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West Fargo, ND, United States

Simsek H.,North Dakota State University | Kasi M.,North Dakota State University | Kasi M.,Moore Engineering Inc. | Wadhawan T.,North Dakota State University | And 3 more authors.
Water Research | Year: 2012

Dissolved organic nitrogen (DON) represents a significant portion of nitrogen in the final effluent of wastewater treatment plants (WWTPs). Biodegradable portion of DON (BDON) can support algal growth and/or consume dissolved oxygen in the receiving waters. The fate of DON and BDON has not been studied for trickling filter WWTPs. DON and BDON data were collected along the treatment train of a WWTP with a two-stage trickling filter process. DON concentrations in the influent and effluent were 27% and 14% of total dissolved nitrogen (TDN). The plant removed about 62% and 72% of the influent DON and BDON mainly by the trickling filters. The final effluent BDON values averaged 1.8 mg/L. BDON was found to be between 51% and 69% of the DON in raw wastewater and after various treatment units. The fate of DON and BDON through the two-stage trickling filter treatment plant was modeled. The BioWin v3.1 model was successfully applied to simulate ammonia, nitrite, nitrate, TDN, DON and BDON concentrations along the treatment train. The maximum growth rates for ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria, and AOB half saturation constant influenced ammonia and nitrate output results. Hydrolysis and ammonification rates influenced all of the nitrogen species in the model output, including BDON. © 2012 Elsevier Ltd. Source

Lim Y.H.,University of North Dakota | Hafliger K.,Moore Engineering Inc.
World Environmental and Water Resources Congress 2013: Showcasing the Future - Proceedings of the 2013 Congress | Year: 2013

Several statistical techniques for detecting changes in river flooding patterns have been applied to the peak annual flow series of 101 USGS stations found in the Upper Midwest and the implications on flood frequency statistics based on splitting the systematic flood records are then examined. Mann-Kendall trend test is one of the techniques used to determine if an increasing trend exists overall in the entire annual peak flows series up to the latest year in the record. For each station that exhibits a trend, moving average and ratio of means methods are performed on the series in preparation for a two-tailed t-test, which pinpoints a trend change year. The flood frequency statistics of the stations are updated using the trend change year found. To study the flooding trends more closely, wavelet analysis is used to detect trend changes in the daily flow series. Wavelet coefficient plots are made at several cycle lengths allowing the determination of trend changes occurring at each scale. The research shows varying effectiveness of the techniques used in detecting trend. Through wavelet analysis, the influence of ENSO may be shown as a possible cause of trend change although the splitting of a series may be necessary as indicated by the statistical techniques. © 2013 American Society of Civil Engineers. Source

Harrington D.J.,Moore Engineering Inc.
Structures Congress 2010 | Year: 2010

A sea change has occurred over the past couple of years in the way that design firms document and deliver building designs. The era of 2D CAD drafting is slowly giving way to Building Information Modeling, or BIM. BIM provides for the complete 3-dimensional representation of building project data in a single file, database format. From this file, almost any information contained in the database can be extracted and presented in any documentation format. This conversion from 2D drafting to 3D BIM is dramatically changing the production process, and the firms that make this change are finding that they need to develop a whole new set of standards for this new process. This paper presents the process and results of implementing a new set of standards at a structural engineering firm that has converted to the BIM process. Standards regarding documentation, workflow, information exchange, project coordination, and conceptual design will be covered. © 2010 American Society of Civil Engineers. Source

Simsek H.,North Dakota State University | Kasi M.,Moore Engineering Inc. | Ohm J.-B.,U.S. Department of Agriculture | Blonigen M.,City of Fargo Wastewater Treatment Plant | Khan E.,North Dakota State University
Water Research | Year: 2013

A study was carried out to understand the fate of biodegradable dissolved organic nitrogen (BDON) and bioavailable dissolved organic nitrogen (ABDON) along the treatment trains of a wastewater treatment facility (WWTF) equipped with an activated sludge (AS) system and a WWTF equipped with a two-stage trickling filter (TF) process. A mixed culture bacterial inoculum was used for BDON determination, while a pure cultured algal inoculum (Selenastrum capricornutum) and a combination of the bacterial and alga inocula were used for ABDON determination. Results show that BDON and ABDON varied significantly within the treatment facility and between the two facilities. From after primary clarification to final effluent, the TF facility removed 65% of BDON and 63% of ABDON while the AS facility removed 68% of BDON and 56% of ABDON. For the TF facility, BDON and ABDON were 62% and 71% of the effluent dissolved organic nitrogen (DON), while they were 26% and 47% of the effluent DON for the AS WWTF. BDON and ABDON results, which are based on incubation of samples under different inocula (bacteria only, algae only, and bacteria+algae), further showed that some portions of DON are utilizable by bacteria only or algae only while there is a portion of DON utilizable by either bacteria or algae. DON utilization was the highest when both bacteria and algae were used as a co-inoculum in the samples. This study is the first to investigate the fate of BDON and ABDON along the treatment trains of two different WWTFs. © 2013 Elsevier Ltd. Source

Kasi M.,North Dakota State University | Kasi M.,Moore Engineering Inc. | Wadhawan T.,North Dakota State University | McEvoy J.,North Dakota State University | And 2 more authors.
Biodegradation | Year: 2013

A comprehensive study on the effects of different carbon sources during the bacterial enrichment on the removal performances of benzene, toluene, ethylbenzene, and xylenes (BTEX) compounds when present as a mixture was conducted. Batch BTEX removal kinetic experiments were performed using cultures enriched with individual BTEX compounds or BTEX as a mixture or benzoate alone or benzoate-BTEX mixture. An integrated Monod-type non-linear model was developed and a ratio between maximum growth rate (μmax) and half saturation constant (Ks) was used to fit the non-linear model. A higher μmax/Ks indicates a higher affinity to degrade BTEX compounds. Complete removal of BTEX mixture was observed by all the enriched cultures; however, the removal rates for individual compounds varied. Degradation rate and the type of removal kinetics were found to be dependent on the type of carbon source during the enrichment. Cultures enriched on toluene and those enriched on BTEX mixture were found to have the greatest μmax/Ks and cultures enriched on benzoate had the least μmax/Ks. Removal performances of the cultures enriched on all different carbon sources, including the ones enriched on benzoate or benzoate-BTEX mixture were also improved during a second exposure to BTEX. A molecular analysis showed that after each exposure to the BTEX mixture, the cultures enriched on benzoate and those enriched on benzoate-BTEX mixture had increased similarities to the culture enriched on BTEX mixture. © 2012 Springer Science+Business Media B.V. Source

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