■ The one and only technology for liquid purification. The number of ISO 14001 certified sites has surpassed 6,000 (as of the end of March 2001), and certification continues to progress at a pace of 200 sites per month, with momentum accelerating further. Wastewater and waste liquid treatment is invariably cited at these ISO 14001 certified sites.

■ The one and only technology for liquid purification. The number of ISO 14001 certified sites has surpassed 6,000 (as of the end of March 2001), and certification continues to progress at a pace of 200 sites per month, with momentum accelerating further. Wastewater and waste liquid treatment is invariably cited at these ISO 14001 certified sites.
While compliance with legal regulations is fundamental, recent trends show factories increasingly seeking "factory wastewater recycling systems" to minimize discharge. For certified sites driven by continuous improvement, advancing wastewater treatment inevitably leads to "wastewater recycling systems."
Liquid Consand Co., Ltd. is a pioneering venture company developing recycling systems for factory wastewater and waste liquids. Its coolant (grinding fluid) recycling system, in particular, is attracting attention for significantly reducing machining costs on machine tools while achieving zero waste liquid discharge. ● Technical Challenges in Factory Wastewater Recycling. President Kimihiko Okagami explains the motivation behind starting the business:
"I'd long observed factories discharging untreated wastewater. Wanting to address this, I founded the company about 17 years ago. Initially, we focused on purifying lubricating oils. However, since these oils reside in sealed containers and circuits, even thoroughly purified oil couldn't be visually confirmed, preventing proper recognition of our work.
So, I shifted development to purifying machine tool coolant and cleaning solutions, where the liquid state is immediately visible from the outside. That was in 1986." Most factory wastewater and cleaning solutions can be reused or have their lifespan extended by removing the fine particles, bacteria, and emulsified oil mixed in. However, recycling factory wastewater has presented technical challenges until now.
For example, the particulates contaminating coolant used in silicon, ceramic, and glass polishing are 0.4 micrometers or smaller. Furthermore, oil particles fully emulsified and mixed into cleaning solutions have an extremely fine particle size of 0.51 micrometers. Attempting to remove such sub-micrometer particles necessitates the use of sub-micrometer filters.
However, currently only ceramic filters are available, and these quickly become clogged, making them utterly unsuitable for practical use. Consequently, the current approach involves flowing large volumes of liquid over the outer surface of ceramic filters, allowing a portion to pass through the filter via osmotic pressure. Furthermore, for removing heavy metal ions from wastewater, the only options until now have been using polymer flocculants or chelating resins.
However, polymer flocculants required 30-40 minutes for flocculation and sedimentation after addition, necessitating vast equipment areas like sedimentation tanks. Furthermore, substantial costs were incurred due to the large quantities of expensive flocculant required and the treatment of the resulting sludge.
On the other hand, while chelating resins allowed for relatively compact equipment, their regeneration process generated large volumes of concentrated waste liquid, which required polymer flocculants for treatment, presenting further challenges. ● Flocculation via adsorbent, capture via filter. To overcome these challenges, we developed the "SA Filter," a flocculation filtration device utilizing a special adsorbent.
After three years of development, this coagulation filtration unit, combined with various oil-water separation units, provides recycling systems for diverse industrial wastewater streams. Simply put, the SA Filter's principle involves passing liquid through a specially developed adsorbent. This causes fine particles, bacteria, and emulsified oil within the liquid to coagulate with each other, forming clusters approximately 300 times larger. These clusters are then captured by a coarse-mesh filter.
Specifically, 1-micrometer particles can be captured by a 100-micrometer filter, and even 0.1-micrometer particles, previously only catchable by hollow fibers, can be captured by a 10-micrometer filter. Meanwhile, oil that is completely emulsified and spread across the liquid surface also forms large clumps when passing through the adsorbent. However, being a liquid, the oil deforms into long, thin strands and passes through the filter.
Therefore, a density-differential oil-water separator is installed downstream of the SA filter to float the large oil clumps to the surface for recovery. Reports indicate that introducing this SA filter can reduce factory wastewater to less than one-tenth, or even eliminate it entirely depending on the liquid type. "Initially, while customers recognized the product's quality, we faced challenges like years of testing before delivery.
At one factory we supplied, workers used to have to wear masks and nose plugs because the waste liquid smelled so bad. Now, they can even eat lunch inside the factory," says President Okagami. The system has now been adopted by a major automaker's factory, and inquiries are coming in from overseas, including Silicon Valley in the US.


● Cost reduction through recycling system implementation. The company's mainstay businesses currently rest on two pillars: a recycling system for machine tool coolant and a system for removing heavy metal ions from wastewater. For the machine tool coolant recycling system, they developed a system that reduces coolant waste to nearly zero while shrinking the required coolant tank capacity to about one-fifth of conventional systems.
Additionally, in collaboration with Sumitomo Electric Industries, the company is currently developing customized systems for various machine tools and a handheld management system. Meanwhile, for the heavy metal ion removal system for wastewater, in partnership with Sumitomo Electric Industries, it has developed and is deploying a system using SA filters that is compact, low-cost, and keeps running costs low.
This system removes heavy metals such as lead, nickel, copper, and hexavalent chromium without using polymer flocculants. Additionally, we have developed a system capable of recycling the dipping solution (tap water) used in liquid crystal glass substrate processing, which is attracting significant attention. This system continuously purifies and recirculates 160 liters per minute of dipping solution during 24-hour continuous cleaning operations.
A system delivered in September 1997 with a processing capacity of 200 tons/day (order value: 10 million yen) continues to operate continuously with zero wastewater discharge to this day. The price for the SA filter is approximately 2.3 million yen per unit for the standard K350G50 model (flow rate: 60 liters/minute for water, 20 liters/minute for oil).
While offering comparable treatment capacity to systems using hollow fibers (removing 0.1-micrometer particles), ceramic filters (removing 0.3-micrometer particles), and polymer flocculants (removing heavy metal ions), the price is set to achieve initial costs less than one-fifth and running costs less than one-tenth.
While environmental conservation measures are typically viewed as cost factors, the company's policy is that introducing systems like waste liquid recycling should instead enable cost reduction. For machine tool coolant recycling systems, in addition to reusing the liquid, the coolant tank capacity can be reduced to about one-fifth of conventional sizes, allowing for more compact machine tools.
This also offers the significant benefit of substantially reducing the required installation area. Furthermore, based on the principles of Total Product Management (TPM), maintaining machine tools in their initial condition and extending their lifespan is also considered a cost advantage. Domestic production of machine tools (grinding machines) in Japan is approximately 6,000 units per year.
In Japan, we aim to initially target 10% of new machine tools, or 600 units per year, for SA filter sales, ultimately expanding to 60%, or 3,600 units per year. We are also considering global expansion (worldwide production is approximately 24,000 units per year). Regarding patents, we have already obtained four, including international applications and business patents, with three others currently pending.
Like many tech startups, the company faces typical challenges: it has no sales staff, and for major deals, it needs to partner with larger firms. President Okagami is aware that in terms of global expansion, the company is lacking in all aspects: people, resources, and capital. However, it is a fact that this technology is truly unique worldwide. Regarding liquid purification, the company's technology is on par with, if not superior to, that of the top major players.