Tech Briefs Magazine - August 2021 - 41

Sustainable Technology
Pre-Treatment Solution for Water Recovery
The solution increases water recovery, prevents mineral scaling, and cuts the volume of
brines in half.
Lyndon B. Johnson Space Center, Houston, Texas
he Pre-Treatment Solution for Water
Recovery was developed by NASA
Johnson to increase the amount of potable
water recovered from the Inter national
Space Station's urine processor assembly
system. Turning wastewater, urine, or seawater
into potable water requires three
important steps: 1) pre-treatment, 2) distillation
or membrane filtration, and 3)
transport and storage of potable water and
brine. This solution is added during the
first step, consequently improving the next
steps in the process primarily by reducing
the formation of solid precipitates.
T
The solution reduces the amount of
precipitates caused by urinary calcium,
sulfate ions, and sulfuric acid, creating
less acidic brines. By reducing these precipitates,
less surface scaling and clogging
occurs in the distillation systems and
more potable water can be recovered.
Also, the solution contains a biocide to
prevent the growth of bacteria, thereby
increasing storage time and the amount
of water recovered.
The solution increased the water re -
covery rate in the ISS distiller from 75 to
90 percent, doubled the volume of feed
processed per cycle, reduced the volume
of brine in half, and eliminated the formation
of precipitate up to 90% water
recovery. The benefits extend to other
steps in the process; for example, less
precipitate has the potential to reduce
the frequency of changing the filters
and the number of filters used per gallon
filtered during the distillation stage.
Furthermore, this pre-treatment solution
prevents bacterial and fungal
growth during storage.
Although the solution was developed
for the ISS distiller, the technology can
potentially be used on Earth to pretreat
contaminated water that is usually treated
with a chemical solution to recover
water from organic-laden, high-salinity
wastewaters. The technology is a simple
additive process that can be scaled to fit
processing demands. The technology
can be used in the transporting or storage
of waste or other water sources due
to the technology's ability to prevent
microbial growth.
NASA is actively seeking licensees to comNASA's
pre-treatment solution has several potential applications such as wastewater treatment,
mining water treatment, and oil and gas exploration and production water supply.
mercialize this technology. Please contact
NASA's Licensing Concierge at AgencyPatent-Licensing@mail.nasa.gov
or call us
at 202-358-7432 to initiate licensing discussions.
Follow this link for more information:
https://technology.nasa.gov/patent/MSCTOPS-68.
Filters
from Tree Branches Purify Drinking Water
Prototypes show promise as a low-cost, natural filtration option.
Massachusetts Institute of Technology, Cambridge
he interiors of nonflowering trees,
such as pine and ginkgo, contain sapwood
lined with straw-like conduits
known as xylem that draw water up
through a tree's trunk and branches.
Xylem conduits are interconnected via
thin membranes that act as natural sieves,
filtering out bubbles from water and sap.
Engineers have fabricated simple filters
from peeled cross-sections of sapT
Tech
Briefs, August 2021
Cov
wood branches, demonstrating that
the design effectively filters bacteria.
New xylem filters were developed that
can filter out pathogens such as E. coli
and rotavirus in lab tests and can
remove bacteria from contaminated
spring, tap, and groundwater. The
team also developed simple techniques
to extend the filters' shelf-life,
enabling the woody disks to purify
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ToC
water after being stored in a dry form
for at least two years.
The researchers took their techniques
to India, where they made xylem filters
from native trees and tested the filters
with local users. Based on their feedback,
the team developed a prototype of
a simple filtration system, fitted with
replaceable xylem filters that purified
water at a rate of one liter per hour. The
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Tech Briefs Magazine - August 2021

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