Evaluation of a hybrid constructed wetland for treating domestic sewage from individual housing units surrounding agricultural villages in South Korea

Seo, Dong Cheol,DeLaune, Ronald D.,Park, Woo Young,Lim, Jong Sir,Seo, Jeoung Yoon,Lee, Do Jin,Cho, Ju Sik,Heo, Jong Soo Royal Society of Chemistry 2009 Journal of environmental monitoring Vol.11 No.1

<P>The treatment efficiency of 2- and 3-stage constructed wetlands (CWs) was evaluated for treating domestic sewage from houses surrounding agricultural villages. The optimum depth of filter media was 90 cm. The optimum volume ratio of vertical flow (VF) and horizontal flow (HF) beds was 1:2, and the optimum filter medium was broken stone in the VF-HF 2-stage hybrid CWs. Based on the above optimum conditions, removal efficiency of biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), total nitrogen (T-N), and total phosphorus (T-P) were 99, 98, 99, 68, and 72%, respectively. However to utilize constructed wetlands (CWs) for treating domestic sewage for an individual house, would require downsizing of the 2-stage hybrid CWs. In addition, the low removal efficiency of T-N and T-P in 2-stage hybrid CWs would require improvements necessary to meet acceptable water quality discharge standards. Thus, to reduce the CWs’ area and improve the T-N and T-P removal efficiencies, VF-HF 2-stage hybrid CW was modified into VF/HF(I)-HF(II) and VF/HF(I)-HF(III) 3-stage hybrid CW. The optimum reduced size of 3-stage hybrid CW was the VF/HF(I)-HF(II) configuration which also increased T-N removal. Using this system, removal efficiency of BOD, COD, SS, T-N, and T-P were 99, 98, 99, 83, and 75%, respectively. In VF/HF(I)-HF(II) CW, the removal velocity of BOD, COD and SS was rapid on the order of VF (1<SUP>st</SUP> stage) ≫ HF(II) (3<SUP>rd</SUP> stage) ≥ HF(I) (2<SUP>nd</SUP> stage), VF (1<SUP>st</SUP> stage) ≫ HF(II) (3<SUP>rd</SUP> stage) > HF(I) (2<SUP>nd</SUP> stage) and VF (1<SUP>st</SUP> stage) ≫ HF(I) (2<SUP>nd</SUP> stage) > HF(II) (3<SUP>rd</SUP> stage), respectively. The removal velocity of T-N and T-P in VF/HF(I)-HF(II) CWs was rapid on the order of HF(I) (2<SUP>nd</SUP> stage) > HF(II) (3<SUP>rd</SUP> stage) ≥ VF (1<SUP>st</SUP> stage) and VF (1<SUP>st</SUP> stage) > HF(I) (2<SUP>nd</SUP> stage) > HF(II) (3<SUP>rd</SUP> stage), respectively.</P> <P>Graphic Abstract</P><P>To effectively treat domestic sewage from individual houses surrounding agricultural villages, the optimum hybrid constructed wetlands was demonstrated to be the VF/HF(I)-HF(II) 3-stage constructed wetlands configuration. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b806017g'> </P>

Removal of Eriochrome Black T by sulfate radical generated from Fe-impregnated biochar/persulfate in Fenton-like reaction

박종환,Jim J. Wang,Negar Tafti,Ronald D. Delaune 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.71 No.-

A new heterogeneous Fenton catalyst, Fe-impregnated biochar catalyst (Fe-BC) was synthesized andevaluated in detail for its catalytic activity with sulfate radical under various conditions. The optimumconditions for the removal of Eriochrome Black T (EBT) by Fe-BC were determined as 0.27 g/L K2S2O8 (PS)and 0.5 g/L Fe-BC for 0.1 g/L EBT, and which resulted 85–88% removal efficiency within 2 h. The effectiveoxidation of EBT was observed over a pH range of 2–4 and temperature of 25–45 C and maintained EBTremoval efficiency of 77.6–92.7%. Under optimum conditions, the catalytic activity was faster in the orderof PS > PS + HP > H2O2 (HP) >>Fe-BC (without oxidants). The catalytic activity of Fe-BC for EBT can beidentified in two stages, which occur rapidly within 30 min (1st stage) and followed by slow oxidationuntil 120 min (2nd stage). Catalytic activity by sulfate radical was also dominantly influenced by otherpollutant such as iodide, phosphate and humic acid. Overall, the sulfate radical generated from Fe-BC/PSwas found more economical with strong oxidation efficiency for use in Fenton-like reaction for treatingorganic pollutants compared with conventional Fenton reaction with H2O2.

