Traditional Chinese Medicine Wastewater Research Articles

Enhancing effect of conductive materials and rumen microorganisms on the anaerobic digestion performance of a real traditional Chinese medicine wastewater

This work evaluated the effect of different concentrations of conductive materials and rumen microorganisms on the anaerobic digestion (AD) performance of real traditional Chinese medicine (TCM) wastewater. The experiments first determined the optimal organic concentration of 0.25 L/L for the AD system and removed suspended solids from real TCM wastewater to reduce the inhibition effect on methanogenesis. Analysis of the modified Gompertz model showed that the addition of activated carbon, biochar, cow manure, and rumen fluid at doses of 12 g/L, 12 g/L, 12 mL/L, and 125 mL/L, respectively, had the greatest effect on CH4 production, increasing the cumulative CH4 yield by 13.5 %, 10.4 %, 26.8 %, and 32.9 %. Through microbial community and metabolism pathway analyses, the conductive materials promoted direct interspecies electron transfer (DIET) between Clostridium and Methanothrix, and the acetoclastic methanogenic pathway dominated by acetyl-CoA synthase. Rumen microorganisms enhanced AD performance by promoting the growth of hydrogenotrophic methanogens and the abundance of genes dominated by formylmethanofuran dehydrogenase in the hydrogenotrophic methanogenic pathway, illustrating the relationship between microbial community and metabolism pathway. Rumen microorganisms increased CH4 production more than conductive materials in real TCM wastewater. This study helps to better understand the internal mechanisms by which different materials enhance AD performance.

Green treatment of turbid traditional Chinese medicine (TCM) wastewater: Optimization of UF-MD coupling process

Green treatment of turbid traditional Chinese medicine (TCM) wastewater: Optimization of UF-MD coupling process

Natural redox mediator anthraquinone aloe-emodin facilitated the in-situ mineralized γ-FeO(OH) membrane for the removal of tannic acid through photocatalytic-PMS activation

The growing utilization of Traditional Chinese Medicine (TCM) has resulted in an increase in wastewater. Herein, a new kind of organic-inorganic redox mediator membrane by immobilizing γ-FeO(OH) and aloe-emodin(AE) with the characteristic large π-conjugation anthraquinone structure on PVDF membrane was innovatively achieved. AE exhibiting both electron deficiency and redox activity possesses a co-catalyst role in degradation of tannic acid (TA), aiding in the separation of charge carriers through the sequential hydrogenation and dehydrogenation of AE. The removal rates of TA were 92.8 % in the tannic acid solution and 60.3 % in the simulated rhubarb wastewater by the AE-γ-FeO(OH) membrane under PMS+Vis conditions in 45 min. Also, they show a higher recovery of pure water flux and owning good fouling performance. Overall, this current work presents a novel approach for the design and preparation of organic-inorganic photocatalytic composite membrane using readily available natural products for the purification TCM wastewater.

Integrated A/O-MBR–NF process for treating high COD content wastewater from traditional Chinese medicine

Traditional Chinese medicine (TCM) wastewater poses a significant environmental challenge due to its high chemical oxygen demand (COD) and complex components. This study demonstrates a highly effective treatment approach for complex TCM wastewater using a combination of hydrolysis-acidification (HA) pre-treatment, anaerobic-aerobic membrane bioreactor (A/O-MBR), and nanofiltration (NF). Pudilan Xiaoyan Oral Liquid (PDL) wastewater, characterized by high COD (around 5500 mg/L) and baicalin content, served as the model feedstock. The A/O-MBR demonstrated removal rates of 23.6 mg COD g biomass−1 h−1 and 1.0 mg NH3-N g biomass−1 h−1. The combined A/O-MBR-NF process achieved exceptional COD removal exceeding 99 %, significantly reducing the wastewater's environmental impact. Importantly, the treated effluent exhibited no biological toxicity in zebrafish acute toxicity tests, demonstrating the effectiveness of this approach in detoxifying PDL wastewater. Analysis of the A/O-MBR's bacterial community further elucidates the treatment mechanism. This study indicates that MBR treatment for complex TCM wastewater is feasible and holds promising industrial prospects, offering a fresh perspective on the treatment of TCM wastewater with high COD levels.

