Biofilm problem
1:17 pm in environmental impact, International, made from scratch (without a kit), Materials and Resources, Nutrients, posts with pitcures!, Projects in Process, questions, Seeking Advice, Uncategorized by Juan David Garavito
Hi this is my first post here. Sorry for my english, but i need your help.
i’ve been running my own windowfarm for at least 3 months and now i have a tasty lettuce.
But right now i’m concerned about the bacterial colonies growing on all the airlift tube.
Biofilms growing on the tube
Since i’m a microbiologist, i know the health risk related on having biofilms on food supplies and related surfaces, so i need to avoid them in next trials and change the tube system. i dont know if this are benefical bacteria, but if they are forming biofilms, they could make in the bottom the perfect habitat for facultative anaerobes like E.coli and Salmonella
i think the tube material could be related to the huge ammount of bacteria attached to the tube walls.
i can try to add natural disinfectant previously but i think this won’t resolve the problem in long term.
Does anybody have the same problem? any idea?
I am not an expert, but you should try using black tubes instead of clear tubes.
The two solutions I’ve come across on this site (almost done building my own WF) are:
1) Use tubes that don’t allow light in (black tubes)
2) Clean tubes regularly
a) I’ve heard that the bead chain(http://www.somethingaboutsilver.com/wp-content/uploads/2012/01/SIlverBeadChain.png) used in the “official” WF make a good cleaner by attaching it to a string and dragging it through the air tubes.
I was trying to find/design a system that used capillary action to move the water up the column but I’m not even sure it’s possible. That would be one solution.
Maybe if there are types of tubing that won’t allow biofilms to form like you suggest – probably costs more money though.
I’m sure the lettuce farmers grow (hydro or soil) must have some small percentage of a lot of bacteria, good and bad? You wouldn’t happen to know would you?
CG
That looks pretty nasty alright! We have clear tubes on our new window farm and there is a distinct green algea growth starting in there – but it is quite bright green, unlike yours! I don’t know what the exact material of the tubes are, but would definitely consider black tubes next.
Can you take a swab of it and grow it in a petri dish and microscope it? That would be cool
Also – your lettuce leaves look pretty pale green side and leggy – is the plant getting enough light/nutrients?
Hi,
probably is it a material problem. I don’t use silicon tubes ( like in aquariums) Silicon growth up fungi and so on. Often you can see this in bathrooms with silicon between tile. My tubes are PVDF and since January I have a very little bit alga in it. See my construction below. … and my tubes are in aluminium pipes.
Greetings
JKDF
http://our.windowfarms.org/2012/01/23/windowfarm-as-mobile-tower-v1-0/
I am using silicon tubes and I have pritty much the same problem. Avoiding light is one option, but I guess this wouldn’t solve the problem – you just don’t see it any more…
Unless you’re using animal derived nutrients you shouldn’t have any e.coli or salmonella issues. I’d say clean it out and paint it or replace with opaque material.
hi. thanks all for your responses.
Chris: 1. you should look for wick irrigation on google and you can find related info about capillary systems that may help you, but on those systems its hard to provide the nutrients properly, and only works for water irrigation with highly soluble nutrients so it’s difficult with colloidal nutrients commonly found on organic sources like compost tea nutrient solution. Dont forget to use nylon wick or fabric, never use cotton because its biodegradable.
2. i have dismounted my WF system and i realize that the biofilm only grew on the tubes, for example the bottle inner walls doesn’t have biofilm on it, so i concluded that the cause is the tube material.
Lauren: 1. yeah! it looks very nasty on all the tube, in fact the worse part was the lower part of the tube linked to water reservoir.
2. unfortunately i don’t have enough light on my kitchen window, so my lettuce took 1 month more to grow and is a little bit pale green. Today i ate the lettuce and was tasty. I cleaned the lettuce very well obviously.
