An optimal operating strategy for fixed-bed bioreactors used in wastewater treatment

Wastewater treatment has always been a major concern in the developed countries. Over the last few decades, activated carbon adsorption has gained importance as an alternative tertiary wastewater treatment and purification process. In this study, granular activated carbon (GAC) adsorption was evaluated in terms of total organic carbon (TOC) removal from low strength synthetic wastewater. This paper provides details on adsorption experiments conducted on synthetic wastewater to develop suitable adsorption isotherms. Although the inorganics used in the synthetic wastewater solution had an overall unfavourable effect on adsorption of organics, the GAC adsorption system was found to be effective in removing TOC from the wastewater. This study showed that equation of state (EOS) theory was able to fit the adsorption isotherm results more precisely than the most commonly used Freundlich isotherm. Biodegradation of the organics with time was the most crucial and important aspect of the system and it was taken into account in determining the isotherm parameters. Initial organic concentration of the wastewater was the determining factor of the model parameters, and hence the isotherm parameters were determined covering a wide range of initial organic concentrations of the wastewater. As such, the isotherm parameters derived using the EOS theory could predict the batch adsorption and fixed bed adsorption results of the multi-component system successfully. The isotherm parameters showed a significant effect on the determination of the mass transfer coefficients in batch and fixed bed systems.

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Application of Catalytic Wet Peroxide Oxidation for Industrial and Urban Wastewater Treatment: A Review

Catalysts ◽

10.3390/catal8120673 ◽

2018 ◽

Vol 8 (12) ◽

pp. 673 ◽

Cited By ~ 18

Author(s):

Juan Rueda Márquez ◽

Irina Levchuk ◽

Mika Sillanpää

Keyword(s):

Wastewater Treatment ◽

Advanced Oxidation Process ◽

Fixed Bed ◽

Toxicity Assessment ◽

Batch Reactors ◽

Peroxide Oxidation ◽

Urban Wastewater ◽

Wet Peroxide Oxidation ◽

Catalytic Wet Peroxide Oxidation ◽

Urban Wastewater Treatment

Catalytic wet peroxide oxidation (CWPO) is emerging as an advanced oxidation process (AOP) of significant promise, which is mainly due to its efficiency for the decomposition of recalcitrant organic compounds in industrial and urban wastewaters and relatively low operating costs. In current study, we have systemised and critically discussed the feasibility of CWPO for industrial and urban wastewater treatment. More specifically, types of catalysts the effect of pH, temperature, and hydrogen peroxide concentrations on the efficiency of CWPO were taken into consideration. The operating and maintenance costs of CWPO applied to wastewater treatment and toxicity assessment were also discussed. Knowledge gaps were identified and summarised. The main conclusions of this work are: (i) catalyst leaching and deactivation is one of the main problematic issues; (ii) majority of studies were performed in semi-batch and batch reactors, while continuous fixed bed reactors were not extensively studied for treatment of real wastewaters; (iii) toxicity of wastewaters treated by CWPO is of key importance for possible application, however it was not studied thoroughly; and, (iv) CWPO can be regarded as economically viable for wastewater treatment, especially when conducted at ambient temperature and natural pH of wastewater.

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Kinetics of sugar mill wastewater treatment by down-flow anaerobic fixed bed reactors

Bioprocess Engineering ◽

10.1007/bf00369432 ◽

1996 ◽

Vol 14 (3) ◽

pp. 145-150 ◽

Cited By ~ 3

Author(s):

E. S�nchez ◽

R. Borja ◽

L. Travieso

Keyword(s):

Wastewater Treatment ◽

Fixed Bed ◽

Sugar Mill ◽

Fixed Bed Reactors ◽

Kinetics Of

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Optimal operating strategy of high-temperature heat and power storage system coupled with a wind farm in energy market

Energy ◽

10.1016/j.energy.2020.118545 ◽

2020 ◽

Vol 210 ◽

pp. 118545

Author(s):

Mohammad Ali Lasemi ◽

Ahmad Arabkoohsar

Keyword(s):

High Temperature ◽

Wind Farm ◽

Storage System ◽

Energy Market ◽

Optimal Operating ◽

Operating Strategy ◽

Temperature Heat ◽

Power Storage

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Fixed Biomass Activity in Aerobic Biological Reactors Used for Wastewater Treatment

Water Science & Technology ◽

10.2166/wst.1988.0332 ◽

1988 ◽

Vol 20 (11-12) ◽

pp. 489-491

Author(s):

J. C. Block ◽

N. Nouvion ◽

J. M. Cahen ◽

Y. Lesty ◽

G. M. Faup

Keyword(s):

