Soy Sauce Wastewater Research Articles

Efficacy and mechanisms of rotating algal biofilm system in remediation of soy sauce wastewater

This study investigated the efficacy of the rotating algal biofilm (RAB) for treating soy sauce wastewater (SW) and its related treatment mechanisms. The RAB system demonstrated superior nutrient removal (chemical oxygen demand, ammonium nitrogen, total nitrogen, and phosphorus for 92 %, 94 %, 91 %, and 82 %, respectively) and biofilm productivity (14 g m−2 d–1) at optimized 5-day harvest time and 2-day hydraulic retention time. This was mainly attributed to the synergistic interactions within the algae-fungi (Apiotrichum)-bacteria (Acinetobacter and Rhizobia) consortium, which effectively assimilated certain extracellular polymeric substances into biomass to enhance algal biofilm growth. Increased algal productivity notably improved protein and essential amino acid contents in the biomass, suggesting a potential for animal feed applications. This study not only demonstrates a sustainable approach for managing SW but also provides insight into the nutrient removal and biomass conversion, offering a viable strategy for large-scale applications in nutrient recovery and wastewater treatment.

Cultivation of Chlorella sp. HS2 using wastewater from soy sauce factory

Incorporation of wastewater from industrial sectors into the design of microalgal biorefineries has significant potential for advancing the practical application of this emerging industry. This study tested various food industrial wastewaters to assess their suitability for microalgal cultivation. Among these wastewaters, defective soy sauce (DSS) and soy sauce wastewater (SWW) were chosen but DSS exhibited the highest nutrient content with 13,500 ppm total nitrogen and 3051 ppm total phosphorus. After diluting DSS by a factor of 50, small-scale cultivation of microalgae was conducted to optimize culture conditions. SWW exhibited optimal growth at 25–30 °C and 300–500 μE m−2 s−1, while DSS showed optimal growth at 30–35 °C. Based on a 100-mL lab-scale and 3-L outdoor cultivation with an extended cultivation period, DSS outperformed SWW, exhibiting higher final biomass productivity. Additionally, nutrient-concentrated nature of DSS is advantageous for transportation at an industrial scale, leading us to select it as the most promising feedstock for microalgal cultivation. With further optimization, DSS has the potential to serve as an effective microalgal cultivation feedstock for large-scale biomass production.

Insight into the formation mechanism of algal biofilm in soy sauce wastewater

Microalgal-biofilm-based wastewater treatment refers to a microalgae-dominated biofilm community in non-axenic systems, in which co-existing bacteria and microbial extracellular polymeric substances (EPS) are crucial for the formation of algal biofilm. However, algae-bacteria consortium biofilm-forming mechanism has rarely been studied in wastewaters including soy sauce wastewater (SW). In this study, we conducted algal biofilm cultivation in raw SW (RSW) and sterilized SW (SSW), and determined the characteristics of algal biofilm and its EPS in the two SW treatments. The results demonstrated that the co-existing bacteria in the algal biofilm system significantly enhanced attached biomass and nutrient removal from RSW, compared to SSW without bacteria. The enhancement may be attributed to EPS excreted by dominated Acinetobacter and Comamonas (both Proteobacteria) in the co-existing bacteria community. The algae-bacteria consortium from algal biofilm in RSW excreted the contents of relatively high tightly bound EPS (TB-EPS) and its proteins (TB-PN), which were conducive to forming the algal biofilm. The high TB-EPS content was related to soluble microbial by-product-like substances (mainly proteins), and its high TB-PN content was mainly caused by the increases in hydrophobic glycine and serine contents for stable biofilm formation. Based on these results, we enhanced our understanding of the formation mechanism of algal biofilm in SW remediation, which provided the theoretical basis for biofilm formation by algae-bacteria synergism.

