Chemical Stabilization of Bottom Ash from Municipal Solid Waste Incineration and Prediction of DOC Leaching in Landfill Sites

It is well known that it takes long time to stabilize landfill and meet the standard for leachate after landfilling is stopped. Moreover, the time required to meet the standard is not predicted. In this research, the rapid small-scale column test (RSSCT) was applied and was found to predict the dissolved organic carbon (DOC) leaching from municipal solid waste incineration bottom ash in a simulated landfill site. Acid washing with hydrochloric acid remarkably reduced the DOC leaching from bottom ash. According to the RSCCT, it was estimated that the acid washing would reduce the time for DOC stabilization of bottom ash by about 80% in a simulated landfill situation.It is well known that it takes long time to stabilize landfill and meet the standard for leachate after landfilling is stopped. Moreover, the time required to meet the standard is not predicted. In this research, the rapid small-scale column test (RSSCT) was applied and was found to predict the dissolved organic carbon (DOC) leaching from municipal solid waste incineration bottom ash in a simulated landfill site. Acid washing with hydrochloric acid remarkably reduced the DOC leaching from bottom ash. According to the RSCCT, it was estimated that the acid washing would reduce the time for DOC stabilization of bottom ash by about 80% in a simulated landfill situation

Isolation and characterization of coagulant extracted from moringa oleifera seed by salt solution

It is known that M. oleifera contains a natural coagulant in the seeds. In our previous research, the method using salt water to extract the active coagulation component from M. oleifera seeds was developed and compared with the conventional method using water. In this research, the active coagulation component was purified from a NaCl solution crude extract of Moringa oleifera seeds. The active component was isolated and purified from the crude extract through a sequence of steps that included salting-out by dialysis, removal of lipids and carbohydrates by homogenization with acetone, and anion exchange. Specific coagulation activity of the active material increased up to 34 times more than the crude extract after the ion exchange. The active component was not the same as that of water extract. The molecular weight was about 3000 Da. The Lowry method and the phenol-sulfuric acid method indicated that the active component was neither protein nor polysaccharide. The optimum pH of the purified active component for coagulation of turbidity was pH 8 and above. Different from the conventional water extracts, the active component can be used for waters with low turbidity without increase in the dissolved organic carbon concentration

Coagulation mechanism of salt solution-extracted active component in Moringa oleifera seeds

This study focuses on the coagulation mechanism by the purified coagulant solution (MOC-SC-PC) with the coagulation active component extracted from M. oleifera seeds using salt solution. The addition of MOC-SC-PC into tap water formed insoluble matters. The formation was responsible for kaolin coagulation. On the other hand, insoluble matters were not formed when the MOC-SC-PC was added into distilled water. The formation was affected by Ca2+ or other bivalent cations which may connect each molecule of the coagulation active component in MOC-SC-PC and form netlike structure. The coagulation mechanism of MOC-SC-PC seemed to be an enmeshment by the insoluble matters with netlike structure. In case of Ca2+ ion (bivalent cations), at least 0.2mM was necessary for coagulation at 0.3 mg-C l-1 dose of MOC-SC-PC. Other coagulation mechanisms like compression of double layer, interparticle bridging or charge neutralization were not responsible for the coagulation by MOC-SC-PC

Improvement of extraction method of coagulation active components from Moringa oleifera seed

A new method for the extraction of the active coagulation component from Moringa oleifera seeds was developed and compared with the ordinary water extraction method (MOC–DW). In the new method, 1.0 mol l-1 solution of sodium chloride (MOC–SC) and other salts were used for extraction of the active coagulation component. Batch coagulation experiments were conducted using 500 ml of low turbid water (50 NTU). Coagulation efficiencies were evaluated based on the dosage required to remove kaolinite turbidity in water. MOC–SC showed better coagulation activity with dosages 7.4 times lower than that using MOC–DW for the removal of kaolinite turbidity. MOC–SC could effectively coagulate more than 950f the 50 NTU initial kaolin turbidity using only 4 ml l-1, while 32 ml l-1 of MOC–DW could only remove about 781023440400f the same kaolin turbidity. The improvement of coagulation efficiency by NaCl is apparently due to the salting-in mechanism in proteins wherein a salt increases protein–protein dissociations, leading to increasing protein solubility as the salt ionic strength increases. There was no difference in the coagulation efficiency observed for extracts using any of four 1:1 salts (NaCl, KNO3, KCl and NaNO3) in our study. Purification and isolation of the active component confirmed that the active component of MOC–SC was mainly protein

