The potential of micro hydro generator embedded at 100,000 PE sewerage treatment plantTHIRI ZAW

CHAPTER 1 PAGEREF _Toc508031394 h 1
1.1Background of study PAGEREF _Toc508031396 h 1
1.2Problem Statement PAGEREF _Toc508031397 h 3
1.3 Objectives PAGEREF _Toc508031398 h 4
1.4Scope of Study PAGEREF _Toc508031399 h 4
1.5Significance of Study PAGEREF _Toc508031400 h 5
CHAPTER 2 PAGEREF _Toc508031401 h 6
2.1 Micro Hydro Power PAGEREF _Toc508031403 h 6
2.2Sewerage Treatment Plant PAGEREF _Toc508031404 h 8
2.3Potential of Micro Hydro in the Sewerage Treatment Plant PAGEREF _Toc508031405 h 9
2.4Theory of Hydropower PAGEREF _Toc508031406 h 11
2.5Basic Components of Micro Hydropower System PAGEREF _Toc508031407 h 13
2.5.1Penstock Pipe Selection PAGEREF _Toc508031408 h 13
2.5.2Turbines Selection PAGEREF _Toc508031409 h 14
2.5.3Generator Selection PAGEREF _Toc508031410 h 16
2.6Case Studies for Micro Hydropower System PAGEREF _Toc508031411 h 17
2.6.1A 200 kW Hydropower Plant in Puan Hydro, Korea PAGEREF _Toc508031412 h 17
2.6.2A Micro Hydro scheme at Sewerage Treatment Plant in Emmerich of Germany PAGEREF _Toc508031413 h 19
2.6.3A Small Hydroelectric Station for the new waste water treatment PAGEREF _Toc508031414 h 20
Plant in Amann of Jordan PAGEREF _Toc508031415 h 20
2.6.4A 1.35 MW Hydro Plant at the Point Loma Wastewater Treatment Plant PAGEREF _Toc508031416 h 21
2.6.5Other Case Studies of Multipurpose Schemes in Selected European Facilities PAGEREF _Toc508031417 h 22
CHAPTER 3 PAGEREF _Toc508031418 h 24
METHODOLOGY PAGEREF _Toc508031419 h 24
3.1Introduction PAGEREF _Toc508031420 h 24
3.2Preliminary Data PAGEREF _Toc508031421 h 24
3.2.1Flow rate of Effluent PAGEREF _Toc508031422 h 24
3.2.2Head of Effluent Discharge PAGEREF _Toc508031423 h 26
3.2.3Monthly Electrical Bill PAGEREF _Toc508031424 h 26
3.2.4Other Data PAGEREF _Toc508031425 h 28
3.3Summary of Methodology PAGEREF _Toc508031426 h 28
REFERENCES PAGEREF _Toc508031427 h 29

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CHAPTER 1INTRODUCTION1.1Background of studyHydropower is one of the renewable energy resource that can be derived from the falling water which may be harnessed for useful purposes. Hydropower is used initially to generate electricity. Water must be flowing water (kinetic energy) to generate electricity. Application of hydropower in the waste water begun with the treating of waste water in the Sewerage Treatment Plant (STP). The plant is divided into the few processes including the physical, chemical and biological pollutants (Mondal, 2015). Khopkar S. M. (2007) said that the main reason of the hydropower plant is to set up an eco-friendly environment with suitable management of sewerage treatment process so it will prevent pollution compared to disposing untreated waste water to the environment.

Sewerage is a liquid waste from industries, homes, offices, and others use that can also be includes rainwater which has run down from street during heavy rain or a storm. Sewerage water can contain inimical materials. It is a complicated mix of organic and inorganic nutrients, impurities, disease that cause bacteria and other microorganism and suspended solids. Hence, we need to treated the sewerage water before discharge to the rivers or seas. If we discharge untreated sewerage into rivers or sea, it will harmful to aquatic animals and plants.

In sewerage treatment plant, the treated sludge or the solid waste which is reasonable for disposal of reuse are normally handled as fertilizers (Wikipedia, 2016). Besides, the treated water which is not used for any other usage will discharge into the rivers or seas. Though, these can be applied in a high potential of hydropower application. Treated water of sewerage at a high pressure or flowing with a high velocity acquire of a high potential energy can be applied to run turbine or water wheel attached to generator so that we can generate electrical power (Archana Tamrakar, 2015).

