Principles of Biological Nutrient Removal (1)

1/Biological Nitrogen removal

• Biological nitrogen removal requires a two-step process. In the first step ammonia is oxidized to nitrate (nitrification) and various process configurations are then employed to provide the nitrate as an electron acceptor for biological respiration so that it can be reduced to molecular nitrogen (denitrification). Fundamental considerations will be presented first for the nitrification step in nitrogen removal. Included in this review are the microbiology, basic biochemical reactions, biological kinetics, and the factors that affect the kinetics and performance of biological nitrification and denitrification reactions

2/BIOLOGICAL NITRIFICATION

2.1.Microbiology

• Early work by Schloesing and Muntz (1877) investigating the percolation of sewage through a sand column found that the conversion of ammonia to nitrate and nitrite was due to living organisms, since the reaction could be stopped by introducing chloroform vapor into the column. Classical experiments by Winogradsky (1890) led to the isolation of autotrophic nitrifying bacteria, Nitrosomonas and Nitrobacter, which oxidize ammonia sequentially to nitrite and then to nitrate, respectively. Painter (1970) has listed other autotrophic bacteria genera capable of obtaining energy from the oxidation of ammonia, Nitrosococcus, Nitrospira, Nitrosocyctis and Nitrosoglea, and nitrite, Nitrocystis, but the nitrification in soil or wastewater treatment processes is attributed primarily to Nitrosomonas and Nitrobacter.

• Painter (1970) summarizes other literature sources that show a large number or heterotrophic bacteria capable of forming nitrite or nitrate. In one study by Eylar and Schmidt (1959) of about 1000 heterotrophic organisms isolated from soil, only fifteen wrere found to be able to nitrify. A review by Focht and Chang (1975) indicated that heterotrophic nitrification is possible with diverse genera of bacteria, fungi, and actinomycetes. However, it is doubtful that significant quantities of nitrate are generated by heterotrophic organisms, since autorophic nitrification rates are about ten times greater. Heterotrophic nitrification may be more prominent in atypical environments with either very alkaline or acidic pH conditions.

• Bock et al. (1988) reported on the ability of Nitrobacter to grow and reduced nitrate while using acetate, formate, pyruvate, or glycerine as organic substrates. They further showed in an aerobic/anoxic conditions. This observation has not been studied in wastewater treatment.

2.2.Oxidation and Synthesis relationships

The energy-yielding two-step oxidation of ammonia to nitrate is generally accepted to be as follows:

• Nitrosomonas

2NH4+ + 3O2 → 2NO2- + 4H+ +2H2O

• Nitrobacter

2NO2- + O2 → 2NO3-

• Total reaction

NH4+ + 2O2 → NO3- + 2H+ + H2O

• The standard free energy release associated with ammonia oxidation has been estimated to be 66 to 84 kcal/mole of ammonia, and for nitrite oxiation it has been estimated to be 17.5 kcal/mole of nitrite (Painter, 1970). If the amount of cell prodcution is proportional to the energy released, a greater amount of biomass should be formed from the oxidation of ammonia to nitrite than from the oxidation of nitrite to nitrate.

• Based on the above, the oxygen required for complete oxidation of ammonia is 4.57 g/g N oxidized with 3.43 g/g used for nitrite production and 1.14 g/g used for nitrate production. The amount of oxygen required is less than 4.57 g/g N when synthesis is considered in addition to oxidation due to oxygen obtained from fixation of carbon dioxide and nitrogen into cell mass. Wezernak and Gannon (1967) found that the actual total oxygen consumption was 4.33 g/g N with 3.22 g/g N used for ammonia oxidation and 1.11 g/g N used for nitrite oxidation. The following equation, presented in the U.S.EPA Nitrogen Control Manual (1975), accounts for both synthesis and oxidation and shows an oxygen requirement of 4.2 g/g N. The equation was developed using cell yield coefficients of 0.15 g/g NH4-N oxidized and 0.02 g/g NO2-N oxidized

NH4+ + 1.83O2 + 1.98HCO3- → 0.21C5H7O2N + 0.98NO3-+1.041H2O + 1.88H2CO3

• For activated sludge designs employing nitrification, a single yield coefficient that includes the growth of both Nitrosomonas and Nitrobacter is more convenient and some of the more recently used values.

