The Decrease of Organic Substance Concentration (KMnO4) and Turbidity in Well (Ground) Water Using Biosand Filter Reactor
The main source of water options in most urban and rural areas for Samarinda was well (ground) water. Samarinda is a developing city and most highly populated located in the East Borneo province of Indonesia. Meanwhile, the location and characteristic of land in Samarinda was swampy areas with organic substances concentration (KMnO4) and high turbidity, a poor drinking quality to might have health problem. In this study established potential of BSF for efficiency removal organic substances concentration (KMnO4) and turbidity. (Unit biosand filter was made from 8 mm rectangular glass with the medium used inside BSF reactor as sand local, gravel and supported by aerator for supply O2 to growing biofilm at the layer of fine sand and also diffuser plate to maintain the flow rate of water into the BSF reactor unit. Then, BSF was using flow rate (0.2 and 0.4 m h-1) and paused period (6 and 12 h). Efficiency decrease in the concentration of organic substances, the fist biosand filter the average efficiency by 76.82%, the second biosand filter average efficiency of 74.17%, at the third biosand filter efficiency by an average of 71.28% and the fourth biosand filter average reduction efficiency is 73.29% and while the turbidity of the average efficiency for the first biosand filter by 96.56%, the second filter biosand average efficiency of 94.08%, the third biosand filter average efficiency amounted to 96.52% and the fourth biosand filter average efficiency of 95.03%. Significant impact of this study was conducted The BSF design, construction, operational and maintained as technology become solution in urban and rural area to provide safe water and drinking water in developing countries.
Received: April 13, 2012;
Accepted: June 05, 2012;
Published: August 23, 2012
Waterborne diseases are the main cause of sickness and death in the community
with limited access to safe drinking water. And about 80% of infectious diseases
in the world are water-borne (Xia et al., 2004).
World Health Organisation estimated that worldwide, 1.8 million losses arise
per year due to lack of hygiene and poor water value (WHO/UNICEF,
Drinking water polluted by microorganisms can cause dozens of communicable
disease in developing countries (Arnal et al., 2001).
Currently, boiling water is regularly used in several countries as a disinfection
technique, however its high cost is a main concern (Sobsey,
2002). There are several methods for water treatment for consumption, including
granular activated carbon, anaerobic digestion, coagulation, flocculation, chemical
oxidation, membrane separation, electrochemical treatment, filtration, flotation,
softening, hydrogen peroxide catalysis and reverse osmosis (Alade
et al., 2012; Alaboud and Magram, 2008; Magram
and Abdel-Azeem, 2008; Bhattacharya et al., 2008;
Durai and Rajasimman, 2011; Gokturk
and Kaluc, 2008; Ibeto et al., 2010; Magram
and Azeem, 2008; Ramalakshmi et al., 2012).
However, in poor countries infrastructure and supply of water frequently require
suitable management and regulation in the rural communities (Pryor
et al., 1998). Weedy institutional agreement, lack of financial income
and poor practicable understanding hider a feasible water systems (Lenton
and Wright, 2004; Momba et al., 2005). Financial
ability of centralized drinking water management systems are extremely essential
in the sparsely settled rural populations and it is furthermore practicable
that the fashion is changing in the direction of decentralized solutions in
these cases (Peter-Varbanets et al., 2009). The
World Health Organisation suggested point-of-use household water treatment (POU)
as an involvement to discuss need, illustration on inexpensive technologies
(Sobsey, 2002; WHO, 2007).
A current evaluation point-of-use household water treatment (POU) choice in
developing countries use Slow Sand Filter (SSF), generally called the biosand
filter (BSF) where improved water supplies are often difficult and costly to
develop, operate or support (Sobsey et al., 2008).
The BSF was modified for household application from traditional Slow Sand Filter
(SSF), making the construction more appropriate for household use (Ahammed
and Davra, 2011). In conventional SSFs, during the ripening process a biolayer
(schmutzdecke) forms, head loss increases and performance improves. Since the
filter is generally charged once daily, a portion of the charged water remains
in the BSF until the next charge. It was reported that about 143,000 BSFs were
in operation as of June 2007, serving an estimated 858,500 users in 36 countries.
