and time required to reach stable and steady effluent quality), common features comparison (e.g. treatment costs, stability of operation, scalability, logistics, and maintenance frequency) and through substantial product differentiation such as better service condition, overcoming current market limitations (e.g. fouling, salinity limit), and having lower environmental footprints and emissions. For treatment of flowback, multiple on-site treatment systems are available for primary separation (i.e. reducing TSS concentrations and particle size below 25 μm for disposal), secondary separation (i.e. removing TSS, iron and main scaling ions, and reducing particle size up to 5 μm for reuse), or tertiary treatment (i.e. reducing TDS concentration in the permeate/distillate to below 500 mg/L) for recycling or discharge. Depending on geographic features, frac-fluid characteristics, and regulatory aspects, operators may choose disposal or reuse of flowback water. Among these approaches, desalination is the least utilized option while in the majority of cases on-site basic separation is selected which can result in savings up to $306,800 per well. Compared to desalination systems, basic separation systems (e.g. electrocoagulation, dissolved air floatation) have higher treatment capacity (159-4133 m/d) and specific water treatment production per occupied space (8.9-58.8 m/m), lower treatment costs ($2.90 to $13.30 per m) and energy demand, and finally generate less waste owing to their high recovery of 98-99.5%, which reduces both operator costs and environmental burdens.
满足客户需求（例如满足废水质量、处理能力、交付时间和达到稳定废水质量所需的时间）、常见特征比较（例如处理成本、操作稳定性、可扩展性、物流和维护频率）以及通过实质性的产品差异化，例如更好的服务条件、克服当前市场限制（例如结垢、盐度限制）以及具有更低的环境足迹和排放。对于回流处理，有多种现场处理系统可用于初步分离（即降低 TSS 浓度和粒径至 25μm 以下，以便处理）、二次分离（即去除 TSS、铁和主要结垢离子，并将粒径减小至 5μm 以下，以便再利用）或三级处理（即降低透过液/馏出液中的 TDS 浓度至 500mg/L 以下，以进行回收或排放）。根据地理位置、压裂液特性和监管方面的因素，操作人员可能会选择处理或再利用回流水。在这些方法中，脱盐是使用最少的方法，而在大多数情况下，选择现场基本分离可节省每口井高达 306800 美元的成本。与脱盐系统相比，基本分离系统（例如电絮凝、溶解空气浮选）具有更高的处理能力（159-4133m/d）和每占用空间的特定水产量（8.9-58.8m/m），更低的处理成本（每立方米 2.90 至 13.30 美元）和能源需求，最后由于其 98-99.5%的高回收率，产生的废物更少，从而降低了操作人员的成本和环境负担。
