Changes and Packing (Reflections from El Paso, Post 3)

Things got a bit hectic during the last few weeks in Honduras and it has taken me a while to get situated at home again. I do want to take the time to finish up on our activities, so this is the third of at least three that will summarize what we did in September and what we are planning to do in the future.

===============================================

We turned off the desalination system on 8 September and kept the evaporation system running until 9 September. Then we started packing. To be honest, it was kind of sad. We have worked with a great bunch of people and got to work in a wonderful country. This post will show the packing process, how the site has changed over the last few months, and will include my attempt at showing the joy that a fun team can bring to life.

The field where we put the PV panels was originally covered with trash and many plants had been there, but the UPi crew did a lot of work to make the site usable for a pilot. During the last few weeks of operation, we noticed that a lot of plants had been growing between the PV panels and along the walls. As we started removing panels, the degree of growth became much more apparent. Plants had intertwined themselves around our wiring, making removal an interesting task. I thought it would be fun to show how things looked during the course of the last few months. Disclaimer: I live (and am from) the desert. Green things are somewhat abnormal - even after two months in a very green place.

[Pictures came from multiple sources including Clara Borrego, Victoria Amador, and Victor Zepeda]

View from the front of the field.
The first picture shows how barren the land was (after the UPi crew had cleaned it)
The middle picture shows how the field looked with the panels installed towards the beginning of the pilot
The final picture shows the field after we removed the panels

View from the back of the field.
(LOOK AT ALL THE PLANTS!)

So, back to the packing process. One lesson learned from shipping the system to Honduras was that we wanted to protect the PV panels better. We thought that we had secured the panels very well for shipment, but we hadn't built any structure to hold them in place (other than ratchet straps and pallets). So, we decided to build boxes to provide more structural support (we hope!). The next parts involved packing from the back of the container to the front. It got a little tight towards the end.

Clara and Mr. Rusbel devised a plan for the boxes using the pallets we used to ship from El Paso.
We had to build the bases first, then load them into the container.

For some reason, using power tools using solar power always made me smile.
(I'm not good with saws, thankfully Clara and Rusbel are)

The completed boxes & the straps
Each box had L-brackets to secure the sides to each other, the base, and the the top. We used ratchet straps to secure everything to the floor of the container.

The next step involved taking the array apart and dismantling the desalination system. Similar to when we packed the system in El Paso, we had as many people as possible to save our backs and make the work go faster. But, in Tegucigalpa, UPi brought a grill and made delicious tacos for all! 

Each of the blocks weighs about 25 pounds. We had over a hundred of these to remove, stack, then load into the container.

Clara is always smiling.

I didn't realize we'd have such a perfect stack of blocks!

Jonathan Eveline helped get some of the L-braces onto the PV panel boxes.

It takes a group of us to get everything loaded. (Sorry for my bad picture skills, Victoria!) 

The final pieces. By this time, we were having to crawl over things and squeeze through small spaces.

The container was shipped to UPi for storage until we can find funding for the next adventure. Let me know if you'd like to be part of it. We will need partners, funding, and possibly volunteers.

The desalination container gets some rest at UPi. (what a view!)
[Photo credit: Victoria Amador; great shot, thank you!]

What a fun team. The UPi-UTEP crew will work together and have fun again. Thank you to all that made this possible.

...Stay Tuned

Hindsight is 20/20: Some preliminary conclusions (Reflections from El Paso, Post 2)

Things got a bit hectic during the last few weeks in Honduras and it has taken me a while to get situated at home again. I do want to take the time to finish up on our activities, so this is the second of at least three that will summarize what we did in September and what we are planning to do in the future.

===============================================

After having a few weeks to think about what we have learned, I keep thinking "If I only did this..." or "If I just would have started with..." or many other things that are only obvious after time has passed and one has learned from experience, mistakes, and observations. This post will be my way of organizing what we learned from the pilot from a technical point of view. This will be a long post, but I will put some pictures here and there to balance the text.

