Effects of type of flow, plants and addition of organic carbon in the removal of zinc and chromium in small-scale model wetlands

Constructed wetlands are used for the treatment of wastewater containing metals. In order to clarify the role of plants, flow and the impact of organic matter, an investigation of three factors, each at two different levels, was carried out in small-scale model wetlands. The evaluated factors and levels were: type of flow (subsurface and surface); presence of plants (planted with Typha latifolia and unplanted) and addition of organic matter (with and without). Eight different experimental units were run for a year. The units were fed with synthetic wastewater containing chromium (VI) (1.5 mg L−1), zinc (1.5 mg L−1), macro, micronutrients and organic matter (to those units in which this factor was being investigated). Subsurface flow wetlands showed a significantly higher rate of chromium removal in comparison with surface flow systems (97 and 60 mg m−2 d−1, respectively). Planted systems removed significantly more chromium compared to unplanted systems (85 and 76 mg m−2 d−1, respectively), and the addition of organic matter increased the removal rate in a comparison with the units without it (88 and 69 mg m−2 d−1, respectively). Similar results were found for zinc; however, the addition of organic matter made no significant difference to zinc removal.

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Étude quantitative de l'érosion en aval des dissipateurs d'énergie type auge

Canadian Journal of Civil Engineering ◽

10.1139/l01-091 ◽

2002 ◽

Vol 29 (2) ◽

pp. 201-210 ◽

Cited By ~ 2

Author(s):

A El Amri ◽

J L Verrette

Keyword(s):

Energy Dissipation ◽

The Other ◽

Scale Model ◽

Small Scale ◽

Other Hand ◽

Energy Dissipators ◽

The Impact ◽

Small Scale Model ◽

Impact Distance

Scour tests on downstream roller bucket energy dissipators have shown that, at the equilibrium, bed characteristics are mainly influenced by the discharge and by the height of the bucket lip. The discharge affects scour characteristics, without however modifying the shape of the bed. On the other hand, the height of the bucket lip simultaneously affects scour characteristics and the shape of the bed mainly in the vicinity of the structure. In the latter area, for larger values of the height of the bucket lip, one observes a deposition with a small depression on the top and, on the contrary, when the height of the bucket lip is small, one observes an erosion. Both the depth of scour and the thickness of the deposit increase proportionally to the height of the bucket lip. Values of the other bed characteristics decrease slightly with the height of the bucket lip to reach a minimum, then they increase for higher values of the height of the bucket lip. Comparison of bed characteristics at the equilibrium with the literature shows that theory overestimates the depth of the scour measured in the laboratory by an average of 68% for the three values of discharge, underestimates the impact distance by about 6% for low discharges, and overestimates it by 10% for the highest discharge.Key words: hydraulic energy dissipation, roller bucket, scour mecanism, scour, small-scale model.

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Preventing rattailed maggot incursion into dairy sheds

New Zealand Plant Protection ◽

10.30843/nzpp.2009.62.4792 ◽

2009 ◽

Vol 62 ◽

pp. 99-102 ◽

Cited By ~ 1

Author(s):

D.J. Wilson ◽

P.J. Gerard ◽

J.E. de Villiers

Keyword(s):

Organic Matter ◽

New Zealand ◽

Scale Model ◽

Small Scale ◽

Dairy Effluent ◽

Barrier Methods ◽

Sensitive Areas ◽

High Concentrations ◽

Set Up ◽

Small Scale Model

Rattailed maggots are the larvae of hover flies (Diptera Syrphidae) of which there are about 40 species in New Zealand many of them native The adults are important pollinators and the larvae live in water and mud feeding on rotting organic matter High concentrations occur in dairy effluent bunkers and become health and sanitary issues when prepupal larvae seeking suitable pupation sites exit bunkers and invade nearby dairy sheds Replicated small scale model bunkers were set up to test barrier methods that could prevent maggots entering sensitive areas and divert them to suitable pupation sites Known numbers of migratory prepupal larvae were placed in the model bunkers and their movements recorded over a timed period Both round piping and angular strips proved effective barriers while soil sand and sawdust were all equally attractive as a pupation medium

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STUDY OF POSITIVE PRESSURE VENTILATION IN ROOM FIRES USING A SMALL-SCALE MODEL

Heat Transfer Research ◽

10.1615/heattransres.2018025564 ◽

2019 ◽

Vol 50 (3) ◽

pp. 243-261

Author(s):

T. Y. Yeung ◽

W. K. Chow

Keyword(s):

Positive Pressure Ventilation ◽

Scale Model ◽

Positive Pressure ◽

Small Scale ◽

Room Fires ◽

Small Scale Model

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Hydrolysis of organic wastewater particles in laboratory scale and pilot scale biofilm reactors under anoxic and aerobic conditions

Water Science & Technology ◽

10.2166/wst.1998.0805 ◽

1998 ◽

Vol 38 (8-9) ◽

pp. 179-188 ◽

Cited By ~ 4

Author(s):

K. F. Janning ◽

X. Le Tallec ◽

P. Harremoës

Keyword(s):