Hydrodynamic behavior and start-up performance in a periodic anaerobic baffled reactor treating traditional Chinese medicine wastewater for different operation patterns

In order to explore the effect of operation pattern on performance, hydrodynamic behavior and start-up performance including molecular weight distribution (MWD) of soluble organic compounds in a periodic anaerobic baffled reactor (PABR) handling traditional Chinese medicine (TCM) wastewater. Residence time distribution test with tap water in the clean PABR was carried out at a certain hydraulic residence time of 48 h in experiments and in computational fluid dynamics (CFD) simulations, both of which were in good agreement for the ‘every second’ (switching period T = 48 h), the ‘clockwise sequential’ (T = 96 h), and the ‘no switching’ (T = ∞) operation pattern. The CFD model output visualized the hydrodynamic-mass transport, which heavily influenced by operation pattern, successfully inside a PABR. The PABRs run in those three operation patterns were subjected to three successive step changes in average organic loading rate at about 1, 2, 4 and 6 kg COD m−3 d−1 for 12, 24, 24 and 6 d, respectively. Pollutants in the TCM wastewater had the longest time to be digested and degraded within PABR run in the ‘every second’ operation pattern, resulting in a most stable performance among the three. Performance of PABR was consistent with the variation in MWD of soluble organic compounds no matter what the operation pattern was. High- MW species (93–130 kDa) broke down into simpler intermediate- MW solutes (7–56 kDa) by the metabolism of anaerobic flocs sludge mostly in the compartment which contributed most to the total COD removal of PABR. Then, intermediate- MW solutes were mineralized step by step into low- MW solutes (100 Da) and biogas in the follow-up compartments in the sequence of flow pattern.

Hydrodynamic behavior and start-up performance of a periodic anaerobic baffled reactor in an "every second" switching manner treating traditional Chinese medicine wastewater.

Most studies focus on the "clockwise sequential" switching manner for a four-compartment periodic anaerobic baffled reactor (PABR), while the exploration of the "every second" option on the feasibility for real industrial wastewater treatment is rarely reported. Hence, a PABR-treating traditional Chinese medicine wastewater was run continuously in "every second" switching manner with both switching period T and hydraulic residence time of 48 h. Satisfactory start-up performance was achieved during the operation of a climbing average organic load rate at approximately 1, 2, 4, and 6 kg chemical oxygen demand (COD) m-3 d-1 for 12, 24, 24, and 6 days, respectively. The average COD removal was 87.20% after the second lifting of OLR and 89.98% after the third one. Denaturing gradient gel electrophoresis and its cluster analysis showed that the microbial communities in each compartment adapted their structure in response to the periodically changing micro-ecology conditions. Moreover, the residence time distribution test with tap water in the clean PABR was carried out in experiments and computational fluid dynamics (CFD) simulation, both of which were in good agreement. The CFD model output visualized the flow velocity field and hydrodynamic-mass transport inside the PABR. Optimization of operation pattern in PABR including switching manner and frequency depended on both the type of waste being treated and the flexibility of biomass to periodically changing micro-ecology conditions.