It is probably helpful to review what our initial objectives were for our pilot demonstration in Tegucigalpa. A few months ago, I summarized how we were using ZDD to desalinate brackish water using energy from the sun. We received funding from USAID to:

• Demonstrate that high efficiency and zero liquid discharge are possible using ZDD powered by renewable energy
• Transfer knowledge to our partners at UPi
• Provide training for Honduras farmers about water quality and desalination technology (including ZDD, of course!)
• Assess the commercial potential for ZDD in Honduras

Just in case you forgot - Here's our pilot site, located at the East end of Morazán Blvd
The PV panels were on the ground in the left. The desalination equipment is in the container in the middle of the picture. The salt recovery and enhanced evaporation system was behind the wall with the interesting art on the right of the picture.

In addition to these general objectives, we were also produce 8,000 liters per day of irrigation water and 250 liters per day of drinking water with certain water quality parameters that were set by the Desal Prize judges. The drinking water requirements were relatively simple, in that the salinity had to contain no more than 600 parts per million of dissolved salts (and meet other World Health Organization water quality requirements). Most reverse osmosis and some nanofiltration membranes can meet these requirements. The irrigation water quality requirements were more challenging. The salinity requirement was slightly lower (no more than 550 parts per million of dissolved salts), but other requirements included a sodium absorption ratio less than 3 (this requirement generally ensures better water infiltration into the soil), a calcium to magnesium ratio greater than 1, pH less than 8, and boron no higher than 0.5 parts per million. [If you would like to learn more about how water quality can affect soil quality and crop health, here are some resources from Texas A&M, Colorado State University, and North Carolina State University.] 

Relationship between SAR and Conductivity.
High SAR (high sodium relative to calcium and magnesium) generally reduces infiltration, however it depends also on the salinity (measured using conductivity) also. Some groundwater may have the same SAR, but the one with higher conductivity is more acceptable for irrigation (For more info: Montana State University). 

Most reverse osmosis membranes produce very high quality water from a salinity perspective, however, because the membranes are very good at rejecting large ions and large dissolved species, the concentration of calcium and magnesium in the product water is very low. This means that the water is generally unacceptable for irrigation without adding some minerals back to the water. Our team usually uses a blend of "loose" reverse osmosis and nanofiltration membranes to achieve suitable water quality. The number and orientation of membranes is chosen based on the amount of silica in the water. All of the waste stream from the RO/NF is fed to another system, called EDM, that removes some of the species that limit desalination efficiency using RO or NF alone (read more here). However, EDM does not remove uncharged species like silica, so the concentration will build up between the RO/NF and EDM systems unless the silica has another place to go. Using loose membranes allows us to have the silica pass into the product water. However, there is a balance: as more silica is allowed to pass into the product water, more of other dissolved species also pass into the product water. This means that the product (irrigation water) will have higher salinity. This means we balance the product water quality and silica concentration. If the silica (and/or other sparingly soluble species) reach levels above saturation, they will precipitate on the RO/NF membranes. Sometimes the precipitated salts (sometimes called "scale") can be removed with a chemical cleaning. Sometimes the precipitation is permanent and reduces the membrane performance.

Hindsight lesson #1: Bring more field testing kits and monitor silica more often. We knew silica in the brackish water had the potential to be problematic. However, previous pilot experience had led me to think I could monitor things well enough without having a full analytical laboratory. I. Was. Wrong. We scaled up the first set of membranes permanently, mostly because we weren't adding antiscalant, which mitigates scale formation in the membranes (we added checking on the pump to our regular monitoring to make sure this didn't happen again). We loaded new membranes and we thought they were doing well. But, as it turns out we scaled them up again. I need some more time to do some calculations, but the RO/NF membrane combination seemed to remove more silica than expected, which led to more silica in the RO/NF loop. We ended up installing a bleed line to ensure the silica stayed below a safe concentration. However, the scale was permanent and affected our production. We did a cleaning, but it seemed to affect the salt rejection, so our product water quality wasn't as great. Had we started with the bleed, we probably would never have had the silica problem in the system (good old hindsight...).

