Efficiency of heavy metals removal during roof runoff infiltration through vegetated soil

Stormwater discharged from urban areas can contain significant amounts of heavy metals, especially zinc and copper. Roof runoff is very often directed into the soil and may pose a risk for groundwater quality. Lysimeter research has shown that zinc and copper contained in stormwater may be effectively removed by passing through vegetated soil. The average removal efficiency was greater than 90% and did not depend on the metal concentration in the influent, and the concentrations in the effluent met the limits for drinking water. Infiltration may be a reliable treatment method for roof runoff and may make stormwater safe for groundwater recharge

Zielona infrastruktura w małych miastach jako element zrównoważonej gospodarki wodami opadowymi

The possibilities of local stormwater management with the use of vegetation were discussed. These solutions are an element of green infrastructure in urban areas and contribute, among others, to improve local hydrological conditions and microclimate, to increase the aesthetics and attractiveness of urban space, and in conditions of climate change may improve the safety of the city's functioning during intense rainfall.W artykule przedstawiono możliwości lokalnego zagospodarowania wód opadowych z wykorzystaniem roślinności. Rozwiązania te stanowią element zielonej infrastruktury na obszarach zurbanizowanych i przyczyniają się m.in. do poprawy lokalnych warunków hydrologicznych i mikroklimatu, podniesienia estetyki i wzrostu atrakcyjności przestrzeni miejskiej, a w warunkach zmian klimatu mogą poprawiać bezpieczeństwo funkcjonowania miasta w czasie intensywnych opadów

The selection of the method for sewerage system modernisation employing the ahp method of multicriterail optimization

Modernizacja systemów kanalizacyjnych wymaga uwzględnienia różnych wariantów rozwiązań. Dotychczas są one oceniane zazwyczaj według jednego kryterium, najczęściej ekonomicznego. Pełna ocena takich zamierzeń wymaga natomiast uwzględnienia także kryteriów pozaekonomicznych, na przykład społecznych i niezawodnościowych. Ocenę taką umożliwia między innymi metoda AHP (Analitical Hierarchy Process), w której mogą być ujęte rozmaite kryteria mierzalne i niemierzalne, wartościowane względem siebie. W artykule przedstawiono ogólne zasady stosowania metody AHP oraz przykład jej zastosowania do wyboru optymalnego wariantu modernizacji systemu kanalizacyjnego dla rzeczywistej zlewni.In the paper, we demonstrate the example of the use of Analytic Hierachy Process (AHP) for searching an optimal solution of an urban sewerage system modernization. The principles of the AHP method and its applicability for environmental projects are presented. The fi ve following criteria of solution assessment were taken into consideration: economic, ecological, reliability, social and technical. The aim of modernization of the sewerage system was reducing environmental impact due to CSO events, hydraulic relief of conduits and in consequence reducing of fl ooding on urban catchment. Four alternatives of meeting this aim were analysed: one storage tank prior to the CSO, eight storage tanks located on the catchment, one storage tank on the CSO channel, dispersed retention devices located on the sub-catchments. The alternative no.1 was found as the optimal solution of the problem

Assessment of total suspended solid emission discharged via storm sewerage system from urban areas

Total suspended solid (TSS) input into receiving waters is an important pollutant adversely influencing aquatic environment and condition of aquatic biota. The main sources of total suspended solids are processes of soil erosion and washing out of solid matter by storm runoff, particularly from urban catchments. Quality of stormwater runoff essentially depends on rainfall duration and intensity, pollutant accumulation on the catchment as well as duration of dry weather period prior to the rainfall event. The frequency and levels of total suspended solid concentration in stormwater discharged from a real urban catchment were determined using SWMM (Storm Water Management Model) software. The SWMM model has been calibrated based on the rainfall, receiving water flow rate and TSS concentration data obtained for that catchment. For more than one third of precipitation events TSS mean concentration was found to exceed 100 g/m3. Such level of pollution may be critical for ecosystems of small urban rivers. The results of presented analyses prove that quality monitoring as well as stormwater treatment should be introduced for stormwater discharges in urban catchments.Zawiesiny ogólne wprowadzane do odbiorników wodnych są ważnym zanieczyszczeniem negatywnie wpływającym na środowisko wodne i kondycję organizmów wodnych. Głównymi źródłami zawiesin ogólnych są procesy erozji i spłukiwania zanieczyszczeń stałych, szczególnie ze zlewni miejskich. Skład ścieków deszczowych zależy przede wszystkim od czasu trwania i intensywności opadów atmosferycznych, akumulacji zanieczyszczeń na powierzchni zlewni oraz czasu trwania tzw. suchej pogody przed deszczem. Wykorzystując program SWMM określono częstość i zawartość zawiesin ogólnych w ściekach deszczowych odprowadzanych z rzeczywistej zlewni miejskiej. Model SWMM został skalibrowany na podstawie danych dotyczących opadów atmosferycznych, strumienia objętości wody w odbiorniku oraz zawartości zawiesin w zlewni. Stwierdzono, że w przypadku ponad jednej trzeciej opadów atmosferycznych, średnia zawartość zawiesin ogólnych przekraczała 100 g/m3. Taka zawartość zanieczyszczenia może być groźna w przypadku ekosystemów małych rzek miejskich. Otrzymane wyniki dowodzą, że w zlewniach miejskich powinien być prowadzony zarówno monitoring ścieków deszczowych, jak i ich oczyszczanie

Prospects for reduction of the impact of wastewater discharge from urban areas on surface water quality in view of legal regulations

Despite full adoption of EU requirements into current legal regulations in Poland, surface waters as sewage receivers in urban areas still cannot be considered fully protected, especially against contamination from sewer overflows and storm water systems. The examples discussed demonstrate that urban wastewater discharged from sewer overflows and storm water systems during rainfalls has a clearly dominant share in the load of pollutants emitted to the receiver. It is therefore important to develop efficient tools of water protection against these contaminants. Uniform but rather limited provisions applicable throughout the country do not take account of specific local conditions, especially size of wastewater receivers and size and characteristics of the catchment area, preventing therefore effective and economically viable water protection. The results of this research, carried out in Lodz, examining pollution loads discharged from the urban catchment area, illustrate that current approach to surface water protection issues requires a revision. Feasibility of regulatory changes in the area of setting requirements for effective receiver protection against pollutants discharged from urban areas was presented, considering the impact of untreated wastewater on the receiving water. It is also necessary to take comprehensive measures both in terms of research on pollutant emissions and their impact on the receiver and the method to utilize the results of such studies. This would enable more widespread use of urban wastewater discharge system modeling, which in turn would enable a reliable assessment of their impact on the receiver and taking appropriate modernization decisions. All of these activities are preconditions for sustainable rainwater management in urban areas

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