International Journal of Eco-Innovation in Science and Engineering Vol 3 .
, 2022 .
https://ijeise.
id/ E-ISSN: 2721-8775 Article The Effect of Velocity Gradient and Camp Number on Solids Removal using Bio-Coagulant from Corbula faba Hinds Shells Ardika Nurmawati1,a.
Kindriari Nurma Wahyusi1,b*.
Retno Dewati1, and Jauhar Hilmy1 1 Department of Chemical Engineering.
Faculty of Engineering.
Universitas Pembangunan Nasional (UPN) AuVeteranAy Jawa Timur.
Gunung Anyar 60294 Surabaya.
Indonesia *Corresponding author: .
indrinurma@gmail.
|Phone number: - Received: 17th March 2022.
Revised: 27th August 2022.
Accepted: 24th October 2022.
Available online: 22 November 2022.
Published regularly: May and November.
Abstract The TSS and TDS values of water are required to meet the standard.
Like coagulation, the pretreatment process in water helps reduce solid content in water.
The coagulant destabilizes water pollutants and helps flocs formation with the coagulation process.
This paper studies the performance of chitosan biocoagulant produced from Corbula faba Hinds shells.
The velocity gradient and the Camp number of solids removal were also evaluated.
The velocity and period of rapid mixing varied from 110 to 150 rpm, and the velocity gradient (G) was 181.
2 to 288.
5 s-1.
The mixing period also ranged from 1 to 5 minutes.
The highest TSS and TDS removal resulted in 140 rpm or 260.
2 s-1 and 4 minutes of mixing.
The residual TSS and TDS decreased with the increase of Camp Number until reaching a point and increased again Keywords: Camp Number.
Chitosan.
Coagulation.
Solids.
Velocity gradient Introduction Water is crucial for every organism, with a quality standard in every use.
One parameter that needs to be controlled is solids concentration, such as Total Suspended Solids (TSS) and Total Dissolved Solids (TDS).
TSS contained solids with a size of more than 2 AAm like clay minerals, plankton, and humic substance.
In contrast.
TDS particle size is less than 2 AAm or ranges from 0.
to 1 AAm, like inorganic salts (Na .
Mg2 .
Ca2 .
SO42-, etc.
) and dissolved organic matter .
high concentration of TSS and TDS in the water results in decreased water quality.
Their presence becomes contaminants and toxic sources affecting aquatic organisms, water colour, and taste .
Jagir River, located in Surabaya.
East Java.
Indonesia, is one of the raw water sources for tap The water quality of the Jagir River decreased due to various activities around the river, whether domestic or industrial.
The water monitoring result from 2010 to 2013 showed that the water from PDAM Jagir intake condition did not meet tap water standard.
The average BOD concentration was 5,715 mg/L, the COD was 86 mg/L, the TSS was 59.
59 mg/L, and the pH 05 .
According to Indonesian government regulation number 82:2001, the standard for water is divided into four classes.
Several water standards for domestic and agricultural uses .
lass I and II) are TSS 1,000 mg/L.
TSS 50 mg/L.
BOD 2-3 mg/L, and COD 10-25 mg/L.
Under those conditions, the water needs pretreatment to remove pollutants before use .
The coagulation process is part of the water pretreatment process.
This process runs with the help of a coagulant and gets rid of solids and colloidal form components.
The coagulation process mechanism may leaded by zeta potential DOI:10.
4186/ijeise.
id/E-ISSN: 2721-8775 International Journal of Eco-Innovation in Science and Engineering Vol 3 .
, 2022 double-layer The addition of coagulant caused unstable conditions affected by the Van der Waals force and Brownian movement of particles .
There are many types of commercial coagulants used in water treatment.
Chitosan, as a bio-coagulant, became an alternative to metal coagulant uses like aluminum and iron.
The advantages use of chitosan were non-hazardous material, non-corrosive, and biodegradable.