Lesson Learned: Measure silica regularly (and check antiscalant addition)

Hindsight Lesson #2: Use acid for pre-treatment of the brackish groundwater (i.e. trust  intuition and past experience). The Desal Prize judging rules penalized teams for using chemicals, like acid, as part of the desalination process. So, we decided to try to operate without acid, even though the alkalinity present in the Los Almendros well was higher than any other groundwater the team had ever worked with in past pilot tests (I wrote about this here). Alkalinity present in the RO/NF concentrate ends up in the EDM's Mixed Na stream at a much higher concentration. Because the compounds formed (mostly sodium bicarbonate, but also some sodium carbonate) could eventually be supersaturated and precipitate, the stream is eventually diluted with a very low salinity water. Finding the setpoint for dilutions without an alkalinity test kit involves trial and error, and some indirect measurements. We operated for the first few weeks this way, but eventually decided to install an acid feed line on the brackish feed. Had we done this from the beginning, this could have been incorporated into the automatic controls. I chose not to do this partially for budgetary reasons, but also because I really wanted to see how the system would perform without acid. In previous pilots I have been able to find the appropriate setpoint without needing to do a lot of field tests, however, field tests ended up being necessary. We thought we would have access to a laboratory with alkalinity test capabilities for the pilot, so we didn't bring reagents with us. After receiving a test kit that was sent from UTEP, we were able to monitor alkalinity in the RO/NF and EDM systems and were able to get mostly stable operation. While the process was not smooth, we did find a pH setpoint that seemed to work for both the RO/NF and EDM systems. Thankfully, we had UPi students available to help with the field tests.

Monitoring Alkalinity.
Top Left: Using the trial & error method involves testing various concentrations in the Mixed Na stream. If the concentration is too high, scale forms in the Mixed Na compartments. We could confirm that the scale was carbonate-based by adding acid and seeing if it bubbled.
Bottom Left: Indirect measurements involved taking a sample from the various streams with suspected supersaturated alkalinity. If precipitation was visible, we had gone too far.
Right: Measure alkalinity analytically. Here, UPi student Victoria Amador is performing the alkalinity test

Hindsight Lesson 3: Prepare for the worst in terms of particle removal when you only have one water sample to base a design from. Another thing that most water engineers know is that you can't base a design off of a single water sample. But, that was all we had, so we did. Also, we didn't know a lot about the well design before arriving in Honduras (another bad idea, in terms of design). One thing we found out when we got here is that the well produces much more water than we need, and the well isn't currently used, so the well was cycled on & off several times during the day to fill a storage tank that we pumped from for the pilot. Each time a well is turned on, particles are brought to the surface. This is usually not a problem, since wells are not normally operated in this manner. Also, many desalination plants will install a strainer to filter out sand and other particles from the well. We did have cartridge filters ahead of our pilot equipment, but we initially had filters with too large of pores installed. Even the smallest pore size filters we had (1 micron) still allowed some particles to leak by. These particles caused fouling of the membranes and are suspected to have also contributed to the precipitation issues found in the RO/NF. We didn't have enough budget to install additional particle removal equipment on this project, but it will be included with the system for further work so that better results can be expected.

Particle Removal.
Left: RO/NF feed tank after 20-micron cartridge filters
Middle: Cartridge filters after one week, one day, and no use (clean)
Right: RO/NF feed tank after 1-micron cartridge filters (there was a vast improvement, but particles were still leaking past the filters)

Bottom Line: We worked hard to be successful

So, what did we learn? And did we meet our stated goals and objectives? I think so. 

