Wan Zuhairi Yaacob

There is an urgent need for characterization of leachate arising from waste disposal to ensure a corresponding effective leachate management policy. Field and laboratory studies have been carried out to investigate the impact of municipal landfill leachate on the underlying groundwater at a site in West Malaysia. The solid waste was disposed of directly onto an unprotected natural soil formation. This situation was made worse by the shallow water table. The hydrochemical composition of groundwater in the vicinity of the site (background) is a dilute mixed cation, bicarbonate water. The high ionic balance error of ~13.5% reveals that the groundwater body underneath the site was a highly contaminated leachate rather than contaminated groundwater. Elevated concentration of chloride (355.48 mg/L), nitrate (10.40 mg/L as NO3), nitrite (14.59 mg/L), ammoniacal-N (11.61 mg/L), sodium (227.56 mg/L), iron (0.97 mg/L), and lead (0.32 mg/L) measured downgradient indicate that the contamination plume has migrated further away from the site. In most cases, the concentration of these contamination indicators, together with the ranges of sodium percentage (66.3–89.9%) and sodium adsorption ratio (10.1–19.7%), were found to be considerably higher than the limit values of safe water for both domestic and irrigation purposes, respectively. Les lixiviats issus du traitement des déchets doivent d’urgence être caractérisés pour permettre une politique appropriée de gestion de ces lixiviats. Des études de terrain et de laboratoire ont été conduites pour reconnaitre l’impact des lixiviats des décharges municipales sur les eaux souterraines sous-jacentes sur un site de Malaisie occidentale. Les déchets solides ont y été entreposés directement sur le sol naturel non protégé. La situation a été aggravée par le niveau peu profond de la nappe. La composition hydrochimique des eaux souterraines dans le voisinage du site (contexte) montre une eau bicarbonatée à divers cations. L’erreur forte ~13.5% sur la balance ionique révèle que la masse d’eau souterraine au droit du site était un lixiviat très contaminé plutôt que de l’eau souterraine contaminée. Les concentrations élevées en chlorures (355.48 mg/L), en nitrate (10.40 mg/L de NO3), en nitrite (14.59 mg/L), en azote ammoniacal (11.61 mg/L), en sodium (227.56 mg/L), en fer (0.97 mg/L), et en plomb (0.32 mg/L) mesurées à l’aval hydraulique indiquent que le plume de contamination a migré bien au-delà du site. Dans la plupart des cas, la concentration de ces indicateurs de contamination, de même que les intervalles de pourcentage de sodium (66.3–89.9%) et du ratio adsorption du sodium (10.1–19.7%), sont apparus très supérieurs aux valeurs limites pour les eaux respectivement à usage domestique et d’irrigation. Existe una necesidad urgente de caracterizar los lixiviados provenientes de la disposición de los residuos para asegurar una correspondiente política de manejo efectivo de los lixiviados. Se han llevado a cabo estudios de laboratorio y de campo para investigar el impacto del lixiviado de un relleno municipal sobre el agua subterránea subyacente en un sitio en Malasia occidental. El residuo sólido fue dispuesto directamente sobre una formación de suelo natural no protegido. Esta situación empeoró por el nivel freático somero. La composición hidroquímica de las aguas subterráneas (de fondo) en la vecindad del sitio es un agua diluida mixta bicarbonatada catiónica. El alto error del balance iónico de ~13.5% revela que el cuerpo de agua subterránea subyacente del sitio fue un lixiviado altamente contaminado más bien que un agua subterránea contaminada. Las elevadas concentraciones de cloruro (355.48 mg/L), nitrato (10.40 mg/L como NO3), nitrito (14.59 mg/L), N- amoniacal (11.61 mg/L), sodio (227.56 mg/L), hierro (0.97 mg/L), y plomo (0.32 mg/L) medidas gradiente abajo indican que la pluma de contaminación ha migrado más allá del sitio. En la mayoría de los casos se encontró que la concentración de estos indicadores de contaminación, conjuntamente con los intervalos del porcentaje de sodio (66.3–89.9%) y de la relación adsorción sodio (10.1–19.7%), eran considerablemente más altos que los valores límites de seguridad del agua para tanto propósitos domésticos como de irrigación. 