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1

Contaminants Removal from Real Refinery Wastewater Associated with Energy Generation in Microbial Fuel Cell

Jabbar Noor Mohsen, Alardhi Saja Mohsen, Al-Jadir Thaer, Dhahad Hayder Abed

Journal of Ecological Engineering

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2023

|

Vol. 24, nr 1

107--114

EN

Microbial fuel cells (MFCs) pertain to a kind of modern technology for the direct conversion of chemical energy in organic matter from wastewaters into electricity during the oxidation of organic substrates. A system of continuous MFC was constructed for the treatment of real petroleum refinery wastewater (PRW). The treatment of real PRW, operational performance of the MFC system, biodegradation of furfural, and energy output were investigated in this study. The MFC was inoculated by mixed anaerobic bacteria, with Bacillus sp. as the dominant type, and continuously operated for 30 days. The biodegradation of furfural and phenol, which are the most prevalent toxicants in refinery wastewater, was investigated. The MFC system reached maximum energy outputs of 552.25 mW/m3 and 235 mV. In the anodic chamber, the maximum removal of furfural and phenol was higher than 99%, with biodegradation of organic content reaching up to 95%. This study demonstrated the viability of a continuous-flow MFC system as a green technology for the treatment of furfural-rich real refinery effluents while generating electricity.

2

Reduction of Contaminants from Municipal Wastewater of Salori Sewage Treatment Plant Using Electrochemical Membrane Bioreactor and Bioelectricity Generation

Yadav Saurabh, Kamsonlian Suantak, Gola Deepak, Pal Shubham

Ecological Engineering & Environmental Technology

|

2023

|

Vol. 24, iss. 1

264--271

EN

Membrane bioreactor (MBR) is stable and rising wastewater treatment reactor though membrane fouling and energy expenditure remain operational impediments and challenges for the wider deployment of the MBR technology. The majority of municipal wastewater contains low quantities of suspended, dissolved inorganic and organic particles. Proteins, carbohydrates, synthetic detergents, lignin, soaps, lipids and their decomposition products, along with many natural and synthetic organic chemicals from industrial processes, are also examples of impurities present in water. In addition, municipal wastewater contains a variety of inorganic chemicals, such as heavy metals, which might have phytotoxic and health consequences, limiting its usage in agriculture. In this study, an electrochemical membrane bioreactor (EMBR) has been developed to reduce several impurities from real municipal wastewater; moreover bioelectricity was also generated simultaneously. The maximum removal of biological oxygen demand (BOD), chemical oxygen demand (COD) and total dissolved solid (TDS) were 35.57%, 31.55%, and 32.84 %, respectively, after a 5-day experimental run.

3

Modelling process of municipal wastewater quality - backgrounds and preliminary application

Bogalecka Magdalena, Dereszewska Alina

Safety and Reliability of Systems and Processes

|

2022

|

Summer Safety and Reliability Seminar 2022

17--34

EN

The probabilistic model of municipal wastewater quality process is proposed in the chapter. The methods of its characteristics and parameters statistical identification and prediction are presented. Next the proposed model is practically applied to examine and characterized the quality of the municipal wastewater collected in the exemplary sewage treatment plant.

4

Treatment of wastewater from the production of meat and bone meal by the Fenton process and coagulation

Makara Agnieszka, Kowalski Zygmunt, Radomski Piotr, Olczak Piotr

Polish Journal of Chemical Technology

|

2022

|

Vol. 24, nr 4

51--60

EN

Wastewater from the production of meat and bone meal, due to the high load of organic matter and suspended solids, is a significant problem in the process of its treatment. In this work, we examined the method of treating this wastewater using coagulation with hydrogen peroxide and the Fenton process. Treatment variants included the use of variable Fe2+/H2O2 ratios of 1:5–1:30, variable doses of 3–18.0 g/L H2O2, and 5–10 mL/L of coagulant PIX 113. The calculated reduction degrees showed that, regardless of the treatment variant used, the greatest reduction was obtained for turbidity (100%), phosphorus (99%), followed by color (97%), chemical oxygen demand (70%), and Kjeldahl nitrogen (48%). The proposed treatment options can be used as a preliminary stage in treating wastewater from the production of meat and bone meal.

