Time filter

Source Type

Arcadia, CA, United States

Ebacher G.,Ecole Polytechnique de Montreal | Besner M.-C.,Ecole Polytechnique de Montreal | Lavoie J.,Usine de Traitement Chomedey Ville de Laval | Jung B.S.,618 Michillinda Ave | And 2 more authors.
Journal of Water Resources Planning and Management

The usefulness of transient models depends on their predictive ability. Consequently, their results should ideally be validated with field data. Despite numerous theoretical developments in the area of surge analysis, comparisons between field and modeled data for large distribution systems (DSs) are scarce. Transient low-pressure events at a water treatment plant (WTP) resulted in negative pressures at numerous locations in the DS. Three distinct surge events were measured in a full-scale DS and modeled with transient analysis software. The simulated pressure profiles were compared with field data collected from 9-12 sites within the DS. The objective was to apply a commercial transient analysis algorithm to a large and detailed network model (≈15,000 nodes/pipes) to estimate transient pressure variations within the network. Results showed similar trends for the three low-pressure events analyzed: the modeled pressures matched reasonably well with the measured pressures, as long as they remained positive. Whenever the pressures reached negative values, the simulated amplitude was larger than that of the recorded pressures. Modeling parameters and factors that might explain such results were tentatively investigated. The importance of field data in understanding and confirming the model outputs is highlighted. © 2011 American Society of Civil Engineers. Source

Badruzzaman M.,618 Michillinda Ave | Pinzon J.,1000 North Ashley Drive | Oppenheimer J.,618 Michillinda Ave | Jacangelo J.G.,1199 North Fairfax Street Suite 410 | Jacangelo J.G.,Johns Hopkins University
Journal of Environmental Management

The promulgation of numeric nutrient criteria for evaluating impairment of waterbodies in Florida is underway. Adherence to the water quality standards needed to meet these criteria will potentially require substantial allocations of public and private resources in order to better control nutrient (i.e., nitrogen and phosphorus) releases from contributing sources. Major sources of nutrients include atmospheric deposition (195-380 mg-N/m2/yr, 6 to 16 mg-P/m2/yr), reclaimed water irrigation (0.13-29 mg-N/L, 0.02 to 6 mg-P/L), septic systems (3.3 × 103-6.68 × 103 g-N/person/yr, 0.49 × 103-0.85 × 103 g-P/person/yr) and fertilizer applications (8 × 106-24 × 106 mg-N/m2/yr). Estimated nitrogen loadings to the Florida environment, as calculated from the above rates are as follows: 5.9 × 109-9.4 × 109 g-N/yr from atmospheric deposition, 1.2 × 108-2.6 × 1010 g-N/yr from reclaimed water, 2.4 × 1010-4.9 × 1010 g-N/year from septic systems, and 1.4 × 1011 g-N/yr from fertilizer application. Similarly, source specific phosphorus loading calculations are also presented in this paper. A fraction of those nutrient inputs may reach receiving waterbodies depending upon site specific regulation on nutrient control, nutrient management practices, and environmental attenuation. In Florida, the interconnectivity of hydrologic pathways due to the karst landscape and high volumes of rainfall add to the complexity of tracking nutrient loads back to their sources. In addition to source specific nutrient loadings, this review discusses the merits of source specific markers such as elemental isotopes (boron, nitrogen, oxygen, strontium, uranium and carbon) and trace organic compounds (sucralose, gadolinium anomaly, carbamazepine, and galaxolide) in relating nutrient loads back to sources of origin. Although this review is focused in Florida, the development of source specific markers as a tool for tracing nutrient loadings back to sources of origin is applicable and of value to all other geographical locations. © 2012. Source

Badruzzaman M.,618 Michillinda Ave | Oppenheimer J.A.,618 Michillinda Ave | Jacangelo J.G.,40814 Stoneburner Mill Lane | Jacangelo J.G.,Johns Hopkins University
Water Research

Nitrogen and phosphorous loading into waterways from designated beneficial uses of reclaimed water is a growing concern in many parts of the United States. Numerous studies have documented that organic microconstituents present in the reclaimed water can be utilized as indicators of its influence on surface water bodies. However, little to no information is available on the environmental attenuation of these microconstituents relative to the nutrients, which is a critical component in determining the effectiveness or limitations of those markers as a tool for elucidating their origins. In this study, the stability of selected markers (sucralose, carbamazepine, gadolinium anomaly, iohexol, and atenolol) was evaluated through bench-scale studies designed to simulate environmental conditions associated with biodegradation, adsorption, and photolysis. The primary pathway for nitrogen reduction was biodegradation (greater than 99%) while the highest phosphorous removal was due to adsorption (30-80%). Soils with low organic content were selected for this study. Sucralose was the most recalcitrant microconstituent in the environment with less than 15% removal by adsorption, biodegradation, or photolysis. Iohexol was too susceptible to photolysis (90% removal), and atenolol was susceptible to biodegradation (60-80% removal). Gd anomaly was fairly stable (less than 30% removal) in the environment. Carbamazepine was another efficacious marker for wastewater, but was susceptible (50% removal) to photolysis. Of the selected microconstituents, only atenolol showed any similarity with the attenuation observed for nitrate and none of the microconstituents showed any similarity with the attenuation observed for phosphorus. © 2013 Elsevier Ltd. Source

Discover hidden collaborations