Enhancing biomass yield, nutrient removal, and decolorization from soy sauce wastewater using an algae-fungus consortium

Soy sauce wastewater (SW), owing to its high levels of nutrients and chromaticity, may cause serious eutrophication if discharged directly into natural water bodies. Microalgae and fungi have great potential for removing nutrients and chromaticity from wastewater and producing value-added biomass. We determined the most robust algal strain, which was isolated from local water bodies, screened in SW, and identified using 18S rRNA gene sequencing analysis. Subsequently, the algal strain and fungal strain, Penicillium sp. were mono- or co-cultured in SW at different inoculum amounts or ratios for achieving maximum biomass yield, nutrient removal, and decolorization from SW. The results suggested that locally isolated NCU-183 (Nanchang University-183) was the most robust algal strain of the four candidates and was identified as Chlorella pyrenoidosa. In monoculture, the maximum biomass yield (2.2 g L−1) and nutrient removal rates (564.7, 20.2, 22.3, and 3.3 mg L−1 d−1 for chemical oxygen demand (COD), ammonium nitrogen (NH4+-N), total nitrogen (TN), and total phosphorus (TP), respectively) were obtained from algal cultivation with an initial dry weight of 0.25 g L−1 (i.e., 5 × 106 cells mL−1) in 100 % SW; the maximum decolorization rate (55.0 PCU d−1) was attained from fungal cultivation at an inoculum density of 103 spores mL−1. Compared to monoculture, the constructed algae-fungus consortium showed higher biomass yield (2.8 g L−1), nutrient removal rates (616.7, 22.8, 25.0, and 4.1 mg L−1 d−1 for COD, NH4+-N, TN, and TP, respectively), and decolorization rate (61.0 PCU d−1) in 100 % SW at an inoculum ratio of algal cells to fungal spores of 5000:1. The consortium biomass with higher protein content (65.3 %) had great potential as a value-added feedstock for animal/fish feed production as compared to the protein-rich C. pyrenoidosa biomass (62.6 %). In conclusion, the algae-fungus consortium showed practical utility for SW remediation and value-added biomass production.

Treatment of soy sauce wastewater with biomimetic dynamic membrane for colority removal and chemical oxygen demand lowering.

Soy sauce wastewater has been produced in soy sauce production and consumption. To reuse this kind of water resource, the chemical oxygen demand (COD), colority should be removed or lowered. Biomimetic dynamic membrane (BDM), GO&Laccase@UF membrane, was prepared by filtering mixture of graphene oxide (GO) and laccase through ultrafiltration (UF) membrane. Compared to UF membrane, the prepared BDM showed great performance in removal of COD and colority, due to the higher laccase activity with existence of GO. The removal rate of colority reached ~80% by one step filtration operation. Moreover, the multiple cycle test evidenced that the value of COD and colority in the permeate after 5 consecutive cycles with the same GO&Laccase@UF membrane still meet the standard for reuse water. This work indicates the promising of BDM for wastewater from food industry.

Recycling nutrients from soy sauce wastewater to culture value-added Spirulina maxima

Soy sauce is one of the most common condiments in East Asian cuisines. Its manufacturing process generates a large amount of organic-rich soy sauce wastewater, which is difficult to treat through traditional processes. In this study, Spirulina NCU-Sm was used to treat soy sauce wastewater and simultaneously produce value-added biomass. The results showed that NCU-Sm grew well in 100% (undiluted) raw soy sauce wastewater (RSW). The maximum biomass yield of NCU-Sm reached 1.984 g/L, and the removal efficiencies of NH4+-N, TN, COD, chromaticity, and salinity in RSW reached 93.86, 81.76, 84.08, 40.93, and 63.08%, respectively. High COD removal efficiency in 100% RSW proved NCU-Sm grew in mixotrophic mode. pH and light spectrum, two major factors affecting growth of soy sauce wastewater-grown Spirulina NCU-Sm, were further studied. When the initial pH of RSW was adjusted to 8, NCU-Sm biomass yield was increased by 11.11%, and the contents of protein, chlorophyll-a, and carotenoid were increased by 8.69, 37.14, 40.40%, and reached 65.57%, 7.57 and 2.78 mg/g, respectively. The removal efficiencies of NH4+-N, TN, and chromaticity in RSW with pH 8 were improved to 99.34, 88.29, 43.18%, respectively. Red light enhanced the photosynthetic oxygen release efficiency of NCU-Sm and increased the carotenoid content of NCU-Sm by 117.95%, reaching 5.95 mg/g. Blue light was adverse to the growth and reduced the protein content of NCU-Sm but significantly increased its chlorophyll-a content to up to 10.99 mg/g. These results suggest that cultivation of Spirulina in soy sauce wastewater serves dual roles in soy sauce wastewater treatment, as well as value-added algal biomass (such as high-quality protein and natural pigments raw materials) production.