5

FE2(SO4)3 and Bentonite Use to Reduce Cod Indicators in Wastewater Containing Detergents

Issayeva Akmaral, Abubakirova Azhar, Syzdykova Marzhan, Arystanova Saltanat, Anlamasova Gulnara, Zhumakhanova Roza, Leska Boguslawa

Journal of Ecological Engineering

|

2022

|

Vol. 23, nr 3

68--73

EN

Wastewater pollution with detergents is one of the environmental problems associated with the rational use of water resources. The existing methods of physicochemical wastewater treatment, despite their efficiency, are open to secondary environmental pollution. Biological coagulation/flocculation methods are widely used with the plant waste. The aim of this research was the use of ferric iron obtained by means of the bacterial-chemical method and bentonite to reduce the chemical oxygen demand in the wastewater containing detergents. It was identified that the use of Fe2 (SO4)3 obtained using the bacterial-chemical method with thionic bacteria Acidithiobacillus ferrooxidans BIT 1 and bentonite as a clay material is promising. At the same time, it was found that the highest reduction degree in the chemical oxygen demand – 88.1 ± 7.9% in wastewater was noted in the variation where the bacterial-chemical ferric iron in the amount of 1.75 g/L was used in combination with bentonite in the amount of 600 mg/L.

6

Annual Variation in the Performance of Settat Wastewater Stabilization Ponds Located in Settat City, Morocco

Dyaa Abou-Tammame, Jihane Fathi, Abdelhamid Bouzidi

Journal of Ecological Engineering

|

2021

|

Vol. 22, nr 8

153--164

EN

The wastewater treatment plant of Settat city uses the natural lagooning technology, which requires low maintenance cost and little technical expertise. The purpose of this study was to evaluate the stability of plant performance during two years of operation (2019 and 2020), as well as the safety of its treated wastewater for reuse in agricultural irrigation. The results of this study show that the biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and suspended solids (SS) did not exceed the Moroccan standards for discharge. They also show a good stable pollutant load reduction with a mean of 86.44%, 86.89% and 74.61%, for BOD5, COD and SS, respectively. On the other hand, microbiological characterization classifies the treated wastewater as "B" quality water, because the fecal coliform numbers exceed the requirement for "A" quality (1000 CFU/100 ml).

7

Wastewater Treatment Methods for Effluents from the Confectionery Industry – an Overview

Zajda Magdalena, Aleksander-Kwaterczak Urszula

Journal of Ecological Engineering

|

2019

|

Vol. 20, nr 9

293--304

EN

Wastewater from the confectionery industry is characterized by daily and seasonal variability of composition and quantity which adversely affects the process of their disposal. Confectionery plants discharge about 300-500 m3 per month of technological wastewater. Sewage from the confectionery industry belongs to biologically degradable. It is characterized by high values of chemical oxygen demand (COD) and biological oxygen demand (BOD). The article reviews various methods used to treat wastewater from the confectionery industry. Attention was paid to the applicability of a particular method, its advantages and disadvantages and the costs of implementation. The technology of industrial wastewater treatment uses both mechanical and physicochemical methods as well as biological ones. Techniques of sewage treatment usually consist of several stages which use different processes. Low-cost materials such as natural minerals, agricultural waste, industrial waste, biosorbents, and others contribute to the improvement of aerobic sewage conditions. The main weakness of typical sewage treatment plants is their large area, high investment, and exploitation costs. Therefore, a good solution may be the use of the membrane biological reactor which combines the classical technique of activated sludge and filtration on micro-filtering membranes.

8

The Analysis of the Amount of Pollutants in Wastewater after Mechanical Treatment in the Aspect of their Susceptibility to Biodegradation in the Treatment Plant in Nowy Targ

Nowobilska-Majewska Elwira, Bugajski Piotr

Journal of Ecological Engineering

|

2019

|

Vol. 20, nr 8

135--143

EN

The aim of this study was to determine the biodegradability of organic and biogenic contaminants in wastewater flowing into biological reactors in the treatment plant in Nowy Targ. The research period covered the years 2016 and 2017, when 87 samples of raw wastewater and 87 samples of wastewater after mechanical treatment were collected and subjected to physico-chemical analysis. In both types of wastewater, the size of the following indicators was analyzed: BOD5, COD, total kjeldahl nitrogen (TN) and total phosphorus (TP). The study verified the amount of pollutants in the raw wastewater in order to determine whether they are household wastewater. In the next stage of the analysis, the characteristic values of the analyzed indicators in wastewater after the mechanical treatment process were determined in order to indicate mutual dependences of organic and biogenic indicators. Based on the analysis, it was found that wastewater after mechanical treatment (in the case of its susceptibility to biological decomposition processes of organic pollutants) has an unfavorable COD/BOD5 ratio. With regard to the susceptibility of wastewater to nitrification, denitrification and dephosphatation processes, in the majority of cases, wastewater is susceptible to these processes. It is recommended to apply an additional source of organic carbon to wastewater prior to biological treatment in order to improve the biodegradation of the analyzed pollutants.

