Not all may be favorable to this project, but I will explain what I am trying to do. I work at home, and instead of walking a moderate distance to the bathroom and loosing my focus, I've been, at times, peeing in a 3 Quart Poland Springs water bottle. If you take offense at this, please do not continue reading except to be helpful in the scientific goal. I know this subject won't suit many types of people, so just ignore it if that is your case.
I noticed first of all that urine is not at all as sterile as people say that it is. The rate of growth of bacteria is relatively slow, but as a precaution, I found the need to use additional measures to prevent the growth of bacteria. I settled on the following method: I have two bottles and I add to each bottle about enough salt as can be soluble in the urine and sometimes maybe a little more. The one bottle then fills up throughout the day and is emptied, washed, and refilled with salt. The salt helps to kill the bacteria which would be lingering in the empty bottle. The next day, the bottle stays empty and the other is used.
I would add that I discovered that the bacteria (without the salt) does not usually grow unless the bottle is left with urine for two days. After this, however, that same bottle (without the salt) would retain the bacteria and immediately grow, if used again.
This system works relatively well, so long as it is done every day. It will even withstand 2 days with only moderate growth. (If I should leave it by mistake for longer it can get ugly). Nevertheless, I am still looking to improve upon this. One reason is that, if I drink less water or relieve myself normally, the bottle does not fill in one day. I am looking for someone with knowledge of chemistry to help me find a substance that can be added to this solution which fits a number of common sense criteria. I will also add a list of the substances that I have tried or already considered.
- Safe to be handled and mistakenly touched. Implied that it will not eat through the plastic bottle. I can obtain a suitable glass bottle only with difficulty.
- Something that will not kill a dog or a human through trace amounts, should they drink from the (clean) toilet bowl. For example we put ammonia in toilets, flush it, no problem.
- Very important - something that will not react with the urine to produce gas, thereby causing the bottle to explode or expand. Something that will not (implied) produce a distinctively offensive smell. An example of this would be chlorine.
- (Obvious) That it will be suitable to flush down the toilet.
- Something that is not too expensive, physically large, or heavy in the quantity that I intend to use it. An example of this would be diluted vinegar.
- Something not involving much preparation, easy to obtain, etc.
- Vinegar: A moderate amount of vinegar did not have any effect. More than this would be difficult to obtain and store. Even at 5x the strength, I think it would still require a large amount, and this is not sold in stores that I visit.
- Chlorine/Bleach: I understand that this substance reacts with (things in) the urine and produces gas. It would produce a distinctive pool odor and I believe it can also cause burns.
- Ammonia: Same issues as chlorine - it would produce an offensive gas that burns my eyes.
- Acetic acid: similar to vinegar, except dangerous to handle. I don't even know that it would work.
- L-ascorbic acid (Vitamin C): probably dangerous to handle in a concentrated form and I don't know that it would work. Basically the same as vinegar. I know that it is used as a preservative, so it came on this list.
- Alcohol - might work, smell might be tolerable. I would need to know more about what concentration and amount to buy/use.
- Hydrochloric Acid - no
There is a list of preservatives on Wikipedia, and one that just now caught my eye was Sodium Propionate ($20/lb on eBay). Might not be a bad idea; maybe someone knows about it. I would much prefer something that could be bought in a store. Since this urine won't ever be consumed by humans, we should have more options than common preservatives - maybe I/we could push the PH range out to one extreme to inhibit all growth. Someone more knowledgeable could tell me how/if that could work without becoming dangerous.
Ideally, I think would be something that stops the bacteria growth completely. Next best would be something that gives me an extra day or two if I need it.
Thanks in advance.