Figure 1.1: Effluent Discharge Point at Juru STP11049003619500
Figure 1.2: Possible location of micro hydroelectric generator embedded at STP
Figure 1.1 shown the location of effluent discharge point at Juru STP and Figure 1.2 shown the possible location of micro hydroelectric generator embedded at STP
This research focus in a small-scale hydro scheme that generate up to 12 kilowatts ot target power. From this micro hydro generator, we can generate electricity by using the energy of flowing water and provides energy saving that can minimize the cost of electric bill for Sewerage Treatment Plant.

Juru Regional Sewage Treatment Plant (RSTP) was chosen for this research which is located at Jalan Kota Permai, Bukit Mertajam, Seberang Perai, Penang. This STP has design capacity of 150,000 PE.

1.2Problem StatementAll energy sources have some effect on our environment. Utilization of fossil fuel resources prompts global warming and environmental change. In many parts of the world little change is being made to moderate these changes. So, all energy like fossil fuels, coal, oil do substantially more harm than renewable energy sources by most measures, including air and water pollution, damage to public health, wildlife and habitat loss, water use, land use, and global warming emissions. One of the solutions is to use renewable energy resources that avoid from bringing impact to the environment. Most renewable energy sources include wind, micro hydro, tidal, geothermal, biomass and solar. This is why micro hydro is also use widely in recent years. The need to reduce the cost of energy used in the treatment of water and wastewater has grown as one of the major concern of the water industry over the last few years and it is expected to become more important in the near future. The main reason for this is because the water and wastewater industry are a heavy user of electricity.

1.3 ObjectivesThe purpose of this research is to identify the potential of micro hydro generator embedded at 100,000 PE sewerage treatment plant.

To determine the possible electrical power generated by the micro hydroelectric generator in kilowatts.

ii.To identify the Return on Investment (ROI) in terms of years or payback period based on saving on monthly electrical fees for application of micro hydro system in the operation of STP.

To identify the relative range in measurement of head of the micro hydroelectric generator and average of flow rate that can be suited to install in STP.

1.4Scope of StudyThis research focusing on identifies the requirements include optimum head and minimum flow rate to allocate the micro hydro generator in the effluent discharge of sewerage treatment plant (STP). However, this research does not discuss on the design of pipeline and turbine which acting as generator since the pipeline and turbine design has been fixed. Furthermore, this research only provides estimated capitals of investment for this system to be applied in STP due to the actual application in Malaysia are not implemented yet. The expected micro hydro power target is for 100,000 PE.

1.5Significance of StudyMicro hydro power is one of the renewable energy sources. Micro Hydropower is a method of generating electricity that uses moving water (kinetic energy) to produce electricity. Micro hydropower has been used as a common way of generating electricity in isolated regions since end of 19th century. Micro hydropower systems can be installed in small rivers, streams or in the existing water supply networks, such as drinking water or wastewater networks. In contrast with large-scale micro hydropower systems, micro hydropower can be installed with little or negligible environmental impact on wildlife or eco systems mainly because the majority of micro hydropower plants are run-of-river schemes or implemented in existing water infrastructure. Due to its versatility, low investment costs, and as a renewable energy source, micro hydropower is a promising option for producing sustainable, inexpensive energy in rural or developing areas. If the implementation of micro hydropower system is successful achieved, it can be contributing to a significant figure in term of cost saving for the electrical bill since the system can be facilitate in cutting down the expenses of electrical generation of the plant operation especially the consumption from aeration system.

2.1 Micro Hydro PowerMicro Hydro is actually an old though. Utilizing the fall of water to create power has been being used since 1885. Micro Hydro is a reliable source of power that can be use nearly anywhere. Micro hydro power is one of the simple power and renewable energy. Micro hydro is one type of hydroelectric power which can generates electricity from 5 kW to 100 kW by using natural water flow. Micro hydro can generate 100 standard units of electricity in one hour (Micro Hydro Power, 2003). In many areas which is highest in winter so there is minimum of solar energy when we can use micro hydro systems complement of solar PV power systems.
According to the Demirbas (2005), the division of hydropower based on the capacity is inconsistent over the hydropower literature and varies depending on the location. Micro Hydro power is generally having a power less than or equal to 100 kW (Hammad et al, 1994; Paish, 2002). Table 2.1 shown the classification of small scale hydro power
Station capacity  Unit capacity 
Micro hydro
Up to 100 kW  Up to 100 kW
Mini hydro
101 to 2000 kW 101 to 1000 kW 
Small hydro 
2001 to 25,000 kW  1001 to 5000 kW
Table 2.1: Classification of Hydro Power (Gaius-obaseki, 2010)
Moreover, hydropower can be divided by the capacity if installed, which include the large, medium, small, mini, and micro hydro power plants (Archana Tamrakar, et al. 2015). Besides, the subdivision of small hydro plants includes the Mini, Micro, and Pico hydro plants.
No Types of Hydropower Plant Description
1 Pico Hydro From a few hundred Watt up to 100 kW.

