It's time to reuse that damn wastewater!

Water scarcity is everywhere. Solutions exist, but they also come with additional challenges.

Feel lost? No worries, we've got your back with this week's guest of the "(don't) Waste Water" podcast.

Christos Charisiadis is R&D Engineer at Lenntech. He studied as a civil engineer, with specialization in hydraulic construction. He also owns two masters in water and wastewater treatment, and is passionate about desalination, wastewater reuse, brine treatment and above all, innovative approaches - as you'll discover.

dww.show

Hi, Christos, welcome to the show. How is the weather today in the Netherlands?

Christos Charisiadis

Strangely great! The good thing is, that for the last three months during the quarantine, the weather has been great. Lots of sunshine! That keeps us going during these challenging times.

dww.show

Let's start with a short word on you. You are working as an R&D engineer at Lenntech, but your history with water is starting a bit before. Can you guide us through your journey from hydrology to wastewater treatment?

Christos Charisiadis

I am a civil engineer with specialization in hydraulic construction, but I was always fascinated by water and wastewater treatment. For this reason, I have done two masters on that topic. And as I delved more and more, I realized that I have a great interest in desalination. So by the time of my master in Germany, I came in contact with some brilliant professors who had this broad Idea of brine treatment, which was the first time I heard of. From that point on it was a never ending trip to innovation! Especially when it comes to treating high salinity brines, and interesting wastewaters.

dww.show

Today you're working at Lenntech. If you were to pitch Lenntech, assuming I don't know the company, how would you present it to me?

Christos Charisiadis

Lenntech is a 27 years old OEM company, that has a certain experience in tertiary water treatment. We have a strong worldwide presence. Our specialization is to deal with hard cases.

dww.show

You mentioned the worldwide presence, I've seen that you are active in 140 countries and you have three offices in the Netherlands, US and Dubai. So how are you organized?

Christos Charisiadis

Our headquarters (design and manufacturing) are here in the Netherlands. And we have two satellite offices in the US and Dubai. Here in Delft in the Netherlands we are two kilometers away from TU Delft (the university) which we cooperate tightly with, especially for European projects. We have around 50 people from 18 different nationalities, and we speak 20 different languages. So not only do we have the know how to deal with a lot (if not all) of the water treatment cases, we can also do it in every possible language.

dww.show

What about the secret sauce of Lenntech? You mentioned you're at home when it's demanding to the water. So what's exactly the field of expertise of the company. What is your playground?

Christos Charisiadis

The secret sauce is that… there is no sauce. Just kidding. We have dedicated people in the company that know what they're doing. We're very interested in optimization, innovation. Every day we come up with something new in the water treatment market. We are cooperating with others, suppliers or technology providers. So we are not, let's say married to anybody, we are cooperating with the best case scenario in order to help our clients. Lenntech is in the eye of the hurricane when it comes to innovation and coming up with creative and reliable solutions. And this along with the love and care we put in our projects, makes us special.

dww.show

You've mentioned that it's many people that work at Lenntech and make it special. But I guess you're one of these special people! So can you maybe tell us a bit more, what are your tasks as an R&D engineer?

Christos Charisiadis

I would say I am more on the "B" side than on the "R". I'm more on the business development side. The main point of R&D is to search for new solutions. My main focus in the company has to do with brine treatment technologies and Zero Liquid Discharge (ZLD). For these reasons - and for the last two and a half years that I've been working with Lenntech - I have been in contact with more than 20 technologies all around the world, trying to develop the commercial opportunities, talking with suppliers, clients, coordinating, perhaps some time helping out with the process design.

dww.show

So is it business development with a technical touch, or technical development with a business touch?

Christos Charisiadis

It's a bit of both! This is what makes it interesting for me. I'm not purely sitting in front of a screen, and on the other end, I'm neither spending a whole day talking on the phone. That's like a best of the two worlds.

dww.show

You mentioned some projects, which were good examples. Can you maybe give us one example of what you've been doing over the last year? If you had to choose just one (I know this is a difficult one).

Christos Charisiadis

I would like to mention a lot! But one that I really love, is the treatment of a very complex 10-12% Total Dissolved Solids (TDS) Brine, which had absolutely everything inside. Salts, heavy metals, a bit of organics... This was honestly a real head breaker for me until we found a liquid-to-liquid water extraction method. We have been working with the client and the technology supplier for the last one and a half year.

dww.show

So when you're doing that, you're really partnering with the supplier in order to bring everybody, all the right brains on the table, and find a solution.

