A critical evaluation of predictive models for rooted soil strength with application to predicting the seismic deformation of rooted slopes

This paper presents a comparative study of three different classes of model for estimating the reinforcing effect of plant roots in soil, namely (i) fibre pull-out model, (ii) fibre break models (including Wu and Waldron’s Model (WWM) and the Fibre Bundle Model (FBM)) and (iii) beam bending or p-y models (specifically Beam on a Non-linear Winkler-Foundation (BNWF) models). Firstly, the prediction model of root reinforcement based on pull-out being the dominant mechanism for different potential slip plane depths was proposed. The resulting root reinforcement calculated were then compared with those derived from the other two types of models. The estimated rooted soil strength distributions were then incorporated within a fully dynamic, plane-strain continuum finite element model to assess the consequences of the selection of rooted soil strength model on the global seismic stability of a vegetated slope (assessed via accumulated slip during earthquake shaking). For the particular case considered in this paper (no roots were observed to have broken after shearing), root cohesion predicted by the pull-out model is much closer to that the BNWF model, but is largely over-predicted by the family of fibre break models. In terms of the effects on the stability of vegetated slopes, there exists a threshold value beyond which the position of the critical slip plane would bypass the rooted zones, rather than passing through them. Further increase of root cohesion beyond this value has minimal effect on the global slope behaviour. This implies that significantly over-predicted root cohesion from fibre break models when used to model roots with non-negligible bending stiffness may still provide a reasonable prediction of overall behaviour, so long as the critical failure mechanism is already bypassing the root-reinforced zones. © 2019, The Author(s)

Treatment of campus wastewater by a pilot-scale constructed wetland utilizing Typha latifolia, Juncus acutus and Iris versicolor

Constructed wetland is a popular treatment method for different sources of wastewaters, being an alternative to conventional wastewater treatment methods that have operational and financial restrictions, especially for decentralized wastewater systems. A pilot-scale, continuous flow, subsurface flow wetland was constructed at the Cukurova University in Adana, Turkey. The system works on a multi-culture planting texture employing Typha latifolia, Junkus acutus and Iris versicolor. Removal efficiency of the system was observed for approximately one year with 1.2 m3/h steady inflow rate. Removal rates of 89.0±10.6%, 76.7±8.3% and 68.8±5.9% were achieved for TSS, COD and BODs, respectively. A high removal (95.4±8.3%) for fecal coliform was also observed. The obtained results imply that constructed wetlands are suitable for treatment of wastewaters originating from campuses in arid climate. © Triveni Enterprises, Lucknow

The uptake and translocation of hexavalent chromium and effects on growth and enzyme activity of Zea mays L

The present study was carried out to determine the uptake and translocation of hexavalent chromium (Cr (VI)) by Zea mays L. and its subsequent effects on plant growth parameters and enzyme activity. A pot experiment was performed using Zea mays L. seedlings irrigated with water contaminated by different concentrations of Cr (VI) ranging from 0.25 to 1.25 mmol for 51 days. Cr concentrations measured were greater in roots than in other parts of the plants. The concentration of Cr in roots increased significantly with increasing Cr (VI) concentration of irrigation water and harvest time. The relatively small amounts of Cr accumulated in the roots were transferred to the aerial parts. The accumulation and distribution pattern of Cr in different parts of the plants was observed as roots > leaf > stem > corn and cob. At the end of the experiment, plant height was by around 65% lower than that in control plants with the highest Cr (VI) level (1.25 mmol) in irrigation water. The GR and APX activities increased in leaf and root tissues with increasing Cr (VI) concentration of irrigation water. However, the activity of CAT showed sharp increase in the highest concentration of Cr (IV) following gradual decrease

The uptake and translocation of hexavalent chromium and effects on growth and enzyme activity of Zea mays L