Between competing in the Desal Prize and operating in Honduras, we reduced our energy needs by 40%! This means that a smaller PV system could be purchased or that the extra energy could be used for farmers' homes (or possibly sold to recover additional costs). Further energy savings are possible if more of the AC load can be moved to the DC side.

We were able to achieve very high desalination efficiency (94%) with a very challenging brackish water source and only used power produced from our PV system. We produced solid gypsum (the first sample sent to our UTEP lab indicated about 98% purity) and liquid sodium chloride using a salt recovery and enhanced evaporation system. We weren't able to concentrate the sodium chloride enough prior to evaporating it, but previous experiments suggest that we can achieve good enough purity for use in the EDM. Before the RO/NF membranes scaled, we were able to meet the water quality objectives, as estimated from the field analyses. We have identified conservative operational setpoints for how a ZDD system could operate at the Los Almendros location.

And, while we weren't able to demonstrate everything running at the same time, our enhanced evaporation system seems to be capable of evaporating enough of the waste stream to maintain zero liquid waste discharge. With a fan installed and oeprating, we were able to evaporate almost a gallon per hour, which is about double the combined waste flow. 

This project was so much more than the technical objectives. We started the process of transferring knowledge to our UPi partners and to various groups in Honduras. Over the course of two months, we held three training sessions and a public tour at the end of the piloting, we met various UPi professors and students, and we had a chance to meet with Mr. James Watson, the USAID Mission Director Honduras. I am grateful for the opportunity to visit the good people of Honduras and hope that we will be able to continue this work.

Developing Desalination in Honduras. From Left to Right: Clara Borrego, Chancellor Jance Carolina Funes (UPi), Mr. James Watson (USAID), Malynda Cappelle, Ing. Luis Eveline, and Isaac Ferrera (USAID)

We got some great press (Reflections from El Paso, Post 1)

Things got a bit hectic during the last few weeks in Honduras and it has taken me a while to get situated at home again. I do want to take the time to finish up on our activities, so this is the first of at least three that will summarize what we did in September and what we are planning to do in the future.

===============================================

The first few days of September were pretty eventful. Our UTEP-UPi team had the opportunity to be on TV and in the newspaper. On September 1, Clara and I received word that we would be picked up in the morning to go to Televisión Educativa Nacional, TEN Canal 10 along with Luis Eveline to talk about our project. This was pretty exciting nerve-wracking for us (or maybe only nerve-wracking for me since I don't speak Spanish). The show we were on is live and unscripted. So, even though I had some prepared remarks that I was fully capable of reading, it didn't matter. 

Clara and Me - Waiting outside the TV station

We arrived with a few minutes to spare for our appointment. After waiting for a while, we were told that we would have to come back another day because there was an important political event that was being covered live and they weren't going to do the regular show. While this was disappointing, it was somewhat relieving because that would mean that I could practice with Clara a bit more and be more comfortable. 

We asked to go to the restroom and were led through a room where a movie or TV scene was about to be filmed. I really wish that I had a camera to take a picture. The actors were dressed up kind of like the actors in the 10 commandments movie and the green screen setup looked like the desert someplace. I was having fun watching the monitors, which showed how the actors and scene were combined. I have no idea what they were filming. Too bad.

After a bit more waiting, we were told that the show would go on and we were escorted upstairs. My heart was racing. The final bits of the political event were still live, so while we were getting our microphones and places, we got to hear the speech from one of the candidates for president. She was pretty interesting to listen to. I'll be curious to watch how the elections go. Then, we went live. Things moved very fast. It was cool to watch how they went from the offsite event, to weather, to announcements, and then to us. It was a crazy time. I forgot all Spanish. Watching the video now, without cameras, I understand more, but at the time I forgot every word I know. Clara did very well. I struggled with whether I would include the link because of my embarrassment, but it was a good opportunity and so I am including it here for you.

