Hydraulic retention time affects stable acetate production from tofu processing wastewater in extreme-thermophilic (70 °C) mixed culture fermentation

Hydrogen production from molasses wastewater was investigated in continuously-stirred tank reactor (CSTR). The CSTR was operated at an hydraulic retention time (HRT) of 6 hours and the temperature at 35°C. The highest gas production of 25.39 L/d using mixed culture fermentation, corresponding to a peak hydrogen production volume of 11.39 L/d were achieved in the CSTR reactor. While the variation of chemical oxygen demand (COD) ranged from 5500 to 8000 mg/L, the soluble end product system underwent a transition of fermentation type and the reactor gave ﬂuctuating and increasing of ORP. These experimental results demonstrate that the shock-loading and micro-anaerobic circumstance are important factors for enhancing and stabilizing H2 production.

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The nitrogen removal potential of predenitrification systems in sensitive coastal areas

Water Science & Technology ◽

10.2166/wst.1995.0218 ◽

1995 ◽

Vol 32 (7) ◽

pp. 135-142

Author(s):

E. Görgün ◽

N. Artan ◽

D. Orhon ◽

R. Tasli

Keyword(s):

Water Quality ◽

Wastewater Treatment ◽

Nitrogen Removal ◽

Retention Time ◽

Treatment Process ◽

Hydraulic Retention Time ◽

Domestic Sewage ◽

Coastal Areas ◽

Careful Evaluation ◽

Denitrification Kinetics

Effective nitrogen removal is now required to protect water quality in sensitive coastal areas. This involves a much more difficult treatment process than for conventional domestic sewage as wastewater quantity and quality exhibits severe fluctuations in touristic zones. Activated sludge is currently the most widely used wastewater treatment and may be upgraded as a predenitrification system for nitrogen removal. Interpretation of nitrification and denitrification kinetics reveal a number of useful correlations between significant parameters such as sludge age, C/N ratio, hydraulic retention time, total influent COD. Nitrogen removal potential of predenitrification may be optimized by careful evaluation of wastewater character and the kinetic correlations.

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Evaluation of a tropical single-cell waste stabilization pond system for irrigation

Water Science & Technology ◽

10.2166/wst.1995.0495 ◽

1995 ◽

Vol 31 (12) ◽

pp. 267-273 ◽

Cited By ~ 4

Author(s):

B. S. O. Ceballos ◽

A. Konig ◽

B. Lomans ◽

A. B. Athayde ◽

H. W. Pearson

Keyword(s):

Single Cell ◽

Removal Efficiency ◽

Retention Time ◽

Hydraulic Retention Time ◽

Full Scale ◽

Waste Stabilization Pond ◽

North East ◽

Helminth Eggs ◽

Waste Stabilization ◽

Better Than

A single full-scale primary facultative pond in Sapé, north-east Brazil was monitored for performance and efficiency. The pond had a hydraulic retention time of 61 days and achieved a 95% BOD5 removal efficiency and had no helminth eggs in the effluent. The effluent failed to meet the WHO faecal coliform guideline for unrestricted irrigation. The pond was dominated by the cyanobacterium Microcystis and gave better than predicted orthophosphate removal. Details of how the system could be simply upgraded utilizing the same land are discussed.

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