The sludge production was also easy to handle and safe for the environment .
It not only works as a coagulant, but chitosan also act as a flocculant due to its high molecular weight, cationic charge density, and bridging the flocks and precipitation with their stability in any pH range condition .
Chitosan is a derivative product of chitin that can be found easily in the exoskeleton of crustaceans .
rab, shrimp, praw.
, mollusks .
nail, oyste.
, fungi, and yeast .
Corbula faba Hinds, or white mussel, is a bivalve mollusk found easily in muddy or shallow water near the beach.
Sidoarjo.
East Java.
Indonesia, white mussel production is up to 8.
6 million kg annually .
This high mussel production also generates a high quantity of shell waste.
Mussel shell compositions 62% mineral content and 21.
With the potential content of chitin, mussel shells likely be processed to become According to previous research, chitosan from these shells had a 65.
08% on deacetylation degree .
The coagulation process took several steps.
First is rapid or flash mixing, when the coagulant is added to sample water and stirred at high speed.
Then the rate is reduced .
low mixin.
to allow particles to form larger flocs that be easier to settle And the last step, the sediment developed and separated from the water .
In the coagulation process, many factors affected the performance of solids removal.
The water characteristics, coagulant used, and operation conditions influenced the result.
Camp .
evaluated the degree of mixing measured by velocity gradient (G) related to the shear force in the water.
Another property that plays a role in the coagulation is Gt or Camp Number.
This value showed the sum of particle collisions that equal velocity gradient and detention time .
This study investigated the correlation of velocity gradient and Camp number in the coagulation process of river water using chitosan from Corbula faba Hinds shells.
Those two parameters correlated with the solids removal of the sample water, shown by TSS and TDS values.
Material and Method 1 Material In this experiment, the water sample was from the Jagir River.
The sampling port was in the sluice gates area during the rainy season.
The biocoagulant proceeds from white mussel shells The shells were collected from Kenjeran beach, located at Sidoarjo.
East Java, and processed to make chitosan.
2 Method 1 Bio-coagulant Production Chitosan production was obtained in several First, the collected white mussel shells were cleaned and dried under sunlight, followed by the The dried shells were grounded and sieved with size 100 mesh to obtain a uniform powder.
The powder shells were demineralized using chloric acid.
After removing the mineral, the shell reacted with 3.
5% NaOH solution to extract the To transform the chitin become chitosan, it reacted again with 60% of the NaOH solution under certain conditions.
The detailed process was described in the previous work .
2 Coagulation Test The coagulation was done using jar-test equipment that contains six beaker glasses for water testing with a volume of 1000 mL.
Chitosan, as a coagulant, was dissolved in 100 mL of 1% acetic acid solution.
The solution was stirred for 6 hours to ensure the chitosan dissolved.
The chitosan solution was added to the sample water until the water pH was neutral.
The mixture was stirred using two-speed levels, rapid and slow The rapid mixing varied from 110 to 150 rpm, with the period also differing for 1 to 5 The slow mixing was done after the rapid mixing at 40 rpm for 10 minutes.
The precipitation process was done for 1 hour to allow the flocs to settle down.
After that, the mixture was filtered to separate the sediments.
The coagulant performance was evaluated by the decrease of the TSS and TDS that showed the solids removal.
DOI:10.
4186/ijeise.
id/E-ISSN: 2721-8775 International Journal of Eco-Innovation in Science and Engineering Vol 3 .
, 2022 The velocity gradient is one of the essential factors in the coagulation and flocculation It measured the degree of mixing based on the power inserted into the water .
The value of the velocity gradient is depended on the power entered into the water, the water viscosity, and the flocculator capacity .
The velocity gradient can be calculated using Eq.
ya = OoycEAEyuNycO where G is velocity gradient .
P is power imparted to the water .
att or N.
AA is absolute viscosity of the water (N.
s/m.
, and V is basin volume .