We had a few minutes, so why not take a selfie with one of the anchors? (photo credit: Clara Borrego)

On September 2, we hosted a group of important players in Honduras water and agriculture at our pilot site. This included representatives from the USAID Honduras Mission, SANAA, Fundación Para el Desarrollo Municipal, Federación Nacional de Agricultores y Ganaderos de Honduras, Secretaría de Agricultura y Ganadería Honduras, Asociación de Municipios de Honduras, Programa de Agua del Banco Mundial, and others invited by Ing. Luis Eveline.

The event was held on a day where we (thankfully) had no rain, but also, we had full sun and very little cloud cover, so it was HOT. The event started with Ing. Luis providing a warm welcome to the visitors and introductions of the key people present. Also present was Ari Herrera, who is part of our project team. Ari and Dr. Shane Walker went to graduate school together at UT-Austin and he (Ari) is the connection we (UTEP) had to UPi and Honduras. Ari is originally from Honduras and has extensive experience in water and wastewater treatment. Ari is also very skilled at acting as a translator. He stood by me and translated key portions of comments made by participants and also translated what I said to the group. (note to self: learn more Spanish...). 

Group picture with me talking (photo credit: Victor Zepeda)

Everyone loves our recovered gypsum!
(I think Victor took this photo, but I don't remember...)

After a round robin of comments, we took the group to the well, then provided tours of the desalination and enhanced evaporation/salt recovery systems. La Tribuna, a Honduras newspaper, arrived towards the end of the tours and they interviewed our team and took some great pictures. Their article appeared in the paper the next day. They did a nice job covering the event and I am pleased that we could get such great national coverage to present our project to Honduras.

Here's a link to the article, Honduras ya cuenta con proyecto piloto de desalineación de agua (desalination was misspelled, but that's OK. It can be desalinación or desalinización, I prefer the former since I don't like desalinization in English either).

It's been a while...

It has been quite some time since I updated this blog. A lot has happened, but mostly we were waiting on supplies to be shipped to us and also our container was repaired (just in time for RAIN!).

Tonight I want to share a little bit about the beautiful country we are in. We have had some time to do some sightseeing while the system was shut down. We got to see one of SANAA's water treatment plants (these never get old - hopefully we'll get to see more before we leave!) and got to get outside of Tegucigalpa for a few day trips. Our UPi partners have been kind enough to show us a few of their favorite parts.

SANAA's "Los Laureles" Water Treatment Plant

While our container was being repaired (day 1 of repairs), we took a trip to one of the surface (river) water treatment plants that serves the Tegucigalpa area. I got my notes a little mixed up, but I think the plant supplies 25-30% of the City's drinking water needs. The plant first uses aeration followed by a combination of polymer and flocculant addition with settling tanks to remove turbidity (a measure of bacteria and other undesirable contaminants typical in surface water sources). The next step is a sand filter to further polish the water. Finally, the water is chlorinated prior to being delivered to customers.

We also got to see the water quality laboratory at this facility. This lab performs several analyses, ranging from conductivity (measure of salinity) and pH (measure of acidity), to dissolved constituents like calcium and arsenic, and microbiological contaminants (bacteria, viruses). We hope to be able to have SANAA analyze some of our samples, since shipping is expensive.

Aeration area is seen through the trees. When the reservoir is full, water falls by gravity. When it is lower, they pump to the top of the hill and water falls down.

Clarifying water using settling and filtration (after adding polymer & flocculant)

Dissolved metals analysis using ICP and AA in the SANAA laboratory

San Matías and Las Cascadas de (Rio?) Guaralalao
(We went to the one in Francisco Morazán Department)

(thanks Google for the map)

UPi had a party for its incoming students and we were invited to go. We had a chance to get just outside of Tegucigalpa and get some elevation and even see some waterfalls. The party was pretty neat. We got to eat goat (in taco form, of course!) and there was a lady making delicious pupusas. The incoming students and upperclassmen played a friendly soccer game and there were other fun things to do as well. We got to try our hand at archery (I was so much better at this in elementary and middle school!) and we even had a friendly (mostly) volleyball game.