2 Micro Hydro From 5 kW up to 100 kW, usually provided power for a small community or rural industry in remote areas away from the grid.

3 Mini Hydro Above 100 kW, but below 1 MW either stand-alone schemes or more often feeding into a grid.

4 Small Hydro 1-15 MW usually feeding into a grid.

5 Medium Hydro 15-100 MW usually feeding a grid
6 Large Hydro More than 1000MW and usually feeding into a large electricity grid.

Table 2.2: Classification of Hydro Power Plant

Micro hydro systems are made from a number of components in general. According to S.U.Patel & Prashant.N.Pakale 2015; Big Fat Designs LLC 2016, the concept of micro hydropower is to utilize water pressure in generating the mechanical shaft by using a turbine and convert it into electrical power. Hence, we can get precious energy resources from the treated waste water through utilization in this system instead of discharging into the stream or rivers. Hydroelectric power is familiar large hydropower station that sometimes involve in the construction of major dams or a land flooded. Though, according to Guide (2004), micro hydropower system doesn’t need any assemble of dams or a land flooded. The oldest renewable energy techniques have been known to the mankind for electricity generation as well as the mechanical energy conversion thus the implementation of water falling from height has been utilized as a source of energy since a long time ago.

Archana Tamrakar, et al. (2015) stated that in the early 20th century, small scale hydropower was the most common way of electricity generating. A waterwheel on the Fox River in Wisconsin in 1882 that supplied power for lighting to two paper mills and a house was the first commercial use of hydroelectric power generating electricity (Vineesh V;A. Immanuel Selvakumar, 2012). Small hydro is the major supplier of the electricity from renewable energy sources in these days. For individual users who are independent of the electricity supply grid, small hydropower system related with small power sources are suitable for many reasons.

2.2Sewerage Treatment PlantTreating sewerage means removing contaminants from wastewater from household sewerage. Sewerage treatment process includes physical, chemical, and biological processes which is aim to remove theses contaminants and produce environmentally safe treated water called effluent. Effluent can prevent pollution compared to release the untreated water to the environment. Primary, Secondary and Tertiary treatment involves in treating of sewerage process.

In Malaysia, 38% of public sewerage treatment plants are mechanical plants. Mechanical plant is one type of sewerage treatment plant which operate using mechanical equipment that accelerates sewerage break down. In the future, Malaysia’s sewerage system will be made more efficient over the standardization of the types of plants used. As of Oct 2014 onward, the total public sewerage treatment plant in Malaysia is around 6966 plants. IWK (2014) stated that all the public sewerage treatment plants are available for the public usage around the population equivalent (PE) of 25,707,076. Table 2.3 shown the public sewerage treatment plants in Malaysia.

No Types of Sewerage Treatment Plant
As at Oct 2014 Population Equivalent
1 Imhoff Tank
679 507,648
2 Oxidation Ponds
403 1,681,176
3 Mechanical Plants
4,902 18,665,408
4 Network Pump Stations
982 4,852,844
6,966 25,707,076

Table 2.3: Public Sewerage Treatment Plants in Malaysia
2.3Potential of Micro Hydro in the Sewerage Treatment Plant
Hydroelectric power plants can generate electricity. Implementation of micro hydropower is becoming general in recent since it can provide reliability without require much maintenance and care. Archana Tamrakar, et al. (2015) stated that for available different head and flow rate of the waste water, output power has been expected. Producing of electricity from this way can be called as a profitable energy solution. Constructing small-scale hydropower system can be rated from $1,000-$20,000 which is around RM 3,900-RM 78,000 depending on the requirements of site electricity and location. According to the Archana Tamrakar, et al. (2015), only the initial investment cost is high but for the maintenance fees are relatively small compared to the other technologies. Thus, for long-term consideration, it will give profit in reducing the overall cost in future. Meanwhile, micro hydro is one of the renewable energy so it will also minimize the use of fuels not only improving efficiency on reducing cost.
1143000340169500Micro hydropower system in sewerage treatment plant can be dependable and without requires a large dam or a land flooded, it can provide constant electrical energy by utilizing waste water (R.K. Saket & Lokesh Varshney, 2012). Eslamian (2016) stated that generating power need only waste water from different parts of the city so there has almost zero environment impact. Treated effluent flowing at a high pressure with a high velocity through the utilization of turbine or waste water wheel coupled to generator can generate can generated electricity (Archana Tamrakar, et al., 2015). Implementation of micro hydro project in sewerage treatment plant is successful in the foreign developing country such as Korea, Germany, USA and other but Malaysia has not been fully adopted. So other foreign country which using a micro hydro system prove that utilization of micro hydro power possesses a great possibility to provide a sustainable and renewable energy in order to fulfill the public demand. It is hope that by using this renewable energy, micro hydro plants can provide power for hospitals, schools, homes and workshops in the future.