ポリシリカ鉄凝集剤を用いた凝集沈澱-急速ろ過処理の特性

本研究では水道用湖沼原水を対象にした一年間のパイロットプラントを用いた実証試験で、ポリシリカ鉄凝集剤(PSI)の凝集沈澱処理能力をポリ塩化アルミニウム(PAC)および塩化鉄と比較、評価した。PSIの濁度除去能は同じ鉄系凝集剤である塩化鉄と比べて水温の影響を受けにくく、水質変動に対してもPACと同様に安定した処理能力を示した。PSIの藻類除去能はPAC、塩化鉄より高いと考えられた。これはPSIが鉄系凝集剤であることに起因していることと、重合ケイ酸の効果により低水温期でも塩化鉄のように処理能力が悪化することが無かった為と考えられた。ろ過水の残留濁度および全藻類数はPSI、塩化鉄、PACの3つの凝集剤による違いはほとんどなかったが、PSIを使用した場合にはアンスラサイト層で特異的な損失の増加が起こり、PACや塩化鉄を使用した場合に比べてろ過塔の総損失水頭が高くなった。この損失の増加の原因としては、凝集沈殿処理水に残留したPSI由来の溶存の重合ケイ酸が、アンスラサイト表面に吸着して蓄積することにより、アンスラサイト層の空隙を閉塞することが考えられた。The objective of this study is to evaluate polysilicate-iron (PSI) coagulant in comparison with polyaluminum chloride (PAC) and ferric chloride coagulants on turbidity and algae removal. The evaluation was carried out using a pilot scale plant for a lake water in a year. Turbidity removal by PSI was not affected by water temperature, whereas that by ferric chloride deteriorated in winter. PSI showed higher removal efficiency for algae than PAC in all seasons and ferric chloride in winter. This higher removal efficiency by PSI might be explained by the fact that PSI was a ferric coagulant and contained polysilicate. The water quality of filtrated water with rapid filtration, was almost the same. The total head loss of rapid filtration in PSI was developed quicker than that in PAC and ferric chloride due to high head loss in the anthracite layer. The adsorption and accumulation of dissolved polysilicate remaining from the water coagulated by PSI onto the anthracite would cause the high head loss development

Improvement of thermal hydrolysis rate of dichloroacetic acid using alcohol

Dichloroacetic acid (DCAA) is produced during the oxidation of trichloroethylene. It is also produced in drinking water treatment as a disinfection by-product. DCAA is a problem material, because of its toxicity. The objective of this research is to find the final products and the reaction pathway of the DCAA decomposition by hydrolysis, and to increase the hydrolysis rate. The removal of both chlorine atoms in DCAA structure was achieved with hydrolysis at around 75 °C, and the final products were oxalic acid and glycolic acid. The reaction pathway was the production of oxalic acid and glycolic acid from two glyoxylic acid molecules by Cannizzaro reaction after the glyoxylic acid production from dechlorination of DCAA with hydrolysis. The hydrolysis rate of DCAA was increased with the use of 90 1.140250e-268thanol solution as solvent. The activation energy of DCAA was about 80 kJ/mol in it, while it was around 105 kJ/mol in water

EFFECTS OF PRETREATMENTS ON CALCIUM ACCUMULATION ONTO GAC

The effect of coagulation and ozonation as pretreatments for granular activated carbon (GAC) filtration on calcium accumulation onto GAC was studied. Three kinds of FA solutions extracted from commercial leaf mold for horticulture were used: FA itself, FA after coagulation (FA-c) and FA after ozonation (FA-oz). Coagulation used as pretreatment before GAC filtration significantly decreased calcium accumulation onto GAC while ozonation caused a small increase on calcium accumulation onto GAC. Acidic functional groups into GAC introduced by adsorption of fulvic acid controlled accumulation of calcium onto GAC. Significant decrease of calcium accumulation onto GAC by coagulation was caused by the removal of the fraction with acidic functional groups from FA.The effect of coagulation and ozonation as pretreatments for granular activated carbon (GAC) filtration on calcium accumulation onto GAC was studied. Three kinds of FA solutions extracted from commercial leaf mold for horticulture were used: FA itself, FA after coagulation (FA-c) and FA after ozonation (FA-oz). Coagulation used as pretreatment before GAC filtration significantly decreased calcium accumulation onto GAC while ozonation caused a small increase on calcium accumulation onto GAC. Acidic functional groups into GAC introduced by adsorption of fulvic acid controlled accumulation of calcium onto GAC. Significant decrease of calcium accumulation onto GAC by coagulation was caused by the removal of the fraction with acidic functional groups from FA

Improvement of extraction method of coagulation active components from Moringa oleifera seed

ABSTRACT A new method for the extraction of the active coagulation component from Moringa oleifera seeds was developed and compared with the ordinary water extraction method (MOC-DW). In the new method, 1.0 mol l -1 solution of sodium chloride (MOC-SC) and other salts were used for extraction of the active coagulation component. Batch coagulation experiments were conducted using 500 ml of low turbid water (50 NTU). Coagulation efficiencies were evaluated based on the dosage required to remove kaolinite turbidity in water. MOC-SC showed better coagulation activity with dosages 7.4 times lower than that using MOC-DW for the removal of kaolinite turbidity. MOC-SC could effectively coagulate more than 95% of the 50 NTU initial kaolin turbidity using only 4 ml l -1 , while 32 ml l -1 of MOC-DW could only remove about 78% of the same kaolin turbidity. The improvement of coagulation efficiency by NaCl is apparently due to the salting-in mechanism in proteins wherein a salt increases protein-protein dissociations leading to increasing protein solubility as the salt ionic strength increases. There was no difference in the coagulation efficiency observed for extracts using any of four 1:1 salts (NaCl, KNO3, KCl and NaNO3) in our study. Purification and isolation of the active component confirmed that the active component of MOC-SC was mainly protein