Sludge reduction by uncoupling metabolism: SBR tests with para-nitrophenol and a commercial uncoupler

Abstract

Nowadays cost reduction is a very important issue in wastewater treatment plants. One way, is to minimize the sludge production. Microorganisms break down the organic matter into inorganic compounds through catabolism. Uncoupling metabolism is a method which promote catabolism reactions instead of anabolism ones, where adenosine triphosphate synthesis is inhibited. In this work, the influence of the addition of para-nitrophenol and a commercial reagent to a sequencing batch reactor (SBR) on sludge production and process performance has been analyzed. Three laboratory SBRs were operated in parallel to compare the effect of the addition of both reagents with a control reactor. SBRs were fed with synthetic wastewater and were operated with the same conditions. Results showed that sludge production was slightly reduced for the tested para-nitrophenol concentrations (20 and 25 mg/L) and for a LODOred dose of 1 mL/day. Biological process performance was not influenced and high COD removals were achieved.

A study of the osmotic membrane bioreactor process using a sodium chloride solution and an industrial effluent as draw solutions

“…The high stress caused by the quick conductivity increase and the high increase of the ammonium nitrogen concentration were responsible for the cell lysis. Furthermore, it was detected a direct relation between DNA and protein concentrations, what corroborates that measured proteins could come from the released cellular material from the bacteria, as previously published Zuriaga et al [42].…”

A comparative study of the influence of salt concentration on the performance of an osmotic membrane bioreactor and a sequencing batch reactor

“…The analysis of DNA was studied to observe whether cell lyses occurred. 43 In this case, for SBR, DNA concentrations did not vary significantly with the operation time. However, for OMBR, DNA concentration decreased with operation time, which indicates that biomass was adapted progressively to the operating conditions of the OMBR.…”

“…The analysis of DNA was studied to observe whether cell lyses occurred . In this case, for SBR, DNA concentrations did not vary significantly with the operation time.…”

Comparison of Excess Sludge Reduction Effect of Dichlorophenol Isomers

“…Prior studies have generally focused on the effects of spiked addition of uncoupling agents to sludge [13], and no studies have examined the extended addition of uncoupling agents. Previous studies by the present authors on spiked addition of 3,5-DCP to similar fed-batch reactors also showed that the capacity of 3,5,-DCP to reduce the quantity of sludge produced was lost in approximately 3 weeks [12].…”