9

Study of catalytic processes for biodiesel production wastewater treatment

Borralho Teresa, Coelho Solange, Estrelo Andreia

Archives of Environmental Protection

|

2019

|

Vol. 45, no. 2

66--72

EN

The study of the possibility of removing organic compounds from wastewater originating from the biodiesel purification stage by two catalytic processes, HSO5-/transition metal and Fenton method has been presented. The source of the ion HSO5-is potassium monopersulphate (2KHSO5∙KHSO4∙K5SO4) (Oxone) that may be decomposed into radicals (OH., SO4-., SO5-.) by means of transition metal as Co(II). Different concentrations were used for both compounds and the combination ([Co2+] = 1.00μM/[HSO5-] = 5.00·10-2 M) achieved the highest COD removal (60%) and complete decomposition of the oxidant was verified for contact times of 45 min. This process has some advantages comparing to the conventional Fenton method such as the absence of the costly pH adjustment and the Fe(III) hydroxide sludge which characterize this treatment process. The Fenton process showed that the combination of [H2O2] = 2.00M/[Fe2+] = 0.70 M was the best and archived COD removal of 80%. The treatments studied in this research have achieved high COD removal, but the wastewater from the biodiesel purification stage presents very high parametric values of Chemical Oxygen Demand (667,000 mgO2/L), so the final COD concentration reached is still above the emission limit of discharge in surface water, according the Portuguese Law (Decree-Law 236/98). However, both treatments have proved to be feasible techniques for the pre-oxidation of the wastewater under study and can be considered as a suitable pre-treatment for this type of wastewaters. A rough economic analysis of both processes was, also, made.

10

Predictive Modelling for Characterisation of Organics in Pit Latrine Sludge from Unplanned Settlements in Cities of Malawi

Kalulu K., Thole B., Mkandawire T., Kululanga G.

Journal of Ecological Engineering

|

2018

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Vol. 19, nr 3

141--145

EN

The limited availability of data on faecal sludge characteristics remains one of the major challenges faced by developing countries in proper management of faecal sludge. In view of the limited financial resources and expertise in these developing countries, there is a need to come up with less-resource-intensive approaches for faecal sludge characterisation. Despite being used substantially in wastewater, there is limited evidence on the use of predictive modelling as a tool for cost-effective characterisation of faecal sludge. In this study, first order multiple linear regression modelling is investigated as a less-resource-intensive approach for accurate prediction of organics (biochemical oxygen demand and chemical oxygen demand) in pit latrine sludge. The predictor variables explored in the modelling include pH, electrical conductivity, total solids, total volatile solids, fixed solids and moisture content. The modelling uses data collected from 80 latrines in unplanned settlements of four cities in Malawi. The study shows that it is possible to reliably predict chemical oxygen demand and biochemical oxygen demand in pit latrine sludge using electrical conductivity and total solids, which require low levels of resources and expertise to determine.

11

Indirect Electrochemical Oxidation with Multi Carbon Electrodes for Restaurant Wastewater Treatment

Sastrawidana I. D. K., Sukarta I. N.

Journal of Ecological Engineering

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2018

|

Vol. 19, nr 1

200--204

EN

The removal of organic matter from the restaurant wastewater was investigated using the electrochemical oxidation method with multi carbon electrodes in a parallel construction. The degradation process was monitored by the measurement of COD concentration as a function of electrolysis time. The effect of operating parameter conditions on COD removal were investigated including initial pH, distance between electrodes, and the applied voltage difference. The results showed that the treatment of restaurant wastewater containing 2 g/L chloride ion using the electrochemical oxidation technique at the operation conditions characterized by: pH 5, distance between electrode of 10 cm and applied voltage of 12 V, enabled to obtained COD removal of 92.84% within 90 min electrolysis time. It is can be concluded that the indirect electrochemical oxidation method with multi carbon electrodes can be used effectively as an alternative technology for reducing COD and may be potentially applied for removal organic pollutants from wastewater at the industrial scale.

