Analysis of changes in meteorological variables using Mann-Kendall and Sen's slope estimator statistical tests in Serbia

Artificial recharge of groundwater is achieved by putting surface water in basins, furrows, ditches, or other facilities where it infiltrates into the soil and moves downward to recharge aquifers. Artificial recharge is increasingly used for short- or long-term underground storage, where it has several advantages over surface storage, and in water reuse. Artificial recharge requires permeable surface soils. Where these are not available, trenches or shafts in the unsaturated zone can be used, or water can be directly injected into aquifers through wells. To design a system for artificial recharge of groundwater, infiltration rates of the soil must be determined and the unsaturated zone between land surface and the aquifer must be checked for adequate permeability and absence of polluted areas. The aquifer should be sufficiently transmissive to avoid excessive buildup of groundwater mounds. Knowledge of these conditions requires field investigations and, if no fatal flaws are detected, test basins to predict system performance. Water-quality issues must be evaluated, especially with respect to formation of clogging layers on basin bottoms or other infiltration surfaces, and to geochemical reactions in the aquifer. Clogging layers are managed by desilting or other pretreatment of the water, and by remedial techniques in the infiltration system, such as drying, scraping, disking, ripping, or other tillage. Recharge wells should be pumped periodically to backwash clogging layers. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s10040-001-0182-4.

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Artificial recharge of groundwater: hydrogeology and engineering

Developing uniformly formatted, densified feedstock from lignocellulosic biomass is of interest to achieve consistent physical properties such as size and shape, bulk and unit density, and durability, which significantly influence storage, transportation and handling characteristics, and, by extension, feedstock cost and quality. A variety of densification systems are considered for producing a uniform format feedstock commodity for bioenergy applications, including (i) pellet mill, (ii) cuber, (iii) screw extruder, (iv) briquette press, (v) roller press, (vi) tablet press, and (vii) agglomerator. Each of these systems has varying impacts on feedstock chemical and physical properties, and energy consumption. This review discusses the suitability of these densification systems for biomass feedstocks and the impact these systems have on specific energy consumption and end-product quality. For example, a briquette press is more flexible in terms of feedstock variables where higher moisture content and larger particles are acceptable for making good quality briquettes; or among different densification systems, a screw press consumes the most energy because it not only compresses but also shears and mixes the material. Pre-treatment options like pre-heating, grinding, steam explosion, torrefaction, and ammonia fiber explosion (AFEX) can also help to reduce specific energy consumption during densification and improve binding characteristics. Binding behavior can also be improved by adding natural binders, such as proteins, or commercial binders, such as lignosulfonates. The quality of the densified biomass for both domestic and international markets is evaluated using PFI (United States standard) or CEN (European standard). Published in 2011 by John Wiley & Sons, Ltd

Re-use of this article is permitted in accordance with the Terms and Conditions set out at http://wileyonlinelibrary.com/onlineopen#OnlineOpen_Terms

https://onlinelibrary.wiley.com/doi/pdf/10.1002/bbb.324

A review of biomass densification systems to develop uniform feedstock commodities for bioenergy application.

Soil erosion is a critical environmental problem throughout the world’s terrestrial ecosystems. Erosion inflicts multiple, serious damages in managed ecosystems such as crops, pastures, or forests as well as in natural ecosystems. In particular, erosion reduces the water-holding capacity because of rapid water runoff, and reduces soil organic matter. As a result, nutrients and valuable soil biota are transported. At the same time, species diversity of plants, animals, and microbes is significantly reduced. One of the most effective measures for erosion control and regeneration the degraded former soil is the establishment of plant covers. Indeed, achieving future of safe environment depends on conserving soil, water, energy, and biological resources. Soil erosion can be controlled through a process of assessment at regional scales for the development and restoration of the plant cover, and the introduction of conservation measures in the areas at greatest risk. Thus, conservation of these vital resources needs to receive high priority to ensure the effective protection of managed and natural ecosystems. This review article highlights three majors topics: (1) the impact of erosion of soil productivity with particular focus on climate and soil erosion; soil seal and crust development; and C losses from soils; (2) land use and soil erosion with particular focus on soil loss in agricultural lands; shrub and forest lands; and the impact of erosion in the Mediterranean terraced lands; and (3) the impact of plant covers on soil erosion with particular focus on Mediterranean factors affecting vegetation; plant roots and erosion control; and plant cover and biodiversity.

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Soil-Erosion and Runoff Prevention by Plant Covers: A Review

http://dl.mozh.org/uploads/141676044188471.pdf

Wastewater reuse in irrigation: a microbiological perspective on implications in soil fertility and human and environmental health.

