3rd Anaerobic Sampling (Day 7) on 26th November 2010 (Friday)

Firstly, I wasn't at the farm today, but a zillion thanks to Brenda for her brilliant job and for updating me!!!

This girl just amazed me at how "horribly" neat she can get, even though this is not usually the case...

Visually, something didn't seem right with the grey digestor sight glass. If it is truly anaerobic condition, why would alage/ mould grow on the tip of the sight glass?
 

The overview of the sight glass (a well-mixed slurry):

The bottom of the sight glass seems unusually red:

If you were to compare the grey digestor sample (Left) & Orange Digestor (Right), the orange sample seems physically clearer, even though the sample has a higher turbidity and suspended solids concentration. It's not very apparent in the photograph though.

Result of COD Test, after 2-hour reaction time.
From Left: Blank, Grey Digestor, Orange Digestor:

 

Result of Phosphate Tests (From Left: Grey, Orange Digestor):

As for Nitrate Tests, you may observe a brown liquid layer floating on top of a transparent layer:

TOC tests before reaction (colour is blue):

TOC Test, during reaction in the thermo-reactor (colour changes from blue to brown):

Result of TOC Tests (From left: Grey, Orange Digestor):

Conclusion of Tests:

We have very good results to show - results are showing an expected trend as per hypothesized, with the only exception that COD in Grey digestor increases from Day 5 to 7. A higher COD would mean a poorer waste treatment efficiency.

Digestors are functioning as per normal, with the orange digestor generally showing a better performance than grey digestor. Further analysis would be addressed in report.

Next test would commence on 1st December 2010 (Wednesday).



Kian How, signing off on 26/11/10, 11.10 pm.

2nd Anaerobic Sampling (Day 5) on 24th November 2010 (Wednesday)

 
As per usual, the thorough tests started at 3pm and ended at 11.30pm.

Before that, Farmart Bus Timings are as follows; good to keep note:

Bus Timings for weekdays:

Bus Timings for Weekends and public holidays:

This was how the waste in the Grey Digestor looked like on Day 5, the 1ml syringe can do wonders; we used it as a substitute for micro-pipettes:

The condition in the orange digestor (12 vol% cow dung):

The blue colour change upon addition of test reagents was attributed to the presence of phosphates; different colour intensity indicates varying phosphate concentration in the 2 samples.

             Left: Grey Digestor                                    Right: Orange Digestor 
 

It's getting really dark now... Look at the moon... It's 11.30 pm... Really Late...

The interior of the cab on the way home; exhausted and penniless with all these late night "cabbings" and "on-calls" from the secluded farm:

Conclusion:

Since this happens to be day 5 (or to say, we planned for it), we are able to calculate the BOD5 with the data we have on hand.

The team would be going down to SVF on friday to do another set of test for detailed data analysis. To effectively plot a graph for evaluating digestor performances, 5 data points are needed from the anaerobic stage.



Kian How, signing off on 25/11/10, 11.50 am.

1st Double Digestors Sampling (Anaerobic Stage Day 0) on 19th November 2010 (Friday)

 
Lots of things done, spent 1 full day on sampling and testing:

• 2 - 4 pm:     Installed fittings & Data Logger
• 4 - 10 pm:   Through testing of digestor concentrations
• 10 - 11 pm: Packing up

Eng Guan ran out of stock for the 3/8" nipple and N-cap (backwash valves); but the rest of the fittings were completed:

This was how the sight glass containing 12 vol% cow dung looked like - very well-mixed, we should expect some good results from the testing:

 

Spray paint can do wonders, don't they?

Everything was in a total mess when we were doing testing - we really need a cabinet for storing all these expensive equipment and chemicals:

From Left: Mr Kon's Weighing Balance & Colorimeter (Hach), Ms Yang's Photometer (WTW) and Mr Ting's Photometer (Hach); a combination of these 3 concentration analysis devices made thorough sampling possible:

The very much sought-after thermoreactor (COD reactor):

Brenda's doing the serial dilution; it's pathetic to use a syringe to measure 1ml of chemicals, etc - we need a micro-pipette:

The Sulphate Test - Basis for High H2S output:

2 layers of precipitate and solution was observed. Subsequently, cuvett was inserted into photometer for sulphate analysis:

Look at the sky, it's pitch-black!!!

Time check: 10.47 pm!!!