Christos Charisiadis

Exactly. As I mentioned, Lenntech is an OEM system manufacturer. So we are always working together with technology suppliers under their guidance, and the help of our experienced process and product engineers to get these solutions out in the market.

dww.show

And in those cases, does it start with a pilot, and then you grow from there?

Christos Charisiadis

Usually - and I can't mention this enough - I would like to invite you to our lab facilities. Lenntech has an extensive lab in our headquarters in Delft, equipped with every possible technology that you can think of. This allows us to demonstrate to the clients the potential of each one of them, along with their combinations. So this is how it starts.

dww.show

So it starts with an Idea, gets checked in the lab and developed in the pilots, and then it goes to a full scale. And then I guess it's the beauty of industrial markets: everybody's happy. Actually. I think we get to know you a bit better and we have an overview of what your company does.

I would like now to dig a bit deeper into those topics of wastewater reuse and zero- or minimum liquid discharge. You're going to share us in some minutes, your view on the difference between both. Actually when preparing for the discussion, I found out that the first evidence in the history of wastewater reuse can be found in the ancient Rome, because there they were using the water in the Spas and then reusing the water to flush the toilets. But it seems to me like there is a span of almost 2000 years where we kind of forgot about that and said, well, reuse is not really a thing. And it sounds to be back recently. So what do you think: how widespread is reuse today in our industry?

Christos Charisiadis

Wastewater ReUse isn't - exactly as you said - a new topic in the water treatment history. In the last decades it has been used a lot from Israel to other countries in the Middle-East. Europe and the rest of the world is starting to catch up, I guess, due to the ongoing water stress and the climate challenge.

We are rediscovering what should have been applied for the last 20 years.

dww.show

So water stress is the driver?

Christos Charisiadis

Water stress, mainly. But also the environmental effects of wastewater. You see now what's happening in China and India, with the treatment of wastewater. Another driver is the very harsh regulations, which we were reinforced in Europe as well for the last decades, and I hope they will continue doing so. Wastewater reuse also has been a very sensitive topic for me. I come from a South European semi-arid country (Greece). Spain, Italy, Portugal, the South areas of France... All these areas, suffer more or less from the same things (water scarcity, climate change).

dww.show

Could this be solved with desalination or wastewater reuse?

Christos Charisiadis

The thing is that wastewater reuse though, is an easier solution to these kinds of challenges, because you already have a water, that you would throw away anyways. If you were to do that, you would essentially through away a very valuable resource, or at best drive it to a very expensive wastewater treatment plant.

dww.show

So what's the solution?

Christos Charisiadis

The solution here is, instead of mixing every wastewater that could be difficult to treat because of loads or pollutants into very expensive wastewater treatment plants, to separate these and have on-site treatments supported by the legislation of each country. This would take care of this problem bit by bit, bringing water back to the industry, getting water back to the households. You have the examples of Hong Kong and Cape Town which mix a certain percentage of their treated wastewater with fresh water to go to the tap. Although this could sound disgusting to many listeners, I think this is essentially where we're going.

dww.show

It's a bit the story of the NeWater in Singapore. If you're really lacking water, you need to have this closed loop. You've mentioned something really interesting with this separation of the flows. In the Urban area, we see there's the wastewater and then the rainwater, which sometimes are separated, but in the industries, how is it? Is it like every batch has his separate flow and you might be able to treat them locally or is everything brought together in a plant which might lead to efficiency losses?

Christos Charisiadis

One of the first questions I ask our clients, when they want to treat a stream, is the following: is it the result of one or more processes. Is it a mix? And why is that? Some streams are harder to treat than others.

So it's more economical to treat a hard stream in small scale rather than mix it with other streams and treat them all together.

It goes back to the wastewater treatment plant example I just gave you. Inside the same plant, a lot of times, we have different wastewater streams. We want to treat them if possible separately in order to have an efficient wastewater treatment in your facility.

dww.show

You would have separate streams, as much as possible, trying to treat them with smaller size treatment steps. I guess if you start to do that, membranes will have quite a high role because some of the very concentrated ones will be treated directly through membranes, while other might go through regular biology or specific steps. What would be the typical treatment chain you would see when you are reusing a specific flow?

