Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Water quality”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS2021

River streamflow, remotely-sensed water quality, and benthic composition of previously undescribed nearshore coral reefs in northern Puerto Rico

Land-based sediment stress represents a threat to many coral reefs in Puerto Rico primarily as a result of unrestricted land cover/land use changes and poor best management practices. The effects of such stresses have been documented along most coasts around the island. However, little attention has been paid to reefs located on the north coast, and very little is known about their composition and current state. Here, we present a study characterizing riverine inputs, water quality conditions, and benthic composition of two previously undescribed coral reefs (Tómbolo and Machuca reefs) located just eastward of the Río Grande de Manatí outlet in north-central Puerto Rico. This study utilizes a time series of remotely sensed ocean color products (diffuse vertical attenuation coefficient at 490 nm [Kd490] and chlorophyll-a concentration [Chl-a] estimated with data from the Visible Infrared Imaging Radiometer Suite [VIIRS]) to characterize water quality in this coastal region. In general, the months with relatively high mean daily river streamflow also coincide with months having the highest proportion of eastward wave direction, which can promote the eastward influence of river waters towards the two coral reefs sites. Kd490 and Chl-a showed a higher riverine influence closer to the watershed outlet. Kd490 and Chl-a monthly peaks also coincide with river streamflow highs, particularly at those pixels closer to shore. Tómbolo Reef, located farther eastward of the river outlet, shows a well-developed primary reef framework mainly composed of threatened reef-building species (Acropora palmata, Pseudodiploria) and high coral cover (19-51%). The benthos of Machuca Reef, located closer to the river outlet, is dominated by macroalgae with a significantly lower coral cover (0.2-2.7%) mainly composed of “weedy” coral species (Porites astroides, and S. radians). Cover of major benthic components correlates with distance from the river outlet, and with gradients in Kd490 and Chl-a, with higher coral cover and lower macroalgal cover farther from the river outlet. Coral cover at Tómbolo Reef is higher than what has been reported for similar sites around Puerto Rico and other Caribbean islands showing its ecological importance and, as up until now, an unrecognized potential refuge of reef-building threatened coral species.

benthic cover↗
NASA NTRS1973

Development of a laboratory prototype water quality monitoring system suitable for use in zero gravity

The development of a laboratory prototype water quality monitoring system for use in the evaluation of candidate water recovery systems and for study of techniques for measuring potability parameters is reported. Sensing techniques for monitoring of the most desirable parameters are reviewed in terms of their sensitivities and complexities, and their recommendations for sensing techniques are presented. Rationale for selection of those parameters to be monitored (pH, specific conductivity, Cr(+6), I2, total carbon, and bacteria) in a next generation water monitor is presented along with an estimate of flight system specifications. A master water monitor development schedule is included.

Misselhorn, J. E.↗
NASA NTRS1979

Water Quality Monitor

In the photo above, the cylindrical container being lowered into the water is a water quality probe developed by NASA's Langley Research Center for the Environmental Protection Agency (EPA) in an applications engineering project. It is part of a system- which also includes recording equipment in the helicopter-for on-the-spot analysis of water samples. It gives EPA immediate and more accurate information than the earlier method, in which samples are transported to a lab for analysis. Designed primarily for rapid assessment of hazardous spills in coastal and inland waters, the system provides a wide range of biological and chemical information relative to water pollution.

Source record↗
NASA NTRS1975

Development of a three dimensional numerical water quality model for continental shelf applications

A model to predict the distribution of water quality parameters in three dimensions was developed. The mass transport equation was solved using a non-dimensional vertical axis and an alternating-direction-implicit finite difference technique. The reaction kinetics of the constituents were incorporated into a matrix method which permits computation of the interactions of multiple constituents. Methods for the computation of dispersion coefficients and coliform bacteria decay rates were determined. Numerical investigations of dispersive and dissipative effects showed that the three-dimensional model performs as predicted by analysis of simpler cases. The model was then applied to a two dimensional vertically averaged tidal dynamics model for the Providence River. It was also extended to a steady state application by replacing the time step with an iteration sequence. This modification was verified by comparison to analytical solutions and applied to a river confluence situation.

