Starch Wastewater Treatment Research Articles

Significant enhancement of biomethane recovery in up-flow anaerobic sludge blanket reactor treating starch wastewater through oyster shells conditioning

The up-flow anaerobic sludge blanket (UASB) reactor for treating starch wastewater exhibits poor resistance to organic loading rate shocks and low efficiency in biomethane recovery. This study proposed a solution to address this issue by using oyster shells as an alternative conditioner. Results indicated that the UASB reactor with oyster shells conditioning exhibited a significant increase in methane production from 243 to 435 mL/g-chemical oxygen demand (COD)removed, as the organic loading rate increased from 2.5 to 7.1 kg-COD/(m3·d). This value surpassed that of the control reactor, which experienced a sharp decline in performance. Furthermore, it also exceeded the majority of reported methane yields ranging from 150 to 330 mL/g-CODremoved. The pH adjustment and additional supply of carbon dioxide from oyster shells was primarily responsible for the substantial increase in methane production. Moreover, oyster shell conditioning also resulted in improvements in specific methanogenic activity, extracellular polymeric substances protection, and settling capacity of anaerobic granular sludge, as well as the enrichment in Methanosaeta abundance, and strengthening of methanogenic functional activity. All these factors contributed to the successful methanogenesis of starch wastewater in UASB reactor through oyster shell conditioning. These findings highlighted the potential of using oyster shells as a favorable conditioner for optimizing UASB treatment of easily acidified wastewater (e.g., starch wastewater), which presented promising practical applications.

Treatment of Starch Wastewater by α‐Amylase Immobilized on Silica Infused Magnetite Nanoparticles for Maltose Syrup Preparation

AbstractCasein decorated silicainfused magnetite (Fe3O4‐SiO2) nanoparticles are employed to immobilize commercial α‐amylase, where glutaraldehyde serves as a cross linker. The optimal concentration of variables, such as casein (1.4%w/v), Fe3O4‐SiO2 (106 µl), glutaraldehyde (55µl) and amylase (1 mg/ml) are defined by a Box Behnken design. The binding of casein, glutaraldehyde and enzyme over the nanoparticles are further confirmed structurally by fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA). The loading capacity is 37 µg amylase over 1 µg of silica infused magnetite nanoparticles. The optimum pH for the catalysis of soluble and immobilized amylases is the same, i.e. pH 7. However, the pH range for catalysis is improved upon immobilization. The temperature optimum of soluble and immobilized amylases are 40 and 70 °C, respectively. The amylase stability is improved upon immobilization, as shown by enhanced half‐life and reduced deactivation rate constant. The immobilized amylase is used for 17 consecutive cycles with retention of 52% of the residual activity. The immobilized amylase produces high maltose syrup using the industrial wastewater containing corn starch. The ISO 5377 protocol determines dextrose equivalence values to be 36% and 24% during cycle 1 and cycle 2, respectively. The findings point out its possible commercial use.

Efficient treatment of starch wastewater through metallic-starch complexes and magnetic flocculation

Starch wastewater poses significant environmental harm, necessitating the implementation of effective treatment methods. The current starch wastewater treatment methods have some drawbacks, such as limited application scenarios, complicated process and insufficient purification efficiency. This study focuses on the purification of starch wastewater through metallic-starch complexes (MSCs) and magnetic flocculation. Metal ions (Fe3+, Pb2+ and Al3+) were added to interact with starch and coagulate, forming MSCs, in which the O6 atom of the branched chain methanol most likely to interact with metal ions. Then, the magnetic particles, sintering dust (SD), was utilized to adsorb the MSCs and form magnetic flocs, facilitating their rapid settlement under an external magnetic field. The purification experiments were aimed at a high-concentration starch wastewater with COD concentration of 12,000 mg/L, and the results demonstrated the metal ions could effectively coordinate with starch and form MSCs, achieving a COD removal rate of over 90%. Meanwhile, to address the challenge of difficult settlement of MSCs, the addition of SD induced the magnetic flocculation with MSCs through Van der Waals force and electrostatic force, which effectively reduced settling time and decreased sedimentation layer thickness. The combined use of MSCs and magnetic flocculation achieved efficient purification of starch wastewater.