For that year, they produced nearly 1.3 billion liters of drinking water (at
25 L/unit/day) (Clasen, 2009). Famous biosand filters
are mainly know as an efficient method between the five dissimilar household
treatment technologies and as having the most prospect of becoming widely used
and sustainable for improving household water quality to decrease waterborne
disease and death (Sobsey et al., 2008; Stauber
et al., 2009). Slow Sand Filter (SSF) can reduce 90-99% bacteria,
iron (Fe), manganese (Mn) 30-90%, BOD 46-75%, COD<15-25%, pesticide 0-100%,
turbidity<1 NTU, Giardia cycts and virus 99% (Smet and
van Wijk, 2002).
The biosand filter is a water purification process where the water is treated
on a medium with low-speed process that is influenced by the diameter of the
smaller grains of sand to filter out microorganisms. Biological nitrification
and denitrification process processes occur in the BSF (Murphy
et al., 2010). Above the surface layer of sand medium filters are
designed to biosand filter±5 cm height of water stored at all times.
Shallow water layer provides sufficient oxygen to the biofilm layer that exists
to keep alive and develop and maintain the biolayer (schmutzdecke) so as not
to interfere with the speed of water coming. Schmutzdecke is a German word which
means 'dirty layer'. This sticky film, which is brownish red in color, composed
of organic material decomposed, iron, manganese and silica and therefore acts
as a good filter that acts to remove colloidal particles in raw water. Schmutzdecke
zone is also a basis for biological activities, among others, such as Pseudomonas
bacteria, flavobacterium and alcaligenes. After five days, the composition of
bacteria in the biolayer will consist of a collection of diverse bacteria, the
types of dominant filament. After more than a week, it will be a little overgrown
with fungi such as Fusarium, Geotrichum and Sporotrichum
will appear and cause the reduction of BOD content and can degrade some soluble
organic material in raw water, which is useful for reducing taste, odor and
warn (Droste, 1997). Generally, the ideal time was required
so that biosand filter can be used for a maximum of 3 months. Therefore with
increasing time of usage, the layers will be thicker which requires higher efficiency
and effectiveness of the cleaning process during this period (CAWST,
Several studies have been reported on the performance of the BSFs in reducing
bacteria, virus, iron and turbidity from feed water (Ahammed
and Davra, 2011; Duke et al., 2006; Earwaker,
2006; Jenkins et al., 2011; Elliott
et al., 2006, 2008, 2011;
Stauber et al., 2006). With the advantages of
the biosand filter it can solve problems that arise from the water wells in
a swampy area with high concentration of organic substances, turbidity, iron
and manganese etc.
Organic substances need to be removed before the water is disinfected with
chlorine, as it reacts with chlorine and produces trihalomethanes, which have
recently been found to be carcinogenic and a high turbidity will result in disruption
of osmoregulation system, such as breathing the aquatic organisms and can inhibit
the penetration of light into the water. The high turbidity values can also
complicate efforts to reduce the effectiveness of filtration and disinfection
in water purification processes, whereas iron and manganese make the water turns
brownish and blackish which can also cause a bad odor (Metcalf
and Eddy, 2003).
The objective of this study was to investigate the efficiency and effectiveness of biosand filter (BSF) design in removing organic substances (KMnO4) and turbidity in drinking water supply.
MATERIALS AND METHODS
Biosand filter design: Biosand reactor unit is a rectangular filter
unit made from 8 mm glass with dimensions 30x30x100 cm. The use of the glass
is in the formation of biofilm layer and for visual observation the filtration
process. Each unit has the same height with the filter medium. Total height
of the medium from each biosand filter Reactor is 70 and 5 cm above the water
level of fine sand. Water prevents the sand from drying also keeps the moisture
in the fine sand during the formation of a biofilm layer and prevent the layer
of biofilm from damage. Then from 5 cm from the surface of the water, a diffuser
plate made from fiber plastic is used. The function of diffuser plate is to
maintain the flow rate of water into the BSF reactor unit. The medium used in
BSF reactor as sand local and gravel. The water is received through the orifice
hole that is placed on the lateral pipe. Locally obtainable river sand was selectively
sieved, using a set of sieves for sand analysis and the portion passing through
0.25 mm sieve and retained on 0.150 mm was used in the present study as filter
medium. The filter medium had an effective size of 0.23-0.25 mm filled into
the reactor with a depth 40 cm on the top and coarse sand (0.60 mm size) and
15 cm in the middle of media. Lastly, in the bottom layers of underdrain have
gravel (10-12 mm size) of 15 cm. The sand and gravel was washed several times
using tap water until the wash water became clear, the purpose of this washing
is to eliminate the pollutants in the filtration media and dried in the oven
for 24 h until at temperature of 105°C for a sterilizer, after that the
media were put into the reactor sequentially. The filter media were sieved and
washed to remove the clay particles, organic contents and other materials according
to the standard procedures for BSF developed by CAWST (2008).
