Esra Yel

Prediction of primary treatment effluent parameters by Fuzzy Inference System (FIS) approach

Abstract A fuzzy-logic-based diagnosis system was developed to determine the primary treatment effluent quality in a municipal wastewater treatment plant (MWTP). The measured data of variables were implemented into the Fuzzy Inference System (FIS) with Mamdani’s method. The fuzzy control rule base was shaped to define essential quality parameters monitored as pH, COD, BOD and SS outputs. The output approximations to real data remained in an acceptable range for a MWTP performance (89–96%). The averages and standard deviations of the model were also approximated closely as 93–98% and 89–97%, respectively. The resulting configuration proved a good modeling approach for MWTP effluent quality prediction.

Photo/photochemical oxidation of cyanide and metal-cyanide complexes: ultraviolet A versus ultraviolet C.

Degradation of free cyanide (CN−), weak-acid dissociable (WAD) ( , ) and strong-acid dissociable (SAD) cyanide complexes by photo and photochemical oxidation with ultraviolet (UV) light and H2O2 was investigated. The experiments were performed in batch reactors under ultraviolet A (UVA; 395 nm) and ultraviolet C (UVC; 254 nm) light; the degradation efficiency was followed in terms of free cyanide, complex and metal concentrations. UVC and UVA photo-oxidations were found to be equally effective in CN− and WAD degradation, while the degradation of the SAD complex was more difficult for both UV wavelengths, and UVC was more effective. The initial pH of the solution has influenced the degradation of all cyanide species and the optimum initial pH was evaluated as 10.5 for CN− and ; 12.0 for and 9.0 for degradation. Photochemical oxidation using H2O2 provided higher degradation at shorter durations with both UVA and UVC. Time-dependent variations in free cyanide and metal concentrations have indicated that metal–cyanide complexes are firstly degraded into metal and CN− ions, followed by oxidation of CN− ions, while metals in the system were partially removed as hydroxide precipitates. Therefore, depending upon the effluent requirements, the studied UV photo/photochemical oxidations were offered as either a pre-treatment method for the separation of metal and the cyanide, or as an oxidation technology to degrade especially WAD complexes and CN−. Estimated operational cost of photo-oxidation by UVC was 1.6–2.5-fold higher than UVA degradation, although degradation times were close. In the photochemical oxidation with H2O2, the operational costs of UVC and UVA degradation were closer, owing to peroxide costs, but UVC was still more expensive.

Removal of Turbidity from Travertine Processing Wastewaters by Coagulants, Flocculants and Natural Materials