Characteristics of biochars derived from fruit tree pruning wastes and their effects on lead adsorption

박종환,옥용식,김성헌,강세원,조주식,허종수,Ronald D. Delaune,서동철 한국응용생명화학회 2015 Applied Biological Chemistry (Appl Biol Chem) Vol.58 No.5

The aim of this study was to evaluate the biochar characteristics derived from fruit tree pruning wastes (FTPW) and their effects on lead (Pb) adsorption. Based on results from Pb adsorption, surface area, and phosphorus content, the optimum pyrolysis temperature was 600 C for Pb adsorption capacity. Using the Freundlich isotherm, the Pb adsorption capacity (K) of biochar obtained from various FTPW decreased in the order of pear (3.8001) persimmon (2.3977) C apple (2.1968). Based on the Langmuir adsorption isotherm, the maximum Pb adsorption capacities (a; mg g-1) of biochar obtained from different FTPW were in the following order: pear (26.2) persimmon (19.9) C apple (17.7). The maximum Pb adsorption capacity of the pruned pear tree waste biochar was greater than the other FTPW biochars. Pruned apple tree waste biochar had the lowest Pb adsorption capacity among the tested FTPW biochars. The positive correlation between the Langmuir maximum adsorption capacity (LM) values of the biochars and their phosphorus content and surface area indicated difference in adsorption capacity. However, adsorption capacity of the biochar from all FTPW studied could be used for removing Pb and other metal from wastewater.

Phosphate removal in constructed wetland with rapid cooled basic oxygen furnace slag

Park, Jong-Hwan,Wang, Jim J.,Kim, Seong-Heon,Cho, Ju-Sik,Kang, Se-Won,Delaune, Ronald D.,Seo, Dong-Cheol Elsevier 2017 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.327 No.-

<P><B>Abstract</B></P> <P>The objective of this study was to evaluate adsorption characteristics of phosphate by rapid cooled basic oxygen furnace slag (RC-BOFS) through various conditions and removal rate of phosphate in small-scale constructed wetland with RC-BOFS as filter material. The phosphate adsorption by RC-BOFS was rapid in the first 0.5h and the pseudo-second-order kinetic model fit the data better than the pseudo-first-order kinetic model. The maximum phosphate adsorption capacities of RC-BOFS under different pH were in the following order: 3.57mgPg<SUP>−1</SUP> (pH 5)>2.47mgPg<SUP>−1</SUP> (pH 7)>1.46mgPg<SUP>−1</SUP> (pH 9). Small-size RC-BOFS (0.8–2.3mm) was more efficient with 23% higher phosphate adsorption than big-size RC-BOFS (2.3–4.6mm). Characterization of RC-BOFS before and after phosphate adsorption by XRD, FTIR and SEM-EDS indicated that phosphate adsorption by RC-BOFS was dominated by metal oxide and precipitation by calcium and was closely related to the slag chemical properties. The phosphate saturation time in constructed wetland with coarse sand was predicted about 292days, whereas the longevity of constructed wetland with adding about 25% RC-BOFS to the coarse sand can significantly increase up to 1349days. It was concluded that the horizontal flow constructed wetland with sand 75%:RC-BOFS 25% ratio could achieve high phosphate removal rate and near-neutral pH for meeting the acceptable water quality discharge standard from water treatment plant.</P> <P><B>Highlights</B></P> <P> <UL> <LI> RC-BOFS was an effective adsorbent for phosphate. </LI> <LI> Contact time, initial concentration and pH value affect the adsorption capacity. </LI> <LI> Adsorption mechanisms were well described by SEM-EDS, XRD and FTIR. </LI> <LI> High phosphate adsorption capacity and near-neutral pH was observed in CW with sand and RC-BOFS. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Adsorption of Cd, Cu and Zn from aqueous solutions onto ferronickel slag under different potentially toxic metal combination

