This page has only limited features, please log in for full access.

Dr. Raju Khatiwada
Compass Minerals

Basic Info

Basic Info is private.

Research Keywords & Expertise

0 Agronomy
0 Analytical Chemistry
0 Environmental Chemistry
0 Fertilizers
0 Soil Science,

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

The user biography is not available.
Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Journal article
Published: 13 February 2021 in Agriculture
Reads 0
Downloads 0

This research focuses on the efficiency of recommended heavy use area protection (HUAP) pads installed in poultry houses utilizing the Choptank River, a tributary of the Chesapeake Bay. The Chesapeake Bay watershed is severely affected by crop agriculture and poultry feeding operations. Water quality degradation along with scarcity of water is a significant concern in this area, suggesting a need for changes in both environmental and groundwater management practices. Our objective in this study was to compare the efficiency of HUAP in reducing litter spillage and nutrient runoff between two poultry houses, one of which was constructed in 2005 and the other in 2009. The poultry house constructed in 2005 did not have HUAP pads initially; they were built in 2006. The poultry house built in 2009 had the pads from the starting point. We collected soil and water samples each month and analyzed them for pH, electrical conductivity (EC), nitrate, nitrite, total nitrogen, phosphate, and other soil properties throughout the year. The pH of soil and water samples was in the range of 6.8–8.0 and 6.5–7.2, respectively. We collected six water samples in total in the ditch, from points at retention ponds near the farm ditch to sites in wooded areas on the farm. Water sample B (where ditch water meets retention pond water from the poultry farm) had the highest EC value and nitrate, nitrite, and total nitrogen concentrations compared with other water samples. The subsequent water samples downstream had reduced loads of nutrients. The study results suggest that there was a minimum carryover of nutrients from soil into the runoff water, storm ditches, and adjacent stream. There was also a minimal effect of house cleaning and storm events in raising the concentration of nutrients in soil and water samples at our study sites. The older poultry site had higher total nitrogen and phosphorous surrounding the pads, whereas no elevated levels of nutrients were identified at the newer site. The ability of HUAP pads to hold onto contaminates decreases with age and use. This study also shows that the impacts from poultry activities on surface and groundwater can be minimized by using management practices such as HUAP pads. These practices can reduce pollution in the farm, increase productivity, and save farmers and ranchers time and money in the long run.

ACS Style

Gulnihal Ozbay; Raju Khatiwada; Stacy Smith; Lathadevi Chintapenta. Efficacy of Heavy Use Area Protection (HUAP) Pads in Poultry Farm. Agriculture 2021, 11, 154 .

AMA Style

Gulnihal Ozbay, Raju Khatiwada, Stacy Smith, Lathadevi Chintapenta. Efficacy of Heavy Use Area Protection (HUAP) Pads in Poultry Farm. Agriculture. 2021; 11 (2):154.

Chicago/Turabian Style

Gulnihal Ozbay; Raju Khatiwada; Stacy Smith; Lathadevi Chintapenta. 2021. "Efficacy of Heavy Use Area Protection (HUAP) Pads in Poultry Farm." Agriculture 11, no. 2: 154.

Research article
Published: 13 January 2020 in PLOS ONE
Reads 0
Downloads 0

Particle size is one factor affecting phosphorus (P) dynamics in soils and sediments. This study investigated how flow facilitated by hydraulic pumps and aquatic vegetation species water lettuce (Pistia stratiotes) and water hyacinth (Eichhornia crassipes) affected particle size and P-dynamics in organic sediments in agricultural drainage ditches. Sediments with finer particle size (>0.002 mm) were hypothesized to contain greater total P (TP) and less labile P than sediments with coarser particle size. Particle size was determined using a LS 13 320 Laser Diffraction Particle Size Analyzer. Sediments were tested for pH, TP, and organic matter. Fractions of P were determined using a sequential fractionation experiment and 31P Nuclear Magnetic Resonance (NMR) Spectroscopy. Larger average particle size and lower average total P concentrations were found in the inflows of the field ditches compared to the outflows. Presence of flow and aquatic vegetation did not have a significant impact on particle size, TP, or labile P fractions. Median (p = 0.10) particle size was not significantly correlated to TP. Overall, there was an average trend of coarser particle size and lower P concentrations in the inflow compared to the outflow. The presence of inorganic limerock could have affected results due to increased P adsorption capacity and larger average particle size compared to the organic fraction of the sediment.