Determination of biokinetic coefficients of an aerobic system for potato starch removal

This study presents an aerobic laboratory scale-reactor completely mixed performance for starch wastewater treatment. The reactor was operated for 119 days divided into 5 operational phases which included the start-up and the variation of cell-residence time. In order to determine the biokinetic coefficients for starch removal, the cell-residence time was varied between 20 to 4 days, and the system operation was set hydraulic retention time of 24 hours with a completely mixed reactor setup. The chemical oxygen demand concentration was 1000mg/L in the inflow of the reactor and dissolved oxygen remained above 2mg/L. In this experimentation time, the parameters such as pH, chemical oxygen demand (in the influent and effluent), dissolved oxygen and Mixed liquor suspended solids were monitored. The calculation of biokinetic constants was done by an approximate method, using the graphical Lineweaver-Burk method. The biokinetic coefficients determined were for Maximum substrate removal rate , Half saturation rate constant or affinity constant ( sludge yield coefficient (Y), and Microbial decay or indigenous respiration rate . The results showed that Y, , and ( were in the range of 0,3- 0,7 mgSSV/mgBOD5, 2- 8 Day1 and 40-120 mg/L (COD- BOD5), respectively. Values of the coefficients were within the range of those reported for conventional activated sludge processes.

One-step co-cultivation and flocculation of microalgae with filamentous fungi to valorize starch wastewater into high-value biomass

A novel method of one-step co-cultivation and harvesting of microalgae and fungi, for efficient starch wastewater treatment and high-value biomass production was developed. By combination of Aspergillus oryzae and Chlorella pyrenoidosa, nutrients in wastewater could be converted to useful microbial biomass, while the wastewater was purified. Moreover, the microalgae C. pyrenoidosa could gradually be encapsulated in fungal pellets which promoted the biomass harvesting. The free algal cells could be completely harvested by fungal pellets within 72 h. The synergistic effects between them greatly improved the removal efficiencies of main pollutants as the removal efficiency of COD, TN, and TP reached 92.08, 83.56, and 96.58 %, respectively. In addition, the final biomass concentration was higher than that of individual cultures. The protein and lipid concentration was also significantly improved and reached 1.92 and 0.99 g/L, respectively. This study provides a simple and efficient strategy for simultaneous wastewater treatment and high-value biomass production.

Treatment of starch‐rich wastewater using fly ash‐based low‐cost tubular ceramic membrane

AbstractImplementation of fly ash‐based ceramic tubular membranes in starch wastewater treatment can be considered as a cost‐effective approach towards treating huge quantities of wastewater generated in starch industries. The membrane used in this work possesses excellent chemical and mechanical stabilities and has average pore size of 0.133 μm and porosity of (40.17 ± 1.04)%. The permeate produced by treating wastewater from all three starch sources, namely corn, wheat, and rice, was absolutely free of total suspended solids and turbidity and contained slight chemical oxygen demand, which is under permissible limit for discharge into natural water bodies as prescribed by Central Pollution Control Board (CPCB), India. Besides, the experiments conducted revealed that along with applied pressure, cross‐flow velocity and size of starch granules can also play pivotal roles in determining the extent of flux decline. Moreover, the estimated cost of the fabricated membrane is 250.00 USD/m2, signifying that the membrane has affordability for being implemented in starch processing industries of all scale.

Efficient Treatment of the Sweet Potato Starch Wastewater by Enhanced Flocculation–Coagulation of Environmentally Benign Materials

Efficient Treatment of the Sweet Potato Starch Wastewater by Enhanced Flocculation–Coagulation of Environmentally Benign Materials

Mixing starch wastewaters to balance nutrients for improving nutrient removal, microalgae growth and accumulation of high value-added products

