Full-scale Process Research Articles

A completely theoretical approach for assessing fouling propensity along a full-scale reverse osmosis process

This paper aims to develop a completely theoretical approach for assessing scaling (crystallization/precipitation fouling) propensity through the previously proposed and tested theoretical index of 2nd author (SPI) within a Reverse Osmosis (RO) module. This approach will incorporate the local varying foulants' properties along membrane filtration channel into fundamental transport and conservation equations to achieve a unified and scientific assessment of the scaling potential. Thus, a high accuracy simulation of the local fouling propensity along a full-scale RO module will be obtained. This paper has overcome the challenge of determining and incorporating the locally varying concentration of foulants (and factors affecting it) and effect of concentration polarization to predict the local fouling propensity along the membrane channel. Also it has incorporated the only available theoretical index without any need for empirical parameters and/or constant Therefore, a fundamental more realistic description of fouling propensity and onset of fouling next to membrane along feed channel is developed and explained. Moreover, the effects of initial applied pressure, initial cross flow velocity, initial feed water salinity, clean membrane resistance and feed water temperature on fouling propensity and onset of fouling along the channel are investigated and discussed. Our suggested model is a very powerful tool that could help in the specific design of RO process as well as in simulations of the operating variables for optimization of RO system.

Improved utilization of fish waste by anaerobic digestion following omega-3 fatty acids extraction

Fish waste is a potentially valuable resource from which high-value products can be obtained. Anaerobic digestion of the original fish waste and the fish sludge remaining after enzymatic pre-treatment to extract fish oil and fish protein hydrolysate was evaluated regarding the potential for methane production. The results showed high biodegradability of both fish sludge and fish waste, giving specific methane yields of 742 and 828 m3CH4/tons VS added, respectively. However, chemical analysis showed high concentrations of light metals which, together with high fat and protein contents, could be inhibitory to methanogenic bacteria. The feasibility of co-digesting the fish sludge with a carbohydrate-rich residue from crop production was thus investigated, and a full-scale process outlined for converting odorous fish waste to useful products.

Adsorption with biodegradation for decolorization of reactive black 5 by Funalia trogii 200800 on a fly ash-chitosan medium in a fluidized bed bioreactor-kinetic model and reactor performance

A non-steady-state mathematical model system for the kinetics of adsorption and biodegradation of reactive black 5 (RB5) by Funalia trogii (F. trogii) ATCC 200800 biofilm on fly ash-chitosan bead in the fluidized bed process was derived. The mechanisms in the model system included adsorption by fly ash-chitosan beads, biodegradation by F. trogii cells and mass transport diffusion. Batch kinetic tests were independently performed to determine surface diffusivity of RB5, adsorption parameters for RB5 and biokinetic parameters of F. trogii ATCC 200800. A column test was conducted using a continuous-flow fluidized bed reactor with a recycling pump to approximate a completely-mixed flow reactor for model verification. The experimental results indicated that F. trogii biofilm bioregenerated the fly ash-chitosan beads after attached F. trogii has grown significantly. The removal efficiency of RB5 was about 95 % when RB5 concentration in the effluent was approximately 0.34 mg/L at a steady-state condition. The concentration of suspended F. trogii cells reached up to about 1.74 mg/L while the thickness of attached F. trogii cells was estimated to be 80 μm at a steady-state condition by model prediction. The comparisons of experimental data and model prediction show that the model system for adsorption and biodegradation of RB5 can predict the experimental results well. The approaches of experiments and mathematical modeling in this study can be applied to design a full-scale fluidized bed process to treat reactive dye in textile wastewater.

Exploring microbial communities and differences of cartridge filters (CFs) and reverse osmosis (RO) membranes for seawater desalination processes

Fouled cartridge filters (CFs) and reverse osmosis (RO) membrane samples were collected to study the differences in microbial communities for better understanding of the biofouling process in the industrial full-scale seawater desalination process. A culture-independent technique (16S rDNA sequencing analysis) showed that the microbial communities of CFs and RO membranes were extremely different. In the CF samples, Proteobacteria and Firmicutes were observed to be the dominant bacterial groups, whereas Proteobacteria, Planctomycetacia, and Planctomycetes were mainly present in the fouled RO membranes. Although the two samples were obtained from the same spot of the operating desalination plant, the results indicate that the microbial communities of biofouled CFs and RO membranes were different.