Figure 2.1: Process Micro hydro Flow in STP
2.4Theory of Hydropowerright1159510(1.0)
There are a few formulas to convert the hydraulic power to electrical power and to determine the required output power for generator. General equation to determine the flow rate, Q is multiplied by the average velocity, v and the product of the cross-sectional area, A of the connecting pipe between generator and sewerage treatment plant (STP):
Q=v × ?×D24
where D is the diameter of the connecting pipe and v is the velocity of effluent.

To determine the available amount of hydraulic power in the system:

Ph=Q×H×g×?The electrical power is converted as:
right247650 (3.0)
0 (3.0)

Pe=Ph×?=Q×H×g×?×?Ph is the theoretical hydraulic power and Pe is the electrical power outputs both have unit of Watts (W), and Q is the flow rate in unit of cubic meters per seconds (m³/s), H is the head in unit of meters (m), g is the gravitational constant in unit of meters per second square (9.81 m/s²), ? is the efficiency of turbine and generator which is unit less and ? is the density of water in unit of kilograms per cubic meters (normally use 1.0 kg/m³, depend on the temperature of water). The system will be able in contribution of endless power source once flow rate, Q and head, H in equations (2.0) and (3.0) are identified at their desirable values relative to meet the design requirement.

right476250 (4.0)
0 (4.0)
In hydropower plant the annual power generation, E in unit of kWh/year is determined from
where t is the operation of hours through a year.
According to Theophilus Gaius-obaseki (2010), the topmost turbines can maximize the efficiency from 80 percent to 90 percent while a micro hydro generator is possible to achieve from 60 percent to 80 percent of efficiency. Table 2.4 shown the estimated power referring to various head and flow rate of water (Archana Tamrakar, et al., 2015).

H Flow rate of water, Q (lps)
5 10 15 20 25 40 60 80
Power Output (W)
2 69 137 206 275 343 549 824 1099
4 137 275 412 549 687 1099 1648 2197
6 206 412 618 824 1030 1648 2472 3296
8 275 549 824 1099 1373 2197 3296 4395
10 343 687 1030 1373 1717 2747 4120 5494
14 481 961 1442 1923 2403 3846 5768 7691
20 687 1373 2060 2747 3434 5494 8240 10987
30 1030 2060 3090 4120 5150 8240 12361 16487
40 1373 2747 2940 5494 6867 10987 16481 21974
Table 2.4: Estimated power output referring to various head and flow rate of water (Archana Tamrakar, et al., 2015)
From the table, it can be said that to achieve the target power of 12 kW, the low flow rate of water 60 l/s or equal to 0.06 m³/s will required an extremely high head up to 30m of the height. Hence, it can be seen that requirement of the head for a low flow rate of water will need a very high head in term of the height of difference between the generator and discharge point.
2.5Basic Components of Micro Hydropower System
Sewerage tank, penstock pipe, turbine, generator for reliable operation of the system are the basic components of the micro hydropower system that can be applied to the Sewerage Treatment Plant (STP). Components selection is essential since the relevant components implemented in the system can minimize the cost of installation, boot up the output power and even maximize the efficiency of system.

2.5.1Penstock Pipe SelectionAccording to McMahon, (2016), a gate or sludge or intake structure which as a medium to control water flow or an enclosed pipe that allows water to flow towards a hydro turbines and sewerage systems is called a penstock and that term has been inherited from the early technology of watermills and mill ponds. Penstock is one of the components which can be costly in installation. While selecting the suitable penstock pipe, there are few considerations such as materials to use for a particular penstock design pressure including the roughness of the pipe’s interior surface, easy in installation, accessibility to site, effect in weather conditions, availability, method of joining, weight, suitable cost and possibility of structure damage (Archana Tamrakar, et al., 2015).

