Download or read book The Simulated Effects of Wastewater Management Actions on the Hydrologic System and Nitrogen Loading Rates to Wells and Ecological Receptors Popponesset Bay Watershed Cape Cod Massachusetts written by Donald Walter and published by Createspace Independent Publishing Platform. This book was released on 2014-08 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The discharge of excess nitrogen into Popponesset Bay, an estuarine system on western Cape Cod, has resulted in eutrophication and the loss of eel grass habitat within the estuaries. Septic-system return flow in residential areas within the watershed is the primary source of nitrogen. Total Maximum Daily Loads (TMDLs) for nitrogen have been assigned to the six estuaries that compose the system, and local communities are in the process of implementing the TMDLs by the partial sewering, treatment, and disposal of treated wastewater at wastewater-treatment facilities (WTFs). Loads of waste-derived nitrogen from both current (1997-2001) and future sources can be estimated implicitly from parcel-scale water-use data and recharge areas delineated by a groundwater-flow model. These loads are referred to as "instantaneous" loads because it is assumed that the nitrogen from surface sources is delivered to receptors instantaneously and that there is no traveltime through the aquifer. The use of a solute-transport model to explicitly simulate the transport of mass through the aquifer from sources to receptors can improve implementation of TMDLs by (1) accounting for traveltime through the aquifer, (2) avoiding limitations associated with the estimation of loads from static recharge areas, (3) accounting more accurately for the effect of surface waters on nitrogen loads, and (4) determining the response of waste-derived nitrogen loads to potential wastewater-management actions. The load of nitrogen to Popponesset Bay on western Cape Cod, which was estimated by using current sources as input to a solute-transport model based on a steady-state flow model, is about 50 percent of the instantaneous load after about 7 years of transport (loads to estuary are equal to loads discharged from sources); this estimate is consistent with simulated advective traveltimes in the aquifer, which have a median of 5 years. Model-calculated loads originating from recharge areas reach 80 percent of the instantaneous load within 30 years; this result indicates that loads estimated from recharge areas likely are reasonable for estimating current instantaneous loads. However, recharge areas are assumed to remain static as stresses and hydrologic conditions change in response to wastewater-management actions.
Download or read book The Simulated Effects of Wastewater management Actions on the Hydrologic System and Nitrogen loading Rates to Wells and Ecological Receptors Popponesset Bay Watershed Cape Cod Massachusetts written by Donald A. Walter and published by CreateSpace. This book was released on 2013 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: The discharge of excess nitrogen into Popponesset Bay, an estuarine system on western Cape Cod, has resulted in eutrophication and the loss of eel grass habitat within the estuaries. Septic-system return flow in residential areas within the watershed is the primary source of nitrogen. Total Maximum Daily Loads (TMDLs) for nitrogen have been assigned to the six estuaries that compose the system, and local communities are in the process of implementing the TMDLs by the partial sewering, treatment, and disposal of treated wastewater at wastewater-treatment facilities (WTFs). Loads of waste-derived nitrogen from both current (1997–2001) and future sources can be estimated implicitly from parcel-scale water-use data and recharge areas delineated by a groundwater-flow model. These loads are referred to as “instantaneous” loads because it is assumed that the nitrogen from surface sources is delivered to receptors instantaneously and that there is no traveltime through the aquifer. The use of a solute-transport model to explicitly simulate the transport of mass through the aquifer from sources to receptors can improve implementation of TMDLs by (1) accounting for traveltime through the aquifer, (2) avoiding limitations associated with the estimation of loads from static recharge areas, (3) accounting more accurately for the effect of surface waters on nitrogen loads, and (4) determining the response of waste-derived nitrogen loads to potential wastewater-management actions. The load of nitrogen to Popponesset Bay on western Cape Cod, which was estimated by using current sources as input to a solute-transport model based on a steady-state flow model, is about 50 percent of the instantaneous load after about 7 years of transport (loads to estuary are equal to loads discharged from sources); this estimate is consistent with simulated advective traveltimes in the aquifer, which have a median of 5 years. Model-calculated loads originating from recharge areas reach 80 percent of the instantaneous load within 30 years; this result indicates that loads estimated from recharge areas likely are reasonable for estimating current instantaneous loads. However, recharge areas are assumed to remain static as stresses and hydrologic conditions change in response to wastewater-management actions.
