Solar Water Disinfection (SODIS)

Location

Makabe, Dar es Salaam, Tanzania

Introduction

World Water Hub is a global coalition committed to reshaping the world’s relationship with water. The organization provides open access to water related knowledge, supports a worldwide network of activists, and promotes practical, community centered solutions. Through initiatives like the World Water Quilt and grassroots water conservation programs, the Hub works to transform awareness into action.

As a World Water Ambassador, my mission is to educate and empower communities by demonstrating safe, low cost water purification methods. My work is based in Makabe, Dar es Salaam, where access to safe drinking water remains an everyday challenge. I conduct household visits to understand existing water practices, demonstrate Solar Water Disinfection (SODIS), guide families on safe water storage, and monitor progress through follow up data collection.

Solar Water Disinfection (SODIS)

Solar Water Disinfection (SODIS) is a simple, low cost, and scientifically validated method for making contaminated water safe to drink. It uses solar UV radiation and heat to destroy harmful microorganisms.

How SODIS works :

• Water is collected in a clean, transparent plastic bottle (usually PET bottles).

• The bottle is filled and shaken gently to oxygenate the water.

• It is placed on a corrugated iron sheet, rooftop, or open ground under direct sunlight.

• After 6 hours of full sunlight (or 2 consecutive days during cloudy weather), the water becomes safe for consumption.
  

Scientific Basis :

• UV-A rays (320–400 nm) penetrate the water and damage DNA and cellular structures of pathogens.

• Heat increases the effectiveness, especially when temperatures rise above 50°C.

• The combined effect inactivates bacteria, viruses, and protozoa.
  

Effectiveness :

• Field studies show SODIS reduces diarrhoea—especially in children—by up to 38 percent.

• It is effective against microbial contamination but not effective for water polluted with chemicals, heavy metals, or toxic waste.
  

Why SODIS Matters for Low Income Communities :

• It requires no electricity, no chemicals, and costs almost nothing.

• It fits perfectly into communities where boiling water is expensive due to fuel costs.

• It allows immediate action without waiting for government systems or infrastructure.
  

  
  

Community Realities in Makabe

Makabe is a community where water is not merely a utility, it is a daily battle. The challenges are multidimensional:

Water Access :

• Many households spend up to half their income purchasing water from trucks.

• Those who cannot afford truck water wake up at 4 a.m. to collect water from “chemi chemi” natural springs.

• These springs usually dry up by 6 a.m., leaving households without safe water for the remainder of the day.
  

Economic Burden :

• Digging a private well can cost Tsh 2 million, far beyond what most families earn.

• Rainwater harvesting helps only during rainy seasons, leaving long periods of scarcity.
  

Impact on Education :

• Children return from school exhausted, only to walk long distances to fetch water.

• Girls often miss school during menstruation because they lack water for hygiene.

• Homework, rest, and personal development suffer due to water duties.
  

Health Implications :

• High risk of water borne diseases such as diarrhoea, typhoid, and cholera.

• Families often drink unsafe water out of desperation.

• Lack of awareness leads to reliance on harmful or ineffective purification methods.
  

Water scarcity in Makabe is not just an inconvenience, it is a barrier to health, dignity, and development.

Impact achieved so far

Households Reached: 42

Key Achievements :

• Awareness to Action Transition - Families are beginning to adopt SODIS, placing bottles outside daily. This marks the crucial shift from knowing to practicing, building long-term habits.

• Community Empowerment - Households are becoming more proactive. They teach neighbours, reuse plastic bottles, and initiate conversations about shared responsibility. Water is no longer viewed only as a government obligation but as a community priority.

• Behavioural Change - There is a growing recognition that safe water practices directly impact health. Families report fewer stomach problems and a clearer understanding of hygiene.

• Data Driven Monitoring - Follow up visits have helped track progress, challenges, and behavioural patterns. This is essential for scaling up and improving future interventions.

Why This Work Matters

Health :

Clean water prevents countless diseases. Children in rural communities are especially vulnerable. Safe water leads to stronger immunity, fewer hospital visits, and improved development.

Dignity :

When people no longer wake up at dawn to fight for water, they regain time, energy, and the simple dignity of living without constant fear of scarcity.

Empowerment :

Reducing water collection responsibilities frees women and children to study, work, build businesses, and participate in leadership roles. Water solutions directly reshape gender roles and community development.

Mindset Transformation :

This project goes beyond teaching a method. It’s about:

• shifting how communities value water

• building ownership and responsibility

• changing beliefs passed from generation to generation

• inspiring collective problem solving
  

When people value water, they protect it. That is the foundation of sustainable change.

Challenges Faced

Illiteracy and Limited Access to Knowledge :

Many residents cannot read, making printed materials less effective. Demonstrations work best but require time, energy, and patience. Scientific explanations can feel abstract to the average household.

Competing Daily Struggles:

When people are overwhelmed with poverty, food shortages, childcare, and work, learning new methods feels secondary. Adoption becomes slow, not due to lack of interest, but lack of bandwidth.

Cultural Mindset and Comfort with Hardship :

Resilience is a strength, but it sometimes creates resistance to change. Many say, “Our parents drank this water; we are fine.” This mindset blocks innovations like SODIS.

Invisible Results of SODIS :

Because SODIS does not produce visible signs like boiling, many doubt its effectiveness. The absence of visual proof makes it feel like “blind faith” to skeptics.

Limited Resources :

Some households lack enough clean bottles, safe drying areas, or sunlight exposure spaces, slowing adoption.

Vision Ahead

Short Term Goals (Next 12 Months) :

• Increase SODIS adoption in at least 40 additional communities.

• Train 20 local champions to support demonstrations, monitoring, and sustained learning.

• Create simple, visual teaching tools that work even in low literacy settings.

  
  

Long Term Goals (2-5 Years) :

• Integrate SODIS education into primary and secondary schools.

• Support local micro entrepreneurs to produce affordable safe water storage solutions.

• Advocate for long term water solutions combining household methods and government infrastructure.

• Establish community networks where water safety is a shared conversation, not an individual struggle.

Conclusion

This project highlights the urgent need for sustainable water solutions in underserved communities. Through awareness, education, and community engagement, families in Makabe are beginning to adopt safer water practices and embrace water as a shared responsibility.

My continued mission as a World Water Ambassador is to empower communities, promote practical solutions like SODIS, and contribute to long term change in water security and public health.