No Materials Friction Weight Corrosion Cost Jointing Pressure
1 Ductile ???? ? ???? ?? ???? ????
2 Asbestos Cement ??? ???? ???? ??? ??? ?
3 Concrete ? ? ????? ??? ??? ?
4 Wood Stave ??? ??? ???? ?? ???? ???
5 GPR ????? ????? ??? ? ???? ?????
6 uPVC ????? ????? ???? ???? ???? ?????
7 Mild Steel ??? ??? ??? ???? ???? ?????
8 HDPE ????? ????? ????? ?? ?? ?????
? = Poor, ????? = Excellent
Table 2.5: Comparisons of Penstock Materials
The pressure rating is the most important thing in selecting a penstock since the pipe thickness must be designed as maintain to withstand the maximum water pressure or there will be expose to a situation in which the risk of bursting (R.K. Saket ; Lokesh Varshney, 2012). The pressure of water in the penstock will directly influence by the head like the higher in the head, the higher in the pressure. The most commonly used materials for penstock are mild steel, high density poly ethylene (HDPE) and unplastified polyvinyl chloride (uPVC) because of their suitability, availability and approvability. Due to excellent performance such as minimum friction losses, least weight, resistant to corrosion, joining and pressure, the uPVC is the most common one compared to others. So selecting of penstock materials will be under consideration of the factors like friction, weight, corrosion, cost, joining and pressure. Since uPVC penstock has excellent performance, it has been widely used and utilized at sewerage power generation system and also has proposed for future work in this field.

2.5.2Turbines Selection
According to R.K. Saket ; Lokesh Varshney (2012), turbine is connected directly to the generator or connected aid of gears or belts and pulleys, depend on the requirement of speed for generator. Selection of turbine is depending on the firstly on the head and the design flow for the proposed micro hydropower installation and it is also affected by the suitable running speed of generator (Archana Tamrakar, et al., 2015). There are two main classes in turbines which are reaction turbines and impulse turbines.
Reaction turbines can be produced power by using the overwhelming force of moving water. Water flow over the runner as opposed to striking each blade individually since the runner is situated in the water stream. These types of turbines are suitable to applied in lower head and higher flow situations (Marissa Capua, et al., 2014). Reaction turbines include the Francis, Kinetic and Propeller turbines. Function of Francis is that water will released from above and around the runner which transferred to the filling of buckets and then whirling of runner. There are many types for Propeller turbines for example Kaplan turbines and Bulb turbines (micro turbines). Both turbines have a runner with three to six blades, and these blades are adjustable and keep contact with the water all the times (U.S. Department of Energy, 2014). But these two turbines are different in orientation. For low flow application, bulb turbines are usually used. These turbines can be integrated directly into horizontal flows meanwhile Kaplan turbines are placed vertically in the flow of water. Horizontal orientation assisted the turbines to be directly integrate into pipes with horizontal flow while vertical orientation contained the changing of the flow direction from horizontal to vertical.

On the other hand, another main type of turbine are impulse turbines. Utilization the velocity o flowing water to whirl the turbines blades and generation of electricity is the function of impulse turbines. Impulse turbines are suitable in high head and low flow applications (Marissa Capua, et al., 2014). Cross flow turbines and pelton wheels are type of impulse turbines. Cross flow turbines are constructed like a drum and operated a jet to discharge water opposite to the runner while pelton wheels generally have at least one free jet which will release the water into an area that fills the buckets of the runner. Cross flow turbines let the water to flow across the runner in two different time, firstly when the water flow from the outside to the inside of the blades and the secondly when the water flow from the inside to the outside of the blades. Cross flow turbines are suitable in higher flow and lower head than the pelton wheel (U.S. Department of Energy, 2014). Table 2.6 shown the head specifications for the impulse and reaction turbines.

Class Turbine Type Head Range (m)
Impulse Pelton Wheel 200 – 1800
Cross Flow 2.5 – 200
Reaction Francis 40 – 600
Kaplan 15 – 50
Bulb ; 30
Table 2.6: Head Specifications of Turbines (Marissa Capua, et al., 2014)
These head specifications were used to determine that which types of turbines can be used for different head. Form the table 2.6, it is seemed that bulb turbines will be suitable for application in this research.