Water recovery from cleaning wastewater of traditional Chinese medicine processing via vacuum membrane distillation: Parameters optimization and membrane fouling investigation

With the rapid development of traditional Chinese medicine (TCM) industry, the treatment of TCM wastewater has become an important environmental issue. Among them, TCM processing cleaning wastewater is suitable for recovering high-quality water resources from it due to its low chemical oxygen demand (COD). Compared with pressure driven membrane process, Membrane distillation (MD) can yield highly purified distillate under mild operating conditions. Therefore, this work aims to evaluate the effects of feed temperature, feed flow, osmotic side vacuum degree and membrane material on the treatment of cleaning wastewater from TCM processing. Besides, the fouling of membrane in MD process and the efficiency of chemical cleaning on fouling removal were also investigated. The results show that it is feasible to recover high-quality water from traditional Chinese medicine processing cleaning wastewater by VMD. Compared with feed, COD in permeate decreased by 99%. During the 10 h experiment, the flux of both membranes decreased slightly due to the accumulation of fouling layer on the membrane surface. Chemical cleaning, especially alkali as cleaning agent can effectively remove the fouling layer.

Composite hydrolytic acidification - aerobic MBBR process for treating traditional Chinese medicine wastewater

Traditional Chinese medicine (TCM) wastewater is characterized by high organic content, unstable water quality and quantity and low biodegradability. In this paper, the hydrolytic acidification reactor-aerobic moving bed biofilm (MBBR) process was used to degrade TCM wastewater. Besides, a small pilot study was conducted. The appropriate operating parameters: hydraulic retention time (HRT) of the hydrolytic reactor was 16h, HRT of MBBR was 30h, dissolved oxygen of MBBR was 6mg/L, sludge return ratio of MBBR was 100%. The hydrolytic reactor was started for 25days. MBBR was run in series with the hydrolytic reactor after 24days of separate operation. The start-up of the composite reactor was completed after another 26days. The average removal efficiencies of chemical oxygen demand and ammonia nitrogen were 92% and 70%. The hydrolytic reactor was effective in decomposing macromolecules and MBBR had a strong ability to degrade pollutants through the excitation-emission-matrix spectra. The evolution pattern of the dominant bacterial genera and the surface morphology of sludge were studied by scanning electron microscopy and high-throughput sequencing analysis. It could be seen that the surface morphology of the biological filler was suitable for the growth and reproduction of microorganisms.

Resources recycle of traditional Chinese medicine (TCM) wastewater 2: The UF-FO-MD hybrid system and wetting prevention

Wastewater discharge of traditional Chinese medicine production is a serious threat to the environment in China. This study investigated the effectiveness of the UF-FO-MD hybrid system for resources recycle from the TCM wastewater. Real TCM wastewater was treated with the self-assemble UF-FO-MD hybrid system. Moreover, the natural surfactant rejection and the FO fouling impact were evaluated by separate FO operation with synthetic TCM wastewater, and MD wetting was also assessed. Results show that the UF-FO-MD hybrid system successfully isolated the macromolecular substances, bioactive compounds and water in the TCM wastewater for recovering useful resources. Natural surfactants in the TCM wastewater could be effectively rejected by FO, avoiding the subsequent MD wetting problem which has occurred in our previous study on the resource recovering with the UF-MD hybrid system. However, FO membrane fouling might be an issue affecting the recovery efficiency of bioactive compounds from TCM wastewater. The bioactive compounds could not be completely concentrated due to potential adsorption on the fouling layer.

Study on Advanced Nitrogen Removal and Microbial Community Structure of Traditional Chinese Medicine Wastewater by a Novel System Coupling Anaerobic Sequencing Batch Reactor and Modified Sequencing Batch Biofilm Reactor

