Water & Wastewater Asia September/October 2019

TECH ROUND UP | 55
Furthermore, KURAGEL can help plants reduce excess sludge. KURAGEL
controls the generation of sludge by preferentially promoting the proliferation
of microorganisms such as bacteria that purify wastewater. In addition,
Kuraray’s wastewater treatment system utilises the self-oxidation mechanism
of microorganisms to significantly reduce sludge.
“This is another advantage of using KURAGEL in industrial water systems –
we can reduce excess sludge because in the KURAGEL system, it only takes
in bacteria and not metazoa and protozoa, so the bacteria can decompose
by themselves. What this means is that there is less bacteria in the activated
sludge tank due to the KURAGEL system retaining bacteria, so there is less
activated sludge produced.”
CHALLENGES MET
According to Mototsugu, KURAGEL was a natural next step in the
company’s technological roadmap. Considered a pioneer in the business of
manufacturing PVA resin, Kuraray’s selection of product offerings ranges
from EXCEVAL (a specially-modified PVA resin that is water-soluble and offers
high water resistance), MOWIFLEX (a PVA-based polymer compound suitable
for thermoplastic processing) and films including the KURARAY POVAL FILM,
used in polarising plates, and its water-soluble cousin, used in agriculture
chemicals, transfer printing and thermoplastic mould release applications.
PVA gel beads after aerobic cultivation
Mototsugu shared more about the challenges the Kuraray team met in
creating KURAGEL, saying, “The most important point of KURAGEL is the
microstructure of the PVA gel. If there are no pores, or the pores are too
small, useful bacteria cannot grow in the carrier. If they are too large, large
microorganisms like protozoa and metazoa can enter. The first problem was
to adjust the pore size of the gel to an appropriate size. Next was to produce
the gel at a reasonable pace, with stable quality.
It was also difficult getting our overseas customers to accept KURAGEL. At
first, it was difficult because we don’t have actual references in each country,
so it took some time for the customer to understand what we had created
and how efficient it was. But now we have some references in each country
so we’re expanding the KURAGEL system. We’ve made a very good effort to
expand the KURAGEL system in Asian markets.”
A look at the microscopic structure of the PVA gel beads
THE FUTURE OF THE WASTEWATER TREATMENT INDUSTRY
The wastewater treatment industry is still growing, according to Mototsugu,
and needs to find the sweet spot between being a local business and reaching
out into global markets.
“Between global and local, water treatment is more ‘glocal’. Each country
has different wastewater treatment programmes, so we try to bring our
wastewater treatment programme to different countries. Therefore, we
have to develop technologies for each area… For example, the Indian
government now promotes making sewage plants, so we developed a very
compact sewage system for the Indian market. And now for Indonesia, many
rivers still contain ammonia, so we developed the technique for removing
ammonia from the river. Technologies should be developed to solve different
situations.” WWA
A water treatment plant using KURAGEL to treat river water in Indonesia
Water & Wastewater Asia • September / October 2019