12

Wpływ dezintegracji osadów nadmiernych na zmiany wartości całkowitego węgla organicznego (OWO)

Zawieja I.

Proceedings of ECOpole

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2016

|

Vol. 10, No. 2

785--790

PL

Efektywność przemiany substancji organicznych zawartych w osadach nadmiernych do formy rozpuszczonej jest traktowana jako ważny czynnik limitujący przebieg procesu stabilizacji beztlenowej. Bezpośrednim efektem, zachodzącego w dezintegrowanych osadach, procesu lizy jest wzrost wartości ogólnego węgla organicznego (OWO) oraz korelujący z nim wzrost wartości chemicznego zapotrzebowania na tlen (ChZT) oraz stężenia lotnych kwasów tłuszczowych (LKT). Ogólny węgiel organiczny jest wskaźnikiem zawartości w cieczy nadosadowej całkowitego węgla organicznego w formie rozpuszczonej (RWO) i zawieszonej (ZWO). Wraz z zachodzącym, w wyniku procesów biochemicznych, wzrostem stopniem rozkładu substancji organicznych zawartych w osadach maleje wartość ilorazu ChZT do OWO. Celem badań było określenie wpływu procesu dezintegracji osadów nadmiernych na zmiany wartości całkowitej węgla organicznego. Proces chemicznej dezintegracji osadów nadmiernych prowadzono, stosując wybrane reagenty kwaśne (HCl), zasadowe (KOH) i utleniające (H2O2). Modyfikację przeprowadzono w temperaturze pokojowej w ciągu 6 i 24 godzin. Podczas procesu dezintegracji osadów nadmiernych odnotowano wzrost wartości ogólnego węgla organicznego, chemicznego zapotrzebowania na tlen, a także stężenia lotnych kwasów tłuszczowych, co potwierdziło podatność preparowanych osadów na biodegradację. Stwierdzono, że w przypadku uzyskanego wzrostu wartości badanych wskaźników zastosowany czas preparowania 24 h nie wpłynął znacząco na efektywność dezintegracji prowadzonej wodorotlenkiem potasu. Najwyższą wartość ChZT (8354 mg O2/dm3) uzyskano w przypadku chemicznej dezintegracji wodorotlenkiem potasu w dawce 6 g/dm3 i czasu preparowania 6 h. Dla podanych powyżej warunków preparowania uzyskano wartość ogólnego węgla organicznego 1450 mg C/dm3.

EN

The efficiency of conversion of organic substances contained in the excess sludge to the dissolved form is considered as an important factor limiting the process of anaerobic stabilization. Direct effect, occurring in the disintegrated sludge, lysis process is to increase the value of the total organic carbon (TOC), correlates with the increase of the chemical oxygen demand (COD) and the concentration of volatile fatty acids (VFAs). The total organic carbon content is indicative of the supernatant liquid of total organic carbon in dissolved form (DOC) and suspended (SOC). Together with occurring, as a result of biochemical processes, increase the degree of decomposition of organic substances contained in the sludge decreases the value of the ratio of COD to TOC. The aim of the study was to determine the impact of the process of excess sludge disintegration on the changes of the total organic carbon values. The process of chemical disintegration of excess sludge was treated using the selected acidic i.e. HC, alkaline i.e. KOH, Ca (OH)2 and oxidizing reagents i.e. H2O2. The modification was carried out at ambient temperature for 6 and 12 h. During sludge disintegration it was noticed the growth of total organic carbon values, chemical oxygen demand as well as concentration of volatile fatty acids that confirmed the susceptibility of prepared sludge to biodegradation. It has been found that in the case of the tested indicators, the time of a preparation 24 h did not affect significant the effectiveness of disintegration by KOH. The highest COD value of 8354 mg O2/dm3 obtained in case of chemical disintegration of sodium hydroxide at a dose of 6 g/dm3 and preparation time 6 h. For given conditions of preparing a value of total organic carbon was 1450 mg C/dm3.

