Identifying opportunities to cultivate algae combined with wastewater recycling as a source of ...

79 Pages·2014·2.22 MB·English

Identifying opportunities to cultivate algae combined
with wastewater recycling as a source of renewable
energy in Southeast Asia

Marcus Tang

Murdoch University
School of Engineering and Information Technology
Master of Science in Renewable Energy
2014
Declaration

I declare that, apart from properly referenced quotations and citations, this
dissertation is my own work and complies with Murdoch University's academic
integrity commitments and any other conditions of submission as attached to the

dissertation. It has not been submitted previously for assessment in another unit.

Signed: Marcus Tang
Abstract
Water and energy are finite resources and our demand for these resources shape the world.
The world’s population has access to only 0.007% of the total water on earth for
consumption and close to 1.3 billion people do not have access to electricity. With the vast
majority of the world’s population moving into urban areas, the need to develop the
infrastructure and protect the resources that ensure the safe and stable access to water and
energy is paramount. This is especially so for developing countries where access to these
resources are critical in the alleviation from poverty.

Cities use large amounts of water and energy to sustain its growth, while producing large
amounts of waste and wastewater. If these pollutants are not treated, it can cause serious
health problems to the population. Therefore, coupling wastewater treatment with microalgae
could be the solution. Algae, which is known as a “third generation biofuel”, offers many
benefits over other biomass resources, such as shorter cultivation time, flexibility in types of
biofuels, producing high yields and most importantly the ability to treat pollution. However,
high production cost is one of the major challenges facing the industry.

The research paper explores the feasibility of microalgae production with wastewater
treatment and the possibility of coupling wastewater treatment with microalgae production as
a solution to create a reliable stream of renewable energy production.