Unbalanced nutrients limited the starch wastewater (SW) treatment and nutrient recovery by microalgae. The higher carbon content in SW resulted in a nutritional imbalance for the growth of microalgae. While, the anaerobic wastewater with less organic content made up for this shortcoming. Mixing the two could improve the C/N ratio of wastewater, promoted the synthesis of microalgal biomass and the purification effect of wastewater. In this study, five species of microalgae (Chlorella sp. HQ, Scenedesmus sp. LX1, Tribonema sp., Anabaena sp. and Anabaena flos-aquae) suitable for growth in SW were compared, and the optimal microalgae (Chlorella sp. HQ) was selected out to be cultured in corn SW (CSW), modified SW (MSW), anaerobic wastewater (AW) and their mixtures. The results showed that the subculture biomass of Chlorella sp. HQ in CSW increased from 2.15 to 2.61 ​g/L. In mixed wastewater, CSW ​+ ​MSW ​+ ​AW improved the biomass of microalgae with CSW as a culture medium by 0.3-fold (to 2.79 ​g/L), and the algal density was as high as 1.57 ​× ​107 ​cells/mL. In addition, 75.49% of chemical oxygen demand (COD), 62.00% of total nitrogen (TN), 76.47% of total phosphorus (TP), and 56.57% of ammonia nitrogen (NH4+-N) were removed by microalgae. The yields of lipids, polysaccharides, and proteins were 1.34, 1.76, and 1.09 times (0.90 ​g/L, 0.30 ​g/L, and 1.19 ​g/L) that of CSW as a culture medium, respectively. These results implied that mixing different sections of SWs to balance nutrients levels for microalgae cultivation and wastewater treatment could be an efficient and economical mode.

Improved separation performance of SS fiber nonwoven felt by the coating of a non-isotropic porous SS membrane layer

With excellent mechanical properties, large porosity, and permeability, stainless steel (SS) fiber nonwoven felt has outstanding application advantages in high-temperature filtration and purification. However, the pore size of the SS nonwoven felt, which is directly determined by the diameter of the produced fiber stacked inside, usually varies from tens of microns to several microns. Low filtration accuracy greatly limits its application in the fields of fine separation and purification. In this study, the separation performance of SS fiber nonwoven felt was improved by the coating of a non-isotropic porous SS membrane layer via the immersion precipitation phase inversion-sintering method. The effects of sintering temperature on pore structure, surface wettability, separation performance, and mechanical properties of the coated SS nonwoven felt were characterized by scanning electron microscope (SEM), water contact angle (WCA), water permeability, and tensile test, respectively. The results suggest that with the increase of sintering temperature from 1000°C to 1200°C, both porosity and pore size reduce gradually. The WCA value shows an increase from 31.4 to 62.3° and pure water flux shows a corresponding decrease from 2562 to 889 L . m−2 . h−1. The sintering temperature has a negative effect on the mechanical strength of the coated SS fiber nonwoven felt, which is mainly determined by the mechanical properties of the sintered SS fiber nonwoven felt substrate. The coated SS fiber nonwoven felt exhibits a long-term durable separation performance even after frequent combined physical washing and chemical cleaning when applied in the treatment of potato starch wastewater.

An analysis of performance of an anaerobic fixed film biofilter (AnF2B) reactor in treatment of cassava wastewater

The cassava starch wastewater contains organic materials (as BOD, COD) in high concentrations so it has the potential to cause pollution in the aquatic environment. Several methods of cassava starch wastewater treatment have been used to reduce the concentration of organic matter (pollutants) in cassava starch wastewater, including Activated Sludge, Stabilization Pond, Anaerobic-Aerobic filter process. However, various studies continue to be carried out to get higher processing efficiency on the factors that influence it. Several factors influence the efficiency of wastewater treatment processes, including the type and origin of decomposing microorganisms, hydraulic residence time (HRT), organic load rate (OLR), process design, pH, and temperature. The research aimed to evaluate the performance of the AnF2B reactor in treating cassava starch wastewater, in which the reactor performance is shown by changes in organic matter removal (COD removal) and biogas production. The research is conducted using 3 types of AnF2B reactors wherein each AnF2B reactor contains a bee nest-shaped bio-filter as a growth medium for the consortium of indigenous bacteria. The AnF2B reactor operates in anaerobic conditions with a set temperature of 29–30 °C and a pH of 4.5–7. In each AnF2B reactor, cassava starch wastewater is fed with different OLR so that each reactor has an HRT of 5, 6, and 7 days. The concentration of COD at the influent and effluent of the reactor was measured and the biogas was produced using the APHA standard method. The results showed that the AnF2B reactor had a satisfactory performance in COD removal and biogas production, which at HRT: 6 days and OLR of 1.72 g/L·day found that the maximum COD removal was 98 % and the volume of biogas of 4.8 L/L·day was produced on the 12th day