Download or read book The Effect of Onsite Wastewater Treatment Systems on Nitrogen in Urban Watersheds of Metropolitan Atlanta Georgia written by Nahal Hoghooghi and published by . This book was released on 2016 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: High density onsite wastewater treatment systems (OWTSs) can cause contamination of both surface water and groundwater. However, the effect of OWTS on water quality at the watershed-scale is not well understood. We investigated the effect of OWTS on stream N concentrations during base flow in 24 watersheds in Metropolitan Atlanta, ranging in area from 0.18 to 8.8 km2. We found that total nitrogen (TN) and nitrate (NO3- ) concentrations increased linearly with increasing OWTS density above a threshold of about 75 OWTS km-2. Dual-isotope analysis of NO3- revealed that stream NO3--N originated predominately from OWTS in high density (HD) watersheds and from a combination of animal waste and perhaps organic N in low density (LD) watersheds. The effect of OWTS on NO3- load in an urban watershed where most of the homes use OWTS was simulated using the Soil Water Assessment Tool (SWAT). The model showed satisfactory daily stream flow and NO3- loads with Nash-Sutcliffe coefficients of 0.62 and 0.58 for the calibration period, and 0.67 and 0.33 for the validation period. OWTS caused an average increase in NO3- load of about 23% at the watershed scale and 29% at the sub-basin outlet with the highest density of OWTS. Failing OWTS were estimated to be 1% of the total systems and did not have a large impact on NO3- load. The NO3- load was 74% of the total N load in the watershed. Results from detailed monitoring using automated samplers in four headwater streams with a gradient in OWTS density demonstrated that the highest base-flow and storm-flow TN concentrations occurred in watersheds with the lowest density of OWTS and the highest density of OWTS, respectively. There were significant positive correlations between base flow NO3- concentrations and OWTS density. TN loads were also the highest at extremes of OWTS densities. This was due to the pattern in N concentrations and higher water yields at low and high OWTS density. These findings confirm the importance of OWTS on water quality in urban watersheds and can be used in other Piedmont regions where nitrogen Total Maximum Daily Loads (TMDL) are being developed.
Download or read book Flow Solute written by Andrew Michael Wentworth and published by . This book was released on 2015 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface water quality is a growing concern in the Willamette River Basin and elsewhere. The region's growing population is dependent on the availability of clean water for drinking water, irrigation, wastewater dilution, and wildlife habitat. Watershed management to produce economic goods and environmental services requires an understanding of basic hydrologic processes in addition to tools that accurately represent the interactions between human activity, biophysical processes, and climate change. In this study we developed a plug-in for the Envision modeling framework to explore where interactions between climate change and human activities are most likely to result in impaired water quality. This study has two primary objectives. The first is to develop a plug-in for Envision that can accurately simulate the effect of agricultural practices (e.g. fertilizer application rates and timing, crop selection, etc.) on the system's nitrogen budget. The second objective is to explore the landscape response to three future scenarios of changing climate, agricultural practices, and conservation actions as measured by nitrogen loading to surface waters in the Calapooia River Basin. The model we developed for this study was created by integrating algorithms from two widely used models: a conceptual hydrologic model and a nitrogen dynamics model. A number of changes were required to merge the two models and the accuracy of streamflow predictions suffered. The result of the scenario analysis was consistent with our expectations beginning the study: warmer and wetter climate scenarios were associated with higher annual nitrogen export rates, and policies that resulted in lower fertilizer application led to a decrease in annual nitrogen export rates.
Download or read book Applications of Activated Sludge Models written by Damir Brdjanovic and published by IWA Publishing. This book was released on 2015-02-15 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1982 the International Association on Water Pollution Research and Control (IAWPRC), as it was then called, established a Task Group on Mathematical Modelling for Design and Operation of Activated Sludge Processes. The aim of the Task Group was to create a common platform that could be used for the future development of models for COD and N removal with a minimum of complexity. As the collaborative result of the work of several modelling groups, the Activated Sludge Model No. 1 (ASM1) was published in 1987, exactly 25 years ago. The ASM1 can be considered as the reference model, since this model triggered the general acceptance of wastewater treatment modelling, first in the research community and later on also in practice. ASM1 has become a reference for many scientific and practical projects, and has been implemented (in some cases with modifications) in most of the commercial software available for modelling and simulation of plants for N removal. The models have grown more complex over the years, from ASM1, including N removal processes, to ASM2 (and its variations) including P removal processes, and ASM3 that corrects the deficiencies of ASM1 and is based on a metabolic approach to modelling. So far, ASM1 is the most widely applied. Applications of Activated Sludge Models has been prepared in celebration of 25 years of ASM1 and in tribute to the activated sludge modelling pioneer, the late Professor G.v.R. Marrais. It consists of a dozen of practical applications for ASM models to model development, plant optimization, extension, upgrade, retrofit and troubleshooting, carried out by the members of the Delft modelling group over the last two decades.
Download or read book National Estuary Study written by United States. Bureau of Sport Fisheries and Wildlife and published by . This book was released on 1970 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
