Contributions to predicting contaminant leaching from secondary materials used in roads

Slags, coal ashes, and other secondary materials can be used in road construction. Both traditional and secondary materials used in roads may contain contaminants that may leach and pollute the groundwater. The goal of this research was to further the understanding of leaching and transport of contaminants from pavement materials. Towards this goal, a new probabilistic framework was introduced which provided a structured guidance for selecting the appropriate model, incorporating uncertainty, variability, and expert opinion, and interpreting results for decision making. In addition to the framework, specific contributions were made in pavement and embankment hydrology and reactive transport, Bayesian statistics, and aqueous geochemistry of leaching. Contributions on water movement and reactive transport in highways included probabilistic prediction of leaching in an embankment, and scenario analyses of leaching and transport in pavements using HYDRUS2D, a contaminant fate and transport model. Water flow in a Minnesota highway embankment was replicated by Bayesian calibration of hydrological parameters against water content data. Extent of leaching of Cd from a coal fly ash was estimated. Two dimensional simulations of various scenarios showed that salts in the base layer of pavements are depleted within the first year whereas the metals may never reach the groundwater if the pavement is built on adsorbing soils. Aqueous concentrations immediately above the groundwater estimated for intact and damaged pavements can be used for regulators to determine the acceptability of various recycled materials. Contributions in the aqueous geochemistry of leaching included a new modeling approach for leaching of anions and cations from complex matrices such as weathered steel slag. The novelty of the method was its simultaneous inclusion of sorption and solubility controls for multiple analytes. The developed model showed that leaching of SO4, Cr, As, Si, Ca, Mg, and V were controlled by corresponding soluble solids. Leaching of Pb was controlled by Pb(VO4)3 solubility at low pHs and by surface precipitation reactions at high pHs. Leaching of Cd and Zn were controlled by surface complexation and surface precipitation, respectively

Predictive Model Development for Adsorption of Organic Contaminants by Carbon Nanotubes

