Having worked with biofilms since the 1970s, I know that they are ubiquitous in nature, of great value in water technology, and scientifically fascinating. Biofilms are naturally able to remove BOD, transform N, generate methane, and biodegrade micropollutants. What I also discovered is that biofilms can do a lot more for us in terms of providing environmental services if we give them a bit of help. Here, I explore how we can use active substrata to enable our biofilm partners to provide particularly challenging environmental services. In particular, I delve into three examples in which an active substratum makes it possible for a biofilm to accomplish a task that otherwise seems impossible. The first example is the delivery of hydrogen gas (H₂) as an electron donor to drive the reduction and detoxification of the rising number of oxidized contaminant: e.g., perchlorate, selenate, chromate, chlorinated solvents, and more. The active substratum is a gas-transfer membrane that delivers H₂ directly to the biofilm in a membrane biofilm reactor (MBfR), which makes it possible to deliver a low-solubility gaseous substrate with 100% efficiency. The second example is the biofilm anode of a microbial electrochemical cell (MxC). Here, the anode is the electron acceptor for anode-respiring bacteria, which “liberate” electrons from organic compounds and send them ultimately to a cathode, where we can harvest valuable products or services. The anode’s potential is a sensitive tool for managing the microbial ecology and reaction kinetics of the biofilm anode. The third example is intimately coupled photobiocatalysis (ICPB), in which we use photocatalysis to enable the biodegradation of intrinsically recalcitrant organic pollutants. Photocatalysis transforms the recalcitrant organics just enough so that the products are rapidly biodegradable substrates for bacteria in a nearby biofilm. The macroporous substratum, which houses the photocatalyst on its exterior, actively provides donor substrate and protects the biofilm from UV light and free radicals in its interior. These three well-developed topics illustrate how and why an active substratum expands the scope of what biofilms can do to enhance water sustainability.

自从1970年代开始与生物膜合作以来，我知道它们在自然界无处不在，在水技术方面具有重要价值，并且在科学上引人入胜。生物膜自然能够去除BOD，转化N，产生甲烷并生物降解微污染物。我还发现，如果我们向生物膜提供一些帮助，它们可以在提供环境服务方面为我们做更多的事情。在这里，我探讨了如何利用活动基质来使我们的生物膜合作伙伴提供特别具有挑战性的环境服务。特别是，我研究了三个示例，在这些示例中，活动的基质使生物膜可以完成原本似乎不可能的任务。第一个示例是氢气（H ₂）作为电子给体，以驱动氧化污染物的数量增加和减少，例如高氯酸盐，硒酸盐，铬酸盐，氯化溶剂等。活性基质是传递H ₂的气体转移膜直接在膜生物膜反应器（MBfR）中将生物膜转移到生物膜上，这使得以100％的效率输送低溶解度的气态底物成为可能。第二个示例是微生物电化学电池（MxC）的生物膜阳极。在这里，阳极是呼吸阳极细菌的电子受体，该细菌从有机化合物中“释放”电子并将其最终发送到阴极，在这里我们可以收获有价值的产品或服务。阳极的电位是用于管理微生物膜和生物膜阳极反应动力学的灵敏工具。第三个示例是紧密耦合光生物催化（ICPB），其中我们使用光催化来实现内在难降解有机污染物的生物降解。光催化作用足以使难分解的有机物发生转化，从而使产品成为附近生物膜中细菌的可快速生物降解的底物。大孔基质在其外部装有光催化剂，可主动提供供体基质并保护生物膜免受其内部的紫外线和自由基的侵害。这三个发达的主题说明了活跃的基质如何以及为何扩展生物膜可以做什么以增强水的可持续性的范围。