Search results for "Environmental biotechnology"
showing 10 items of 568 documents
Assessing theoretical flow velocity profile and resistance in gravel bed rivers by field measurements
2018
Previous studies showed that integrating a power velocity profile, deduced applying dimensional analysis and the incomplete self-similarity condition, the flow resistance equation for open channel flow can be obtained. At first, in this paper the relationship between the Gamma function of the power velocity profile, the channel slope and the Froude number, which was already empirically introduced in a previous paper, is now theoretically deduced. Then this relationship is calibrated using the field measurements of flow velocity, water depth and bed slope carried out in 101 reaches of gravel bed rivers available by literature. The proposed relationship for estimating Gamma function and the t…
Assessing the quality of service to customers provided by water utilities: A synthetic index approach
2017
Abstract Currently, water and sewer companies face the challenge of improving their quality of service to customers (QSC). Performance indicators are essential to monitor and benchmark the QSC of water companies; however, individual indicators do not provide a holistic evaluation of the quality of water and sewer services provided to customers. This study proposes an innovative QSC index based on distance-function techniques that makes it possible to compare changes in the QSC of water companies among locations and temporal periods. A case study assesses changes in QSC for a sample of Chilean water and sewer companies from 2007 to 2014. The results show that in spite of the efforts made by …
Biokinetic Behaviour of Autochthonous Halophilic Biomass at Different Salinity: Comparison Between Activated Sludge and Granular Sludge Systems
2017
The main goal of this study was the evaluation of the impact of increasing salinity on halophilic biomass in forms of flocculent and granular sludge for the treatment of hypersaline fish-canning wastewater, focusing on the metabolic behavior of autotrophic biomass. For this purpose, two sequencing batch reactors, one with aerobic granular sludge (GSBR) and the other with flocculent activated sludge (SBR) were monitored. In both reactors, a halophilic biomass was cultivated from a real saline wastewater collected from a fish-canning industry. The salt concentration was stepwise increased (2 gNaCl L-1) from 30 gNaCl L-1 to 50 gNaCl L-1. Therefore, ammonia and nitrite uptake rates for granular…
Bipolar membrane reverse electrodialysis for the sustainable recovery of energy from pH gradients of industrial wastewater: Performance prediction by…
2021
Abstract The theoretical energy density extractable from acidic and alkaline solutions is higher than 20 kWh m−3 of single solution when mixing 1 M concentrated streams. Therefore, acidic and alkaline industrial wastewater have a huge potential for the recovery of energy. To this purpose, bipolar membrane reverse electrodialysis (BMRED) is an interesting, yet poorly studied technology for the conversion of the mixing entropy of solutions at different pH into electricity. Although it shows promising performance, only few works have been presented in the literature so far, and no comprehensive models have been developed yet. This work presents a mathematical multi-scale model based on a semi-…
Synergistic integration of optical and microwave satellite data for crop yield estimation
2019
Developing accurate models of crop stress, phenology and productivity is of paramount importance, given the increasing need of food. Earth observation (EO) remote sensing data provides a unique source of information to monitor crops in a temporally resolved and spatially explicit way. In this study, we propose the combination of multisensor (optical and microwave) remote sensing data for crop yield estimation and forecasting using two novel approaches. We first propose the lag between Enhanced Vegetation Index (EVI) derived from MODIS and Vegetation Optical Depth (VOD) derived from SMAP as a new joint metric combining the information from the two satellite sensors in a unique feature or des…
Effect of macro and micro nutrients addition during anaerobic mono-digestion of grass silage in leach-bed reactors
2019
The effect of macro- (NH4Cl) (set I) and micro-nutrients (Fe, Ni, Co and Mo) (set II) addition on chemical oxygen demand (COD) solubilisation during anaerobic mono-digestion of grass silage was investigated in two sets of leach bed reactor experiments at 35°C. Results showed that addition of NH4Cl and micro-nutrients improved COD solubilisation by 18% (0.56 g SCOD g−1 volatile solids) and 7% (0.45 g SCOD g−1 VS), respectively than control. About 20–50% of the added micro-nutrients were bioavailable in the produced leachates, while the rest (50–80%) were adsorbed onto the grass silage. Results of biological methane potential assays showed that, specific methane yields of grass silage were im…
Testing steady-state analysis of single-ring and square pressure infiltrometer data
2016
Testing reliability of the saturated soil hydraulic conductivity, Ks, estimated by applying the steady-state single-ring (SR) model to the quasi steady-state infiltration rates obtained with a single-ring pressure infiltrometer (PI) increases confidence in the estimated Ks values. Determining a means to estimate Ks from infiltration data collected with a square infiltrometer allows the use of sources of different shapes. Using numerically simulated infiltration rates for six homogeneous soils ranging in texture from sand to silty clay loam, this investigation suggested an overall good performance of the SR model, with estimated Ks values differing by not more than 25% from the true values f…
Advances in designing drip irrigation laterals
2018
It is known that using paired laterals, in which two distribution pipes extend in opposite directions from a common manifold, contribute to increasing water use efficiency (WUE). Recently, an analytical procedure to optimally design paired drip laterals on uniform slopes was proposed. More recently, this design procedure was simplified by deriving simple explicit relationships, as a function of 16 calibration constants, with relative errors that were less than 2%. In this paper, further simple design relationships are derived that require only 3 calibration constants, thus more readily obtainable results are produced and the influence of the flow rate and diameter exponents of resistance eq…
Establishing soil loss tolerance: an overview
2016
Soil loss tolerance is a criterion for establishing if a soil is potentially subjected to erosion risk, productivity loss and if a river presents downstream over-sedimentation or other off-site effects are present at basin scale. At first this paper reviews the concept of tolerable soil loss and summarises the available definitions and the knowledge on the recommended values and evaluating criteria. Then a threshold soil loss value, at the annual temporal scale, established for limiting riling was used for defining the classical soil loss tolerance. Finally, some research needs on tolerable soil loss are listed.
Long-term monitoring of soil bulk density and erosion rates in two Prunus Persica (L) plantations under flood irrigation and glyphosate herbicide tre…
2021
Abstract Early season fruit production for the northern European market is highly intensive in fertilization, machinery, irrigation and the use of herbicides. Those conditions increase the soil losses and soil compaction and threaten the Sustainable Goals for Development of the United Nations by 2030. Long-term soil erosion measurements are necessary to determine the sustainability of agriculture managements. Moreover, soil erosion on flood irrigation land is a topic that request more surveys and research as rainfed sloping terrains attracted all the attention of scientists and research investment. Improved Stock Unearthing Method (ISUM) was applied to two 15 years-old herbicide treated fie…