How to make BIODIESEL (part 5)

1/Acid-stage questions

• A question will probably arise: why not mix the methanol with the sulphuric acid before adding them to the oil/fats? Two major reasons: (a) the reaction between methanol and concentrated H2SO4 is quite violent and it could splash, which doesn't happen if you mix it as described; and (b) dimethyl ether can form. Mixing alcohols with concentrated H2SO4 is a way to dry the alcohols (which is good) and also a way to make di-alcohol ethers, not good: dimethyl ether is a gas, colourless and highly explosive.

2/Base-stage questions

• The second-stage product should be quite murky. This is no problem, as it will wash out.
  After the processed oil/fat has turned straw-yellow (step 16), you've let it settle for an hour and drained the glycerine, you should have a total of about 120 ml of glycerine per litre of oil/fat used. If it's less than about 100 ml/litre oil, something's wrong, even if the colour is right -- the process hasn't gone far enough.

• This will almost certainly be due to carbonated lye. Lye has a really limited shelf life: CO2 from the air neutralizes it and forms sodium carbonate. Carbonated lye is much whiter than pure lye, which is almost translucent. The carbonate in the lye won't harm the reaction, but you'll have to use more lye.

• The solution: Repeat the procedure from step 13. Prepare a fresh batch of methoxide with 0.03 litres of methanol and 0.75 grams of lye for each liter of oil/fat. Reheat the biodiesel to 55 deg C (131 deg F), add the fresh methoxide and mix as before. No need this time to remove glycerine during the processing as in step 15, and don't worry about the colour. Mix for one hour, settle, drain off the extra glycerine, and proceed from step 18.

• If you plan to continue using the carbonated lye, make sure to increase the amount by 25% next time you make biodiesel. Store lye at room temperature, in dry conditions if possible, with the container lid really tightly closed.

3/Methanol recovery (optional)

• To keep costs down, even amateur biodiesel producers try to salvage the unreacted methanol. There are two major methods to do this: heat extraction and vacuum/heat extraction.
  

*Heat extraction

• Heat the second-stage product to 70 deg C (158 deg F) in a sealed boiler/vessel and lead the fumes into a condenser. Intercept the condensed methanol in a liquid trap. Take great care because methanol is highly flammable and the fumes are explosive. The temperature will need to be increased as the amount of unreacted methanol in the mixturedecreases.
  

*Vacuum/heat extraction

• This is basically the same as heat extraction, but it requires less energy. The drawback of this method is that you need a special vessel and equipment to do this. A good example is Dale Scroggins's reactor:http://home.swbell.net/scrof/Biod_Proc.html
  When building your reactor it may be a good idea to take one step at a time. Build the reactor, get confident with the process and eventually upgrade to methanol recovery.

At least a quarter of the methanol used can be recovered -- ie, 50+ ml per litre of oil/fat. Mix it with fresh methanol for preparing the next batch of methoxide.

4/Quality

• Diesel engines require quality fuel. You just can't pour poor-quality biodiesel into the tank and expect the engine to go on and on without problems. You have three very dangerous enemies: free glycerine, poorly converted oils/fats and lye. Free glycerine and mono-, di- and triglycerids (poor ester conversion) will form gum-like deposits around injector tips and valve heads, lye can damage the injector pump. The key to good fuel is to just do it right and finish it! Use pure chemicals (sulphuric acid, sodium lye and methanol) and measure them accurately, and follow the instructions carefully -- this will take care of poor conversion. Proper washing will get rid of the glycerine and neutralize any remaining lye.

• There are also kits available for various quality tests. I was told in a letter from one of the visitors to our site of a test used by the motor industry for determination of glycol in motor oil. This should work for free glycerine determination.

• "For glycerine analysis I suggest that you get a test kit for determining ethylene glycol in motor oil. This test is simple and it generates a purple colour if substantial free glycerol is present. Just analyze the biodiesel as if it were motor oil. Used-car dealers use the test to determine if there are leaks in the cooling system. Glycol and glycerol give the same result in the test." (With thanks to Martin Reaney)

• Paper chromatography and thin layer chromatography will tell you the conversion rate, and titration may tell you about any remaining lye.

