Sustainable Water Treatment for Camps and Settlements

Q: How many people does one Aquatabs 67mg tablet serve?

One tablet treats 8 to 10 litres of clear water, which is a fraction of one person's daily need. Sphere's planning range is 7.5 to 15 litres per person per day for basic needs.

Tony Miller

1 day ago

7 min read

Sustainable water treatment in a camp is treatment that still holds at least 0.2 mg/L of free residual chlorine at the point of delivery after the first funding cycle, the first fuel shortage and the first delayed shipment. Judge a system by what keeps running in month eighteen, not by what was installed in week two.

What does sustainable water treatment mean in a camp or settlement?

It means the water stays safe without depending on one donor, one truck route or one expatriate technician. Most definitions of sustainability in this sector start with the environment. Ours starts with continuity, because a treatment system that stops is the most unsustainable one there is, whatever its carbon footprint.

The standard to hold throughout is the Sphere minimum: free residual chlorine of at least 0.5 mg/L after 30 minutes of contact at pH below 8, and at least 0.2 mg/L at the point of delivery, with turbidity at or below 5 NTU, per the Sphere/IFRC WASH standards (2018). Sustainable water disinfection is whatever combination of chemistry, storage, power and people lets you meet that line every day for as long as the settlement exists. Camps rarely close on the schedule the funding proposal assumed.

We apply five tests to any design:

Supply continuity. Can the consumable be bought again without a special airlift?
Energy independence. Does the system stop when diesel does?
Operability. Can a trained local operator run and repair it?
Cost per person over time. Not the capital cost, the running cost across years.
Adherence. Do people actually use the treated water, month after month?

Why do so many camp water systems fail after handover?

Because the failure is rarely the chlorine. It is the chain around it. Trucked water is the clearest example. When UNICEF and EU Humanitarian Aid commissioned two solar-hybrid piped systems for Kiryandongo settlement in Uganda in 2025, the release described them as replacing costly water trucking that had been the primary source of water since the 2023 influx, for a settlement of 165,000 refugees. Each system draws on 45 solar panels by day, with generators as backup at night or in cloud, and the build took three months. The target was to raise water availability from 9 litres to at least 20 litres per person per day.

Look at what that tells a buyer. Trucking is fast to start and expensive to keep going. A piped, solar-assisted system takes longer to build and costs far less to run. Neither works as a safe supply unless chlorination is built into it, which is where programmes slip. Treatment gets specified at launch and then left to whoever is on shift.

The Bulletin of the World Health Organization documented the consequence in South Sudan. In Jamam refugee camp, 40 to 58 per cent of households collecting from chlorinated tapstands had no detectable residual chlorine in their stored water, and the authors recommended raising the free residual chlorine guideline to 1.0 mg/L so that 0.2 mg/L survives at least 10 hours after distribution. A treatment programme can look complete on paper and protect almost nobody in the household. We cover the chemistry in why chlorine disappears before it reaches the cup.

Which treatment approach is most sustainable: tablets, sachets or centralised chlorination?

Layer them. Our view is that no single method is sustainable on its own, and a camp that bets everything on one is exposed to the failure of that one.

Centralised chlorination at the source or storage tank is the sustainable core for any settlement with a piped or tankered communal supply. One dosing point, one operator and one test routine protect thousands of people, and it removes the daily dosing decision from every household. Bulk calcium hypochlorite (HTH) belongs here.
Household NaDCC tablets are the sustainable backstop. A tablet is light, needs no power and needs no cold chain. One Aquatabs 67mg tablet treats 8 to 10 litres of clear water with 30 minutes of contact, and cloudy water must be filtered through clean cloth first, per the CDC and Medentech instruction sheet. That makes them the right answer when the tapstand reading drops, a water point is out of service, or families are on the move.
Coagulant-flocculant sachets suit turbid source water that tablets alone cannot handle. P&G Purifier of Water treats 10 litres per sachet and removes Giardia and Cryptosporidium that resist chlorine alone, per the CDC-affiliated Center for Safe Drinking Water. Use them where the source is the problem, not as the default for clear borehole water.

The evidence for household products is real but modest, and honest planning needs that. A Cochrane review of 14 trials and 30,746 participants found that distributing water disinfection products for use in the home may reduce diarrhoea by around one quarter, with low-quality evidence and effectiveness improving with adherence. Read that two ways. Household treatment is worth doing, and it works best as the second barrier behind a protected, chlorinated supply, never as the only one. For the choice between tablets and sachets, the Aquatabs 67mg product page sets out what that tablet is built for.