 

Totally exhausted, but well worth the effort as test results fell within expected range. Some analysis that the past batches did not conduct for orange digestor include:

• Suspended Solids:  1270 mg/L
• Turbidity:                1640 fau (with 10 fold dilution)
• TOC:                     110 mg/L
• D.O:                      1.34 mg/L
• Sulphate:                87 mg/L
• pH:                        7.7

In the future, to do:

• TOC & COD tests first as they require 2hrs heating
• Loan out Micro-pipettes from Mr Yeo
• Loan out pH meter from Mr Yeo
• Ask for Cabinet with lock from uncle Chris
• Return Weighing Balance & Trolley to Mdm Tan
• Buy Kang Kong/ Alifafa Seeds

Kian How, signing off on 21/11/10, 2.15pm

Loading of Both Grey and Orange Digestors with Animal Waste on 12 November 2010 (Friday)

 
To get comparative results, we loaded both grey and orange digestors with the same batch of waste; ie concentration was exactly the same - to obtain fair comparison of results:

This was how the manure look like in the grey digestor (human waste); before we replaced it with cow dung.

There it is - 90L of pure cow dung - collected by brenda and marcus on thursday; we spent almost $100 on transportation yesterday - renting a van, etc:

Manually mixing the cow dung so the it solubilizes in water; to attain an optimum concentration of 10-12%:

Here's one crazy fellow who put her whole arm into this pail of shit without gloves!

Click on image to zoom in on her hands!

Completed manually mixing "shit" with water after 2hrs+:

Close-up of the cow dung (12% concentration by volume) :

The vacuum  truck in action:

Sorry Brenda! What if Marcus was the camera man and his reaction is slow towards the end of the video clip? He'll get into deep shit !!

That was why the clip stopped suddenly. Great Reaction for jumping away, Brenda !!

The much awaited 5-gas detector; yet to learn to use:

Testing of the manual digestion processes would commence on a daily basis with effect from 17/11/10. However, gas testing would only be done ONCE at the end of the experiment to ensure minimal loss of biogas.

In doing so, this also ensures complete anaerobic conditions in the orange digestor which has no check valve mechanism - opening the air valve would introduce oxygen into the system - undesired.

In summary, to do next Wednesday - hari raya:

1) all 3 to be present on wed; double-D sampling (full day) - Brenda inform uncle chris

2) denise, hopefully, can come down to help - marc call

3) brenda - potassium test - monday

4) HAZOP on wed, all 3 to bring laptops (KH + Marc HAZOP, Brenda logbook)

5) Kang Kong seeds - buy from nursery

6) Hose - Marc

7) Data logger - Marc/ KH

8) Chain and lock for trolley

9) Fittings - Marc

10) Testing on Thurs/Fri/Sat in pairs
11) Sticker Labels on Grey Digestor - KH

12) Plant Nutrients Deficiency Read-up (Marcus to read KH's Link)

13) Talk for Juniors?

Kian How, signing off on 12/11/10, 11.10 pm.

2nd Grey Digestor Loading & Sampling on 3rd November 2010 (Wednesday)

  

First and foremost, thank you Mr Ting for providing us with the blender!! This blender works as a substitute for homogenizer, which is way beyond budget:

Chocolate Powder    +        Blender            =      Chocolate Ice Blended

(Click on image to enlarge)

Yup, Mr Ting, here's our token of gratitude; Bubble Tea!

Wait... I remember Mr Kon likes orange juice, let us add in some methyl orange...
Mr Kon... You wait! Good food is definitely worth the wait...

On on serious note, the was how the vacuum truck loaded the waste:

 

2 weeks and rusting occurs, we'll be getting some silver spray paint:

Mr Kon, look at the PI. After 1 week+, gas output is still 0. The failure was expected as I told you earlier that the concentration was way too low; we can't do a direct loading from PUB. We will be manually diluting the waste. Please get the next batch to design a method to control the loading sludge concentration to be between 6-12% (optimum standards).

Something I planned for 3 hours, and ended up we had insufficient chemicals again. On a bright note, the sulphate concentration exceeded the colorimeter measurement range (> 80mg/L); this proved that our hypothesis on the human diet and high H2S output is on the right track. We will be approaching Ms Yang on the photospectrometer usage, which provides a greater measurement range.

The manual loading process:

Now you know why I insisted on getting a 50 cm stand for Brenda
(see below: she's short)...

The primitive manual agitation for 3rd world countries:

Note: Take extra caution to decommission the anaerobic stage isolation valve before agitating the waste. You risk pumping the waste to the next drum.


This  is when "Operate" in CDIO comes in. During the design stage, we did not foresee that the pressure in the anaerobic stage due to agitation would cause the sludge in the sight glass to be transferred over to the next drum.

Hence, we surmounted this issue by going back to "designing" the operation procedure (by decommissioning the isolation valve before every agitation).



Kian How, signing off on 04/11/10, 1.15 am