Bulb turbines (micro turbines) which is generally used in low-head for head below 30 meters and flow rate from 2 MGD and 80 MGD. If the head is over 30 meters or flow rate is over 80 MGD, these turbines can be arranged into parallel to higher the flow or into series to greater effective head. There are different in turbines size to operate in a wide range o flow and head conditions which allow for high efficiency. To adjust the angle due to the flow variations, the runner blades have been designed. This make efficient in 94% for the turbines and generators (Voith Siemens Hydro Generation, 2014). Straight pipe for the water passage can simplified the construction work so these turbine-generator packages will benefit in low installation fess and simple maintenance.
2.5.3Generator SelectionAccording to Chapman (2004), there are two main types in generators which are synchronous and induction generators. There are some different between them. Generally, induction generators are uncomplicate, tough because it only needed minimal maintenance, present an inborn overload protection, and also size is small so it made them commonly applied in small power plants (H. Beltran, et al., 2014). But there are some shortcomings in the induction generator. Major disadvantage is that this generator relayed on the reactive power to function which is generally stabilized by installing a capacitors bank. On the other hand, synchronous generators are more efficient and can be easily adapted the load power factor alteration. But there are also disadvantages which are the operation at a constant synchronous speed and the requirement of rotor field DC excitation.

No Synchronous Generator Induction Generator
1 Construction Complicate Simple
2 Speed Control Not possible Possible though difficult
3 Starting Not self starting Self starting
4 Cost Costly Cheap
5 Maintenance Require frequent maintenance Cage motor are maintenance free
Table 2.7: Comparison between synchronous generator and induction generator
According to T. S. Bhatti, et al (2004), induction generators are suitable for micro hydro power generation. From the table 2.7, it is seemed that induction generator has many advantages compared to synchronous generator. According to the Archana Tamrakar, et al (2015), capacitors for excitation are generally in smaller systems to generate energy less than 10 to 15 kW and all generators must be driven at a steady speed to generate constant power at the frequency of 50 Hz. In two pore generator, 3000 RPM speed is too high for practical application in micro hydropower system thus four pole generator which has 1500 RPM is usually used (Archana Tamrakar, et al., 2015). Generator operates under 1000 RPM turn can be costly and bulky. It will require increasing in speed mechanism such as belt or gear box to make the speed of the generator to be compatible with the low speed of turbine. The type turbine-generator sets have advantages of lower fault level, less maintenance, simpler excitation system and lover capital cost for different sewage water heads so induction generator has been proposed for used and has been increasingly becoming more popular in micro hydropower system.

2.6Case Studies for Micro Hydropower SystemThere are discussion for a few cases of applications of micro hydropower in sewerage treatment plants in the world. One of the case is suitable to be used as reference for this research since power output is as small as 13 kW.
2.6.1A 200 kW Hydropower Plant in Puan Hydro, KoreaThe turbine generator unit is located in an underground power house which deliver water to a water treatment plant in this case and also provide electrical power to the facility as shown in figure 2.2 and 2.3 (Lau, 2008).

Figure 2.2: Water treatment facility
Figure 2.3: Dam feeding the facility
According to Lau (2008), this plant has turbine of 500mm Propeller type and generator with 200 kW power at 1200 RPM, head of 19.6m and flow of 1.18 m³/s. Figure 2.4 shown the propeller turbine used in this plant.

Figure 2.4: The 500 mm Propeller Turbine
2.6.2A Micro Hydro scheme at Sewerage Treatment Plant in Emmerich of Germany
This case is a very small hydro plant at a waste water treatment installation in Emmerich of Germany. In this plant, the output power generated is 13 kW and the generator is located at a water head of 3.6 m to 3.8 m with the water flow of 0.04 m³/s (400 lps) (Lau,2008). Thus this case is very similar with this research since output power is similar with the targeted output of this research.

Figure 2.5 shown the Asychrongenerator which is used in this treatment plant. This generator has a output of 15 kW, 400 V/50 Hz and the expected annual yield for this plat is 65,000 kWh.

Figure 2.5: Asynchrongenerator at Emmerich of Germany
2.6.3A Small Hydroelectric Station for the new waste water treatment
Plant in Amann of JordanAccording to Arab Countries Water Utilities Association (2012), water supply and sanitation is facing the problem of severe water scarcity in Jordan. Out of tenth countries, Jordan is considered as the most water stressed country (Andrew Maddocks, et al., 2015). Jordan is also one of the lowest levels of water resources in the world. Water-poor countries are the countries with a per capita water production below 1,000 cubic meters per year (Farzaneh Roudi-Fahimi, et al., 2002). According to Geo Factsheet (2010), there will be a minimum water availability per capita which fall from 200 m³ per person to 91 m³ per person in 2025. The depletion of groundwater reserves, high population growth and the impacts of climate change can go for bad to worse in the future. Thus, in the town of Amann of Jordan, a new wastewater treatment plant has been constructed. According to the Lau (2008), in this treatment plant, the main reason is to focus on the purification of water and the volume of water to be treated is 277,000 m³/day. In 2005, the engineers were appointed to construct the installation and they found a method to reduce the operation costs of installations. By turbining of wastewater upstream and downstream from the station, they targeted the annual power production of 21,9000,000 kWh. The company that constructed a new sewerage plant for Jordan has been offered to construct the sewerage treatment plant in Switzerland. The head of the sewerage treatment plant in Jordan is 55.7 meters.