The present study was carried out to determine the uptake and translocation of hexavalent chromium (Cr (VI)) by Zea mays L. and its subsequent effects on plant growth parameters and enzyme activity. A pot experiment was performed using Zea mays L. seedlings irrigated with water contaminated by different concentrations of Cr (VI) ranging from 0.25 to 1.25 mmol for 51 days. Cr concentrations measured were greater in roots than in other parts of the plants. The concentration of Cr in roots increased significantly with increasing Cr (VI) concentration of irrigation water and harvest time. The relatively small amounts of Cr accumulated in the roots were transferred to the aerial parts. The accumulation and distribution pattern of Cr in different parts of the plants was observed as roots > leaf > stem > corn and cob. At the end of the experiment, plant height was by around 65% lower than that in control plants with the highest Cr (VI) level (1.25 mmol) in irrigation water. The GR and APX activities increased in leaf and root tissues with increasing Cr (VI) concentration of irrigation water. However, the activity of CAT showed sharp increase in the highest concentration of Cr (IV) following gradual decrease

Utilization of leachate for irrigation in landfill cover soil remediation projects

A landfill is constructed space on the ground to store waste, as it gradually breaks down into chemically inactive material. The landfill is filled with garbage and covered with soil or quarry. The landfill remediation operation is responsible for the restoration of the site and creates a low hill planted with native plants indigenous to the area. The aim was to study the use of leachate water from solid waste landfill sites for irrigation of plant species which normally grow in the wild. The plant species were Althea rosea, Cynodon dactylon, Inula viscosa, Melilotus officinalis and Thymbra spicata. During the two years of the study the plants were irrigated with tap and leachate water under drought conditions. After the experiment the features of the soil samples were analyzed and it was seen that using leachate water to cultivate different kinds of plants increased the percentage of total N and organic matter, and the amount of P, K, Fe and Zn in the soil

Uptake and translocation of hexavalent chromium by selected species of ornamental plants

The uptake and translocation of hexavalent chromium (Cr (VI)) by four ornamental plant species was investigated. Aptenia cordofolia L., Brassica juncea L., Brassica oleracea L., and Alyssum maritima L. species were planted in peat growth medium and exposed to Cr (VI) with irrigation water in a range of concentrations from 0.05 to 1 mmol· -1 for 10 weeks. The results found in this study indicated that the Cr (VI) concentrations in irrigation water significantly affected the Cr uptake and translocation capacities and the growth responses of all four plants. The increases in the concentration of the Cr (VI) in the irrigation water increased the accumulation and translocation of Cr in the root and shoot of the plants. The Cr concentrations found in the shoots of tested plants were relatively low in comparison with the plants classified as Cr-hyperaccumulators. The Cr accumulation in the shoot of tested plants was recorded in the order of Alyssum maritima L. > Aptenia cordofolia L. > Brassica oleracea L. > Brassica juncea L., for the root the order was Brassica juncea L. > Brassica oleracea L. > Alyssum maritima L. > Aptenia cordofolia L

Renewable Energy Resources and Their Importance in Rural Areas in Turkey

Turkey is a net importer of energy and its imports continue to grow. As fossil fuel energy becomes scarcer, Turkey will likely face higher energy prices, energy disruptions, and greater energy insecurity within the next few decades unless important steps and measures towards alternative energy supplies, conservation, and proactive government policies are taken. Turkey has substantial renewable energy potential. Primary renewable energy resources in Turkey are hydro, biomass, wind, geothermal and solar. Turkey has several advantages to utilize renewable energy sources, but the potential benefits of renewable sources are not fully realized. Investments in renewable energy sources will not only reduce energy costs to rural consumers but they will also create new job opportunities for rural populations. Rural area households and industries in developing countries suffer greatly from energy scarcity. Energy, an essential need for every individual and for economic development, has always been lacking in rural areas of developing countries. The income of these rural populations depends largely on farming. Energy is needed primarily for pumping water for agriculture and domestic activities. Most of the energy needs in rural areas are met with traditional biomass for household cooking and heating, and human animal power for agriculture. Energy efficiency and production on the farm are important components for agriculture sustainability. This paper analyzes the potential of renewable energy sources and examines the negative effects of energy insufficiency in rural areas