Prior to the festivities, Ing. Luis Eveline took us to see some lovely waterfalls on the Rio Guaralalao. We had a great time walking around the area and got a few good pictures. The area is very serene and I could imagine escaping to this area regularly if I lived here. We saw a few small farms and evidence of gorgojo (bark beetles) in the forests. It was sad to see so many dead and dying trees, but the views were beautiful otherwise.

The brown areas are dead/dying trees related to Gorgojo

Las Cascadas (one of the views, at least)

Fresh baby corn from Ing. Luis' garden. He also had coffee, bananas, yuca, and a few others that I didn't write down). What a gorgeous location!

La Tigra National Park

(thanks Google for the map)

National Parks are some of my favorite places to visit. I am grateful to have access to beautiful National Parks in the US, so when we were offered a chance to see one of the parks in Honduras, I jumped at the opportunity (plus, we were still waiting on shipments...). We hiked the Bosque Nublado and La Cascada trails to get to the waterfalls, then back on La Cascada and an easier final portion on what I think was the Reales Minas trail. It was about 7 km (4.3 miles), but it had a lot of steep sections. Thankfully, there were plenty of rest stations. It rained on us for the hike back and it was cold, but fun!

My phone (and photography ability) just don't do this place justice. I'm including a group picture and a photo that I thought captured the essence of the cloudy day.

Bosque Nublado (cloud forest)

Group UTEP-UPi pic
(thanks to Clara's phone & a nice woman we met on the trail!)

Valle de Ángeles

(thanks Google for the map)

This is a fun little touristy area close to Tegucigalpa. Several UPi students, one professor (Prof. Sergio Handal), and Rusbel traveled for a short trip, as we were still waiting on deliveries. Clearing customs is always fun with international shipments. Clara and I liked it so much we came back a second time (with more money) since we had to leave early enough for the students to return to classes the first time.

On the first trip, we had pupusas and refrescas naturales (aguas frescas in El Paso/Cd. Juarez). The second time, I had nachos, which were very different from what I'm used to, but they were delicious! Clara had a craving for tacos al pastor. These were also different from what we're used to in the El Paso/Cd. Juarez area, but they looked tasty as well. Between the two trips we have nearly accomplished all of our souvenir shopping for friends and family back home.

The restaurant we went to (second trip) had a place to make your mark. Clara made sure that UPi and UTEP are represented (at least until they paint over it!)

The view from the restaurant. Very pretty here.

Sunday Drive to Comayagua and La Esperanza

(thanks Google for the map)

Chancellor Funes and Ing. Luis Eveline offered to take us to La Esperanza, where a fair had was held (oops, we missed it!) and Comayagua, where the oldest operating clock in Central America is located. Along the way, we saw beautiful vistas and even a few farms. And the food was delicious. We stopped outside of La Esperanza at a restaurant called Finca & Restaurante San Augustin and had fried tilapia and plantains. In Comayagua, we stopped and had these wonderful bean mixtures that are served in clay pots that are heated from below (I haven't learned what these are called yet, but will do so. These need to be in my life.) This was a long day, but was wonderful.

Group pic at lunch (photo credit: Clara Borrego)

Cathedral in main plaza in Comayagua. The clock is the oldest in Central America (and one of the oldest in the Americas, according to some accounts)

Cabbage and other crops being grown outside of La Esperanza

Clara and me in front of the valley outside of La Esperanza

We used some of our recovered salt!

Catching up on our progress - this is the third post from tonight. It's been a hectic week!

