Wateroam Diary – Water Project in Floating Village
Read this first-hand account to find out how Wateroam filters helped Chhnok Tru villagers obtain safe and clean water from a river burdened with contamination.
In Southeast Asia, groundwater is a major source of clean drinking water for many communities, and wells are a primary way for them to access it.
However, without sufficient maintenance and care, multiple issues affecting the water supply could occur. Sedimentation can clog the wells and contaminants can leach into the water table endangering those who depend on the well for water.
This article aims to provide an overview of why wells need maintenance and how to do so. We hope that this will be helpful for your organisation’s next rural development project.
Country | Urban Population Using Groundwater | Rural Population Using Groundwater |
Cambodia | 17% | 53% |
Indonesia | 90% | 91% |
Lao People’s Democratic Republic | 77% | 51% |
Myanmar | 72% | 78% |
Timor-Leste | 95% | 81% |
Country |
Percentage of population using safely managed drinking water (2022)
|
Vietnam | 58% |
Myanmar | 57% |
Philippines | 48% |
Indonesia | 30% |
Cambodia | 29% |
Lao People’s Democratic Republic | 18% |
These wells are excavated by hand shovel and backhoe until water can be accessed. The well is then lined with stones, brick, tile, concrete, or other material to prevent the well structure from collapsing.
As open wells are dug by hand, they can only as deep as the surface of the water table. This is because once they reach the water table, the water will erode nearby soil which impedes further progress. On average, open wells are around 15 metres deep and considered shallow wells.
Shallow wells are more susceptible to contamination as there is not enough soil thickness to absorb more contaminants.
These are constructed by driving a small-diameter pipe with a well point into shallow water-bearing sand or gravel. Driven wells are usually driven by hand and are only able to tap shallow water. This type of well on average tends to be 10 – 15 metres deep/ 30 – 50 feet deep.
Some aquifers consist of water-permeable sand and gravel that are harder to excavate by hand compared to digging out soil to reach pools of groundwater like with dug wells. In cases like these, driven wells are better suited to the task.
(6)Drilled wells are constructed through machinery, such as percussion or rotary drilling. Wells bored with a boring machine are known as bored or borehole wells. These wells can be drilled deeper into the ground compared to dug and driven wells to improve access to safer and cleaner groundwater sources.
With the help of machinery to drill or bore through the ground, wells can reach depths of 30 to 300 metres. As the hole bored can reach depths beyond the surface of the water table, these wells have access to more water.
Borehole wells have access to cleaner water as there is more soil thickness to absorb contaminants from the water before it reaches the aquifer.
Rural communities in Southeast Asia tend to have open wells or borehole wells with hand pumps. (7)
Dug wells without casings can collapse, burying access to the water again. Casings are inserted to provide the well with structure. These casings are usually made of sturdy material such as pipes (e.g. carbon steel, plastic, stainless steel) or concrete rings with grout.
Grout usually consists of a mixture of cement, water, and sand to prevent water from escaping through the concrete rings of the well casing.
The bottom of the well casing or pipe has insufficient surface area for water to seep from the aquifer or water-bearing sand into the well. Well screens and gravel packs are ways to increase that surface area that can draw water from the aquifer.
Well screens are attached to the bottom of the casing to prevent too much sediment from entering the well, especially for wells accessing water in unconsolidated material. These are
then surrounded by gravel packs. Well screens need to be slotted to let water enter, such as slotted PVC pipes or steel pipes.
In addition to increasing the surface area, well screens and gravel packs also block excessive sediment from entering the well. This blocks impurities from entering the well and prevents the well from getting clogged too quickly.
For driven wells, the well point serves two purposes: as a sharp point to help drive the pipe into the ground and as a well screen to draw water into the well.
The following signs indicate that your well needs a clean-up (9):
Different steps can be taken to purify different pollutants in well water so that it meets minimum water quality standards. You can also find out more about these standards in our blog post on WaSH and water quality standards.
Dug wells in rural areas tend to have big uncovered openings which can allow pollutants to enter the well. These include organic matter like insects, animal droppings, leaves and dirt.
Over time, algae can also grow in well water that is exposed to sunlight. These can grow into harmful algal blooms which contain cyanotoxins. (10)
When the well water looks more turbid, a lot of sediment has likely built up on the well screen and the gravel packs. This sediment can form through mud, sand, and silt accumulating on the well screen and casing. (11)
Apart from affecting its drinkability, densely packed sediment and encrustation will affect the well’s ability to absorb water from the aquifer, reducing water levels.
