Summarized list of DIY/alternative biopellets

Acrotrdco

Acrotrdco

New member
It seems like everyone is scrambling to find alternative / DIY biopellets that's cheaper than the commercial products, I've done some research and here's a summary of what've been found so far:

Polyhydroxyalkanoate (PHA):

Information:
Speculated to be the main component of commercial NP Biopellets (Reference #1).

PRO:
- Many successful cases using PHA (NP Biopellets) in controlling NO3/PO4.

CON:
- Expensive, about $99 per 1000mL of commercial NP Biopellets.
- Very hard to find sources of PHA except commercial products, which is expensive.

Polycaprolactone (PCL):

Information:
Confirmed to be the main component of Instant Ocean's Nitrate Reducer.

Reefers here on RC using PCL:
http://www.reefcentral.com/forums/showthread.php?t=1830864
http://www.reefcentral.com/forums/showthread.php?t=1766100
http://www.reefcentral.com/forums/showthread.php?p=17382991

PRO:
- Completely bio-degradable by bacteria, and provide a carbon source similar to PHA. (Reference #1)
- Some commercial biopellets for reef aquarium are also using PCL. (Reference #1)
- Less expensive compared to PHA, many alternative products can be found, such as "Friendly Plastic Pellets".
- PCL pellets can be bought for about $22-30 per 1kg from various internet sites, even from China.

CON:
- Compared to PHA, there's still very limited information on how successful PCL can control NO3/PO4 in reef aquariums
(If any of you have successfully controlled NO3/PO4 using PLA as biopellet alternative, please share your story with us!)

Polylactic Acid (PLA):

Information:
Basically these are degradable plastic (polymers) derived from corn starch and sugercanes. (Reference #2)

In fact we've a reefer here on RC who'd DIY'ing these polymers from corn starch. (Reference #3)

Studies on waste water processing have shown that PLA with corn starch at 10% weight content receive the best nitrate reduction effects. (Reference #1)

PRO:
- Commercial PLA are relatively cheap.
- Can be DIY from corn starch with some effort.

CON:
- Slow decomposition rate (Reference #4), meaning it could take just too long for the starch to be released from the polymer form into the water.
- Not much information on how effective PLA can be use to control NO3/PO4 in reef aquariums.
(Again please share your story with us if you've successfully used PLA as alternative biopellets)

Granular starch (rice, wheat and corn):

Information:

Just the everyday grain that you consume in meals.

Referring to PLA above, the optimal % of weight content of starch to be used is about 10%, meaning if you were putting in 100g of commercial biopellets in your reef system, you should be using 10g of granular starch or else you could be overdosing carbon source.

Reefers here on RC using granular starch:
http://www.reefcentral.com/forums/showthread.php?t=1874551
http://www.reefcentral.com/forums/showthread.php?t=1878307

PRO:
- They're CHEAP and readily available in grocery stores.
- Studies showed that granular starches are proven means to provide carbon source for denitrification in waste water processing as well as recirculating aquaculture systems (RAS).

CON:
- Unknown effect on minerials released into water column.
- Relatively high phosphrous content that could shift towards a Nitrogen limited environment.
- Inconsistant rate of decompose means it could release too much carbon into the water.

=======================================================================================

Sources and References:
1. Information on PCL, PHA and PLA (a very good read, recommended)
http://www.wamas.org/forums/topic/37366-diy-biopellets/page__st__25

2. PLA
http://en.wikipedia.org/wiki/Polylactic_acid

3. DIY corn starch polymer
http://www.reefcentral.com/forums/showthread.php?t=1780922

4. PLA decomposition rate
http://www.smithsonianmag.com/science-nature/plastic.html?c=y&page=1

5. Vinegar polymer encapsulation (have anyone even tried this?)
http://web1.reefcentral.com/forums/showthread.php?p=16572578
 
Great writeup. My tank is that PCL thread referenced here. It's quite effective, but I also run a mudbed refugium.

I've actually stopped using the IO brand PCL for the last month to see if there is a difference in water quality. N/P still undetectable. Skimmate has gotten lighter colored. Corals are still growing and look good.

Nuisance algae has cropped up a tid bit, just a little GHA and some RTA (red turf algae).
 
The manufacturers keep their active ingredients a top secret. The only one we know for sure is that Instant Oceans's product uses a PCL. The others are pure speculation at this point. It is speculated that the BP Biopellets are made of a PHA. FWIW, there are different chemical forms of all these categories of biopolymers.

The fact that PHAs are formed naturally in bacterial cytoplasm as an energy storage mechanism may make them the most attractive. PCL which is being used in the medical profession for sutures and what have you, which brake down in the body, may make PCL a close 2nd. The PLAs are interesting as well, since they are much cheaper to produce incorporating the bran of corn, rice & other plant materials into the molecule. The starch part may be beneficial since many experiments have shown the rate of nitrate brake down can increase with the additional starch. The other side is that starch may have negative effects on many coral & other organisms in a reef tank.