One of the great parts about having a high recovery system is that you don't produce much waste. This is also a challenge, at least when you have deadlines for reporting milestones, because you need to operate for several days to obtain enough fluid to test the evaporation system. In any case, we were able to operate the evaporation system for several days to determine what a preliminary capacity for evaporation of our ZDD waste stream. Even with more than double the capacity from what we had in El Paso, we are so far obtaining about a third of the evaporation rate. We are operating our pilot in what could be considered a challenging time of year. It has been mostly cloudy and occasionally rainy the last few weeks. We will try some additional enhancements over the next few weeks to see if we can improve the evaporation rate even further.

More troubleshooting and some thoughts on how to solve problems

In between our participation in two seminars/tours and waiting on container repairs, we have continued to operate our system and attempt to get data. Also, we had a final report due to our funding agency (USAID ) on August 15.

We are continuing to have problems related to the particulates from the Los Almendros well. Particles, like sand and other things, are common with wells. The Los Almendros well is able to produce much more flow than what our pilot needs, so we are cycling the well multiple times per day to fill a tank which feeds our system.Wells aren't normally cycled like this, or, if they are, a sand strainer is installed prior to a membrane system. We didn't know about the particles prior to our arrival, so we don't have this level of pre-treatment. The particles seem to be causing problems in our the RO/NF and EDM systems (here's a link describing our process if this is the first post you have read). We will need to change out our cartridge filters much more often than what is normally done with a brackish well water pilot. This is a fair amount of work and Clara and I, try as we might, just can't get the housings loose all the time.

Cartridge filters and evidence of particles from the well. From top left, going clockwise:
1-Clara and I trying to get the cartridge filter loose (failed). 2-Bottom cartridge filter vs new filter. 3. Three filters showing 1 week's worth of particle filtration, 2 day's worth of particle filtration, and a brand new filter for comparison. 4. sample of the water in the cartridge filter housing with particles rejected by the filter. 5. Scale and particles in the EDM feed manifold.

The high level of alkalinity (Wikipedia describes it pretty well) present in the Los Almendros well has caused precipitation to occur without acid pre-treatment or a lot of water for dilutions. In previous pilots with high alkalinity, acid pre-treatment or substantial dilutions to the concentrate stream were implemented to prevent scale. We have attempted to operate without both of these because increased dilutions reduce the overall recovery and the Desal Prize and piloting objectives prioritized less chemicals. However, sulfuric acid is a common chemical and is relatively easy to procure and use safely. The minimum recovery with dilutions alone will be determined in the coming weeks. Acid pre-treatment will also be attempted to show the maximum recovery possible.

Water samples from pilot. Having solids precipitate is uncommon from the UTEP team's experience (especially precipitation within 4-6 hours!)

The high level of silica and higher than expected rejection by the RO/NF is causing scale in the RO/NF. It is possible that the particles (possibly iron, or sand with iron) from the well are enhancing this problem. We will test operations with a silica bleed (send a partial stream of RO/NF reject to drain) to see if the problem is mitigated. We cleaned the RO/NF and installed a bleed on the RO/NF to test whether it will help with reducing scale buildup. We will attempt to identify the minimum waste flow to protect the RO/NF and estimate the additional evaporation capacity necessary to maintain the zero liquid discharge aspect of the system.

Our container will be repaired over the next few days, so we will have our system off. We expect to be up and running for the next several weeks and hope to have good news to report based off our findings thus far.

Final Training Session

It's been a week since I updated the blog. Time sure does fly! We have been very busy for the last week. I am going to spread the work out into several posts.

Making New Partnerships.
Chancellor Funes (UPi), me (UTEP), and Mr. Rodriguez (AHJASA)
(photo credit: Victoria Amador)

The third seminar was held on August 10 at UPi’s campus. Nine representatives from a combination of regional governmental agencies and a rural water organization called  the Asociación Hondureñas de Juntas Administradoras de Sistemas de Agua (AHJASA) attended. AHJASA is a rural water association that provides benefits such as training and equipment monitoring to its members in various communities in rural parts of Honduras. The representatives from AHJASA included Mr. Lenin Alberto Rodriguez, who works with rural communities. Mr. Rodriguez provided valuable information about the problems with salinity and access to clean water in the southern part of Honduras. The other AHJASA representatives were from member communities in Valle and Choluteca. Since this was the final presentation, UPi students were invited to learn about desalination and the USAID project. Eleven students attended the seminar. After lunch, all participants were transported to the UTEP-UPi pilot site for a tour and demonstration of the equipment.