Park, Jong-Hwan,Kim, Seong-Heon,Kang, Se-Won,Kang, Byung-Hwa,Cho, Ju-Sik,Heo, Jong-Soo,Delaune, Ronald D.,Ok, Yong Sik,Seo, Dong-Cheol IWA Publishing 2016 Water Science & Technology Vol.73 No.5

<P>Adsorption characteristics of potentially toxic metals in single-and multi-metal forms onto ferronickel slag were evaluated. Competitive sorption of metals by ferronickel slag has never been reported previously. The maximum adsorption capacities of toxic metals on ferronickel were in the order of Cd (10.2 mg g(-1)) > Cu (8.4 mg g(-1)) > Zn (4.4 mg g(-1)) in the single-metal adsorption isotherm and Cu (6.1 mg g(-1)) >> Cd (2.3 mg g(-1)) > Zn (0.3 mg g(-1)) in the multi-metal adsorption isotherm. In comparison with single-metal adsorption isotherm, the reduction rates of maximum toxic metal adsorption capacity in the multi-metal adsorption isotherm were in the following order of Zn (93%) > Cd (78%) >> Cu (27%). The Freundlich isotherm provides a slightly better fit than the Langmuir isotherm equation using ferronickel slag for potentially toxic metal adsorption. Multi-metal adsorption behaviors differed from single-metal adsorption due to competition, based on data obtained from Freundlich and Langmuir adsorption models and three-dimensional simulation. Especially, Cd and Zn were easily exchanged and substituted by Cu during multi-metal adsorption. Further competitive adsorption studies are necessary in order to accurately estimate adsorption capacity of ferronickel slag for potentially toxic metals in natural environments.</P>

Characteristics of biochars derived from fruit tree pruning wastes and their effects on lead adsorption

Park, Jong Hwan,Ok, Yong Sik,Kim, Seong Heon,Kang, Se Won,Cho, Ju Sik,Heo, Jong Soo,Delaune, Ronald D.,Seo, Dong Cheol The Korean Society for Applied Biological Chemistr 2015 Applied Biological Chemistry (Appl Biol Chem) Vol.58 No.5

The aim of this study was to evaluate the biochar characteristics derived from fruit tree pruning wastes (FTPW) and their effects on lead (Pb) adsorption. Based on results from Pb adsorption, surface area, and phosphorus content, the optimum pyrolysis temperature was $600^{\circ}C$ for Pb adsorption capacity. Using the Freundlich isotherm, the Pb adsorption capacity (K) of biochar obtained from various FTPW decreased in the order of pear (3.8001) ${\gg}$ persimmon (2.3977) ${\geq}$ apple (2.1968). Based on the Langmuir adsorption isotherm, the maximum Pb adsorption capacities (a; mg $g^{-1}$) of biochar obtained from different FTPW were in the following order: pear (26.2) ${\gg}$ persimmon (19.9) ${\geq}$ apple (17.7). The maximum Pb adsorption capacity of the pruned pear tree waste biochar was greater than the other FTPW biochars. Pruned apple tree waste biochar had the lowest Pb adsorption capacity among the tested FTPW biochars. The positive correlation between the Langmuir maximum adsorption capacity ($L_M$) values of the biochars and their phosphorus content and surface area indicated difference in adsorption capacity. However, adsorption capacity of the biochar from all FTPW studied could be used for removing Pb and other metal from wastewater.