The main objective of the study was to investigate mechanisms and statistical modeling of synthetic organic contaminant (SOC) adsorption by carbon nanotubes (CNTs). First, predictive models were developed for adsorption of low molecular weight aromatic compounds by multi-walled carbon nanotubes (MWCNTs) using experimental data for 59 compounds. Quantitative structure-activity relationship (QSAR) and linear solvation energy relationship (LSER) approaches were employed and developed models were externally validated using an independent dataset obtained from the literature. Up to date, no QSAR model has been reported for predicting adsorption of organics by CNTs. No LSER model is available which comprehensively investigates the adsorption of organics on CNTs. Only recently, one study reported an LSER equation for the modeling of their experimental adsorption data on one MWCNT. Then, adsorption of ten environmentally relevant halogenated aliphatic SOCs by a single walled (SWCNT) and MWCNT was tested experimentally for the first time in the literature. Several LSER models were developed to further examine the adsorption mechanisms. The LSER equations constitute the first predictive models generated for adsorption of aliphatic SOCs by CNTs. In addition, the poly-parameter LSER model was compared to those previously generated for adsorption of aromatic SOCs by CNTs. The LSER model generated in this research is currently the most comprehensive models available in the literature. Finally, the role of carbon nanotube morphology (i.e. surface area, diameter, and length) on the adsorption of phenanthrene (PNT) was investigated by analyzing the adsorption isotherms obtained with several SWCNTs and MCWNTs in the laboratory and the literature. The QSAR (r2 = 0.88), and LSER (r2 = 0.83) equations and their external validation accuracies indicated the success of parameter selection, data fitting ability, and the prediction strength of the developed models. These models were developed for adsorption of low-molecular weight (/mol) aromatic SOCs by MWCNTs (with less than 5% oxygen content) in distilled and deionized water. For aromatic SOC adsorption models, the molecular volume term (V) of the LSER model was the most influential descriptor controlling adsorption at all concentrations. At higher equilibrium concentrations, hydrogen bond donating (A) and hydrogen bond accepting (B) terms became significant in the models. For halogenated aliphatic SOC adsorption models, at higher concentrations, the B parameter, capturing hydrogen bond accepting ability, was the most influential descriptor both for SWCNT and MWCNT. The negative dependence on B indicates that as the hydrogen bond accepting ability of an aliphatic compound increases, it becomes less likely to be adsorbed by CNTs. The other important LSER parameters were V (size) followed by P (polarizability), and they were positively correlated with adsorption, indicating that size and polarizability favors adsorption. The contribution of these parameters was 2 - 3 times less than the B parameter. However, there was no single parameter predominant in the aliphatic SOC models. The number of data points for aliphatic SOCs were much smaller than aromatic models. These results indicated that adsorption of aromatic SOCs by CNTs strongly depend on adsorbate hydrophobicity; while for aliphatic SOCs, in addition to hydrophobic driving force, other interactions (i.e., hydrogen bond accepting ability) also play a role. Additional investigation of CNT properties on adsorption of PNT showed that at low (e.g., 1 μg/L) equilibrium concentrations, MWCNTs with the larger outer diameters exhibit higher adsorption capacity on a specific surface area basis than those with smaller diameters. With increasing equilibrium concentration, adsorption on a specific surface area basis becomes independent of MWCNT diameter, and maximum adsorption capacity was controlled by the total surface area. A similar analysis for the adsorption of naphthalene (NPT), a planar molecule with one less benzene ring but twenty times higher solubility than PNT, showed no correlation with respect to MWCNT outer diameter at both low and high equilibrium concentrations. The results indicated that the surface curvature of MWCNT was more important on the adsorption of PNT than on the adsorption of NPT due to its smaller molecular size and lower adsorption capacity than PNT. Specific surface area normalized isotherms did not show a correlation between PNT adsorption and lengths of SWCNTs and MWCNTs. Carbon nanotube characterization results showed that the morphology of CNTs impacts their aggregation and plays an important role on the available surface area and pore volume for adsorption. Manufacturer\u27s data may not always represent the characteristics of CNTs in a particular batch. Therefore, accurate characterization of CNTs is essential to systematically examine the behavior of CNTs (e.g., adsorption, transport) in environmental systems. A fundamental understanding of CNT-SOC adsorption interactions is important to (i) assess the environmental implications of CNT releases and spills to natural waters, and their roles as the contaminant carriers in the environment and, (ii) evaluate the potentials of CNTs as adsorbents in water and wastewater treatment applications. Predictive LSER modeling can be used to gain insight to the adsorption mechanisms by examining the individual contribution of intermolecular interactions to overall adsorption. This study examined and showed adsorption mechanisms and CNT properties (such as surface area, pore volume, outer diameter, and surface oxygen content) on the adsorption behavior of different classes of SOCs by CNTs

S7E4: How can we eliminate PFAS?

In recent years, communities across Maine and the U.S. have discovered the presence of toxic chemicals called per- and polyfluoroalkyl substances, or PFAS, in their land and water. Also known as forever chemicals because they are difficult to destroy, PFAS have been incorporated in various products, including food containers, clothing, rugs, teflon pans, fabrics and dental floss, for decades. Emerging research, however, has linked PFAS to several health issues, including weakened immune systems, increased risk of obesity and multiple cancers, developmental problems in children and harm to negative effects on reproduction. Onur Apul, assistant professor of environmental engineering at the University of Maine, is researching how to eliminate PFAS. He is one of many UMaine faculty members studying these forever chemicals and ways to mitigate them, and providing technical assistance to Maine farmers and other stakeholders. In Episode 4 of Season 7 of “The Maine Question,” Apul elaborates on the origins of PFAS, the threats they pose and efforts to stop their widespread contamination

