Hiroshima Factory Turns Discarded Bottles and Solar Panel Glass Into Super Sol

Waste Glass Finds a New Role in Construction and Water Treatment

At a factory operated by Cocco Co., Ltd. in Hiroshima Prefecture, discarded glass bottles and glass from aging solar panels become Super Sol, a porous material weighing about one fifth to one sixth as much as ordinary soil. Instead of returning glass to the bottle manufacturing cycle, the plant turns it into a different product used in construction, agriculture and environmental cleanup.

Japan generates approximately one million tons of glass bottles annually. Clear bottles readily enter conventional recycling streams, while colored bottles often face rejection by standard processing facilities. Glass without a suitable recycling outlet has historically gone to landfills, taking up disposal space and wasting material that could serve another purpose.

Cocco accepts glass that lacks viable recycling alternatives, including colored bottles that are difficult to process. Its production line also handles solar panel glass, bringing together an established waste problem and a newer one associated with renewable energy equipment reaching the end of its working life.

Super Sol resembles artificial pumice. Like the lightweight volcanic material, it contains many small holes. Those pores help give it properties useful for filling embankments, reducing the load on foundations, supporting plant growth and, after further modification, removing phosphate from wastewater.

The Hiroshima operation is part of a wider manufacturing network built around technology developed by Trim Co., Ltd. Production began in Okinawa in 1999, and the Hiroshima plant opened in 2010. The technology has since spread across Japan and reached Taiwan.

The product's value comes from doing a different job from the glass that went into it. A bottle rejected by a conventional recycling facility can become a construction material with lower weight, useful drainage properties and applications extending beyond building work.

Why Colored Bottles Need Another Outlet

Colored glass presents a practical problem for conventional recycling. Melting different colors together produces inconsistent cullet, the glass material prepared for reuse, that bottle manufacturers can reject because of its low quality. Clear containers have a more straightforward route back into packaging production.

Japan's annual glass bottle output of approximately one million tons gives that sorting problem a substantial scale. Difficulties with colored glass affect a substantial portion of the total, although no exact share is given. Bottles without another outlet can end up in permanent disposal.

Cocco's approach changes the destination of that glass. The company processes it into an entirely new substance with different physical properties, creating a useful product from material that standard bottle recycling facilities may turn away.

Solar panel glass adds a second stream of raw material. Cocco removes components that need separate handling, then directs the recovered glass into Super Sol production. Accepting both bottles and solar panel glass allows the same manufacturing process to respond to different kinds of discarded products.

How the Factory Makes Glass Expand

Production begins with the collection of discarded bottles and solar panel glass. The glass is dried using residual heat from the production furnace, putting heat already present at the plant to work in preparing material for grinding.

Workers remove impurities before and after crushing. Plastic caps, paper labels and adhesive residues must be taken out so that the glass entering later stages is more uniform. Cleaning is part of controlling the consistency of the finished material.

Ceramic spheres grind the glass into fine particles measuring approximately 200 microns. Screening then maintains standards for the resulting powder. Technicians mix that powder with proprietary additives before feeding it into the burning line.

Temperatures of 800 to 900 degrees Celsius cause the mixture to expand. During this sintering stage, heat helps form the material while gas bubbles become trapped within the glass structure. The process produces the porous, lightweight texture that distinguishes Super Sol from the bottles used to make it.

The transformation is similar to the natural formation of volcanic pumice. The finished product consists of irregular particles ranging from 2 to 75 millimeters in diameter, rather than intact bottles or smooth pieces of glass.

Countless microscopic holes give Super Sol its combination of lightness and structural integrity. Its specific gravity, a measure of relative density, and its water absorption rate can be tailored for different applications. Those properties help determine whether a particular material is suitable for construction fill, planting media or another use.

Super Sol is mineral based and inorganic. Its composition provides physical and chemical stability without corrosion risks, and the product carries Japan's Eco Mark certification. It is described as an environmentally friendly material composed of natural soil components.

A Lighter Load for Embankments and Foundations

Civil engineering is Super Sol's primary market. Contractors use it as lightweight fill in embankments and as backfill, the material placed behind structures such as retaining walls. Its lower density reduces the weight that walls and foundations must support.

