Water companies in the United Kingdom are currently facing unprecedented tightening of phosphorus discharge consents, which will only become stricter in the near future. Historically, the most widely applied method of phosphorus removal has been chemical precipitation through the addition of iron or aluminium salts. Although more sustainable options, such as biological processes, are already being implemented at key sites, data shows that chemical removal is likely to remain an integral part of wastewater treatment—whether as the main method in small or problematic works or as a trim for meeting consents below 1 mg/L, not achievable through biological removal alone. All sewage treatment providers in the United Kingdom have developed asset standards (internal design and operation guidelines) for the design and management of chemical precipitation at existing works. However, the approach has not been consistent throughout the sector, with wide variations of criteria, brackets and rules of thumb. This paper collates and compares these approaches, looking at asset standards from most of the water companies in the United Kingdom. The methods stated in these standards have been applied for the sizing of chemical phosphorus removal on four simulated sites, to meet theoretical consents based upon the future discharge requirements set by the Environment Agency under the Water Industry National Environment Programme.

中文翻译：

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英国废水行业化学除磷的不同方法

英国的自来水公司目前面临前所未有的磷排放许可收紧，而且在不久的将来只会变得更加严格。历史上，应用最广泛的除磷方法是通过添加铁盐或铝盐进行化学沉淀。尽管更可持续的选择，例如生物工艺，已经在关键地点实施，但数据显示，化学去除很可能仍然是废水处理的一个组成部分——无论是作为小型或有问题的工程的主要方法，还是作为会议的补充同意低于 1 mg/L，仅通过生物去除无法实现。英国所有污水处理提供商都制定了现有工厂化学沉淀设计和管理的资产标准（内部设计和操作指南）。然而，整个行业的方法并不一致，标准、括号和经验规则存在很大差异。本文整理并比较了这些方法，研究了英国大多数自来水公司的资产标准。这些标准中规定的方法已应用于四个模拟场地的化学除磷规模，以满足基于环境局根据水工业国家环境计划制定的未来排放要求的理论同意。