The previously successful British merchant houses on the west coast of South America faced significant problems between the two world wars. Earlier historians have referred to difficulties such as the volatility of commodity prices, the organisation and structure of the firms, and changes in...

The previously successful British merchant houses on the west coast of South America faced significant problems between the two world wars. Earlier historians have referred to difficulties such as the volatility of commodity prices, the organisation and structure of the firms, and changes in...

This study aimed to prepare zeolite from rice hull, characterize the prepared zeolite and apply it in the removal of nitrate in water. Pretreatment of rice hull before ashing was done using distilled water and 1M HCl.  Purity of the rice hull ashes obtained in the process was verified by...

Animal waste from concentrated animal feeding operations (CAFOs) is a significant contributor to the nitrate contamination of groundwater. Some manures also contain heavy metals and salts that may build up either in cropland or groundwater. To find cost-effective policies for pollution reduction...

Many environmental problems are due to damages caused by stock of pollutants which accumulate with time lag to their emission. In this paper, we focus on nitrates used in agriculture which can pollute groundwater years after their initial use. A dynamic optimal control problem with heterogeneous...

Socio-economic, climate and agricultural stress on water resources have resulted in increased global demand for water while at the same time the proportion of potential water resources which are adversely affected by sodification/salinisation, metals, nitrates, and organic chemicals has...

Nitrogen is essential to improving agricultural production systems, explaining why the contamination of groundwater by this nutrient is widespread. The aim of this paper was to describe data collected over 9 years on estimated leaching levels using a simple computation procedure and measurements...

Groundwater management can be effectively implemented by mapping groundwater contamination. Intense agricultural activities and land overexploitation have resulted in groundwater contamination, which is becoming a critical issue, specifically in areas where fertilizers are extensively used on...

The complexities and challenges in quantifying N leaching have led to development of a range of measurement and modelling techniques, but none are widely applied. Observations that N moves more slowly than water through the soil profile has resulted in different approaches being used to simulate...

Promoting the nitrogen oxide (NOx) absorption step is the major challenge for simultaneous removal of sulfur dioxide (SO2) and NOx in wet flue gas desulfurization. This paper studied NOx absorption and absorption product formation in limestone slurry. The effect of CaCO3 concentration, NOx...

There are many factors controlling groundwater pollution and vulnerability. However, the factors’ weights are still not reasonably investigated. In order to assess groundwater quality and the controlling factors in semiarid region, 178 groundwater samples were collected and analyzed for...

Nutrient emissions from animal feeding operations continue to degrade water and air quality. New regulations will limit the amounts of nutrients that can be locally applied to land. In this article, a structural-dynamic model of a livestock-crop operation is calibrated with data from a...

High levels of nitrates in groundwater pose a risk to human health. In this study, we selected areas with typical agricultural nitrate pollution in northeast China as study sites. We then collected groundwater samples for nitrate nitrogen content analysis using the Four Step method developed by...

A validation study has been performed using the Soil and Water Assessment Tool (SWAT) model with data collected for the Upper Maquoketa River Watershed (UMRW), which drains over 16,000 ha in northeast Iowa. This validation assessment builds on a previous study with nested modeling for the UMRW...

Too much nitrogen (N) in surface water is harmful to aquatic life. Subsurface drains, some along with surface inlets, are commonly used for drainage of agricultural land in humid regions and contribute unknown N amounts to surface water. Quantification of relative amounts moving through...

A 45% reduction in riverine total nitrogen flux from the 1980–1996 time period is needed to meet water quality goals in the Mississippi Basin and Gulf of Mexico. This paper addresses the goal of reducing nitrogen in the Mississippi River through three objectives. First, the paper outlines an...

Market definition according to reducing pollution at least cost whith transferable rights for manure spreading - Concepts from transferable discharge permits were applied to the context of nitrogen surplus of animal origin in Brittanny. We simulated markets for spreading rights in some local...

Integrated assessment frameworks which can account comprehensively for the benefits related to water quality improvements have not yet been established. The main challenge is to link economic valuation with hydrological data in an appropriate way. We here explore the so-called 'impact pathway...

The creation of a new irrigated area influences the pollutants exported from the zone and, consequently, the quality of receiving water bodies. The aim of this study was to analyze the masses of the main pollutants exported by an area before and during its gradual transformation into irrigated...

In the design of wood-based, enhanced-denitrification bioreactors to treat nitrate in agricultural drainage, the consideration of the highly variable flow rates and nitrate concentrations inherent to many drainage systems is important. For optimized mitigation of these nitrate loads, it may be...

The computer based model presented in this paper regards strategies for water supply companies to deal with nitrate pollution of groundwater aquifers. In Germany, as well as in many other European regions, nitrate pollution is one of the most important problems for water protection and water...

Groundwater constitutes the largest single source of fresh water in many parts of the world and provides a risk buffer to sustain critical water demands during cyclic and prolonged dry periods, especially in semi-arid and arid regions. However, unprecedented socio-economical growths are...

This study determines the spatial and temporal distribution of nitrate content within the water-supply wells in the Mancha Oriental System (MOS) for the period 1998–2003 and presents an example of the multiple nitrate pollution sources in the El Salobral–Los Llanos Domain (SLD, southwestern...

Dissemination of information to decision-makers and enhanced methods of public participation are often put forward as antidotes to a perceived disconnect between risk assessment and risk communication in the public domain. However, mechanisms that support both the provision of routine, timely...

The adjustable control-variation weight (ACW)-gradient method proposed by Weinreb [Optimal Control with Multiple Bounded Inputs, Department of Electrical Engineering, Stanford University, Stanford, 1985, p. 148] is put to the test in finding optimal control laws for an optimisation problem with...