ACS Style

Jay Capasso; Jehangir H. Bhadha; Allan Bacon; Lilit Vardanyan; Raju Khatiwada; Julio Pachon; Mark Clark; Timothy Lang. Influence of flow on phosphorus-dynamics and particle size in agricultural drainage ditch sediments. PLOS ONE 2020, 15, e0227489 .

AMA Style

Jay Capasso, Jehangir H. Bhadha, Allan Bacon, Lilit Vardanyan, Raju Khatiwada, Julio Pachon, Mark Clark, Timothy Lang. Influence of flow on phosphorus-dynamics and particle size in agricultural drainage ditch sediments. PLOS ONE. 2020; 15 (1):e0227489.

Chicago/Turabian Style

Jay Capasso; Jehangir H. Bhadha; Allan Bacon; Lilit Vardanyan; Raju Khatiwada; Julio Pachon; Mark Clark; Timothy Lang. 2020. "Influence of flow on phosphorus-dynamics and particle size in agricultural drainage ditch sediments." PLOS ONE 15, no. 1: e0227489.

Journal article
Published: 01 September 2018 in Environmental Pollution
Reads 0
Downloads 0

The emerging insensitive munitions compound (IMC) 3-nitro-1,2,4-triazole-5-one (NTO) is currently being used to replace conventional explosives such as 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), but the environmental fate of this increasingly widespread IMC remains poorly understood. Upon release from unexploded solid phase ordinances, NTO exhibits high aqueous solubility and, hence, potential mobilization to groundwater. Adsorption and abiotic transformation at metal oxide surfaces are possible mechanisms for natural attenuation. Here, the reactions at ferrihydrite and birnessite surfaces of NTO and its biotransformation product, 3-amino-1, 2, 4-triazol-5-one (ATO), were studied in stirred batch reactor systems at controlled pH (7.0). The study was carried out at metal oxide solid to solution ratios (SSR) of 0.15, 1.5 and 15 g kg−1. The samples were collected at various time intervals up to 3 h after reaction initiation, and analyzed using HPLC with photodiode array and mass spectrometric detection. We found no detectable adsorption or transformation of NTO upon reaction with birnessite, whereas ATO was highly susceptible to oxidation by the same mineral, showing nearly complete transformation within 5 min at 15 g kg−1 SSR to urea, CO2(g) and N2(g). The mean surface-area-normalized pseudo-first order rate constant (k) for ATO oxidation by birnessite across all SSRs was 0.05 ± 0.022 h−1 m−2, and oxidation kinetics were independent of dissolved O2 concentration. Both NTO and ATO were resistant to oxidation by ferrihydrite. However, NTO showed partial removal from solution upon reaction with ferrihydrite at 0.15 and 1.5 g kg−1 SSR and complete loss at 15 g kg−1 SSR due to strong adsorption. Conversely, ATO adsorption to ferrihydrite was much weaker than that measured for NTO.

ACS Style

Raju Khatiwada; Leif Abrell; Guangbin Li; Robert A. Root; Reyes Sierra-Alvarez; James A. Field; Jon Chorover. Adsorption and oxidation of 3-nitro-1,2,4-triazole-5-one (NTO) and its transformation product (3-amino-1,2,4-triazole-5-one, ATO) at ferrihydrite and birnessite surfaces. Environmental Pollution 2018, 240, 200 -208.

AMA Style

Raju Khatiwada, Leif Abrell, Guangbin Li, Robert A. Root, Reyes Sierra-Alvarez, James A. Field, Jon Chorover. Adsorption and oxidation of 3-nitro-1,2,4-triazole-5-one (NTO) and its transformation product (3-amino-1,2,4-triazole-5-one, ATO) at ferrihydrite and birnessite surfaces. Environmental Pollution. 2018; 240 ():200-208.

Chicago/Turabian Style

Raju Khatiwada; Leif Abrell; Guangbin Li; Robert A. Root; Reyes Sierra-Alvarez; James A. Field; Jon Chorover. 2018. "Adsorption and oxidation of 3-nitro-1,2,4-triazole-5-one (NTO) and its transformation product (3-amino-1,2,4-triazole-5-one, ATO) at ferrihydrite and birnessite surfaces." Environmental Pollution 240, no. : 200-208.