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Contents
1 Introduction .................................................................................................................................... 7
1.1 Aims and Objectives ............................................................................................................ 9
1.2 Research Questions ............................................................................................................ 9
2 WATER & ENERGY .................................................................................................................. 10
2.1 Scarcity of freshwater resources ...................................................................................... 10
2.2 Increase in water demand ................................................................................................. 11
2.3 Access to Energy ............................................................................................................... 11
2.3.1 Renewable Energy in Asia ........................................................................................ 12
3 Wastewater ................................................................................................................................. 13
3.1 Wastewater Treatment Process ....................................................................................... 14
3.1.1 Preliminary treatment ................................................................................................. 16
3.1.2 Primary treatment ....................................................................................................... 16
3.1.3 Secondary Treatment ................................................................................................ 17
3.1.4 Tertiary Treatment ...................................................................................................... 19
3.1.5 Disinfection .................................................................................................................. 20
3.2 Advantages and disadvantages of conventional wastewater treatment .................... 21
3.2.1 High energy consumption and cost ......................................................................... 21
3.2.2 Loss of valuable nutrients and cost of sludge treatment ...................................... 21
3.2.3 Secondary pollution.................................................................................................... 22
4 Phycoremediation ....................................................................................................................... 23
4.1 Microalgae ........................................................................................................................... 23
4.2 Microalgae used in wastewater treatment ...................................................................... 25
4.3 Challenges of coupling microalgae with wastewater treatment .................................. 25
4.4 Advantages of microalgae wastewater treatment over conventional treatment ....... 26
4.4.1 Removal of nutrients .................................................................................................. 26
4.4.2 Removal of pathogens ............................................................................................... 27
4.4.3 Photosynthetic aeration ............................................................................................. 28
4.4.4 Removal of heavy metals .......................................................................................... 28
4.4.5 Reductions in sludge formation ................................................................................ 29
4.4.6 Green House Gases reduction and CO2 mitigation ............................................. 30
4.4.7 Removal of coliform bacteria .................................................................................... 30
4.4.8 Lower energy requirement and cost ........................................................................ 30
4.4.9 Production of useful biomass ................................................................................... 31
5 Cultivating Microalgae in Wastewater ..................................................................................... 32
5.1 Factors affecting growth of microalgae ........................................................................... 33
5.1.1 Climate conditions ...................................................................................................... 33
5.1.2 Carbon Dioxide ........................................................................................................... 34
5.1.3 Evaporation and salinity ............................................................................................ 35
5.2 Microalgae for biodiesel production ................................................................................. 35
5.3 Microalgae for bioethanol production .............................................................................. 37
5.4 Summary ............................................................................................................................. 38
5.5 Waste stabilisation ponds ................................................................................................. 38
5.5.1 Facultative treatment ponds ..................................................................................... 38
5.5.2 Maturation treatment ponds ...................................................................................... 40
5.5.3 High rate algae ponds................................................................................................ 40
5.6 Photobioreactors ................................................................................................................ 41
5.7 Hybrid two stage production system ............................................................................... 42
6 Southeast Asia (SEA) – Vietnam as a Case Study .............................................................. 43
6.1 Water and wastewater ....................................................................................................... 43
6.2 Energy profile and renewable energy potential ............................................................. 44
7 Economics ................................................................................................................................... 46
8 Wastewater treatment with biorefinery .................................................................................... 50
8.1 Biorefinery ........................................................................................................................... 50
8.2 Conceptual model of wastewater treatment with biorefinery ....................................... 51
8.2.1 Preliminary removal and primary treatment ........................................................... 51
8.2.2 HRAP and wastewater treatment ............................................................................ 52
8.2.3 Harvesting ................................................................................................................... 52
8.3 Recycling of nutrients and CO ........................................................................................ 54
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8.4 Processing of microalgae .................................................................................................. 54
8.5 Extraction of microalgae oil ............................................................................................... 55
8.6 Biofuel processing .............................................................................................................. 55
8.6.1 Transesterification ...................................................................................................... 56
8.6.2 Direct transesterification ............................................................................................ 58
8.6.3 Fermentation ............................................................................................................... 58
8.6.4 Anaerobic Digestion ................................................................................................... 59
9 Conclusion and Recommendation ........................................................................................... 62
9.1 Research Limitations ......................................................................................................... 63
9.2 Follow-up Research ........................................................................................................... 63
10 Bibliography............................................................................................................................. 64
1 Introduction
Energy is an essential driver in economic progression with access to energy playing an even
more important role in developing countries, where reliable energy can alleviate the
population from poverty (UNDP, N.D) and provide economic and social stability. As the world
continues to battle with changes to our climate caused by our demand for energy (EPA, N.D)
and depletion of our fossil fuels resources, the need to develop reliable and sustainable
renewable resources has come to the forefront in the bid to sustain our current way of life.
There is currently close to 7.2 billion people living on Earth and this number is projected to
hit 9.6 billion by 2050 (DESA, 2013). The World Health Organisation (WHO) has projected
that by 2030, 60% of the world’s population will be living in a city with the number reaching
70% by 2050 (WHO, n.d). Similarly, by 2030 close to 55% of Asia will be living in urban
areas (ADB 2011, 17). Populations in developing countries will see the greatest increase,
according to the United Nation (UN) as rural populations move to the cities in search of
better job opportunities to improve their standard of living (World Bank, n.d). The group of
people that suffers the most are the urban poor, who live in poverty and lack access to basic
necessities (UN, 2014). It is estimated worldwide that there are one billion people living in
such urban slums (UNFPA 2007).

According to the UN it is estimated that are around 1.1 billion people across the world that
do not have access to improved water supply sources and 2.5 billion people have no access
to proper sanitation facilities (UNDESA, N.D). Access to safe drinking water is a basic right
and is recognized by the UN in its Millennium Development Goals (MDGs), but the most
affected continue to be in developing countries where communities live in extreme poverty
with little access to proper sanitation and clean drinking water. The implementation of a
reliable wastewater management system in urban areas is thus a necessity, with the lack of
proper wastewater management curtailing poverty reduction and diminishing overall health.
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However, the challenge is that the cost of wastewater treatment plants can be high (UN
Habitat 2010, 27).