Painting the tubes or replacing it with opaque material doesn’t solve the problem, only hide it. most of bacterias don’t need the light to grow, so this solution only works for cyanobacterias and algae because they need to do photosyntesis. I think this could help a little but the most important way to prevent is choosing the right material for the tube, and having an arrange with short tubes linked together to facilitate cleaning.
any idea with cheap tube materials i can use?, i think that here on Bogotá could be really hard to find PVDF tubes and probably they would be expensive.
Thanks for the tip.
I was curious if the “wicked” water could carry the dissolved ions – seems like it’d be messy/inefficient. In my head I guess I envisioned small silicon/glass tubes that would move the solvent up the tube just for fun. Kinda like TLC blotters (if you ever had to use those in lab). I feel like tubing is the way to go, though, for simplicity’s sake.
” i have dismounted my WF system and i realize that the biofilm only grew on the tubes, for example the bottle inner walls doesn’t have biofilm on it”
Are you sure the microbes would still grow *significantly* without light? It may be that the inner walls don’t get any light so they aren’t growing there and not the material. Maybe cover some tube with opaque tape and run it through some nutrients for a while and then remove the tape to check (don’t forget a control
)
Are you using a compost tea or just a straight nutrient solution?
CG
Also I wonder if the plant would die before fruiting if a significant pathogenic infection occurred. lol, they seem well equipped with an immune system:
http://www.nature.com/nature/journal/v444/n7117/full/nature05286.html
when you have those bacteria in your wndowfarm which is dripping water over your plants half the time for the last three months inside your kitchen I think you will have ingested these bacteria already and your imume system already knows how to deal with them – Just my 2 cents
@Juan David Garavito – What makes you think that growth is bacterial and not just algae? Since you are a microbiologist, can you take it to the lab and test it?
EXCELLENT REMINDER TO EVERYONE TO USE FOOD SAFE MATERIALS IF YOU ARE GOING TO DIVERGE FROM THE INSTRUCTIONS!!
LET’S ALSO DO A BIOLOGY REFRESHER AND REMIND EVERYONE THAT THIS COMMUNITY IS ABOUT RESEARCH, WHICH ENTAILS RISK.
1_ Get tubing that is designed for food safe use. I really can’t emphasize this enough. The material may be slightly more expensive but your health is what is at stake. This is the reason we selected the PETG tubes you can get in the instructions. They do not leach any harmful materials and they are food safe. There are tons of tubes made for food safe applications. Think about all of the machines that dispense soda at every fast food store around the globe. There are hundreds of thousands of different sizes, shapes, materials, price points and durometers of tubing for food safe applications that are engineered to prevent bacterial growth. There is no reason to compromise on cost with something that is not food grade.
2_ Definitely clean your tubes. That is part of a normal maintenance routine. I’m not sure how you would clean the flexible tubing you are using but with the rigid tubing, you just take a sufficient length of bead chain with a bead chain connector on the end and thread a mop fiber through the connector. Tie it in a bow. Then drop the chain down the rigid tube and pull it through. We do this several times and use a light dishsoap solution.
3_ Don’t confuse algae and bacteria. Two completely different branches of the tree of Life. Algae growth is common in all hydroponic systems and is perfectly safe. In fact, many organic nutrients are made from seaweed, which is just giant algae and is one of the most rich and diverse nutrient sources for plant life. If you are ever concerned about a growth in your system, send it to your local county agricultural lab or the Cornel Agricultural Extension office for testing. It costs between $5 and $30.
4_ The only time we have found bacteria was when we tried using an antifungal oxidant on one of the giant installations. When it appeared, we did controlled testing on the columns and found that as soon as we stopped using the oxidant, the bacterial colony went away. It was not a harmful bacteria. It turned out to be a strain related to those in our stomachs.
5_ Fertilizers and nutrient solutions that contain animal products may contain more risk. These are reasons why industrial agriculture only uses synthetic nutrients that they can cook up in a test tube, to eliminate any uncertainty. There are downsides to that approach as well, namely insufficient nutrients being delivered to the plant’s eater. This is why we need as a society to learn and experiment. It is risky to experiment, but ultimately it leads to a better world for the future.
hey, thanks for your responses. i had been out for a while.
