• Environmental Engineering Research
• /
• 제20권2호
• /
• pp.199-204
• /
• 2015

In this study, a novel phosphorus removal filter made of brass scrubber with higher porosity of over 96% was fabricated and evaluated. The brass scrubber was surface-modified to form copper hydroxide on the surface of the brass, which could be a phosphate removal filter for advanced wastewater treatment because the phosphates could be removed by the ion exchange with hydroxyl ions of copper hydroxide. The evaluation of phosphate removal was performed under the conditions of the batch type in wastewater and continuous type through filters. Filter recycling was also evaluated with retreatment of the surface modification process. The phosphate was rapidly removed within a very shorter contact time by the surface-modified brass scrubber filter, and the phosphate mass of 1.57 mg was removed per gram of the filter. The possibility of this surface-modified brass scrubber filter for phosphorus removal was shown without undesirable sludge production of existing chemical phosphorus removal techniques, and we feel that it would be very meaningful as a new wastewater treatment.

• 미생물학회지
• /
• 제29권2호
• /
• pp.117-122
• /
• 1991

In order to improve the removal ability of phosphate, Spheroplast fusions were performed among auxotrophic mutants of Aeromonas hydrophila isolated from waste water, named A13 and A14, Aci37 auxotrophic mutant of Acinetobactercalcoaceticus, and auxotrophic E. coli HR262/pCE27 carring pit gene. Eight fusants obtained from this experiment showed different biochemical characteristics. When the rate of phosphate uptake among fusants (F1-F8) was investigated in Phosphate Uptake Medium (PUM), F8 strain showed the highest rate for phosphate removal, 7 times as much as control after two hours incubation. The role of cations ($Mg^{++}$ ,$Ca^{++}$ , $K^{+}$ in phosphate uptade by F8 was also investigated in PUM without each salt. $K^{+}$ seemed to be crucial. Being compared with phosphate untake rate in PUM, that in PUM without $K^{+}$ was reduced 1.5 times. Therefore, by applying F8 strain and $K^{+}$ in practical environmental system, the increased efficiency in phosphate removal can be derived.

• 상하수도학회지
• /
• 제27권6호
• /
• pp.751-759
• /
• 2013

This study is carried out to get the basic design parameters for phospate removal facilites from wastewater by Tobermolite. The phosphate removal by the apatite formation on the surface was affected by several important factors, temperature, ions present in wastewater stream, contact time, recirculation rate, and etc. In case of the temperature, with the increase of temperature, the apatite formation was accelerated. When temperature increased from $15^{\circ}C$ to $35^{\circ}C$, removal efficiency of phosphate increased from 83 % to 93 %. An increase of calcium and fluoride ion content increase the apatite formation, however, bicarbonate and magnesium ion inhibited the crystallization of apatite. As expected, when the recirculation rate was increased from 1 Q to 3 Q, at EBCT (Empty Bed Contact Time) 60min enhanced removal efficiency was observed. The more the recirculation rate increased, the more the removal efficiency increased. According to the results of column experiment using an actual wastewater with low and high phosphate concentration (5 mg/L and 50 mg/L-P), the removal efficiency was 77 % at EBCT of 45 min, and 80 % at 60 min. It was suggested that optimum EBCT was 45 min.

• 한국산학기술학회논문지
• /
• 제8권1호
• /
• pp.136-142
• /
• 2007

최근 부영양화를 야기시키는 물질인 $PO_4^{3-}$ 이온을 제거하기 위해 고형반응물을 이용하는 것이 주목을 받고있다. 철광석의 정련 과정에서 생기는 슬래그는 용해된 무기 인산염을 폐수로부터 유리시켜 흡착 제거하는 것에 대한 근본적인 연구가 이루어져 왔다. 본 연구는 물 속의 인산염을 제거하기 위해 전로슬래그를 이용하였을 때 오랜 시간동안 hydroxyapatite 형태로 변화시켜 제거하고 인산염 제거를 향상시키기 위한 가능성을 찾기 위하여 여러 가지 조건을 변화시켜서 수행하였다. 본 연구 결과 전로슬래그를 이용한 등온흡착식을 적용했을 때 Freundlich 식을 적용할 수 있었으며, 인을 제거하는데 사용된 전로 슬래그의 크기는 $2{\sim}0.425mm$가 가장 적당한 것으로 나타났다. 특히, 연속반응탑을 이용할 경우, 유입수 농도가 1 mg/L일 때 80%까지 제거되는 것으로 나타났다.

