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Design Criteria of Wastewater Treatment Plant

treatment plants_clip_image001
http://www.lacsd.org/wastewater/wwfacilities/moresanj.asp

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

Design Philosophy of Wastewater Treatment Plant

http://www.wedotanks.com/anaerobic-aerobic-wastewater-treatment-plant.asp

After we discussed about water treatment plant, I want to share my new task about designing wastewater treatment plant. The explanation in this post will be quite simple and not really deep because I also still learn the fundamentals of designing water treatment plant. But after I discussed with one wastewater treatment plant vendor, I got more understanding about the plant and basic consideration in designing what equipment or process required in wastewater treatment plant. Read More

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.

 

Recent Energy Status in Indonesia

Energy security is a big concerns of almost every country. Most of countries, like Indonesia, relies on petroleum oil as main energy source. As a big population country, demand energy and resources will increase in Indonesia. In addition, the issue concerning climate change, pollution, and improving life quality for people encourage us to seek alternatives of fossil fuel.

Energy Shortage

Indonesia is facing a long-term problem: energy shortage. Dahlan Iskan (ex-CEO of State-owned Power Company, PLN) also admitted the country’ supply of electricity is very limited. PLN has encountered power shortages in 250 regions, including 243 location in eastern Indonesia (source). The reason of power shortage in some areas is due to inadequate transmission and distribution infrastructure (source).

Energy Consumption

Total energy consumption in Indonesia per capita remains low. In 2009 it reached 0.8 toe compared to world average of 1.8 toe (source).

Indonesia has a wide variety of energy resources, including fossil and non-fossil resources. The major energy resource fueling Indonesia’s economy is oil, providing 32% of total. Biomass came second with 27% particularly in the more remote areas that lack to Indonesia’s energy transmission network, while coal accounted 19% to fuel new power generation, gas for 18%, and primary electricity (hydroelectricity, geothermal) for 4% (source).

Electricity consumption per capita is very low and reached 570 kWh in 2009, compared with a world average of 2500 kWh. Energy consumption has increased by more than 8.5% per year since 1990, more rapidly than total energy consumption. It is due to the use of electricity in all sectors and the increase in the country’s electrification rate (source).

Net Importer of Oil

Indonesia is currently a net importer of crude oil and refined product. Indonesia is the only OPEC member (Organization of Petroleum Exporting Countries) that is the net oil importer. Its oil production has declined over the years owing to ageing of oil fields and lack of investment in new equipment.

Natural Gas

Indonesia is ranked eighth in world gas production with proven reserves of 108 trillion cubic feet in year 2010. This ranks eleventh in the world and the largest in Asia Pacific region. Gas reserves are equivalent to three times Indonesia’s oil reserves and can supply the country for 50 years at current production rate (source).

Clean Energy Regulatory Framework

The energy sector in Indonesia is dominated by four key policies and objectives:

  • Diversification: to reduce dependence on oil by expanding the use of coal, gas, and renewable energy resources
  • Rational energy pricing: no longer sustain uniform pricing for electricity and petroleum products across country, and it has begun to eliminate subsidies
  • Energy sector reform: the combination of decentralization of government decision-making to give greater involvement to regional authorities
  • Rural electrification: bring electricity to 90% of population by 2020

The energy law no. 30/2007 provides a renewed legal framework for the overall energy sector with emphasis on economic sustainability, energy security and environmental conservation. National Energy Council (DEN) was established under this law with the task:

  • formulating and implementing national energy policy
  • determining national energy general plan
  • planning steps to overcome any energy crisis or emergency (source)

The national energy policy  is the overall management of energy and will address issues such as:

  • the availability of energy to meet the nation’s requirements
  • energy development priorities
  • utilization of national energy resources
  • national energy buffer reserves (source)

The basis of renewable energy development in Indonesia is Presidential Regulation No. 5/2006. It sets national energy targets for an optimal energy mix in 2025:

  • less than 20% from oil
  • more than 30% from gas
  • more than 33% from coal
  • more than 5% from biofuel
  • more than 5% from geothermal
  • more than 5% from other renewables, especially biomass, nuclear, micro-hydro, solar, and wind
  • more than 2% from liquefied coal

Potential of Renewable Energy Resources

Renewable energy resources have been largely unexploited due to the perceived high up-front cost and lack of infrastructure to match supply with demand (source).

FluidDescriptionPressure Drop (kN/m2)
LiquidViscosity < 1 mN s/m235
1-10 mN s/m250-70
Gas and VaporHigh vacuum0.4-0.8
Medium vacuum0.1 x abs pressure
1-2 bar0.5 x system gauge pressure
Above 10 bar0.5 x system gauge pressure

Geothermal 

Indonesia has significant geothermal reserves (around 40% of the world’s reserves) and the potential to produce 27,710 MW of electricity. However only 1,200 MW of power capacity has been built.

