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Sizing of UASB (Upflow Anaeron 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

Condensate Load Calculation

I just read some pages on Handbook of Chemical Engineering Calculations 2nd edition, written by Nicholas P. Chopey and got interested in calculation of condensate load in order to determine the capacity of steam trap. I will take one example, where the steam indirectly heats a liquid through metallic surface, as in heat exchanger and kettles.

Case I

For example, we have 1892.5 L of water heated in 30 min from 22.2 to 100 oC with 50-psig (344.7-kPa) steam in the jacket of kettle. How much condensate formed?

For normal warm up load, the quantity of condensate can be calculated by the following equation: Read More

IP Codes

The IP CodesIngress Protection Rating, sometimes also interpreted as International Protection Rating, classifies and rates the degree of protection provided against the intrusion of solid objects (including body parts like hands and fingers), dust, accidental contact, and water in mechanical casings and with electrical enclosures.

A two-digit number established by the International Electro Technical Commission, is used to provide an Ingress Protection rating to a piece of electronic equipment or to an enclosure for electronic equipment.

The protection class after EN60529 are indicated by short symbols that consist of the two code letters IP and a code numeral for the amount of the protection.

Example: IP65 (NEMA 4)
The two digits represent different forms of environmental influence:

  •  The first digit represents protection against ingress of solid objects.
  •  The second digit represents protection against ingress of liquids.

The larger the value of each digit, the greater the protection. As an example, a product rated IP54 would be better protected against environmental factors than another similar product rated as IP42.

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  1. IP ratings.
  2. IP code.

Chemical Engineer’s Diary: It is not easy to be an engineer

Sometimes, I feel involving in EPC project was such a chaos, totally messed up. The advantages of involving in low-cost project, such as feasibility study, is we are working in a small group of people. It is very easy to coordinate or to communicate, even to share information or transfer knowledge. EPC project is totally different. It involves many departments and involves other people outside the company, such as vendors. Read More

Energy Saving: Its Background


I think the issue in energy saving is getting hotter day by day. A lot of seminars and training were held to create awareness among people to take action on energy saving.When I was pursuing master degree, I took bioenergy as theme of my thesis. I was getting aware on energy depletion, so that it couraged scientists in the world to develop alternative energy to replace petroleum oil. Honestly, the idea of saving energy is pretty new for me although the background is the same as developing alternative energy.

Increasing Demand, Decreasing Supply

Global primary demand is projected to increase by 53% between 2004 and 2030 to over 17 million TOE (ton oil equivalent) – an average annual rate of 1.6%. Over 70% of the increase comes from developing countries. The power generation sector contributes close to one-half of the global increase (source).

Fossil fuel is the dominant source of energy, accounting for 83% of the overall increase in energy demand. For example, oil demand grows by 1.3% annually, reaching 116 million barrel per day in 2030.

No one doubts that fossil fuels are subject to depletion. The availability of oil worldwide has already peaked (source).

One report said that the amount of proved oil left in the world was 1.15 trilion barrels. It would take 41 years for this to be completed. As for gas, the remaining proved reserves was 176 trilion cubic meters or 67 years’ worth of supplies (source).

Increasing Energy Price

Energy price is expected to increase in short and long-term basis. There are several drivers of energy price. The drivers are

  • Demand
  • Reserves
  • Costs
  • Market power (source)

For example, due to declining reserves, oil and gas costs will increase.

Due to the reasons above, the idea of saving energy is very important.


Creating Piping and Instrumentation Diagram: My Real Experiences

Example of P&ID

As already described in previous posts (such as here and here), I was involved in EPC project. Creating piping and instrumentation diagram (P&ID) is one of my responsibility. I think P&ID is a collection of information and collaboration of every discipline, such as process, mechanical, electrical, and instrumentation. Once I think creating P&ID is easy enough, but I change my mind then. It is not.

I revised my P&ID (water treatment plant, fuel supply system, and wastewater treatment plant) several times. I am not quite sure if I am a kind of diligent person, but I am sure creating “perfect P&ID” requires a lot of works and patience. I sometimes think there’s nothing wrong with my P&ID. However, if you let someone, for example your colleagues, your boss, or someone with more experiences than you to check your P&ID, you will laugh at yourself. It happened to me. My P&ID was far from perfect. I understand now. Perfect P&ID requires continuous improvement. Read More

Chemical Engineer’s Diary: to Love What you Do

Today I was asked by operation director in my company. The questions were only three yet simple, but I totally can’t answer properly. The question was,

“What do you learn now?”

I think this is the first time someone in my company asked that question. People usually asks what is your job now? Or in what project are you involved? That’s very common.

I needed a second to find the answer. Then I answered, I kept concentrating on process. Honestly, I’m not sure that’s the right answer. I just need to answer right away.