Journal article
Published: 01 June 2018 in Chemosphere
Reads 0
Downloads 0

Abiotic transformation of anthropogenic compounds by redox-active metal oxides affects contaminant fate in soil. The capacity of birnessite and ferrihydrite to oxidize the insensitive munitions compound, 2,4-dinitroanisol (DNAN), and its amine-containing daughter products, 2-methoxy-5-nitro aniline (MENA) and 2,4-diaminoanisole (DAAN), was studied in stirred reactors at controlled pH (7.0). Aqueous suspensions were reacted at metal oxide solid to solution mass ratios (SSR) of 0.15, 1.5 and 15 g kg and solutions were analyzed after 0-3 h by high performance liquid chromatography coupled with photodiode array or mass spectrometry detection. Results indicate that DNAN was resistant to oxidation by birnessite and ferrihydrite. Ferrihydrite did not oxidize MENA, but MENA was susceptible to rapid oxidation by birnessite, with nitrogen largely mineralized to nitrite. This is the first report on mineralization of nonphenolic aromatics and the release of mineralized N from aromatic amines following reaction with birnessite. DAAN was oxidized by both solids, but ca. ten times higher rate was observed with birnessite as compared to ferrihydrite at an SSR of 1.5 g kg. At 15 g kg SSR, DAAN was removed from solution within 5 min of reaction with birnessite. CO evolution experiments indicate mineralization of 15 and 12% of the carbon associated with MENA and DAAN, respectively, under oxic conditions with birnessite at SSR of 15 g kg. The results taken as a whole indicate that initial reductive (bio)transformation products of DNAN are readily oxidized by birnessite. The oxidizability of the reduced DNAN products was increased with progressive (bio)reduction as reflected by impacts on the oxidation rate.

ACS Style

Raju Khatiwada; Christopher Olivares; Leif Abrell; Robert A. Root; Reyes Sierra-Alvarez; James A. Field; Jon Chorover. Oxidation of reduced daughter products from 2,4-dinitroanisole (DNAN) by Mn(IV) and Fe(III) oxides. Chemosphere 2018, 201, 790 -798.

AMA Style

Raju Khatiwada, Christopher Olivares, Leif Abrell, Robert A. Root, Reyes Sierra-Alvarez, James A. Field, Jon Chorover. Oxidation of reduced daughter products from 2,4-dinitroanisole (DNAN) by Mn(IV) and Fe(III) oxides. Chemosphere. 2018; 201 ():790-798.

Chicago/Turabian Style

Raju Khatiwada; Christopher Olivares; Leif Abrell; Robert A. Root; Reyes Sierra-Alvarez; James A. Field; Jon Chorover. 2018. "Oxidation of reduced daughter products from 2,4-dinitroanisole (DNAN) by Mn(IV) and Fe(III) oxides." Chemosphere 201, no. : 790-798.

Research article
Published: 01 January 2018 in Environmental Chemistry
Reads 0
Downloads 0

Environmental contextThere is a growing need to understand how insensitive munitions compounds behave in natural environments, particularly in soils, where non-combusted residues accumulate. Here, we tested the ability of sulfate green rust, a naturally occurring mineral, to transform munitions compounds by reacting with the mineral surface. Our results show that both the munitions compounds and the mineral structures are transformed in an oxidation–reduction reaction that alters the compounds’ environmental fates. AbstractAbiotic transformation of contaminants by redox-active mineral surfaces plays an important role in the fate and behaviour of pollutants in soils and sediments. However, there is very little information on such transformations for the insensitive munitions compounds (IMCs), 3-nitro-1,2,4-triazol-5-one (NTO) and 2,4-dinitroanisole (DNAN), developed in recent years to replace the traditional munition compounds in explosive mixtures. We tested the ability of sulfate green rust to transform NTO and DNAN (0.5 mM) under anoxic conditions at pH 8.4 in laboratory experiments, by using green rust supplied at 10 g kg−1 (w/w) solid concentration. Results indicate that NTO and DNAN underwent rapid abiotic reduction to their organic amine daughter products. NTO was completely transformed to 5-amino-1,2 4-triazol-3-one (ATO) within 20 min of reaction. This is the first report of NTO reduction by a naturally occurring mineral. Similarly, DNAN was rapidly transformed to 2-methoxy-5-nitroaniline (MENA) and 4-methoxy-5-nitroaniline (iMENA). The reduction occurred with an intriguing staggered regioselectivity. Over the first 10 min, the para-nitro group of DNAN was selectively reduced to generate iMENA. Thereafter, the ortho-nitro group was preferentially reduced, generating MENA. Both iMENA and MENA were subsequently transformed to the final reduction product 2,4-diaminoanisol (DAAN) within 1 day. Iron Kα X-ray absorption near-edge spectroscopy (XANES) studies of reacted solids indicated oxidative transformation of the green rust to lepidocrocite-like mineral forms. These results indicate that the IMCs can be rapidly transformed in soil, sediment or aquatic environments containing green rust.