Improved stability of up-flow anaerobic sludge blanket reactor treating starch wastewater by pre-acidification: Impact on microbial community and metabolic dynamics

Poor processing stability has been cited as the fatal shortcoming of the up-flow anaerobic sludge blanket (UASB) reactor treating starch wastewater (SW). In this study, the SW treatment performance in a one-stage UASB reactor and a pre-acidification equipped UASB process were evaluated together with the microbial dynamics. The results revealed that the pre-acidification provided improvements in terms of the substrate utilization diversity and the stability of the microbial community structure on the UASB reactor. Anaerolineaceae/Methanosaeta was the core functional microbiota in the pre-acidification equipped UASB reactor, indicated the superior abilities on the acetogenic methanogenesis of granules. The genus of Methanobacterium, a hydrogenotrophic methanogen was dominant in the archaeal community in the one-stage UASB reactor. The granules performed very strong hydrogen affinity in methane production, a small amount of propionate was detected in the effluent. These were abnormal, which suggested the high hydrogen turn-over rate in the one-stage UASB reactor.

Identification of sulfate-reducing and methanogenic microbial taxa in anaerobic bioreactors from industrial wastewater treatment plants using next-generation sequencing and gene clone library analyses

An understanding of microbial communities present in anaerobic bioreactors can strongly facilitate the development of approaches to control undesirable microorganisms, such as sulfate-reducing bacteria (SRB), in the system. In this study, overall microbial communities present in anaerobic bioreactors from seven industrial wastewater treatment plants (including food, pulp and paper industries) were investigated using 16S rRNA gene amplicon sequencing (MiSeq, Illumina). The dominant methanogens identified in the anaerobic bioreactors treating industrial wastewater were Methanobacterium and Methanosaeta; Methanospirillum was a predominant methanogen in the anaerobic sludge digester. Hydrogenotrophic and acetoclastic methanogens were detected at similar relative abundances in the anaerobic covered lagoons treating starch wastewater, whereas hydrogenotrophic methanogens were the predominant methanogens present in the sludge digester. SRB communities were further investigated using dsrB gene clone libraries. The results indicated the presence of SRB, such as uncultured Desulfobulbus sp., Syntrophobacter fumaroxidans, Syntrophorhabdus sp. PtaB.Bin027, and Desulfovibrio fructosivarans JJ. Incomplete-oxidizing SRB were the predominant SRB in all of the anaerobic bioreactors treating wastewater. In contrast, similar relative abundances of complete and incomplete-oxidizing SRB were observed in the sludge digester. The results of this study can further facilitate the development of SRB-controlling strategies to improve the efficiency of wastewater treatment.

Treatment of potato starch wastewater by dual natural flocculants of chitosan and poly-glutamic acid

Starch wastewater treatment required extensive optimization because of its high concentrations of organic compounds and concentrated emissions. An environmental friendly dual flocculant, composed of cationic chitosan and anionic poly-glutamic acid, was investigated. Initial mechanistic studies involving independent injections of chitosan and poly-glutamic acid revealed their primary mechanisms of charge neutralization and bridging respectively. The highest removal rates of turbidity by chitosan and poly-glutamic acid were 90.1% and 91.8%. Dosing pattern studies showed that initial chitosan dosing provided the highest removal rate and widest effective pH range. Mechanistic studies using zeta potential and floc measurements, confirmed that chitosan neutralized negative charges, while long-chained poly-glutamic acid aggregated particulates. The effects of wastewater quality storage time, compound ratio, and total dosage were studied, with optimization at 0 h, 1:1, and 80 mg L−1, which outperformed traditional flocculants polyaluminium chloride and polyferric sulfate. The removal rates of chemical oxygen demand, total nitrogen, total phosphorus and turbidity were 44.8, 53.4, 28.1, and 98.3%. The sediment was detected containing 95% of organic matters and 5.6% of total nutrients making it an excellent organic fertilizer. This dual system is promising in starch wastewater treatment and resource recovery considering its eco-friendly and effective flocculation performance.

