Water scarcity - Innovation to combat drought | DW Documentary

Key Concepts

• Sponge City: An urban planning concept that aims to manage rainwater by absorbing, storing, and reusing it, thereby reducing flood risk and mitigating drought impacts.
• Buried Diffuser Irrigation: An agricultural technique that delivers water 50 cm below the soil surface, minimizing evaporation and significantly reducing water consumption.
• Water Recycling in Industry: Implementing on-site systems to treat and reuse wastewater, reducing reliance on municipal water supplies and conserving resources.
• Climate Resilience: The ability of a system (e.g., a city, an agricultural sector) to adapt to and withstand the impacts of climate change, particularly extreme weather events.
• Groundwater Management: Strategies to monitor, protect, and efficiently utilize groundwater resources, which are increasingly threatened by overuse and climate change.

Hamburg: Building a Sponge City

Managing Extreme Weather and Protecting Water Resources

The video highlights the dual challenge of managing increasingly extreme weather events, such as heavy rainfall and heatwaves, while simultaneously protecting vital water resources. Climate change underscores the preciousness of water, necessitating efficient and sustainable usage.

Hamburg's Sewer System and the Challenge of Extreme Rainfall

• Historical Infrastructure: Hamburg's sewer system, over 180 years old, was not designed for current rainfall intensities. Public works supervisor Durk Grunut notes that while the old masonry is repairable, the sheer volume of water during downpours poses a significant threat, potentially leading to street flooding as gutters become overwhelmed.
• Urbanization Impact: The extensive use of asphalt and concrete in cities prevents rainwater from seeping into the ground, exacerbating surface runoff and flooding.

Hydrological Monitoring and Modeling for Resilience

• Data-Driven Approach: Hydrologist Andreas Khenbecka emphasizes the importance of measurement for understanding and mitigating water-related risks. He has established 30 weather stations across Hamburg to collect real-time data on precipitation.
• Precipitation Gauge: This device collects rainfall in a container and measures it on a sensitive scale, providing immediate data on precipitation levels.
• Scenario Modeling: Khenbecka uses this data to model the potential impact of extreme rainfall events (e.g., intensity level 8 or 10) to inform urban planning and adaptation strategies.

Simulation Software for Urban Planning Solutions

• Digital Twin of Hamburg: Andreas Khenbecka and colleague Andreas Paya utilize simulation software to create a digital model of Hamburg.
• Address-Specific Forecasting: This model allows for the prediction of water flow and potential flooding at individual addresses within the city.
• Testing Mitigation Strategies: The simulation software enables the testing of various solutions:
  • Diverting Water to Parks: Redirecting excess rainwater from streets into adjacent parks, where the soil can absorb it.
  • Adjusting Topography: Modifying terrain within the model (e.g., lowering certain areas, raising others) to channel water effectively. For instance, a 10 cm adjustment was tested for a ditch.
  • Constructing Small Dams: Implementing small dams to protect properties from flooding. The software immediately calculates the impact of these structures on water flow.
• Successful Simulation Outcome: A test showed that a proposed elevation change successfully directed water towards the park, with water only reaching the edge of the intended area.

The Sponge City Concept in Practice

• Multi-faceted Approach: Hamburg is transforming into a "sponge city" through various measures:
  • Absorption Areas and Parks: Utilizing green spaces for water absorption.
  • Green Roofs: Vegetated roofs that absorb rainwater.
  • Permeable Pavements: Surfaces that allow water to infiltrate the ground.
  • Rainwater Reservoirs: Structures to store collected rainwater.
• Benefits of Sponge City:
  • Reduced Strain During Heavy Rain: Mitigates flooding by absorbing excess water.
  • Lessened Impact During Dry Spells: Retained water nourishes plants during heatwaves and helps cool the urban environment.
  • Win-Win Situation: Protects both drainage and drinking water supply systems.

School Campus as a Sponge City Example

• Redesigned Grounds: A high school in Hamburg has had its grounds redesigned based on Kuhan Becker's simulations.
• Retention Basins: Almost all roof surfaces now drain into retention basins, promoting natural water balance, restoring groundwater, and cooling the climate through evaporation.
• Capacity of Basins: A single basin can hold a significant amount of water (e.g., 7.2 m, 9.9 m, totaling 19 m in one example).
• Water-Permeable Areas: Schoolyards incorporate permeable surfaces that allow rainwater to seep into the soil.
• Sports Field Transformation: Large asphalt areas on sports fields have been replaced with water-permeable surfaces, facilitating groundwater recharge.
• Motivation and Future Generations: Environmental engineer Bo William Friedrien highlights the motivation of seeing simulations implemented and believes future generations will build upon these experiences.