@sequencegeek 1. You can use this kind of tubes for capillary use too, but i still prefer wicks because they don’t plug. you can also use the same substrate as well to wick the solution. http://img.directindustry.es/images_di/photo-g/tubo-capilar-para-difraccion-de-rayo-x-491667.jpg
2. Yes I’m sure that microbes will still grow without light, for example most of bacteria live deep in soil without any source of light. How do I’m sure that the cause is the tube material? In the inner bottle i have the light too, because I left a tape space to check water level. in addition i put the same tube inside the bottle with an air stone for aireation purposes, it result on huge amount of biofilm on the tube surface, but nothing on the PET bottle inner walls.
3. Yes, plants have immune system, based on chemical an physical responses. but also they get help from microbes too. for example when you use compost tea regularly, loaded with beneficial microorganisms, they occupy the plant injury sites before, preventing the arrival of bad guys. some of them produce antibiotics to help plant fighting the infection, other like the fungi Thrichoderma depredates disease causing fungi.
4. I’m not using compost tea, but I’m planning to move from hydroponics to bioponics, using organic sources like fermented compost or worm casting. so that’s why i want to avoid biofilms.
@Bram: i ate my lettuce, and probable i ate bacteria with it too. Nothing happened to me fortunately. but it could do in the future. Bacteria trapped in the biofilm can be well protected from active compounds used for cleaning, especially in the presence of fatty deposits. The pathogens are of particular concern, since the biofilm may facilitate its spread on surfaces and their transfer to the plant. Several studies have shown that these cells appear to be more resistant to disinfectants. Here is more info about biofilms and their risks. its a good article http://bacteriality.com/2008/05/26/biofilm/
@admin
1. completely agree with you.
2. Cleaning its vital. I made a mistake using one piece large tube, because its really hard to clean, so I would recommend using short tubes connected each other through all the airlift system .
3. I have been working with bacteria in the past 5 years, i know how to recognize them. There are differences in the way the grow. most of the time you see first a tiny white, cream, or yellow dot which means a bacterial or yeast colony growing on this spot, in algae most of the time is green. Then this tiny dot begins to increase his size in a radial way. with time it can fuse with near colonies. As they die, they turn to brown which means they are being oxidized. Bacterias grow faster than algae, you have big dots on 24 – 48 hours. But this is not always the rule. Unfortunately I’m not working in lab right now and don’t have microscope, or determinative microbiology test, so its difficult to me being totally sure.
4. Having bacteria on your hydroponic system not always means bad things. In fact we need them in our system because they promote plant growing and produce phytohormones like auxins, other can fix nitrogen from the air like Azotobacter, Rhizobium, other produce acid that breaks inorganic phosphates releasing the phosphorous for the plant.
The real problem occurs when they set their home on unreachable sites like the tubes and it’s hard to clean the biofilms on it, creating “dead zones” you can’t control. You can create a controlled habitat for them on the substrate, specially the porous ones like coco hair, coco coir and expanded clay pellets, closer to roots to help plant growth. Don’t forget: You must promote bacterial and fungi growth on your system!.
5. We need to move towards organic hydroponic, commonly called Bioponics. Using chemical salts could be expensive in the future, and it’s not totally friendly with the environment. Unluckily only one company provides organic nutrient solutions: “General Hydroponics” with his brand “BioSevia” . For me, a guy in Colombia, it’s too expensive import those solutions from Europe or America, so I need to make my own with locally sourced materials and is in what I’m working right now. So Compost tea it’s the key. Some Japanese scientist made organic nutrient solution on 2011 using the Compost tea principle and mineralization of organic nutrients. But you need good compost first to make good compost tea because the have more nutrients. also pathogens in compost are killed on thermal phase of process when temperature reach 65ºC, so the animal source risk excuse it’s not a problem anymore.
I learned a lot from this topic. thanks for all your inputs sirs/mam.
if you are concerned about e coli and anaerobic bacteria you can add an airstone to the reservoir to keep the solution aerobic. there will still be a problem with the clear tubes and biofilm in them.