Performance of triple ditch: effects of duration and periodic operation programs

The periodic variation of operation states in triple ditch (BIO-DENITRO process) was investigated in a pilot-scale and a full-scale triple ditch treating raw wastewater containing 70% petrochemical wastewater and 30% domestic wastewater. Mathematical models describing the periodic variation of activated sludge concentrations in each ditch were proposed based on theoretical analysis and were verified in the pilot-scale and full-scale triple ditches respectively. The existence of optimal cycle time and time arrangement of periodic operation programs were demonstrated and discussed according to the mathematical models and the experimental results of the pilot-scale triple ditch operated in four different stages. Four rulers determining the duration and operation programs are suggested.

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Comparative study of domestic wastewater treatment efficiencies between facultative pond and water spinach pond

Water Science & Technology ◽

10.2166/wst.1995.0148 ◽

1995 ◽

Vol 32 (3) ◽

pp. 263-270 ◽

Cited By ~ 12

Author(s):

Seni Karnchanawong ◽

Jaras Sanjitt

Keyword(s):

Growth Rates ◽

Domestic Wastewater ◽

Pilot Scale ◽

Organic Content ◽

Water Spinach ◽

Removal Rates ◽

Mass Removal ◽

Loading Rates ◽

Tropical Conditions ◽

Average Water

Two pilot-scale studies were comparatively conducted under tropical conditions during December 1992 to September 1993. One study involved facultative ponds(FP) and the others water spinach ponds(SP). Four rectangular concrete ponds, 0.8 m × 2.4 m × 1.1 m (width × length × depth), were employed to treat the Chiang Mai University campus wastewater. Water spinach (Ipomoea aquatica) was planted in two of the ponds. The influent characteristics noted showed a low organic content, i.e. BOD 25.4-29.9 mg/l, with BOD:N ratio around 1:1. The investigations were conducted using the following hydraulic retention times (HRT): 1.6, 2, 2.7, 4, 8 and 16 d. The results showed that the BOD, COD and SS mass removal rates increased as the mass loading rates increased and the SP was significantly more effective in reducing the organic content than the FP. No relationship was found between TN mass removal and the loading rates. However, the TP mass removal rates in the SP and the FP were rather low and were considered to be insignificant. It was observed that SS accumulated in the water spinach root systems which tended to act as a strainer. This process led to plant growth inhibition and finally die-off. The average water spinach growth rates varied from 37 to 107 g wet wt./(m2.d) and no relationship was established between the growth rates and the HRT.

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Theoretical analysis and experiments for the carburization of vanadium-bearing hot metal

Metallurgical Research & Technology ◽

10.1051/metal/2017084 ◽

2018 ◽

Vol 115 (2) ◽

pp. 204

Author(s):

Deng Ma ◽

Wei Wu ◽

Shifan Dai ◽

Zhibin Liu

Keyword(s):

Theoretical Analysis ◽

Thermodynamic Analysis ◽

Induction Furnace ◽

Cost Effective ◽

Pilot Scale ◽

Hot Metal ◽

Temperature Range ◽

Vanadium Extraction ◽

Low Nitrogen

In this study, the feasibility of the carburization of vanadium-bearing hot metal was first investigated by thermodynamic analysis. Next, three carburizers, namely a low-nitrogen carburizer, anthracite, and coke, were used for carburization of 500 g of vanadium-bearing hot metal at 1450 °C, 1500 °C, and 1550 °C, respectively. The carbon increments for the low-nitrogen carburizer, anthracite and coke followed decreasing order in the temperature range from 1450 °C to 1550 °C. Anthracite was the most cost-effective carburizer. Hence, anthracite is used in pilot-scale experiments of the vanadium-bearing hot metal (100 kg and 200 kg). Finally, vanadium extraction experiments of the vanadium-bearing hot metal were carried out in a top-bottom-combined blowing induction furnace. It is proved that the average superheat degree of semi-steel increases from 100 °C to 198 °C by the carburization of vanadium-containing hot metal.

