Edge Collective

Other than minimizing and monitoring chlorine and humic acid concentrations, there is essentially no foreseeable way of removing THMs at the water treatment plant. Water system engineers want there to be a chlorine residual (often referred to as “the residual”) in your distribution pipes because this keeps your water safe from potentially harmful bacteria and viruses as it travels through the distribution system to your home.

Unfortunately, it is this excess chlorine that reacts with organic matter present in your pipes to create THMs. Ultimately, this decision to chlorinate versus have no THMs is a tradeoff between safety from microbes and safety from THMs.

Because there are so many different treatment products on the market, it is difficult to give a blanket statement about removal of THMs with home treatment products. In general, the easiest way to reduce THM’s in your tap water is to consider buying a National Science Foundation certified carbon filter for your drinking water at home; ensure that it is certified specifically under the NSF/ANSI Standard 53 Certification for THMs. Point-of-entry systems are recommended in order to protect you both from ingesting THMs as well as inhaling them, for example while doing the dishes or showering.

Relevant test from Simple Labs -- VOC Water Test -- $140 -- https://mytapscore.com/products/volatile-organic-compounds-water-test

Kon Tiki biochar production https://www.youtube.com/watch?v=1o0QqePtNM4

Suggestion not to grind biochar into a fine powder https://www.youtube.com/watch?v=9boXHuzMFsA

Josh Kearns, small gasifier & water filtration https://www.youtube.com/watch?v=o1Op6nnO9H4

Relevant paint cans on Amazon for $12

Similar design for gasifier from paint can https://www.youtube.com/watch?v=vzc1r3EfNSg

Follow the above design for a test

US Biochar initiative https://twitter.com/USBiochar

Collecting total THM sample https://www.youtube.com/watch?v=1Qv5BbPKnQw

Standards for THMs in water https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6985399/

Josh Kearns -- Small scale study of biochar -- very small column

Josh Kearns presentation, TTHM

Academic presentation:

Slides:

http://www.aqsolutions.org/images/2016/10/Kearns-UNC-2016.pdf

Biomass

The return of biomass https://www.youtube.com/watch?v=Ps6Rn-i9t1Y

Solar still

Post Carbon Institute Fellows

Cindy Parker https://www.postcarbon.org/our-people/cindy-parker/

https://www.postcarbon.org/public-health-and-medicine-in-an-age-of-energy-scarcity/

Stephanie Mills https://www.postcarbon.org/our-people/stephanie-mills/

Tue Oct 10 08:29:02 PM EDT 2023

D-Lab projects

Dan Sweeney -- https://d-lab.mit.edu/about/people/daniel-sweeney

Cooling chamber -- https://www.cooling-chamber.mit.edu/

Article on D-Lab Evaporative cooling https://d-lab.mit.edu/news-blog/news/addressing-food-insecurity-arid-regions-open-source-evaporative-cooling-chamber

Article on clay pots https://d-lab.mit.edu/research/evaporative-cooling-vegetable-preservation/clay-pot-coolers

Article on charcoal cooler, engineering for change https://www.engineeringforchange.org/solutions/product/charcoal-cooler/

What about biogas?

What about compressed air?

Tue Oct 10 10:05:13 PM EDT 2023

EPA method for TTHM -- https://archive.epa.gov/region1/info/testmethods/web/pdf/501_3.pdf

"A New Method for the Fast Analysis of Trihalomethanes in Tap and Recycled Waters Using Headspace Gas Chromatography with Micro-Electron Capture Detection" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5451978/

background on TTHMs https://caslab.com/News/testing-for-trihalomethanes-in-your-water-tthm.html

removing tthms with activated carbon https://wcponline.com/2006/06/27/trihalomethane-removal-activated-carbon/

When designing systems with water that has been previously chlorinated, GAC is used to remove the TTHMs directly. One method employed to determine how long GAC will last removing TTHMs is to perform a carbon isotherm test on the specific water. Exact details on how to perform the test are available in ASTM International test method D 5919, Determination of Adsorptive Capacity of Activated Carbon by a Micro-Isotherm Technique for Adsorbates at ppb Concentrations. The test results are plotted according to the empirical Freundlich equation. As shown in Figure 2, the residual concentration of the THM in solution is plotted on the x axis and the amount of THM adsorbed per unit weight of activated carbon is plotted on the y axis.

Relevant carbon isotherm test https://www.jstor.org/stable/25042618

Test methods for activated carbon https://activatedcarbon.org/images/Test_method_for_Activated_Carbon_86.pdf

https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=2000CIAZ.TXT

Really nice documented on activated carbon:

https://www.awwa.org/portals/0/files/publications/documents/samples/activatedcarbonchap1.pdf

Tue Oct 10 10:13:07 PM EDT 2023

CO2 monitor https://hackaday.com/2023/10/10/pocket-co2-sensor-doubles-as-smd-proving-ground/

based on original post: https://bitbanksoftware.blogspot.com/2023/04/building-pocket-co2-project.html