Some will claim urine is sterile and doesn’t smell. Horse hockey. No matter how careful you are, urine is loaded with nitrogen (urea) and potassium. Bacteria will find their way in, and the potent brew will ferment into a nasty solids-laden syrup within a few days.
Unlike a holding tank, where the purpose of treatments is to support a healthy biome, the best urine treatments are like those used in portable toilets to stop bioactivity dead. Urine treatments modify the urine chemistry so that fermentation cannot take hold and any ammonia that is generated will be retained in solution. They really work.
Like holding tank or portable toilet treatments, the greater portion of the treatment is added to the tank before use. However, just as we recommend spraying a diluted odor treatment in the bowl of holding tank-type heads (see PS June 2017, “A Simple Solution to Toilet Bowl Stink”), the urine diverter can also benefit from a light spray of urine treatment after each use to prevent the build-up of scale and stains and to prevent odor from the funnel surface itself.
Dilute as recommended. Add a little Febreeze or other odor neutralizer if you like. Nilodor includes a mild fragrance and citric acid has a barely noticeable citrus odor.
Never add bleach to the urine container. The hypochlorite will react with the urea, creating dangerous amounts of chloramine gas.
WHAT WE TESTED
Sugar, white vinegar, CLR (lactic acid), citric acid, Wet-And-Forget, and Nilodor’s Urine Digester.
HOW WE TESTED
Sugar, vinegar, and Nilodor doses were based on manufacturer and user suggestions. Lactic and citric acid doses were based on equivalent morality (a measure of capacity) to vinegar. We exposed the test bottles to the air for two days to inoculate them with ambient bacteria and then sealed them up for another five days, checking them for odor every two days. We also tested them as sprays to keep the funnel clean and odor-free.
Fresh urine has a relatively mild smell, which was slightly reduced by sugar and eliminated completely by the acid products and Nilodor, with citric acid and Nilodor in the lead. Acids reduce the volatility of alkaline gases, including ammonia and trimethylamine, which are generated during the breakdown of urine, by converting them into nonvolatile forms which stay in the water. The pH is also reduced enough to inhibit fermentation. Nilodor uses enzymes.
All of these are nontoxic to the environment, biodegradable, and will not interfere with urine disposal.
VALUE GUIDE: ODOR SUPPRESSION FOR URINE
|MANUFACTURER||NONE||GENERIC CANE SUGAR||GENERIC VINEGAR||GENERIC||JELMAR||WET-AND-FORGET||NILODOR||ODORBAN|
|ITEM||--||Cane sugar||White vinegar||Citric acid||CLR||Moss, Mildew, and Algae Stain Remover||Urine Digestor||Deodorizer|
|ACTIVE INGREDIENT||--||Sucrose||Acetic acid||Citric acid||Lactic acid||Benzalkonium chloride||Enzymes||Benzalkonium chloride|
|CONCENTRATION (%)||--||100%||5%||100%||25%||Not listed||2%|
|$ PER GALLON||--||$4||--||$22||$30||$28||$21|
|$ PER POUND OF ACTIVE INGREDIENT||--||$1.30||$9.41||$15||$10.35||$14.11||--||$9.88|
|OUNCES / GALLON||--||4 oz.||4 oz.||0.5 oz.||1.2 oz.||0.5 oz.||2 oz.||2 oz.|
|TEST DOSE g/ml||--||3.1g/ 100 ml||3.1ml/ 100 ml||0.5g/ 100ml||0.93ml/ 100ml||0.39ml/ 100ml||1.55ml/ 100ml||1.55ml/ 100ml|
|ODOR (2 DAYS)||Bad||Strong||Barely noticeable*||None||None||None||None||None|
|ODOR (7 DAYS)||Very strong||Awful||Very noticeable||Noticeable||Noticeable||Noticeable||Noticeable||Noticeable|
|$ / GALLON OF URINE TREATED||--||$0.33||$0.13||$0.47||$0.40||$0.12||$0.44||$0.33|
The idea is that like making jelly, if the solution is strong it will stop bacterial action. The actual result was cloudy urine, a bacterial scum formed on the surface, and after a few days, and a horrible skink far worse than if we had done nothing at all. We tested 1/2 cup/gallon.
Bottom line: This experiment stunk.
By adding a few inches to the bottle before starting, the pH is lowered enough to prevent fermentation. In practice, we could still smell the vinegar, but not much else. A favorite among users and manufacturers, it is economical and widely available. (1/2 cup/gallon of holding tank)
Bottom line: Traditional, effective, and the Budget Buy.
For the first few days it is slightly more effective than vinegar, but if you leave the urine in the bottle for more than three days then the vinegar takes a slight lead. It is better at cleaning the bowl, and it requires less storage space because it is a dry powder; a 5-pound bag has the same effectiveness as 4 gallons of vinegar. (2 tablespoons/gallon of holding tank, or 1 teaspoon per pint to use as a spray)
Bottom line: Recommended.
LACTIC ACID (JELCO CLR)
As the PS choice for best descaler we thought it had a good chance. It did kill the smell at first, but it created a fine precipitate in the jar and the smell got worse after three days. (3 tablespoons/gallon of holding tank or 1 teaspoon/pint to use as spray)
Bottom line: A good choice for cleaning the diverter, but not as a sole treatment.
WET-AND-FORGET MOSS, MILDEW, AND ALGAE STAIN REMOVER
A popular brand for home cleaning Wetand- Forget has the same active ingredient as Odorban, but five times the concentration, making it the least expensive source of BAC we know of.
Performance was similar to Odorban. Use a ratio of 1 tablespoon per gallon of holding tank, or 1 teaspoon per pint of water to use as a spray for cleaning or fighting surface odor.
Bottom line: This is not a good choice for this particular use.
NILODOR URINE DIGESTOR
Testers detected no odor for the first two days, only the mild fragrance of the product. For the next 7 days it remained mild, less than vinegar and citric acid, and orders of magnitude better than raw or sugar-treated urine. It has half the storage space of vinegar. (1/4 cup/gallon of holding tank, or 1 tablespoon/pint to use as a spray.)
Bottom line: This is our Best Choice for odor control.
C-head suggests this formula (1/4 cup Odorban/gallon of holding tank, or 1 tablespoon Odorban/pint to use as a spray) for spraying the its urine diverter. It is based on benzalkonium chloride (BAC), a chemistry we have found effective on many mold and odor problems around the boat. We didn’t find it as effective as other products in fighting urine odors.
Bottom line: Recommended by CHead but we were less impressed.
Except for sugar, all of the treatments were quite impressive for the first few days, and there is really no reason to leave it longer than that.
After 7 days it was less than pleasant to stick our noses in the jars, but still several orders of magnitude better than the rip-your-nose-off stink of non-treated or sugar-treated urine. We recommend spraying down the urine diverter after every use to keep it clean and to supplement the initial treatment. Just keep the spray out of the solids bucket.