Recycling of rice straw through pyrolysis and its adsorption behaviors for Cu and Zn ions in aqueous solution

Park, Jong-Hwan,Wang, Jim J.,Kim, Seong-Heon,Cho, Ju-Sik,Kang, Se-Won,Delaune, Ronald D.,Han, Kun-Jun,Seo, Dong-Cheol Elsevier 2017 Colloids and surfaces. A, Physicochemical and engi Vol.533 No.-

<P><B>Abstract</B></P> <P>Biochar has been suggested as new adsorbent for removing heavy metals from aqueous solutions. However, adsorption nature of biochar is influenced by feedstock-specific properties. In this study, experiments were performed to characterize the effect of cation exchange on adsorption behavior of Cu and Zn in single- and binary-metal systems by rice straw biochar (RSB) made by pyrolysis at 600°C. Result of kinetic experiment showed that the Cu and Zn in aqueous solution were rapidly adsorbed from the RSB in the first 2h and then reached the equilibrium after 4h. The fitting of intraparticale diffusion model showed fast Cu diffusion into boundary layer and pores of biochar than Zn. In parallel with 2.65meqL<SUP>−1</SUP> Cu and 1.79meqL<SUP>−1</SUP> Zn being adsorbed by RSB, up to 1.65 and 0.76meqL<SUP>−1</SUP> exchangeable cations were released into the solution, indicating that cation exchange could contribute 62.3 and 42.5% to Cu and Zn sorption by RSB. Langmuir maximum adsorption capacities (<I>a</I>) of RSB for Cu and Zn were 56.5 and 38.6mgg<SUP>−1</SUP> in single-metal system and 40.2 and 7.9mgg<SUP>−1</SUP> in binary-metal system, respectively. Overall, the results demonstrate that the Cu and Zn adsorption by RSB was closely related to the exchangeable cation. The application of RSB could be especially attractive when considering biochar with high cation exchange capacities.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Long-term performance of vertical-flow and horizontal-flow constructed wetlands as affected by season, N load, and operating stage for treating nitrogen from domestic sewage

Kim, Seong-Heon,Cho, Ju-Sik,Park, Jong-Hwan,Heo, Jong-Soo,Ok, Yong-Sik,Delaune, Ronald D.,Seo, Dong-Cheol Springer-Verlag 2016 Environmental Science and Pollution Research Vol.23 No.2

<P>To investigate the long-term nitrogen treatment efficiency in vertical-flow (VF)-horizontal-flow (HF) hybrid constructed wetlands (CWs), the nitrogen removal efficiency under different seasons, N loads, and three operating stages (representing age of the wetland) were evaluated over a 12-year period. The average total nitrogen (TN) removal efficiencies in the effluent during the operation period were in the following order: summer (75.2 %) > spring (73.4 %) a parts per thousand'aEuro parts per thousand autumn (72.6 %) > winter (66.4 %). The removal efficiencies of TN in summer, autumn, and spring were generally higher than those in winter. At different stages of operation (years), the average TN removal rates in the effluent were in the following order: middle stage (73.4 %; years 2006-2009) > last stage (72.0 %; years 2010-2013) > beginning stage (70.1 %; years 2002-2005). In VF-HF CWs, the amount of average TN removal (mg N m(-2) day(-1)) over the 12-year period was in the order of summer (5.5) a parts per thousand'aEuro parts per thousand autumn (5.1) > spring (4.3) a parts per thousand'aEuro parts per thousand winter (4.2) for the VF bed and in the order of summer (3.5) a parts per thousand'aEuro parts per thousand spring (3.5) a parts per thousand'aEuro parts per thousand autumn (3.3) > winter (2.7) for the HF bed, showing that the amount of TN removal per unit area (m(2)) in summer was slightly greater than that in other seasons. The amount of TN removal in the VF bed was slightly greater than that in the HF bed. Using three-dimensional simulation graphs, the maximum TN removal rate was at inflow N loads below 2.7 g m(-2) day(-1) in the summer season, whereas the minimum TN removal rate was at inflow N loads below 1.4 g m(-2) day(-1) in the winter season. Consequently, the TN removal efficiency was very stable over the 12 years of operation in VF-HF hybrid CWs. Results demonstrate that the VF-HF hybrid CWs possess good buffer capacity for treating TN from domestic sewage for extended periods of time.</P>