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Anaerobic hydrolysis of complex substrates in full-scale aerobic granular sludge: enzymatic activity determined in different sludge fractions

Applied Microbiology and Biotechnology ◽

10.1007/s00253-021-11443-3 ◽

2021 ◽

Author(s):

Sara Toja Ortega ◽

Mario Pronk ◽

Merle K. de Kreuk

Keyword(s):

Hydrolytic Enzymes ◽

Oxygen Demand ◽

Domestic Wastewater ◽

Granular Sludge ◽

Hydrolytic Activity ◽

Full Scale ◽

Aerobic Granular Sludge ◽

Bulk Liquid ◽

Granule Formation ◽

Hydrolysis Of

Abstract Complex substrates, like proteins, carbohydrates, and lipids, are major components of domestic wastewater, and yet their degradation in biofilm-based wastewater treatment technologies, such as aerobic granular sludge (AGS), is not well understood. Hydrolysis is considered the rate-limiting step in the bioconversion of complex substrates, and as such, it will impact the utilization of a large wastewater COD (chemical oxygen demand) fraction by the biofilms or granules. To study the hydrolysis of complex substrates within these types of biomass, this paper investigates the anaerobic activity of major hydrolytic enzymes in the different sludge fractions of a full-scale AGS reactor. Chromogenic substrates were used under fully mixed anaerobic conditions to determine lipase, protease, α-glucosidase, and β-glucosidase activities in large granules (>1 mm in diameter), small granules (0.2–1 mm), flocculent sludge (0.045–0.2 mm), and bulk liquid. Furthermore, composition and hydrolytic activity of influent wastewater samples were determined. Our results showed an overcapacity of the sludge to hydrolyze wastewater soluble and colloidal polymeric substrates. The highest specific hydrolytic activity was associated with the flocculent sludge fraction (1.5–7.5 times that of large and smaller granules), in agreement with its large available surface area. However, the biomass in the full-scale reactor consisted of 84% large granules, making the large granules account for 55–68% of the total hydrolytic activity potential in the reactor. These observations shine a new light on the contribution of large granules to the conversion of polymeric COD and suggest that large granules can hydrolyze a significant amount of this influent fraction. The anaerobic removal of polymeric soluble and colloidal substrates could clarify the stable granule formation that is observed in full-scale installations, even when those are fed with complex wastewaters. Key points • Large and small granules contain >70% of the hydrolysis potential in an AGS reactor. • Flocculent sludge has high hydrolytic activity but constitutes <10% VS in AGS. • AGS has an overcapacity to hydrolyze complex substrates in domestic wastewater. Graphical abstract

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Enhancing nitrogen removal efficiency in a dyestuff wastewater treatment plant with the IFFAS process: the pilot-scale and full-scale studies

Water Science & Technology ◽

10.2166/wst.2017.522 ◽

2017 ◽

Vol 77 (1) ◽

pp. 70-78 ◽

Cited By ~ 4

Author(s):

Yanjun Mao ◽

Xie Quan ◽

Huimin Zhao ◽

Yaobin Zhang ◽

Shuo Chen ◽

...

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Removal Efficiency ◽

Nitrogen Removal ◽

Treatment Plant ◽

Oxygen Demand ◽

Pilot Scale ◽

Full Scale ◽

Nitrification And Denitrification ◽

Dyestuff Wastewater

Abstract The activated sludge (AS) process is widely applied in dyestuff wastewater treatment plants (WWTPs); however, the nitrogen removal efficiency is relatively low and the effluent does not meet the indirect discharge standards before being discharged into the industrial park's WWTP. Hence it is necessary to upgrade the WWTP with more advanced technologies. Moving bed biofilm processes with suspended carriers in an aerobic tank are promising methods due to enhanced nitrification and denitrification. Herein, a pilot-scale integrated free-floating biofilm and activated sludge (IFFAS) process was employed to investigate the feasibility of enhancing nitrogen removal efficiency at different hydraulic retention times (HRTs). The results showed that the effluent chemical oxygen demand (COD), ammonium nitrate (NH4+-N) and total nitrogen (TN) concentrations of the IFFAS process were significantly lower than those of the AS process, and could meet the indirect discharge standards. PCR-DGGE and FISH results indicated that more nitrifiers and denitrifiers co-existed in the IFFAS system, promoting simultaneous nitrification and denitrification. Based on the pilot results, the IFFAS process was used to upgrade the full-scale AS process, and the effluent COD, NH4+-N and TN of the IFFAS process were 91–291 mg/L, 10.6–28.7 mg/L and 18.9–48.6 mg/L, stably meeting the indirect discharge standards and demonstrating the advantages of IFFAS in dyestuff wastewater treatment.

