aw water. The red colour is used for the zone indicating that the filter is being operated at either an extremely high or low velocity. The scale is constructed of aluminium or acrylic. Figure A1-2: Triangular weir (A) and rectangular weir (B). Outlet rectangular weir in a DyGF unit which combines constant (headloss ≤ s) and declining filtration rates. Figure A1-3. Example of a measuring scale (to be used in vertical position) A1.1.4. Movable overflow and drainage device for SSF This movable device is also called “goose neck” because it can be pulled up to be used as an overflow facility during SSF runs and push down to drain the supernatant water. Details of this device are presented in Figure A1-4. Figure A1-4: Details of the movable overflow and drainage (goose neck) device for SSF. A1-2
A1.2 Maintenance facilitating devices A1.2.1 Fast drainage valve The fast drainage valves are connected to the drainage system to facilitate the periodic hydraulic cleaning of CGF units. By quickly opening and closing the valves, changes of flow pattern are produced which assist in removing the material accumulated on the gravel. In Figure A1-5 two early designs for these types of valves are presented, one (A) based on experience in Peru by Pardón (1989) and the other (B) developed in Colombia by Cinara (Galvis et al, 1989) using a model which is also applied for milk cans. In both designs the operator faces the risk of becoming in contact with biologically active wash water, so the use of this type of valve is now discouraged. The commercially available butterfly valve is equipped with a handle, as shown in Figure A2-5. The house of the valve is made of cast iron, stainless steel or bronze. Its main characteristics include easy handling, complete sealing of the flow, low headloss and easy instalment and replacement. It can be easily connected to the outlet of the drainage system and an extension pipe can be installed after the fast opening valve to avoid the contact of the operator with the wash-water. It is now recommended that this valve be used in treatment units both first and second CGF stages. C Figure A1-5: Fast opening valves. (A) After experiences of Pardón (1989); (B) after experiences of Cinara (Galvis et al, 1989); (C) Commercial (“butterfly”) valve. References Galvis, G., Visscher, J.T., Quiroga, E., Latorre, J., Galvis, A., Duque, R., Cruz, C. (1989) Proyecto Integrado de Investigación y Demostración en Filtración Lenta en Arena. Informe Final. Versión Resumida. Cali, Colombia: Cinara. The Hague, The Netherlands, IRC International Water and Sanitation Centre. Pardon, M.O. (1989) Treatment of Turbid Surface Water for Small Community Supplies: PhD Thesis. University of Surrey. United Kingdom. A1-3
We are a wholesale supplier of products, solutions and services in water treatment.
We provide only businesses companies such as distributors, retailers, manufacturers and assemblers.
A catalog that includes products carefully selected from the most prestigious brands in the Water Treatment market, operative site, personalized services, logistics precise and efficient, flexible organization, but also the basic importance that is attributed to human factors and relationships with partners, are of Sinergroup Srl a reference for many companies of the sector.