The bottom line may be the cost of the biopolymers and how easily we can get them. As demand increases for these biopolymers, the price will most likely drop. Currently they are expensive to produce and need to be shipped in from foreign countries like China which drives the costs up. :)

Different species of bacteria utilize these biopolymers more effectively than others as far as reducing nitrate and phosphate. So this is a variable we can't determine when trying to compare the different products available. The use of aerobic & anaerobic bacteria can produce different results for nitrate and phosphate reduction. A combination of both anaerobic and aerobic bacteria seem to produce the best results. This leads to questions regarding flow rates, the amount of product used & available surface area on the pellets as to what may be the most effect way to brake down the nitrate and phosphate. FWIW, most tests completed in aquarium environments have used these biopellets in sand beds and achieved good results as long as they are replaced about every 6 months. This may have advantages since the sand itself is used to form additional space for bacterial bio-films to develop. In the tests completed they found that a mixed sand bed with more porosity provided the best results. Perhaps a combination of using the sand bed technique as well as the reactor may provide the best results. A lot a questions in my mind as to how we implement the use of these various biopolymers. There have been studies in waste water where providing additional acetate has greatly benefited the brake down of the polymers which incorporate starch in the molecule.
 
HighlandReefer said:
... FWIW, most tests completed in aquarium environments have used these biopellets in sand beds and achieved good results as long as they are replaced about every 6 months. This may have advantages since the sand itself is used to form additional space for bacterial bio-films to develop. In the tests completed they found that a mixed sand bed with more porosity provided the best results. Perhaps a combination of using the sand bed technique as well as the reactor may provide the best results. A lot a questions in my mind as to how we implement the use of these various biopolymers. There have been studies in waste water where providing additional acetate has greatly benefited the brake down of the polymers which incorporate starch in the molecule.
Click to expand...

I wonder two things... for starters, what if we jammed pellets of PCL or PHA into the sandbed? Would that work? Also does this back up the theory behind of the IO Nitrate Reducer? In my experience with it, it swirls around in the tank until it settles into the sandbed and little crevices in live rock.

And another question, really how effective are solid OCD methods at reducing phosphate? If i'm running a reactor with GFO, could I really just toss it and go with solid OCD?
 
thebanker said:
I wonder two things... for starters, what if we jammed pellets of PCL or PHA into the sandbed? Would that work? Also does this back up the theory behind of the IO Nitrate Reducer? In my experience with it, it swirls around in the tank until it settles into the sandbed and little crevices in live rock.

And another question, really how effective are solid OCD methods at reducing phosphate? If i'm running a reactor with GFO, could I really just toss it and go with solid OCD?
Click to expand...


The sand bed Cliff said probably isn't those we have in aquariums, it's referred to moving bed bio-filters (MBB), correct me Cliff if I'm wrong.

Try to google that and RAS (recirculating aquaculture systems)
 
"The rate of marine biodegradation of PCL has been studied by Janik et. al. (1988) by measuring the tensile strength and percent weight loss over time in both seawater and a buffered salt solution. It was found that the weight loss, as a percent of total weight, decreased more rapidly in seawater than in the buffered salt solution. After eight weeks, the PCL in seawater was completely decomposed, whereas that in salt solution had lost only 20% of its weight. The same trend was seen for the tensile strength, where after eight weeks, the PCL in seawater was destroyed and that in buffered salt solution had decreased to roughly one-sixth its original value. It is therefore apparent that enzymes in the seawater solution assist to accelerate the biodegradation of PCL and other biodegradable plastics"
 
"PHAs are biodegradable via composting. Optimum conditions for the commercially available BiopolTM (PHA) degradation during a 10-week composting period were 60°C, 55% moisture, and C:N ratio of 18:1. BiopolTM reached close to a 100% degradation rate under these composting conditions. The aliphatic polyesters function like starch or cellulose to produce non-humic substances such as CO2 and methane. These aliphatic polymers are suited to applications with short usage and high degradation rate requirements (Gallagher, 2001).
 
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And about PLA

PLA is fully biodegradable when composted in a large-scale operation with temperatures of 60°C and above. The first stage of degradation of PLA (two weeks) is via hydrolysis to water soluble compounds and lactic acid. Rapid metabolisation of these products into CO2, water and biomass by a variety of micro-organisms occurs after hydrolysis.

PLA does not biodegrade readily at temperatures less than 60°C due to its 'glass transition' temperature being close to 60°C.
 
thebanker said:
I wonder two things... for starters, what if we jammed pellets of PCL or PHA into the sandbed? Would that work? Also does this back up the theory behind of the IO Nitrate Reducer? In my experience with it, it swirls around in the tank until it settles into the sandbed and little crevices in live rock.

And another question, really how effective are solid OCD methods at reducing phosphate? If i'm running a reactor with GFO, could I really just toss it and go with solid OCD?
Click to expand...