13

Efektywność generowania lotnych kwasów tłuszczowych podczas mezofilowej i termofilowej fermentacji metanowej osadów nadmiernych

Zawieja I., Wolny L., Próba M.

Inżynieria Ekologiczna

|

2016

|

Nr 48

226--232

PL

Aktywność mikroorganizmów warunkujących szybkość przemian zachodzących podczas procesu fermentacji metanowej zależy od warunków środowiskowych procesu. Czynnikiem intensyfikującym przebieg fermentacji metanowej jest wzrost temperatury procesu. Prowadzenie procesu fermentacji metanowej w warunkach termofilowych wpływa na szybkości reakcji zachodzących podczas fazy hydrolizy, przyczyniając się do zwiększenia stężenia lotnych kwasów tłuszczowych generowanych z osadów, a w efekcie zwiększenia produkcji biogazu. Należy jednak podkreślić, iż bakterie termofilne wykazują dużą wrażliwość na zmiany temperatury już rzędu ± 0,5°C/d, przy optimum ich wzrostu w zakresie 52–55°C. W związku z tym, aby proces przebiegał optymalnie, bez zakłóceń, konieczne jest zapewnienie stabilnych warunków środowiskowych prowadzących do maksymalnej redukcji substancji organicznych. Podstawowym substratem badań, charakteryzującym się wysoką zawartością związków organicznych i związków azotowych, były osady nadmierne. W celu określenia wpływu fermentacji termofilowej na generowanie lotnych kwasów tłuszczowych osady ściekowe poddano 8-dobowej stabilizacji beztlenowej. Wykonano następujące oznaczenia fizyczno-chemiczne: sucha masa, pH, zasadowość, lotne kwasy tłuszczowe, chemiczne zapotrzebowanie na tlen. W kolejnych dobach procesu, w odniesieniu do fermentacji prowadzonej w warunkach mezofilowych, odnotowano wzrost generowania lotnych kwasów tłuszczowych oraz korelujący z nim wzrost wartości chemicznego zapotrzebowania na tlen. W 8 dobie procesu prowadzonego w warunkach termofilowych stężenie lotnych kwasów tłuszczowych wynosiło 1749 mgCH3COOH/dm3, natomiast wartość chemicznego zapotrzebowania na tlen 3279 mgO2/dm3, przy zasadowości rzędu 3800 mgCaCO3/dm3.

EN

Microbial activity determining the speed of the changes occurring during the process of anaerobic digestion depends on the environmental conditions of the process. The factor intensifying the process of methane fermentation is an increase of temperature. The conducting of the methane fermentation in thermophilic conditions affect the rate of the reactions taking place during the phase of hydrolysis, thus contributing to increase the concentration of volatile fatty acids generated from the sludge, resulting in increasing the production of biogas. It should be noted, however, that thermophilic bacteria have a high sensitivity to temperature changes already the order of ± 0.5 °C/d at their optimum growth in the range of 52–55 °C. Therefore, for the process would run optimally smoothly unnecessary to ensure stable environmental conditions leading to maximum reduction of organic substances. The basic test substrate, characterized by a high content of organic and nitrogen compounds, is excess sludge. To determine the effect of generating the volatile fatty acids during the thermophilic fermentation the sludge was submitted 8-daily anaerobic stabilization. The following designations of physico-chemical characteristics were made: dry matter, pH, alkalinity, volatile fatty acids, the chemical oxygen demand. In the following days of the process operation with regard to fermentation carried out under mesophilic conditions the increase of volatile fatty acids generation was observed, which also correlated with the increase of the chemical oxygen demand. In the 8th day of thermophilic conditions the concentration of volatile fatty acids was 1749 mgCH3COOH/dm3, while the chemical oxygen demand 3279 mgO2/ dm3 and the alkalinity row of 3800 mgCaCO3/dm3.

14

Influence of Ultrasonic Pretreatment on Anaerobic Digestion of Excess Sludge from the Food Industry

Zawieja I., Wolny L., Wolski P.