• 공업화학
• /
• 제31권5호
• /
• pp.495-501
• /
• 2020

In this study, zirconium fumarate of metal-organic framework (MOF-801) was solvothermally synthesized at 130 ℃ and characterized through powder X-ray diffraction (PXRD) analyses and porosity measurements from N₂ sorption isotherms at 77 K. The ability of MOF-801 to act as an adsorbent for the phosphate removal from aqueous solutions at 25 ℃ was investigated. The phosphate removal efficiency (PRE) obtained by 0.05 g/L adsorbent dose at an initial phosphate concentration of 60 ppm after 3 h was 72.47%, whereas at 5 and 20 ppm, the PRE was determined to be 100% and 89.88%, respectively, after 30 min for the same adsorbent dose. Brunauer-Emmett-Teller (BET) surface area and pore volume of the bare MOF-801 sample were 478.25 ㎡/g and 0.52 ㎤/g, respectively, whereas after phosphate adsorption (at an initial concentration of 60 ppm, 3 h), the BET surface area and pore volume were reduced to 331.66 ㎡/g and 0.39 ㎤/g, respectively. The experimental data of kinetic (measured at initial concentrations of 5, 20 and 60 ppm) and isotherm measurements followed the pseudo-second-order kinetic equation and the Freundlich isotherm model, respectively. This study demonstrates that MOF-801 is a promising material for the removal of phosphate from aqueous solutions.

• 상하수도학회지
• /
• 제30권6호
• /
• pp.663-671
• /
• 2016

Coagulation/precipitation process has been widely used for the removal of phosphate within domestic wastewater. Although Fe and Al are typical coagulants used for phosphate removal, these have some shortages such as color problem and low sedimentation velocity. In this study, both Fe and Al were used to overcome the shortages caused by using single one, and anionic polymer coagulant was additionally used to enhance sedimentation velocity of the precipitate formed. Batch experiments using a jar test were conducted with real wastewater, which was an effluent of the second sedimentation tank in domestic wastewater treatment plant. Response Surface Methodology was used to examine the responsibility of each parameter on phosphate removal as well as to optimize the dosage of the three coagulants. Economic analysis was also done on the basis of selling prices of the coagulants in the field. Phosphate removal efficiency of Fe(III) was 30% higher than those of Fe(II). Considering chemical price, optimum dosage for achieving residual phosphate concentration below 0.2 mg/L were determined to be 18.14 mg/L of Fe(III), 2.60 mg/L of Al, and 1.64 mg/L of polymer coagulant.

• Environmental Engineering Research
• /
• 제17권3호
• /
• pp.133-138
• /
• 2012

Polyvinyl alcohol/alginate hydrogel beads containing Mg-Al layered double hydroxide (LDH-PVA/alginate beads) were synthesized for phosphate removal. Results showed that blending PVA with the LDH-alginate beads significantly improved their stability in a phosphate solution. The kinetic reaction in LDH-PVA/alginate beads reached equilibrium at 12 hr-post reaction with 99.2% removal. The amount of phosphate removed at equilibrium ($q_e$) was determined to be 0.389 mgP/g. The equilibrium data were described well by the Freundlich isotherm with the distribution coefficient ($K_F$, 0.638) and the constant (n, 0.396). Phosphate removal in LDH-PVA/alginate beads was not sensitive to solution pH. Also, the removal capacity of LDH-PVA/alginate beads ($q_e$, 1.543 mgP/g) was two orders of magnitude greater than that of PVA/alginate beads ($q_e$, 0.016 mgP/g) in column experiments. This study demonstrates that LDH-PVA/alginate beads with a higher chemical stability against phosphate compared to LDH-alginate beads have the potential for phosphate removal as adsorptive media.