Final Seminar Participants (photo credit: Victoria Amador)

Visiting the Los Almendros well and talking the AHJASA representatives

We were interviewed onsite - LIVE - during our tour. We were nervous and didn't know she was truly live. There's a joke about now, now, or later, later here. It's really funny watching this after the fact. I understand what I was asked and could have responded (in English, of course), but totally froze. Oh well, it's great that the Hoy Mismo came to learn about our project and I hope they (and others) will come back. We enjoyed meeting the reporter, Gabriela Castillo. Mr. Rusbel got volunteered to be the videographer (it is really amazing what you can do with a cell phone...) for this.

Here's what we wanted to say, English and Spanish (courtesy of Clara):

• The goal of the project is to demonstrate that our technology (called Zero Discharge Desalination) is capable of producing water for both irrigation and drinking purposes while having no liquid waste leave the site. We produce a useful solid byproduct (gypsum) which can be used by farmers to improve soil conditions and a liquid product (NaCl, or table salt) which is used by the technology.

• El objetivo del proyecto es demostrar que nuestra tecnología (llamada Desalinización con Descarga Cero) es capaz de producir agua para riego y potable ademas no deja residuos líquidos el sitio. Se recupera un subproducto sólido útil (yeso) que puede ser utilizado por los agricultores para mejorar las condiciones del suelo y un producto líquido (NaCl o sal de mesa) que utiliza la tecnología.

Fixing Pumps and Making a Video

We have kept our system off because we thought our container was going to be repaired. Since they will need to use grinders, which will make sparks, we want to keep our batteries from charging (and releasing hydrogen). The EDM also produces hydrogen when we are desalinating, so everything has to be off for the repairs. We have had miscommunication about timing, but hopefully we can operate for the rest of the week to obtain data for our final report to USAID.

I meant to include a picture earlier of Mr. Rusbel. Occasionally, Clara and I find something that we can't do without a little help. As I mentioned in my troubleshooting post, we needed to install cartridge filters with smaller pores to protect our membranes from particles from the well. Clara and I were able to get one replaced, but it was leaking. But, we couldn't get the other one replaced because we couldn't get the housing loose. Mr. Rusbel, with his characteristic smile, jumped right in and (with Clara's assistance) tightened the loose one and replaced the other. He's a great guy.

Mr. Rusbel & the cartridge filters (the bottom one is the one we couldn't remove without his help)
(Photo Credit: Clara Borrego)

So, what did we do today? Well, first, we performed surgery. Some of the previous problems with previous precipitation in the EDM feed ended up causing our pump to fail last night. The stack is operating fine, but the pump wouldn't pump. The scale (precipitated salts) were causing friction on the pump. These are really cool pumps, by the way. They have a magnetic drive, so there are very few moving parts. Another cool thing about them is that they use DC energy, so we can use power directly from the sun - no need to convert to AC power! This and other modifications reduced our electrical load by at least 33%. We took apart the pump and scrubbed off the scale. It's working like a champ now!

Before (left) and After (right) pictures of EDM pump

While waiting for the repair guys to arrive today, Jose Eveline (UPi student) came by to get some more footage for a video he is preparing for our UTEP-UPi project. He already has some footage of the system operating and today was slated for interviews. It was a lot of fun. Jose is also the one that took us to get coffee on our first weekend here in Tegucigalpa. 

How to get a shot with a short interviewee (haha!)
(Photo credit: Clara Borrego)

Clara, the sound engineer 

Clara, being filmed