Christos Charisiadis

Membrane technology has advanced a lot for the last 5 years, more or less. It really got more and more innovations over the last decade. And as we speak, for example there are hollow fiber membranes that can do multiple filtration steps at once. Or you have ceramic membranes, that can take care of extreme wastewater cases. Smaller footprint, smaller CAPEX, smaller OPEX!

dww.show

So what are we waiting, let's reuse that wastewater!

Christos Charisiadis

I strongly believe that every wastewater available can and should be treated and reused. Let's imagine for instance, we are in a household. You have the grey wastewater and you have the black wastewater. Both can be treated, of course the grey wastewater easier than the black. But it should be recovered! We're trying to convince the households to use this wastewater for non-potable usage. But we should also try to convince through regulations, EU or state funding in general, the industries to reuse their water resources and take as least amount of water as possible from the public network.

dww.show

You've mentioned three factors. You've mentioned CAPEX, OPEX and footprint. I guess all of them for sure play a role, but if you had to rank them, how is it today? What would be the first thing you look at? Is it the investment, the operation costs or where to fit it in the plant?

Christos Charisiadis

For me personally, one is influencing the other, but it also depends on the client. Do they have the money to invest straight through? So sometimes the clients are asking for CAPEX, other times people ask for ROI (Return On Investment). So usually, you have to design a system with an ROI or three years or less. And this is a factory straight from the OPEX factor. This is what we are doing, for example, with the Zero Liquid Discharge processes, where we are trying to lower the energy consumptions.

dww.show

Before introducing this ZLD topic, I would have one last question. You know, in the world "wastewater", there is waste. So for everybody, it's like something which you're really dumping away. And it turns out if you're going to reuse and even more, if you're going to zero liquid discharge, that it's no longer really a waste, it becomes a resource. What's your vision on that?

Christos Charisiadis

Definitely there's a lot of potential from industrial and urban wastewater. There's a lot of viable contaminants to be recovered in the form of salts, metals, nutrients. I think there was a very interesting Horizon 2020 project on improving the biogas production from wastewater treatment, in order to cover the energy demands of the plant. You can get a lot of interesting products from your wastewater stream, and if you do a proper market research, you can always find a solution to sell them, ranging for example, from salts for fishing companies to very viable metals that can be used in the industry. The opportunities are there, all you need to do is to have a little bit of creativity and market research. And I think we're getting there step by step.

dww.show

You mentioned, it's an opportunity. Actually, usually opportunities come with challenges. And I guess the biggest challenge when it comes to wastewater reuse lies in the brines because you get brines and you need to treat them. You've written an amazing booklet on this topic. (I really recommend you to read it, it's very interesting!) Maybe you can tell us in a couple of words, what are the brines and what are the challenges which come with the brines?

Christos Charisiadis

The word "brine" is a little bit tricky. When some people mention brine, they're meaning brackish water, while some other people mean concentrates of reverse osmosis. For my understanding when I say "brines", I mean solutions of 6% and up of TDS. Meaning 60,000 mg/L of TDS. So high salinity brines can't be treated from a typical reverse osmosis. This is why a lot of interesting processes have been developed, ranging from ultra-high pressure reverse osmosis to membrane distillation, forward osmosis and other interesting technologies.

dww.show

So those are the technologies that would be used for a zero liquid discharge or a minimum liquid discharge. What would be the way to choose the right treatment from this full array of options?

Christos Charisiadis

Every technology has its pros and cons. Some technologies demand the existence of waste streams or vapor stream in order to become viable. This is the case of the typical MLD or ZLD solution which is the evaporator. In order for this solution to become viable, you need to have some vapor stream that the evaporator can use. Because if you would use an electricity-powered solution instead, you're going to have a problem when it comes to energy consumptions. Every wastewater has its own challenges to overcome. And this is why it is important, that the water market has a lot of solutions. The world would be very, very dull, if there was no solution for every problem!

dww.show

So you have to have a look on the water because the water at the end of the day still decides what you are going to implement. But you also need to consider the environment, because if you have some networks available, for sure, it makes it easier to use some solutions. There's an interesting graph in your paper about the comparison between zero liquid discharge and minimum liquid discharge. Before digging into that, can you just explain us the difference between zero and minimum?

Christos Charisiadis

Sometimes people want high recovery from their wastewater and they're mixing it up with Zero Liquid Discharge. So ZLD is getting no liquid waste out of your process and solids as side products. For this to be done, it's very expensive. It's very expensive to usually get these last drops of water out of the stream.

dww.show

The last 5%? The last 10%?