The PCL seems to work better when mixed into coarse sand beds of aquariums, as described in the Instant Ocean Patent:
Crushed coral substrates may be the best for nitrate reduction. Mixed sand beds do get good results. Fine sand does not do well. :)


Denitrification of aquarium water
http://www.freepatentsonline.com/7244358.html

From it:

However, surprisingly, it was found that PCL in the bottom degrades nitrate all the more effectively the more coarse-grained the bottom layer is made.

In a comparative test, 70 g PCL granulated material (round to oval balls, diameter of about 4 mm, content >99% polycaprolactone) per 100 l aquarium water were mixed in aquariums with 10 to 20 l bottom matter consisting of


a) sand (<1 mm)
b) fine gravel (ø 1-2 mm)
c) medium coarse gravel (ø 2-3 mm)
and the increase in nitrate of the aquarium occupied by fish and fed daily was measured over a period of 3 months.

An Aquarium Not Treated with PCL was Used as a Comparison.

The following gradation of the test results according to the prior art was suprising and an opposite trend would have been expected:


a) Sand (ø 1 mm)
The nitrate content increased in the control aquarium in the test period from 49 mg/l to 128 mg/l; only a low decrease in nitrates was found in the aquarium treated with PCL. The nitrate increased from 49 mg/l to 109 mg/l.
b) Fine gravel (ø 1-2 mm)
The nitrate degradation was considerably more intense.
The nitrate concentration increased from 49 mg/l at the start to 74 mg/l, in the control test to 135 mg/l.
c) Medium coarse gravel (ø 2-3 mm)
In this case, the nitrate reduction was even more clearly pronounced:
From 49 mg/l at the start, a decrease in nitrate to only 40 mg/l could even be seen; in the control test, an increase to 136 mg/l.

A further experiment with gravel having a particle size of 3-5 mm resulted in a nitrate increase of 18 mg/l at the start to 33 mg/l after 3 months, while the control exhibited the following nitrate concentrations: 18 mg/l to 104 mg/l. The resultant nitrate concentration was still under the value for medium coarse gravel (ø 2-3 mm).

In contrast to the control aquariums not treated in which the nitrate content increased further, the nitrate content remained constant in the PCL-treated aquariums after about 2-3 months, at a level dependent on the PCL dosage.

If PCL granulated material of about 4 mm in diameter are mixed in fine (ø 1-2 mm), even better in medium coarse (ø 2-3 mm) or even coarse gravel (ø 3-5 mm), the following nitrate concentrations set in in the treated aquariums, dependent on the bottom layer mixture, with various PCL dosages in the period of 3 months:


1) Various types of bottom mixtures, PCL dosage: 70 g/100 l water:
a) sand (ø<1 mm)—increase from 49 to 109 mg/l NO 3
b) fine gravel (ø 1-2 mm) increase from 49 to 74 mg/l NO 3
c) medium coarse gravel (ø 2-3 mm)—constant until decline in the range 47 over 27 to 40 mg/l NO 3 −
d) coarse gravel (ø 3-5 mm)—increase from 18 to 33 mg/l NO 3 −
2. Coarse gravel (ø 3-5 mm) with various PCL dosages after 3 months:
a) 0 g/100 l PCL: increase from 18 mg/l to 104 mg/l NO 3 −
b) 25 g/100 l PCL: increase from 18 mg/l to 86 mg/l NO 3 −
c) 50 g/100 l PCL: increase from 18 mg/l to 60 mg/l NO 3 −
d) 100 g/100 l PCL: reduction from 18 mg/l to 8 mg/l NO 3 −

Referring to FIG. 1, the process according to the invention for nitrate limiting, control and reduction by mixing PCL granulated material 10 with fine to coarse gravel 12 can be carried out very easily by simply mixing the PCL granulated material in the bottom mixture of the aquarium system 20 .

The application only has to be repeated every 6-12 months. It acts advantageously on the water quality, that anaerobic conditions in the coarse-grained bottom layer mixture that is thoroughly flowed through by water are not required and are also not produced by the process. As a result, anaerobic decomposition processes and the H 2 S release by sulfate reduction can be avoided.
 
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That's interesting. I didn't read through the entire patent journal, but I'm wondering if there is a positive effect from PCL settling into holes in live rock & getting lodged in filter sponges. I would think: yes, there is, since both applications are analagous to being lodged in a gravel bed.

Then again, this test uses round oval balls ~4mm, and the commercially available IO PCL is closer to the size of lead shot. I wish the guy using the DIY Friendly Plastic was able to keep the experiment going.
 
Acrotrdco said:
The sand bed Cliff said probably isn't those we have in aquariums, it's referred to moving bed bio-filters (MBB), correct me Cliff if I'm wrong.

Try to google that and RAS (recirculating aquaculture systems)
Click to expand...

Acro are you referring to a fluidized bed? Because that's the same as an upflow reactor... we know that works.
 
Thanks for that link. I'm going to check my local forum for PCL group buys. I like the rice idea that's been going around, but inconsistent rates of decomposition have me fearing for potential bacterial blooms and O2 deprivation spikes.
 
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