Rocznik Ochrona Środowiska

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2015

|

Tom 17, cz. 1

351--366

PL

Przeróbka i unieszkodliwianie osadów ściekowych stanowi niezwykle aktualny problem technologiczny, co wiąże się z powstawaniem w ostatnich latach nowych obiektów oczyszczalni, modernizacją już istniejących, jak również z rozwojem wysokoefektywnych metod oczyszczania ścieków. Przez lata wiodącym trendem w zagospodarowaniu osadów ściekowych w Polsce było ich składowanie, jednak obowiązujące w Unii Europejskiej uwarunkowania prawne uniemożliwiają zastosowanie takiego rozwiązania w przyszłości. Modernizacja ciągu technologicznego oczyszczalni ścieków poprzez poprzedzenie wybranych procesów oczyszczania ścieków oraz utylizacji osadów procesem dezintegracji o odpowiednio dobranych parametrach wiąże się ze wzrostem efektywności działania obiektu, nie tylko pod względem technologicznym ale również ekonomicznym. Dezintegracja osadów nadmiernych przed procesem stabilizacji beztlenowej wpływa na zwiększenie podatności osadów na biochemiczny rozkład w warunkach beztlenowych, czego efektem jest przyspieszenie fazy hydrolitycznej procesu, warunkującej powstawanie w kolejnych etapach procesu lotnych kwasów tłuszczowych. Wartość oraz tempo generowania LKT znajduje bezpośrednie odbicie w efektywności produkcji biogazu oraz uzyskanym stopniu mineralizacji osadów. Celem prowadzonych badań była ocena wpływu dezintegracji ultradźwiękowej osadów nadmiernych pochodzących z przemysłu spożywczego na proces hydrolizy będący pierwszym etapem fermentacji metanowej. W badaniach użyto dezintegrator ultradźwiękowy typu VC-750. Osady poddano modyfikacji polem ultradźwiękowym (UD) o amplitudzie drgań pola UD 15, 21, 31, 37, 46 mm i czasie sonifikacji ts = 60–360 s. Następnie przeprowadzono procesy 10-dobowej fermentacji metanowej osadów, poprzedzone modyfikacją osadów nadmiernych polem UD o wybranych, najkorzystniejszych parametrach dezintegracji. Największą skuteczność nadźwiękawiania osadów odnotowano dla czasu ekspozycji równego 360 s oraz amplitudy drgań pola UD 46 mm, uzyskując ok. 5-kotny wzrost wartości ChZT oraz ok. 3-krotny LKT w odniesieniu do wartości początkowych wskaźników.

15

Susceptibility of conditioned excess sewage sludge to biodegradation and dewatering

Wolski P, Zawieja I.

Environment Protection Engineering

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2015

|

Vol. 41, nr 3

5--17

EN

A direct effect of chemical disintegration of excess sludge is an increase in concentration of organic compounds in the sludge liquor, expressed with the levels of soluble chemical oxygen demand (SCOD) and volatile fatty acids (VFAs). The substrate used in the study was activated sludge. The aim of the study was to determine susceptibility of disintegrated excess sludge to biodegradation and dewatering. A SONICS VCX-1500 ultrasonic disintegrator with automated tune-up was used. Thermal disintegration of excess sludge was carried out in water bath with a shaker. Disintegration of excess sludge by the hybrid method was carried out as a combination of the ultrasonic and thermal methods.

16

Biological nutrient removal using a novel five-step continuous flow activated sludge process technology

Abualhai S., Naseer R., Xiwu L.

Environment Protection Engineering

|

2013

|

Vol. 39, nr 3

165--184

EN

An anaerobic-anoxic/oxic (AA/O) five-tank biological process called five-step continuous flow activated sludge process (FSCFASP) was developed to force the oscillation of organic matter and nutrient concentrations in process reactors. The run scheme and schematic diagram of FSCFASP was described. The run cycle was divided into two symmetrical half cycles with eight periods during each cycle. The duration of each period was established according to biological process requirements. The optimal running times of the periods were 90, 60, 60, 30, 90, 60,6 0 and 30 min at the HRT of 16 h, air/water ratio of 35% and SRT of 21 day at the temperature range of 19-23 °C. The optimized system achieved 88.09±1.43%, 90.33±2.9%, 68.83±5.34% and 87.67±2.9% of the chemical oxygen demand, NH4+-N, TN, and TP removal efficiencies, respectively, during a 11-month operation with the effluent meeting the Chinese sewage discharge standard GB18918-2002 (level A). Simultaneous nitrification and denitrification phenomena were observed in the tank one which is important to reduce the quantity of aeration and the duration of a next anoxic state. Compared with other existing technologies, this system achieved high nitrogen and phosphorus removal without equipment of sludge and mixed liquor return. Thus, it is effective for reducing energy consumption.