How to make BIODIESEL (part 4)

1/Second stage

This is the base-catalyzed stage.

• 13. Heat the mixture to 55 deg C (131 deg F) and maintain for the whole reaction.

• 14. Add the second half of the prepared sodium methoxide to the heated mixture and start mixing at the same low speed of not more than 500 to 600 rpm.TAKE CARE when handling the sodium methoxide -- full safety precautions!

• 15. Optional: If your reactor allows for it, start draining glycerine by-product from the bottom 20-25 minutes after the start of the base stage. (Pump-mixing works best for this -- with pump or mixer, turn the motor off for a few minutes if necessary to allow the glycerine to settle.) Repeat every 10 minutes -- take care, the glycerine is quite hot and caustic! Set aside -- see step 18.

• 16. All users: Take regular samples in a 1" to 1.5" diam. glass container. Watch for a straw yellow colour of the ester portion. Glycerine (brown and sticky) will settle at the bottom of the jar. When this colour is reached (usually in 1.5-2.5 hours) turn the heat and mixer off. Instead of taking out samples to check the colour you could use translucent braided tubing for the pump.

• 17. Allow to settle for one hour.

• 18. Optional: For easier washing: Drain off the glycerine. Measure off 25% of the total glycerine (including previously drained glycerine if you followed step 15) and mix with 10 millilitres of 10% phosphoric acid (H3PO4) for each litre of oil/fat processed. The mixing can be done with a wooden spoon in a plastic container. Pour the acidified glycerine back into the reactor and stir for 20 minutes, unheated. Allow to settle for at least six hours and then drain the glycerine fraction completely.

• ***THIS IS IT. During the first stage, free fatty acids were esterified and some triglycerids were transesterified. The base-catalyzed stage does only transesterification, but it's much quicker and more complete.

2/Washing

• 19. Use the bubblewash method, but no need to monitor pH anymore. Just add a little 10% phosphoric acid (H3PO4) to the washing water first, 10 millilitres per gallon (2-3 ml/litre), just to be on the safe side -- I don't want ANY lye floating around my fuel pump.If you are curious about the results of your wash, use ordinary litmus paper, it will tell you the rough pH level (acidity/alkalinity). The end result should be neutral (pH7) or just below neutral.

• 20. Use one-third the volume of water as the amount of biodiesel to be washed. Make sure both the water and biodiesel are roughly the same (room) temperature. Pour your biodiesel into the vessel with the water, throw in the aquarium stone and start the air pump. Let it bubble for 24 hours minimum. Turn the pump off and let the mixture settle for half an hour. The water will fall to the bottom, turning completely white, and the fuel you made will be much lighter in colour now. Drain the water, repeat the procedure two more times. Remove the biodiesel from the vessel, taking care not to get any water with it.

• 21. Let the biodiesel stand for about three weeks and use only when it becomes crystal clear; take a sample in a large marmalade jar and wait until it is completely cleared. Put it on your window shelf and enjoy looking at it while it clarifies. (If you want quicker results, heat the biodiesel to 45 deg C, 113 deg F, and let it cool.)

• **NOTE: A deposit may form in the bottom during settling -- don't let it get in your fuel tank!

*Note: source from © Copyright Aleksander Kac, 2001. Patents pending

How to make BIODIESEL (part 3)

1/Introduction

• To make biodiesel fuel efficiently from used vegetable oils and animal fats we have to avoid one major problem: soap formation. Soap is formed during base-catalyzed transesterification (using lye) when sodium ions combine with free fatty acids present in used (and some virgin) vegetable oils and animal fats. The soaps diminish the yield because they bond the methyl esters to water. The bonded esters get washed out at the washing stage but make water separation more difficult and increase water consumption. This process takes care of the free fatty acids.

• In one early test I used a mixture of 50% heavily used cooking oil and 50% pork lard. The result was a pure product with absolutely no trace of soap! The biodiesel looked nice, and smelt nice, as if made from virgin oil.

