ANALYSIS OF THE DESALINATION TECHNOLOGY WITH REVERSE OSMOSIS MEMBRANE IN TIDAL MARSH WATER TREATMENT A REVIEW

ANALYSIS OF THE DESALINATION TECHNOLOGY WITH REVERSE OSMOSIS
MEMBRANE IN TIDAL MARSH WATER TREATMENT: A REVIEW
Milena Amalia1, Nopi Stiyati Prihatini2
Environmental Engineering, Faculty of Engineering, Lambung Mangkurat
University, Jl. Jend. A. Yani KM. 36, Banjarbaru, 70714, Indonesia
E-mail: [email protected]
ABSTRACT
Coastal areas and small islands are Often faced with the provision of clean water and it is
causing problems in lack of drinking water. The water resources on the area have bad quality,
like the Brackish groundwater is salty or Because It contains very high levels of salt or TDS
(Total Dissolved Solid). One of the ways to Overcome the problems known as Brackish water
desalination, the which is to separate the freshwater from saltwater. There are Several
methods known as desalination process technologies, one of the which is by using reverse
osmosis or electrodialysis. Osmosis principle behind this is to give the solution pressure, who
has a high salt content (concentrated solution) to enable the flow of water molecules toward a
solution with low salt concentration (dilute solution). Based on the results of Several studies,
the reverse membrane system can reduce salt levels up to 95-98%. The quality of processed
water treatment unit water reverse osmosis system is quite good and you can drink without
boiling.
Keywords: Brackish water, desalination, reverse osmosis.
I. INTRODUCTION
Fresh water is a very important source of water for people living in coastal areas and
tidal marsh. Tidal wetlands formed a result of increased sea surface that carries sediment
and the flow of a river that flows into the sea, then deposited in the area around the beach.
During the dry season, people living in the area around the beach and tidal often
experience water shortages. Rainwater that is a source of water that had been prepared in
the rain water tank (PAH) can not even be sufficient for the dry season. And we all know
that the real source of sea water and tidal water is so abundant. However, the fact remains
that there are many residential areas in coastal areas of water shortage.
Wetlands which are located around the flood plains of coastal areas such as tidal
swamp land formed due to an increase in sea surface that carries sediment and or the flow
of a river that flows into the sea, then deposited in the area around the beach. Source
saltwater / brackish abundant quantity would be better if it can be processed into fresh
water. Therefore, there are many methods to treat saltwater / brackish into freshwater such
as distilling, filtration, ionization (ion exchange) and desalination. Desalination is a
separation process which is used to reduce the salt content of the water soluble salt to a
certain level so that water can be used (Hermayanti, 2011).
Saltwater or brackish water is a solution containing multiple types of solutes such as
salts, of which an average of 3 to 4.5%. Desalination means the separation of fresh water
from salt water. The methods used in this process is called desalination of salt water. In the
separation of fresh water from salt water, there are several desalination process
technologies that have been widely known among other things, that porses distillation or
evaporation process technology using membranes, ion exchange processes, etc. (Said,
2003).
Desalination is a separation process that aims to reduce the salt content of the water
soluble salt so that the water can be used. The raw water is bad, such as the chloride with a
high TDS, requires processing system with Reverse Osmosis (RO). RO systems using
micro-scale filtration (molecular), which is conducted through an element called
membrane. With this RO system, the high chloride and TDS can be reduced or eliminated
altogether. An important requirement that must be considered is the quality of the water
that comes into the membrane element must be free of iron, manganese and organic matter
(organic color). Thus the RO system in general are always equipped with adequate
pretreatment to remove impurity elements, such as iron, manganese and organic dyestuffs
(Herlambang, 1999).
There are two basic systems for desalination, which is distilled through evaporation
and filtration through a special membrane that can prevent passing the salt molecules. The
process of desalination by distillation system and the separation of fresh water by changing
the water phase, whereas the separation membrane system with fresh water from brackish
water by way of pressure using reverse osmosis membranes (reverse osmosis) or by
electrodialysis. The product is generally a water desalination process with the dissolved
salt content of less than 500 mg / l, which can be used for domestic purposes, industrial,
and agricultural (Hermayanti, 2011).
Water treatment plant with reverse osmosis system is designed in accordance with the
socio-economic level as well as community drinking water needs stempat. Brackish water
treatment plant with reverse osmosis system is a series of the complete process, but
packaged in a simple form that can be developed for other -location locations that have the
same quality of raw water sources (Widayat, 2018).