Formulasi Limbah Kulit Ari Kopi Pembuatan Pelet Ikan

Penelitian ini bertujuan untuk memanfaatkan limbah kulit ari kopi sebagai bahan pembuatan pellet ikan dan mengetahui cara pembuatan pellet dari kulit ari kopi dan untuk mengetahui kandungan gizi yang terdapat pada kulit ari kopi. Penelitian ini dilaksanakan di Laboratorium Pengolahan Pangan Fakultas Pertanian Universitas Katolik Santo Thomas, Medan. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) faktorial.  Faktor  pertama adalah perbandingan tepung kulit ari dengan sandi (K) yang terdiri dari 6 taraf : K0 =100% tepung kulit ari kopi, K1 = 90% tepung kulit ari kopi, dengan 10% tepung jagung, K2 = 80% tepung kulit ari kopi, dengan 20% tepung jagung, K3 = 70% tepung kulit ari kopi, dengan 30% tepung jagung, K4 = 60% tepung kulit ari kopi, dengan 40% tepung jagung, K5 = 50% tepung kulit ari kopi, dengan 50% tepung jagung. Faktor kedua adalah lama penyimpanan dengan sandi (L) yang terdiri dari 6 taraf perlakuan yaitu : L0 = 0 minggu, L1= 2 minggu, L2=4 minggu, L3=6 minggu, L4=8 minggu dan L5=10 minggu. Hasil penelitian menunjukkan bahwa perlakuan perbandingan tepung kulit ari kopi dengan tepung kedelai berpengaruh sangat nyata (p<0,01) terhadap kadar air, kadar abu, pH dan daya apung, tetapi berpengaruh tidak nyata terhadap kadar protein, kadar lemak dan kadar abu pakan ikan. Perlakuan lama penyimpanan berpengaruh sangat nyata (p<0,01) terhadap terhadap kadar air, kadar abu, kadar protein, kadar serat, kadar lemak, pH dan daya apung pakan ikan. Interaksi perlakuan perbandingan tepung kulit ari kopi dengan tepung kedelai dan lama penyimpanan berpengaruh tidak nyata (p>0,01) terhadap kadar air, kadar abu, kadar protein, kadar serat, kadar lemak, pH pakan ikan dan daya apung pakan ikan

Bertarung Makna Ala Media ( Analisis Framing Pemberitaan Konflik Pasca Pemilihan Umum Kepala Daerah Kabupaten Sumba Barat Daya dalam Surat Kabar Harian Pos Kupang dan Harian Pagi Timor Express)

Penelitian ini mengungkap bagaimana dua surat kabar lokal di Nusa Tenggara Timur (NTT) yakni SKH Pos Kupang dan Harian Pagi Timor Express (Timex) membingkai konflik pasca pilkada di Kabupaten Sumba Barat Daya (SBD). Peneliti menggunakan metode analisis framing model Entman untuk melihat pembingkaian yang dilakukan dua media lokal ini dalam memberitakan konflik pilkada Kabupaten SBD. Hal ini berkaitan dengan bagaimana SKH Pos Kupang dan Timex menyeleksi isu, dan melakukan penonjolan aspek tertentu dari isu, yang terkait dengan konflik tersebut. Dengan analisis framing model Entman, peneliti menemukan dua frame besar yang mewakili SKH Pos Kupang dan Timex ketika membingkai peristiwa. Dua frame ini sejatinya memperlihatkan bagaimana peristiwa yang sama dilihat secara berbeda oleh dua media. SKH Pos Kupang yang cenderung melihat konflik sebagai bentuk dari kesengajaan KPU SBD sebagai lembaga resmi penyelenggara pemilu. Hal ini ditunjukkan dengan menonjolkan fakta penggelembungan suara. Sebaliknya Timex, membingkai konflik yang merupakan bentuk dari ketidakberdayaan KPU SBD sebagai penyelenggara pemilu. Ini ditunjukkan Timex dengan menonjolkan kelalaian KPU SBD yang hanya menempatkan dirinya sebagai ”tukang rekapitulasi”. Dua frame ini ditonjolkan SKH Pos Kupang dan Timex dengan menggunakan perangkat penalaran tertentu guna memperkuat basis pembenaran masing-masing