Physical pollutants in the well must be cleaned manually using tools like shovels, wire brushes and scrapers. The pollutants are then collected into buckets and lifted out of the well.
A driven well’s pipes are too narrow to be cleaned by hand but can have pressurised air pumped into the system to agitate and loosen physical particles. In some cases, driven wells may need to be re-driven or replaced.
Before deciding what methods you should use to clean the well, it’s also best to inspect the condition of the well first. The well could be old and have a corroded well casing, which means that more aggressive cleaning techniques could damage the well. (12)
(13) Encrustation can occur when scale or mineral deposits in mineral-rich water form crusts or coatings in and around the well screen. Encrustation can take different forms from hard and brittle deposits to soft sludge under different conditions. Encrustation in wells often comes with biofouling.
Biofouling refers to the clogging of water screens by slime deposits created by organisms in and around the well. Bacteria and other microorganisms can occur naturally in the ground or from improperly built sanitation systems.
Treatment methods for encrustation require careful assessment of the type of well and its construction.
For encrustation on the well walls and on the inner side of well screen, physically scraping off the crust using wire brushes and scrapers works. The cleaned-off material can be lifted out of the well in buckets or bailed out.
Crust and scale outside the well screen require chemical treatment like acid washes. Acid is pumped into the well and allowed to remain there for a set period depending on the size of the well, from a few hours to 15 hours.
An inhibitor is used with the acid to limit damage to the pipes and the well casing. Common acids used include hydrochloric acid, sulfamic acid, and glycolic acid.
We currently don’t provide acid wash treatment, but you can learn more about treating encrustation at this Inspectapedia resource. (14)
Shallow wells (15 metres/ 50 feet deep or less) do not have a lot of soil thickness to sufficiently absorb a lot of contaminants.
Nearby polluting sources such as farms or industrial areas can dump their chemicals near the wells which get leached into the groundwater.
These chemicals can include pesticides, chemical fertilizers, sewage, industrial waste and even heavy metals like lead and more.
If left untreated, these toxins can cause health issues ranging from cancer to hormone disruption and altered brain function. Pregnant women and children are especially at risk. (15)
Microorganisms can occur naturally, especially in shallow wells. These contaminants can also leach in from nearby sanitation infrastructure.
These microorganisms include bacteria, parasites, helminths, protozoa, viruses, and cysts. If left untreated, biologically contaminated water can cause diseases such as diarrhoea. Childhood diarrhoea is one of the big killers of children worldwide.
As water quality differs from place to place, it’s best to conduct a water assessment of the community’s water sources that you want to purify to determine which types of water treatment or water filters are required. Below is a list of filtration and chemical processes related to filtration
Physical filtration
Chemical Processes
You can find out more about these different filtration techniques on our water FAQ or contact our friendly team who can advise you on this here.
Water which is full of physical particles and microorganisms is unfit for drinking or everyday use. If the water only requires removing these two issues, filtration might be sufficient for the community’s use.
In these cases, a filter and a hand pump or electric pump to feed the water filter are installed into the well. Below is an example of how this can work for an open well.
Borehole wells can have the filter connected to the spout or have a filter with a built-in hand pump installed in place of the original spout.
As an example of how filtration can help purify water in wells in rural communities, Wateroam worked with Canact Asia, an education and training enterprise, to provide one of our filters using ultrafiltration technology to improve their access to clean water.
With ultrafiltration, the pore sizes are small enough that even some viruses are prevented from getting through. Ultrafiltration’s typical pore size is around 0.01 micrometre (µm) (1µm = 0.000001m). Filtering out these viruses means that ultrafiltration can defend against childhood diarrhoea which is one of the main killers of children under 5 in the world (18). Wateroam’s filter has been certified by WHO. You can check WHO’s certification and report here.
The main source of water for Sekolah Tinggi Agama Islam (STAI) Miftahul Ulum in Bintan, Indonesia is from a few wells located around the school. Pumps and filters were attached to those wells to provide clean water for more than 150 residents. You can read more about this here.
Considering the range of disinfectants and that they need to be carefully measured before being applied to your communities well, we’ve provided the following resources that you can use:
Read this first-hand account to find out how Wateroam filters helped Chhnok Tru villagers obtain safe and clean water from a river burdened with contamination.
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