Accuracy of Flowmeters Measuring Horizontal Flow in Fractured‐Rock Simulators by E. Randall Bayless

The UK Water Industry first became interested in Reed Bed Treatment Systems for sewage in 1985. Early problems were experienced with soil-based horizontal-flow systems of the Root Zone type. The problems were overcome by national co-ordination of a development programme and international co-operation by an EC Expert Contact Group. A number of different types of systems have now been developed and the systems are now being accepted. The paper reviews the development of these systems for secondary and tertiary treatment and nitrification and mentions development of systems for other forms of treatment. The design changes made to overcome the problems are described. These include the gradual move to the use of gravel-based systems because of the difficulty experienced with over-land flow in the soil systems. The sizing of the systems is described together with performance data for the original horizontal-flow and the more recently developed vertical-flow systems. Treatment at secondary and tertiary levels is illustrated and the potential for nitrification. Early problems with reed growth have been overcome by planting with port-grown seedlings. After 10 years the process is generally accepted by the Water Industry as an appropriate treatment for villages and there are now between 200 and 300 systems in operation.

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Up-flow roughing filtration: rehabilitation of a water treatment plant in Tarata, Bolivia

Water Science & Technology ◽

10.2166/wst.1998.0346 ◽

1998 ◽

Vol 37 (9) ◽

pp. 105-112 ◽

Cited By ~ 4

Author(s):

Ana María Ingallinella ◽

Luis María Stecca ◽

Martin Wegelin

Keyword(s):

Water Treatment ◽

Pilot Plant ◽

Laboratory Tests ◽

Treatment Plant ◽

Water Treatment Plant ◽

Horizontal Flow ◽

Design Parameters ◽

Sand Filters ◽

Chemical Products ◽

Made In

This paper presents the methodology used for the rehabilitation of the pretreatment stage in a water treatment plant for a village located in Bolivia which has 3500 inhabitants. The treatment plant was initially composed by horizontal-flow roughing filters and slow sand filters, but due to the high contents of colloidal turbidity of the providing source, it did not work properly. A plan of rehabilitation was made which comprised laboratory tests, pilot tests and proposal of modifications based on the results of previous stages. The laboratory tests were made in order to find the optimum conditions to coagulate the raw water. It was found that horizontal-flow roughing filters must be turned into up-flow roughing filters, so a pilot plant was built and was operated for three months in order to find suitable design parameters. The results obtained obtained during the operation of the pilot plant and the proposal of modifications are presented. The results of operation of the final plant, which are also reported, demonstrated the advantages of the up-flow roughing filtration as a pretreatment stage when it is necessary to add chemical products in small treatment plants.

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Pilot-plant experiments for improvement of polluted canal/klong water by rock-bed filtration

Water Science & Technology ◽

10.2166/wst.1997.0300 ◽

1997 ◽

Vol 35 (8) ◽

pp. 83-90

Author(s):

Shigeo Fujii ◽

Chiaki Niwa ◽

Mitsuo Mouri ◽

Ranjna Jindal

Keyword(s):

Organic Matter ◽

Pilot Plant ◽

Horizontal Flow ◽

Removal Mechanism ◽

Soluble Organic Matter ◽

Filter Media ◽

Canal Water ◽

Rock Bed ◽

One Year ◽

Filtration Technique

Applicability of the rock-bed filtration technique was investigated through pilot-plant experiments in Bangkok, Thailand. Polluted canal water was used as horizontal flow influent to two reactor channels filled with rocks. During one year operation, HRT, filter media, and aeration mode, were changed in several runs. The results showed that 1) the rock-bed filtration with aeration and the HRT more than 6 h can successfully improve polluted klong water by reducing the pollutants (e.g. 60-120mg/L of SS to 20-40 mg/L and 15-30 mg/L of BOD to 5-20 mg/L); 2) main removal mechanism seems to be the sedimentation resulting from the settleability enhanced by aeration, and the biofilm attached onto rocks also works in the reduction of soluble organic matter; 3) a combination of three rock sizes arranged in descending order showed best results; 4) longer HRT (13 h) produces better effluent but is not so effective if it exceeds 9 hours; 5) 60-70% of sediment IL was decomposed in a year, and porosity in rock beds reduced approximately 16%.

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The Model for Calculating Elastic Modulus and Poisson's Ratio of Coal Body

The Open Fuels & Energy Science Journal ◽

10.2174/1876973x20131011004 ◽

2013 ◽

Vol 6 (1) ◽

pp. 36-43 ◽

Cited By ~ 3

Author(s):

Ai Chi ◽

Li Yuwei

Keyword(s):

Elastic Modulus ◽

Poisson’S Ratio ◽

Fractured Rock ◽

Rock Block ◽

Poisson's Ratio ◽

Linear Elastic ◽

Study Results ◽

The Face ◽

Block Face ◽

Coal Rock

Coal body is a type of fractured rock mass in which lots of cleat fractures developed. Its mechanical properties vary with the parametric variation of coal rock block, face cleat and butt cleat. Based on the linear elastic theory and displacement equivalent principle and simplifying the face cleat and butt cleat as multi-bank penetrating and intermittent cracks, the model was established to calculate the elastic modulus and Poisson's ratio of coal body combined with cleat. By analyzing the model, it also obtained the influence of the parameter variation of coal rock block, face cleat and butt cleat on the elastic modulus and Poisson's ratio of the coal body. Study results showed that the connectivity rate of butt cleat and the distance between face cleats had a weak influence on elastic modulus of coal body. When the inclination of face cleat was 90°, the elastic modulus of coal body reached the maximal value and it equaled to the elastic modulus of coal rock block. When the inclination of face cleat was 0°, the elastic modulus of coal body was exclusively dependent on the elastic modulus of coal rock block, the normal stiffness of face cleat and the distance between them. When the distance between butt cleats or the connectivity rate of butt cleat was fixed, the Poisson's ratio of the coal body initially increased and then decreased with increasing of the face cleat inclination.

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