• 상하수도학회지
• /
• 제29권5호
• /
• pp.565-573
• /
• 2015

The influencing factors to remove phosphate were evaluated by converter slag (CS). Experiments were performed by batch tests using different CS sizes and column test. Solutions were prepared at the different pH and concentrations. The maximum removal efficiency was obtained over 98% with the finest particle size, $CS_a$ within 2 hours in batch tests. The removal efficiency was increased in the order of decreasing size with same amount of CS for any pH of solutions. The adsorption data were well fitted to Freundlich isotherm. From the column experiment, the specific factors were revealed that the breakthrough removal capacity (BRC) $x_b/m_{cs}$, was decreased by increasing the influent concentration. The breakthrough time, tb was lasted shorter as increasing the influent concentration. The pH drop simultaneously led to lower BRC drop during the experimental hours. The relation between the breakthrough time and the BRC to influent concentration was shown in the logarithmic decrease. Results suggested that the large surface area of CS possessed a great potential for adsorptive phosphate removal. Consequently particle size and initial concentration played the major influencing factors in phosphate removal by converter slag.

• 상하수도학회지
• /
• 제21권3호
• /
• pp.273-278
• /
• 2007

Modern society has moved from a phosphorus recycling loop, where animal manure and human wastes were spread on farming land to recycle nutrients, to a once-through system, where phosphates are extracted from mined, non-renewable phosphate rock and end up either in landfill(sewage sludge, incinerator ash) or in surface waters. In this research, crystallization of nitrogen and phosphate with natural sources of $Mg^{2+}$ in synthetic water was tested. The operational parameters of pH, mixing time, and the magnesium molar ratio were investigated to find optimal conditions of the MAP precipitation using synthetic wastewater. The removal efficiency of phosphate increased with pH up to 11. By MAP precipitaiton of the synthetic waste water, 94% of the phosphate were eliminated at pH 11. It was found that at least 10 minutes mixing time was required and 20 minutes mixing time was recommended for efficient phosphate removal. High efficiency removal of phosphate was possible when the magnesium molar ratio was 1.0~2.0. The comparative study of different magnesium sources showed that coagulants (PAC) was the more efficient sources than only magnesium. The result showed that 97% of phosphate removal. In conclusion, coagulants (PAC) induced crystallization of struvite and hydroxyapatite was shown to be a technically viable process that could prove cost effective for removing phosphate in wastewater.

• 상하수도학회지
• /
• 제32권3호
• /
• pp.253-259
• /
• 2018

Cu(II) can cause health problem for human being and phosphate is a key pollutant induces eutrophication in rivers and ponds. To remove of Cu(II) and phosphate from solution, chitosan as adsorbent was chosen and used as a form of hydrogel bead. Due to the chemical instability of hydrogel chitosan bead (HCB), the crosslinked HCB by glutaraldehyde (GA) was prepared (HCB-G). HCB-G maintained the spherical bead type at 1% HCl without a loss of chitosan. A variety of batch experiment tests were carried out to determine the removal efficiency (%), maximum uptake (Q, mg/g), and reaction rate. In the single presence of Cu(II) or phosphate, the removal efficiency was obtained to 17 and 16%, respectively. However, the removal efficiency of Cu(II) and phosphate was increased to 50~55% at a mixed solution. The maximum uptake (Q) for Cu(II) and phosphate was enhanced from 11.3 to74.4 mg/g and from 3.34 to 36.6 mg/g, respectively. While the reaction rate of Cu(II) and phosphate was almost finished within 24 and 6 h at single solution, it was not changed for Cu(II) but was retarded for phosphate at mixed solution.