K. Barbusiński

INFLUENCE OF SUBSTRATE LOADING INTENSITY ON FLOC SIZE IN ACTIVATED SLUDGE PROCESS

Abstract The activated sludge flocs size variability and their size distribution were analyzed for the flocs sizes larger than 10 μm and for different intensities (rates) of bidirectional organic loading changes. Under these conditions the distributions of floc sizes expressed as average diameter and longest dimension fitted well the log-normal model. The logarithmic average floc size variability proved to be proportional to the loading if a time delay due to the inertia of biochemical and physical processes of activated sludge was taken into account. It has also been found that flocs larger than 50 μm constituted the main source of the surface area and volume of the activated sludge. The tests performed have shown that organic loading strongly influences floc size distribution in the activated sludge process. The long-term loading changes caused larger disturbances to the floc size distribution than more rapid but shorter ones. Generally, after the substrate overload occurred, the flocs were more prone to breakup (pin-point floc effect).

Comparison of Landfill Leachate Treatment Efficiency Using the Advanced Oxidation Processes

Abstract Treatment of leachate from an exploited since 2004 landfill by using two methods of advanced oxidation processes was performed. Fenton’s reagent with two different doses of hydrogen peroxide and iron and UV/H2O2 process was applied. The removal efficiency of biochemically oxidizable organic compounds (BOD5), chemically oxidizable compounds using potassium dichromate (CODCr) and nutrient (nitrogen and phosphorus) was examined. Studies have shown that the greatest degree of organic compounds removal expressed as a BOD5 index and CODCr index were obtained when Fenton’s reagent with greater dose of hydrogen peroxide was used - efficiency was respectively 72.0% and 69.8%. Moreover, in this case there was observed an increase in the value of ratio of BOD5/CODCr in treated leachate in comparison with raw leachate. Application of Fenton’s reagent for leachate treatment also allowed for more effective removal of nutrients in comparison with the UV/H2O2 process. Przeprowadzono badania oczyszczania odcieków pochodzących z eksploatowanego od 2004 roku składowiska odpadów za pomocą dwóch metod pogłębionego utleniania. Wykorzystano odczynnik Fentona z dwoma różnymi dawkami nadtlenku wodoru i żelaza oraz proces UV/H2O2. Sprawdzano efektywność usuwania związków organicznych utlenialnych biochemicznie (BZT5) i chemicznie za pomocą dwuchromianu potasu (ChZTCr) oraz związków biogennych (azotu i fosforu). Badania wykazały, że największy stopień usunięcia związków organicznych wyrażonych zarówno jako wskaźnik BZT5 jak i ChZTCr uzyskano podczas stosowania odczynnika Fentona z większą dawką nadtlenku wodoru - efektywność odpowiednio wyniosła 72% i 69,8%. Ponadto w tym przypadku odnotowano wzrost wartości stosunku BZT5/ChZTCr w odciekach oczyszczonych w odniesieniu do odcieków surowych. Zastosowanie oczyszczania odcieków odczynnikiem Fentona pozwoliło również na większą skuteczność usuwania związków biogennych w porównaniu z procesem UV/H2O2.

Synthetic Textile Wastewater Treatment using Potassium Ferrate(VI) – Application of Taguchi Method for Optimisation of Experiment

5 State Higher Vocational School in Tarnów, Institute of Mathematical and Natural Science, ul. Mickiewicza 8, 33-100 Tarnów, Poland Abstract The article attempts to assess the usefulness of the Taguchi method to optimise the purification process of synthetic textile wastewater (pH 6.7 7.2, Conductivity = 6.71 6.84 mS/cm, Salinity = 3581 3648 mg NaCl/l, Colour = 560 4710 mg Pt/l, COD = 2220 2290 mg O2/l, TOC = 394 551 mg/l) using K2FeO4. The research was conducted using 3 types of wastewater containing anionic detergent (sodium lauryl sulfate, 100 mg/l) and differing only in the concentration of azo dye Acid Green 16 (AG 16). Technical K2FeO4 was used as an oxidiser, which was subjected to physico-chemical analysis (purity, UV-VIS spectrum, surface characteristics and chemical composition using SEM and EDX methods). For planning and optimising the wastewater treatment process, the Taguchi method was used for four input parameters: pH (2, 7, 12), reaction time (10, 30, 50 min), AG 16 concentrations (20, 120, 220 mg/l) and K2FeO4 concentrations (25, 125, 225 mg/l), for which 9 experiments were performed in accordance with the plan adopted. Test result analysis allowed to indicate the optimal values for individual input parameters (pH 2, time = 50 min, AG 16 = 20 mg/l, K2FeO4 = 125 mg/l). Under these conditions, visual discoloration of wastewater was obtained (AG 16 = 0.4 mg/l, ↓98% ), colour removal (66 mg Pt/l, ↓88%) and DOC (249 mg/l, ↓37%).

