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Honduras Interns Progress Report
Date: 9/20/07

Location: Ojojona

Work Completed This Week

Progress in Problem Solving

  • Sed Tanks
    • On Monday September 17th the sedimentation tanks were cleaned and pins were put into the entrance elbow of the second sedimentation tank to hold it into place. Also the lamellas were removed from the second tank to see if a floc blanket would form and see how performance was affected. Initially we saw rising flocs, but we are waiting to hear from Alexis how the tank worked without the lamella.
    • It appears that over the week the incoming turbidity was low but that the three sed tanks were functioning. On Friday September 20th however when we arrived the tank was dirty and flocs were rising. We waited about half an hour and the tank didn't clear up. We then shut down tank 2 and allowed the plant running on 262 L/min to run on two sed tanks. When we left in the morning this appeared to work fine. However, when we returned tank 3 had lots of rising flocs. We shut down tank 3 and put tank 2 back online and the turbidity dropped to about 2.5 NTU after about an hour. We think therefore that we can run on two tanks and that when the tubes fall off the tanks get dirtier.
  • Chemical Feed Clogging
    • We are now using a different type of sulfate that was stored at the Ojojona Junta. It's still the same aluminum sulfate, but comes in 50kg bags and in powder form. We divided the bag into 2 using a scale, so were using the same concentration as with the 25kg bags. The 25kg bags we were using before had small granules (about 3 mm in diameter). In general the powdered stuff mixes in a little easier as long as you add it slowly. If you add it too quickly it forms a large gummy ball at the bottom of the barrel that takes a lot of work to dissolve. The good news is that in the first few days this sulfate didn't seem to sediment at all and remained a clear liquid. The powder rises into the air easily and is irritating to breath. Is aluminum sulfate dangerous? We should look into getting masks for this and perhaps more importantly for the chlorine.
  • Floc tank lamella
    **Carol called APP's distributors and none made or had heard of PVC lamina. Luis is still working on the budget.

Capacitation of plant operators

*Alexis is in charge of the plant this week. We gave him some training Monday and he seems to pick up on things more quickly than Mario and Juan. When we got back on Friday we were very happy to note that Alexis had been taking good care of the plant. When we got here it rained a lot that morning and the water was dirty but he had already upped the dose and was cleaning the distribution tank since it was at about 100 and made a new barrile of sulfate. He made changes during the week to ensure the plant was flocculating and kept a very neat and precise record of everything.

  • Next week Juan is in charge. After that we think they are going to pick a permanent operator and hire a fourth fontanero to cover for that person.

Moroceli

  • Tuesday we met with most of the JUNTA in Moroceli. We discussed how to get better population data, but didn't make too much progress. The information we did get from the JUNTA is in an attached document. We also visited various critical points on the line.
  • Wednesday Antonio and John returned to walk part of the pipe. We covered the first 1.6 km and the last 2.2km with the fontanero from Moroceli. We took elevation every 100 feet and noted the tube type. Data is attached.
  • Thursday we met with Arturo from APP and Prof. Erica and Ing. Roni from Zamorano. We discussed socialization of the project and how we will proceed. The first step is the hydraulic analysis of the conduction line, which we are working on with the engineer currently. Next we will meet with the alcaldia and Junta, hopefully next week. We decided APP staff or someone from Zamorano will interview residents before or after the project to see whether they want the plant and whether they like it. Zamorano will look for a student to document the project for a senior thesis. Arturo was still talking about starting construction Nov 1, although this will depend on the conduction line.

Questions, work for Cornell Team

  • Starting on the Autocad drawings, we realized that we have no template to work from. Was a template ever made for AguaClara plans, with standard layers, layout, scale, border, title, etc? If someone is good with autocad, this would be helpful to have.

Plant Improvement Ideas

  • The entrance to the floc tank should be pointed down so as not put extra pressure on the baffles. They already have a tendency to move down the tank. Having the entrance pointed at the baffles causes extra pressure on the first ones and causes them to tilt creating a disrupted flow path at the beginning and causing problems with the baffles at the beginning.

Plans for the Future

New Laminas

  • Buy new laminas (of a new material) for one module at the end of the tank. We will use the laminas in the module that we replace to replace damaged lamina in other modules.
  • At the junctions between modules, we will use 1.5" pvc caps to accept the spacers from the adjacent module. This allow us to actually connect the modules and still keep the spacers in place. We will try to find a way to divert the inlet flow downward without taking up so much space at the beginning of the tank.
  • Also need to buy materials so make a "cage" at the end of the tank to help support the force and minimize buckling of the connections at the end.

Sedimentation tank

  • Measure the height of the cages in the sedimentation tank to see if they are the same height and try to account for the difference in lamella height in the sed tanks.
  • Also try to find another way to design the cages, need to have support in the middle so that the lamella don't fold over and fall in between.
  • Glue parts of the cages together (the bottom so that they don't come apart)
  • Get materials to put pins in the sedimentation tank

Try experiments with the sedimentation tanks:
First one is to see if we can take one of them offline and still produce clean water.
Second is that we need to cut the entrance pipes to the sedimentation chambers so that the pipe that goes to the floor has holes that are as large as possible.
Third is to completely remove the entrance pipes so that all the flow enters at the beginning of the tank
Get materials to take the water from the overflow chamber away from the plant.
Look into the possibility of buying Ferric chloride, the supplier of aluminum sulfate doesn´t appear to have it on their website.

Trips:

  • Trip to La 34 - not scheduled
  • Trip to Marcala - not scheduled
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