Project 3a


A Novel Solution for Safe and Productive Use of Wastewater


Pre-treated drain water is rich in nutrients that can be used for agricultural purposes. Unfortunately, harmful pollutants, like heavy metals, pathogens and micropollutants are still present. For safe water reuse, these pollutants have to be removed. Our aim is to recover the nutrients and remove the pollutants by developing compact, robust and nature-based Vital Urban Filters (VUFs). This water treatment system will be able to produce safe reusable, nutrient rich water for agricultural purposes while having an added social value through the growing of plants.

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Pre-treated drain water (project 2) is nutrient rich (nitrogen and phosphorus) but also contains pollutants. These pollutants, such as pathogens (bacteria, viruses and protozoa), heavy metals and emerging micropollutants (personal care products, hormones and pharmaceuticals), can pose a serious risk to human and environmental health risk. For safe reuse, it is crucial to remove these pollutants from the treated effluents.

As agriculture puts a heavy burden on the available water supply, often unsafe water containing pollutants is used for irrigation. As the pre-treated drain water contains plentiful nutrients and elements suitable for plant growth, it is an excellent source of irrigation water, once hazardous pollutants are removed. This type of water quality makes nutrient recovery possible directly through plants growing on top of the filter or indirectly by producing nutrient rich irrigation (fertigation) water. The possibilities for floriculture increases social acceptance and economics of our technology.   



The research in our project will start with the selection of filter materials with improved pollutant removal characteristics and plants that are able to grow on (treated) Barapullah drain water. Using the selected filter material and plants, a small scale Vital Urban Filter (VUF) will be constructed. Research will then focus on removal mechanisms of a variety of pollutants. Finally, this information will be used to investigate and improve the efficiency of the system and to develop the design criteria for full scale application.

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The operational principle of VUF system is based on the concept of traditional submerged vertical flow constructed wetlands. By combining different filter materials, compact filters can be built that require far less surface area. In order to develop these systems, the working principles and treatment processes occurring in wetlands need to be better understood and translated to the more efficient filter material(s) used in VUF.

As the removal of heavy metals, pathogens and micropollutants is essential for safe water reuse and social acceptance/perception, the removal processes of these pollutants will get special attention in our project. To further understand and improve pollutants’ removal, the various physical, chemical and biological processes that occur in VUF will be researched.

Different filter materials and plants will be tested for removal efficiencies for various pollutants. Using the most promising plants and filter materials, a small scale VUF will be constructed. Using this system, different mechanisms, such as adsorption, biodegradation and inactivation involved in pathogen and other pollutants’ removal will be studied.

This pilot filter will be able to treat up to 100 litres of wastewater per day. The gained knowledge will then be used to design and construct a larger pilot plant. Ultimately, a compact, nature-based, wastewater (post-) treatment system in India, will be developed and implemented that can handle up to 1000 litres per day.



The Vital Urban Filter is based on the concept of conventional constructed wetland, commonly used in decentralised wastewater management. By using efficient filter materials, a smaller footprint can be achieved. The high porosity and surface area of filter materials make them the perfect biomass carrier that has the benefit of improved sorption and degradation processes. The removal efficiency of the filter can be further improved by growing plants on top of the filter.


Our post-treatment technology offers safe reusable irrigation water which will lead to less pressure on existing potable water sources. The added value of the compact filter is the ability to produce flowers on top of the filters which can be sold. This unique aspect improves social acceptance through providing a source of income and aesthetically appealing green space in urban setting. By sharing our knowledge with stakeholders, (existing) constructed wetlands can be improved to increase the access to safe and clean reusable water.

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Safe reuse of effluent

The envisioned Vital Urban Filter can produce nutrient-rich and safe effluent that can be used for irrigation (fertigation water) by farmers, thereby improving the availability of potable water. 

Source of income

The added value of growing plants and crops could be a local source of income. Ornamental plants, flowers but also fibrous plants could be grown. This unique feature could improve the economics and social acceptance of water reuse using Vital Urban Filters.

Knowledge creation & dissemination

Disseminating the new knowledge among different stakeholders can contribute to the goal of achieving environmental and human health concurrently while providing a safe source of reusable water and leading to the improvement of existing wetland systems.



The developed technology will be able to provide a compact post treatment solution suitable for urban areas. That produces safe reusable water for irrigation purposes. Our technology has the following features:

  • Safe, nutrient-rich irrigation (fertigation) water
  • Flexible: stand alone or combined with other technologies
  • Modular and compact design makes it easy in use
  • Capacity to treat wastewater with varying concentrations of pollutants 
  • Aesthetically pleasing green space – reducing heat island effect
  • Urban farming


The project is a collaboration between the Indian and Dutch research institutes: Indian Institute of Technology Delhi and Wageningen University and Research.    

Our contributing partners are:

  • LeAF uses their experience in the development and implementation of localised water treatment and sanitation systems to help us design the filters.
  • Kilian Water assists us in designing the filters and will support us on the effectiveness and reliability of the constructed filters.
  • Drainblock provides materials and expertise for building urban filters in both lab and pilot scales.
  • Greenyard Horticulture provides expertise on the selection of crops and filter materials.
  • RIKILT provides assistance on developing analytical techniques for testing emerging pollutants and antibiotic resistance.