目前急需对废物处置中产生的沥出液进行刻画的方法, 以制定有效的沥出液管理政策。本文对西马来西亚的一处场地开展了现场研究和实验室研究, 以调查城市垃圾填埋场沥出液对下伏地下水的影响。固体垃圾直接填埋于没有防护措施的天然土壤层之上。由于地下水位很浅, 情况变得更糟。场地附近地下水的水化学成分 (背景值) 是低浓度的混合阳离子, 重碳酸水。高达 ~13.5%的离子平衡误差表明, 填埋场下的地下水体与其说是受污染的地下水不如说是高度污染的沥滤液。在下游测量的氯化物 (355.48 mg/L), 硝酸盐 (10.40 mg/L, NO3), 亚硝酸盐 (14.59 mg/L), 氨氮 (11.61 mg/L), 钠 (227.56 mg/L), 铁 (0.97 mg/L) 和铅 (0.32 mg/L) 浓度增加, 表明污染晕已从填埋场运移到远处。多数情况下, 这些污染指示物的浓度, 连同钠百分比的范围 (66.3–89.9%) 和钠吸附比 (10.1–19.7%), 远高于生活和灌溉安全用水的极限值。 Há uma urgente necessidade de caracterização dos lixiviados provenientes de lixeiras, a fim de assegurar uma efectiva política de gestão de lixiviados. Foram realizados estudos de campo e de laboratório para investigar o impacte dos lixiviados dos aterros municipais nas águas subterrâneas subjacentes, num local na Malásia Ocidental. Os resíduos sólidos foram depositados directamente sobre uma formação de solo natural não protegida, situação esta agravada pela presença de um nível freático pouco profundo. A composição hidroquímica de base da água subterrânea na vizinhança do local é bicarbonatada mista pouco mineralizada. O erro de balanço iónico elevado de ~13.5% revela que a massa de água subterrânea subjacente ao local é um lixiviado altamente contaminado, em vez de água subterrânea contaminada. As concentrações elevadas de cloreto (355.48 mg/L), nitrato (10.40 mg/L de NO3), nitrito (14.59 mg/L), azoto amoniacal (11.61 mg/L), sódio (227.56 mg/L), ferro (0.97 mg/L) e chumbo (0.32 mg/L) medidos a jusante do escoamento indicam que a pluma de contaminação já migrou para bastante longe do local do depósito de resíduos sólidos. Na maioria dos casos, a concentração destes indicadores de contaminação, em conjunto com os valores de percentagem de sódio (66.3–89.9%) e da taxa de adsorção em sódio (10.1–19.7%), revelou ser consideravelmente mais elevada que os valores limite de água segura, quer para uso doméstico, quer para rega.

There is an urgent need for characterization of leachate arising from waste disposal to ensure a corresponding effective leachate management policy. Field and laboratory studies have been carried out to investigate the impact of municipal landfill leachate on the underlying groundwater at a site in West Malaysia. The solid waste was disposed of directly onto an unprotected natural soil formation. This situation was made worse by the shallow water table. The hydrochemical composition of groundwater in the vicinity of the site (background) is a dilute mixed cation, bicarbonate water. The high ionic balance error of ~13.5% reveals that the groundwater body underneath the site was a highly contaminated leachate rather than contaminated groundwater. Elevated concentration of chloride (355.48 mg/L), nitrate (10.40 mg/L as NO3), nitrite (14.59 mg/L), ammoniacal-N (11.61 mg/L), sodium (227.56 mg/L), iron (0.97 mg/L), and lead (0.32 mg/L) measured downgradient indicate that the contamination plume has migrated further away from the site. In most cases, the concentration of these contamination indicators, together with the ranges of sodium percentage (66.3–89.9%) and sodium adsorption ratio (10.1–19.7%), were found to be considerably higher than the limit values of safe water for both domestic and irrigation purposes, respectively. Les lixiviats issus du traitement des déchets doivent d’urgence être caractérisés pour permettre une politique appropriée de gestion de ces lixiviats. Des études de terrain et de laboratoire ont été conduites pour reconnaitre l’impact des lixiviats des décharges municipales sur les eaux souterraines sous-jacentes sur un site de Malaisie occidentale. Les déchets solides ont y été entreposés directement sur le sol naturel non protégé. La situation a été aggravée par le niveau peu profond de la nappe. La composition hydrochimique des eaux souterraines dans le voisinage du site (contexte) montre une eau bicarbonatée à divers cations. L’erreur forte ~13.5% sur la balance ionique révèle que la masse d’eau