I read a thread on Reef Central on regenerating GFO. Here is my summary and what I personally do.
The method in brief involves: 1) an overnight soak of used gfo in vinegar to remove accumulated calcium carbonate precipitant, and then following a thorough rinse with fresh water (not RO/DI); 2) a 5 day soak with occasional stirring in a lye solution (sodium hydroxide NaOH)
I use High Capacity GFO from BRS. The normal stuff turns to mush when I tried to regenerate it. 1 gallon of solution treats 1 cup of high capacity GFO, I regenerate 3 cups at a time in a 5 gal bucket; normally 2 buckets at a time.
From research, and believe me I'm not a chemist, 1/2 cup (160g) NaOH in one gallon of water makes a 1molar NaOH solution. So add 3 gal of RO/DI water, and 1 1/2 cups of sodium hydroxide, and 3 cups of spent GFO. The water will get really warm so if you don't use a bucket, be careful. Stir several times a day. I use a plastic PVC pipe to stir and place the bucket(s) in the garage where every time I come and go with the car, I give it a stir. After 5 days, the water is rust colored, and dispose where it's safe. I use as a weed killer or simply down the drain. You can use baking soda to neutralize it if you so desire. I rinse the regenerated GFO 3-4 times in RO/DI water and store wet.
The process is easy and works. Just be cautious as lye can burn you wet or dry. I've regenerated GFO over 5 times over. That's a lot of money saved. You can get a 2lb container of sodium hydroxide food grade powder for about $10. I got mine from AAA chemicals an online vendor. Besides whatever I don't use will make an excellent drain cleaner.
I do need to order more lye so if interested, maybe we can do a group buy..
The method in brief involves: 1) an overnight soak of used gfo in vinegar to remove accumulated calcium carbonate precipitant, and then following a thorough rinse with fresh water (not RO/DI); 2) a 5 day soak with occasional stirring in a lye solution (sodium hydroxide NaOH)
I use High Capacity GFO from BRS. The normal stuff turns to mush when I tried to regenerate it. 1 gallon of solution treats 1 cup of high capacity GFO, I regenerate 3 cups at a time in a 5 gal bucket; normally 2 buckets at a time.
From research, and believe me I'm not a chemist, 1/2 cup (160g) NaOH in one gallon of water makes a 1molar NaOH solution. So add 3 gal of RO/DI water, and 1 1/2 cups of sodium hydroxide, and 3 cups of spent GFO. The water will get really warm so if you don't use a bucket, be careful. Stir several times a day. I use a plastic PVC pipe to stir and place the bucket(s) in the garage where every time I come and go with the car, I give it a stir. After 5 days, the water is rust colored, and dispose where it's safe. I use as a weed killer or simply down the drain. You can use baking soda to neutralize it if you so desire. I rinse the regenerated GFO 3-4 times in RO/DI water and store wet.
The process is easy and works. Just be cautious as lye can burn you wet or dry. I've regenerated GFO over 5 times over. That's a lot of money saved. You can get a 2lb container of sodium hydroxide food grade powder for about $10. I got mine from AAA chemicals an online vendor. Besides whatever I don't use will make an excellent drain cleaner.
I do need to order more lye so if interested, maybe we can do a group buy..