The second question was

“What topic do you learn?”

I said I learn utilities (not all utilities of course. It’s just water treatment plant, wastewater treatment plant, thermal oil heater, and fire fighting system).

The last question which is the most important

“Do you like learning utilities?”

I just said that was the only job left for me. I kept concentrating, doing, revising, finishing utilities of our current project. I made Piping & Instrumentation diagram, prepare engineering document (such as individual specification, requisition, and other).

I keep thinking about the last question. Sometimes, I want to ask: can we choose what we want to do? It is because we usually do what we need to do or what job left for us. I don’t say that’s good or bad. In my experience, in the beginning of the project I am involved in, I had difficulties to finish my jobs. It took several weeks for me to finish piping and instrumentation diagram. Not only that, I also found difficulties to make document, such as design basis for fire fighting system. And the last one, I felt it is not easy to select the appropriate vendor for our water treatment plant.

Then I learnt. We found difficulties, we learnt, then we solved them. That’s life. And when you solved them, you feel like a genius like Einstein. I felt that way.

I always remember this

It is hard to always do what you love because sometimes you need to do what you don’t love. But you can put love in everything you do.

That makes me strong until now as inexperienced engineer who wants to be a professional.


If I were not working as chemical engineer

About two days ago,  I had a short yet inspiring conversation with my boss about one alumnus who works as commissioner in waste water treatment plant company. He’s chemical engineering student from ITB class of 1995. My boss said that there was a tendency among chemical engineering alumni class of 1995 to develop their own business. Class of 1988 also did so.

Then I asked my self. I didn’t find the answer. My boss said the working tendency can see seen seven to ten years after I graduated. So I will find the answer in 2016-2019.

I sometimes imagine what kind of people I will be in the future? Will I be the same person as I am today? Will I still work as chemical engineering consultant? Or will I be someone totally different? I don’t know. But I do feel I will be totally different person in the future.

I will be working for one year in this company by next month. I still have one question in my mind: do I love what I do.  I find it’s natural for someone to love and not to love some parts of their work. It also happens to me.

I also imagine if I were not working as chemical engineer, what would I do?

1. Full time blogger

I have been actively blogging since 2006 and I start to understand blogging and writing is part of my life. I had experience making money by writing (although it’s still amateur).

I keep writing and blogging after work hours to heal my self and find self enjoyment. I feel much better at work after fulfilling this hobby.

2. Teacher

If I were not working as chemical engineer, I would like to be a teacher, especially elementary school teacher. I love kids and I love to develop them emotionally and intellectually. I realize sharing and develop people to be a better person is my passion. I feel like I have ability to explore someone’s personality and help them to accomplish their goals in life.

3. Researcher

When I was a kid, I sometimes thinking I was born to learn in my whole life. I also imagined to have my own lab at home. When I pursued master degree, I realized working on lab excited me very much. I enjoy working overtime and dealing with microorganism, reading journals, and try new methods and see the results.


How to Evaluate Technical Specification of Water Treatment Plant Package Unit and Get Cheaper Price

In EPC project, the activity after engineering is procurement. When we want to procure something, for example water treatment package unit, boiler, fire fighting pump, or else, we usually invite several qualified vendors to bidding and get the price. We usually find the price of several equipments quoted by certain vendors is so high but the technical specification is about the same. I will share my experience about how to evaluate technical specification of Water Treatment Plant package unit and to get cheaper price. I take Water Treatment Plant as a case in this post because I feel I have more knowledge in this area than in other areas.

Evaluating Multimedia Filter Package Unit

Multimedia package unit in Water Treatment Plant is a pretreatment used to remove total suspended solid. It consists of two to three kinds of filter, such as silica sand, activated carbon, and gravel. Some water treatment plant vendor may offer additional carbon filter in separate vessel (so the pretreatment consists of two vessel, multimedia filter vessel and carbon filter). The function of carbon filter mainly is to remove iron and manganese. Iron is a big problem when it clogs reverse osmosis unit so that we need to remove it first.

I list some potential cost reduction in multimedia package unit in water treatment plant. You can discuss with the vendors about this cost reduction possibility without sacrificing the quality and quantity of treated water.