Microbial community analysis of three municipal wastewater treatment plants in winter and spring using culture-dependent and culture-independent methods

Low temperatures can result in start-up and operational problems in wastewater treatment plants. The microbial community structures of three full-scale biological processes for municipal wastewater treatment, namely, anoxic-oxic activated sludge (A/O) process, oxidation ditch, and sequencing batch reactor, in winter and spring were investigated. The performances of the three biological processes were all stable during winter and spring. Comparing all three plants, the NH(4) (+)-N removal efficiency using the A/O process was found to be the highest during both winter and spring. According to the similarity coefficient of the polymerase chain reaction and denaturing gradient gel electrophoresis analysis determined via the culture-independent method, the microbial community structure is the most stable using the A/O process at different temperatures. The dominant members primarily belonged to Proteobacteria, Nitrospira, and Bacteroidetes. In addition, Proteobacteria was the dominant member in the activated sludge utilizing peptone, glucose, and fatty acid. Compared with other biological processes, the A/O process was superior at low temperatures based on its pollution removal performance and stable microbial community sturcture.

Flotation model based on floatability component approach – PGE minerals case

This paper discusses how modelling and simulation can be used in predicting the recovery of platinum group elements (PGE) in flotation process. In platinum group ores, commonly a floatability component approach is used where each element is divided in model fitting to two or three components. This approach has the problem of breaking the natural association of platinum group element in minerals, floatability components do not have any physical meaning and as the model fitting problem is ill-posed, comparison of different tests by floatability component parameters is difficult. To avoid this modelling and simulation here is based on minerals. Additionally, the mass proportion of fast floating material was fixed on the basis of mineralogical study and results achieved in laboratory flotation tests. Finally as the rougher and cleaning flotation was performed in fixed chemical regime the model fitting was done for both rougher and cleaning stages simultaneously using cascade model. It was found in this way a number of model fitted parameters decreased giving possibility to compare tests results easier but still reaching good fit between observed, modelled and simulated data. The developed model was used in screening the best flotation conditions and to forecast the metallurgical performance in full scale process.

Evaluation of Three Full-scale Grit Removal Processes using CFD Modeling

Evaluation of Three Full-scale Grit Removal Processes using CFD Modeling

Effects of organic loading rate on reactor performance and archaeal community structure in mesophilic anaerobic digesters treating municipal sewage sludge

In this study, the organic loading rate (OLR) of a high-solids anaerobic digestion (HSAD) system was increased from 3.4 to 5.0 gVS L(-1) day(-1) and reactor stability, performance and microbial community structure were determined. Laboratory simulations (3.5 L) of the full-scale process (500 dry ton year(-1)) were conducted using continuously stirred-tank mesophilic reactors. OLRs of 3.4 gVS L(-1)day(-1) (equal to the full-scale HSAD), 4.0, 4.5 and 5.0 gVS L(-1)day(-1) were evaluated. Biochemical parameters and archaeal community dynamics were measured over 42 days of steady state operation. Results showed that increasing OLR increased the amount of organic matter conversion and resulted in higher organic matter removal and volumetric methane (CH₄) production (VMP) rates. The highest volatile solids (VS) removal and VMP results of 54 ± 2% and 1.4 ± 0.1 L CH₄ L(-1)day(-1) were observed for 5.0 gVS L(-1) day(-1). The efficiency of reactor conversion of organic matter to CH(4) was found to be similar in all the treatments with an average value of 0.57 ± 0.07 LCH(4) gVS(-1) (removed). 16S rRNA gene terminal restriction fragment polymorphism (T-RFLP) analyses revealed that archaeal TRFs remained stable during the experiment accounting for an average relative abundance (RA) of 81 ± 1%. Archaea consistent with multiple terminal restriction fragments (TRFs) included members of the Euryarchaeota and Crenarchaeota phyla, including acetoclastic and hydrogenotrophic groups. In conclusion, this laboratory-scale study suggests that performance and stability as well as the archaeal community structure in this HSAD system was unaffected by increasing the OLR by nearly 50% and that this increase resulted in a similar increase in the amount of CH(4) gas generated.