17

Effect of acetic acid on pollutant decomposition in textile wastewater treated by the Fenton method

Kos L., Michalska K., Żyłła R., Perkowski J.

Environment Protection Engineering

|

2012

|

Vol. 38, nr 2

29--39

EN

The aim of the study was to determine the effect of acetic acid on pollutant decomposition in textile wastewater subjected to the Fenton process. To clearly assess the effect of acetic acid on treatment efficiency for subsequent types of textile wastewater, COD reduction was calculated for mixtures of a given wastewater type with acetic acid. The calculated COD values were compared to COD obtained in experiments with the oxidation of wastewater-acetic acid mixtures in the Fenton process. The presence of acetic acid seriously deteriorated conditions of wastewater treatment which affected the efficiency of treatment processes.

18

COD removal from landfill leachate using H2O2, UV radiation and combination these processes

Pieczykolan B., Barbusiński K., Płonka I.

Environment Protection Engineering

|

2012

|

Vol. 38, nr 3

5--13

EN

Experiments for removal of organic compounds (expressed as COD) from "young" municipal landfill leachate, using oxidation by H 2O2, UV photooxidation and UV/H 2O2 process, were carried out on a laboratory scale. Studies have shown that the most effective method was UV/H 2O2 process. When oxidation was conducted under the most suitable conditions (parameters found during experiments), maximum value of COD removal equaled 74.6%, 19.6% and 19.3% when the treatment was realized by use of H 2O2/UV, H 2O2 and UV radiation, respectively. These results demonstrate that in order to attain high efficiency of COD removal, use of advanced oxidation process (H 2O2/UV) is necessary.

19

Effect of Thermal Disintegration of Excess Sludge on the Effectiveness of Hydrolysis Process in Anaerobic Stabilization

Zawieja I., Wolski P.

Archives of Environmental Protection

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2012

|

Vol. 38, no. 1

103-114

EN

The factor which essentially affects sludge biodegradation rate is the degree of fluidization of insoluble organic polymers to the solved form, which is a precondition for availability of nutrients for microorganisms. The phases which substantially limit the rate of anaerobic decomposition include hydrolytic and methanogenic phase. Subjecting excess sludge to the process of initial disintegration substantially affects the effectiveness of the process of anaerobic stabilization. As a result of intensification of the process of hydrolysis, which manifests itself in the increase in the value and rate of generating volatile fatty acids (VFA), elongation of methanogenic phase of the process and increase in the degree of fermentation of modified sludge can be observed. Use of initial treatment of sewage sludge i.e. thermal disintegration is aimed at breaking microorganisms' cells and release of intracellular organic matter to the liquid phase. As a result of thermal hydrolysis in the sludge, the volatile fatty acids (VFA) are generated as early as at the stage of the process of conditioning. The obtained value of VFA determines the course of biological hydrolysis which is the first phase of anaerobic stabilization. The aim of the present study was to determine the effect of thermal disintegration of excess sludge on the effectiveness of the process of hydrolysis in anaerobic stabilization i.e. the rate of production of volatile fatty acids, changes in the level of chemical oxygen demand (COD) and increase in the degree of reduction in organic matter. During the first stage of the investigations, the most favourable conditions of thermal disintegration of excess sludge were identified using the temperatures of 50°C, 70°C, 90°C and heating times of 1.5 h - 6 h. The sludge was placed in laboratory flasks secured with a glass plug with liquid-column gauge and subjected to thermal treatment in water bath with shaker option. Another stage involved 8-day process of anaerobic stabilization of raw and thermally disintegrated excess sludge. Stabilization was carried out in mesophilic temperature regime i.e. at 37°C, under periodical conditions. In the case of the process of anaerobic stabilization of thermally disintegrated excess sludge at the temperature of 50°C and heating time of 6 h (mixture B) and 70°C and heating time of 4.5% (mixture C), the degree of fermentation of 30.67% and 33.63%, respectively, was obtained. For the studied sludge, i.e. mixture B and mixture C, maximal level of volatile fatty acids i.e. 874.29 mg CH3COOH/dm3 and 1131.43 mg CH3COOH/dm3 was found on the 2nd day of the process. The maximal obtained value of VFA was correlated on this day with maximal COD level, which was 1344 mg O2/dm3 for mixture B and 1778 mg O2/dm3 for mixture C.