II. RESULTS AND DISCUSSION
In this process the salt molecules can not pass through the semipermeable membrane,
so that only water molecules flow occurs only. Through this process, we will get pure
water produced from a solution of high salt content. This is the basic principle of reverse
osmosis systems. Based on this, the reverse osmosis system, it takes a minimum of two
components, the high pressure (high pressure) and a semi-permeable membrane. There are
three streams of fluid in the desalination process, which feed in the form of salt water (eg
water tidal marsh), a product which has a lower salinity, and the concentrate has a high
salinity. In regard to mengasilkan freshwater,
When given the pressure on the side of a solution having a high salinity (concentrated
solution), then there is a process called reverse osmosis. During the process of reverse
osmosis, the water molecules flow through a semi-permeable membrane, but at the same
time restrained salt molecules in the left carrier for salt molecules are not able to pass
through a semi-permeable membrane. Therefore, after some time, a reduction in the
volume of water in the container to the left, while the amount of salt remains the same.
This resulted in the concentration of salt has increased sharply.
In experiments with a reverse osmosis system to research by (Said Nusa Idaman,
2003) used Reverse Osmosis unit with a capacity of 10 m3 / day which is the heart of the
overall water treatment system. This unit consists of a membrane spirally wound
membrane with a protective outer shell (vessel) that is resistant to high pressure.
In this research method used was a combination of coagulation-flocculation process,
the oxidation of iron and manganese, filtration and desalination by reverse osmosis
systems (RO). After going through various processes and then through a filter cartridge,
the water supplied to the RO membrane unit using a high pressure pump and
simultaneously injected with an anti-crust (antiskalant) and an anti-biofouling. The water
coming out of a reverse osmosis membrane module is fresh water and waste water which
has been concentrated salt. Further product fresh water supplied to the water storage tank.
The byproduct of desalination is brine. Brine is highly concentrated salt solution (greater
than 35,000 mg / l of dissolved salts). The reject brine discharged into the channel or into
the swamp back. The quality of processed water treatment unit reverse osmosis water
system is very good and you can drink without boiling. From the description above it can
be seen that in order to cultivate swamp or suangai brackish water into potable water that
can be done with a combination of coagulation - flocculation, precipitation, filtration and
reverse osmosis processes that are equipped with UV sterilizer. Reverse osmosis
membrane systems can lower the salt content of up to 95-98%.
From the results of research by (Herlambang, 1999), factors that affect the size of the
osmotic pressure is the salt concentration and temperature of the water. Generally, sea
water contains a minimum of 30,000 ppm TDS. RO systems can not filter out salt
completely up to 100%, the water still contains a little salt production. To get the water
with little salt content then applied to a system with two or three channels. If you want to
make drinking water containing approximately 300 to 600 ppm TDS simply use a single
channel. If the treated water produced become more and more the amount of raw water
will become larger and as a result the required pressure will be even greater. Artificial
pressure (working pressure) must be greater than the osmotic pressure in the raw water.
Pressure of work required when using sea water is between 55 and 70 kg / cm2. Here is the
result of water treatment RO systems
(Herlambang, 1999).
Based on the results of the study (Widayat, 2018), reverse osmosis should have certain
requirements, such as turbidity should be zero, levels of iron and manganese must be <0.1
mg / l, pH neutral and should always be controlled in order to prevent coking and other
calcium carbonate. Brackish water treatment by reverse osmosis system in this experiment
consists of two parts, namely the initial processing unit (Pretreatment) and the advanced
processing unit (Treatment), ie reverse osmosis unit. Raw water that is brackish need to do
the initial processing before being processed in a reverse osmosis unit because it still
contains particles of suspended solids, mineral, and other plankton. Preliminary processing
unit consists of several major equipment ie raw water pumps, dosing pumps are equipped
with chemical tanks, tank reactor (contactor), filter sand, filter manganese zeolite, and a
filter for the removal of color (color removal) or activated carbon filter, and the filter
cartridge size of 0.5 lm. While the advanced processing unit consists of a high-pressure
pumps, reverse osmosis membranes, dosing pump anti crust ingredients (anti scalant) and
antifungal (anti biofoaling) equipped with chemical tanks and sterilizer ultra-violet (UV).
Results from this research that the water from the processing of these RO IPA can be drunk
directly without the need to be cooked first, with processing costs per liter of drinking
water from the raw water is Rp. 18.36 where the bottled water currently reaches Rp. 1,500
per liter. Other common benefits of research on water management with a reverse osmosis
system is an increase in people's lives,
III. CONCLUSION
By using the method of desalination, seawater or brackish water that is processed by
reverse osmosis (reverse osmosis) is converted into clean water so that it can deal with the
crisis of water supply for the communities. Utilize sea water as clean water also can
prevent soil degradation that can occur at any time if we continue to use groundwater.
Direct application of water treatment technology brackish reverse osmosis systems (reverse
osmosis) is beneficial for the local community because it can obtain safe drinking water
and meets the requirements for drinking water at a price much cheaper than bottled water.
Units of reverse osmosis water treatment systems (reverse osmosis) and can be drunk
directly is potentially an attempt to overcome the problem of drinking water supply for
hard water areas such as in coastal areas or tidal marsh.
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Herlambang, Arie & Robertus Hayoko.(1999). Pengolahan Air Asin atau Payau Dengan
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Fakultas Pertanian Universitas Bengkulu, Bengkulu.
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