Spaulding, M.↗
NASA NTRS2024

Big Cypress Water Resources: Using Earth Observations to Assess Water Quality in Big Cypress Reservation, FL

Upstream agricultural development and runoff are driving harmful algal blooms in the Big Cypress Reservation. The Seminole Tribe of Florida Environmental Resource Management Department monitors water quality in the Big Cypress Reservation, located on the north end of Big Cypress National Preserve. The Environmental Resource Management Department aims to incorporate Earth observations into its investigative approach, which consists of Geographic Information Systems and in situ water sampling. We assessed the feasibility of using Earth observations to measure harmful algal blooms over time and identify vulnerable areas. We analyzed data from multiple remote sensing platforms and sensors, including Landsat 8 Thermal Infrared Spectrometer(TIRS), Landsat 9 TIRS-2, Landsat 9 Operational Land Imager 2, Sentinel-2 MultiSpectral Instrument, and Sentinel-3 Ocean and Land Color Instrument. We determined that it was challenging to use Sentinel-3, Landsat 8, and Landsat 9 imagery for monitoring the canals within the Reservation, and that Sentinel-2 was the most capable platform for the study area. Using Sentinel-2, we created spectral indices for the detection of algal blooms. We used these indices to measure algal blooms at 8 stations across the Big Cypress Reservation. We then created time series and seasonal decompositions of in situ water sample data and indices to visualize relationships between datasets, along with correlation matrices. Our correlations were not conclusive. However, we found that the spectral indices have the potential to detect algal blooms. Lastly, we evaluated Maxar WorldView-3 imagery and found that using data from sensors with higher spatial resolutions would improve results.

Remote sensing↗
NASA NTRS1987

Recent developments in water quality monitoring for Space Station reclaimed wastewaters

This paper discusses the recent developments in water quality monitoring for Space Station reclaimed wastewaters. A preprototype unit that contains an ultraviolet absorbance organic carbon monitor integrated with pH and conductivity sensors is presented. The preprototype has provisions for automated operation and is a reagentless flow-through system without any gas/liquid interfaces. The organic carbon monitor detects by utraviolet absorbance the organic impurities in reclaimed wastewater which may be correlated to the organic carbon content of the water. A comparison of the preprototype organic carbon detection values with actual total organic carbon measurements is presented. The electrolyte double junction concept for the pH sensor and fixed electrodes for both the pH and conductivity sensors are discussed. In addition, the development of a reagentless organic carbon analyzer that incorporates ultraviolet oxidation and infrared detection is presented. Detection sensitivities, hardware development, and operation are included.

Small, John W.↗
NASA NTRS1973

Water quality determinations in the Virgin Islands from ERTS-A data.

The characterization of water quality in terms of absolute color values, using imagery from the ERTS-A satellite, imagery from aircraft, and ground truth measurements is discussed. The establishment of photometric standards resolvable by the ERTS-A sensors, as a means of determining atmospheric effects (which generally vary on sequential overpasses) is examined. The application of these techniques is demonstrated for the harbor of Charlotte Amalie on St. Thomas, Virgin Islands, which is characterized by the presence of many poluting factors.-

Egan, W. G.↗
NASA NTRS1979

Development of reclaimed potable water quality criteria

In order to minimize launch requirements necessary to meet the demands of long-term spaceflight, NASA will reuse water reclaimed from various on-board sources including urine, feces, wash water and humidity condensate. Development of reclamation systems requires the promulgation of water quality standards for potable reuse of the reclaimed water. Existing standards for domestic U.S. potable water consumption were developed, but do not consider the peculiar problems associated with the potable reuse of recycled water. An effort was made to: (1) define a protocol by which comprehensive reclaimed water potability/palatability criteria can be established and updated; and (2) continue the effort to characterize the organic content of reclaimed water in the Regenerative Life Support Evaluation.

Flory, D. A.↗
NASA NTRS1973

Water quality parameter measurement using spectral signatures

Regression analysis is applied to the problem of measuring water quality parameters from remote sensing spectral signature data. The equations necessary to perform regression analysis are presented and methods of testing the strength and reliability of a regression are described. An efficient algorithm for selecting an optimal subset of the independent variables available for a regression is also presented.

White, P. E.↗
NASA NTRS1978

Water quality and shellfish sanitation

The use of remote sensing techniques for collecting bacteriological, physical, and chemical water quality data, locating point and nonpoint sources of pollution, and developing hydrological data was found to be valuable to the Maryland program if it could be produced effectively and rapidly with a minimum amount of ground corroboration.

Eisenberg, M.↗
NASA NTRS1992

Microbiological concerns and methodological approaches related to bacterial water quality in spaceflight

A number of microbiological issues are of critical importance to crew health and system performance in spacecraft water systems. This presentation reviews an army of these concerns which include factors that influence water treatment and disinfection in spaceflight such as biofilm formation and the physiological responses of bacteria in clean water systems. Factors associated with spaceflight like aerosol formation under conditions of microgravity are also discussed within the context of airborne infections such as Legionellosis. Finally, a spectrum of analytical approaches is reviewed to provide an evaluation of methodological alternatives that have been suggested or used to detect microorganisms of interest in water systems. These range from classical approaches employing colony formation on specific microbiological growth media to direct (i.e. microscopic) and indirect (e.g. electrochemical) methods as well as the use of molecular approaches and gene probes. These techniques are critically evaluated for their potential utility in determining microbiological water quality through the detection of microorganisms under the influence of ambient environmental stress inherent in spaceflight water systems.

