This study assessed the effectiveness of integrating electrocoagulation, magnetic fields, and ozonation technologies to remove chemical oxygen demand (COD) and total suspended solids (TSS) from tannery wastewater. Furthermore, the effects of their key operating factors were determined. To achieve this goal, an electrocoagulation reactor coupled with a magnetic-field generator was used and the response surface methodology was applied through a Box-Behnken experimental design. Here, current intensity (I), treatment time (T), and ozone concentration (O3) are considered the influencing factors. Likewise, the removal percentages of COD and TSS serve as response indicators. The results indicate that T, I, and O3 are significant for the removal of COD and TSS at a confidence level of p-value < 0.05. For COD, the optimal operating conditions are I = 6.8 A, T = 30 min, and O3 = 10 mg/l; and for TSS, the optimal conditions are I = 5.72 A, T = 28 min, and O3 = 7.8 mg/l. These conditions yield removal efficiencies of 41.8% for COD and 97.9% for TSS. The findings suggest that integrating these technologies is a viable alternative for mitigating the pollution issues caused by the tannery industry.
Treatment of Municipal wastewater by Electrocoagulation (EC) process using punched aluminium and zinc electrodes was studied in a batch EC cell reactor. Response surface methodology (RSM) based on Central Composite Design (CCD) was utilized to optimize the operating parameters for the removal of % Total Suspended Solids (TSS) and % Chemical Oxygen Demand (COD) from Municipal Sewage. Effect of operating parameters such as Electrode Distance (x1), Electrolysis Time (x2) and Voltage (x3) has been optimized for the removal of TSS and COD. The prediction of removal percentage of TSS and COD in various Operational circumstances is done by using Quadratic model. The significance of each operating parameter was computed by Analysis of variance (ANOVA). To achieve the maximum removal of % TSS and % COD, the optimum conditions were Electrode distance(x1)-3 cm, Electrolysis Time (x2)-70.299 minute and Voltage (x3)-6.5V. It was observed that the performance of electrocoagulation process increased up to 61.45% for COD removal, and 73.73% for TSS removal using punched electrode compared to plane electrodes.
The investigation of spatial changes in phytoplankton biomass and turbidity provide essential information for the survival of the coral reef ecosystem. The phytoplankton biomass variations are driven by many factors, such as nutrient inputs from anthropogenic and natural. In turn, turbidity is determined by sediment resuspension or transport from terrestrial systems. The estimation of phytoplankton biomass is represented by the chlorophyll-a concentration. This study aimed to analyze the chlorophyll-a dynamics to water quality parameters, such as turbidity, suspended solids, dissolved oxygen, pH, salinity and temperature. The in-situ data gathered at 26 stations in the waters of the Barrang Caddi Island in August 2020. The results show that chlorophyll-a and turbidity have a negative correlation in the western and eastern regions, since turbidity inhibits the rate of photosynthesis and causes the decreasing of phytoplankton biomass. Nevertheless, the highest concentration of chlorophyll-a was found in the southern location, in small spots around islands and reefs, including near Barrang Caddi Island. Total Suspended Solid has more significant effect on chlorophyll-a than other water parameters, such as turbidity, temperature, salinity in the study area.
For the purposes of research and this resultant publication, the water quality was tested in three reservoirs differing in operating times. It was assumed that the study period covering autumn, spring and early summer was the period with the most visible changes in the concentrations of pollutants. The samples taken from the reservoirs were analysed by determining biological oxygen demand (BOD5), ammonia concentration (NH4), phosphate concentration (PO4) and total suspended solids. The use of indicators allowed for assessing the quality of water in these reservoirs and comparing it in terms of different periods of their operation. It was also observed that the water flowing into the Roszków and Jeżewo reservoirs (two oldest reservoirs) was of worse quality than the outgoing water. In the case of the newest reservoir, the water quality at the outflow deteriorated in relation to all indicators.