Christos Charisiadis

I would say, the last 5-10%. Usually, it's very easy to recover 80%. I think this is more or less the MLD level, 80-85%. And in order to get from this point up, you need a lot of efforts in machinery and energy. You have to sit down and ask yourself, do I really need to get up to that point? You have to ask yourself what are your water needs in the plant. What are the legislations you have to follow? What is the environmental impact? According to these, sometimes you don't need to take out all of the water. This 20% recovery of water, for example, can make all the difference when it comes to CAPEX. I have seen systems where these last 20% cost 60% of CAPEX, or the double CAPEX of the whole system.

dww.show

You have 40% of the CapEx to take out up to 80%. And the last step is taking 60%. So three times more expensive.

Christos Charisiadis

Not only more expensive CAPEX wise, but it can also be three times up when it comes to OPEX. There are of course new innovative technologies we are using, as I mentioned, for example, the liquid-to-liquid water extraction. But they're definitely more expensive than a minimum liquid discharge technology. It goes like that in the water market, unless someone is really pressed from the legislation, or is really pressed from their water needs, they won't go there. ZLD market is a very niche market at that point: I think we are moving across to more and more cases year by year, as water stress grows, but unless there is an immediate need to recover all the water, you don't need to. You can save a lot of money and a lot of effort, just by going to 80-85%. For example, we have membrane processes that can concentrate the sea water up to 20% and that gives an almost 85% recovery. You don't need to go any higher unless you do need these last drops of water or take out the salt products.

dww.show

ZLD is a niche as such, but how widespread is MLD? Is it like one industry which would not be reusing would be looked at like "hey, you're just wasting water!" or is it still something where they need to be proactive in some countries? What's the market's maturity towards minimum liquid discharge?

Christos Charisiadis

The way I'd see it from my interaction with the industry for the last, let's say four years, you might think that the water recover maturity is not really there yet. You don't have legislation, although it's getting stricter, you can find a lot of cases where it is still a bit loose. Unless there is someone directly on top of you, breathing on your neck to do it, nobody will take care of it.

And what pains me is, that the areas that need it the most, never think of it.

I don't know if you saw recently this video from national geographic, about the water resources in Greece and the need for desalination. Coming from that area, I can really say, Greece doesn't take care of water resources. And if we don't do something about that, there's going to be a very immediate danger in the next 5-10 years,

dww.show

There was also another article that you shared, it was about the cost of water produced with desalination and the cost of water coming from wastewater reuse. And it turned out that wastewater reuse is much cheaper, but there's a problem with the perception because people are not really ready for that.

Christos Charisiadis

What I see right now, is that some hotel resorts are starting to do it using classical MBR or another wastewater treatment. The general public is not really informed, or really psychologically ready, for this wide use of recycled wastewater.

But it's not the large public which needs to change its mind, because it's not the one not who is mainly contributing to water usage.

I think you know that the main contributor to water spending is agriculture in every country ranging from 40 to 60%, then you have industry. And then perhaps the last let's say places you have usages are households. We have mentioned wastewater reuse. We have mentioned desalination, but really the first step that we must take is improve water resources management.

dww.show

Wastewater reuse should be used in agriculture, and then also in the industries, which are very demanding in water, such as power, coal to chemical... Are these the ones which need to be educated?

Christos Charisiadis

Production of Ultrapure Water for the semiconductor industry is another example... We have a lot of interesting cases, we have a lot of industries that need a lot of water, and very good water quality. We have to make them understand - or we have to force them with legislation – that they shall not use the public network, but rather recover and reuse the water they already have. I've always said that one of the model or examples when it comes to water management and water reuse is Israel. We have seen the efforts they have put in the last decades or the innovations they have been putting in the markets, more and more.

dww.show

If I just round up this part, I would say that, and you tell me if you agree, none of that is new. Reuse is a topic, which is on the table for decades, as you said. We have technologies in place. We have possibilities and we have also opportunities to use them to get higher value out of it. But still there's a long way to go in many countries and maybe it needs some support from the regulation and it needs some push in some areas of use.

Christos Charisiadis

Exactly my point, thank you for summarizing up!

RAPID FIRE QUESTIONS

dww.show

So first question: what is the most exciting project you've been working on?