Pyle, Barry H.↗
NASA NTRS1991

The development of a volatile organics concentrator for use in monitoring Space Station water quality

A breadboard concept of a volatile organics concentrator (VOC) is manufactured and tested for optimized water-quality analysis in a space environment. The VOC system is attached to a gas chromatograph/mass spectrometer to analyze the volatile chemicals relevant to the operation of Space Station Freedom. The preliminary tests include: (1) comparisons with analyses based on direct on-column injections of standards; (2) analyses of iodinated volatile organics; (3) comparisons of nitrogen vs helium as the chromatography carrier gas; and (4) measurements of collection efficiency. The VOC can analyze EPA method-624 analytes at comparable detection using flame-ionization detection and can analyze volatile iodinated compounds. The breadboard has good reproducibility and can use nitrogen as a carrier gas; good results are noted for the collection and concentration levels and for water removal.

Bodek, Itamar↗
NASA NTRS1974

Photographic quantification of water quality in mixing zones

The waste effluent mixing zone is defined as the extent of a receiving water body utilized to dilute a waste charge to a concentration characteristic of a totally mixed condition. Color IR photography was used in conjunction with suspended solids water samples to quantitatively delineate the mixing zone resulting from the discharge of a paper mill effluent. Digital scanning microdensitometer data were used to estimate and delineate suspended solids concentrations on the basis of a semiempirical model. Model background, development, and implementation are described. Results indicate that the method is as reliable as conventional surface measuring techniques and is, in fact, more detailed. The method has direct application to the establishment of water quality guidelines, the development of both governmental and private sampling and surveillance programs, and the development of design and location criteria for industrial and municipal waste effluent outfalls.

Lillesand, T. M.↗
NASA NTRS1977

Lake water quality mapping from Landsat

In the project described remote sensing was used to check the quality of lake waters. The lakes of three Landsat scenes were mapped with the Bendix MDAS multispectral analysis system. From the MDAS color coded maps, the lake with the worst algae problem was easily located. The lake was closely checked, and the presence of 100 cows in the springs which fed the lake could be identified as the pollution source. The laboratory and field work involved in the lake classification project is described.

Scherz, J. P.↗
NASA NTRS2014

NASA COAST and OCEANIA Airborne Missions Support Ecosystem and Water Quality Research in the Coastal Zone

NASA has a continuing requirement to collect high-quality in situ data for the vicarious calibration of current and next generation ocean color satellite sensors and to validate the algorithms that use the remotely sensed observations. Recent NASA airborne missions over Monterey Bay, CA, have demonstrated novel above- and in-water measurement capabilities supporting a combined airborne sensor approach (imaging spectrometer, microradiometers, and a sun photometer). The results characterize coastal atmospheric and aquatic properties through an end-to-end assessment of image acquisition, atmospheric correction, algorithm application, plus sea-truth observations from state-of-the-art instrument systems. The primary goal is to demonstrate the following in support of calibration and validation exercises for satellite coastal ocean color products: 1) the utility of a multi-sensor airborne instrument suite to assess the bio-optical properties of coastal California, including water quality; and 2) the importance of contemporaneous atmospheric measurements to improve atmospheric correction in the coastal zone. The imaging spectrometer (Headwall) is optimized in the blue spectral domain to emphasize remote sensing of marine and freshwater ecosystems. The novel airborne instrument, Coastal Airborne In-situ Radiometers (C-AIR) provides measurements of apparent optical properties with high dynamic range and fidelity for deriving exact water leaving radiances at the land-ocean boundary, including radiometrically shallow aquatic ecosystems. Simultaneous measurements supporting empirical atmospheric correction of image data are accomplished using the Ames Airborne Tracking Sunphotometer (AATS-14). Flight operations are presented for the instrument payloads using the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter flown over Monterey Bay during the seasonal fall algal bloom in 2011 (COAST) and 2013 (OCEANIA) to support bio-optical measurements of phytoplankton for coastal zone research.

Airborne Instruments↗
NASA NTRS2010

Critical Readiness Review EHS Water Quality and Microbiology

Presentation reviews the status in reference to the Environmental, Health and Safety (EHS) of the water quality and microbiology for the International Space Station. It includes information about crew training, hardware delivery, and those items that will be returned for study.

Woo, Cindy↗