To improve the efficiency of nitrogen removal from pharmaceutical wastewater, wastewater from traditional Chinese medicine was treated in an anaerobic sequencing batch reactor (ASBR) combined with a modified sequencing batch biofilm reactor (SBBR). The chemical oxygen demand (COD) and total nitrogen (TN) contents were 3,750 ± 50 mg/L and 210 ± 10 mg/L, respectively. After 99 days of start-up and domestication, the COD, NH4+-N, and TN contents in the effluent were 230 ± 10 mg/L, 1 ± 0.5 mg/L, and 5 ± 3 mg/L, respectively, and the removal efficiencies reached more than 93.5, 99, and 96%, respectively. Among these results, the COD removal efficiency in traditional Chinese medicine wastewater with an ASBR reached more than 85%, and the effluent and raw water were mixed to adjust the C/N ratio in the SBBR influent. The initial operation mode of the improved SBBR was anaerobic–aerobic–anoxic. When the C/N ratio in the influent was adjusted to 5, the simultaneous nitrification and denitrification (SND) in the aerobic section was gradually enhanced, and the endogenous denitrification (ED) in the anoxic section gradually decreased. In conclusion, deep denitrification of the system was achieved only through SND, and the running time of the cycle was shortened from the initial 24 to 4.6 h. High-throughput sequencing analysis showed that the relative abundances of Bacteroidetes and Proteobacteria in the system were 39.69 and 37.34%, respectively. The content of Firmicutes with denitrification in the system was also high, accounting for 5.17%. At the genus level, the bacteria with denitrification functions in the system were mainly Thauera and unidentified_Sphingobacteriales, accounting for 5.67 and 1.66% of the system, respectively. In addition, there was heterotrophic nitrification–aerobic denitrification (HN-AD) activated in the system, including Denitratisoma, Paracoccus, and Pseudomonas. The total relative abundance of these bacteria was 0.612%. Their existence may be one of the reasons for the good effect of SND in this system.

Quinones contained in wastewater as redox mediators for the synergistic removal of azo dye in microbial fuel cells

The present paper aimed to investigate the roles of quinones contained in wastewater and the enhanced effects on microbial fuel cells (MFCs) under different redox conditions. The feasibility of using wastewater rich in quinones to act as co-substrate and redox mediators (RMs) library to strengthen the synergistic removal of azo dye in MFCs was evaluated. The results demonstrated that quinones achieved enhanced effects on electricity generation and COD removal of MFC better at higher current intensity. The addition of pure quinone decreased electron transfer resistance (Rct) of MFCs from 4.76 Ω to 2.13 Ω under 1000 Ω resistance and 1.16 Ω–0.75 Ω under 50 Ω resistance. Meanwhile, higher coulombic efficiency was achieved. Compared with sodium acetate, using quinone-rich traditional Chinese medicine (TCM) wastewater as the co-substrate enhanced the synergistic removal of reactive red 2 (RR2) in MFCs from 79.58% to 92.45% during 24 h. RR2 was also degraded more thoroughly due to the accelerated electron transfer process mediated by RMs. Microbial community analysis demonstrated that the presence of quinone in TCM wastewater can enrich different exoelectrogens under varied redox conditions and thus influenced the enhanced effects on MFC. Metagenomic functional prediction results further indicated that the abundance of functional genes involved in carbohydrate metabolism, membrane transport metabolism, biofilm formation, and stress tolerance increased significantly in presence of RMs. Redundancy analyses revealed that RMs addition was the more important factor driving the variation of the microorganism community. This study revealed the potential effect of quinones as redox mediators on the bioelectrochemical system for pollutants removal.

Resources recycle of traditional Chinese medicine (TCM) wastewater 1: Effectiveness of the UF-MD hybrid system and MD process optimization

TCM wastewater treatment is a significant environmental issue in China. This study investigated the effectiveness of the UF-MD hybrid system on recycling valuable resources in TCM wastewater. Synthetic TCM wastewater was prepared and separated with the self-assemble UF-MD hybrid system. Moreover, the feed temperature (45 °C, 55 °C, 65 °C) and membrane materials' influence on MD performance were also evaluated. Results show that the UF-MD hybrid system is efficient to achieve a complete separation and resources recycle from the TCM wastewater. The MD flux production increased with the increment of feed temperature. However, some bioactive compounds could not be concentrated in MD due to their potential degradation at high temperatures, and membrane wetting might be an issue in long-term operation. Although PP membranes exhibited the highest flux among PP, PTFE and PVDF membranes, considering the wetting and fouling resistance, PTFE membranes would be a better option for long-term MD operation at 65 °C.

