Filtering Heavy Metals with Wetland and Wicked Weed


“We propose consulting services that use an eco-friendly way to filter heavy metals using constructed wetland with wicked weed for drinking water. This wetland uses a ‘step-by-step’ purification method and plant-based absorbing stick to intensively remove harmful substances including heavy metals.”

Why did we start this project?  

Having diverse backgrounds in French, Chinese, Spanish, and Information Management, but sharing the common interest in international issues lead us to provide solutions to water problems.

Before we selected this challenge, a video about toxic foam in the Yamuna River came to our attention. It was quite stunning that the tributaries of the Ganges River, which are considered sacred to Indians, are rather a threat to them. In India, 400,000 people die every year due to water pollution, resulting in medical costs of 9 billion dollars. After recognizing that the Ganges River, which is used by 400 million people, has serious water pollution due to dead bodies, garbage, and bubble baths, this project was initiated. 

The most polluted sections of the Yamuna River are from Wazirabad barrage to Oklah barrage. Among them, the Wazirabad barrage, Najafgarh drain and Khyber pass drain have the highest levels of pollution.

The Tonga stand drain, Momat drain, Civil Mill drain, Powerhouse drain, and Delhi gate drain, which are located below these polluted sections, are also becoming contaminated. Pollution from the barrages or drains located upstream, not from drainage, has a large impact on them.

Therefore, there is an urgent need for water purification of the Wazirabad barrage, Najafgarh drain, and Khyber pass drain.

The following table is the water quality status of the Yamuna river compared to the drinking water quality standards of the Bureau of India Standards (BIS) and the World Health Organization (WHO). As you can see, the water quality of the Yamuna river, which passes through Delhi, is quite serious compared to the water quality standards. The DO level is very low and this is not good for biological activities. Also, levels of nitrate and phosphate are above the standard. Coliforms, which are fatal if eaten, were detected in more than 700,000 MPN/100ml as of 2018 and more amounts are now being detected.

Especially, the amount of heavy metals including cadmium, chromium, copper, and lead was detected 10 times higher than the standard value, which contains toxic substances. Considering this situation, water from the Yamuna river is not suitable for drinking water. Also, there are possibilities of water-borne disease when drinking water from it.  It also can not be used as bathwater.

How are we going to solve the problem?

What would be the sustainable and eco-friendly way to supply safe and clean drinking water to people near the polluted river?

 (ver. 27/04/2022 00:20 KST)

Delhi has an abundance and variety of environmental assets in the form of the river Yamuna, the Aravalli Ridge, water bodies, forests, and so on. To preserve and utilize these assets, a mix of strategies such as the Master Plan for Delhi 2041 are being prepared by institutions including Delhi Development Authority (DDA).

Since a constructed wetland as a water purification system is an eco-friendly method using the power of the ecosystem, it requires little electrical energy and less maintenance cost. Therefore, a constructed wetland is considered a suitable water purification method for immediate application in India, where infrastructure such as water and electricity is low. 

In addition, heavy metals, which cause fatal problems to the human body, are highly detected in the Yamuna River that passes through Delhi. Considering this, suggesting a solution that can remove these substances is a very urgent matter to protect human health.

Our technology is focused on maximizing the potential of wetlands. We will propose these technologies to the Government of India and provide ongoing consulting services to help purify water in an eco-friendly way. Delhi’s ordinary wetland will eventually transform into a highly effective water purifying environment after adopting our method.

Constructed Wetland Using ‘Step by Step’ Method 

Wetlands are valued as natural pollutant treatment systems that offer a variety of functions such as flood mitigation, recharging groundwater, and maintaining plant diversity. It also removes phosphate and nitrate which are related to the eutrophication of the water. Moreover, 98% of the coliforms die off after losing when competing with the microbial formed in the soil of the constructed wetland, or being killed by ultraviolet rays. In the case of heavy metals, they are removed from the water using aquatic plants that live in artificial wetlands. We propose a constructed wetland that can maximize its effect of itself by using the ‘Step by Step’ method. This cascade system can make the wetland concentrate on removing each substance by differentiating the work into two zones. 

WHICK (Water Hyacinth Stick)

If the purification operation is performed using only the aquatic plants mentioned above, it takes a long time and the sediment from the plants causes another water pollution.

In order to maximize the heavy metal adsorption efficiency and solve this problem, we propose to make the water hyacinth into a stick that does not reproduce while absorbing heavy metals. This we call, WHICK.

Water Hyacinth is an excellent water purification plant known for its excellent adsorption capacity of heavy metals such as lead, copper, and cadmium. But at the same time, it has a nickname called “Wicked Weed” because of its over-breeding effects environmental damages including water current obstruction and inhibits photosynthesis in submerged plants.  So, only the parts excluding flowers and stamens are processed into a bar.

The pieces of water hyacinth become hardened into a paste with a coagulant harmless to the human body. When the stick reaches the heavy metal adsorption limit, the color will change. The wetland manager or WHICK user can check the replacement time simply by checking the color.

What Procedures does this solution have?

STEP 1 / Filtering / IN
Filter floating garbage at the mouth of the wetland by placing a wire fence and reed. The primary filtered water flows naturally into Zone 1 by gravity. The amount of water that flows into Zone 1 can be adjusted to suit the situation through the faucet.

STEP 2 / Removing / Zone 1
Focus on removing a variety of substances that cause eutrophication of the water such as nitrate and phosphate using plants; which is Pistia stratiotes, Monochoria korsakowii, Phragmites Karka, and Canna Indica. These are the plants that have amazing effects on removing nitrate or phosphate, and these are widely used in India’s constructed wetlands for purifying water.