This study aims to optimize the removal of total suspended solids (TSS) in pump water from fish flour factories through electrocoagulation technology and to determine the effects of the main operation parameters. Pump water has high conductivity (40.1 mS), due to the presence of dissolved salts and contains high concentration of organic substances (12,360 mg/L of TSS and 520 mg/L of fats). In this study, pump water was treated in an electrocoagulation reactor with aluminum electrodes using Response Surface Methodology with a 3k factorial design based on two factors, current intensity (I) of 8-13 A and treatment time (t) of 20-40 minutes. The percentage of TSS removed from the water was used as the response variable. The results revealed that I and t significantly (p < 0.05) influenced the process. In accordance, the optimal operational parameters for TSS removal were I = 13 A and t = 30 minutes. Using these conditions, TSS removal efficiency of 99.9% was achieved. The sewage sludge generated with these optimal process conditions indicated 19.3% of ash content, 6.2% of salt, 1.7% of aluminum, 0.3% of iron, 0.4% of potassium, 256 ppm of zinc, and 2.1% of phosphorus. Hence, the results of this study affirm that electrocoagulation can be considered as a solution for marine pollution caused by fishing industries.
The intensive agricultural use of the land affects both quantity and quality of river water in the catchment area. Such impact is visible also in the Szreniawa River catchment in the Małopolskie Voivodeship. The combination of intensive plowing and soil susceptibility to water erosion are the main causes of soil and nutrients depletion during the heavy rainfall. The aim of the study is to determine changes in the water quality in the Szreniawa River catchment compared to the agriculture use and precipitation level. The quality of surface water has been analysed in the river catchment area in three sampling points. The concentration of the total suspended soils in the samples collected after heavy rainfall in August 2017 reached a value of 837 mg·dm–3. The average concentrations of N-NO3 in the years of 2016–2019 ranged from 0.16 to 13.46 mg·dm–3, with the highest values in the summer (up to 13.46 mg·dm–3). The concentration of N-NH4 and P-PO4 in the Szreniawa water was affected by precipitation. The highest value of average concentration of N-NH4 3.00 mg·dm–3 was recorded in the autumn of 2019 in the middle section of the river. The highest value of P-PO4 0.90 mg·dm–3 was recorded in the autumn of 2019 mostly due to water erosion of the loess areas. Erosion has been caused by the short-term heavy rainfall. As a result, suspended solids, soluble and insoluble phosphorus compounds leaked to the river.
Since the 1990s, there have been trends in Central and Eastern European countries to reduce water consumption. This phenomenon is closely related to the political, social and economic changes in these countries and the introduction of economic instruments in water management. The article presents the changes in water consumption in households in the years 1950–2019 depending on the degree of equipping buildings with sanitary facilities, and the structure of water consumption for particular purposes. For the same period, the quality of sewage generated in households is presented on the basis of bibliography. The content of total suspended solids was the main analysed parameter. The last part of the article presents the quality of wastewater discharged to fourteen Polish wastewater treatment plants. The majority of the analysed plants show an increase in the concentration of total suspended solids in the domestic sewage discharged to them. This phenomenon may be influenced by the decreasing water consumption in households.
Jednym z podstawowych składników ścieków komunalnych są zanieczyszczenia organiczne, których zawartość jest określana najczęściej na postawie ich biochemicznego zapotrzebowania na tlen (BZT5). W artykule opracowano prosty model regresyjny do szacowania wartości BZT5 ścieków komunalnych w celu zapewnienia bieżącej kontroli sprawności procesu biologicznego oczyszczania oraz możliwości optymalizacji warunków eksploatacji reaktorów biologicznych. Model opracowano na podstawie danych pochodzących z wieloletniego (1990–2000) monitoringu jakości ścieków w oczyszczalni Terrence J. O’Brien Water Reclamation Plant w Chicago (USA). Analizie statystycznej poddano wartości następujących wskaźników jakości ścieków dopływających do oczyszczalni: pH, BZT5, zawiesiny ogólne, azot amonowy, azot Kjeldahla oraz azotany. Wszystkie obliczenia wykonano w programie statystycznym R z nakładką R Studio w wersji 1.0.143. Do wyboru parametrów istotnych do budowy modelu zastosowano kryterium informacyjne Akaikego (AIC) oraz algorytm Leaps. Na podstawie wyników testowania sformułowano model regresyjny do szacowania wartości BZT5 ścieków komunalnych wykorzystujący zawartości zawiesin ogólnych oraz azotu Kjeldahla i azotanów w ściekach. Algorytm formułowania modelu regresyjnego, przydatnego do szybkiego uzyskiwania przybliżonych wartości BZT5 ścieków, może posłużyć do budowy podobnych modeli na potrzeby innych oczyszczalni ścieków, bez konieczności częstego wykonywania oznaczeń laboratoryjnych i długiego oczekiwania na ich wyniki.