souterraine au droit du site était un lixiviat très contaminé plutôt que de l’eau souterraine contaminée. Les concentrations élevées en chlorures (355.48 mg/L), en nitrate (10.40 mg/L de NO3), en nitrite (14.59 mg/L), en azote ammoniacal (11.61 mg/L), en sodium (227.56 mg/L), en fer (0.97 mg/L), et en plomb (0.32 mg/L) mesurées à l’aval hydraulique indiquent que le plume de contamination a migré bien au-delà du site. Dans la plupart des cas, la concentration de ces indicateurs de contamination, de même que les intervalles de pourcentage de sodium (66.3–89.9%) et du ratio adsorption du sodium (10.1–19.7%), sont apparus très supérieurs aux valeurs limites pour les eaux respectivement à usage domestique et d’irrigation. Existe una necesidad urgente de caracterizar los lixiviados provenientes de la disposición de los residuos para asegurar una correspondiente política de manejo efectivo de los lixiviados. Se han llevado a cabo estudios de laboratorio y de campo para investigar el impacto del lixiviado de un relleno municipal sobre el agua subterránea subyacente en un sitio en Malasia occidental. El residuo sólido fue dispuesto directamente sobre una formación de suelo natural no protegido. Esta situación empeoró por el nivel freático somero. La composición hidroquímica de las aguas subterráneas (de fondo) en la vecindad del sitio es un agua diluida mixta bicarbonatada catiónica. El alto error del balance iónico de ~13.5% revela que el cuerpo de agua subterránea subyacente del sitio fue un lixiviado altamente contaminado más bien que un agua subterránea contaminada. Las elevadas concentraciones de cloruro (355.48 mg/L), nitrato (10.40 mg/L como NO3), nitrito (14.59 mg/L), N- amoniacal (11.61 mg/L), sodio (227.56 mg/L), hierro (0.97 mg/L), y plomo (0.32 mg/L) medidas gradiente abajo indican que la pluma de contaminación ha migrado más allá del sitio. En la mayoría de los casos se encontró que la concentración de estos indicadores de contaminación, conjuntamente con los intervalos del porcentaje de sodio (66.3–89.9%) y de la relación adsorción sodio (10.1–19.7%), eran considerablemente más altos que los valores límites de seguridad del agua para tanto propósitos domésticos como de irrigación. 目前急需对废物处置中产生的沥出液进行刻画的方法, 以制定有效的沥出液管理政策。本文对西马来西亚的一处场地开展了现场研究和实验室研究, 以调查城市垃圾填埋场沥出液对下伏地下水的影响。固体垃圾直接填埋于没有防护措施的天然土壤层之上。由于地下水位很浅, 情况变得更糟。场地附近地下水的水化学成分 (背景值) 是低浓度的混合阳离子, 重碳酸水。高达 ~13.5%的离子平衡误差表明, 填埋场下的地下水体与其说是受污染的地下水不如说是高度污染的沥滤液。在下游测量的氯化物 (355.48 mg/L), 硝酸盐 (10.40 mg/L, NO3), 亚硝酸盐 (14.59 mg/L), 氨氮 (11.61 mg/L), 钠 (227.56 mg/L), 铁 (0.97 mg/L) 和铅 (0.32 mg/L) 浓度增加, 表明污染晕已从填埋场运移到远处。多数情况下, 这些污染指示物的浓度, 连同钠百分比的范围 (66.3–89.9%) 和钠吸附比 (10.1–19.7%), 远高于生活和灌溉安全用水的极限值。 Há uma urgente necessidade de caracterização dos lixiviados provenientes de lixeiras, a fim de assegurar uma efectiva política de gestão de lixiviados. Foram realizados estudos de campo e de laboratório para investigar o impacte dos lixiviados dos aterros municipais nas águas subterrâneas subjacentes, num local na Malásia Ocidental. Os resíduos sólidos foram depositados directamente sobre uma formação de solo natural não protegida, situação esta agravada pela presença de um nível freático pouco profundo. A composição hidroquímica de base da água subterrânea na vizinhança do local é bicarbonatada mista pouco mineralizada. O erro de balanço iónico elevado de ~13.5% revela que a massa de água subterrânea subjacente ao local é um lixiviado altamente contaminado, em vez de água subterrânea contaminada. As concentrações elevadas de cloreto (355.48 mg/L), nitrato (10.40 mg/L de NO3), nitrito (14.59 mg/L), azoto amoniacal (11.61 mg/L), sódio (227.56 mg/L), ferro (0.97 mg/L) e chumbo (0.32 mg/L) medidos a jusante do escoamento indicam que a pluma de contaminação já migrou para bastante longe do local do depósito de resíduos sólidos. Na maioria dos casos, a concentração destes indicadores de contaminação, em conjunto com os valores de percentagem de sódio (66.3–89.9%) e da taxa de adsorção em sódio (10.1–19.7%), revelou ser consideravelmente mais elevada que os valores limite de água segura, quer para uso doméstico, quer para rega.