Renewable Energy Resources and Their Importance in Rural Areas in Turkey

Turkey is a net importer of energy and its imports continue to grow. As fossil fuel energy becomes scarcer, Turkey will likely face higher energy prices, energy disruptions, and greater energy insecurity within the next few decades unless important steps and measures towards alternative energy supplies, conservation, and proactive government policies are taken. Turkey has substantial renewable energy potential. Primary renewable energy resources in Turkey are hydro, biomass, wind, geothermal and solar. Turkey has several advantages to utilize renewable energy sources, but the potential benefits of renewable sources are not fully realized. Investments in renewable energy sources will not only reduce energy costs to rural consumers but they will also create new job opportunities for rural populations. Rural area households and industries in developing countries suffer greatly from energy scarcity. Energy, an essential need for every individual and for economic development, has always been lacking in rural areas of developing countries. The income of these rural populations depends largely on farming. Energy is needed primarily for pumping water for agriculture and domestic activities. Most of the energy needs in rural areas are met with traditional biomass for household cooking and heating, and human animal power for agriculture. Energy efficiency and production on the farm are important components for agriculture sustainability. This paper analyzes the potential of renewable energy sources and examines the negative effects of energy insufficiency in rural areas

Use of sewage sludge in growth media for ornamental plants and its effects on growth and heavy metal accumulation

Sewage sludge is a thick sludge of solid materials which settle out from wastewater during the treatment process, whether the wastewater is being moved through a home septic system or a commercial sewage treatment plant. The sewage sludge tends to concentrate heavy metals and poorly biodegradable trace organic compounds as well as potentially pathogenic organisms. In this study, the use of sewage sludge obtained from Adana West Wastewater Treatment Plant as component of growth media for ornamentals, Aptenia cordifolia, Carpobrotus edulis and Bryophyllum tubiflorum was investigated. The study includes three treatments, sewage sludge + diatomite, sewage sludge + basaltic tuff and natural soil. The experimental period was sustained 90 days, and plants were irrigated by C1S1 class water in laboratory conditions. Plant growth, fresh and dry biomass production and heavy metal accumulation of plants were determined. The results of the study imply that the addition of sewage sludge to tuff enhanced plant growth. There was no difference between treatments for Aptenia cordifolia and Bryophyllum tubiflorum leaf, stem and root characteristics, but Carpobrotus edulis turned to brown in the end of the tenth week and they died in the natural soil and sewage sludge + diatomite treatments. The addition of sewage sludge to diatomite on the other hand increased the heavy metal uptake of plants. All of the plant roots accumulate significantly greater concentration of metals than stems. Every three ornamental plant species are an effective plant for possible remediation treatment in some contaminated and spoilt landscapes can be recovered

Phytoremediation of landfill leachate using Pennisetum clandestinum

PubMedID: 16114456Landfills are still the most widely used solid waste disposal method used across the world, Leachate generated from landfill areas exerts environmental risks mostly on surface and groundwater, with its high pollutant content, most notably metals, which cause an unbearable lower water quality. During dumping or after the capacity of the landfill has been reached, a decontamination and remediation program should be taken for the area. This study was conducted to assess the capacity and efficiency of Pennisetum clandestinum, a prostrate perennial plant, to accumulate chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), zinc (Zn) and lead (Pb). Leachate, taken from the Sofulu Landfill Site, was given to Pennisetum clandestinum for 180 days, in 3 dilution sets as 1/1, 1/2 and 1/4, in batch configuration. An additional control set was also installed for comparison. Results showed that, even though the metal content of soil had risen, plants accumulated 2 to 8.5 times higher concentrations than the control set. It is important to see, the plant showed almost no stress symptoms even if the set was fed by pure leachate. Pennisetum clandestinum was observed to accumulate metals mostly in the upper bodies, excluding Fe and Cu. 76% of accumulated Cr, 85% of Ni, 66% of Zn and 100% of Pb was observed to accumulate in above-ground parts, where only 20% of Cu and 4% of Fe was accumulated. Due to the high pollution tolerance of Pennisetum clandestinum, makes this plant suitable for decontamination and remediation of landfill sites