EN
One of the primary components of municipal sewage is organic pollution, the content of which is determined most often on the basis of its biochemical oxygen demand (BOD5). In the paper, a simple regression model was developed to estimate BOD5 values of municipal sewage in order to ensure ongoing effi ciency control of the biological treatment process and possibilities for optimizing the operating conditions of biological reactors. The model was developed from the long-term monitoring data (1990–2000) on wastewater quality in the Terrence J. O’Brien Water Reclamation Plant in Chicago (USA). Statistical analysis covered the following quality indicators for the sewage material fl owing into the treatment plant: pH, BOD5, total suspended solids, ammonium nitrogen, Kjeldahl nitrogen and nitrates. All calculations were made using a statistical program R with R Studio patch, version 1.0.143. Akaiki Information Criterion (AIC) and the Leaps algorithm were employed to select parameters relevant to constructing the model. Based on the results of model testing, the regression model for BOD5 values estimation in municipal wastewaters was formulated. The model employed parameters such as total suspended solids, Kjeldahl nitrogen and nitrates wastewater content. The algorithm of formulating the regression model that allows for quick generation of approximate BOD5 values in wastewater can be applied to development of similar models for other treatment plants, with no need for frequent laboratory testing and long wait for the results.
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W niniejszym artykule przedstawiono wyniki badań wybranych wskaźników zanieczyszczeń odcieku z odwadniania osadów ściekowych poddanych procesowi kondycjonowania falami ultradźwiękowymi. Wskaźnikami, na które zwrócono szczególną uwagę są związki biogenne (azot Kjeldahla i fosfor ogólny) oraz ogólny węgiel organiczny i zawiesina ogólna.
EN
This article presents the results of research on selected indicators of effluent from sewage sludge dewatering after applying on them the conditioning process using ultrasonic waves. The discussed indicators are biogenic compounds (Kjeldahl nitrogen and total phosphorus) and total organic carbon and total suspended solids.
Do lokalnego zbierania i zagospodarowania wód opadowych często wykorzystuje się powierzchnie dachów. Dzieje się tak dlatego, że stanowią one duży udział powierzchni uszczelnionych w miastach, a spływy z nich są traktowane jako potencjalnie czyste. Wyniki licznych badań naukowych dowodzą jednak, że dachy są miejscem gromadzenia zanieczyszczeń, które mają wpływ na jakość odprowadzanych wód. Najliczniejszą grupę zanieczyszczeń występujących w spływach stanowią zawiesiny. To od ich stężenia, a niekiedy także wielkości cząstek uwarunkowany jest dobór urządzeń służących do podczyszczania wody deszczowej, a w kolejnym etapie możliwości dalszego jej wykorzystania. W artykule przedstawiono wyniki badań spływów odprowadzanych z dachów wykonanych z materiałów tradycyjnych oraz z zielonych dachów, zlokalizowanych na terenach zurbanizowanych. Oceny dokonano w zakresie ilości i wielkości cząstek zawiesin w odniesieniu do charakterystyki opadów, tj. wielkości opadów i długości okresów bezopadowych oraz pór roku. Wyniki badań wykazują zróżnicowanie stężeń i wielkości zawiesin w odpływach w zależności od pokrycia dachu, charakterystyki opadów i sezonu. Najwyższe stężenia zawiesiny w odpływach z dachów tradycyjnych obserwowano w czasie opadów o wysokości mniejszej niż 5 mm na dobę, po okresie bezopadowym trwającym dłużej niż 50 h oraz w zimie. Parametry te nie wywierały większego wpływu na niskie stężenia zawiesin występujących w spływach z zielonych dachów. Największy udział w spływach ze wszystkich analizowanych dachów stanowiły cząstki zawiesin o wielkości do 200 μm.
