The current problem in the field of water pollution is eutrophication, mainly in closed water bodies.

The current problem in the field of water pollution is eutrophication, mainly in closed water bodies.
Eutrophication is the excessive inflow of nitrogen and phosphorus into closed water bodies such as lakes, inland seas, and bays, which causes red tides and blue-green algae.
The mainstream countermeasures against eutrophication have been dredging of sludge and purification by filtration, but no definitive technology for purification has emerged to date.
Top Ecology Co., Ltd. is a remarkable company that has emerged with a revolutionary technology called "hydroponic biological filtration method" in the field of purification of closed water bodies, which had been blocked.
We interviewed Mr. Koki Kudo, president of Top Ecology.
Encounter with the Hydroponic Biofiltration Method.
（Top Ecology Co., Ltd. was established in December 1995, just three years after its founding.
Before founding the company, he had been involved in a variety of jobs in development-oriented industries, such as real estate companies and general contractors.
I was beginning to feel that the work of concreting riverbanks and buying and selling real estate was becoming a little too much for me," he said, when he was asked to help a friend's company enter the environmental business.
This led me to start working in the environmental field in 1993.
In the environmental field, I was originally interested in water purification.
Water purification requires the treatment of huge amounts of water, so relying on electricity would only be costly," he said.
I thought that if we could purify water using the power of nature, it would be a viable business.
That is when they turned their attention to water purification using plants.
It was already known how to directly add aquatic plants and have them absorb nitrogen and phosphorus.
We conducted several experiments based on this method, but sometimes it did not work well.
I thought, "This is not good enough," so I traveled around the country to see water purification systems that use plants.
I also learned that the biggest problem in the field of water purification is closed water bodies, and I became interested in taking on the challenge of purifying lakes and marshes," he said.
It was at this time that I came across the "hydroponic biological filtration method.
In a nutshell, the hydroponic biological filtration method is a water purification method that utilizes the food chain of an ecosystem centered on aquatic plants.
First, suspended constituents such as thiamin and phosphorus in the lake water are submerged by striking the roots of aquatic plants, and then microanimals such as Sakamaki mussels feed on phytoplankton and grow.
Small animals such as dragonflies, loaches, and shrimp eat the microanimals and grow, while their excrement and carcasses are decomposed by bacteria and other organisms to become nutrients for the plants.
The water is purified by humans harvesting the aquatic plants that have absorbed nitrogen and phosphorus as nutrients and taking them out of the system.
The mechanism sounds simple when you open it up, but designing an ecosystem system requires unique know-how.
Focusing on this technology, which had already been patented, President Kudo thought that the "hydroponic biological filtration method" was the definitive method for purifying closed bodies of water.
Focusing on water, he aimed to go public on the OTC market in early 2000.
He signed a personal and exclusive business partnership agreement with Vioxx Corporation, which had the "hydroponic biological filtration method" technology at the time, and began operations.
Our first joint project was the Tsuchiura Biopark, which was awarded by the Kasumigaura Construction Office of the Ministry of Construction in March 1995.
Biopark is a water park located at Tsuchiura Port, the gateway to Kasumigaura, and covers an area of approximately 3,600 square meters.
The water surface is divided into several blocks by wooden walkways, where nine types of plants suitable for purification are grown, including watercress, kusinsai, Japanese parsley, mint, and other vegetables.
As one visitor said, "Some people who have toured the facility have called it an 'urban Oze.'" The facility does not have the hard image of a water purification facility.
It is more like a purification facility that combines the functions of a biotope, which has been gaining popularity in recent years.
The features of the biopark are, in addition to its high purification capacity, its low cost, its beautiful scenery, and the opportunity for citizen exchange through harvested vegetables, to name a few.
In fact, the biopark has a purification capacity of 10,000 tons of water per day, with reliable purification data of 70% for suspended solids, approximately 60% for chlorophyll concentration (which indicates the amount of algae), and 20-40% for nitrogen and phosphorus.
The park is also extremely hydrophilic, and a citizens' group called "Friends of Bio Park" has spontaneously formed to hold cooking classes using the harvested vegetables.
As for costs, the initial cost is 8,000 yen per square meter, and the running cost is 2,500 yen per ton of water treated, which is much lower than other water purification methods.
In addition, vegetables such as watercress, which are currently provided free of charge, will also generate income if a fee is charged.
At the end of 1995, when the Tsuchiura Bio-Park was well received and its future as a business was clear, Top Ecology was established with the developer of the Bio-Park as a director.
This company was finally established two and a half years after we entered the environmental field of business.
The most important characteristic of President Kudo is his energetic way of speaking.
He has been successful in receiving orders for projects one after another with his sales force, while introducing a certain amount of technical development from outside the company.
The company has already received orders from Nagano Prefecture, Chiba Prefecture, Lake Biwa, and other prefectures for the design and implementation of bioparks similar to the one in Tsuchiura, jointly with a major general contractor, and sales are expected to increase from 30 million yen in fiscal 1997 to several hundred million yen in fiscal 1998.
Pollution of closed water bodies is a common problem throughout the world.
We are preparing to expand our business overseas.
We also intend to market the project to local governments as a way to make effective use of rice paddies that remain vacant due to the policy of reducing rice acreage," he said.
Encouraged by the success of the Bio Park, the next goal is to develop a system to convert seawater into fresh water.
Experiments are already underway in Okinawa in cooperation with the University of the Ryukyus and Toyo Construction Co.
When asked why he is so concerned about water, both lake purification and seawater desalination, he replied, "The world's freshwater is becoming increasingly polluted, and it is becoming impossible to use freshwater as drinking water.
In the future, drinking water will become a highly economic commodity, and I believe it will become a business that the private sector will be involved in in Japan.
We always keep that in mind as we move forward with our business.
As a way to raise funds to move forward with this grand project, we are considering going public over-the-counter in early 2000.