The height different and the flow at Amann of Jordan, a sewerage treatment plant can produce more electricity than it consumes. Thus, this sewerage treatment can give a lot of opportunity to the engineers to discover the potential of micro hydroelectric installation. According to Lau (2008), this treatment plant decided to replace the dissipating valves with turbo generators to recover the excess pressure at the entry or at the outlet of the plant so it will allow for the generation of electricity. They tried to differentiate between two types of energy reconstruction. The raw sewerage is delivered from the town upstream into the sewerage plant and is turbines at the exist of the sewerage pipes in the first type. For the second type, the treated water from the plant is turbined at the discharge of a pipe or a stream or a river, such as conventional hydroelectric installation (Lau,2008).

In general, the sewerage treatment plants require a lot of electrical energy. For working the shifters, mixers, pumps, fans, etc. need a lot of electrical energy. That why the application of micro hydroelectric system is necessary to save the energy like Amann of Jordan.

2.6.4A 1.35 MW Hydro Plant at the Point Loma Wastewater Treatment PlantThe Point Loma Wastewater Treatment Plant is located at the Point Loma Peninsula in San Diego, California and it is a major wastewater treatment facility (Wikipedia, 2016). According to the Water Environment Federation (2007), after a 27 m fall from the plant to the outfall, through a 7.2 km ocean outfall, effluent is discharged into the ocean. Hydroelectric plant grabs the energy around 1,350 kW of the effluent since it falls down the outfall connection (United States Government Accountability Office, 2010). 1.35 Megawatts is the energy which is sufficient to generate power for supplying energy t0 10,000 homes (The City of San Diego, 2002). This treatment plant which started in 1963 can treat the sewerage of 662,000 m³/day from a 1,165 km² area of more than 2.2 million residents in 12 municipalities. According to the City of San Diego, 2002), this plant is a 16 ha site on the Point Loma bluffs in San Diego and the advanced primary treatment plant has a capacity of 908,400 m³/day.

According to the Water ; Wastes Digest (2001), the Point Loma hydroelectric turbines were forced to shut down in 1989 and partially disassembled due to the failure of properly regulate the sewerage flow. However, modifications of piping system in combination with enhancements in the ocean outfall’s hydraulic characteristics and also the growing rate of energy created a renewed interest in carrying the project back on-line (Water & Wastes Digest, 2001).

2.6.5Other Case Studies of Multipurpose Schemes in Selected European FacilitiesEuropean countries including Poggio Cuhoulot of Italy, Armary of Switzerland, Sangüesa of Spain, Llys y Fran of Scotland and Marchfeldkanal of Austria can offer a reasonable output power under range of below 100 kW of micro hydro power produced in high in gross head or high in the nominal discharge (Aline Choulot, et al., 2014).

Table 2.8 below shown the selected European case studies of multipurpose schemes (ESHA et al., 2010). Irrigation network, Sangüesa of Spain and Marchfeldkanal of Austria are available with high nominal discharge from 1.16 m³/s to 6.00 m³/s although they are least in gross head from 2 meters to 11 meters. The rest possess of electrical output under 100 kW are higher in gross head from 25 meters to 105 meters although they are lower in nominal discharge from 0,09 m³/s to 0.38 m³/s.

Existing Infrastructures Power Plant Name and Country Nominal Discharge (m3/s) Gross
head (m) Electrical
(kW) Electrical
Drinking water
network La Zour, CH 0.30 217 465 1.8
Mühlau, AT 1.60 445 5750 34.0
Poggio Cuculo,
IT 0.38 28 44 0.36
Irrigation network Armary, CH 0.09 105 68 0.45
AT 6.00 2 70 0.50
Rino, IT 0.78 446 2800 14.00
Raw wastewater
network Le Châble,
Profray,CH 0.10 449 380 0.85
network Seefeld, AT 0.25 625 1192 5.50
Nyon, CH 0.29 94 220 0.70
Hydropower dam
and reserved flow Llys y Fran, UK 0.16 25 29 0.22
Le Day, CH 0.60 27 126 0.58
Hydropower dam
and fish pass Aire-la-Ville, CH 2.00 21 348 2.72
Navigation lock L’Ame, FR 10.80 2 145 0.65
Desalination plant Tordera, ES 0.11 685 720 –
Cooling system Sangüesa, ES 1.16 11 75 0.50
Skawina, PL 23.30 8 1560 6.39
Table 2.8: Selected European case studies of multipurpose schemes (ESHA et al., 2010)