Vegetated filter strips (VFS) are used recently for removal, at or near the source, of sediment and sediment-bound chemicals from cropland runoff. Vegetation within the flowpath increases water infiltration and decreases water turbulence, thus enhancing pollutant removal by sedimentation within filter media and infiltration through the filter surface. Field experiments have been conducted to examine the efficiency of vegetated filter strips for phosphorus removal from cropland runoff with 20 filters with varying length (2 to 15 m), slope (2.3 and 5%), and vegetated cover, including bare-soil plots as control. Artificial runoff used in this study had an average phosphorus concentration of 2.37 mg L(-1) and a sediment concentration of 2700 mg L(-1). The average phosphorus trapping efficiency of all vegetated filters was 61% and ranged from 31% in a 2-m filter to 89% in a 15-m filter. Filter length has been found to be the predominant factor affecting P trapping in VFS. The rate of inflow, type of vegetation, and density of vegetation coverage had secondary influences on P removal. Short filters (2 and 5 m), which are somewhat effective in sediment removal, are much less effective in P removal. Increasing the filter length beyond 15 m is ineffective in enhancing sediment removal but is expected to further enhance P removal. Sediment deposition, infiltration, and plant adsorption are the primary mechanisms for phosphorus trapping in VFS.

Phosphorus removal in vegetated filter strips.

The impact of vegetated filter strips (VFS) on sediment removal from runoff has been studied extensively in recent years. Vegetation is believed to increase water infiltration and decrease water turbulence thus enhancing sediment deposition within filter media. In the study reported here, field experiments have been conducted to examine the efficiency of vegetated filter strips for sediment removal from cropland runoff. Twenty filters with varying length, slope and vegetated cover were used under simulated runoff conditions with an average sediment concentration of 2700 mg/L. The filters were 2, 5, 10 and 15 m long with a slope of 2·3 and 5% and three types of vegetation. Three other strips with bare soil were used as a control. The experimental results showed that the average sediment trapping efficiency of all filters was 84% and ranging from 68% in a 2-m filter to as high as 98% in a 15-m long filter compared with only 25% for the control. The length of filter has been found to be the predominant factor affecting sediment deposition in VFS up to 10 m. Increasing filter length to 15 m did not improve sediment trapping efficiency under the present experimental conditions. The rate of incoming flow and vegetation cover percentage has a secondary effect on sediment deposition in VFS. Copyright © 2004 John Wiley & Sons, Ltd.

Experimental investigation of runoff reduction and sediment removal by vegetated filter strips

Effect of Application of Surfactants on Hydraulic Properties of Soils

Soil and water conservation practices have been promoted for a long time, in order to sustain agricultural activities and prevent environmental pollution. Vegetated filter strips (VFS) have been used to reduce sediment pollution into water bodies at or near the pollutant source. However, factors effecting VFS performance under natural conditions have not been well understood owing to the physical, time and financial limitations of field experiments. The use of well-validated simulation models to understand the performance of VFS and factors affecting sediment deposition is highly justified. The objective of this research is to investigate sediment trapping in VFS and to study various factors affecting VFS performance using the simulation model VFSMOD, which was developed by researchers at University of North Carolina. Recently, VFSMOD has been validated successfully by using 21 filters with varying length, slope and vegetated cover. A wide range of five parameters was selected for the simulations, namely filter length, filter slope, manning roughness coefficient, soil type and characteristics of incoming sediment from adjacent fields. Computer simulations revealed that the length of filter is the most significant factor affecting sediment trapping in VFS. The relative increase in trapping efficiencies was not linearly related to an increase in filter length. Inflow sediment class also has a major influence on sediment trapping in VFS. The trapping efficiency of clay sediments in a 15 m length VFS was 47% compared with 92% for silt from incoming sediment. Manning roughness coefficient had a moderate effect on sediment trapping and was more significant in short filters. Land slope and soil type of VFS had a minor influence on the performance of VFS. Copyright © 2001 John Wiley & Sons, Ltd.

Factors affecting sediment trapping in vegetated filter strips: simulation study using VFSMOD

Problem statement: Temperature trend's investigation is important for proper water resources management and urban planning. This study aims to investigate trends and distribution of temperature in the past thirty years for the Kingdo m of Saudi Arabia (KSA), which represents about 86% of the Arabian Peninsula's area. Approach: The trend in the temperature time series, includin g the recorded maximum, average and minimum daily values, were analyzed using non-parametric statistics. These were Mann-Kendall tau coefficient and Sen's slope estimator. Results: (1): The study showed a warming trend through 9 months of the year except in November to January where non- significant cooling trends were observed. (2): The most significant warming trend appears in the summer months of June, August and September around the central region of KSA. (3) Spatially, The northwestern and southern regions were the least af fected by the warming trend. Conclusion: The study concluded that KSA as well as the Arabian Peninsula are suffering from a considerable warming temperature trend, which is an important issue to b e considered for rural development and water resources management.

Majed Abu-Zreig

Papers

Phosphorus removal in vegetated filter strips.

Experimental investigation of runoff reduction and sediment removal by vegetated filter strips

Effect of Application of Surfactants on Hydraulic Properties of Soils

Factors affecting sediment trapping in vegetated filter strips: simulation study using VFSMOD

Temperature Trends and Distribution in the Arabian Peninsula