Waste activated sludge fermentation liquid as carbon source for biological treatment of sulfide and nitrate in microaerobic conditions

Carbon, nitrogen, and phosphorus need to be recovered to reduce the environmental impact of waste activated sludge (WAS). In this study the improved short-chain fatty acid (SCFA) production from WAS by the addition of kitchen waste to adjust the ratio of carbon to nitrogen (C/N), and the efficient recovery of nitrogen and phosphorus from the fermentation liquid were reported. Firstly, the optimum conditions for SCFA production were found to be pH 8, temperature 35 °C, C/N ratio 21 mg-C/1 mg-N, and fermentation time 6 d, using the response surface methodology. After alkaline fermentation, the struvite precipitation method was applied to efficiently and simultaneously recover the released ammonia and phosphorus from the fermentation liquid. Finally, the fermentation liquid was used as the additional carbon source for biological nitrogen and phosphorus removal. It was observed that, compared with acetic acid, the use of fermentation liquid as carbon source showed greater removal efficiencies of total nitrogen and total phosphorus.

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Waste Activated Sludge Alkaline Fermentation Liquid as Carbon Source for Biological Nutrients Removal in Anaerobic Followed by Alternating Aerobic-Anoxic Sequencing Batch Reactors

Chinese Journal of Chemical Engineering ◽

10.1016/s1004-9541(10)60246-7 ◽

2010 ◽

Vol 18 (3) ◽

pp. 478-485 ◽

Cited By ~ 28

Author(s):

Xiong ZHENG ◽

Yinguang CHEN ◽

Chenchen LIU

Keyword(s):

Carbon Source ◽

Activated Sludge ◽

Waste Activated Sludge ◽

Batch Reactors ◽

Sequencing Batch Reactors ◽

Nutrients Removal ◽

Fermentation Liquid ◽

Biological Nutrients Removal

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Microalgae as biological treatment for municipal wastewater – effects on the sludge handling in a treatment plant

Water Science & Technology ◽

10.2166/wst.2018.334 ◽

2018 ◽

Vol 78 (3) ◽

pp. 644-654 ◽

Cited By ~ 3

Author(s):

J. Olsson ◽

S. Schwede ◽

E. Nehrenheim ◽

E. Thorin

Keyword(s):

Heavy Metals ◽

Activated Sludge ◽

Biological Treatment ◽

Municipal Wastewater ◽

Treatment Plant ◽

Waste Activated Sludge ◽

Activated Sludge Process ◽

Primary Sludge ◽

Thermophilic Conditions ◽

Mesophilic Conditions

Abstract A mix of microalgae and bacteria was cultivated on pre-sedimented municipal wastewater in a continuous operated microalgae-activated sludge process. The excess material from the process was co-digested with primary sludge in mesophilic and thermophilic conditions in semi-continuous mode (5 L digesters). Two reference digesters (5 L digesters) fed with waste-activated sludge (WAS) and primary sludge were operated in parallel. The methane yield was slightly reduced (≈10%) when the microalgal-bacterial substrate was used in place of the WAS in thermophilic conditions, but remained approximately similar in mesophilic conditions. The uptake of heavy metals was higher with the microalgal-bacterial substrate in comparison to the WAS, which resulted in higher levels of heavy metals in the digestates. The addition of microalgal-bacterial substrate enhanced the dewaterability in thermophilic conditions. Finally, excess heat can be recovered in both mesophilic and thermophilic conditions.

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