Biohydrogen production from traditional Chinese medicine wastewater in anaerobic packed bed reactor system

Three anaerobic packed bed reactors (APBR) packed with activated carbon, maifanite and tourmaline as support material were continuously operated for 165 days to generate hydrogen from traditional Chinese medicine wastewater at different organic loading rates (OLR) from 15.2 to 91.3 g COD L−1 d−1 by changes of hydraulic retention time (HRT) varying from 24 to 6 h. The best performance with hydrogen production rate (HPR) of 7.92 ± 0.27 mmol L−1 h−1 and hydrogen yield (HY) of 3.50 ± 0.09 mmol g−1 COD was achieved for the reactor with tourmaline at OLR of 60.8 g COD L−1 d−1 (HRT = 6 h), followed by activated carbon and maifanite. The main metabolic products for each reactor were found to be acetate and butyrate in the effluent with pH range of 5.6–6.4 and microbial analysis revealed that the dominant communities in all cultures were C. carboxidivoran and C. butyricum, responsible for acetate and butyrate production respectively.

Effects of hydraulic retention time on the performance and microbial community of an anaerobic baffled reactor-bioelectricity Fenton coupling reactor for treatment of traditional Chinese medicine wastewater

The aim of the present paper was to investigate the effects of hydraulic retention time (HRT) on the performance and microbial community dynamics of an anaerobic baffled reactor-bioelectricity Fenton (ABR-BEF) coupling reactor for treating traditional Chinese medicine (TCM) wastewater. The results show that the average removal of chemical oxygen demand (COD) and NH3-N at HRTs of 24 h and 18 h were high (>90% and >70%, respectively), but decreased to about 40% and 30% when operating at 12 h HRT. For the electrical production performance, the maximum power density was 196.86 mW/m3 at a HRT of 18 h. Methanomicrobia was the dominant archaea in the coupling reactor and the relative abundance of Methanothrix and Methanolinea increased with decreasing HRT. For the bacteria, the relative abundance of Planctomycetia significantly decreased with a short HRT; however, Anaerolineaceae was always the dominant bacterial taxa, which could guarantee efficient treatment of TCM wastewater.

Effect of circulation and micro-aeration on sludge characteristics and microbial community in an ABR for treating traditional Chinese medicine wastewater

ABSTRACT The effects of circulation reflux and micro-aeration on the performance of a modified anaerobic baffled reactor (ABR) for treatment of traditional Chinese medicine (TCM) wastewater were evaluated. The characteristics of anaerobic sludge and microbial community structure in the modified ABR were also investigated. The results indicated that with conditions of reflux ratio of 1, reflux ratio of 2, reflux ratio of 2 with micro-aeration, and reflux ratio of 3, the modified ABR achieved an average COD removal efficiency of 90%, 87.7%, 87.8%, and 88.4%, respectively. In addition, the NH3-N average removal efficiency was 45.1%, 50%, 55.9%, and 55.4%, respectively. The analysis of excitation–emission matrix (EEM) fluorescence spectra of soluble microbial products (SMP) and extracellular polymeric substances (EPS) showed that there were tyrosine-like, aromatic protein-like, and coenzyme F420 substances in the sludge. The EPS were analysed by the Fourier transform infrared spectroscopy (FTIR), which showed that aromatic compounds were partially degraded, while the protein and polysaccharide compounds increased in each compartment of the modified ABR. Interestingly, the microbial community of anaerobic sludge analysis results showed that Chloroflexi was the dominant in the first, third and fourth compartments. Meanwhile, Levilinea and Methanothrix were the dominant species in the first and third compartments at the genus level.