Effects of soluble and particulate substrate on the carbon and energy footprint of wastewater treatment processes

Most wastewater treatment plants monitor routinely carbonaceous and nitrogenous load parameters in influent and effluent streams, and often in the intermediate steps. COD fractionation discriminates the selective removal of VSS components in different operations, allowing accurate quantification of the energy requirements and mass flows for secondary treatment, sludge digestion, and sedimentation. We analysed the different effects of COD fractions on carbon and energy footprint in a wastewater treatment plant with activated sludge in nutrient removal mode and anaerobic digestion of the sludge with biogas energy recovery. After presenting a simple rational procedure for COD and solids fractions quantification, we use our carbon and energy footprint models to quantify the effects of varying fractions on carbon equivalent flows, process energy demand and recovery. A full-scale real process was modelled with this procedure and the results are reported in terms of energy and carbon footprint. For a given process, the increase of the ratio sCOD/COD increases the energy demand on the aeration reactors, the associated CO 2 direct emission from respiration, and the indirect emission for power generation. Even though it appears as if enhanced primary sedimentation is a carbon and energy footprint mitigation practice, care must be used since the nutrient removal process downstream may suffer from an excessive bCOD removal and an increased mean cell retention time for nutrient removal may be required.

Scale‐down of penicillin production in Penicillium chrysogenum

In large-scale production reactors the combination of high broth viscosity and large broth volume leads to insufficient liquid-phase mixing, resulting in gradients in, for example, the concentrations of substrate and oxygen. This often leads to differences in productivity of the full-scale process compared with laboratory scale. In this scale-down study of penicillin production, the influence of substrate gradients on process performance and cell physiology was investigated by imposing an intermittent feeding regime on a laboratory-scale culture of a high yielding strain of Penicillium chrysogenum. It was found that penicillin production was reduced by a factor of two in the intermittently fed cultures relative to constant feed cultivations fed with the same amount of glucose per hour, while the biomass yield was the same. Measurement of the levels of the intermediates of the penicillin biosynthesis pathway, along with the enzyme levels, suggested that the reduction of the flux through the penicillin pathway is mainly the result of a lower influx into the pathway, possibly due to inhibitory levels of adenosine monophosphate and pyrophosphate and lower activating levels of adenosine triphosphate during the zero-substrate phase of each cycle of intermittent feeding.

On-field study of anaerobic digestion full-scale plants (Part II): New approaches in monitoring and evaluating process efficiency

Biogas plants need easy and practical tools for monitoring and evaluating their biological process efficiency. As soon as, in many cases, biomass supply present considerable costs, full-scale anaerobic digestion (AD) processes must approach, as much as possible, the potential biogas yield of the organic mixture fed to the biodigesters. In this paper, a new indicator is proposed (the bio-methane yield, BMY), for measuring the efficiency in full-scale AD processes, based on a balance between the biochemical methane potential (BMP) of the input biomass and the residual BMP of the output materials (digestate). For this purpose, a one-year survey was performed on three different full-scale biogas plants, in the Italian agro-industrial context, and the bio-chemical processes were fully described in order to calculate their efficiencies (BMY=87–93%) and to validate the new indicator proposed, as useful and easily applicable tool for full-scale AD plants operators.

On-field study of anaerobic digestion full-scale plants (Part I): An on-field methodology to determine mass, carbon and nutrients balance

The mass balance (input/output mass flows) of full-scale anaerobic digestion (AD) processes should be known for a series of purposes, e.g. to understand carbon and nutrients balances, to evaluate the contribution of AD processes to elemental cycles, especially when digestates are applied to agricultural land and to measure the biodegradation yields and the process efficiency. In this paper, three alternative methods were studied, to determine the mass balance in full-scale processes, discussing their reliability and applicability. Through a 1-year survey on three full-scale AD plants and through 38 laboratory-scale batch digesters, the congruency of the considered methods was demonstrated and a linear equation was provided that allows calculating the wet weight losses (WL) from the methane produced (MP) by the plant (WL=41.949*MP+20.853, R2=0.950, p<0.01). Additionally, this new tool was used to calculate carbon, nitrogen, phosphorous and potassium balances of the three observed AD plants.