The sedimentation behaviour of travertine-processing wastewater containing a high concentration of suspended solids was investigated using different coagulation and flocculation methods. In batch experiments, four types of coagulants [FeC13, Al2(SO4)3, PACl, NaAlO2], six types of flocculants (40% MMW–40% HMW cationic, 30% MMW, 40% MMW, 40% HMW anionic and nonionic) and three types of natural materials (NMs) (sepiolite, zeolite, and pumice) were used to treat wastewater with an initial turbidity of 570–880 NTU. The optimum process conditions (dosage, mixing time/speed, sedimentation time, and pH) were investigated for each. Sedimentation performance was assessed by the effluent turbidity (Teff) values of the treated water. The best performances obtained were 99.3% (Teff = 4 NTU), 99.1% (Teff = 8 NTU), and 97.8% (Teff = 18 NTU) with 40% HMW anionic-cationic flocculants, zeolite, and FeCl3, respectively. Sludge properties, including sludge settling velocity (mm/min), sludge density (g/cm3), suspended solids (SS) content (mg/L), and sludge solids (%) were determined and compared under optimized conditions. The type of additive significantly affected performance. Travertine processing wastewater flocculation with polymeric materials and NMs, especially zeolite, was more favourable than coagulants in terms of both turbidity removal and sludge quality. Since zeolite is a NM, additional studies on using and recycling of the generated sludge as an industrial feedstock would be worthwhile.ZusammenfassungDas Sedimentationsverhalten von Feststoffen, die in hohen Konzentrationen im Abwasser einer Travertinverarbeitung enthalten sind, wurde unter Anwendung verschiedener Flockungsmethoden untersucht. In Batch-Experimenten wurden vier Flockungsmittel (FeCl3, Al2(SO4)3, PACl, NaAlO2), sechs Flockungshilfsmittel (40%MMW- 40%HMW kationisch, 30%MMW, 40%MMW, 40%HMW anionisch und kationisch) und drei natürliche Materialien (Sepidolith, Zeolith, Bimsstein) bei Anfangstrübungen von 550-880 NTU getestet. Für alle wurden die optimalen Bedingungen ermittelt: Dosis, Rührgeschwindigkeit und –zeit, Sedimentationszeit und pH-Wert. Als Bewertungskriterium für die Sedimentationsleistung der verschiedenen Methoden diente die Trübung des behandelten Wassers (Teff). Die besten Reinigungsleistungen lagen bei 99.3% (Teff=4 NTU), 99.1% (Teff=8 NTU) und 97.8% (Teff=18 NTU) mit 40% HMW anionisch-kationischem Flockungshilfsmittel, Zeolit bzw. FeCl3. Die Schlammeigenschaften (Sedimentationsgeschwindigkeit in mm/min, Schlammdicht in g/cm3, Feststoffgehalt in % und in mg/L) wurden unter optimalen Bedingungen bestimmt und verglichen. Die Art der eingesetzten Stoffe beeinflusste signifikant die Sedimentationsleistung. Die Behandlung mit Polymeren und natürlichen Materialien, insbesondere Zeolith, ist sowohl wegen der Trübeentfernung als wegen der Schlammeigenschaften gegenüber Flockungsmitteln zu bevorzugen. Da Zeolith ein natürliches Material ist, wären Untersuchungen zur Nutzung und zum Recycling des erzeugten Schlammes als Sekundärrohstoff in der Industrie wünschenswert.凝结剂、絮凝剂和天然材料去除石灰石石料加工厂废水浊度应用多种凝结剂和絮凝剂研究了石灰石石料加工厂含高浓度悬浮固体废水的沉淀行为。用四种凝结剂(FeC13、Al2(SO4)3、PACl和NaAlO2)、六种絮凝剂(40%MMW- 40%HMW 阳离子、30% MMW、40% MMW、40% HMW 阴离子和无离子)和三种天然材料(NMs)(海泡石、沸石和浮石) 批次试验方式处理了初始浊度570-880 NTU的石料加工厂废水。研究了每种处理试剂的最佳处理条件(剂量、混合时间/速度、沉淀时间和pH值)。利用出流液浊度(Teff)值评价沉淀效率。40% HMW 阴-阳离子絮凝剂、沸石和FeCl3的最佳效率分别为99.3% (Teff=4 NTU)、99.1% (Teff=8 NTU)、和97.8% (Teff=18 NTU)。对比了污泥沉降速度(mm/min)、污泥密度(g/cm3)、悬浮固体含量(SS)(mg/L)和污泥固体(%)等污泥质量指标。添加剂类型严重影响沉淀效率。聚合和天然絮凝剂(尤其是沸石)在同时去除石料加工厂废水浊度和保证污泥质量方面比凝结剂更具优势。沸石是天然材料,使用和回收水处理产生的污泥作为工业原料更值得深入研究。ResumenEl comportamiento en la sedimentación de aguas residuales del tratamiento de travertino, que contienen una alta concentración de sólidos en suspensión, fue estudiada usando diferentes métodos de coagulación y floculación. Se usaron cuatro tipos de coagulantes (FeC13, Al2(SO4)3, PACl, NaAlO2), seis tipos de floculantes (40%MMW- 40%HMW catiónico, 30%MMW, 40%MMW, 40%HMW aniónico y no iónico) y tres tipos de materiales naturales (NMs) (sepiolita, zeolita y piedra gómez) en experimentos en batch para tratar aguas residuales con una turbidez inicial de 570-880 NTU. Se investigaron las condiciones óptimas del proceso (dosaje, tiempo de mezclado/velocidad, tiempo de sedimentación y pH) en cada caso. El comportamiento sedimentativo fue evaluado por los valores de turbidez del efluente (Teff) del agua tratada. Las mejores eficiencias obtenidas fueron 99,3% (Teff=4 NTU), 99,1% (Teff=8 NTU) y 97,8% (Teff=18 NTU) con floculantes 40% HMW aniónico-catiónico, zeolita y FeCl3, respectivamente. Las propiedades del lodo, incluyendo la velocidad de sedimentación (mm/min), la densidad del lodo (g/cm3), contenido de sólidos en suspensión (SS) (mg/L) y sólidos en el lodo (%) se determinaron y compararon bajo condiciones optimizadas. El tipo de aditivo afectó significativamente la eficiencia del proceso. El procesamiento de las aguas residuales por floculación usando materiales poliméricos y NMs, especialmente zeolita, fue más favorable que con los coagulantes en términos de remoción de turbidez y calidad del lodo. Como la zeolita es un NM, valdrían la pena realizar estudios adicionales sobre el uso y el reciclado del lodo generado como una materia prima industrial maximum heights of bed and residual bed separations. These technologies were applied to the 1307 working face in the Xinji No. 1 coal mine, in Huainan, Anhui Province. Menacing bed separation was identified in the nappe fault zone. The maximum heights of the bed and residual bed separations were 5.92~6.90 m and 1.97~2.30 m, respectively.