Whilst cities require large amounts of water and energy to sustain its growth, they also
produce large amounts of waste and wastewater. Therefore, combining the treatment of
wastewater with the production of renewable energy can address many of the challenges
facing larger scale adoption of renewable energy whilst adding value to the water treatment
process. As such, alternative sources of sustainable energy can provide energy security and
further help the development of the country. Algae, specifically microalgae, can be that
alternative source of energy for developing countries. Known as a “third generation biofuel”,
microalgae offer many benefits over other biomass resources, such as shorter cultivation
time, flexibility in types of biofuels and producing high yields. However, the current
technology and high production cost are some of the major challenges facing the industry.

For this research, Vietnam was chosen as the country to evaluate the potential of cultivating
microalgae combined with wastewater treatment. Vietnam is located in Southeast Asia
(SEA), a region comprising 11 countries with a combined population of over 600 million and
is one of the fastest growing markets in the world. A majority of these countries are in the
early stages of development except for Singapore that has a matured economy. Economic
growth can come at a cost to the environment and the community with increased industrial
and urban development. These developing economies face a larger proportion of their rural
population moving to the cities in search of better opportunities. This large urban migration
puts additional stress on their underdeveloped water and energy infrastructure. Choosing
Vietnam as a case study is based on the assumption that projects implemented in Vietnam
have similar potential for success in other developing countries of SEA due to the similarities
in their economic development. This is not taking into account the political and social aspect
in the decision process.
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1.1 Aims and Objectives
The aim of this research is to explore the feasibility of microalgae production with
wastewater treatment plant.

The objective is to evaluate the possibility of coupling wastewater treatment with microalgae
production as a solution to create a reliable stream of renewable energy production whilst
providing a public service of treating wastewater.

1.2 Research Questions
The economic viability of cultivation and harvesting of microalgae is hampered by the high
cost associated with the use of available technology and processes. There is a lack of
information available in the literature on the economic viability of a commercial algae biofuels
facility due to the lack of projects and publicly available data. As such, the research aims to
address the following research questions:
 Is cultivating microalgae with wastewater a viable solution?
 Can a microalgae wastewater treatment facility address the cost challenges to
increase renewable energy generation?

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2 WATER & ENERGY
Water and energy are interdependent with actions in either domain greatly affecting the
other. Without energy it would be very difficult to bring drinkable water to the population, and
without water mass energy cannot be generated. It has been estimated that close to 7% of
the total global energy generation is used in the extraction, treatment and transportation of
water (Hoffman, 2011) with the number rising to 40% in developed countries (WEF 2009, 3).
Conversely, water is critical in the generation and transmission of energy. Close to 90% of
power generation is water intensive (UN Water 2014, 33), as water is required to cool the
steam that spins the turbines (UCS, 2011).

2.1 Scarcity of freshwater resources
Water is what sustains life on earth.
Close to 70% of the earth is covered
with water, but only a small fraction of
about 3% is made up of freshwater
with the remaining comprised of salt

water in the oceans (National
Fig 1: Global water stress and scarcity of water (UNEP,
Geographic, N.D; USGS, 2014).
2008)
Within this small fraction, a large proportion of around 70% is locked in ice caps and glaciers
leaving only 0.007% of the total water on earth available for consumption (USGS, 2014;
UNEP Freshwater resources, N.D). This makes groundwater the primary source of
freshwater followed by surface water bodies such as lakes, reservoirs and rivers (UNEP
Freshwater resources, N.D). A sad fact is that much of this groundwater is non-renewable
and will be mined to exhaustion if we continue at this high rate of consumption.

As the world’s population continues to expand, our finite water resources will be placed
under further strain. The UN has projected that by 2025 there will be close to 1.8 billion
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