Kibera level 3 hospital

Water desalination plant installed in Kibera level 3 hospital.

Kibera level 3 hospital has received a complete and running water desalination plant to provide the facility clean drinkable water for use. The plant was commissioned by Water CAS Andrew Tuimur and Health CAS Dr Rashid Aman on October 14, 2022.

This water desalination plant is among 28 other plants installed in other health facilities across the country. The plant is solar powered to keep cost of operation low.

Water CAS Andrew Tuimur, WaterKiosk Managing Director Samuel Kinyanjui, Boreal Light CEO Dr Mahed Beheshti explains and Health CAS Dr Rashid Aman during the commissioning of the water desalination plant installed at the Kibera Level 3 hospital, on October 14, 2022

The project is expected to benefit six million people annually and create at least 52 direct jobs and 130 indirect jobs.

The project was initiated in 2020 at the height of the Covid-19 pandemic to support hospitals with clean drinking water after it was realised that potable water was a problem. The plant was installed at the facility by WaterKiosk, a new Nairobi-based company in partnership with DEG (a German company), Boreal Light and the German government.

“Apart from the health facilities facing a challenge accessing clean water for their renal unit, patients had challenges too,” WaterKiosk managing director Samuel Kinyanjui said.

“We have looked at all the gaps we have to fill to improve our health systems. a project like this contributes to that effort because we can provide clean water,” Health CAS Dr Rashid Aman said.

“We have looked at all the gaps we have to fill to improve our health systems. a project like this contributes to that effort because we can provide clean water,”

“The facility has a borehole that produces saline water containing chemicals. Kenyan water tends to be saline.

Health CAS Dr Rashid Aman

The solar desalinisation unit cleans it up to a high degree so water can be used in equipment for renal dialysis,” Aman said.

Nairobi has a water shortage and many estates have borehole water that also comes with high levels of fluoride

The water desalination system is a reverse osmosis filtration system similar to other systems that CESP Africa has installed. The plant operates by removing all dissolved and suspended elements and compounds from the water. The final product of the water desalination process is clean water without any impurities from bacteria, viruses and dissolved salts.

Commercial water treatment system
Water desalination /treatment plant installed in 2 rivers mall by CESP Africa.
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Our water filtration system vs refillable water bottles.

Water dispensers are a silent but integral part of any home or office. Not glamorous by any stretch but when you’re feeling thirsty, it’s just what you need.

Our water dispensers are slightly different because they connect directly to your water system, filter your council or borehole water to give you clean drinking water.

For those seeking a slightly more inconspicuous solution, we have an under-sink system. Same connection to your water system but the system fits right under your sink, with a tap to get your clean filtered water.

Comparison

Both our under-sink and stand-alone dispensers use the same technology to treat your water. They use reverse osmosis as well as other filters to clean the water. To read more about how exactly the system works, read here.

Under-sink / Stand-alone dispenser.

  • Our systems use reverse osmosis, as well as other filters to remove any bacteria, viruses, dissolved salts, suspended solids and any other impurities from your tap water. To find out more about how reverse osmosis works read here.
  • Drinking water is always available provided there is electricity and council/borehole water. The system is self-regulating, meaning you set it and leave it and it will purify water to keep its tank full.
  • Our water filtration system comes with an initial purchase cost and cost of filters, but in the long run is very economical.
  • The systems are easy to maintain, requiring very little maintenance and replacing filters every 6-8 months.
  • The under-sink system is also very discrete, with only a tap to dispense your drinking water visible.

Water bottle dispensers.

  • Majority of drinking water providers also use reverse osmosis to remove impurities from their water.
  • The water bottles require constant refilling.
  • There is the initial purchase cost of the dispenser as well as the cost of constantly refilling, which can accumulate quickly to be expensive.
  • The dispensers require the water bottles to be constantly monitored and replaced.
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Multi-media filter

How a Multi-media filter works.

What is a multi-media filter?

A multi-media filter is generally one grade of crushed rock gravel, two grades of garnet and one grade of anthracite filtration media. The crushed rock is used for supporting the filter media and also to provide even distribution of flow during backwash. The course garnet is used as an interface media between the crushed rock and the finer garnet. The top layer (and coarsest) filtration media is the anthracite.

When is a multi-media filter required?

