As the EPA conducts fact-finding surveys in the metal finishing community regarding PFAS contamination, wastewater treatment is a growing concern for finishing operations. 在本期的 产品完成’s On the Line interview column, we’re digging into trends in wastewater management. 罗宾的交易, product manager and wastewater treatment specialist with Hubbard-Hall, recently took some time out of her busy schedule to sit down with PF 并讨论这个领域的最新进展.

PF: What emerging technologies or trends are influencing or changing the way we approach the management of wastewater?

There are so many things going on right now in wastewater that I think some things can get lost. The biggest topic — the most talked about subject in metal finishing wastewater treatment right now — is PFAS. 当人们说到PFAS, they don’t really realize this is a term for over 9,000种不同的化合物.

And so, we are talking about how we remove that from our wastewater. 但在我们讨论如何移除它之前, we’ve got to understand where it comes from Which compounds are in our facilities? 他们是带着零件还是原材料进来的? 他们是通过化学反应进来的吗?

Then we got to identify which components we were looking at and how to remove them. 这就是移除的新趋势, of activated carbon have been successful for some of the forms of PFAS. Electrocoagulation has been successful for some, and advanced oxidation has been successful for some.

所以，现在这是一个巨大的焦点.

但同时, we’re also seeing many people focusing on how they can get to a zero-liquid discharge state with their wastewater systems. How do they start reclaiming and recycling their wastewater — especially as we go further west, where water scarcity has become such a huge topic in places like California, 华盛顿州, 俄勒冈州, 德州, 和新墨西哥州, Their focus is more on reclamation and how to reuse. So, trends around [recycling and reuse of wastewater] involve things like ion exchange, 正向渗透(不只是反渗透), and evaporative technologies with condensation collection systems on on top of it.

There are a lot of things going on when we talk about emerging trends — we can go down so many different avenues.

PF: PFAS is such a big topic for finishing operations right now — do you mind talking a bit more about that area of concern?

这个问题可以追溯到90年代末, 21世纪初, when the EPA and OSHA got together and said to protect workers from [exposure to] hexavalent chrome plating, we should use a PFAS compound as a fume suppressant. 到2010-2015年左右, a lot of players had already moved away from using those compounds, but there are still residual traces of it — in their tanks and their walls and floors. And it leeches out over time into the wastewater. So, there’s only one way that has been tested and proven effective to destroy these PFAS forever chemicals, 这就是高级氧化.

高级氧化使用过氧化物和铁, or iron and UV radiation to speed up at the decay of the products. 但并不是对所有人都有效. It only works on a handful —and it can be pretty expensive.

So, 如果我们不能用这种方法摧毁化合物, what other ways can we use it to remove it from our water? We can do things like activated carbon filtration units, 静电碳过滤, where the carbon (which has a massive surface area, will absorb and hold on to the PFAS — it doesn’t destroy it, 但它确实把它从水中带走了. 还有电凝, where we use electricity and iron as a sacrificial component to filter out and coagulate and precipitate out [PFAS]. So those are a couple of the things that people are looking at.

There’s also a bacterial treatment — where bacteria are used to consume the PFAS as a food source — that’s being investigated.

PF: Can you talk a bit about some of the biggest challenges you see for finishing operations when it comes to navigating some of these issues?

Metal finishers are not in the business of treating wastewater. 这并不是一个玩家想要做的. 这不是一家油漆店的初衷. 他们着手为消费者完成产品. Wastewater is kind of pushed to the background.

With other industries like mining and the oil and gas industry, people look at those industries and the environmental impact, so there is a lot of education for wastewater operators.

I don’t think we educate ourselves enough in the metal finishing industry. I would love to see us have more education about what chemistries we use how they’re impacted, and how we can become better at wastewater treatment. I think that probably the biggest challenge is the education component. Pulling [the topic of] wastewater from the background and putting it front and center, 我认为这对我们的行业至关重要.

也, 当我们谈到生产一个零件的成本时, 我们谈到了化学品成本和劳动力成本, but I never really hear anyone talk about the water cost. 生产一辆汽车需要多少水? 40,000 gallons of water to produce one automobile. 我们不会停止制造汽车. 那么，我们如何节约用水呢? How can we successfully treat that water that becomes waste and reuse it? I think those are some of the challenges that, as an industry, we need to be talking about more.