Pemanfaatan Minyak Sawit Dengan Limbah Lemak Sapi Menjadi Sabun Colek

Penelitian ini memanfaatkan minyak sawityang dicampur dengan limbah lemak sapi dalam pembuatan sabun colek, dan bertujuan untuk mengetahui perbandingan antara minyak sawit dan lemak sapi untuk menghasilkan sabun colek yang optimal. Penelitian ini dilaksanakan di Laboratorium Instrumentasi dan Kimia, Jurusan Teknologi Hasil Pertanian, Fakultas Pertanian Universitas Katolik Santo Thomas, Medan yang dilaksanakan pada bulan Pebruari 2022. Metoda penelitian ini bersifat analisa kuantitatif dengan menggunakan Model Rancangan Acak Lengkap (RAL) dengan perlakuan pencampuran Minyak Sawit dan Lemak Sapi  dengan perbandingan: Sabun A=100% Minyak Sawit, Sabun B=75% Minyak Sawit dengan 25% Lemak Sapi, Sabun C=50% Minyak Sawit dengan 50% Lemak Sapi, Sabun D=25% Minyak Sawit dengan 75% Lemak Sapi, Sabun E=100% Lemak Sapi. Hasil penelitian menunjukkan bahwa perbandingan Minyak Sawit Dengan Lemak Sapi berpengaruh nyata (p<0,05) terhadap Total Fatty Matter (TFM), pH sabun, dan tekstur sabun dan berpengaruh tidak nyata (p>0.05) terhadap kadar air dan tinggi busa sabun. Mutu sabun terbaik diperoleh pada perbandingan 25% Minyak Sawit dengan 75% Lemak Sapi

Determinasi formula sari biji nangka (Arthocarpus heterophyllus) dan sari buah stroberi (Fragria ananassa) pada pengolahan susu Nangstro

Penelitian ini bertujuan untuk memperoleh formula sari biji buah nangka dan sari buah stroberi pada pengolahan susu Nangstro. Penelitian ini terdiri dari dua tahapan penelitian terpisah yang masing-masing dilakukan dengan dengan menggunakan Rancangan Acak Lengkap. Penelitian tahap pertama adalah menentukan formula biji nangka (SBN) dan sari buah stroberi (SBS) dengan perlakuan SBN 80%, SBS 20%; SBN 70%, SBS 30%; SBN 60%, SBS 40%; dan SBN 50%, SBS 50%. Penelitian tahap kedua menentukan umur simpan susu Nangstro dengan perlakuan 0, 3, 6 dan 9 hari. Hasil penelitian menunjukkan bahwa susu Nangstro dengan formula SBN 80% dan SBS 20% dapat diterima oleh panelis. Semakin tinggi kadar SBS dalam formula susu Nangstro akan menurunkan kadar protein, kadar kalsium, total padatan terlarut, dan penerimaan sensorisnya. Kadar SBS yang tinggi akan meningkatkan total asam susu Nangstro. Selama penyimpanan, susu Nangstro mengalami penurunan kadar protein, kalsium dan total padatan terlarut, dilain pihak total asamnya semakin meningkat

Probabilistic modeling of one dimensional water movement and leaching from highway embankments containing secondary materials

Predictive methods for contaminant release from virgin and secondary road construction materials are important for evaluating potential long-term soil and groundwater contamination from highways. The objective of this research was to describe the field hydrology in a highway embankment and to investigate leaching under unsaturated conditions by use of a contaminant fate and transport model. The HYDRUS2D code was used to solve the Richards equation and the advection–dispersion equation with retardation. Water flow in a Minnesota highway embankment was successfully modeled in one dimension for several rain events after Bayesian calibration of the hydraulic parameters against water content data at a point 0.32 m from the surface of the embankment. The hypothetical leaching of Cadmium from coal fly ash was probabilistically simulated in a scenario where the top 0.50 m of the embankment was replaced by coal fly ash. Simulation results were compared to the percolation equation method where the solubility is multiplied by the liquid-to-solid ratio to estimate total release. If a low solubility value is used for Cadmium, the release estimates obtained using the percolation/equilibrium model are close to those predicted from HYDRUS2D simulations (10–4–10–2 mg Cd/kg ash). If high solubility is used, the percolation equation over predicts the actual release (0.1–1.0 mg Cd/kg ash). At the 90th percentile of uncertainty, the 10-year liquid-to-solid ratio for the coal fly ash embankment was 9.48 L/kg, and the fraction of precipitation that infiltrated the coal fly ash embankment was 92%. Probabilistic modeling with HYDRUS2D appears to be a promising realistic approach to predicting field hydrology and subsequent leaching in embankments

