• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.40 no.1
• /
• pp.41-46
• /
• 2008

In this study, dewaterability, one of the important properties of wastewater sludge, was investigated using a simple capillary suction time (CST) measurement method. It turned out that one could use the results of CST to find optimum flocculants ratio to improve drainage in wastewater treatment for the printing paper, tissue paper, and newsprint paper mill. Since the optimum ratio of flocculants could be determined with the value of CST, COD removal efficiency could be improved and optimum floc strength could be achieved with precise ratio of flocculants. It was thus that using CST for determining the optimum ratio of flocculants could be economical by reducing the amount of flocculants. Dewaterability could be measured within several seconds using the values of CST in a precise way. The dewaterability could also be useful in investigating the optimum ratio of flocculants.

• Journal of Forest and Environmental Science
• /
• v.30 no.1
• /
• pp.85-90
• /
• 2014

Dewaterability, one of the important properties of wastewater sludge, was investigated using a simple capillary suction time (CST) measurement method. CST and SRF have a very close co-relation. It was convinced that CST method was quite effective, and compensating the time-consuming SRF of conventional drainage measuring method. It turned out that one could use the results of CST to find optimum flocculants ratio to improve drainage in wastewater treatment for the tissue paper production at a mill. Since the optimum ratio of flocculants could be determined with the value of CST and COD removal efficiency could be improved with precise ratio of flocculants. Thus, using CST for determining the optimum ratio of flocculants could be economical by reducing the amount of flocculants. Dewaterability might be measured within several seconds using the values of CST in a precise way. The dewaterability could also be useful in investigating the optimum ratio of flocculants.

• Journal of Korean Society on Water Environment
• /
• v.31 no.6
• /
• pp.625-631
• /
• 2015

In this study, low cost bio-flocculants, chitosan, cationic starch and Mg-sericite, were used as a flocculant to harvest freshwater microalgae, Chlorella vulgaris. Chitosan, cationic starch and Mg-sericite separated successfully >98% of C. vulgaris at following optimal parameters: 90 mg/L chitosan at pH 6-7, 70 mg/L cationic starch at pH 9-10 and 50 mg/L Mg-sericite at pH 4-5. A relatively high correlation coefficient (R²) of 0.9993 for chitosan, 0.9971 for catonic starch and 0.9924 for Mg-sericite was obtained. The investigated flocculants amount increased linearly with increasing the microalgae amount. The biopolymer, Mg-sericite, was more effective than that of other investigated flocculants. These results indicated that a bio-flocculants, chitosan, cationic starch and Mg-sericite, could prove to be an effective flocculant for economical production of microalgae biomass. In addition, Mg-sericite was more effective comparing to the other investigated flocculants.

• KSBB Journal
• /
• v.26 no.2
• /
• pp.143-150
• /
• 2011

The aim of the study was to optimize harvesting method for concentrating microalgae from microalgae mass culture. It is well known that the mass density of microalgae is usually very low and these are small size (5-20 ${\mu}m$) in the culture medium. It is essential that microalgae is harvested and concentrated economically for economical biodiesel production from microalgae. In this study, to determine optimized conditions for microalgae harvesting by chemical flocculation. Flocculation of three algae, Chlorella ellipsoidea, Dunaliella bardawil, and Dunaliella tertiolecta, was performed using various chemical flocculants, such as inorganic flocculants (aluminium sulfate, aluminium potassium sulfate, ferrous sulfate, ferric sulfate, ferric chloride, calcium hydroxide, sodium carbonate, sodium nitrite, and sodium aluminate), organic flocculant (polyacrylamide), and biopolymer flocculants (chitosan and starch). The results indicated that aluminium based inorganic flocculants is suitable for microalgae harvesting such as Chlorella ellipsoidea, Dunaliella bardawil, and Dunaliella tertiolecta. The results also recommended that flocculant doses, agitation speed, agitation time, sedimentation time for economical microalgae harvesting method using chemical flocculants.

• Environmental Engineering Research
• /
• v.11 no.5
• /
• pp.266-276
• /
• 2006

Commonly, the flocculant is dissolved in process or recycle water in industrial plant which has many ionic materials. Therefore, the polymer degradation in aqueous solution by chemical, mechanical or bacteriological may occur, sometimes rapidly. Even if the same flocculant is dissolved, the flocculation characteristics and the properties of dissolving polymer varied with the kind of dissolving water. In this study, we try to estimate the interaction between flocculants and ionic materials in dissolving water using self inversing emulsion polymer; polyacrylamide-co-trimethyl ammonium ethyl acrylate chloride flocculants which have varying molecular weights and structures at a several conditions. The polymeric flocculant is dissolved in artificial dissolving water with Potassium Chloride (PC), Calcium Chloride anhydrous (CC), Potassium Hydroxide (PH), Sodium Chloride (SC), Sodium Bromate (SB) and Iron (II) Sulfate Heptahydrate (IS) as ionic sources. Experimental results indicate that the cationic and anionic ions in dissolving water induce the hydrolysis, degradation of cationic functional group and uncoiling of polymeric flocculants, therefore, the flocculation efficiency decreased by undesired polymer. According that result, it is important to estimate not only its structures and physical properties but also the qualities of dissolving water to optimize the efficiency.