Organic Matter ◽

Mass Balance ◽

Particulate Organic Matter ◽

Removal Rate ◽

Pilot Scale ◽

Laboratory Scale ◽

Synthetic Wastewater ◽

Aerobic Conditions ◽

Biofilm Reactors ◽

Hydrolysis Of

Hydrolysis and degradation of particulate organic matter has been isolated and investigated in laboratory scale and pilot scale biofilters. Wastewater was supplied to biofilm reactors in order to accumulate particulates from wastewater in the filter. When synthetic wastewater with no organic matter was supplied to the reactors, hydrolysis of the particulates was the only process occurring. Results from the laboratory scale experiments under aerobic conditions with pre-settled wastewater show that the initial removal rate is high: rV, O2 = 2.1 kg O2/(m3 d) though fast declining towards a much slower rate. A mass balance of carbon (TOC/TIC) shows that only 10% of the accumulated TOC was transformed to TIC during the 12 hour long experiment. The pilot scale hydrolysis experiment was performed in a new type of biofilm reactor - the B2A® biofilter that is characterised by a series of decreasing sized granular media (80-2.5 mm). When hydrolysis experiments were performed on the anoxic pilot biofilter with pre-screened wastewater particulates as carbon source, a rapid (rV, NO3=0.7 kg NO3-N/(m3 d)) and a slowler (rV, NO3 = 0.3 kg NO3-N/(m3 d)) removal rate were observed at an oxygen concentration of 3.5 mg O2/l. It was found that the pilot biofilter could retain significant amounts of particulate organic matter, reducing the porosity of the filter media of an average from 0.35 to 0.11. A mass balance of carbon shows that up to 40% of the total incoming TOC accumulates in the filter at high flow rates. Only up to 15% of the accumulated TOC was transformed to TIC during the 24 hour long experiment.

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Integrated Process for Textile Cotton Waste (TCW) Valorization: Waste-to-Energy and Wastewater Decontamination

Volume 6B: Energy ◽

10.1115/imece2016-66706 ◽

2016 ◽

Author(s):

A. Ribeiro ◽

C. Vilarinho ◽

J. Araújo ◽

J. Carvalho

Keyword(s):

Raw Materials ◽

Removal Rate ◽

Low Cost ◽

Calorific Value ◽

Waste To Energy ◽

Synthetic Wastewater ◽

Small Scale ◽

World Population ◽

Cotton Waste ◽

Textile Industries

The increasing of world population, industrialization and global consuming, existing market products existed in the along with diversification of raw materials, are responsible for an exponential increase of wastes. This scenario represents loss of resources and ultimately causes air, soils and water pollution. Therefore, proper waste management is currently one of the major challenges faced by modern societies. Textile industries represents, in Portugal, almost 10% of total productive transforming sector and 19% of total employments in the sector composed by almost 7.000 companies. One of the main environmental problems of textile industries is the production of significant quantities of wastes from its different processing steps. According to the Portuguese Institute of Statistics (INE) these industries produce almost 500.000 tons of wastes each year, with the textile cotton waste (TCW) being the most expressive. It was estimated that 4.000 tons of TCW are produced each year in Portugal. In this work an integrated TCW valorisation procedure was evaluated, firstly by its thermal and energetic valorisation with slow pyrolysis followed by the utilization of biochar by-product, in lead and chromium synthetic wastewater decontamination. Pyrolysis experiments were conducted in a small scale rotating pyrolysis reactor with 0.1 m3 of total capacity. Results of pyrolysis experiments showed the formation of 0,241 m3 of biogas for each kilogram of TCW. Results also demonstrated that the biogas is mostly composed by hydrogen (22%), methane (14 %), carbon monoxide (20%) and carbon dioxide (12%), which represents a total high calorific value of 12.3 MJ/Nm3. Regarding biochar, results of elemental analysis demonstrated a high percentage of carbon driving its use as low cost adsorbent. Adsorption experiments were conducted with lead and chromium synthetic wastewaters (25, 50 and 100 mg L−1) in batch vessels with controlled pH. It was evaluated the behaviour of adsorption capacity and removal rate of each metal during 120 minutes of contact time using 5, 10 and 50 g L−1 of adsorbent dosage. Results indicated high affinity of adsorbent with each tested metal with 78% of removal rate in chromium and 95% in lead experiments. This suggests that biochar from TCW pyrolysis may be appropriated to wastewaters treatment, with high contents of heavy metals and it can be an effective alternative to activated carbon.

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Wave Energy Hyperbaric Device for Electricity Production

Volume 5: Ocean Space Utilization; Polar and Arctic Sciences and Technology; The Robert Dean Symposium on Coastal and Ocean Engineering; Special Symposium on Offshore Renewable Energy ◽

10.1115/omae2007-29743 ◽

2007 ◽

Cited By ~ 7

Author(s):

Segen F. Estefen ◽

Paulo Roberto da Costa ◽

Eliab Ricarte ◽

Marcelo M. Pinheiro

Keyword(s):

Power Generation ◽

Wave Energy ◽

Experimental Results ◽

Electricity Production ◽

Scale Model ◽

Small Scale ◽

Regular Waves ◽

Hyperbaric Chamber ◽

Small Scale Model

Wave energy is a renewable and non-polluting source and its use is being studied in different countries. The paper presents an overview on the harnessing of energy from waves and the activities associated with setting up a plant for extracting energy from waves in Port of Pecem, on the coast of Ceara State, Brazil. The technology employed is based on storing water under pressure in a hyperbaric chamber, from which a controlled jet of water drives a standard turbine. The wave resource at the proposed location is presented in terms of statistics data obtained from previous monitoring. The device components are described and small scale model tested under regular waves representatives of the installation region. Based on the experimental results values of prescribed pressures are identified in order to optimize the power generation.

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