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Microbial Inhibitor for Cooling Water Treatment

My company is trying to be a vendor of small equipment package, such as chemical injection. I actually have a limited knowledge about this area, but in my understanding, chemical injection package is very simple. It usually consists of chemical storage tank, dosing pump, mixer, and accessories, such as low level switch, controller, and so on. The job became a  bit complicated when we don’t have enough knowledge about that.

However, to improve the ability as a vendor, my company decides to try to enter this area. The good news is I also participate. 

Our first project is to supply chemical injection system for cooling water treatment.  Read More

Sizing of UASB (Upflow Anaerobic Pond) for Wastewater Treatment Plant

I think this is my first time I learnt about Upflow Anaerobic Sludge Blanket (UASB). I’ve ever learnt about anaerobic wastewater treatment, however I don’t have any idea about UASB and what the differences are. Since I am responsible as engineer in wastewater treatment package, I need to learn about UASB (there is a possibility that this system will be included in the package).

What is Upflow Anaerobic Sludge Blanket? Read More

Why do we need to make complete technical bid tabulation, requisition, or data sheet?

Now I undestand. People said experience is the best teacher. I think that’s true.

I have already follow procurement of several equipment package since the beginning. I compared my preparation and others (especially preparation of engineers from our head company). My preparation was way way incomplete. I felt the effect right now.

One of my colleague asked me if the internal of pressure vessel in water treatment plant will be spark tested or not. The purpose of spark testing is to determine if there are leaks in the rubber lining and identify the locations. It is a mandatory test in rubber lining tanks.

So, what is the problem? The problem is, for any reason, the appointed vendor cannot perform the test. They just give us the guarantee that there will be no leaks in the lining.

I have googled and found that some vendors perform pre- and post-cure inspection for rubber linings. I got to understand that the test was very important.

Back to the topic. I wish I could turn back time and wrote on my technical bid tabulation and requisition, and data sheet about the point. I did not have spend time to focus in such details. That’s something which is not our concern at the beginning and at the last it became a problem.

Lesson learnt: be detail in making technical bid tabulation. Consider many factors. Ask your colleague or somone who has more experience than you. 

Discussing about Fire Extinguisher with Vendors

Yesterday I got a quite tough and long discussion with one of fire extinguisher product vendor. I learned that I need to define what I really want, what scope of supply is, and what scope of works is. The discussion became very unefficient at the beginning because of those issues. My action was late so that I could not control the discussion. Fortunately, it was clear at the end.

I have created material take off for fire extinguisher and other related products, such as hose reel, potable fire extinguisher, manual alarm pull station, smoke detector, hydrant pillar, hydrant box, siamese connection, and water spray for the tanks. However, there were several issues that has not been addressed. Honestly, the discussion broadened my knowledge because the vendor has a lot of experience (I think). In this post, I want to share to you some of the points. Read More

Water Chiller Inspection: My First Experience

Today, the project manager our EPC project asked me to participate in water chiller inspection in Cileungsi, Bogor, Indonesia. It was my first time. So, I felt a bit excited as well as confused. On that inspection, my role was to inspect the equipment and the technical aspects. I actually did not have any idea about the equipment, except the function.

Simply, we can say water chiller is a refrigeration device. It is used to cool a process fluid. A chiller will use either a vapor compression or absorption cycle to cool.

Type of Industrial Chiller

Figure blow shows type of industrial chiller.


Component of Chiller

The basic component of chiller are compressor, evaporator, condenser, and thermostatic expansion valve.

Wastewater Treatment System

A few weeks ago I got a discussion about wastewater treatment system in our proposed plant. I discussed with one of my colleague. He said, “Let the nature works! Let it process the wastewater by itself”. It sounds weird at the first time. But he’s right and he’s a bit wrong.

He’s right because the natural water in streams, rivers, lakes, and reservoir have a natural waste assimilative capacity to remove solids, organic matter, even toxic chemicals in wastewater. He’s a bit wrong because the process takes a really long time. That’s why we need wastewater treatment system to make it quick (read more in Water and Wastewater Calculation Manual). Read More

Hydrostatic Test for Boiler

I just got an opportunity to witness hydrostatic test for boilers in my recent EPC project. Hydrostatic test is the most common procedure used to qualify newly manufactured pressure pressure. The purpose is to make sure here is no leak in the boiler.

The procedure was quite simple yet important. Pressure parts shall be subjected to a hydrostatic test pressure which at every point is at least equal to:

1.5 times the MAWP (Maximum Allowable Working Pressure) for ASME section I code.

1.3 times the MAWP for ASME section VIII Div. I code

(The MAWP may be assumed to be the same as the design pressure)

The design pressure of my boilers is 10 barg. When this test applied, the QC engineer increased the pressure of boiler to 10 barg and hold it for 15 minutes. They checked visually the internal of boiler if there’s a leak. Unfortunately, there’s no digital recorder available to record the pressure of boiler during the test. So, we needed to check by our naked eyes the pressure gauge.

After 15 minutes, the increased the pressure to 15 barg at hold it for an hour. After that, they decreased the pressure to 10 barg again, hold it for 15 minutes, then decreased again to 1 barg. The inspection was done visually.

Assessment of Cooling Tower Performance

Yesterday, I just got an opportunity to inspect some of cooling tower equipment, such as motors, fans, fan stack, low oil level switch, and so on. It was great. I got more understanding about the system, which is very valuable for me as young chemical engineer.

Before I do the inspection, I tried to learn something about cooling tower. I found from this link about how to assess a cooling tower. In this post I want to give you an example of my own cooling tower.

There are several parameters to assess the performance of cooling towers. Note: CT = cooling tower; CW = cooling water Read More

Calculation of Water Spray for Fire Protection of Vertical Vessel

I just got an assignment from my boss to calculate fire protection of vertical vessel. NFPA 15 (National Fire Protection Association 15) is a standard for water spray fixed system for fire protection.


As per NFPA 15, water spray refer to the use of water in a form of having a predetermined pattern, particle size, velocity, and density discharged from specially designed nozzle devices. Read More

Design Criteria of Wastewater Treatment Plant

treatment plants_clip_image001

As already explained in previous post, design criteria is guideline values for designing new wastewater treatment facilities which is determined through research and laboratory scale model studies as well as operational experience. In this post I want to discuss more about the design criteria of wastewater treatment plant. It is important to note that the design calculations are usually based on certain assumptions. Hence, it is important  to have a clear understanding about the concept of design criteria and the significance in determining capacities and dimensions and wastewater treatment units. Read More