Based on the National Power General Plan and Presidential Regulation No. 5/2006 the contribution of renewable energy is to increase from its current 5% to 17% of the total energy consumption in 2025. Geothermal is expected to account for 5% of the contribution of renewable energy with a target 9,500 MW by 2025 (source).

Solar photovoltaic 

Solar energy in Indonesia is quite large and reaches 4-5 kWh/m2, but the efficiency of solar photovoltaic cell has only reached 10%. Since investment cost of solar PV is very high although fuel cost is zero, the electricity generation from solar energy is less competitive compared to other energy. However solar energy in the form of solar home system will be utilized in remote areas where no other alternative sources for electricity generation (source).

Biomass

Electricity generation potential from the roughly 150 Mt of biomass residues produced per year to be about 50 GW or equivalent to 470 GJ/year roughly (assuming the main source of biomass energy in Indonesia will be rice residues with a technical energy potential of 150 GJ.year, source). Other potential biomass sources are rubber wood residues (120 GJ/year), sugar mill residues (78 GJ/year), and palm oil residues (67 GJ/year).

Micro Hydropower

Indonesia has abundant hydropower resources and has been successful in developing micro, mini, small, and large hydropower plants over the past decades. Small hydro potential is distributed around islands, can be developed as local energy resources especially in remote areas for rural independent power supply.

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. 🙂

More about Water Treatment Plant: Methods to Remove Taste and Odor

Last week and today I met some Water Treatment Plant vendors to discuss about technical clarification. Some engineers and my boss have discussed the possibility to reduce the money to purchase water treatment package and make the system more simple. The main purpose the technical clarification meeting was to inform vendors what we want in our Water Treatment Plant, to ensure that is possible, and to ask for quotation, of course.

My boss is a very intelligent chemical engineer therefore I learn much about Water Treatment Plant from him. The vendors also told us about technical consideration in their water treatment plant configuration so that we understand a bit the reason behind their configuration selection. Of course we want to choose vendor who can offer best price and acceptable water quality (mainly for boiler feed water). Read More

What is Redwood Viscocity

I just got a really embarassing experience as chemical engineer. Sometimes we deal with a really complicated problem and we can handle that. On the other hand, we handle a simple problem, but we can’t handle that. How if a chemical engineer can not convert the kinematic viscosity expressed in Redwood second into dynamic viscosity? That is my problem. It happened about two days ago. My boss apparently was really disappointed. Read More

How to Calculate Jockey Pump Capacity in Fire Fighting System

Main_fire_pumps_with_Jockey
http://en.wikipedia.org/wiki/Fire_pump

About two days ago, my colleague asked me about inconsistency in our design basis of fire fighting system of our on-going project. In our design basis, we stated that the capacity of jockey pump is 50 gpm (the capacity of main fire pump is 500 gpm for electric motor fire fighting and diesel engine fire fighting, respectively). But vendor who supply fire fighting package stated that they will supply jockey pump with the capacity of 25 gpm. It would be a problem if the Construction Management (the one who monitors and review the product of the project) notices this. The question that will be come up is are you sure the capacity of jockey pump (which is 25 gpm) is enough in case there is a fire? The question rises in my mind is

How to calculate jockey pump capacity in fire fighting system? Read More

Basic Engineering Design

basic engineering
http://www.list.ch/competence/basic-engineering.html

Today I got a very nice meeting about three upcoming projects in my company. One of them is Basic Engineering Design. The meeting was attended by several engineers from my company and the team from our client.

The Basic Engineering Design was follow-up of our previous meeting: pre-feasibility study. We had about one hour discussion about the topic and we faced one problem here: the possibility to change basic engineering direction. Some people debated about the topic and the rest of them wished to get decision faster. But for us, as chemical engineering consultants, we tried to think carefully but we hoped to move quickly.

Read More

Energy Audit Project: What exactly an energy auditor does?

EnergyAuditing
http://www.asienergy.com/energy-assessment.html

One of my colleague yesterday (8/2) asked me what exactly an energy auditor do in energy audit project. It took a minute for me to answer that question because I did not involve directly into that project (I defined myself as expediter in this project, not as engineer. But since I am chemical engineer, I quite understand what we do in energy audit project).  About that question, I said an energy auditor does calculation of energy consumption per product, determine if the plant consumes too much energy or not, and give some recommendations to conserve energy. Is that an easy job? I don’t think so. It is not easy, but it’s simple. Read More