• This is a simple procedure. The first-stage process is not transesterification, but pure and simple ESTERIFICATION. Esterification is followed by transesterification, but under acid conditions it's much slower than under caustic conditions and it won't do a complete oil-to-methyl ester conversion as the reaction is much more equilibrium-sensitive. Without methanol recovery, the alcohol overdose required would make the price of your fuel jump, and even with recovery it would still be much more expensive. Hence the second base-stage.

• For the first stage you'll form a compound out of an acid and an alcohol. The alcohol is still methanol, but instead of using lye (sodium hydroxide), the CATALYST in this reaction is sulphuric acid ("battery acid"). It needs 95% sulphuric acid (battery acid is around 50%). Sulphuric acid is one of the commonest chemicals on Earth, just like lye. More concentrated sulphuric acid -- 98% and above -- costs more, but 95% works just fine if you follow these directions. Other acids won't work: it must be sulphuric acid. The second stage uses lye, as usual -- but it only uses about half as much as other methods.

• The sulfate ion in the sulphuric acid combines with the sodium ion in the lye during the second-stage reaction to form sodium sulphate, which is a water-soluble salt and is removed in the wash. No sulphur remains in the biodiesel fuel product.

2/Equipment

• You don't need a special processor for the Foolproof method. Generally, a bottom-drained reactor vessel is best, closed on top. Tall, narrow containers work better than wide, shallow ones. Use a circulating pump for mixing rather than a mechanical stirrer. The pump should take the mixture from near the bottom of the reactor and return it via the top, to splash down on the surface. For a 35-litre reactor, a 100-W washing-machine pump will do, along with a 1.5kW washing-machine immersion heater to heat the mixture (get a heater that's coated with stainless steel). You could use a thermostat to control the temperature, but they're expensive: just use a thermometer and switch on the heater as required.

• Ordinary iron and steel implements and containers will eventually corrode because of the acid used in this process. However, you can still use the usual 55-gal (200-litre) drum. The proportion of acid used in this process is very low -- you should be able to use an uncoated drum for a year or more before the rust gets out of control. I use a polypropylene plastic reaction vessel. Any plastic that won't deform at 100 deg C (212 deg F) or a bit more is fine. Stainless steel is also fine. Use an immersion heater with plastic containers. With steel containers you can use propane heaters to heat the oil, then switch to an immersion heater before adding the methanol.

3/Test batches

• Whenever you're trying a new method, it's always a good idea to make small test batches of a litre or less first to familiarize yourself with the process before moving on to bigger batches.
• Most people use kitchen blenders for this -- but don't use it for food again afterwards!

4/The process

1. Filter the used cooking oil first as usual.

2. For a successful reaction the oil must be free of water. Here are two methods of removing the water content:

• (a) Settling the water out: This method saves energy. Heat the oil to 60 deg C (140 deg F), maintain the temperature for 15 minutes and then pour the oil into a settling tank. Let it settle for at least 24 hours. Make sure you never empty the settling vessel more than 90%.
• (b) Boiling the water off: Less-preferred method as it uses more energy and helps to form more FFAs in the oil. Heat the oil to 100 deg C (212 deg F). As the heat rises water separates out and falls to the bottom -- drain it off to avoid steam explosions. Maintain the temperature until no more steam bubbles rise.

5/First stage

3. Measure the volume of oil/fats to be processed (preferably in litres).

4. Heat the oil to 35 deg C (95 deg F) -- make sure that all solid fats are melted.

5. Methanol: use only 99%+ pure methanol. Measure out the methanol -- 0.08 litres of methanol for each litre of oil/fats (8% by volume). Add the methanol to the heated oil.

6. Mix for five minutes -- the mixture will become murky because of solvent change (methanol is a polar compound, oil is strongly non-polar; a suspension will form).

7. For each litre of oil/fats add 1 millilitre of 95% sulphuric acid (H2SO4). Use a graduated eyedropper, a graduated syringe or a pipette. TAKE CARE when handling the concentrated sulphuric acid!

8. Mix gently at LOW rpm (don't splash!) while keeping the temperature at 35 deg C. The rotation of your stirrer should not exceed 500 to 600 rpm -- speed is not crucial and splashed oil is a mess to clean.