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Nitrogen removal and N2O emission in a full-scale domestic wastewater treatment plant with intermittent aeration

Journal of Fermentation and Bioengineering ◽

10.1016/s0922-338x(98)80114-1 ◽

1998 ◽

Vol 86 (2) ◽

pp. 202-206 ◽

Cited By ~ 115

Author(s):

Yuzuru Kimochi ◽

Yuhei Inamori ◽

Motoyuki Mizuochi ◽

Kai-Qin Xu ◽

Masatoshi Matsumura

Keyword(s):

Wastewater Treatment ◽

Nitrogen Removal ◽

Wastewater Treatment Plant ◽

Treatment Plant ◽

Domestic Wastewater ◽

N2o Emission ◽

Full Scale ◽

Intermittent Aeration ◽

Domestic Wastewater Treatment

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Performance of Four Full-Scale Artificially Aerated Horizontal Flow Constructed Wetlands for Domestic Wastewater Treatment

Water ◽

10.3390/w8090365 ◽

2016 ◽

Vol 8 (9) ◽

pp. 365 ◽

Cited By ~ 13

Author(s):

Eleanor Butterworth ◽

Andrew Richards ◽

Mark Jones ◽

Gabriella Mansi ◽

Ezio Ranieri ◽

...

Keyword(s):

Wastewater Treatment ◽

Constructed Wetlands ◽

Domestic Wastewater ◽

Full Scale ◽

Horizontal Flow ◽

Domestic Wastewater Treatment

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Model-based evaluation of a new upgrading concept for N-removal

Water Science & Technology ◽

10.2166/wst.2002.0104 ◽

2002 ◽

Vol 45 (6) ◽

pp. 169-176 ◽

Cited By ~ 25

Author(s):

S. Salem ◽

D. Berends ◽

J.J. Heijnen ◽

M.C.M. van Loosdrecht

Keyword(s):

Mathematical Modelling ◽

Scale Up ◽

Treatment Plant ◽

Ammonia Concentration ◽

Pilot Scale ◽

Full Scale ◽

Model Based ◽

N Removal ◽

Quantitative Basis ◽

Treatment Concepts

Mathematical modelling is considered a time and cost-saving tool for evaluation of new wastewater treatment concepts. Modelling can help to bridge the gap between lab and full-scale application. Bio-augmentation can be used to obtain nitrification in activated sludge systems with a limited aerobic sludge retention time. In the present study the potential for augmenting the endogenous nitrifying population is evaluated. Implementing a nitrification reactor in the sludge return line fed with sludge liquor with a high ammonia concentration leads to augmentation of the native nitrifying population. Since the behaviour of nitrifiers is relatively well known, a choice was made to evaluate this new concept mainly based on mathematical modelling. As an example an existing treatment plant (wwtp Walcheren, The Netherlands) that needed to be upgraded was used. A mathematical model, based on the TUDP model and implemented in AQUASIM was developed and used to evaluate the potential of this bioaugmentation in the return sludge line. A comparison was made between bio-augmentation and extending the existing aeration basins and anoxic tanks. The results of both modified systems were compared to give a quantitative basis for evaluation of benefits gained from such a system. If the plant is upgraded by conventional extension it needs an increase in volume of about 225%; using a bioaugmentation in the return sludge line the total volume of the tanks needs to be expanded by only 75% (including the side stream tanks). Based on the modelling results a decision was made to implement the bioaugmentation concept at full scale without further pilot scale testing, thereby strongly decreasing the scale-up period for this process.

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