How do you make the energy side sustainable?

Take diesel out of the daily routine wherever you can, and keep it as the backup. The World Bank notes that prices for solar panels used in pumping systems have dropped by up to 80 per cent, that the panels last around 25 years and need little maintenance (page published 2017, updated 2022). That is the argument for solar pumping at boreholes feeding camp tanks, and the Kiryandongo design shows the realistic version: solar by day, generator when the sun is not enough.

For a borehole-fed settlement, this is also the point at which pump choice and treatment choice meet. A pump that runs reliably fills the storage tank on a schedule the chlorination dose can be matched to. A pump that fails leaves operators dosing an empty tank. SLS supplies solar and submersible borehole pumps from Multiquip and Aussie Pumps through the SLS pump equipment range, alongside the treatment chemistry, so the two are specified together rather than bought from different lists a month apart.

What does a sustainable supply chain for water treatment look like?

It looks boring, which is the point. Four things matter:

Stock in country. A consumable held in Juba can be re-ordered in days. One that must be flown in cannot. In the 2024-2025 South Sudan cholera response, SLS deployed more than 52 million Aquatabs tablets and 3.28 million P&G PUR sachets and the lesson we draw is to order against a forecast, not after a stockout.
Authentic product. Every dosing calculation assumes the tablet is what the label says. Buy from the manufacturer's authorised distributor.
Testing that closes the loop. Chlorine residual testing at the tapstand and again at household level, 24 hours after treatment, is the cheapest sustainability measure in the sector. Without it you are guessing.
Storage that protects the residual. Covered, narrow-necked containers in the household and properly sized tanks at the water point. Sphere asks for at least two clean 10 to 20 litre collection containers per household, narrow-necked or covered, per the same Sphere/IFRC standards. SLS supplies Oxfam and Butyl tanks for the water-point end.

If you want the general case for why water systems and long-term resilience belong in one conversation, our earlier piece on how clean water systems support sustainability covers the principle. This piece is the buyer's checklist.

How do you compare two treatment proposals on sustainability?

Ask each bidder for the same five answers, in writing:

What is the consumable, and where is it held in stock in country?
What is the running cost per person per month once the grant-funded start-up phase ends?
What happens to the water supply if power or fuel fails for a week?
What free residual chlorine will the proposal guarantee at the household, not only at the tapstand?
Who trains and supports the local operator after handover?

A bid that cannot answer the fourth question has designed to the tapstand and stopped there. The South Sudan evidence above is why that matters.

What happened in the South Sudan response?

The outbreak that began in Renk, among returnees from Sudan, shows why continuity wins over elegance. According to WHO AFRO, South Sudan's cholera outbreak, declared on 28 October 2024, reached nearly 100,000 suspected cases and more than 1,500 deaths across 55 counties. A response of that length cannot run on emergency airfreight. The household treatment supply behind our own work, including P&G PUR sachets to 27,344 households in Juba and Renk, depended on in-country stock, customs clearance and last-mile delivery working together, and the Juba cholera case study describes how that chain was built. Distribution of that scale is a capacity figure, not a health outcome, and we do not present it as one.

Frequently asked questions

What is sustainable water treatment in a humanitarian setting?

Treatment that keeps meeting the Sphere minimum of at least 0.2 mg/L free residual chlorine at the point of delivery, with turbidity at or below 5 NTU, over years rather than weeks, per the Sphere/IFRC WASH standards (2018). That requires reliable supply, power, trained operators and household-level monitoring, not only a one-off installation.

Is household water treatment enough on its own?

No. A Cochrane review found that household disinfection products may reduce diarrhoea by around one quarter, on low-quality evidence, with better results where use is consistent, per Cochrane. Use it as a second barrier behind a chlorinated communal supply.

Why does treated water still fail in camps?

Residual chlorine decays in storage. In Jamam camp in South Sudan, 40 to 58 per cent of households using chlorinated tapstands had no detectable residual in stored water, per the Bulletin of the World Health Organization (2015).

Does solar pumping make a camp water system sustainable?

It lowers running cost and fuel dependence. The World Bank reports panel prices down by up to 80 per cent and panel life of around 25 years, per its solar pumping brief. It must be paired with chlorination and a backup power plan to protect supply.

How many people does one Aquatabs 67mg tablet serve?

One tablet treats 8 to 10 litres of clear water, which is the drinking-water capacity for a fraction of one person's daily need, per the CDC and Medentech instruction sheet. Sphere's planning range is 7.5 to 15 litres per person per day for basic needs, per the Sphere/IFRC standards.