A Rapid and Simple TLC-Densitometric Method for Assay of Clobetasol Propionate in Topical Solution

A rapid, simple to use and low-cost thin-layer chromatographic procedure in normal phase system with densitometric detection at 246 nm was carefully validated according to the International Conference on Harmonisation (ICH) guidelines for assay of clobetasol propionate in topical solution containing clobetasol propionate in quantity 0.50 mg/mL. The adopted thin-layer chromatographic (TLC)-densitometric procedure could effectively separate clobetasol propionate from its related compound, namely clobetasol. It is linear for clobetasol propionate in the range of 0.188 ÷ 5 µg/spot. The limit of detection (LOD) and limit of quantification (LOQ) value is 0.061 and 0.186 µg/spot, respectively. Accuracy of proposed procedure was evaluated by recovery test. The mean recovery of studied clobetasol propionate ranges from 98.7 to 101.0%. The coefficient of variation (CV, %) obtained during intra-day and inter-day studies, which was less than 2% (0.40 ÷ 1.17%), confirms the precision of described method. The assay value of clobetasol propionate is consistent with the pharmacopoeial requirements. In conclusion, it can be suitable as a simple and economic procedure for routine quality control laboratories of clobetasol propionate in topical solution.

Optimization of the Fenton Oxidation of Synthetic Textile Wastewater using Response Surface Methodology

This article presents the possibility of using the classical Fenton process (Fe(II)/H2O2) to purify synthetic textile wastewater (COD = 1872 mg O2/dm, TOC = 660 mg/dm3) containing azo dye Anilan Blue GRL 250% (200 mg/dm3) and sodium lauryl sulphate (SLS) as anionic surfactant at a concentration of 95 mg/dm3. Model studies were carried out using RSM, obtaining a good fit of approximated values to experimental values (R2 = 0.9461 and Radj = 0.7379). For optimal process parameters (pH 3, Fe(II) 0.85 g/dm3, H2O2 14.5 g/dm3), complete decolourisation (<10 mg Pt/dm3) was achieved as well as a reduction in COD, TOC and SLS concentrations to 83%, 44% and 98%, respectively.

Evaluation of the impact of explanatory variables on the accuracy of prediction of daily inflow to the sewage treatment plant by selected models nonlinear

Abstract The aim of the study was to evaluate the possibility of applying different methods of data mining to model the inflow of sewage into the municipal sewage treatment plant. Prediction models were elaborated using methods of support vector machines (SVM), random forests (RF), k-nearest neighbour (k-NN) and of Kernel regression (K). Data consisted of the time series of daily rainfalls, water level measurements in the clarified sewage recipient and the wastewater inflow into the Rzeszow city plant. Results indicate that the best models with one input delayed by 1 day were obtained using the k-NN method while the worst with the K method. For the models with two input variables and one explanatory one the smallest errors were obtained if model inputs were sewage inflow and rainfall data delayed by 1 day and the best fit is provided using RF method while the worst with the K method. In the case of models with three inputs and two explanatory variables, the best results were reported for the SVM and the worst for the K method. In the most of the modelling runs the smallest prediction errors are obtained using the SVM method and the biggest ones with the K method. In the case of the simplest model with one input delayed by 1 day the best results are provided using k-NN method and by the models with two inputs in two modelling runs the RF method appeared as the best.