Super Sol weighs about one fifth to one sixth as much as standard soil. That difference matters when construction requires a large volume of fill: the space being filled can remain the same while the weight placed on the supporting structure is much lower.

Engineers can blend Super Sol with crushed stone to obtain unit weights between 4 and 11 kilonewtons per cubic meter. Unit weight describes how much a given volume weighs. Adjusting the blend allows engineers to choose a weight suited to a project's structural requirements.

The lighter aggregate also reduces transportation emissions and structural loads on buildings and embankments. Its environmental benefits therefore extend beyond keeping discarded glass out of landfill: the material's weight affects how it is transported and how it performs after installation.

Workers can place Super Sol in confined spaces and on uneven terrain. Installation involves simple leveling and compaction, without specialized curing periods or advanced construction techniques. That workability can reduce labor costs and shorten project timelines.

Uses in Agriculture, Landscaping and Growing Media

Super Sol's pores provide benefits for planting as well as construction. The material offers drainage while helping improve soil aeration and retain water, making it useful for agricultural applications and greening projects.

Drainage, air and moisture all affect the conditions around plant roots. Super Sol's porous structure gives it a role in managing those conditions, with water absorption properties selected according to the intended application.

Other uses include safety gravel, inorganic soil amendments for horticulture and hydroculture growing media. Hydroculture uses a growing medium and water to support plants, giving the recycled glass material another destination outside conventional construction work.

These applications draw on the same basic transformation. Dense discarded glass becomes a stable material containing many small spaces, allowing the finished product to perform jobs that intact bottles and panels cannot.

Modified Super Sol Removes Phosphate in Research

A study published in a peer reviewed scientific journal investigated foam glass derived from Super Sol as a material for removing phosphate from wastewater. Researchers loaded the foam glass with iron and lanthanum, then applied further heat treatment to prepare an adsorbent.

An adsorbent captures substances on its surface. In this study, the researchers used 0.1 percent iron and 1 percent lanthanum, then calcined the material at 350 degrees Celsius. Calcining is a heat treatment used to prepare or change a material.

The modified foam glass achieved a maximum phosphate adsorption capacity of 1.3 milligrams per gram. In domestic wastewater, it removed 99.2 percent of phosphate after 24 hours. The treatment result applies to the material prepared with iron, lanthanum and the additional heating step.

Excess phosphorus entering water from municipal and agricultural sources causes eutrophication. This is the buildup of nutrients that encourages excessive algal growth, leading to harmful blooms and damage to aquatic ecosystems. Removing phosphate addresses one of the substances driving that process.

The study identified the foam glass adsorbent as a low cost option for localized wastewater treatment, including rural areas and developing regions without advanced sewage infrastructure. Such settings need ways to treat wastewater close to where it is produced.

The material performed particularly well at the low phosphate concentrations typical of domestic wastewater. Its equilibrium constant was higher than that of previously developed adsorbents, a finding relevant to how effectively it captures phosphate under those conditions.

The research adds a water treatment application to Super Sol's established uses in civil engineering and growing media. It also shows how further processing can give recycled foam glass a specific environmental task beyond reducing the quantity of glass sent for disposal.

Certifications and a National Quality Standard

Super Sol holds recycled material certifications from prefectural governments including Hiroshima, Okinawa, Hokkaido, Iwate, Ibaraki, Gifu, Shiga, Okayama and Fukuoka. These recognize it as an authorized recycled material for public works, allowing government contractors to specify it for infrastructure projects.

In 2005, the technology entered the New Technology Information System (NETIS), the database maintained by Japan's Ministry of Land, Infrastructure, Transport and Tourism. NETIS catalogues innovative construction technologies and supports their adoption in public infrastructure projects by providing technical verification.

The material also meets JIS Z 7313, the standard established in 2019 for glass foam recycling materials. A common standard creates quality benchmarks across the industry, giving producers and purchasers a shared basis for assessing the material.

Eco Mark certification provides consumers with assurance that Super Sol reduces environmental burdens associated with daily life. Regional recognition includes Okinawa's Yuikuru authorization and Shiga Prefecture's Biwakuru Eco Ship certification, both associated with regional recycling economies.

Regional certification systems often prioritize certified recycled products in government procurement. Public purchasing can therefore create stable markets for the material, connecting waste processing with demand from infrastructure construction and other government work.