A multi-media filter is suggested when the Silt Density Index (SDI) value is greater than 3 or when the turbidity is greater than 0.2 NTU. There is no exact rule, but the above guidelines should be followed to prevent premature fouling of filtering membranes (reverse osmosis or ultrafiltration).

Clean effluent from a wastewater treatment plant may also be passed through a multi-media filter to remove any suspended solids.

How does the multi-media filter work?

The larger (but lighter) anthracite coal will be on top and the heavier (but smaller) garnet will remain on the bottom. The filter media arrangement allows the largest dirt particles to be removed near the top of the media bed with the smaller dirt particles being retained deeper and deeper in the media. This allows the entire bed to act as a filter allowing much longer filter run times between backwash and more efficient particulate removal. 

Media cleaning through automatic backwash.

The filter media should be cleaned on a routine basis. The length of the filtering cycle between cleaning sequences is dependent upon how dirty the source water is. Typical filtering cycles are in the 6 to 12-hour range. However, some applications allow for a much longer cycle, or in some cases, a shorter cycle.

The filtering cycle is determined by pressure differential between the influent and effluent gauges. Once the difference is approximately 10 PSID the media should be backwashed.

It is recommended that a filter be cleans at least once a day, regardless of application or differential pressure. The cleaning sequence of a filter system varies from one step (for simple systems) to as many as twenty (for more complex systems.) Regardless of the complex nature of the system, all filters are cleaned by reversing the water flow inside the filters. After backwash, the bed is allowed to settle and re-stratify before a final rinse and then it is placed back into service.

The FRP vessel.

Structural Composite Pressure Vessels offer reinforced fiberglass construction for outstanding performance and durability. Available in capacities up to 1,600 gallons.

A multi-media filter to remove suspended solids after wastewater treatment.
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Domestic borehole water filtration system case study.

We supplied an 800 GPD (3,600LPD) reverse osmosis filtration system to a home in Nairobi county. The client was struggling with borehole water that discolored and had a large amount of suspended solids.

The control panel and a view of the overall system.

The client took a water sample thereafter had it analyzed and got the following results.

Borehole water analysis

PARAMETERValuesKS EAS 12:2018*WHO standardsRemarks
Colour (Pt. Co. APHA Colour)5615015Fail
Turbidity (NTU TUB)83.1255.0Fail
Total Suspended Solids (mg/L TSS)52NDNILFail
Iron (mg/L Fe)6.450.30.3Fail
Manganese (mg/L Mn)0.3170.1Fail
Ammonia (mg/L NH3)1.70.50.5Fail
BACTERIOLOGICAL ANALYSIS
Total Coliforms (cfu/100 ml TC)37NDNDFail
Results from the water analysis

*The KS EAS 13:2018 specifies requirements for packaged mineral water for human consumption. This standard applies to natural mineral water, mineral water, natural spring water, spring water and carbonated mineral water.

The analysis confirmed our suspicions on what might be the main issues with the water. The dissolved iron and manganese were responsible for the colour of the water. 

The findings led the design team to chose a reverse osmosis system, as it would remove all dissolved salts as well as any bacteria present in the water. A plant of 800GPD was chosen to match the needs of the household.

The plant also includes :

  1. Multi-grade sand filter,
  2. Greensand and DMI65
  3. Activated carbon filters.
The three vessels in the system.

How the plant works.

Water from the borehole is pumped into a 5,000-liter raw water tank. A pump directs the water through the first vessel with a multi-grade sand filter to remove any suspended solids. The second vessel contains Greensand and DMI65 which remove iron and manganese in the water. The third vessel contains activated carbon to remove chlorine* in the water.

*The chlorine kills any bacteria and viruses present in the water.

The water is then passed through a PP, Granular activated carbon and CTO filter to further filter out any suspended solids, colour, odors and bad taste from the water.

Another pump then passes the water through the reverse osmosis (R.O) filter to remove any dissolved salts from the water. Finally, tan ultraviolet filter kills any remaining pathogens in the water.

A 5,000 liter tank stores the now filtered water, ready for use.

Raw borehole water and clean water after filtration.

Maintenance

The system is set to periodically backwash the 3 larger vessels, this prevents the filters from getting clogged with suspended solids and other contaminants in the water.

The R.O. filter is periodically backwashed to prevent it from clogging. The system is also set to automatically dose anti-scallant to prevent any buildup on the R.O. membrane.

The PP, Granular activated carbon and CTO filters are replaced as needed.

Spent filters being replaced.
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