Wastewater Treatment ◽

Oxygen Uptake ◽

Fixed Bed ◽

Fixed Bed Reactor ◽

Biomass Growth ◽

Head Losses ◽

Uptake Rates ◽

Biomass Activity ◽

Potential Activity ◽

Experimental Runs

Experimental runs were carried out on an upflow fixed-bed reactor. The process cycle of 24 hours was determined by following head losses used as an indicator of the clogging of the filter and of the biomass growth. Thanks to a protocol of dispersion of the biomass present into the filter, two fractions defined as fixed and shared biomass were obtained. The specific dehydrogenase activities or the specific oxygen uptake rates of the dispersed biomass were always greater than those of the fixed biomass. The aggregation of the biomass into the reactor prevents its potential activity being used to the full.

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Innovative low cost procedure for nutrient removal as an integrated element of a decentralised water management concept for rural areas

Water Science & Technology ◽

10.2166/wst.2001.0025 ◽

2001 ◽

Vol 44 (1) ◽

pp. 105-112 ◽

Cited By ~ 4

Author(s):

M. Burde ◽

F. Rolf ◽

F. Grabowski

Keyword(s):

Wastewater Treatment ◽

Nutrient Removal ◽

Rural Areas ◽

Municipal Wastewater ◽

Wastewater Treatment Plants ◽

Low Cost ◽

Fixed Bed ◽

Extreme Rainfall ◽

Fixed Bed Reactor ◽

Soil Zone

The absence of large rivers with rather high niveau of self purifying effect in parts of east Germany leads to a discharging of the effluent of wastewater treatment plants into the groundwater in many cases. One useful consequence is the idea of realisation of decentralised measures and concepts in urban water resources management concerning municipal wastewater as well as rainfall, precipitation. At the same time, only the upper soil zone - a few decimetres - is water - saturated and thus discharge effective, even when extreme rainfall takes place. Underneath, however, there generally exists an unsaturated soil zone, which is up to now a rather unexplored retardation element of the hydrologic- and substrate-cycle. Nutrient removal in small wastewater treatment plants that are emptying into ground waters is often beneficial. The presented studies optimised an inexpensive method of subsequent enhanced wastewater treatment. The developed reactor is similar to a concentrated subsoil passage. The fixed bed reactor is divided in two sections to achieve aerobic and anoxic conditions for nitrification/denitrification processes. To enhance phosphorus removal, ferrous particles are put into the aerobic zone. Two series of column tests were carried out and a technical pilot plant was built to verify the efficiency of the process. The results show that this method can be implemented successfully.

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Anaerobic-Aerobic Treatment of Municipal Wastewaters with Full-Scale Upflow Anaerobic Sludge Blanket and Attached Biofilm Reactors

Water Science & Technology ◽

10.2166/wst.1990.0171 ◽

1990 ◽

Vol 22 (1-2) ◽

pp. 475-482 ◽

Cited By ~ 13

Author(s):

C. Collivignarelli ◽

G. Urbini ◽

A. Farneti ◽

A. Bassetti ◽

U. Barbaresi

Keyword(s):

Wastewater Treatment ◽

Energy Consumption ◽

Fluidized Bed ◽

Municipal Wastewater ◽

Fixed Bed ◽

Upflow Anaerobic Sludge Blanket ◽

Anaerobic Sludge ◽

Municipal Wastewater Treatment ◽

Municipal Wastewaters ◽

Anaerobic Sludge Blanket

The results of pilot experiments on municipal wastewater treatment using advanced processes are described. The most important aims of this research were to achieve reductions in energy consumption, environmental impact, quantity of stabilized sludge produced, and area necessary for plant construction. The pilot plant, which was constructed in the environs of the Senigallia (AN, Italy) municipal wastewater treatment plant, had a capacity of 500 to 2500 population equivalents (p.e.). In the most attractive system, municipal wastewaters with a low organic concentration were first treated in an upflow anaerobic sludge blanket (UASB) bioreactor with a capacity of 336 m3. Part of the effluent from this process was then conveyed to an anoxic biological fluidized bed (with a volume of 8 m3 filled with 3 m3 of quartzite sand) for pre-denitrification, and then to an aerobic fixed bed (with random plastic media and a volume of 8m3) for nitrification. It was also possible to treat the municipal wastewaters using the anaerobic fluidized bed directly, after microscreening or primary sedimentation. The research undertaken was intended to verify the reliability of these processes at ambient temperatures and with variable wastewater concentrations. The preliminary results obtained for COD, BOD, and N removal from municipal wastewaters indicate that this system is quite an attractive treatment alternative, mainly due to its low sludge production and energy consumption. These results will enable accurate design criteria to be identified for the construction of more economic treatment plants on a larger scale.

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