Tunisia: Combating Drought with Innovative Irrigation

The Threat of Heat and Drought in Tunisia

• Scorching Heat and Worsening Drought: Tunisia is experiencing increasingly severe drought conditions exacerbated by climate change, leading to dry subsurface soil and threatening entire plantations.
• Historical Water Management: For centuries, farmers used stone dams to trap rainfall, allowing water to seep into the ground and sustain agriculture. However, this system is no longer sustainable due to infrequent and unpredictable rainfall (e.g., good rain only every 7-8 years).

Bellasheb Shakbani's Buried Diffuser Irrigation

• Agricultural Scientist's Innovation: Agricultural scientist Bellasheb Shakbani has developed an irrigation technique designed to use significantly less water.
• The Problem of Evaporation: Traditional irrigation methods lead to substantial water loss through evaporation, especially in arid conditions.
• The Solution: Subsurface Delivery: Shakbani's technique involves injecting water below the soil surface.
• Buried Diffuser System:
  • Components: Consists of a diffusing part made of gravel (e.g., celissium gravel) that is buried 50 cm below the soil.
  • Mechanism: Water is delivered directly to the root zone, eliminating surface evaporation.
  • Water Savings: This method can reduce water consumption by up to 70%.
  • Application: Four diffusers are buried around each olive tree, connected to a water pipe.
• Impact on Agriculture and Drinking Water:
  • Water Consumption in Agriculture: Agriculture accounts for approximately 80% of water consumption in Tunisia, creating shortages for urban populations (e.g., a city of 1 million inhabitants facing water shortages).
  • Protecting Drinking Water Supply: Shakbani's technique aims to conserve water for drinking purposes.
• Demonstration and Persuasion:
  • Field Demonstration: Shakbani demonstrates the system's effectiveness by showing the moist soil around a buried diffuser after a water injection.
  • Humidity Bulb: The system creates a "humidity bulb" of about 3 meters in diameter and 4 meters in depth around the diffusers, providing ample moisture for root expansion and increased production.
  • Farmer Skepticism: Many farmers remain skeptical, requiring persuasion and visible proof of the system's benefits.
• Economic and Environmental Significance: The fight for water is also a fight for farmers' livelihoods. The government subsidizes these experiments as pilot projects.

Germany: Enhancing Drinking Water Supply with Water Recycling

Groundwater Management and Increasing Demand in Hamburg

• 17 Water Works: Hamburg is supplied with groundwater by 17 water works.
• Summer Heat Waves: During summer, water consumption increases significantly, posing a challenge for water facilities.
• Growing Population: An increasing population in Hamburg further escalates demand for water.

Water Loss During Filter Rinsing

• Groundwater Treatment: Groundwater in Hamburg contains iron and manganese, which are removed by filtering it through sand and gravel.
• Filter Cleaning: The sand filters are regularly cleaned and flushed with drinking water.
• Water Loss: Up to 4% of drinking water is lost during this filter rinsing process, becoming wastewater. This lost water could supply over 30,000 people daily.
• Current Disposal: This wastewater is typically discharged into the sea, requiring evaporation and rainfall before it can be reprocessed.

Innovative Ceramic Filter Technology

• Research and Development: Engineer Dota Magu, in collaboration with Shalotta Cast from Hamburg's Technical University, is researching a special water filter.
• Ceramic Filter Design: The filter contains a ceramic membrane with tiny pores designed to trap solid particles like iron and manganese.
• On-Site Treatment: The goal is to treat the dirty water on-site, turning it back into clean drinking water.
• Potential Water Savings: If successful, this filter could save over 4 million liters of water per day in Hamburg alone.