EN
Among various drainage surfaces which allow rainwater to be utilised locally, roofs are frequently chosen solution. This is because they represent a big share of all sealed surfaces in cities and discharged liquids are considered potentially clean. Scientific reports confirm that pollutants accumulate on roofs and influence the quality of discharged water. Suspended solids are the biggest group of pollutants which occur in runoffs. The selection of rainwater pre-treatment installation and further use of the water depends on the concentration of suspended solids and their particle size. This article describes results of a research concerning suspended solids discharged from roofs made of traditional materials as well as green-roofs located in urban areas. The quantity and size of particles were assessed against rainfall characteristics: rainfall depth, length of antecedent dry weather periods and season. Results of the research show diversity of concentration levels and size of suspended solids within runoffs in reference to roofing materials, rainfall characteristics and season. The highest concentrations of suspended solids in runoff from traditional roofs were observed during rainfall depth less than 5 mm, after ancedent dry weather periods more than 50 h and in winter. These parameters did not have significantly influence on the low concentrations of suspended solids in runoff from green roofs. Suspended solids particles with the size of up to 200 μm constitute the biggest share of all roof runoffs.
The reliability of removal of selected contaminants in three technological solutions of the household sewage treatment plants was analysed in this paper. The reliability of the sewage treatment plant with activated sludge, sprinkled biological deposit and hybrid reactor (activated sludge and immersed trickling filter) was analyzed. The analysis was performed using the Weibull method for basic indicators of impurities, BOD5, COD and total suspended solids. The technological reliability of the active sludge treatment plant was 70% for BOD5, 87% for COD and 66% for total suspended solids. In the sewage treatment plant with a biological deposit, the reliability values determined were: 30% (BOD5), 60% (COD) and 67% (total suspended solids). In a treatment plant with a hybrid reactor, 30% of the BOD5 and COD limit values were exceeded, while 30% of the total suspended solids were exceeded. The reliability levels are significantly lower than the acceptable levels proposed in the literature, which means that the wastewater discharged from the analysed wastewater treatment plants often exceeds the limit values of indicators specified in currently valid in Poland Regulation of the Minister of Environment for object to 2000 population equivalent.
PL
W pracy przeanalizowano niezawodność usuwania wybranych zanieczyszczeń w trzech rozwiązaniach technologicznych przydomowych oczyszczalni ścieków: oczyszczalni z osadem czynnym, ze złożem biologicznym zraszanym oraz reaktorem hybrydowym (osad czynny i złoże biologiczne zanurzone). Analizę wykonano z wykorzystaniem metody Weibula w odniesieniu do podstawowych wskaźników zanieczyszczeń: BZT5, ChZT i zawiesiny ogólnej. Niezawodność technologiczna oczyszczalni z osadem czynnym kształtowała się na poziomie 70% w przypadku BZT5, 87% – ChZT i 66% – zawiesiny ogólnej. W oczyszczalni ścieków ze złożem biologicznym zraszanym wyznaczone wartości niezawodności wyniosły: 30% (BZT5), 60% (ChZT) i 67% (zawiesina ogólna). W oczyszczalni z reaktorem hybrydowym przekroczenie dopuszczalnej wartości BZT5 i ChZT miało miejsce w 30% przypadków, a zawiesiny ogólnej w 28%. Wyznaczone poziomy niezawodności są wyraźnie niższe od poziomów dopuszczalnych proponowanych w literaturze, co oznacza, że w ściekach oczyszczonych odpływających z analizowanych oczyszczalni często pojawiają się przekroczenia wartości granicznych wskaźników, określonych w aktualnie obowiązującym Rozporządzeniu Ministra Środowiska dla obiektów o wielkości poniżej 2000 RLM.