PL

Za czynnik wpływający w istotny sposób na szybkość biodegradacji osadów uważany jest stopień upłynnienia nierozpuszczalnych polimerów organicznych do postaci rozpuszczonej, warukującej dostępność substancji odżywczych dla mikroorganizmów. Fazami ograniczającymi szybkość beztlenowego rozkładu są faza hydrolityczna i metanogenna. Poddanie osadów nadmiernych procesowi wstępnej dezintegracji znacząco wpływa na efektywność procesu stabilizacji beztlenowej. W wyniku intensyfikacji procesu hydrolizy, przejawiającej się wzrostem wartości oraz zwiększeniem szybkości generowania lotnych kwasów tłuszczowych (LKT), można zaobserwować wydłużenie fazy metanogennej procesu oraz wzrost stopnia przefermentowania modyfikowanych osadów. Zastosowanie wstępnej obróbki osadów ściekowych, tj. m.in. termicznej dezintegracji osadów, ma na celu rozbicie komórek mikroorganizmów oraz uwolnienie wewnatrzkomórkowej materii organicznej do fazy ciekłej. W wyniku zachodzącej hydrolizy termicznej osadów następuje już na etapie procesu kondycjonowania generowanie lotnych kwasów tłuszczowych (LKT). Uzyskana wartość LKT determinuje przebieg hydrolizy biologicznej, stanowiącej pierwszą fazę stabilizacji beztlenowej. Celem badań było określenie wpływu termicznej dezintegracji osadów nadmiernych na efektywność procesu hydrolizy w stabilizacji beztlenowej, tj. szybkość produkcji lotnych kwasów tłuszczowych, zmiany wartości ChZT oraz wzrost stopnia redukcji substancji organicznych. W pierwszym etapie badań dokonano określenia najkorzystniejszych warunków termicznej dezintegracji osadów nadmiernych stosując temperaturę 50°C, 70°C, 90°C i czas ogrzewania 1,5 h - 6 h. Osady umieszczone w kolbach laboratoryjnych, zamknięte szklanym korkiem z rurką manometryczną, poddano termicznej obróbce w łaźni wodnej z wytrząsaniem. W kolejnym etapie przeprowadzono 8-dobowy proces stabilizacji beztlenowej surowych oraz dezintegrowanych termicznie osadów nadmiernych. Stabilizacje prowadzono w mezofilowym reżimie temperatur tj. 37°C, w warunkach okresowych. W przypadku procesu stabilizacji beztlenowej termicznie dezintegrowanych osadów nadmiernych w temperaturze 50°C i czasie ogrzewania 6 h (Mieszanina B) oraz 70°C i czasie ogrzewania 4,5 h (Mieszanina C) uzyskano stopień przefermentowania wynoszący odpowiednio: 30,67% oraz 33,63%. Dla badanych osadów, tj. Mieszaniny B oraz C, maksymalną wartość lotnych kwasów tłuszczowych, tj. 874,29 mg CH3COOH/dm3 i 1131,43 mg CH3COOH/dm3, uzyskano w 2 dobie procesu. Z otrzymaną maksymalną wartością LKT korelowała odnotowana w ww. dobie procesu maksymalna wartość wskaźnika ChZT, wynosząca dla mieszaniny B 1344 mg O2/dm3, natomiast dla Mieszaniny C 1778 mg O2/dm3.

20

Wpływ czasu przetrzymania próbek ścieków na chemiczne zapotrzebowanie tlenu

Masiuk S., Rakoczy R., Kordas M., Grądzik P.

Inżynieria i Aparatura Chemiczna

|

2011

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Nr 5

70-71

PL

W pracy przedstawiono analizę wpływu czasu przetrzymywania próbek ścieku surowego na chemiczne zapotrzebowanie tlenu (wskaźnik ChZT. Zaproponowano zależność analityczną pozwalająca na wyznaczenie błędu indeksu ChZT w zależności od opóźnienia analizy próbki. Słowa kluczowe: ścieki, chemiczne zapotrzebowanie tlenu, czas przetrzymywania próbki.

EN

This paper presents the influence of the lag time of raw sewage probes on the index COD. The obtained analytical relationship may be applied to determine the error of COD index for the sewage probes.