# Haya

Senior Members

53

## Posts posted by Haya

### What is this symbol?

Yes, for the most part. But can be interpreted more broadly than that. A errors may come from other sources such as the error in constants.

Uncertainty might be a better word. All measurements have a limited precision.

Thanks

### What is this symbol?

Plus or minus.

So 5 pluss or minus 2 means either 3 or 7, normally this implies the error bars. So the number is in the range of 3 to 7 but we measured 5.

Do you mean the error that occurred in measurement?

Plus-minus. If some device is, say, 6 volts plus-minus 1 volt it means that it is 6v within a variation of 1v either side.

Its the plus-or-minus sign. You will see such signs typically in the overroot of a perfect square, and also in the quadratic equation formula.

Thanks

### What is the seed inoculum?

It is seeded with a substance (the inoculum) that populates the digester with bacteria.

Thank you but please, could you explain that in more details?

### Is this equation right?

Methane from water and carbon dioxide? Cool!

You would have 2O2 left over i think. And you would need something to "make it happen"

Obviously it's not right, as Hydrogen atoms on the left (side of equation), does not match Hydrogen atoms on the right,

Oxygens atoms on the left, does not match Oxygen atoms on the right..

ps. Are you in the 1st class of the primary school.. ?

bah details

???

CO2+ 2 H2O -> CH4

Still does not match...

got me stumped

Forget balancing, is the equation possible???

Let's take it the other way:

CH4 + 2O2 = CO2 + 2H2O

The equation balances and portrays the burning of methane in oxygen. So the OP really seems to be asking "Is this a reaction that can be driven in the opposite direction?"

I imagine that under high pressures and possibly high temperature it might be possible, but my gut reaction (very scientific) is no. Where are the chemists?

Edit: It occurs to me that since the reactions shown is exothermic, then the reverse reaction if possible would benefit from high temperatures. i.e my "possibly high temperature" would become "and definitely high temperature".

Apparently archaea can metabolise this reaction. Have no idea if the article is correct. Its very vague.

http://www.zdnet.com/article/h2o-co2-ch4-thanks-to-archaeans/

CO2 + 2H2O ---> CH4 + 2O2

Interesting, but I suspect there would be a plethora of intermediate products, which is not quite the same thing.

I read it on the internet and i thought it was wrong. I just wanted to make sure about it. What i know that carbon dioxide and steam give off H2CO3 that is a weak, unstable acid.

CH4 + 2O2 ---> CO2 + 2H2O

CO2 + 2H2O ---> CH4 + 2O2

May be the first reaction is driven in the opposite direction as shown in the second reaction, but it seems that it needs high pressure and temperature. However, it may be wrong after all.

CO2+H2O=CH4

### What is the seed inoculum?

"In field implementation of anaerobic digestion, the animal manure itself acts as seed inoculum and the process may reach its stability within 20-30 days of operation".

What is the meaning of seed inoculum?

### The job of anaerobic digester

Given that the displacement tank level is above the main tank it probably acts as a safety regulator for the pressure inside and should the gas outlet pipe be turned off or blocked the build up of gas will push the slurry level down and allow the gas to escape through the outlet pipe and lift the loose cover.slightly to escape; kind of a crude one-way valve.

Thank you for your help but i'm sorry, my original language isn't English and i can't understand you. Could you say that again in a more simple way, please?

### coagulation activity in water treatment

That is problematic. Is your query directly related to water purification, or to these processes in general? My exposure to them relates to their role in drilling fluids.I'm not sure my input would be of much help.

Edit: Excuse me. You clearly stated in the title that this was for water treatment. Sorry for missing that.

My queries are related to those employed in water purification not in general.

### coagulation activity in water treatment

There appear to be abundant items relating to these mechanisms revealed by a google search. Is that not working for you?

My original language isn't English and google search explains them in a complex way for me, so i need someone make them simple and easy to understand.

### coagulation activity in water treatment

"Particles can aggregate and settle out of solution through four basic mechanisms: double layer compression, sweep flocculation, adsorption and charge neutralization, and adsorption and interparticle bridging (34, 35)."

I can't understand these mechanisms, would someone explain them, please?

### What is HRT?

What is the meaning of hydraulic retention time (HRT) in anaerobic digestion?

### Dispersed-growth bacteria and attached-growth bacteria

What is the difference between dispersed-growth bacteria and attached-growth bacteria?

### The difference between anaerobic and aerobic bacteria

These are specific terms typically used in engineering. It would help if you could elaborate on the abbreviations and add what you think they could mean.

Thanks! I will try to know.

### The difference between anaerobic and aerobic bacteria

Yes and no. For the most part anaerobic bacteria as a whole are able to degrade most compounds that are degradable under oxic conditions. However, the pathways are different, as they e.g. cannot use oxygenases. As a consequence anaerobic degradation tends to be much slower. Also it often requires the action of larger communities as a single species may not completely decompose the substrate.

Even in cases where oxygen itself is not involved in the degradation process, anaerobes are often somewhat more energy limited than aerobes, which to a large part is the inherent inefficient of anaerobic respiration but also due to the fact that many anoxic habitats can have other unfavorable aspects (such as nutrient limitation, for example).

Thanks!

I am working on anaerobic digestion, could you explain me this equation because i can't understand it, please?

(BODL stabilized – BODL for cell production)

And what is the difference between dispersed-growth digesters and attached-growth digesters?

### The difference between anaerobic and aerobic bacteria

What is the difference between anaerobic bacteria and aerobic bacteria whence the ability of decomposition of organic matters? Can anaerobic bacteria decompose something like straw?

### ASTM standards

" are these societies ranked from the most recommended to the least?"

No

How good a standard is depends on what you want it for.

Thank you so much!

### ASTM standards

What do you mean by "best"?

ISO standards are recognised throughout the world.

What i mean is that there are a lot of societies that put standards for experiments and tests including ASTM, AWWA, ISO....etc, are these societies ranked from the most recommended to the least?

### ASTM standards

Hi,

isn't there any way to get the astm standards for free? Is astm the best for standards?

### what is the meaning of waste stabilization?

Yeah, it is me fault, sorry. The second topic has been removed.

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