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This paper presents the analysis of the variation of haloacetic acids (HAAs) for different pipe materials in a distribution system. The work involved an experimental study on a simulated distribution system assembled in the Hydraulic Laboratory of the Engineering Institute at the National Autonomous University of Mexico (Instituto de Ingeniería UNAM). Two different scenarios were investigated based on different pipe materials, variation of temperature and initial chlorine concentrations (4.0 and 4.5 mg/L). Feed water with varying amounts of organic content was dosed with varying amounts of chlorine concentration. Water samples were collected from different locations in the distribution system and analyzed for physicochemical properties and HAAs determination. The results of this research demonstrated that the concentration of HAAs in the different segments of the distribution systems varied depending on pipe material, initial chlorine concentration, pH, residence time and the presence of natural organic matter.

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In Mexico City, due to the excessive growth of the population, with more buildings, houses, other constructions and paving of streets, little permeable surfaces have been generated, increasing the volume of runoff that often causes flooding. Part of this problem was observed in the Tarango microbasin, where the Río Puerta Grande stream is located, with a length of 6.3 km, where there are some 53 discharges of urban wastewater that are discharged directly into the stream, which produces contamination, affecting its quality. It belongs to an Area of Environmental Value due to its ecological importance, so it is important to know its rainfall flow in order to have hydraulic and hydrological data, in order to establish a future water treatment design. Objective for which the calculation of the flow of pluvial origin of runoff in the micro-basin was carried out, with a return period of 25 years, in addition to also considering residual discharges, for which a flow of 49.10 m 3 /s was obtained, performing gauging to obtain the configuration of the channel, its speed and depth, in order to identify its behavior in dry season and after rains, comparing field data with the time adjustment curve (hydrograph).

The objective of this study was to evaluate the factors that affect the formation and diffusion of disinfection by-products, especially trihalomethanes (THM), in a laboratory-scale water distribution network constructed with three different pipe materials. Sampling locations were chosen on the basis of residence time, pipe material and mixing zone. Water samples were collected and analyzed for temperature, pH, total organic carbon, turbidity, free chlorine and THM. Experiments were carried out where two different flow directions at cross junctions were studied. It was observed that for incoming flow at 90° with varying flow rate, mixing was shown to be incomplete where inflows tend to bifurcate rather than mix completely. For two incoming flows in opposing direction (180°), solute mixing has shown to be perfect due to the collision of the fluid streams. The results demonstrated how THM concentration can greatly vary in the same water distribution network due to the impact of pipe material, residence time and the outcome of mixing at cross junctions.