RO Scheduling

[SeanD]

I'm curious how people use the RO in their work/boiling schedule.

Let's say you work during the day, collect at 5 p.m. and come back with 100 gallons. If you have a 125 gph RO, does it actually process that sap in under an hour and you are boiling around 6?

Or is it a much slower rate and you hold the 100 gallons to RO it during the next work day, then come home with a new 100 gallons to process while you are boiling the concentrate from the first 100 gallons.

Does your schedule change early in the season when it's freezing every night and some days vs. late in the season when it's warm at night and really warm during the day?

I know there are a lot of factors like the size of the RO, amount of sap, and boil rate. I just threw round numbers out as an example. I'm most interested in the schedule and timing of collection, to RO, to boil for people who work during the day.

Thanks,
Sean

[jmayerl]

I have owned both a 125 and now a 250. I can tell you that you need way more sap than that to start the RO. I would never run my RO without less than 275 gallons and the 250 requires at least 500 gallons to run. The reason is you must make enough permeate to run back through and rinse with. Ideally you run the sap through as soon as possible because the older the sap is the more bio film develops in the membranes and then it is thus harder to clean. If I know that I have enough sap to run with I will start the RO when I dump my first load from collecting, then when I get back with the last load a hour or so later the RO has concentrated enough to begin the evaporator. Then as I am getting up to full boil the RO is finishing. I will begin to rinse the RO when I have time during the boil. I generally finish boiling and rinsing about the same time(start to finish is 3-4 hours on average) remember that concentrate can not sit for more than a few hours. I will collect when I get home from work if necessary but that is 9pm.

[Chicopee Sap Shack]

What is the magic number in terms of gallons of raw sap to run a 100 ish or a 250 ish gallon RO as a minimum?


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[WESTVIRGINIAMAPLER]

I would start up my 500 for couple hundred gallons of sap if necessary. Only need couple hundred gallons of permeate to rinse after doing a soap wash daily. I usually carry over 200 to 300 gallons of permeate from last time I ran RO. It is not ideal to start up for 200 gallons, but if it is end of season and I need the syrup, I am not going to boil 200 gallons of raw sap and not going to dump sap. I know that is extreme and not too likely, but I wouldn't have any issue starting up a 125 with 100 gallons of sap.

[maple flats]

Nor would I have any problem starting the RO with less than an hour's worth of sap as long as the concentrate will be able to be boiled at once. If you have a 125 it will process 125 gal on average in an hour, removing about 75% of the water if run at the right pressure. If it is your first boil of the season and the pans are empty I would be careful. For example, if your pan holds 20 gal at boiling depth and boils away 15 gal/hr. you might be in trouble. If you have 100 gal of sap and remove 75% of the water, you only end up with 25 gal to boil. With the RO running, start the boil as soon as you have enough depth in the pan to boil and have about 30 minutes reserve to add. Then start the boil and continue ROing the rest. You now have 2 things to watch, the pan and the RO. As soon as you finish running the RO, just flush the membrane with permeate into the concentrate for 4 -5 minutes, then put 8-10 gal of hot water (permeate) at about 120 degrees in the wash tank and set to recirculate thru the membrane and back into the wash tank, (nothing but permeate). Have the pressure set so you get about the same flow permeate as concentrate according to the flow meters, but both return to the wash tank. Run for about 10 minutes. Then stop and set permeate to go to your permeate tank and concentrate to go to drain. When the wash tank is empty shut off the RO. Then draw cold permeate and run for for 5 minutes or more, returning permeate discharge to your permeate tank and sending concentrate discharge to drain.
While you were doing this, keep an eye on the pans, add wood as your routine schedule calls for and watch the temp. near the draw off valve. At a first boil you will not get a draw off because you had too little sap to begin with. Just make sure you boil all the concentrate at full boil for at least 10 minutes before you shut off for the night. Once you are used to both your evaporator and the RO, this will all take less than 2 hrs start to finish. In the learning stages you may want to double your fueling time intervals while you clean the RO, then go back to your normal routine to finish for the night. If you are used to the evaporator, you should know how much sap (concentrate) you need to carry you thru the cool down process, but if you run out and the boil is still rolling just use some permeate, but don't add too much.
For example, on my 3x8 I need 30 gal of concentrate to maintain the depth during cool down so I have a mark on a site gauge to my head tank. When the level gets to 30, I stop adding wood.
If this situation happened mid season, you will also need to account for the syrup you will draw off (that happens to be in my 30 gal minimum.)

[Clinkis]

I usually collect when I get home from work around 5 and as long as I get 100 gallons (which is about average for me) I fire up the RO. I process 50 gallons at a time and by recirculating I remove about 80% of the water, which takes about an hour, then fire up the evaporator with the concentrate and start the last 50 gallons through the RO. My evaporator only does about 10 gph so it works out about right. So 3 hours from the time I fire up the RO I'm done for the night. Without the RO I would be 10 hours running the same amount of raw sap through the evaporator.

[PerryFamily]

I start my RO when the first load of sap hits the tank, usually 1100 gallons. I set it to recirculate back into the raw tank. I run low pressure during this. When the second load hits, another 1100 gallons I run the pressure up and send it to the feed tank. As soon as there's enough in the feed tank I start boiling. Now I'm pretty much doing both until the end of the night. Usually there's another load, sometimes 2 that come in during boiling. It worked good for me. I now have a 1200 gph RO so I'm hoping I can eliminate the recirculating part. I had a 600 gph unit last year

[BreezyHill]

As soon as we have at least 200 G of sap and it is running the RO gets fired up by either the wife, one of the sons or I will if I am on the farm. She gets set to automatic Run setting. Son in high school gets home around 2:30-3 and will start boiling when there is enough to fire up the rig. Then we boil til the tanks are empty.

[SeanD]

Thanks for sharing that info. With my taps at different properties, collection time is a major factor in deciding how and where to expand. This has all been really helpful in thinking about how I can plan out adding more taps and collection time without losing on the boiling time.

Thanks,
Sean