ACS Style

Raju Khatiwada; Robert A. Root; Leif Abrell; Reyes Sierra-Alvarez; James A. Field; Jon Chorover. Abiotic reduction of insensitive munition compounds by sulfate green rust. Environmental Chemistry 2018, 15, 259 .

AMA Style

Raju Khatiwada, Robert A. Root, Leif Abrell, Reyes Sierra-Alvarez, James A. Field, Jon Chorover. Abiotic reduction of insensitive munition compounds by sulfate green rust. Environmental Chemistry. 2018; 15 (5):259.

Chicago/Turabian Style

Raju Khatiwada; Robert A. Root; Leif Abrell; Reyes Sierra-Alvarez; James A. Field; Jon Chorover. 2018. "Abiotic reduction of insensitive munition compounds by sulfate green rust." Environmental Chemistry 15, no. 5: 259.

Journal article
Published: 28 July 2017 in Sustainable Agriculture Research
Reads 0
Downloads 0

The application of agrichar derived from organic feedstocks has the potential to improve soil fertility and crop production by providing major nutrients like phosphorus (P) to the crop, and in some cases also reducing P leaching. The effect of agrichar on the leaching of P in soils is not uniform and can vary depending on the type of agrichar and amount applied. The objective of this study was to (i) evaluate the behavior of four agrichars (rice hulls RH, palm fronds PF, horse bedding HB, and bagasse BG) for their ability to retain/release P and (ii) determine the effect of wet sonication on P sorption behavior. The feedstocks were torrefied at 500 °C using a top-lit updraft gasifier and used in multiple batch incubation experiments to evaluate equilibrium phosphorus concentration, maximum P sorption capacity (Smax), and adsorption/desorption potential. Both, RH (12.6 g kg-1) and HB (11.5 g kg-1) contained 10-15 times higher total P concentration than PF and BG, rendering RH and HB as potentially suitable products to be used as soil amendments. However, this initial P content of the agrichar seemed to have an overriding effect on the P sorption behavior of the agrichar. PF had Smax of 676 (±127) mg kg-1 for the non-sonicated agrichar, and 237 (±91) mg kg-1 following sonication. There was significant increase in CEC for PF and BG agrichar upon sonication. PF agrichar increased from 27 (±3) cmolc kg-1 to 41 (±4) cmolc kg-1 with sonication. Similarly, BG agrichar CEC increased from 21 (±2) cmolc kg-1 to 45 (±5) cmolc kg-1 with sonication. Initial total P and Ca concentration and their ratios was found to play significant roles on P adsorption and desorption. Major cations like Ca, Fe, Al and Mn are found to act as active sorption site for phosphorus controlling its fate and mobility along with compounding effects of other physicochemical parameters.

ACS Style

Jehangir Bhadha; Stephen P. Jennewein; Raju Khatiwada. Phosphorus Sorption Behavior of Torrefied Agricultural Byproducts under Sonicated Versus Non-Sonicated Conditions. Sustainable Agriculture Research 2017, 6, 1 .

AMA Style

Jehangir Bhadha, Stephen P. Jennewein, Raju Khatiwada. Phosphorus Sorption Behavior of Torrefied Agricultural Byproducts under Sonicated Versus Non-Sonicated Conditions. Sustainable Agriculture Research. 2017; 6 (4):1.