OPTIMIZATION OF BIOGAS PRODUCTION FROM CO-DIGESTION OF WASTE ACTIVATED SLUDGE AND MODIFIED TAPIOCA STARCH SLUDGE

Waste activated sludge (WAS) obtained from a modified tapioca starch wastewater treatment plant has potential for use as feedstock for biogas production. However, it has a very low C/N ratio of 4.3, leading to a low methane yield. Co-digestion of WAS with starch sludge (SS) can potentially provide balanced nutrients and can enhance biogas production. The results from a biochemical methane potential (BMP) test showed that using WAS as a single feed stock provided a low biogas production at 80 L/kg TVSadded. In co-digestion, the addition of 30% and 50% SS increase the biogas yields by as much as 150 and 209 L/kg TVSadded, respectively. However, the addition of 70% SS reduces the biogas yield to as low as 117 L/kg TVSadded. The result also showed that the optimum condition for biogas production is achieved at 2% TVSadded of mixed WAS and SS (1:1) with a desired C/N ratio of 23.56. The increase in % TVSadded of the mixed feedstock resulted in a reduction of the biogas yield. The co-digestion of WAS and SS (1:1) also improved the rate of digestion and enhanced the system stability. TVS removal efficiency of the mixed WAS and SS was 41.44% higher than the efficiency when using WAS alone. Moreover, the result of continuous stirred tank reactor (CSTR) confirmed that the co-digestion ratio of WAS:SS (1:1) can enhance biogas yield and methane yield at 301 and 142 L/kg TVSadded, respectively at retention time of 11 days.

Measurements of Bacterial Community and Biodiversity from Activated Sludge for a Wastewater Treatment Containing Starch

This study analyzes the microbial community and diversity composition of activated sludge in anoxic/oxic (A/O) treatment systems at different operation stages using Illumina MiSeq high-throughput sequencing to investigate the microbial community structure and diversity in activated sludge for starch wastewater treatment. The experimental results showed that the microbial community structure of activated sludge for starch production wastewater treatment in A/O systems was quite stable under the same wastewater condition, and that the dominant bacteria of the activated sludge were Proteobacteria, Bacteroidetes, Chloroflexi, Firmicutes, and Actinobacteria. The most important dominant bacterial group was Proteobacteria (45.66%-66.30%), of which γ-subclass bacteria were the main member and occupied 36.38%-66.65%. The proportion of Sphingobacteria, the main member of the Bacteroidetes, decreased when the sludge settling performance was better, but the proportion of Anaerolineae, the main member of Chloroflexi, increased significantly when the sludge sedimentation performance was better. These changes may have been closely related to the behavior of sludge settleability. There were a large number of functional bacteria in the activated sludge, which played an important role in the degradation of pollutants and in nitrogen and/or phosphorus removal.

Starch wastewater treatment technology

Several methods of starch wastewater treatment in recent years, including physical method, physical-chemical process, biological method and combined process method, were reviewed. The advantages and disadvantages of these methods are analyzed, and the development and research direction of these methods are prospected.

Design and operation effect of corn starch wastewater treatment project

The corn starch wastewater was treated by the combination of “IC anaerobic + two-stage AO biochemical + modified Fenton”. The design parameters and treatment effects of the main construction sections of the project were introduced. The operation results of the project show that the combined process has a good treatment effect on corn starch wastewater. In the case where the average concentration of COD in the influent water is 17640 mg/L, the average concentration of NH3-N is 91.1 mg/L, and the average concentration of TN is 1266 mg/L. The average concentration of the COD, NH3-N and TN in the effluent water after treatment are 36mg/L, 1.2mg/L and 11.6mg/L, respectively, which meets the design standard requirements. The process control method of using some high-concentration organic wastewater beyond the anaerobic section can achieve the standard treatment of total nitrogen without the need of external supplementary carbon source, which has significant economic benefits.