• Journal of Forest and Environmental Science
• /
• v.23 no.2
• /
• pp.119-122
• /
• 2007

Actually, about 45% of total costs for wastewater treatment in a papermaking mill is spent for sludge disposal and the cost of chemicals used to improve the dewaterability of sludge takes much part of it. In order to reduce sludge disposal cost and to improve the efficiency of sludge treatment, it is necessary to minimize the amount of water contained within the sludge and hence to improve the dewaterability of the sludge. The objective of this study was to elucidate the way of improving the dewaterability of sludge. Three types of wastewater from a tissue paper mill, a printing paper mill and a newsprint mill were used and two types of high molecular weight flocculants (anionic PAM and cationic PAM) were used to treat the wastewater. Dewaterability of sludge was evaluated by measuring floc strength.

• Environmental Engineering Research
• /
• v.12 no.1
• /
• pp.21-29
• /
• 2007

For this study, we polymerized polyacrylamide base flocculants (PAA) and tested their properties and settling efficiency as a treatment for potable water. The most common chemicals for potable water treatment in Korea are alum or PAC. However, due to various reasons (such as rainy season or algae), inorganic flocculants cannot be solely depended on to solve all the problems caused by the poor quality of inflow water. When PAA coupled with coagulants in a potable water purification process is used, the turbidity removal efficiency increases by a factor of three on a single chemical system using PAC (Raw water: 5.21 NTU; Treated PAA+PAC: 0.34 NTU; and, Treated PAC: 1.04 NTU). It is possible to offset the toxic effect of residual monomers in treated water using PAA, because the concentrations of residual acrylamide are less than 400 mg/L in the polymer itself and less than $0.04\;{\mu}g/L$ in the treated water base at a dosage of 0.1 mg/L. Therefore, PAAs may be a workable, and dependable, potable water treatment process for the high pollutant level of resource water.

• Geomechanics and Engineering
• /
• v.13 no.2
• /
• pp.319-331
• /
• 2017

This vacuum preloading combined with polyacrylamide (PAM) flocculation was proposed to separating solid-liquid in waste slurry and to improving bearing capacity of soft soil ground. By using waste slurry taken from drilled shaft construction site in Shanghai, China, a series of settling column tests with four typical flocculants and one normal for waste slurry were carried out for comparative analysis. The optimal amounts for each flocculant were obtained from the column tests. Then, model tests on vacuum preloading with anionic polyacrylamide (APAM) flocculation and without flocculants were carried out. The out of water and the settlement of slurry surface ground were monitored during the model tests, and the changes in water content, particle-size and pore-size distributions in different positions after the model tests were measured and discussed. It is found that water content of the waste slurry without APAM flocculation changed from 204 to 195% by 24 hours standing and 15 hours vacuum preloading, while the water content of the waste slurry with APAM flocculation was declined from 163 to 96% by 24 hours standing, and was further reduced into 37% by 136 hours vacuum preloading, which shows that the combined method is feasible and effective.

• Environmental Engineering Research
• /
• v.22 no.3
• /
• pp.255-265
• /
• 2017

Polyelectrolytes are commonly used as flocculants in drinking water treatment. However the growing concerns about their toxicity have motivated the search for biocompatible flocculants. Here, we show that gelatin, a natural amphoteric polyelectrolyte, can be effectively adsorbed on clay surfaces and can potentially be a suitable substitute for existing flocculants. The adsorption of gelatin from its aqueous solution onto the mineral clay surfaces at different conditions was systematically investigated using the design of experiments methodology. The gelatin adsorption was found to vary considerately with pH variation showed a maximum adsorption at its isoelectric point. The amount of adsorbed gelation increased with increasing pH from 3 to 5, attained a maximum at pH 5 and then decreased with increasing pH from 5 to 11. Similarly, the amount of adsorbed gelatin showed decreasing trends around salt concentration of 0.05 M and temperature $35^{\circ}C$. On the other hand, the adsorption was continuously increased with time and polymer concentration in the range of 0.1-0.9 mg/dL. Finally, the jar tests confirmed the ability of gelatin for using a natural flocculant for water treatment.

• KSBB Journal
• /
• v.26 no.5
• /
• pp.443-452
• /
• 2011

In this study, inorganic flocculant with biodegradable polymer flocculant was usedfor microalgae harvest. The aim of this study was to optimize the concentration of inorganic flocculant, the concentration of biodegradable polymer flocculant and reaction volume for decreasing the amounts of flocculant and obtaining the suitable pH range for seawater by response surface methodology. The flocculation of three marine microalgae, Chlorella ellipsoidea, Dunaliella bardawil, and Dunaliella tertiolecta, using inorganic flocculants and biodegradable polymer flocculants was investigated. The results indicated that the optimal flocculant quantity showed 0.1 g/L of ferric chloride, 7.5 g/L of chitosan on Chlorella ellipsoidea. In the case of Dunaliella bardawil, the optimal flocculant quantity showed amount of ferric sulfate more than 0.12 g/L and chitosan more than 0.75 g/L. In the case of Dunaliella tertiolecta, the optimal flocculant quantity showed 1.0 g/L of sodium aluminate, 0.75 g/L of chitosan.