Sulfate Reduction under Acidic Conditions in High Rate Bioreactor Systems for Treatment of Mining and Metallurgical Waste and Process Water

Anaerobic treatment of sulfate - rich (COD/SO4 ratio 1.4-2.1) clarified Whitewater from a thermomechanical pulping (TMP) process was studied in three laboratory-scale upflow anaerobic sludge blanket (UASB) reactors at 55°C and in batch digesters at 55° and 65°C. Different seed materials were used in the UASB reactors. The highest COD removal efficiency (effluent sulfide stripped) achieved was approximately 65 % in the UASB reactors. About 55 % COD removal efficiency was obtained at a loading rate of about 41 kgCODm−3d−1 in the UASB reactor seeded with thermophilic sludge cultivated with volatile fatty acids (VFAs). The total sulfide present in the liquid phase after anaerobic treatment accounted for approximately 65-78 % and 15-61 % of the removed COD in the batch digesters and the UASB reactors, respectively. Sulfate reduction was almost complete in the batch digesters, whereas about 24-64 % of sulfate was reduced in the UASB reactors. Acetate utilization for sulfate reduction was apparent in the batch digesters, whereas that could not be demonstrated in the UASB reactors. Sulfate reduction in the UASB reactors was obviously substrate limited. In conclusion, thermophilic anaerobic treatment is an alternative for the treatment of warm sulfate rich TMP process water.

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Methanobacterium enables high rate electricity-driven autotrophic sulfate reduction

RSC Advances ◽

10.1039/c5ra18444d ◽

2015 ◽

Vol 5 (109) ◽

pp. 89368-89374 ◽

Cited By ~ 23

Author(s):

Guillermo Pozo ◽

Ludovic Jourdin ◽

Yang Lu ◽

Pablo Ledezma ◽

Jurg Keller ◽

...

Keyword(s):

Sulfate Reduction ◽

Electron Donor ◽

High Rate ◽

Bioelectrochemical Systems

The autotrophic reduction of sulfate can be sustained with a cathode as the only electron donor in bioelectrochemical systems (BES).

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Evaluation of Advanced Chemical Oxidation Process for the Pretreatment of Mixed Agro-Food Industrial Wastewater in Nablus, Palestine

10.20944/preprints202012.0777.v1 ◽

2020 ◽

Author(s):

Saja Younis ◽

Rashed Al-Sa`ed

Keyword(s):

Advanced Oxidation Process ◽

Oxidation Process ◽

Advanced Oxidation ◽

Chemical Oxidation ◽

Decision Makers ◽

High Rate ◽

Food Industries ◽

Acidic Conditions ◽

Pre Treatment ◽

Wastewater Samples

This study investigated the reduction of organic loads from mixed agro-food industrial wastewaters (dairy and slaughterhouse) of Nablus city using advanced oxidation process (AOP), a high- rate chemical oxidation reaction. Bench-scale Jar tests using an advanced oxidation process (AOP) were performed as a pretreatment stage. Direct applications of classical Fenton’s process on mixed raw agro-food wastewater samples (COD: 15400-18200 mg/l) revealed unsatisfactory results. The performance of the Fenton process was evaluated using three mixed samples with different pre-treatment trials: (A) coagulant (FeCl3.6H2O) addition, (B) settling (2h) allowed, and use of flocculent (lime Ca(OH)2) in sample (C). Compared with other partial treatments, sample (C), Fenton`s process lime preceded, was the most effective in the removal of organic (89% COD; 80% TKN) and inorganic loads (91% TSS; 62% TS) under H2O2/COD (w/w ratio 2:1), H2O2/Fe+2 (w/w ratio 10:1) and acidic conditions (pH =3). Obtained results comply with Nablus municipal by-law (COD below 2000 mg/l), which help decision-makers within the agro-food industries install pollution reduction systems. Investment in the Fenton-based peroxidation process, allow agro-food industries to obtain connection permits to sewage networks.

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