Automated biological sulphate reduction: a review on mathematical models, monitoring and bioprocess control

In the sulphate-reducing process, bioprocess control can be used to regulate the competition between microbial groups, to optimize the input of the electron donor and/or to maximize or minimize the production of sulphide. As shown in this review, modelling and monitoring are important tools in the development and application of a bioprocess control strategy. Pre-eminent literature on modelling, monitoring and control of sulphate-reducing processes is reviewed. This paper firstly reviews existing mathematical models for sulphate reduction, focusing on models for biofilms, microbial competition, inhibition and bioreactor dynamics. Secondly, a summary of process monitoring strategies is presented. Special attention is given to in situ sensors for sulphate, sulphide and electron donor concentrations as well as for biomass activity and composition. Finally, the state of the art of the bioprocess control strategies in biological sulphate reduction processes is overviewed

Treatment of fish processing wastewater in a one or two step upflow anaerobic sludge blanket (UASB) reactor.

The performance of one-step UASB reactors treating fish processing wastewater of different lipid levels was determined using artificially generated influent simulating that of the canning of sardines and tuna. The organic loading rates (OLR) and the hydraulic retention times (HRT) were 5-8 g COD.l(-1).d(-1) and 11-12 hours, respectively. In treating a wastewater that contains 3-4 g.l(-1) total COD of which 5-9 as lipids, the COD removal and conversion to methane were ca.78nd 61°respectively. In treating a wastewater with a higher lipid content (ca. 47␘f the total COD), the total COD removed and converted to methane were 92nd 47°respectively. A considerable part of the influent total COD was removed via adsorption on reactor surfaces and sludge particles. The adsorption of lipids on sludge particles threatens the stability of the UASB operation. Thus, the performance of a first-step UASB reactor in removing suspended solids (SS) from a "high-lipid" wastewater was also determined in this study

Effluent standards for developing countries: combining the technology- and water quality-based approach

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Role of microbial accumulation in biological sulphate reduction using lactate as electron donor in an inversed fluidized bed bioreactor : Operation and dynamic mathematical modelling

This study evaluated the impact of substrate accumulation (sulphate and polyhydroxybutyrate (PHB)) on bioprocess control of a sulfate reducing inversed fluidized bed bioreactor. To investigate the impact of substrate accumulation, step feed changes were induced to an inversed fluidized bed bioreactor performing biological sulphate reduction. A first step feed change set both the chemical oxygen demand (COD) and sulphate influent concentration to zero. As hypothesised, sulphide was still being produced after 15 days of operation without electron donor and sulphate supply. This suggests that accumulated and/or sorbed COD and sulphate supported the continued biological sulphide production. PHB was indeed found present in the sludge and batch tests showed PHB can support the sulphate reduction. A second step feed change of adding solely COD (and no sulphate) to the bioreactor influent resulted in a continuous production of sulphide, suggesting that sulphate had accumulated in the inversed fluidized bed bioreactor sludge. A mathematical model that includes microbial growth, PHB and sulphate storage as well as metabolism of lactate oxidizing sulphate reducing bacteria was developed, calibrated and validated. The model was able to simulate the accumulation of both PHB and sulphate in the inversed fluidized bed bioreactor