Identification of a novel subgroup of uncultured gammaproteobacterial glycogen-accumulating organisms in enhanced biological phosphorus removal sludge

The presence of glycogen-accumulating organisms (GAO) has been hypothesized to be a cause of deterioration in enhanced biological phosphorus removal (EBPR) processes due to their abilities to out-compete polyphosphate-accumulating organisms (PAO). Based on 16S rRNA gene sequences, new members of uncultured gammaproteobacterial GAO (GB) were identified from sludge samples of a lab-scale sequencing batch reactor used for EBPR. The new GB formed a phylogenetic lineage (GB8) clearly distinct from the previously reported seven GB subgroups. Because the new GB8 members were not targeted by the known fluorescence in situ hybridization (FISH) oligonucleotide probes, a GB8-specific FISH probe (GB429) and a new FISH probe (GB742) targeting all eight GB subgroups were designed, and the phenotypic properties of the new GB8 members were investigated. FISH and microautoradiography approaches showed that GB429-targeted cells (GB8) were large coccobacilli (2-4 µm in size) with the ability to take up acetate under anaerobic conditions, but unable to accumulate polyphosphate under the subsequent aerobic conditions, consistent with in situ phenotypes of GB. FISH analyses on several sludge samples showed that members of GB8 were commonly detected as the majority of GB in lab- and full-scale EBPR processes. In conclusion, this study showed that members of GB8 could be a subgroup of GB with an important role in EBPR deterioration. Designs of FISH probes which hybridize with broader GB subgroups at different hierarchical levels will contribute to studies of the distributions and ecophysiologies of GB in lab- or full-scale EBPR plants.

Quasi-Experiments on Process Dynervention Noise Process we Arrived at Anamics

Summary It is often important to develop an understanding of the dynamic properties of a process. However, it is sometimes difficult if not impossible to conduct deliberate experiments on full-scale industrial plants and processes to gain such insight. Fortunately, intentional or inadvertent process changes that occur in the course of normal operation sometimes offer an opportunity to identify and estimate aspects of the dynamic behaviour. We review the theory of dynamic process modelling based on time series intervention analysis and show how this body of theory can be used for an assessment of the dynamic properties of a process. The ideas are accompanied by a detailed example of the study of a large-scale ceramic plant that was exposed to an intentional but unplanned structural change.

Effect of full-scale brewing process on polyphenols in Italian all-malt and maize adjunct lager beers

This paper analyses, in a full-scale industrial process, the flavonoids, non-flavonoids, tannins and non-tannins in all malt worts and in maize adjunct worts and their fate during the main brewing steps. The effect on wort phenols of two different wort separation technologies, a mash filter (Meura 2001) and a lauter tun (Steinecker FVAS 26), were also investigated. The results obtained showed that total phenols are lower in maize-adjunct, than in all-malt worts (542mg/L and 730mg/L, respectively), and that non-tannins are the main phenolic components: 91% of the total in all-malt and 82% in maize-adjunct worts, respectively. The overall brewing process reduces the initial content of total phenols by 50%, and the highest reduction is on tannins and flavonoids. After the brewing process, total phenols in beer were 336.5mg/L in all-malt and 280mg/L in maize adjunct. In moderate drinkers they contribute to 10–20% of the total phenolic daily intake accounting for around 4–8% of the total antioxidant capacity of the diet. As regards the influence of lauter tun and mash filter on phenols, our results showed their great depletion when using lauter tun, and suggested that the brewing process may be adapted in order to overcome the high impact of lauter tun on phenols.

Design and use of group-specific primers and probes for real-time quantitative PCR

Real-time quantitative polymerase chain reaction (qPCR) has gained popularity as a technique to detect and quantify a specific group of target microorganisms from various environmental samples including soil, water, sediments, and sludge. Although qPCR is a very useful technique for nucleic acid quantification, accurately quantifying the target microbial group strongly depends on the quality of the primer and probe used. Many aspects of conducting qPCR assays have become increasingly routine and automated; however, one of the most important aspects, designing and selecting primer and probe sets, is often a somewhat arcane process. In many cases, failed or non-specific amplification can be attributed to improperly designed primer-probe sets. This paper is intended to provide guidelines and general principles for designing group-specific primers and probes for qPCR assays. We demonstrate the effectiveness of these guidelines by reviewing the use of qPCR to study anaerobic processes and biologic nutrient removal processes. qPCR assays using group-specific primers and probes designed with this method, have been used to successfully quantify 16S ribosomal Ribonucleic Acid (16S rRNA) gene copy numbers from target methanogenic and ammonia-oxidizing bacteria in various laboratory- and full-scale biologic processes. Researchers with a good command of primer and probe design can use qPCR as a valuable tool to study biodiversity and to develop more efficient control strategies for biologic processes.

