Anaerobic treatment of blended sugar industry and ethanol distillery wastewater through biphasic high rate reactor

This study aimed to investigate the physicochemical properties of sugar industry and ethanol distillery wastewater and the treatment of the blended wastewater through a two-stage anaerobic reactor. For this treatment, different initial chemical oxygen demand (COD) concentrations (5-20g/L) and hydraulic retention times (HRTs) (2-10days) were applied. The sugar industry effluent characteristics obtained in terms of organic matter (mg/L) were as follows: 5days biochemical oxygen demand (BOD5): 654.5-1,968; COD: 1,100-2,148.9; total solids (TS): 2,467-4,012mg/L; and pH: 6.93-8.43. The ethanol distillery spent wash strengths obtained were: BOD5: 27,600-42,921mg/L; COD: 126,000-167,534mg/L; TS: 140,160-170,000mg/L; and pH: 3.9-4.2. Maximum COD removal of 65% was obtained at optimum condition (initial COD concentration of 10g/L and HRT of 10days), and maximum color removal of 79% was recorded under similar treatment conditions. Hence, the performance of the two-stage anaerobic reactor for simultaneous removal of COD and color from high-strength blended wastewater is promising for scaling up in order to mitigate environmental problems of untreated effluent discharge

Physicochemical properties of the sugar industry and ethanol distillery wastewater and their impact on the environment

The sugar industries and ethanol distilleries have been rapidly expanding globally since bioethanol emerged as a renewable bioenergy source. However, these industries generate large volumes of wastewater with high levels of organic matter, nutrients, and metal contents, which are discharged into the nearby environment without adequate treatment. This industrial pollution may have an adverse effect on aquatic and terrestrial ecosystems. Hence, this study aimed at investigating the physicochemical properties and metal constituents of sugar industry and ethanol distillery wastewater and its adverse effect on the environment. The study also assessed the legal framework of industrial wastewater management in the sugar-ethanol industry. The wastewater samples were collected from Metahara sugar factory and ethanol distillery using timecomposite sampling techniques. The laboratory analyses of physicochemical parameters and metal constituents of the wastewater were performed using standard methods. Results show that the physicochemical properties of the sugar industry's wastewater (mg/L) were pH 7.6 +/- 0.5, total solids (TS): 3050 +/- 628, 5 days biochemical oxygen demand (BOD5): 1052 +/- 560, chemical oxygen demand (COD): 1752 +/- 433.0, NO3 -N: 0.4 +/- 0.3, PO4 -3 : 3.5 +/- 1.5, SO4 -2 : 30 +/- 9.0 and Cl -: 45 +/- 10.4, whereas the ethanol distillery parameters (mg/L) were pH 3.9 +/- 0.1, TS: 150,300 +/- 9200, BOD5: 40,271 +/- 3014, COD: 132,445 +/- 6655, NO3 -N: 3.2 +/- 1.0, PO4 -3 : 21.2 +/- 2.7, SO4 -2 : 4502 +/- 69 and Cl -: 6722 +/- 873. The metal constituents of the sugar industry and ethanol distillery wastewater were, respectively: Na: 61.1-113.4, 207.6-263.0 mg/L; K: 87-161, 1143.9-2987.0 mg/L; Mg: 274.2-341.0, 816.3-927.6 mg/L; Ca: 376.9-468, 1787.4-3389.8 mg/L; Cr: 0.01-0.06, 0.8-2.3 mg/L; Cu: 0.2-0.7, 1.1-1.5 mg/L; Zn: 1.3-3.5, 1.4-2.8 mg/L; Fe: 3.2-4.3, 13.8-19.6 mg/L; Ni: not detected, 0.13-2.7 mg/L and Mn: 1-1.5, 1.5-6.6 mg/L. All except one bivariate correlation between concentrations of the metals were strong (r[ 0.5). The BOD5/COD (biodegradability index) of the sugar industry was 0.60, whereas the ethanol distillery was 0.25. Analysis of variance showed the concentrations of metals in the two industries were statistically significant (p\ 0.05). Most of the parameters in this study were beyond the maximum permissible discharging limits, possibly interfering with physicochemical and biological processes in the natural environment. Hence, for the benefits of the environmental safeguards and sustainable water use of the sector, we recommend that the two wastewaters be treated using integrated approaches through blending using the biological method