  • Makes sure the capacity of multimedia filter and carbon filter is correct. Due to mistakes or something, some vendors may offer larger capacity than what is enough. The lower the capacity, the smaller the tank, the lower the media, and of course the lower the price
  • If the vendors offer multimedia filter and carbon filter, you need to negotiate the possibility to reduce the amount of media. For example, if vendor offer two kinds of media in multimedia filter (for example silica sand and activated carbon), you may ask to get silica sand in one multimedia filter and activated carbon in carbon filter.
  • Check the thickness of tank painting thickness. If the pressure of the vessel is not so high, you can ask to get thinner painting thickness. It will reduce some cost.
  • Check the instrumentation. The most important instrumentation for multimedia filter is pressure indicators. You need to install them to get the indicator when the multimedia filter need to be backwashed. Sometimes, the vendors offer safety valve or air venting. You can discuss the importance of this instrumentation.
  • Use existing pump to backwash multimedia filter, don’t buy dedicated one. I reccommend to use existing pump to backwash multimedia filter and not but the dedicated pump to wash multimedia filter

Evaluating Reverse Osmosis Package Unit

Reverse Osmosis water treatment plant is a filtration process use to purify water. It uses to reduce the total dissolve solids and chemical impurities from water. In water treatment plant, reverse osmosis unit is constructed as skid mounted type, consisting of the RO feed pump, cartridge filter, RO high pressure pump, reverse osmosis membrane and pressure vessels, control valves, piping, and all necessary accessories and instrumentation.

Fluid PhaseFluid Condition/DescriptionTube SideShell Side
LiquidProcess Fluid1-2 m/s
Max 4 m/s
0.3-1 m/s
Water1.5-2.5 m/s0.3-1 m/s
VaporVacuum50-70 m/s50-70 m/s
Atmospheric10-30 m/s10-30 m/s
High pressure5-10 m/s5-10 m/s

Before we discuss about how to reduce reverse osmosis package unit therefore reduce overall cost to buy water treatment plant package unit, there are several technical aspect you need to make sure when you read the technical specification of reverse osmosis.

  • Make sure you give correct water feed specification and correct desired water specification (what is the SDI and TDS of your feed water, what is the desired SDI and TDS?). Membrane element will be selected based on feed water salinity, feed water fouling tendency, required rejection, and energy requirement.
  • Make sure vendors simulate reverse osomosis membrane system using appropriate desired water parameter

Click here if you want to read more about designing membrane reverse osmosis in water treatment plant.

This is a short list of potential cost reduction of reverse osmosis water treatment plant.

  • Use RO feed pump as cleaning pump. I found some vendors do not offer dedicated cleaning pump in CIP cleaning system. They prefer to use RO feed pump as cleaning pump. I just found a reference that mentioned cleaning pump for CIP should be low pressure pump to minimize production of permeate and to avoid dirt redeposition on membrane element. The material should be SS316 or non metallic composite plastics.
  • Take a look at instrumentations. I personally do not reccommend this method. The vendors may offer several instrumentations that seems too many. However, we need to pay attention carefully to their experiences. They usually have several reasonable experiences about the importance of installing the instrumentation. For example, the vendor offer you two units conductivity meter at inlet of reverse osmosis unit and at permeate line. You may think one unit conductivity meter at permeate line is sufficient to determine the quality of treated water is at desired level. In my opinion, you will wonder what the initial water conductivity is and to what extent it’s reduced.

Evaluating Mixed Bed Polisher Package Unit

In water treatment plant, mixed bed polisher is usually installed after reverse osmosis unit when the water quality of less than 1 microohm conductivity is required or higher degree of safety is required to ensure water quality (source). Another source mention that the mixed bed should be about 0.10 microSiemens/cm at 25 degree C and 0.010 to 0.020 mg/L as SiO2 (10 to 20 ppb).

In mixed bed polisher, anion and cation are joined in a single vessel. The two resins are intimately mixed by agitation with compressed air.

I found mixed bed polisher usually contributes the highest price among other water treatment plant package unit because it operates automatically. I have ever asked one vendor about the possibility to change the operation mode of mixed bed polisher from automatic to manual. They said the cost will reduce very significantly.

When you read technical specification of mixed bed polisher for your water treatment plant, you also need to consider the consumption of instrument air because the system uses instrument air during regeneration. You need to check if the consumption is still sufficient with the production of instrument air, unless you need to buy blower.

Although it operates “manually”, you still need alarm if the conductivity increases the level that required regeneration or you need to present the value of flow, conductivity, and pH of treated water in central control room.

Sometimes I found some vendors offer regeneration pump for mixed bed. You may discuss with them about the possibility to  use ejector instead of pump so that the cost will reduce.

I hope this summary will help you determine the best price of water treatment plant package units and acceptable water quality. 🙂

Chemical Engineer’s Diary: How far I have grown?

About five days ago I got an email from my boss. He asked my opinion about working in this company. Honestly, I have been asking myself how far I have grown as chemical engineer who works as consultant. I found the answer was very hard. I am not quite sure I have grown a lot as chemical engineer.

I have been working in this company since November 2011, so it’s been nine months. I have involved in six projects, one pre-feasibility study project, one bankable feasibility study project, three energy audit projects, and one engineering project (make piping and instrumentation diagram mostly). Although my project is quite a lot, I think my chemical engineering knowledge improved slowly. This is regrettable, but I need will not stop to create many ideas to improve ability. Read More