9. Maintain the temperature at 35 deg C for one hour then stop heating. Continue stirring.

10. Stir the unheated mixture for another hour, a total of two hours, then stop mixing. Let the mixture sit for at least eight hours, overnight is better.

11. In the meantime prepare the sodium methoxide: measure 0.12 litre of methanol for each litre of oil/fat (12% by volume) and weigh 3.1 grams (up to 3.5 grams if purity is in doubt) of sodium lye (sodium hydroxide, NaOH) per litre of oil/fat. Mix the lye into the methanol until the lye is completely dissolved.

-Sodium methoxide is a DANGEROUS CHEMICAL. Take full safety precautions when working with methanol, lye and sodium methoxide, wear safety goggles, protective gloves and clothing, have running water nearby.

**NOTE: This process uses only about half the usual amount of lye as there is less fat left to transesterify. Use 99%+ pure sodium hydroxide lye. After opening the container, close it again as quickly as possible to prevent moisture getting in. Weigh the lye carefully -- using too much will complicate the washing process later.

12. After settling for eight hours, or the next morning, pour half of the prepared methoxide into the unheated mixture and mix for five minutes. This will neutralize the sulphuric acid and boost the base catalysis. If you've used solid fat, it probably solidified during settling -- gently melt the mixture first.

Now you can continue with the normal procedure with the lye as the second stage.

TIMING FOR BIODIESEL PROCEDURE

TIMING

-Biodiesel typically takes a couple of days to a week from start to finish to make a batch. Most people making biodiesel make anywhere between 20 to 100 gallons at a time in a batch process.
Here's a breakdown of typical timing intervals from start to finish:

• START
• Collecting Oil - 1-2 hours
• Filtering Oil - 1-2 hours (depends on amount of oil)
• Titration Of Oil - 10-15 minutes
• Transferring Oil To Processor - 10-20 minutes
• Heating Oil - 1-4 hours (depends on amount of oil, voltage & wattage of element)
• Making Methoxide - 5-20 minutes (depends on amount of methanol and catalyst used)
• Mixing Methoxide Into Oil - 20-30 minutes
• Mixing Oil & Methoxide - 2-3 hours
• Settling Oil - 8-10 hours (usually overnight)
• Draining Glycerine - 5-10 minutes
• Transferring Biodiesel To Wash Tank - 10-20 minutes
• First Mist Wash - 2-3 hours
• Second Mist Wash - 2-3 hours
• First Bubble Wash - 6-8 hours (usually overnight)
• Second Bubble Wash - 6-8 hours (usually overnight)
• Transferring Biodiesel To Drying Containers - 10-20 minutes (depends on amount)
• Drying Biodiesel - 2 hours to 1 week (depends heavily on weather and amount made)
• Transferring To Storage Containers - 10-20 minutes (depends on amount)
• FINISH
  

How to make BIODIESEL (part 2)

1/Titration

-Before you are able to process the vegetable oil into biodiesel you have got to know first how much methanol and catalyst you need. As far as methanol is concerned you may always assume about 200-220 ml methanol per litre of oil. The percentage of NaOH is variable. If new vegetable oil is processed, then you will require 5 g per litre of oil to substitute all glycerol by methanol. If waste oil is used then the same amount of catalyst will be required plus a certain amount to neutralize the free fatty acids that are present in the oil. To this end you will have to determine by way of a test, called titration, how many of these free fatty acids (FFAs) are present in your oil.

*What do you need?

• 10 ml isopropyl alcohol, 99%*
• Oil (heated to 45º C)
• Phenolphtaleine-solution (0,2%-0,4%)*
• Catalyst (NaOH, KOH)*
• Distilled water
• Some glass saucers
• Some hypodermic syringes to enable dosing the right amount.*
• a pair of scales preferably accurate to 0.1 or 0.01 g.

2/The procedure is as follows

-Dissolve 1 g of catalyst in 1 liter of distilled water, this solution is the titrant. NaOH is very difficult to dissolve. This can best be done by putting for instance 50 ml distilled water into a transparent bottle, adding the gramme of NaOH, closing the bottle and shaking it as long as it takes to see no visible grains and pouring this back into the distilled water.
-This solution is suitable to carry out titrations in the following weeks. In order to reduce the chance of errors, you may consider dissolving 3 g of catalyst in 3 liters of distilled water. An error of for example 0.2 g has less effect that way than in the case of 1 liter. Cork the bottle and keep it well. Take care when weighing the grains of NaOH that you do not leave the packaging open. The grains are very quickly to attract water and will not be fit for use anymore. The photo on the right shows how the grains look when they are subjected to a few minutes of oxygen.