Anwendungsmöglichkeiten neuartiger EDV-gestützter Erkennungsmethoden zur Identifizierung gefährlicher Betriebszustände in Chemieanlagen (I)

Das Vorhaben erbrachte einen Beitrag zur operatorunabhängigen Beurteilung des Prozeß- und Anlagenzustandes chemischer Reaktoren, insbesondere zur Identifizierung gefährlicher Betriebszustände bei der diskontinuierlichen Fahrweise exothermer Reaktionen. Die Eignung von Mustererkennungsmethoden zur Prozeßdiagnose wurde am Beispiel eines chemischen Laborreaktors für einen stark exothermen Referenzprozeß - säurekatalysierte Veresterung von Essigsäureanhydrid mit Methanol - untersucht. Vor ihrer Anwendung als Zustandsklassifikator mußten die Mustererkennungssysteme zunächst mit den Prozeßdaten des normalen und gestörter Reaktionsverläufe unter Zuhilfenahme von Expertenwissen trainiert werden, um das komplexe nichtlineare Prozeßverhalten bis hin zum Entscheidungsresultat abzubilden. Danach konnte der trainierte Klassifikator zur Prozeßdiagnose genutzt werden. Die besten Ergebnisse bei der Erkennung von Betriebszuständen in Semibatch-Prozessen wurden mit dreischichtigen Perceptron-Netzen erreicht. Sie konnten auch Mehrfachfehler und nichttrainierte Reaktionsverläufe klassifizieren. Um das Gefährdungspotential von fehlerhaften Betriebszuständen beurteilen zu können, wurden separate Perceptron-Netze für die Gefahren- und Fehlerklassifikation eingesetzt. Ihre Leistungsfähigkeit wurde sowohl für den Semibatch-Betrieb als auch für die kontinuierliche Fahrweise experimentell nachgewiesen

Free radical suspension polymerization kinetics of styrene up to high conversion

Styrene was polymerized using different amounts of azoisobutyronitrile as initiator at temperatures of 70°C, 75°C and 80°C in suspension. The course of reaction up to almost complete conversion was modeled within a classical kinetic framework. Optimal simultaneous descriptions of both conversion and average degree of polymerization data were possible using two sets of values for the variation of the overall termination rate coefficient kt with conversion. One explanation for this is that kt is chain length dependent. Evidence for this necessity was derived by considering all kinetic parameters, except the termination rate coefficient, as reliable absolute values

Bioremediation of brewery wastewater using hydroponics planted with vetiver grass in Addis Ababa, Ethiopia

Abstract Background Bioremediation is the use of biological interventions for mitigation of the noxious effects caused by pollutants in the environment including wastewater. It is very useful approach for a variety of applications in the area of environmental protection. It has become an attractive alternative to the conventional cleanup technologies that employ plants and their associated microorganisms to remove, contain, or render harmless environmental contaminants. Methods Three parallel hydroponic treatment systems (each 2 m long × 0.75 m wide × 0.65 m deep) and one control unit were filled with brewery wastewater to an effective depth of 0.5 m. Two sets of floating polystyrene platform were used for each treatment unit to support vetiver tillers for conducting bioremediation study. The wastewater was fed to the hydroponic treatment units at hydraulic loading rate of 10 cm d−1 and hydraulic residence time of 5 days. Influent and effluent samples were collected once a month for 7 months, and analyzed to determine the various parameters relating to the water quality including plant growth and nutrient analyses. Results Vetiver grass grew and established with well-developed root and shoots in the hydroponics under fluctuations of brewery wastewater loads and showed phytoremedial capacity to remove pollutants. Removal efficiencies for BOD5 and COD were significant (p < 0.05), up to 73% (748–1642 mg l−1 inlet), and up to 58% (835–2602 mg l−1 inlet), respectively. Significant removal efficiencies (p < 0.05) ranged from 26 to 46% (14–21 mg l−1 inlet) for TKN, 28–46% (13–19 mg l−1 inlet) for NH4 +-N, 35–58% (4–11 mg l−1 inlet) for NO3 −-N, and 42–63% (4–8 mg l−1 inlet) for PO4−3-P were recorded. Nutrient accumulation in the samples harvested were varied between 7.4 and 8.3 g N kg−1 dry weight and 6.4–7.5 g P kg−1 dry weight in the hydroponic treatment units during the study period. Conclusions This study has shown suitability of vetiver grass for organics and nutrient removal in the bioremediation of brewery wastewater using hydroponics technique in addition to production of valuable biomass. Bioremediation using hydroponics is green and environmentally sustainable approach that offers promising alternative for wastewater treatment in developing countries including Ethiopia

