COMPARISON BETWEEN HAZEN-WILLIAMS AND DARCY-WEISBACH EQUATIONS TO CALCULATE HEAD LOSS THROUGH CONVEYANCING TREATED WASTEWATER IN KERBALA CITY, IRAQ

Abstract

Reuse of wastewater has been widespreadin this era to support the watersustainability process. Therefore, treatedwastewater should be conveyed tosuitable places and adopted for differentuses. This study presents an empiricalrelationship between the Darcy-Weisbach and Hazen-Williams equationsfor four types of pipe material (ductileiron, GRP, concrete, and plastic) byusing WaterCAD Version 8i. Two hydraulicmodels were developed to estimatethe head loss in pipes by using differentdiameters: first, using pipe diametersfrom 800 mm to 1,200 mm for a flowrate of 1.16 m3/s, second, adopting pipediameter from 1,600 mm to 2,000 mm fora flow rate of 4.63 m3/s. The study resultsare the head loss values obtained from theDarcy-Weisbach and Hazen-Williamsequations, which were used to correlatethem using IBM SPSS Statistics. The correlationcoefficient between both equationsturned out to be 0.991, 0.990, 0.990,and 0.990 for ductile iron, GRP, concrete,and plastic pipe materials. Additionally,the relationship between head loss andpipe diameter is negatively proportionedfor both equations. Also, both head lossequation results are the same. The headloss values in the Darcy’s equation werehigher for ductile iron and GRP materials,while being lower for concreteand plastic materials for both models.Selecting concrete or plastic pipes toconvey treated wastewater is better thanother pipe materials. Another conclusionis that the pipe diameter affects the headloss magnitude irrespective of the kindof equation whether Darcy-Weisbach orHazen-William equation. Finally, thisrelationship is very useful for designersin converting the head loss valuesobtained using these equations