Chicago/Turabian Style

Jehangir Bhadha; Stephen P. Jennewein; Raju Khatiwada. 2017. "Phosphorus Sorption Behavior of Torrefied Agricultural Byproducts under Sonicated Versus Non-Sonicated Conditions." Sustainable Agriculture Research 6, no. 4: 1.

Journal article
Published: 15 April 2015 in Environmental Science & Technology
Reads 0
Downloads 0

Insensitive munitions (IM) are a new class of explosives that are increasingly being adopted by the military. The ability of soil microbial communities to degrade IMs is relatively unknown. In this study, microbial communities from a wide range of soils were tested in microcosms for their ability to degrade the IM, 3-nitro-1,2,4-triazol-5-one (NTO). All seven soil inocula tested were able to readily reduce NTO to 3-amino-1,2,4-triazol-5-one (ATO) via 3-hydroxyamino-1,2,4-triazol-5-one (HTO), under anaerobic conditions with H2 as an electron donor. Numerous other electron donors were shown to be suitable for NTO-reducing bacteria. The addition of a small amount of yeast extract (10 mg/L) was critical to diminish lag times and increased the biotransformation rate of NTO in nearly all cases indicating yeast extract provided important nutrients for NTO-reducing bacteria. The main biotransformation product, ATO, was degradable only in aerobic conditions, as evidenced by a rise in the inorganic nitrogen species nitrite and nitrate, indicative of nitrogen-mineralization. NTO was nonbiodegradable in aerobic microcosms with all soil inocula.

ACS Style

Mark Krzmarzick; Raju Khatiwada; Christopher Olivares; Leif Abrell; Reyes Sierra-Alvarez; Jon Chorover; James A. Field. Biotransformation and Degradation of the Insensitive Munitions Compound, 3-Nitro-1,2,4-triazol-5-one, by Soil Bacterial Communities. Environmental Science & Technology 2015, 49, 5681 -5688.

AMA Style

Mark Krzmarzick, Raju Khatiwada, Christopher Olivares, Leif Abrell, Reyes Sierra-Alvarez, Jon Chorover, James A. Field. Biotransformation and Degradation of the Insensitive Munitions Compound, 3-Nitro-1,2,4-triazol-5-one, by Soil Bacterial Communities. Environmental Science & Technology. 2015; 49 (9):5681-5688.

Chicago/Turabian Style

Mark Krzmarzick; Raju Khatiwada; Christopher Olivares; Leif Abrell; Reyes Sierra-Alvarez; Jon Chorover; James A. Field. 2015. "Biotransformation and Degradation of the Insensitive Munitions Compound, 3-Nitro-1,2,4-triazol-5-one, by Soil Bacterial Communities." Environmental Science & Technology 49, no. 9: 5681-5688.

Research front
Published: 01 January 2015 in Environmental Chemistry
Reads 0
Downloads 0

Environmental context Insensitive munitions compounds are increasingly used in the manufacture of military energetic materials because of their lower unintentional explosion risk during transport and handling. The current study was designed to better resolve the environmental chemistry of two of these insensitive munitions compounds. In particular, we investigated the solid–solution partitioning that occurs when aqueous solutions containing dissolved unexploded ordinances come into contact with soil mineral media. Abstract Insensitive munitions compounds (IMCs) are increasingly used for military energetic materials, yet their environmental fate is poorly understood. Prior work has shown that the nitroaromatic 2,4-dinitroanisole (DNAN) and the heterocyclic nitrogen compound 3-nitro-1,2,4-triazole-5-one (NTO), both newly introduced IMCs, can undergo microbially mediated reduction under anoxic conditions to form 2-methoxy-5-nitroaniline (MENA) and 3-amino-1,2,4,triazole-5-one (ATO) respectively. In the present work, DNAN, MENA, NTO and ATO were subjected to batch adsorption–desorption experiments with specimen soil mineral adsorbents that included montmorillonite, birnessite and goethite. DNAN and MENA exhibited high affinity, linear adsorption to montmorillonite, with enhanced surface excess at a given aqueous equilibrium concentration for K+-saturated relative to Na+-saturated forms, but negligible adsorption to the metal oxides. Powder X-ray diffraction data and surface occupancy calculations indicate interlayer intrusion by DNAN and MENA and adsorption at siloxane sites. Conversely, NTO and ATO exhibited low sorptive affinity and apparent anion exclusion upon reaction with the negatively charged layer silicate clays. However, both of the N-heterocycles showed positive adsorption affinities for goethite (Kd values of 11.1 and 3.1, and HI values of 1.8 and 0.50 respectively), consistent with anion adsorption to the positively charged goethite surface. Both ATO and MENA were subjected to apparent oxidative, abiotic chemical transformation during reaction with birnessite. The results indicate that the IMCs studied will exhibit adsorptive retardation – and their biodegradation products may undergo further abiotic transformation – upon reaction at soil mineral surfaces.