An integrated treatment technology for blended wastewater of the sugar industry and ethanol distillery

This study was designed to evaluate physicochemical properties of the sugar industry and ethanol distillery wastewater, and treat the blended wastewater of the two industries using anaerobic digestion followed by adsorption of bagasse fly ash (BFA). The wastewater samples of the two industries were collected using composite and grab- sampling techniques. The application of the integrated treatment method was performed using an initial COD concentration of 10,000 mg/L, at the hydraulic retention time of 10 days, pH 7 and a constant temperature (37 degrees C) of the bioreactor, whereas the adsorption treatment was operated at the optimum point of BFA dose (4 g in 100 mL) and contact time (4 h) obtained in previous studies. Most of the physicochemical parameters of the two wastewaters were above the effluent discharging limits, which have the potential to cause adverse effects on the environment by interfering with physicochemical and biological processing. Under anaerobic treatment, maximum COD reduction of 65% and color removal of 79% were recorded, whereas after adsorption treatment, COD reduction of 62% and color removal of 58% were observed. However, the integration of the two aforementioned treatment technologies resulted in an average COD reduction of 76% and color removal of 83%, which indicates a promising option to mitigate pollution of untreated wastewater and enhance the practices of reusing the treated wastewater at the industrial scales. Finally, it can be concluded that the treated effluent can also be reused for irrigation of sugarcane which will contribute to sustainable water utilization in the sector

Adsorption of distillery spent wash on activated bagasse fly ash : kinetics and thermodynamics

This study aimed to characterize distillery spent wash and COD removal from it using bagasse fly ash (BFA). The results of the analyses showed that the average value of BOD5 and COD were 35,990 mgL(-1) and 13,9671 mgL(-1), respectively. High amount of total nitrogen (1217 mgL(-1)), total phosphorous (45 mgL(-1)), total solids (156 mgL(-1)) and low acidity (pH 4) were recorded. Adsorption of this spent wash on BFA was investigated at different temperatures, contact times, initial COD concentrations, pH solutions and adsorbent (BFA) doses. Raising temperature from 15 to 328 K resulted in increasing the uptake of the organic matter from 29.5 to 75.5%. Varying the initial COD concentration from 1000 mgL(-1) to 6000 mgL(-1) increased the adsorptivity capacity (q(e)) from 6 to 92.40 mg g(-1) and resulted in an increase in removal efficiency from 24 to 61.6%. Adsorptive capacity (116.30 mg g(-1)) calculated by the pseudo-second order model (R-2 = 0.98) indicated that pseudo-second order kinetic model fitted better with the experimental data. Moreover, the Gibbs free energy change (Delta G) (-5.61 to -11.84 kJ mol(-1))) showed that adsorption process was spontaneous whereas the positive value of the Delta H (42.29 kJ mol(-1)) indicates an endothermic process. Similarly, increasing the degree of disorder at the liquid-solids interfaces was observed from entropy change (Delta S = 0.17 kJ (Kmol)(-1)). In general, thermodynamic study revealed that adsorption process was feasible, spontaneous and endothermic; and the application of BFA is the promising option for removal of organic matter (COD) from molasses spent wash

Isolation and screening of low-density polyethylene (LDPE) bags degrading bacteria from Addis Ababa municipal solid waste disposal site “Koshe”