Christos Charisiadis

I think we have already talked about this. Treating this extremely high TDS brine which has everything in it. It has been a headbreaker, but solving this puzzle has given me the opportunity to, put a small brick in the revolution of a specific market.

dww.show

What's your favorite part in your job?

Christos Charisiadis

Searching, searching, and trying to solve a riddle. It's a little bit like the back end work. So as we said, every case is unique. Every case has its own challenges to overcome, and the process of imagining this process, and solving its problems day by day, because no solution is absolutely perfect, is really fascinating. There are problems coming up everyday, and then the way you find solutions for each one of them is very tricky. It requires a lot of technical knowledge, people knowledge, and management capabilities. And I think this is what attracts me most in my daily routine

dww.show

What is the trend to watch out for in the water industry?

Christos Charisiadis

Extreme wastewater cases are becoming more and more of a norm in the markets. We should always look for niche needs and try to push into these areas, especially the ones that have the possibility of recovery or viable contaminants.

dww.show

What is the thing you care the most when you design a new product or a new process?

Christos Charisiadis

It has to run smoothly. And what's CAPEX, OPEX, all this kind of things, when you design a process it's quite tricky. It requires a lot of inputs from a lot of people, but in the end, I would just like to make it work despite some of the problems arising from ongoing communication. And I'm more than happy when finally that system operates smoothly on the field.

dww.show

So what you care the most is that it runs smoothly. What is the thing you care the less? If there's one.

Christos Charisiadis

I don't think there's a thing that you should not care about in the system. All its facets, all its angles should be accommodated according to the needs of the case and the clients. From CAPEX, OPEX, Footprint, availability of maintenance spaces, everything has to be taken care of. And, it's our job as water industry professionals to look at every possible detail. And I'll tell you what, I've seen a lot of people not caring about the danger factors. This is what happens when they care about the system, but they don't see any potential dangers coming out of it. As a civil engineer, I have always been used to accommodate an extra danger analysis in my system design. I have mentioned this to my directors and to my clients to accomodate for. As a professional, I have to take care of every angle, even if there are some things that I really don't like. Documentation is one - nobody likes documentation, but still we have to do it. Someone has to take care of it!

dww.show

Do you have sources that you would recommend to keep up with the water and waste water market trends?

Christos Charisiadis

So you have some water magazines...

dww.show

Which one do you prefer? What's your favorite one?

Christos Charisiadis

The IWA magazine, as well as GWI. I can't stress enough though, the needs to read the scientific journals. Never underestimate the power of R&D. You have to think creatively. And for us, that would like to see the bigger picture in the water markets, in order to do this, we have to get a lot of incoming information. Then you start to complete the puzzle bit by bit in order to give yourself a more clear picture of what is going on. And that allows for your company to move ahead in the markets with commercial opportunities. Just to self advertise a bit, this is what Lenntech does, this is one of our main strong points that the company invests a lot, puts a lot of efforts and time into its R&D department in order to provide innovative and efficient solutions to whatever problem that may come up.

dww.show

Don't be shy about it! I mean, it's important to be proud of what you do and what your company does, because that's the way to be sure that you do something right. You've been an amazing guest for this podcast. Thanks for that. Who do you have someone that you would recommend that we should definitely invite as soon as possible?

Christos Charisiadis

I think the most interesting speaker you can have is Ravid Levy. He has got more than 15 years in the water industry, currently based in Israel, and he works currently as a consultant, connecting new technologies to the water markets around the world. If there is someone who knows about R&D, product design, commercialization of advanced water and wastewater technologies, he is the person to talk to.

dww.show

So I make sure that we extend (a new!) Invitation to him. Thank you for the advice to conclude the episode, where can the auditors look for you? You personally, your company, where would you like to link them?

Christos Charisiadis

Lenntech has a very strong internet presence through its very informative site. I think we are entitled to the title of "Water Wikipedia". Most of the times with every request, we come in the first results. If you would like to contact me personally, all you have to do is to send an email to [email protected]. My email is also on the booklet that you suggested, so I will be more than happy to accommodate for whatever demand rises from this interview!

dww.show

And that's a perfect conclusion, Christos. Thanks for being with us today. How would you say goodbye in Greek?

Christos Charisiadis

αντιο σα?!

dww.show

I'm glad I don't have to say it, because my accent would be terrible, but... αντιο σα?!

Christos Charisiadis

Thank you for having me!

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