In this study, column tests were used to determine the retention capability of three types of estuarine alluvia collected adjacent to landfill sites in South Wales. Selective sequential extraction (SSE) was used to study the retention mechanisms of heavy metals in the soil columns obtained from leaching experiments. Acid digestion was later used to check the validity of the SSE results. Breakthrough curves show good retention of heavy metal ions (Pb, Cu, and Zn) by all soils, where almost 99% of heavy metals were retained with the Ce/Co values in the order of 10−3. The retention strength of these soils was observed to be constant up to five pore volumes (PV). This corresponds with the pH of the effluents and pore water of soil slices, which also show good buffering capacity against very acidic leachate up to 5PV. The heavy metal extraction profiles from SSE show very similar trends with the retention profiles from the leaching experiments, where heavy metals were retained mainly at the top part where the leachate entered the column. SSE indicates qualitatively that heavy metals precipitated with carbonates and amorphous materials (oxides/hydroxides) are higher than heavy metal retention via exchangeable mechanisms. The mass balance calculation gives range of deviation of 1–16% of the total soil extraction. The distribution of the heavy metals with various soil constituents are ranked in the following order: Carbonates>Amorphous oxides hydroxides>Organic matter>Exchangeable phases.

This paper aims at determining of inorganic leachate contamination for a capped unsanitary landfill in the absence of hydrogeological data. The 2D geoelectrical resistivity imaging, soil physicochemical characterization, and surface water analysis were used to determine contamination load and extent of selective heavy metal contamination underneath the landfill. The positions of the contaminated subsoil and groundwater were successfully delineated in terms of low resistivity leachate plumes of <10 Ωm. Leachate migration towards the reach of Kelang River could be clearly identified from the resistivity results and elevated concentrations of Fe in the river downslope toe of the site. Concentration of Fe, Mn, Ca, Na, K, Mg, Cu, Cr, Co, Ni, Zn, and Pb was measured for the subsoil samples collected at the downslope (BKD), upslope (BKU), and the soil-waste interface (BKI), of the landfill. The concentration levels obtained for most of the analyzed heavy metals significantly exceed the normal range in typical municipal solid waste landfill sites. The measured heavy metal contamination load in the subsoil is in the following order Fe ≫ Mn > Zn > Pb > Cr > Cu. Taking into consideration poor physical and chemical characteristics of the local soil, these metals first seem to be attenuated naturally at near surface then remobilize unavoidably due to the soil acidic environment (pH 4.2-6.18) which in turn, may allow an easy washing of these metals in contact with the shallow groundwater table during the periodic fluctuation of the Kelang River. These heavy metals are believed to have originated from hazardous industrial waste that might have been illegally dumped at the site.

The sorption capacity of five clay soils from South Wales in the United Kingdom was investigated using two main tests; physico-chemical and batch equilibrium (BET). The physico-chemical property results show that soil weathered mudrocks (MR1), glacial till (GT1), and estuarine alluviums (NEA4, PEA3 and CEA3) are capable of being used as landfill liners and are chosen for further sorption tests. The batch tests (i.e. sorption tests) on soil suspension produce adsorption-pH curves, showing increasing adsorption at higher pH levels. The sorption data are also presented using adsorption isotherm curves and are best fitted using the Langmuir adsorption equation that yields the maximum adsorption capacity of the soils. The sorption capacity of soils are ranked as estuarine alluvium soils>glacial till>weathered mudrocks. Estuarine alluvium soils show a good buffering capacity and high sorption capability compared to glacial till and weathered mudrocks. The study also discovers that the maximum sorption capacities are highly influenced by the chemical properties of the soils.