Schematic diagram of the filter is presented in Fig. 1.
Water sources: The water value was observed to suggest the characteristic
of ground water in developing countries. The water source from wells (ground
water) located in swampy areas tend to contain organic substances and high turbidity.
Wells located in Samarinda, Indonesia.
|| Schematic biosand filter design
The well water is used for daily activities such as washing clothes, bathing
and for drinking water. Experiment for the duration (7 days) after ripening
for 20 days after that well water was collected in 4 samples each BSF every
day and 1 sample at the inlet. Experiments conducted from October to November
2010 during the rainy season affected the quality of well water. The characteristics
of the well water pre-filtration are shown in Table 1.
Filter operation: The experiments were performed by using 4 units of
BSF reactor; four units used well water (ground water) as influent were conducted
simultaneously. Each filter was fed a standard batch of 20 L of the influent
water mixture per day for 20 days, except during weekly testing. Each valve
on the tank was opened and set appropriate discharge that have been planned
(BSF 1 and 2 used a flow rate of 0.2 m h-1 with a discharge 5x10-3
L sec¯1 while BSF 3 and 4 used the flow rate of 0.4 m h-1
with a discharge 1x10-2 L sec-1) was then flowed into
each reactor. Ripening during 20 day used a continuous system for 24 h, ripening
period was 1-3 weeks to growth biofilm layer, this period was allows efficient
growth of the biological layer in the sand (Ngai and Walewijk,
2003). After 20 day ripening Schmutzdecke at fine sand layer the processing
was no longer using a continuous system, BSF 1 and 3 with periods of pause 6
h and BSF 2 and 4, the pause period that was used is for 12 h, while for the
flow it was from morning until the evening. Official testing begin in week 4,
allowing an initial 20 days ripening period for the biological zone to be created
inside the sand with bubble aerator for the supply O2 for feeding
the biological zone and after that sampling measurements were taken. Samples
were taken at the point of inlet and outlet of each BSF reactor samples every
day during seven days. The filters were charged once a day with raw water prepared
|| Characteristic of water pre-filtration
|*Kalium permanganate, **Nephelometric turbidity unit
|| Characteristic and decrease of organic substances concentration
(KMnO4) inlet and outlet using biosand filter treatment
|*Kalium permanganate, BSF: Biosand filter
|| Characteristic and decrease of organic substances concentration
(KMnO4) inlet and outlet using biosand filter treatment
|NTU: Nephelometric turbidity unit, BSF: Biosand filter
The schedule of the filter operation is presented in Tables 2
and 3. The test was conducted at room temperature and the
water temperature was set at 25-34°C.
Sample and analytical method: Samples were collected at different intervals
for analysis, influent water and grab samples. Grab samples were analyzed by
APHA standard method for parameter such as organic substance concentration (KMnO4)
and turbidity of the filtered water where 1.5 L bottles were used to collect
water samples from each reactor. The pre and post-filtration water sampling
organic substances (KMnO4), preservation and tests were performed
according to the APHA standard methods (APHA, 1992). The
turbidity of water was analyzed by a turbidity meter. pH of pre and post-filtration
water was recorded by a pH meter.
The statistical analysis of the data was performed using t-test for efficiency of organic substances concentration (KMnO4) and turbidity.