Peranan umpasa dalam masyarakat Batak Toba

Naskah laporan penelitian yang telah dinilai dan di suntillg di t e rbilkan ekarang agar dapal dimanfaatkan oleh para ahli dan anggo ta masyarakat luas . Naskah yang berjudul "Pcranan Umpasa dalam Masyarakat Batak Toba" disusun oleh regu peneliti yang lerdiri alas anggota-anggola: Apul Simbolan. Bislok Sirait, dan Mangasa Silitonga yang melldapat banluan Proyek Peneli­ tian Bahasa dan Sastra Indonesia dan Daerah-Sumatra Utara tailun 1981/1982. Naskah itu disunting oleh Ora. Hartini Supadi dari Pusal Pembinaan dan Pengembangan Bahasa

Pemanfaatan Kulit Pisang Raja Sebagai Bahan Pembuatan Pelet

Penelitian ini bertujuan untuk memanfaatkan limbah kulit pisang Raja sebagai bahan pembuatan pellet dan mengetahui bagaimana cara pembuatan pellet kulit pisang raja dan untuk mengetahui kandungan gizi yang terdapat pada kulit pisang Raja. Penelitian ini dilaksanakan di Laboratorium Pengolahan Pangan Fakultas Pertanian Universitas Katolik Santo Thomas, Medan. Rancangan yang digunakan dalam penelitian ini adalah Rancangan Acak Lengkap (RAL) dalam bentuk faktorial. Faktor pertama adalah persentase tepung kulit pisang Raja dengan tepung kedelai dengan sandi K terdiri dari : K0 = 100% tepung Kulit Pisang Raja, K1 =  90% tepung Kulit Pisang Raja, dengan 10% tepung kedelai, K2 =  80% tepung Kulit Pisang Raja, dengan 20% tepung kedelai, K3  =  70% tepung Kulit Pisang Raja, dengan 30% tepung kedelai, K4  = 60% tepung Kulit Pisang Raja, dengan 40% tepung kedelai dan K5v = 50% tepung Kulit Pisang Raja, dengan 50% tepung kedelai. Faktor kedua adalah lama penyimpanan 6 taraf perlakuan dengan sandi L terdiri dari : L0 = 0 minggu, L1 = 2 minggu, L2 =  4 minggu, L3 =  6 minggu, L4 =  8 minggu dan L5 = 10 minggu. Analisis data menggunakan analisis sidik ragam. Hasil penelitian menunjukkan bahwa perlakuan perbandingan kulit pisang raja dengan tepung kedelai sangat nyata (p<0,01) terhadap kadar protein, kadar lemak, kadar serat dan pH, berpengaruh nyata (p<0,05) terhadap kadar air, serta berpengaruh tidak nyata (p>0,05) terhadap kadar abu pellet. Penggunaan tepung kedelai yang semakin tinggi maka kadar air, kadar protein, kadar lemak dan pH pellet semakin meningkat, sedangkan kadar abu dan kadar serat kasar pellet semakin menurun. Perlakuan lama penyimpanan berpengaruh sangat nyata (p<0,01) terhadap kadar air, kadar abu, kadar protein, kadar lemak, kadar serat kasar dan pH pellet.  Semakin lama penyimpanan maka kadar air pellet semakin meningkat, sedangkan kadar abu, kadar protein, kadar serat kasar, kadar lemak dan pH semakin menurun. Interaksi perlakuan perbandingan kulit pisang raja dengan tepung kedelai dan lama penyimpanan berpengaruh sangat nyata (p<0,01) terhadap pH, tetapi berpengaruh tidak nyata terhadap kadar air, kadar abu, kadar protein, kadar lemak dan kadar serat kasar pellet. Mutu pellet terbaik diperoleh pada kombinasi perlakuan K5L0. &nbsp