From Okinawa Development to a Wider Network

Trim Co., Ltd. began investigating glass recycling opportunities in 1995. It developed a proprietary cullet machine in 1996 and received its first patent for glass processing technology. Production of Super Sol followed in 1999 at an Okinawa facility, after technology assessments by Japan's Public Works Research Center.

The Hiroshima plant, operated by Cocco Co., Ltd., opened in 2010 as the technology expanded from its Okinawan origins to Japan's main islands. The manufacturing network now includes more than 20 production facilities across Japan and one in Taiwan.

Beyond Okinawa and Hiroshima, manufacturing plants have been established in Fukuoka, Hokkaido, Shizuoka, Gifu, Akita, Aomori, Ibaraki, Hyogo, Shiga, Okayama, Iwate, Yamagata, Gunma, Kochi, Miyazaki, Kyoto, Yamanashi, Wakayama and Fukushima prefectures.

The first overseas production facility opened in Taiwan in 2014. The expansion reflects the ability to reproduce the manufacturing process in different locations and continued demand for sustainable construction materials.

The Glass Foam Materials Cooperative Association was formed in 2016 to coordinate industry standards and promote market development. It was certified as a public demand qualified association in 2020. In 2021, Trim received the Minister of Economy, Trade and Industry Award in the Industrial Standardization Business Awards for its contribution to establishing the JIS standard for glass foam materials.

The development of the technology and its industry framework spans several decades:

• 1995: Trim began investigating glass recycling opportunities.
• 1996: The company developed a proprietary cullet machine and received its first glass processing patent.
• 1999: Super Sol production began in Okinawa following technology assessments.
• 2005: The technology entered NETIS.
• 2010: Cocco's Hiroshima plant opened.
• 2014: The first overseas production facility opened in Taiwan.
• 2016: The Glass Foam Materials Cooperative Association was formed.
• 2019: JIS Z 7313 established a standard for glass foam recycling materials.
• 2020: The cooperative association received public demand qualification.
• 2021: Trim received the industrial standardization award from the Minister of Economy, Trade and Industry.

Preparing for More Discarded Solar Panels

Japan's expanding renewable energy infrastructure creates a growing need to manage aging solar panels. As early photovoltaic installations reach the end of their operational lives, the quantity requiring disposal is projected to grow substantially.

Cocco has adapted its process to accept solar panel glass. Aluminum frames are separated and sent into conventional metal recycling, while the glass requires additional preparation before it can enter the Super Sol production line.

Small steel spheres blast the glass surfaces to remove laminates and other coatings. Once prepared, the recovered glass undergoes the same crushing, screening and sintering process used for bottles. Separating the aluminum and processing the glass creates two routes for recovering resources from complex electronic waste.

Municipal programs in various regions are developing similar initiatives to manage photovoltaic waste as renewable energy adoption accelerates globally. These efforts reflect the need to plan for what happens to renewable energy equipment when it can no longer operate.

Cocco's work connects that disposal challenge with an existing demand for construction and environmental materials. Glass that would otherwise require permanent disposal becomes a lightweight aggregate, while recoverable aluminum returns to metal recycling. The approach applies circular economy principles by turning discarded products into inputs for further industrial use.

Key Points

• Cocco Co., Ltd. in Hiroshima turns difficult to recycle colored bottles and solar panel glass into Super Sol.
• The material weighs about one fifth to one sixth as much as standard soil and is used in embankments, backfill, agriculture and growing media.
• Production grinds glass to approximately 200 microns and heats it with additives at 800 to 900 degrees Celsius, producing porous particles measuring 2 to 75 millimeters.
• Researchers modified foam glass with iron and lanthanum and removed 99.2 percent of phosphate from domestic wastewater after 24 hours.
• Super Sol holds Eco Mark and prefectural certifications, entered NETIS in 2005 and meets JIS Z 7313, established in 2019.
• Trim began developing the technology in the 1990s. Production started in Okinawa in 1999, Hiroshima followed in 2010 and Taiwan in 2014.
• The manufacturing network includes more than 20 facilities in Japan and one in Taiwan.
• Solar panel processing separates aluminum for metal recycling and prepares recovered glass for Super Sol production.