Treatment of tapioca starch wastewater with ozonation and adsorption

In this research, removal of cyanide and COD in tapioca starch wastewater by ozonation and adsorption using GAC examined. The method effectiveness evaluated from percentage of cyanide and COD degradation and ozone mass balance. Effect of degradation method, pH and ozone dose was determined using synthetic wastewater with initial cyanide concentration of 30 ppm and COD concentration of 1000 ppm. Using ozonation adsorption with pH 10 and ozone generation rate of 303 mg O3/h, 91.75% cyanide and 68.94% COD from synthetic wastewater was removed in 1 hour. Tapioca starch wastewater with cyanide concentration of 8.5 ppm and COD concentration of 4625 ppm treated using the same operating condition. Using this method, 87.06% cyanide and 43.23% COD was removed.

Cassava Wastewater Treatment by Coagulation/flocculation Using Moringa Oleifera Seeds

The present study evaluated the efficiency of starch wastewater treatment through coagulation/flocculation using extracts of Moringa oleifera (M.O.) seeds as a natural coagulant. The experiments were performed following a Rotatable Central Composite Design (RCCD). The studied variables were: M.O. concentration and sodium chloride (NaCl) solution concentration. The response variables analysed were: Turbidity, Apparent Colour, COD and Cyanide Ion. The operational conditions optimized by the statistical program were: M.O. concentration of 2,484 mg L-1 and saline concentration of 0.9 mol L-1. Under these conditions the removal estimates are 89.16 % (turbidity), 54.43 % (apparent colour), 66.39 % (COD) and 9.9 % (cyanide ion).

Cassava Wastewater Treatment in Fixed-Bed Reactors: Organic Matter Removal and Biogas Production

The process of cassava starch extraction is associated with the generation of a large volume of liquid wastes from root washing and starch extraction (5 to 7 L.kg-1root). In this context, the objective of this study was to evaluate the treatment of cassava starch wastewater in a horizontal anaerobic fixed bed reactor to the removal of organic matter and generation of biogas. For this purpose, two fixed bed reactors filled with two different types of support materials were used: bamboo rings and flexible PVC rings. The reactors were constructed in polyvinyl chloride (PVC) with 90 cm length and 15 cm diameter. The working volume of R1 (bamboo as support material) and R2 (PVC as support material) were 6.0 and 8.0 L, respectively. In the operation of the reactors, 13 assays (A1 to A13) were carried out with an increase in the organic loading rate (OLR: 1.7 to 15.0 g COD.L-1.d-1) and a decrease in the hydraulic retention time (HRT: 4.0 to 0.8 days). Biogas production followed a similar pattern in both reactors. The highest biogas productions of 1.5 L.L-1.d-1 (R1) and 1.1 L.L-1.d-1 (R2) were verified in the assay 6 in which were applied highest affluent concentration (15,122 mg.L-1), intermediates organic loading rate (5.6 g.L-1.d-1) and hydraulic retention time (2.7 d). The removal of COD increased with the increase of OLR resulting in COD removal values of up to 99%. Total solids removal efficiencies of 79 and 87% were achieved in R1 and R2, respectively. In both reactors, the contact surface of bamboo (132 m2.m-3) and PVC (191 m2.m-3) supported biomass attachment even in highest OLR (15 g.L-1.d-1) and low HRT (0.8 d). The both support material provided conditions to the reactors withstand the variations and reestablish the equilibrium after possible hydraulic and load shocks, constituting a robust system for the treatment of cassava starch wastewater. In these conditions the COD and solids removal remained satisfactory. After a 450-day reactor running, no changes were observed in the composition and structure of the support material, an indication that bamboo and PVC are possible cheap and efficient alternatives for biomass immobilization.