Abstract Purpose This study aims to screen bacterial isolates from the Addis Ababa municipal solid waste dumping site (Koshe) for the biodegradation of low-density polyethylene bags and analyzes their efficiency in degrading plastic bags. Methods In this study, low-density polyethylene bag-degrading bacteria were isolated from the Koshe municipal solid waste disposal area in Addis Ababa, Ethiopia. Screening of isolates for low-density polyethylene bag biodegradation was carried out using a clear zone method. Additionally, the efficiency of the isolates for low-density polyethylene biodegradation was evaluated using the weight loss method, scanning electron microscopy analysis, and Fourier transform infrared analysis. Finally, molecular identification of potential low-density polyethylene degrader bacterial isolates was done by 16S rDNA sequencing. Results Isolates KS35, KS14, and KS119 resulted in significant weight loss of low-density polyethylene film (42.87 ± 1.91%, 37.2 ± 3.06%, and 23.87 ± 0.11% weight loss, respectively). These isolates were selected for further biodegradation study using scanning electron microscopy and Fourier transform infrared analysis. Scanning electron microscopy analysis shows the formation of pores, pits, and distortion of the plastic surface. Fourier transform infrared analysis indicates the appearance of new peaks at the surface of low-density polyethylene films. Phylogenetic analysis of the three potential bacterial isolates was also carried out, and the result indicates that the sequence of isolate KS35 had 99% similarity with sequences of Methylobacterium radiotolerans MN525302. Isolate KS119 had 100% similarity with Methylobacterium fujisawaense KT720189, and the sequence of isolate KS14 had 99% similarity with species of Lysinibacillus fusiformis. Conclusions Weight loss, scanning electron microscopy analysis, and Fourier transform infrared analysis results show that isolates KS35, KS14, and KS119 have high potential in degrading low-density polyethylene bags

Fatty acid methyl esters production from crude waste frying oil using modified coffee husk ash catalyst: Parameters optimization

In this study, a KNO3-loaded coffee husk (CH) ash catalyst was synthesized to produce waste frying oil methyl ester (WFOME) from crude waste frying oil (WFO). Taguchi method optimization was performed to identify the best set of reaction temperature, time, catalyst loading and methanol to WFO molar ratio for maximum WFOME yield. A catalyst composite material (CCM) which is a mixture of CH char and KNO3 (0–65 wt%) was calcined to obtain the catalyst. The KNO3 loading and CCM calcination time effects on the catalyst performance and physicochemical properties were examined. The combustion behavior of the CH and CCMs was investigated using thermal analysis techniques. Utilizing FTIR, XRD, BET, SEM, and pH measurements, the catalyst characterization was carried out. For analytical sample sizes (during thermal analysis) with high KNO3 loading, the thermal reactivity was higher. However, for larger sample sizes (during catalyst synthesis) higher KNO3 loading decreased the CCM global thermal reactivity due to an oxygen permeation resisting ash deposition on the top surface. Thus, KNO3 tuned the catalyst’s physicochemical properties as a function of its loading (optimum 45 wt%) by affecting the combustion characteristics of the CCMs and basic site concentration. The optimum WFOME yield was 97.99 wt% at a reaction temperature of 65 °C, a reaction time of 1.13 h, a catalyst loading of 5.42 wt%, and a methanol to WFO molar ratio of 13.55:1. The WFOME yield was dropped by 46.93 wt% in three consecutive catalyst reuse tests because of active components leaching

Sugarcane biorefineries wastewater: bioremediation technologies for environmental sustainability

Abstract Sugarcane is known to be one of the oldest cultivated plants in tropical and subtropical countries. Sugar industries are increasing exponentially to satisfy the growing demand for sugar; whereas, the ethanol distilleries have been rapidly expanding, since bioethanol emerged as an affordable, low carbon footprint and renewable bioenergy. However, inadequately treated and indiscriminate disposal of the effluent from sugarcane industries resulted in extensive soil and water pollutions. Hence, this study aimed at reviewing the sugarcane industrial process with its water consumption rates, and effluent characteristics and its adverse effects on the environment. Finally, the study has gone through the most common wastewater treatment efforts made to minimize the effluent environmental burden. In addition to the large volumes of sugar and ethanol industrial effluents, the presence of the different varieties of the pollutants in the effluent is challenging for conventional treatment methods. However, eliminating the pollutants is becoming important for environmental and esthetic values. In line with this, a number of studies encompassing physicochemical and biological treatment methods have been conducted but many of them failed to be effective. Furthermore, alternative treatments have also been developed such as recycling of vinasse, fertirrigation and concentrated by evaporation but they were not effective either due to the high energy use or the large effluent volumes which cannot be managed through such methods. However, anaerobic digestion of high rate was found in the state of the art and an effective approach to treat the sugar industry and ethanol distillery effluents