Search results for "Clogging"
showing 10 items of 14 documents
Experimental data of the laboratory investigation for the design of a new filter cartridge for water treatment
2019
Abstract The data provided here refers to the experimental laboratory investigation conducted in the Laboratory of Environmental and Maritime Hydraulics (LIDAM) of University of Salerno, Italy, with the aim of developing a new filtering cartridge for water treatment capable of overcoming the main inconveniences shown by usual commercial cartridges. Specifically, the proposed filtering cartridge is an economic, non-toxic, low-resistance and long-life cartridge, currently under a patent pending status, whose main advantage is to permit to significantly reduce, compared with the commercial cartridges, average head losses induced by the cartridge even for high clogging degrees, and to increase,…
Hydraulic conductivity and strength of pervious concrete for deep trench drains
2019
Abstract Pervious concrete for deep trench drains, used to stabilise slopes, must meet many requirements, namely, adequate hydraulic conductivity, adequate shear strength a few days after pouring, capacity to act as a protective filter for soils in which the drain is installed, good resistance to clogging and adequate residual hydraulic conductivity. In current engineering practice, the composition of pervious concrete for drains is improperly selected according to criteria used for no-fines concrete for road pavements. To detect more suitable and specific criteria, a laboratory investigation has been conducted aimed at identifying the composition and the properties of pervious concrete sat…
Long Term Efficiency Analysis of Infiltration Trenches Subjected to Clogging
2018
Abstract: In recent years, limitations linked to traditional urban drainage schemes have been pointed out and new approaches were developed introducing more natural methods for retaining and/or disposing of stormwater. Such practices include infiltration and storage tanks in order to reduce the peak flow and retain part of the polluting components. The impact of such practices on stormwater quantity and quality is not easily assessable because of the complexity of physical and chemical processes involved. In such cases, integrated urban drainage models may play a relevant role providing tools for long term analysis. In this study, the effect of the clogging phenomenon has been assessed by m…
Anaerobic thermophilic (55°C) treatment of TMP whitewater in reactors based on biomass attachment and entrapment
1999
Abstract Thermomechanical pulping (TMP) whitewater was treated in thermophilic (55°C) anaerobic laboratory-scale reactors using three different reactor configurations. In all reactors up to 70 % COD removals were achieved. The anaerobic hybrid reactor, composed of an upflow anaerobic sludge blanket (UASB) and a filter, gave degradation rates up to 10 kg COD/m 3 d at loading rates of 15 kg COD/m 3 d and hydraulic retention time (HRT) of 3.1 hours. The anaerobic multi-stage reactor, consisting of three compartments, each packed with granular sludge and carrier elements, gave degradation rates up to 9 kg COD/m 3 d at loading rates of 15–16 kg COD/m 3 d, and HRT down to 2.6 hours. Clogging and …
The Permeable Concrete: A Low Energy Consumption Solution for Deep Draining Trenches
2018
The reduction of pore water pressures is one of the very effective measures to improve the stability conditions of marginally stable water-bearing slopes or to stabilise landslides. For this purpose the trench drains have been used long since. Like filling material of deep trenches the permeable concrete can be effectively employed. It presents relatively high hydraulic conductivity, filtering capacity in order to prevent the internal erosion of the soil in which the trench drain is installed, enough residual hydraulic conductivity after possible clogging, sufficient shear strength after a short curing time to avoid the instabilisation of adjacent previously built panels or piles. Results o…
Evaluation of clogging in full-scale subsurface flow constructed wetlands
2016
Abstract Treatment processes that occur in constructed wetlands can result in gradual clogging of the porous medium. Clogging may result in hydraulic malfunction and/or reduced treatment performance. The aim of this study was to analyze the hydraulic aspects of horizontal subsurface flow (H-SSF) constructed wetlands (CWs), and, in particular, to investigate the clogging phenomena through in situ measurements of hydraulic conductivity of the gravel bed, quantification of accumulated clog matter and flow paths visualization by means of tracer tests. Removal efficiencies of chemical and physical contaminants were also assessed. Experiments were carried out in three full-scale H-SSF CWs in Sici…
Assessment of clogging in constructed wetlands by saturated hydraulic conductivity measurements
2019
Abstract This study aims at defining a methodology to evaluate Ks reductions of gravel material constituting constructed wetland (CW) bed matrices. Several schemes and equations for the Lefranc's test were compared by using different gravel sizes and at multiple spatial scales. The falling-head test method was implemented by using two steel permeameters: one impervious (IMP) and one pervious (P) on one side. At laboratory scale, mean K values for a small size gravel (8–15 × 10−2 m) measured by the IMP and the P permeameters were equal to 19,466 m/d and 30,662 m/d, respectively. Mean Ks values for a big size gravel (10–25 × 10−2 m) measured by the IMP and the P permeameters were equal to 12,…
Stormwater infiltration trenches: a conceptual modelling approach.
2009
In recent years, limitations linked to traditional urban drainage schemes have been pointed out and new approaches are developing introducing more natural methods for retaining and/or disposing of stormwater. These mitigation measures are generally called Best Management Practices or Sustainable Urban Drainage System and they include practices such as infiltration and storage tanks in order to reduce the peak flow and retain part of the polluting components. The introduction of such practices in urban drainage systems entails an upgrade of existing modelling frameworks in order to evaluate their efficiency in mitigating the impact of urban drainage systems on receiving water bodies. While s…
Hydrological and hydraulic behaviour of a surface flow constructed wetland treating agricultural drainage water in northern Italy.
2020
Abstract A surface flow constructed wetland (SFCW) treating agricultural drainage water was investigated with the aim to detect modifications in hydrological and hydraulic characteristics after more than a decade of operation. Ponded infiltration tests were conducted to estimate the saturated hydraulic conductivity, Ks, of the surface soil layer at the point scale. At the global scale, infiltration rate, i, was computed from the water balance to detect leakages from the pervious wetland surface. Tracer tests were conducted to analyse the existence of preferential flow inside the system and to estimate its hydraulic retention time (HRT). Clogging phenomena occurred given a mean Ks value of 3…
Air lift relevance in a side-stream MBR system
2006
Nowadays, two main MBR configurations are developed in wastewater treatment (Fig. 1a and b). The former is based on a side stream membrane module position, it is generally developed for the industrial wastewater treatment because of its compactness even if it requires more energy due to the necessity of using high suspension flow rate recycles throughout the membrane module to minimise fouling rates [1]. With this configuration the membrane maintenance is easy because of the side stream position of the membrane module relatively to the bioreactor. The second configuration is based on the immersion of membrane module directly inside the bioreactor. This configuration is more extensive becaus…