CHAPTER 3METHODOLOGY3.1IntroductionThis research focus on the potential of micro hydro generator embedded in 100,000 PE sewerage treatment plant. Sewerage treatment plant selected for this research is Juru Regional Sewerage Treatment Plant which is under Indah Water Konsortium Company (IWK) and located in Jalan Kota Permai, Bukit Mertajam, Seberang Perai, Penang. Site Visit has been explored to get the preliminary data consist of the flow rate of effluent, population equivalent (PE) that handle by this STP, effluent discharge point, monthly electrical bill of the plant and another important data that need for this research.

3.2Preliminary Data3.2.1Flow rate of EffluentThe data for the flow rate of effluent is for recent months from January 2016 until September 2017 which is shown in Table 3.1. The flow rate of effluent is in cubic meters per second (m³/day) to calculate the possible output power generated in STP. The flow rate of effluent is necessary to determine the calculation of possible output power generated by the micro hydro generator. Further calculation in the next chapter, the average value of effluent flow rate is computed. The detail of effluent floe rate data is described in Appendix.

Year Month Flow rate of Effluent (m3/month)
2016 January 567,088
February 492,039
March 397,343
April 424,972
May 793,449
June 633,501
July 576,026
August 541,729
September 871,154
October 826,763
November 1136,084
December 823,031
2017 January 892,744
February 546,671
March 605,523
April 665,987
May 709,558
June 565,364
July 539,062
August 630,409
September 953,635
Table 3.1: Monthly Flow Rate of Effluent (m³/month)3.2.2Head of Effluent Discharge
Measurement of optimal vertical height, in meters from the stream or river up to the point where the effluent discharge is called the head of effluent discharge. Head of effluent discharge is necessary for the possible output power generated from the micro hydro generator install in STP. From the data collected form Juru STP, the head of effluent is at 1 m. Juru STP used this value to design the head measurement for their STP facility. The head of effluent discharge can be different in other STP based on their design consideration. Though, for the calculation of power output, this research only focuses in the value given from the Juru STP.

3.2.3Monthly Electrical BillThe monthly electrical bill with respects to the electrical energy consumption from January 2016 until September 2017 for the Juru STP is shown in the Table 3.2. The electrical bill is in Ringgit of Malaysia (RM) with refer to the total electrical energy consumption of the STP plant in kilowatt per hour (kWh). The calculation of the payback period or Return on Investment (ROI) is calculated based on the possible power output and the monthly electrical bill. For further calculation, an average of electrical energy consumption and also the average of monthly electrical bill is computed. The data for the monthly electrical consumption and monthly electrical bill from Juru STP is shown in Appendix.

Year Month Electrical Energy Consumption (kWh) Monthly Electrical Bill (RM)
2016 January 238,540 89,396.47
February 211,239 81,739.82
March 218,004 86,101.75
April 210,232 130,424.00
May 233,475 87,212.07
June 197,577 76,175.09
July 176,449 74,425.12
August 208,482 80,232.00
September 207,510 82,929.70
October 220,785 82,788.00
November 239,907 87,662.60
December 222,334 84,092.45
2017 January 222,334 84,092.45
February 148,611 61,116.85
March 183,248 68,959.70
April 192,098 73,233.60
May 213,867 80,670.40
June 181,849 70,099.20
July 181,478 70,521.30
August 197,511 77,347.00
September 214,004 83,403.25
Table 3.1: Monthly Electrical Bill (RM) with respects to Electrical Energy Consumption (kWh)3.2.4Other Data
Other data that need for this research, obtained from Juru STP, included density of effluent, efficiency of turbine and population equivalent (PE). Where;
Density of effluent in this STP is 1000 kg/m³.

Efficiency of turbine is assumed to be 0.85.

Population equivalent that served by Juru STP is maximum value of 150,000 PE but normally they served around 100,000 PE.
Proposed a research study at Juru RSTP
Preliminary data collection and plant visit
Power output calculation based on preliminary
Calculation of ROI/payback period based on the power output calculated
Result analysis
Proposed a research study at Juru RSTP
Preliminary data collection and plant visit
Power output calculation based on preliminary
Calculation of ROI/payback period based on the power output calculated
Result analysis
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