• Pour 10 ml Isopropyl Alcohol in a glass cup or saucer.

• Heat a bit of the oil to be tested to a temperature of 45º C , mix 1 ml of it with the alcohol and mix well, it will get a yellowish colour.

• The amount of alcohol does not require much precision, but it is important that you should measure out exactly 1 ml of oil. An old trick is to suck in a bubble of air first into the hypodermic and then the oil, this way you are able to read more precisely.

• Add 2-3 drops of PH-indicator solution (phenolphthalein).

-Start carefully to add the water with the catalyst, keep swinging the cup. The fluid will colour to a light pink, but will turn yellow again if you keep swinging. When the oil with alcohol remains pink for a period of 30 s, you stop adding the solution. Make a note of how many ml of solution you have used and repeat the whole procedure once or twice in order to make sure you have titrated correctly.

-When you have a PH-meter at your disposal you can use it instead of the phenolphtaleine-solution. When the fluid has reached a PH-value of 8.5, then you have added enough NaOH-solution.
That's all !!!!

-If you need less than 3 ml of the solution then you most probably have laid your hands on very good oil, 3-6 ml means that the oil is suitable to turn it into biodiesel. 6 ml or more implies a poor quality, but the oil may still be suitable for the production of biodiesel. Take care when titrating that you should use each instrument for only 1 agent. We advise to label all hypodermics, pipettes and other tools in order to avoid mistakes.

3/Test batch

-Irrespective of the titration results, it is advisable to first process one litter of oil, before turning to the production of bigger amounts. Should you have made a mistake somewhere than this will appear now, this way you avoid that you may have to throw away maybe 100+ litres of oil because you made a mistake in titration.
-Fortunately, one litre of test diesel is easy to make. You start with heating 1 litre of oil to 45°C, preferably in a jar or bottle that can be corked. In the meanwhile you mix 220 ml of methanol with the amount of catalyst you determined in titration. Put this in a glass jar or bottle that can be corked well. This mix is called methoxide.

4/How much NaOH?

-In processing new oil you use 5 g of NaOH per litre of oil.
-In processing waste oil you take 5 g +1 g for each ml of catalyst solution you needed for titration. If 4 ml solution was needed, for example then you use : 5+4=9 g of NaOH
-Mix the methoxide until of the catalyst is dissolved. The chemical reaction will make the fluid to get hot. When all grains of NaOH have been dissolved, you carefully add the heated oil. Subsequently you shake or mix it all during 10 to 15 minutes.Leave the oil to rest. In less than an hour already you will see a separation between biodiesel and glycerine

5/Good or not good?

-The test has been successful if you see a distinct dividing line between the biodiesel and the glycerine, the amount of glycerine should be about 10% of the total content.
If less than 10% glycerine forms, then you probably have used too little catalyst, carry out a new test with 0.5 – 1 g more of catalyst.

-If you see a clear layer of soap between the biodiesel and the glycerine, then you probably have used too much of catalyst. Carry out a new test with 0.5 - 1 g less of catalyst.
If you see lumps in the biodiesel, then you have bad oil or the titration was incorrect. Carry out a new titration and make a new test batch from it. If you see lumps again, then you better should not use this oil.

-Leave the biodiesel to rest for 12-24 hours. Dark coloured, somewhat viscous glycerine will have formed at the bottom of the jar, with a distinct dividing line with the pale fluid above it. The colour of biodiesel varies and depends on the type of oil that was used, but is mostly palish yellow. The diesel can be clear, but this is not required per se, it may be very turbid as well. Not to worry. Eventually it will become clear, but there is no reason to wait.

***Warning: Methanol, Methoxide (Methanol/catalyst-mix), and NaOH are dangerous chemicals. Before use always read the safety regulations provided and follow the instructions on the packaging. Always work in a well-aired room and always wear personal means of protection, such as a suitable face mask, gloves and face protection when working with these materials.

