Biological sulfate reduction (BSR) (or sulfidogenic) biotechnology is becoming a promising solution for treatment of various organic-deficient sulfate-laden wastewater. Through a combination of external dosage of organic waste, it provides a more economic and energy efficient treatment than existing technology options for sulfur-induced pollution. The applicability and operation efficiency of BSR biotechnology build on the determination of the biodegradable particulate organics (BPO) fraction and its corresponding conversion rates under sulfidogenic environments. However, no method exists for the determination of such biodegradability, except for the biochemical methane potential (BMP) test building on methanogenic environments. While the applicability of BMP test for sulfidogenic proce...[ Read more ]

Biological sulfate reduction (BSR) (or sulfidogenic) biotechnology is becoming a promising solution for treatment of various organic-deficient sulfate-laden wastewater. Through a combination of external dosage of organic waste, it provides a more economic and energy efficient treatment than existing technology options for sulfur-induced pollution. The applicability and operation efficiency of BSR biotechnology build on the determination of the biodegradable particulate organics (BPO) fraction and its corresponding conversion rates under sulfidogenic environments. However, no method exists for the determination of such biodegradability, except for the biochemical methane potential (BMP) test building on methanogenic environments. While the applicability of BMP test for sulfidogenic process has not been verified, this study aims to develop a specific biochemical sulfide potential (BSP) test and its extended applications for the current initiative in BSR biotechnology.

In part one, the feasibility of the BSP test was first explored by a comparison with the BMP test for biodegradability characterization of sulfate-laden primary sewage sludge. The results indicated that 2.6 times more chemical oxygen demand (COD) were converted in BSP test, where 1.48 times more volatile suspended solids (VSS) in the particulate organics were destructed. Moreover, the BSP test required a test duration of 4 days which is 89% shorter than the 35 days in the BMP test. The first-order hydrolysis model revealed that the faster test duration in BSP test was resulted from the enhanced hydrolysis rates of both readily and slowly biodegradable organics under sulfidogenic environments, and they are respectively about 8 times and 10 times faster when compared to the BMP test. The findings highlight the inapplicability and unnecessary long duration in BMP test for BSR biotechnology. In part two, to extend the application of BSP test, casein-based validation was carried out to explore the capacity of BSP test for identifying BPO elemental composition (C_xH_yO_zN_aP_bS_c). Applying the identified BPO elemental composition as an input variable, a BSP biochemical kinetic model was further developed to realize process simulation in BSR biotechnology. In part three, to standardize BSP test in its implementation, several potential factors were investigated, and the results showed the optimal testing conditions should follow an initial inoculum-to-substrate ratio (ISR) of 2 and dissolved sulfide concentration of 500 mg-S/L under temperature of 22 °C instead of 37 °C which is commonly used in BMP test. In conclusion, this study not only develop a specific BSP test for organics biodegradability characterization in BSR biotechnology, but also realize its performance prediction thus facilitating the process design, operation evaluation and system optimization.