RESULTS AND DISCUSSION
Decrease of organic substances (KMnO4): From this study the average efficiency was determined. From Table 2 it can be seen that the efficiency achieved by the four units of BSF reactors with flow rate variations and pause, did not show any a significant difference. The average efficiency of organic substances (KMnO4) decreased from BSF 1 was 76.82%, 74.17% reduction for BSF 2, 71.28% for BSF 3 and 73.29% for BSF 4. This comparison showed the differences in the efficiency of each BSF, where BSF 1 better than with BSF 2, 3 and BSF 4.
Interaction contact time with period of paused and flow rate had great impact
for decrease organic substances (KMnO4) average each unit biosand
Filter reactor can decrease organic substances (KMnO4) even in period
of paused 6 and 12 h, flow rate of 0.2 and 0.4 m h-1, Biofilm on
surface of fine sand had interaction with organic substances influent from well
water transform organic substances became energy for growth of biofilm and reduce
organic substance. Then, period of paused and aeration for supply O2
5 cm on the surface of fine sand layer in water was improvement the growth biofilm
and decrease of organic substances (KMnO4). Figure
2a-d shows the removal of organic substances (KMnO4)
for all four BSF reactors, where a high removal of the organic substances was
recorded in treatment period of 21-27 days after ripening and removal of the
organic substances was found in all the BSF reactor and Fig. 2
shows all removal of organic substances (KMnO4) from the range of
21.22 mg L-1 until 4.22 mg L-1. In water and waste water
treatment, BSF showed that the presence of well-developed biofilms and associated
microorganism was required for effective nutrient cycling and biodegradation
of organic compounds, under both aerobic and anaerobic conditions (Mendoza-Espinosa
and Stephenson, 1999). The high concentration of organic substances (KMnO4)
of the water contained in the groundwater may indicate or provide information
on the location of the wells, because for those near septic tanks and swampy
area, organic substance can easily infiltrate into the wells. Pollution of organic
substance and turbidity in well water comes from poor sanitation in the form
of household and industrial waste.
Organic compounds are compounds composed of atoms of C, H, O, N, S, P and X with the carbon atom as its backbone and the other atoms will bond with the carbon atoms by covalent bonds. There are so many kinds of organic compounds ranging from a short carbon chain (such as trihalomethane, methanol) to long chains (carbohydrates, humid acid and so on). Many types of organic compounds depend on the pollutant source.
Measurement numbers of permanganate (KMnO4) are a measurement of organic substances in water, where organic substances in water are oxidized by strong oxidizing KMnO4 at boiling temperature (±100°C) for 10 min. The more organic matter in the water, the more of oxidant KMnO4 is needed to oxidize organic compounds. The measurement of organic matter in the aggregate (general) is to determine the concentration of organic substances in water in general, without knowing the type of compounds. Basic measurements of the aggregate are based on the nature or characteristics of organic compounds in general.
The removal of organic substances in BSF reactor that takes place is a biochemical
process. The pollutants are degraded in the waste by organisms that accumulate
in the lining fine sand called Schmutzdecke or biofilm. Biochemical processes
occurred due to decomposition of microorganisms/ aerobic bacteria that used
oxygen to break down pollutants (Metcalf and Eddy, 2003)
in the reaction shown below:
new microbes H2O+CO2+NH
||Decrease in organic substances (KMnO4) and turbidity
using biosand, (a) Filter 1, (b) Filter 2, (c) Filter 3 and (d) Filter 4
According to Metcalf and Eddy (2003) the growth of microorganisms
and the reduced concentration of organic substances, indicates that the microorganisms/microbes
are capable of degrading and utilizing the concentration of organic substances
as carbon sources, energy or sulfur for growth. This study an important and
significant positive effect of decrease organic substance using biosand filter
with connection flow rate and period of pause has been identifying. Although,
biofilm on surface fine layer had not measured in this research because is very
Decrease of turbidity: Table 3 shows the average efficiency
as determined by the removal of turbidity. From Table 3 it
can be seen that the efficiency achieved by the four units of biosand filter
with flow rate variations and pause, which differed did not showed a significant
difference. Average efficiency of turbidity decrease in BSF 1 was 96.56 and
94.08% in BSF 2, 96.52% in BSF 3 and 96.03% in BSF 4. From this comparison despite
having the same average efficiency, the two variations can reduce the turbidity
with an efficiency that was quite large and effective. It the reduction reached
>50% indicate that the biosand filter reactor can remove turbidity in the
well water with a fairly effective variation occurring in BSF 1.