Seasonal succession of bacterial communities, metabolic potential and ecological functions in soy sauce wastewater treatment system

Deciphering how bacterial community respond to seasonal variation is beneficial to determine their ecological significances and maintain the performance of wastewater treatment system. Although seasonal succession patterns of bacterial community have been widely investigated, paucity information is known about whether their metabolism and functions have seasonal variations resembling bacterial communities. Here, a combination of 16S rDNA and rRNA amplicon sequencing and qPCR approaches were performed to unravel the response of bacterial community as well as their metabolic potential and functions to seasonal variation. rDNA-derived community exhibited significant seasonal distribution and remarkable divergency with rRNA-derived community, indicating that the structure of the active community was unable to reflect the total community. In addition, environmental factors, such as temperature, total ammonia nitrogen, pH, COD and nitrate concentration, showed different effects on total and active communities. Moreover, quantification of bacterial 16S rDNA and rRNA suggested that bacterial consortia in activated sludge was likely to maintain metabolic potential. Functional traits of them were dominated by chemoheterotrophy, fermentation and nitrogen cycling processes, thus ensuring the stability of this system. Although there were no significant seasonal differences in both DNA and RNA-derived functional compositions, remarkable distinctions were observed between them, indicating that only partial bacteria in activated sludge kept metabolic potential. Collectively, this work provided guidelines for detecting how metabolic potential and functions of bacterial populations in wastewater treatment system respond to environmental factors.

Performance of Aerobic Granular Sludge in Treating Soy Sauce Wastewater at Different Hydraulic Retention Time

Aerobic granular sludge had shown its capability in treating soy sauce wastewater, but its reactor performance, granules properties and biokinetics in different hydraulic retention times (HRT) is still unknown. To ensure the reactor is performed in optimum condition, a judicially selection of HRT is important. The study was conducted in a high and slender column operated according to a sequential batch reactor (SBR) with a sequence of aerobic and anaerobic/anoxic reaction phases. Three different HRTs (8, 16, 24 h) and different anaerobic and aerobic reaction time were evaluated. In the study demonstrated the increase in HRT could reduce the organic loading rate (OLR) as well as biomass yield (Yobs, Y), endogenous decay rate (kd) and overall specific biomass growth rate (µoverall). It was observed a slight increase in the mixed liquor suspended solid (MLSS) and the granules mean size as the OLR decreased. Meanwhile, in the lowest HRT reactor, a narrow diameter range of aerobic granule from 3 to 100 µm was observed due to the development of small and dense granules. The HRT of 24h with aerobic and anaerobic/anoxic reaction time of 3.88 and 7.77h respectively is the SBR’s best performances due to the improvement of the aerobic granular physical properties.

低温 (20 ºC) UASB反応器と常温DHS反応器を組み合わせたシステムによる模擬醤油製造廃水の高負荷連続処理

低温 (20 ºC) UASB反応器と常温DHS反応器を組み合わせたシステムによる模擬醤油製造廃水の高負荷連続処理

Investigation on biomass performance of a submerged membrane bioreactor for treating soy sauce wastewater

Investigation on biomass performance of a submerged membrane bioreactor for treating soy sauce wastewater

Antibacterial Properties of ZnO/Calcium Alginate Composite and Its Application in Wastewater Treatment.

In this study, the antibacterial activities of ZnO with various morphologies were evaluated. A possible mechanism of antibacterial activities of dumbbell like ZnO was proposed based on the microscopic studies of the interaction between bacterial and dumbbell like ZnO, and also based on the antibacterial activity of ZnO enveloped with semi permeable membrane. Monosodium glutamate (MSG) wastewater and soy sauce wastewater were treated by M. purpureus using ZnO/calcium alginate carrier. The attached and suspended biomass in MSG wastewater reached to 228 mg/g and 74 mg/g, while, the attached and suspended biomass in soy sauce wastewater was 130 mg/g and 66 mg/g, respectively. The levels of chemical oxide demand (COD), biological oxide demand (BOD5), SO4(2-) and NH3-N in the treated MSG wastewater were distinctive lower than those detected in the raw wastewater. This ZnO/calcium alginate carrier method could be utilized as an alternative to the traditional anaerobic/aerobic methods in the application of food processing wastewater treatment.

