Week 3: Monitoring Biosand Filters in Bluefields

¿Tiene un filtro de blueEnergy?

A monkey who lives in a dog house who also happens to enjoy gelatin. A squirrel living on a window sill. Countless numbers of chickens – so many chickens (and baby chicks). Horses, goats, parrots, turkeys and lazy (and sometimes scary) dogs abound and even, sometimes, cats. These are just some of the animals I have seen whilst monitoring the blueEnergy implemented biosand filters of Bluefields, Nicaragua.

Why not?
Why not?

Approximately 900 filters were installed as part of blueEnergy’s WASH (water, sanitation, and hygiene) program across the various barrios (neighborhoods) in Bluefields. The biosand filter is an adaptation of the traditional slow sand filter which uses sand and gravel of precise, yet various sizes to, naturally, filter water. A biolayer forms within the sand and is, essentially, comprised of good bacteria that eat the bad bacteria which comes from contaminated wells and other sources of water. It is of utmost importance to maintain the integrity of this biolayer. The objective of my project here is to observe and test the filters’ performance against the Centre for Affordable Water and Sanitation’s (CAWST) eight parameters. We do this to ensure they are working correctly and to identify filters that are in need of attention.

Filter Monitoring Team: Me with my translator Fulvia (left) and Bidisha (right) with her translator Roxy (front)
Filter Monitoring Team: Me with my translator Fulvia (left) and Bidisha (right) with her translator Roxy (front)

The eight parameters are as follows:

  1. No leaks
  2. Standing water depth 4-6cm
  3. Diffuser in good condition
  4. Top of sand is level
  5. Filter is used once a day (at least)
  6. Filter used for at least one month since install
  7. Water poured into filter is clear
  8. Flow rate ≦ 400 mL per minute

We observe the filters outside and in to gather information before measuring the interior water depth above the sand and the time it takes to filter 400 mL of water. The filter users and their family are good sources of information and provide answers to questions about usage and filter hygiene. Did I mention that houses are extremely hard to find here? Well, they are. Addresses are not your typical number, street name, city, state, and zip code. Here they are based upon land marks, other people’s homes, or just a family name. Luckily, my partner is a local Creole woman (who also speaks fluent Spanish). She knows the layout of the city, many of the people, and is also really good and fun company.

A sampling of paths taken
A sampling of paths taken

Even with a knowledgeable local on my side, it is still quite difficult. Sometimes we know exactly where a house is but must take a perilous journey to get there. Large, steep and narrow hills flanked by barbed wire and rusted out zinc have led us to many a house during our first week. Other homes were accessible only through great bravery such as by crossing a plank that lay atop the ground and river. Some are not so hard, geographically, to find or physically to get to but the occupants’ or neighbors’ dogs make it as such. Let me just remind you that the humidity levels are well into the 90’s most days and that we are painfully close to the equator. In other words, it is muy caliente – very hot! What stands out more than the forbidding terrain and dogs on my expeditions are the people who live in the houses we are searching for and their neighbors. Never in my life have I met a more accommodating group of people as those here in Bluefields. The people always (well, at least 99% of the time) welcome us in with a smile and answer our questions honestly. Their children are the most responsible and respectful that I have had the pleasure of meeting (and super cute too). Everyone seems to know everyone else – a characteristic that had become foreign to me. People are always willing to help and that has greatly benefited my mission.

Monitoring filters
Monitoring filters

So far we have monitored 180 filters and we have noticed that a majority of the recipients are taking good care of their filters and are knowledgeable about operations and maintenance. Regardless, we still get some who are uninformed such as the family who regularly removed their sand from the filter, washed it, and replaced it – not good for the biolayer. When we do come across a family who needs assistance, we provide verbal guidance and, if needed, recommendations for remediation of the filters. A glaringly obvious deficiency in most of the filters comes from their composition, not user error. You see, when the original fleet of filters were produced the sifter that was utilized to create the inner sand and gravel components was not the correct size. This means that the majority of the filters we test have a fast flow rate (400 mL in less than a minute). This is troubling because the water may not be spending enough time in the filtration phase, thus letting in pathogens. A new sifter has been ordered but is coming in from Honduras. Upon receipt of the sifter, it is hopeful that the gravel inside the filter will be changed out for a more effective size.

Biosand filter users: a Grandfather with his Granddaughter. They were so nice and had such a sweet family.
Biosand filter users: a Grandfather with his Granddaughter. They were so nice and had such a sweet family.

All the information is recorded and transferred to a spreadsheet that we created with the most up-to-date information, including a GPS point for each house (you are very welcome future filter monitors). This information is then taken and populated into a map of the area and when a filter point is selected you can view an image of the family, demographics, and information about the filter. I am looking forward to continuing my work and learning more about the Bluefields filters and the families that use them.

2 Comments

  1. Sounds like a very interesting and rewarding mission you have here, Clarissa. I love the reading about the field work you are doing.

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