EVOP in Experiments with Mixtures

Evolutionary operation (EVOP) proposed by Box(1957) is a method for continuous monitoring and improvement of a full-scale manufacturing process with the objective of moving the current operating conditions toward the better ones. EVOP in experiments with mixtures consists of screening vital few components and making small changes in the current operating condition by making small increments in the proportion of the screened component. In this paper, how to determine operating conditions in EVOP in experiments with mixtures around the current operating condition is proposed. The proposed methods are illustrated with the simulated data based on the well known flare experimental data described by McLean and Anderson(1966).

The role of colloidal and particulate organic compounds in denitrification and EBPR occurring in a full-scale activated sludge system

The efficiencies of denitrification and enhanced biological phosphorus removal (EBPR) in biological nutrient removal (BNR) activated sludge systems are strongly dependent on the availability of appropriate carbon sources. Due to high costs of commercial compounds (such as methanol, ethanol, acetic acid etc.) and acclimation periods (usually) required, the effective use of internal carbon sources for denitrification is preferred. The aim of this study was to determine the immediate effects of slowly biodegradable substrates on the denitrification capability and phosphate release/uptake interactions for a full-scale biomass process from the "Wschod" wastewater treatment plant (WWTP) in Gdansk (Poland). Since it is hard to distinguish the slowly biodegradable substrate in a direct way, a novel procedure based on batch experiments was developed and implemented. The laboratory experiments were carried out in two parallel, fully automatic batch reactors with the settled wastewater without pretreatment and after coagulation-flocculation. The removal of colloidal and particulate fractions resulted in the reduced observed process rates, such as denitrification, phosphate release and phosphate uptake (under aerobic and anoxic conditions). The reduction ranged from approximately 14% for the anaerobic P release to approximately 46% for the anoxic P uptake.

Rheological characterization of dilute acid pretreated softwood

Large-scale bioethanol production from lignocellulosic biomass will require high solids loading in the enzymatic hydrolysis step. However, slurries of pretreated lignocelluloses are complex fluids due to the fibrous nature, especially at high concentrations of water insoluble solids (WIS). A prerequisite for dealing with transport issues and for developing efficient full-scale processes is a fundamental understanding of the flow properties of pretreated lignocellulose. A comprehensive rheological characterization of dilute acid pretreated spruce has been carried out in this study, accounting for the effects of WIS concentration, particle size distribution (PSD), and the degree of enzymatic hydrolysis. The rheology of pretreated spruce slurries was found to be strongly dependent on the WIS concentration. The storage modulus (G'(LVR)) and yield stress showed typical power-law dependencies on volume fraction and WIS content. Milling of the pretreated material resulted in significantly higher yield stress and viscosity, likely due to narrower PSD, which suggests that the strength of the network of the coarsest fibers determines the rheology of these materials to a large extent. During enzymatic hydrolysis, yield stress and viscosity decreased dramatically, partly due to decreasing WIS content, but possibly also due to changes in fiber properties such as the chemical composition.

Spatial and Temporal Variability in Atmospheric Nitrous Oxide Generation and Emission from Full‐Scale Biological Nitrogen Removal and Non‐BNR Processes

Biological nitrogen removal (BNR) strategies can contribute to atmospheric nitrous oxide (N2O). In the future, as BNR is implemented at more wastewater treatment plants (WWTPs) around the globe, the emission and release of these gases to the atmosphere is expected to increase. This study focused on the quantification of N2O emissions rates and inventory at several WWTPs using a newly developed, U.S. Environmental Protection Agency (Washington, D.C.) (U.S. EPA)-reviewed protocol. Application of the protocol revealed nitrous oxide emissions from aerated zones therein, hitherto not considered in the current U.S. EPA approach to quantifying N20 fluxes from WWTPs. A high degree of diurnal variability in N20 fluxes was measured, which correlated well with diurnal total Kjeldahl nitrogen loadings. In combination, these results point to the diminishing utility of a single emission factor approach to estimate the N2O emissions from WWTPs, which has been followed to date.