Development and Utilization of Aerobic Granules for Soy Sauce Wastewater Treatment: Optimization by Response Surface Methodology

This study examined some important factors for optimal aerobic granular sludge performance using soy sauce wastewater as a substrate in a lab-scale alternating anaerobic/aerobic sequencing batch reactor (SBR). The SBR was equipped with a circulation process to restrict the concentration gradient of granular biomass during the anaerobic phase. The influence of the circulation rate was investigated together with operation time on the SBR performances. Aerobic granular sludge (AGS) took 60 days to appear and the average diameter was 2.0 mm (with a maximum value of 2.5 mm). Response Surface Methodology (RSM) was used for experimental design, analysis and optimization. The results showed that the maximum COD removal (90%) and good SVI performance of 55.3 mL/g were obtained at the highest value of the operation time (60 d) and at moderate circulation rate (25.2 L/h). The maximum values of MLVSS/MLSS have been found to be 89% at the highest value of the factors (60 d and 36.0 L/h). At optimum point (33.62 L/h of circulation rate and 60 d of operation time), the amount of COD removed, MLVSS/MLSS and SVI were 86.5%, 88.8% and 58.6 mL/g, respectively.

Performance of aerobic granular sludge at variable circulation rate in anaerobic-aerobic conditions.

Aerobic granular sludge (AGS) has been applied to treat a broad range of industrial and municipal wastewater. AGS can be developed in a sequencing batch reactor (SBR) with alternating anaerobic-aerobic conditions. To provide anaerobic conditions, the mixed liquor is allowed to circulate in the reactor without air supply. The circulation flow rate of mixed liquor in anaerobic condition is the most important parameter of operation in the anaerobic-AGS processes. Therefore, this study investigates the effect of circulation rate on the performance of the SBR with AGS. Two identical reactors namely R1 and R2 were operated using fermented soy sauce wastewater at circulation rate of 14.4 and 36.0 l/h, respectively. During the anaerobic conditions, the wastewater was pumped out from the upper part of the reactor and circulated back into the bottom of the reactor for 230 min. A compact and dense AGS was observed in both reactors with a similar diameter of 2.0 mm in average, although different circulation rates were adopted. The best reactor performance was achieved in R2 with chemical oxygen demand removal rate of 89%, 90% total phosphorus removal, 79% ammonia removal, 10.1 g/l of mixed liquor suspended solids and a sludge volume index of 25 ml/g.

Preparation of ZnO Nanowire Using Sludge from Wastewater Treatment

In this study, we present the synthesis of ZnO nanowire by hydrothermal process through reutilization of sludge from soy sauce wastewater electrochemical treatment. The influences of floc content and caramel pigment concentration on the morphologies of ZnO were studied. The products were characterized by XRD and SEM. The results showed that ZnO powder was of hexagonal wurtzite structure and well crystallized with high purity. Floc content and caramel pigment concentration played an important role in the final morphologies of ZnO nanowires. On the basis of these results, a possible growth mechanism for the formation of ZnO nanowires was described. These findings not only may contribute to control the synthesis of ZnO, but also present a novel method for the disposal of wastewater treatment sludge.

Photofermentative hydrogen production using Rhodobium marinum from bagasse and soy sauce wastewater

A marine photosynthetic bacterial consortium was studied for its capability of hydrogen production using treated soy sauce wastewater and bagasse as a sole carbon source. Denaturing gradient gel electrophoresis (DGGE) profiles showed that the dominant bacterium in the bacterial consortium was Rhodobium marinum. The effects of treatments of soy sauce wastewater were tested for hydrogen production. The feedstock treatments included dilution, sterilization, neutralization and by adding sodium bicarbonate and yeast extract. The maximal cumulative hydrogen production was achieved up to 200 ± 67 mL H2 in the medium containing soy sauce and 41 ± 16 mL H2 from the hydrolyzed bagasse as substrate.

Effect Factors of Soy Sauce Wastewater Treatment by Allure-type Wastewater Treatment Equipment

Allure-type wastewater treatment equipment is a typical anaerobic-aerobic treatment technology for soy sauce wastewater treatment. Chromaticity material is one of the factors affecting the treatment effect except salinity, nutrients, and dissolved oxygen. Part of COD comes from chromaticity material, too high chromaticity volume load inhibit metabolism of aerobic microorganisms, and resulting COD was not degraded in aerobic process.