Testing and Validation of the Filter

• Water Clarity Measurement: Yosha Tetslaf measures the cloudiness of the water before and after filtration.
  • Initial Reading: The dirty water has a high cloudiness.
  • Filtered Water Reading: The filtered water shows a reading of 0.09 FNU, which is excellent and well below the drinking water limit of 1 FNU.
• Mass Spectrometry for Metal Content: To ensure complete removal of metals, a mass spectrometer is used.
  • Results: The outflow contains 0.35 mg of manganese and iron below the detection limit.
• Proof of Effectiveness: The results confirm that the water treatment is working and the membrane is functioning effectively.

Broader Implications and Future Implementation

• Safeguarding Water Supply: Magu's research is a significant contribution to securing Germany's water supply.
• Wider Adoption: The technology could be implemented in many waterworks, recycling rinse water for drinking water supply.
• "Every Drop Counts": This initiative aligns with the principle of conserving every drop of water.

Large-Scale Application and Future Prospects

Tunisian Farm Adopting Buried Diffuser System

• Large-Scale Experiment: A farm in Widref, Tunisia, is now using Dr. Shakbani's irrigation system on a large scale for 4,000 olive trees in a drought-stricken region.
• Historical Context: The farm, once capable of growing grain, is now arid due to global warming and water scarcity.
• Salvation Through Innovation: Shakbani's invention offers a potential solution for agriculture in such regions.
• Addressing Salinization: The farm is located near the sea, and falling groundwater levels have led to saltwater intrusion. Osmain, the farm owner, had to invest in a desalination plant.
• Cost-Effectiveness: The investment in desalination is worthwhile due to the extremely low water consumption of the buried diffusers.
• Remarkable Water Efficiency: The farm uses only 2 cubic meters of water per hour for 4,000 olive trees, a significant reduction.
• Salt Management: The plant removes approximately 22 kg of salt daily, which is deposited in a natural salt lake without environmental harm.
• Pilot Projects and Government Support: The government subsidizes these experiments as pilot projects, demonstrating that agriculture can thrive even in climate-affected regions.
• Shakbani's Goal: Dr. Shakbani, over 70, hopes to see his buried diffuser system used on a large scale (e.g., 30 hectares) with good results, achieving his life's goal.
• Potential for Southern Europe: The system could also be beneficial in southern Europe, which faces increasing summer temperatures and extreme droughts.

Carlsberg Brewery: Pioneering Industrial Water Recycling

Immense Water Consumption in Brewing

• Process Water Usage: The Carsburg brewery in Fredicia, Denmark, uses approximately 2,000 cubic meters of water for its processes daily.
• Discharge: This water would typically go to the drain or a municipal wastewater treatment plant.
• Cleaning and Pasteurization: Large volumes of water are used for cleaning and pasteurization. A single machine can use as much water in a day as a household of two uses in a year.

The Role of the Chief Water Recycler

• Resource Conservation Initiative: Carlsberg created the position of Chief Water Recycler to address water consumption.
• On-Site Reprocessing Facility: The company built a new facility to reprocess water directly on-site.
• Closed Water Cycle: By treating and reusing wastewater internally, the brewery has established a closed water cycle.

Impact and Benefits of the Recycling Plant

• Water Production: The plant produces around 500,000 cubic meters of water annually, equivalent to 500 million liters not taken from the city supply.
• Motivation: The motivation is to ensure future generations have access to tap water.
• Recycling Rate: The system recycles a full 90% of the plant's wastewater.
• Water Savings: In just two years, 1 billion liters of water have been conserved.
• Biogas Plant Integration: The recycled wastewater is used in the brewery's biogas plant, contributing 10-15% of the factory's total heat consumption.
• Pilot Project and Global Application: This in-house treatment plant is a pilot project. Carlsberg operates over 80 breweries worldwide, with a particular focus on water conservation in countries like India.

Achieving Drinking Water Quality

• Purification Process: The purification process is highly effective, producing water with drinking water quality.
• Reuse in Production: This purified water is reused for rinsing and pasteurizing, completing the water cycle.
• Industry-Wide Adoption: The hope is that this technology will be adopted by many industries, not just breweries.

Recognition and Conclusion

• Most Water-Efficient Brewery: The Fredishia plant has been recognized as the most water-efficient brewery in the world due to its water recycling system.
• Call to Action: The video concludes by emphasizing that water is a scarce resource and that conserving and preserving it requires great ideas and pioneers. It highlights the importance of these efforts at home, in communities, agriculture, and industry.