ACS Style

Billy R. Linker; Raju Khatiwada; Nico Perdrial; Leif Abrell; Reyes Sierra-Alvarez; James A. Field; Jon Chorover. Adsorption of novel insensitive munitions compounds at clay mineral and metal oxide surfaces. Environmental Chemistry 2015, 12, 74 -84.

AMA Style

Billy R. Linker, Raju Khatiwada, Nico Perdrial, Leif Abrell, Reyes Sierra-Alvarez, James A. Field, Jon Chorover. Adsorption of novel insensitive munitions compounds at clay mineral and metal oxide surfaces. Environmental Chemistry. 2015; 12 (1):74-84.

Chicago/Turabian Style

Billy R. Linker; Raju Khatiwada; Nico Perdrial; Leif Abrell; Reyes Sierra-Alvarez; James A. Field; Jon Chorover. 2015. "Adsorption of novel insensitive munitions compounds at clay mineral and metal oxide surfaces." Environmental Chemistry 12, no. 1: 74-84.

Journal article
Published: 09 November 2012 in Soil Science Society of America Journal
Reads 0
Downloads 0

Phosphorus management in reduced‐tillage systems is a great concern for farmers. Conclusive positive results of deep‐banding P fertilizers compared with broadcast application and the chemistry of reduced‐tillage systems remain unclear. Knowledge of the dominant solid P species present in soil following application of P fertilizers and the resulting potential P availability would help us understand and efficiently manage P in reduced‐tillage systems. The objective of this research was to study the influence of placement (broadcast vs. deep‐band P), fertilizer source (granular vs. liquid P), and time on the reaction products of P under field conditions. Changes in soil pH, resin‐extractable P, total P, and speciation of P were determined at different distances from the point of fertilizer application at 5 wk and 6 mo after P application at a rate of 75 kg ha−1 to a soil system that was under long‐term reduced tillage. Resin‐extractable P was lower for broadcast treatments compared with deep‐band treatments for both time periods. Resin‐extractable P was greater in the liquid P‐treated soils than in the granular P‐treated soils. Speciation results showed that granular P fertilizers tended to form Fe–P‐like forms, whereas liquid forms remained in adsorbed P‐like forms in the soil 5 wk after application; moreover, speciation results showed granular P fertilizers precipitated less when deep‐banded. During the 6‐mo period following application, reaction products of broadcast granular, broadcast liquid, and deep‐band granular fertilizers transformed to Ca‐phosphate or mixtures of Ca‐, Fe‐ and adsorbed‐phosphate‐like forms, whereas deep‐band liquid P remained as mainly adsorbed P‐like forms. Deep‐banding of P would most likely provide a solution that is both agronomically and environmentally efficient for reduced‐till farmers.

ACS Style

Raju Khatiwada; Ganga M. Hettiarachchi; David B. Mengel; Mingwei Fei. Speciation of Phosphorus in a Fertilized, Reduced-Till Soil System: In-Field Treatment Incubation Study. Soil Science Society of America Journal 2012, 76, 2006 -2018.

AMA Style

Raju Khatiwada, Ganga M. Hettiarachchi, David B. Mengel, Mingwei Fei. Speciation of Phosphorus in a Fertilized, Reduced-Till Soil System: In-Field Treatment Incubation Study. Soil Science Society of America Journal. 2012; 76 (6):2006-2018.

Chicago/Turabian Style

Raju Khatiwada; Ganga M. Hettiarachchi; David B. Mengel; Mingwei Fei. 2012. "Speciation of Phosphorus in a Fertilized, Reduced-Till Soil System: In-Field Treatment Incubation Study." Soil Science Society of America Journal 76, no. 6: 2006-2018.