Prognoza jakości i ilości ścieków deszczowych oraz osadów ściekowych jest bardzo złożona ze względu na stochastyczny charakter zjawisk opadowych oraz procesów gromadzenia i zmywania zanieczyszczeń deponowanych na powierzchni zlewni. Ma to szczególnie duże znaczenie w projektowaniu ciągów technologicznych oczyszczalni wód deszczowych (OWD), gdzie przyjęcie błędnych założeń na etapie obliczeń może doprowadzić do nieprawidłowego funkcjonowania poszczególnych obiektów i urządzeń. Przedstawiona w artykule wstępna ocena funkcjonowania oczyszczalni wód deszczowych przy ul. Witosa w Kielcach, do której dopływają ścieki głównie z terenu pod zabudową jedno- i wielorodzinną, stanowi pierwszy etap badań, mających na celu stworzenie modelu matematycznego analizowanego fragmentu sieci kanalizacyjnej. Model numeryczny oczyszczalni wód deszczowych (OWD) wykonano w programie SWMM (ang. Storm Water Management Model) na podstawie dokumentacji projektowej obiektu oraz wizji terenowej, natomiast model hydrodynamiczny zlewni wraz z siecią kanalizacji deszczowej – na podstawie map topograficznych i zasadniczych. Do obliczeń średniego jednostkowego natężenia deszczu (q) wykorzystano 33 zdarzenia opadowe zarejestrowane w latach 2010–2011, podczas których czas trwania deszczu i wysokość warstwy opadu zmieniały się odpowiednio w zakresach td = 12–1244 min oraz P = 1,8–44,6 mm. Przeprowadzone symulacje działania OWD wykazały, że gdy średnie jednostkowe natężenie deszczu przyjmowało wartości poniżej 10 dm3∙(ha∙s)-1, stopień redukcji zawiesin ogólnych (η) w osadniku zmieniał się w granicach 0,78–0,98, a gdy q = 10–75 dm-1∙(ha∙s), to η = 0,69–0,88. Wykonane w pracy obliczenia mają charakter wyłącznie szacunkowy, ponieważ model nie został skalibrowany na podstawie rzeczywistych wartości natężenia przepływu ścieków deszczowych oraz stężenia zawiesin ogólnych.
EN
Due to the stochastic character of precipitation phenomena combined with an accumulation of pollutants in the catchment area and their wash-off, the prediction of stormwater quantity and quality, its sediments is very complex. It is especially important when designing the stormwater treatment plant’s (STP) stages of technological lines, because there can be massive calculation errors at selection and functions of particular objects and equipment. The preliminary evaluation, of stormwater treatment plant in Witosa St., Kielce shown in the above article, where stormwater runs off mainly from housing estates of single and multi-family houses, is the first stage of researches concerning preparation of the mathematical model of analysed part of a sewer system. The numerical model STP was made by SWMM software and was based on the working plans of the object and field studies, whereas the hydrodynamic modelling with stormwater drainage system were made according to topographic and basics maps. 33 rainfall events were used to measure the amount of average rainfall intensity. They were registered between 2010 and 2011. During that time the rainfall duration and depth of precipitation changed as follows: td = 12–1244 min and P = 1.8– 44.6 mm. The simulations done by STP shown that in case of average rainfall intensity below 10 dm3∙(ha∙s)-1 the reduction of TSS (η) in a catch basin would change into 0,78–0,98, for q = 10–75 dm3∙(ha∙s)-1, the result was η = 0,69–0,88. The calculations carried out at work are only approximate, because the model was not calibrated on the basis of the actual value of the stormwater flow, the rainfall amount and total suspended solids concentrations.