Extensive moment contact are reflected in batch organize process make decrease
and effluent quality of water. Varying form period of paused (6 and 12 h) and
flow rate BSF 1 and 2 used a flow rate of 0.2 m h-1 with a discharge
5x10-3 L sec-1 while BSF 3 and 4 used the flow rate of
0.4 m h-1 with a discharge 1x10-2 L sec-1)
operation improved decrease turbidity. The utilize of fine and coarse sand comparison
the filter medium had an effective size of 0.23-0.25 mm filled into the reactor
with a depth 40 cm on the top and coarse sand (0.60 mm size) and 15 cm in the
middle of media improvement significant in effluent turbidity. Figure
2a-d shows turbidity removal with ranges from 28-30 NTU
of the well (ground) water, during the 7 days of experiment after ripening for
20 day for all BSF reactors. From this result the removal ranges from 2 to 1
NTU. The reduction of turbidity is a physical process (physical, sedimentation
and adsorption) which generally are a very effective method for reducing levels
of turbidity that cannot be removed (Gerba et al.,
1988). Decrease in turbidity in the BSF reactor was influenced by the layer
of sand. In each unit of reactor there were layer of fine and coarse sand serving
as a layer of biofilm growth as well as a buffer layer and also functions in
removing suspended materials, organic and inorganic from well water (ground
water), that caused turbidity after the passing sand layer decreased quite signi
icantly. Numerous studies shown the relationship between turbidity reduction
and microbial contamination of raw water and treatment (LeChevallier
et al., 1991; Clark et al., 1992;
LeChevallier and Norton, 1993) and a few documented waterborne
illness epidemics were related by high turbidity levels (Schwartz
et al., 2000). The experimental positive result for turbidity decrease
by biosand filter was had good performance for used in developing countries
where this technology is needed the most, since a lot of BSF-target households
tend to be more urban and rural area depend on water sources especially ground
or well water sources that may experience elevated levels of cyclic or year
pH values: The seeding process was carried out to form a layer, the
layer of the biofilm (biological zone) to be formed on top of filter medium
(fine sand) that are expected to degrade the organic substances concentration
and turbidity to be used as intended. In this process many factors that must
be considered such as temperature, pH and nutrients so that the microorganisms
can produce an optimal biofilm layer. In the seeding process the addition of
oxygen (O2) supply is to help accelerate the formation of a biofilm
layer. Biofilm growth is heavily influenced by environmental factors such as
the interaction between bacteria, plastered surfaces, surface moisture, food
available, ionic bonds, Van der Waals bonding, surface tension and condition
(Yung, 2003). In addition, the supply of oxygen, pH and
temperature and contact time must also be considered. This seeding process used
aerobic microorganisms, their need a supply oxygen for growing and then we addition
bubble aerator for the oxygen supply of raw water. pH was also monitored in
order to maintain in neutral state, because the microorganisms especially bacteria
can grow well in this environment at pH range of 5-7 during the seeding process
that shows the growth of microorganisms on the filter media. Temperature between
25 to 28°C was good for microorganism because microorganisms can grow well
at these temperatures (mesotherm temperatures). This study was measured pH and
no significant result small negative for relationship between flow rate and
period of paused. Characteristics of pH in the well water during study period
are presented in Table 2 and Table 3.
Based on the results of research and discussion, it can be drawn some conclusions based on research objectives are the results obtained in laboratory testing that the concentration of organic substances (KMnO4) and turbidity with the average value of the overall efficiency more than 50% this proves that with biosand filter can be promising tool and variations flow rate 0.2 m h-1 and a pause period 6 h at biosand Filter reactor 1 shows the efficiency decreased concentrations of organic substances (KMnO4) and turbidity in well water most effective when compared to the another variation of flow rate and paused period. This study was conducted The BSF design, construction, operational and maintained as technology become solution in urban and rural area to provide safe water and drinking water in developing countries.
This research was carried out with the support and special thanks for Laboratory of Faculty of Forestry, Faculty of Agriculture and Faculty of Engineering, University of Mulawarman, Indonesia.
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