How to make BIODIESEL (part 1)

***How to make BIODIESEL
Biodiesel forms due to a chemical reaction called transesterification, meaning that glycerol in the oil is substituted by an alcohol in the presence of a catalyst. In our case we use Methhanol and NaOH (caustic soda) or KOH (caustic potash). In this "How to" we will do our best to make clear to you how to prepare a good biodiesel. Don't let yourself be put off by our method, though. There are many other ways and tricks to prepare good biodiesel and you can find much about it at the other websites mentioned above.

*The 3 ingredients

1/Oil

The primary ingredient is oil or fat. This will be waste vegetable oil for the average producer at home, which may be collected for free in most restaurants.
One can, of course, grow rapeseed or Jathropa and crush it for oil, as often happens in the United States.

Many US farmers are nowadays self-supporting with regard to energy. They use biodiesel in tractors and other farming machinery and mostly diesel aggregates are used to generate electricity. People who prepare diesel on a larger scale are able to use waste frying fat, fish oil, animal fat and several other kinds of oils. The nice thing about biodiesel is that you can make it out of so many different substances, mostly waste products. There is always something in stock, and even the use of new oil is cost-effective still.

2/Alcohol

The second ingredient is alcohol. Methanol is mostly used in the application of recycled vegetable oil. When processing new oil, it is often possible to use ethanol, but as ethanol is more difficult to handle, we use methanol here. We like to point out that methanol is a very dangerous material, as is ethanol. Avoid inhaling and skin and eye contact, always wear gloves suitable for this substance, eye-protection and face-mask and always work in a well-ventilated room.

3/Katalysator

The last ingredient is the Catalyst. Both KOH (potassium hydroxide, caustic potash) and NaOH (Sodium hydroxide, caustic soda) may be used. The advantage of KOH is that the residual glycerine is much less toxic than when NaOH is used. In that case, it is even possible to process the glycerine into artificial fertilizer. KOH dissolves much more readily in methanol as well. However, an advantage of NaOH is that it is very simply and cheaply to get as a plunger, while it is good to handle. That is why we use it in this manual. You can always have a go with KOH as well. Take care that you use NaOH with a purity of 96% or higher. KOH of that percentage is rather hard to find, but 92% and 85% will work fine as well. Both NaOH and KOH are very dangerous chemicals. Please take the precautions mentioned above when using these chemicals.

**How to get OIL
Although biodiesel can be derived from many oils and fats, mostly waste frying oil is used. Restaurants often have to pay for the removal of their waste oils. Therefore it is rather simple to collect oil for free from a restaurant.
The most convenient way is to collect it in its original packaging. Oil mostly is supplied in plastic containers. If your supplier is willing to refill these containers with the waste oil you are certain that the oil is not polluted extra by water, dirt and other externally interfering factors. Another option is that you provide the restaurant with a barrel to catch the oil. Obviously, you can spare yourself the trouble and use new vegetable oil. It simply is for sale at supermarkets and wholesalers.

**Oil quality
The cleaner and newer the oil, the simpler it is to make high quality diesel.
Its colour and transparency tell a lot about oil quality. Light and clear is good; darkand turbid smelly oil is less suitable to produce biodiesel.
When you are not sure of the oil quality, it is advisable to make first a small amount of diesel. If this turns out to be good, then you can process the rest of the oil.
Our manual may seem to be very simple and in fact making biodiesel is not that difficult. It only becomes tricky when you have oil of lesser quality, like oil with much water. Too much water may interfere with the process, especially when you are using too much of catalyst a kind of gel may form. One way to check your oil for water is by heating about half a liter of oil to a temperature of 50º C. If it starts to bubble/hiss/crack etc. then the oil contains too much water. When you do not see any of these phenomenons at 60º C, there is no reason to remove the water.

*note: source from http://journeytoforever.org/biodiesel.html

Tom and Jerry 06

Nu Pogodi 16

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Nu, pogodi! - 03

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Rose

Nu Pogodi 04

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In the museum

On the aeroplane

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The Knockout

Work

Charlie Chaplin Reel 2

A Burlesque On Carmen

His New Job

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