The paper presents the results of snow contamination collected from roadsides and parks of Czestochowa in these areas which are out of the impact of a transport. The study was conducted within 2009–2011, in which 120 samples were tested in general. In snowmelt and rain waters that are brought to the sewer or land there are the following pollutants such as: suspended solids, hydrocarbons, heavy metals, biogenic compounds, and even bacteriological contamination. The scope of the research included: pH, total suspended solids, COD and heavy metals in waste water coming into the sewer. On the basis of the survey and analysis of the literature data it is possible to admit the high variation in pollutant concentrations in snow cover, mainly related to the place of sampling. It should also be noted that the other factors, such as: the length of snow cover, the outside temperature, the duration of test runs, the direction of the winds, in the case of the particular type of a substance thawing roads, have affected the results of measurements substantially as evidenced by their differentiation to the point for further measurements. The samples of snow from the sides of roads and parking areas have been characterized by a high content of suspended solids falling within the broad range from 165 to 1325 mg/dm3, COD values ranged from 89.0 to 825.0 mg O2/dm3. The pH of the snow stood at the level of 4.75–6.50. The analysis of the results has shown that the vast majority of the samples has been characterized by a natural or light acidity. The pH value was associated with a place and time of sampling. Most of the snow samples, collected from roadsides with heavy traffic and parking spaces, pointed to their acidic or slightly acidic character. The average content of heavy metals: Cd, Pb, Zn, Cu and Ni within the snow was generally low, which could be due to the fact that the tests were performed within metals concentration in water after the filtration of a suspension. It should be pointed out, however, that the snow from these areas that are exposed to the direct impact of transport, contained more metals for several times, compared with the periphery of busy roads or parking lots. On this basis it can be concluded that the main source of pollution of snow cover was, as analyzed, the catchment traffic, much less air pollution from the other sources. Therefore, the concentration of pollutants in snow cover areas directly adjacent to roads and parking spaces, due to the high concentration of pollutions, ought to be monitored. It should be paid attention to the need to standardize the procedures within sampling the snow.
W artykule dokonano analizy efektywności pracy oczyszczalni ścieków w Kołaczycach na podstawie wyników badań fizykochemicznych ścieków surowych oraz ścieków oczyszczonych w latach 2010 – 2014. Przeanalizowano zmiany wartości trzech wskaźników zanieczyszczeń – BZT5, ChZTCr i zawiesiny ogólnej. Wyniki badań wskazują na to, iż oczyszczalnia funkcjonuje w sposób prawidłowy. Średnia wartość BZT5 w ściekach oczyszczonych wyniosła 10,9 mg O2 dm-3, ChZTCr – 71,0 mg O2 dm-3, zawiesiny ogólnej – 15,0 mgdm-3, a zatem wielkości te były mniejsze od dopuszczalnych wartości w ściekach odprowadzanych do odbiornika, które reguluje Rozporządzenie Ministra Środowiska z 2014 roku. O zadowalającej efektywności pracy obiektu świadczy również wysoka procentowa średnia redukcja każdego ze wskaźników zanieczyszczeń (dla BZT5 – 97,8%, dla ChZTCr – 93,7%, dla zawiesiny ogólnej – 97,6%), a także wartości współczynników niezawodności oczyszczalni (WNBZT5= 0,44, WNChZTCr= 0,57, WNzaw.og.= 0,43).
EN
In the article the analysis of operational efficiency Wastewater Treatment Plant in Kolaczyce was performed based on the physico-chemical research results of raw sewage and treated sewage between 2010 and 2014. The analysis of values changing of three pollutants indicators – BOD5, CODCr and total suspended solids was performed. Research results indicate that treatment plant works properly. Average value of BOD5 in treated sewage was 10.9 mg O2 dm-3, CODCr – 71.0 mg O2 dm-3, total suspended solids – 15.0 mg dm-3 so these values were lower than permissible pollutants content in sewage discharged to the collector which is determined by the Polish Ministry of Environmental Regulation of 2014. On satisfactory operational efficiency treatment plant indicates also high percentage reduction of each pollutants indicators (for BOD5 – 97.8%, for ChZTCr – 93.7%, for total suspended solids – 97.6%) and treatment plant reliability factors (WNBZT5= 0.44, WNChZTCr= 0.57, WNzaw.og.= 0.43).
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