Implementation of an extensive urban runoff monitoring program, targeting the quantification of heavy metal and organic micropollutant loads, necessitated the development of an autonomous water sampler. The design requirements for the device were to fulfill flow-proportional continuous composite sampling of urban runoff events in a widely customizable, relatively inexpensive, and simple way. In this paper, we introduce the concept along with the experiences gained from the first several months of field tests at seven pilot areas in Hungary that represent a wide range of urban environments. During the test period, prototype samplers were placed in natural (urban) streams as well as stormwater drainage pipes, resulting in a total of 97 automatic composite runoff samples. At two sites, an additional 28 manual grab samples were collected to represent time series from five distinct runoff events. Sampling efficiency was checked by comparing collected volumes with the theoretical ones (derived from pump mileage data). Ranges and ratios of concentrations measured from composite and grab samples were graphically interpreted in order to evaluate their representativeness. It has been shown that the concept is suitable for conducting cost-effective urban runoff characterization surveys targeting inter-event variability.

No abstract

A junction structure of the greatest combined sewers of Budapest (Hungary) was under hydrodynamic and water quality examinations. The selected junction performs an important role in the operation of a combined sewer overflow. The main environmental effects are on the receiving water body, on the biggest main sewer and on the wastewater treatment plant. In the first step, one-dimensional hydrodynamic simulation was executed for the main and lateral inflow sewers. The simulation results were presenting the open surface elevations of the water flow. In the next step, a 3D fluid flow model was built based on a steady state simulated flow assumption. The resulting velocity and turbulence distribution were showing the critical points of the structure and the joining conduits. The simulation without the lateral inflow highlighted the negative effect of the lateral inflow. The high velocity of the inflowing water is forcing the main branch flow to slow down. The water level and the sedimentation are increasing upstream in the main sewer. Historical sediment volumes data and frequent flooding complaints are confirming the simulation results. Suggestions based on 3D model simulations are given for the improvements.

No abstract

No abstract