The power applied in the basin is related to the water flow types, turbulent or laminar, where the Reynold Number can be calculated as shown in Eq.
ya 2 ycuyuU ycAycIyce = yca AEyuN where Da is the diameter of the impeller, n is rotational speed .
, and A is water density .
g/m.
The value of Reynold Number indicated the flow of the water, whether laminar .
ess than .
or turbulent .
ore than .
The power was calculated using Eq.
3 for laminar flow and Eq.
for turbulent flow .
ycE = ycoya ycu2 ya 3 yuN ycE = ycoycN ycu3ya 5 yuU where kL is impeller constant for laminar flow and kT is impeller constant for turbulent flow.
Multiplication between the detention time and the velocity gradient will result in Camp Number (G.
The value of Gt was more critical than the separated value of G and t.
This parameter can be calculated using Eq.
yayc = ycOoycEAEyuNycO = 1AEycE OoycEycOAEyuN where t is rapid mixing period .
and Q is flowrate .
velocity gradient up to the minimum condition.
Then the TSS residue increased again with a higher velocity gradient applied (Fig.
The lowest residual TSS resulted in 260.
2 s-1.
The velocity gradient was related to the shear force applied in the sample water.
The increased power shaft increased the velocity gradient and impacted the shear force.
A higher velocity gradient maximized the flocs formation process, but when the velocity gradient exceeded its limit, it broke the floc and reduced its size .
The same condition also appears in TDS analysis (Fig.
The minimum TDS residue was reached when 260.
2 s-1 of velocity gradient was applied.
Residual TSS .
g/L) 3 Velocity gradient and Camp Number Calculation G .
Poly.
Poly.
Poly.
Poly.
Poly.
Fig.
The effect of velocity gradient in coagulation process to residual TSS Another factor that affected the floc formation in the coagulation and flocculation process was detention time.
Fig.
1 and Fig.
2 show that the lowest residual TSS and TDS resulted in 4 minutes of rapid mixing.
These conditions appeared due to the interaction between ions from the chitosan and water pollutants.
A higher period of mixing gave the contact time to the particles.
But on the contrary, it also affected the stability of the flocs if the mixing time took longer.
It caused flocs breakage and size reduction .
Results and Discussion In this experiment, the velocity gradient value differed based on the rapid mixing speed.
Based on the coagulation results, the residual of TSS in the water sample decreased with the increase of DOI:10.
4186/ijeise.
id/E-ISSN: 2721-8775 Residual TDS .
g/L) Residual TDS .
g/L) International Journal of Eco-Innovation in Science and Engineering Vol 3 .
, 2022 G .
Poly.
Poly.
Poly.
Poly.
Poly.
Fig.
The effect of velocity gradient in coagulation process to residual TDS Residual TSS .
g/L) 1 t = 4 min GEf Fig.
The effect of Camp number to residual TSS in 4 minutes mixing The effect of Camp Number on residual TSS and TDS showed in Fig.
3 and Fig.
4 at 4 minutes of rapid mixing time.
The residual TSS and TDS decreased until the minimum Camp Number value at 62,443.
46 and afterward increased again with the increase of Camp Number.
With those Camp Number values, the final TSS and TDS values in the water sample were 3 mg/L and 286 mg/L, respectively.
t = 4 min GEf Fig.
The effect of Camp number to residual TDS in 4 minutes mixing Conclusions In the coagulation process, the velocity gradient and the Camp number affected the solids removal in the water.
With the act of chitosan from Corbula faba Hinds shells as bio-coagulant, the floc formation was more convenient.
A higher velocity gradient up to 260.
2 s-1 removed more TSS and TDS.
The velocity gradient limitation due to the water shear rate broke the formed flocs.
The same condition also appeared in the Camp number evaluation.
The maximum rapid mixing time applied in the mixtures was 4 minutes.
More than that limitation, the residual TSS and TDS were higher.
References