STEP 3 / Absorbing / ZONE 2
Intensively absorbs lead, copper, and cadmium by using plants with excellent heavy metal adsorption capacity, such as Monochoria vaginalis, Salvinia natans, and Hydrilla verticillata. These plants are well known as aquatic organisms with excellent heavy metal adsorption effects without affecting the existing ecosystem.

STEP 3.5 / Using WHICK / ZONE 2
In Zone 2, WHICK, heavy metal absorbing sticks are additionally used to maximize the effects. Since WHICK is connected with a string, it is convenient to replace and manage.

STEP 4 / Releasing / OUT
After the final purification, the purified water is finally released to a nearby barrage.

The effect of applying the solutions

1. Effects on the economical side

We can utilize India’s environmental assets (swamp, aquatic plants, etc.) which would have an economic effect as they are cheaper than existing WTPs. According to India’s Yamuna Action Plan, it costs $150 million to build and maintain one WasteWater Treatment Plant(WWTP). On the other hand, based on the area we planned, the estimated daily throughput after consulting constructed wetland specialists is $1.05 million. With this we can build a constructed wetland with zero maintenance fees. This results in an economic effect of 126% compared to the construction of sewage treatment plant facilities. The cost of water treatment and maintenance of constructed wetlands is also $32.21, resulting in an economic effect of 89,100% compared to sewage treatment plants.

2. Effects on the environmental side

The wetland that has been abandoned is recycled as a water purifying system, which lessens environmental loss. Water hyacinths are also used to absorb heavy metals from water, so it is possible to not only prevent the destruction of the ecosystem due to over-breeding of water hyacinth, but also save the budget wasted in managing work.

3. Effects on the social side

As the number of these constructed wetlands increases, the quality of the Yamuna river will be improved and rejuvenated. New jobs will be created in the process of manufacturing WHICK by recycling water hyacinth. For example, a variety of new jobs can be expected to emerge, such as removing overbreeding hyacinths, transporting removed hyacinths, manufacturing WHICK using hyacinths, and transporting WHICK to constructed wetlands.

Constructed wetlands are economical compared to sewage treatment plants in construction and operation costs and are effective in preventing waterborne diseases because they remove heavy metals and coliforms. This helps reduce spending on the policy budget used to treat waterborne diseases in India. In the slums of India, an entire family receives only 30 to 40 liters of water a day, but assuming that artificial wetlands process 500,000 liters of water a day, 10,666 households can receive additional or larger amounts of water.

As a result, the construction of artificial wetlands, which is based on our solution, is economically, environmentally and socially effective. This will bring us closer to the United Nations Sustainable Development Goal No. 6 “Ensuring access to clean water and sanitation facilities”.  Our solution would contribute towards the following UN Sustainable Development Goal.

Services and main customers

Our main mission is to suggest a solution that purifies water in an ‘eco-friendly’ way and does not harm or affect the environment as much as possible. Rather than focusing on one-time water purification, the ultimate goal is to purify the ‘water source’ so that it can be used as a sustainable resource. In addition, preserving biodiversity by achieving the rejuvenation of the ecosystem is the most important phase of our activity.

We will initially implement a pilot project that can contribute to the local community by receiving crowdfunding from various companies. Through successful crowdfunding, business expansion will be held. Our next step is consulting services which will be provided to the governments and affiliated organizations for the creation of customized constructed wetlands. Below are the consulting services we provide. 

1. Providing advice when selecting a constructed wetland site

2. Suggesting zone customizations for each region and target material

3. Providing a constructed wetland management manual

4. Presenting the WHICK utilization plan and its usage

5. Providing job opportunities related to WHICK production


SWOT Analysis

Artificial wetlands are eco-friendly, sustainable, and also cost less than other technologies. Moreover, it has the advantage of filtering heavy metals by applying WHICK, unlike traditional wetlands.

There are some risks of pests (such as mosquitoes) and odor generation.

A quarter of India is covered with various green assets including wetlands and forests. And also, policies to utilize them such as MPD are continuously emerging. Plus, in the case of water hyacinth, there are sufficient resources because it is over-breeding in India.

Developers should be on the lookout for problems that arise in the process of site selection or other wetlands’ creation policies.

Further utilization of our solution

These constructed wetlands with ‘WHICK’, which are eco-friendly water purification measures, could be applicable for the treatment of harmful substances, especially heavy metals.

Our constructed wetlands can be ‘customized’ depending on the surrounding environment or conditions of the place to be applied. Some countries such as South Korea, America, and Mexico are installing a micro-wetland on their roof for purifying the rainwater. Heavy metals such as lead, nickel, cadmium, and arsenic are discharged into the atmosphere due to the plants which are affected by rapid industrialization. They soon get mixed with rain and snow and move to the soil as it is. These heavy metals are not easily removed by the ability of natural ecosystems themselves and have strong bioaccumulation properties, which can seriously affect human and animal health. So it is important to remove them. If you use wetlands containing WHICK, you can easily get some help to supply clean and safe water to your tap.

Moreover, WHICK can be used in other places individually since it is made in a small and portable size to facilitate the management of artificial wetlands. Needless to say, commercialization is absolutely feasible if further research is conducted. If commercialization is achieved, heavy metals can be removed by putting this WHICK in the water tank of each household. Heavy metals can also be removed from the water which is used for the area of agriculture & nursery.


Ga Yeong KimJi Hyun Nam Min Kyung SongHa Neul Lim
Management Information
Department of Spanish
and Latinamerican Studies
Department of French
Language and Literature
Department of Chinese