Performance of a novel ABR-bioelectricity-Fenton coupling reactor for treating traditional Chinese medicine wastewater containing catechol

In this study, a novel anaerobic baffled reactor-bioelectricity-Fenton (ABR-BEF) coupling reactor, combining an ABR, microbial fuel cell (MFC), and Fenton system, was used to treat traditional Chinese medicine (TCM) wastewater containing catechol. The bio-electrochemical degradation of the catechol reached 99.7% after 8 h at dissolved oxygen (DO) concentration of 4 mg/L in the cathodic chamber. The removal rates of chemical oxygen demand (COD) reached 91.7%, when the ratio rate was 1 and the DO concentration was 4 mg/L. Moreover, the maximum open-circuit voltage and power density of the coupling reactor reached 424.9 mV and 77.1 mW/m3, respectively. According to the PICRUSt analysis, carbohydrate metabolism took up the most abundant function of metabolism and the enrichment of membrane transporters may relieve TCM wastewater toxicity. These results suggest that the ABR-BEF coupling reactor could be applied as an efficient approach to treat TCM wastewater.

Exogenous acyl-homoserine lactones adjust community structures of bacteria and methanogens to ameliorate the performance of anaerobic granular sludge

Quorum sensing (QS) signalling has been extensively studied in single species populations, activated sludge, biofilm and aerobic granular sludge. However, ecological roles of QS in anaerobic granular sludge, particularly in the content of the relationship between QS signalling and microbial community composition and function, have been rarely reported. Herein, five acyl-homoserine lactones (AHLs) molecules were added in the anaerobic granular sludge system for treating traditional Chinese medicine (TCM) wastewater respectively. The results indicated that the introduction of specific AHLs could enhance the abilities of organic matters removal and methanation in anaerobic granular sludge, and meanwhile, exogenous AHLs played an important role to regulate the concentration of EPS. Sequencing analysis indicated that microbial community structures of bacteria and methanogens changed to varying degrees by adding AHLs. This study suggested that exogenous AHLs could play a role in mediating microbial community structure, thereby enhancing the performance of anaerobic granular sludge. The regulatory mechanism of AHLs on community structure was discussed, and a speculative action model was established. Exogenous regulation by selective enhancement of AHLs-mediated QS in anaerobic granular sludge provided an innovative and attractive strategy for strengthening wastewater treatments.

Evaluation of phase separation in a single-stage vertical anaerobic reactor: Performance and microbial composition analysis

In order to explore whether the acidogenic phase and methanogenic phase could be separated vertically into a single-stage anaerobic reactor, a controlled double circulation (CDC) anaerobic reactor was proposed for treating traditional Chinese medicine (TCM) wastewater in this study. The results showed that most of the organic pollutants and refractory were removed in the first reaction area where most of the amount of sludge existed. The organic acids were accumulated in the first reaction area, and larger specific methanogenic activity (SMA) and coenzyme F420 values were found in the second reaction area. Bacterial and archaeal community structures in the two reaction areas of the CDC reactor were analyzed by Illumina MiSeq Sequencing, which revealed that the archaeal community showed larger difference compared with the bacterial community. Differences in the performance and microbial composition of the two reaction areas confirmed that phase separation was implemented in the CDC reactor.

Predicting acute toxicity of traditional Chinese medicine wastewater using UV absorption and volatile fatty acids as surrogates

In this study, the applicability of UV absorbance at 254 nm (UV254) and volatile fatty acids (VFAs) to serve as reliable surrogates to predict acute toxicity of traditional Chinese medicine (TCM) wastewater was investigated. The medicine residues and VFAs were identified as main components of the TCM wastewater, and their individual and joint toxicity assays were operated with luminescent bacteria. The median effective concentration (EC50) values of medicine residues and VFAs were in the range of 26.46–165.55 mg/L and 11.45–20.58 g/L, respectively. The joint toxicity action modes of medicine residues, VFAs and medicine residues-VFAs were identified as additive, additive and synergistic respectively. UV254 and VFAs showed better correlations with acute toxicity according to the correlation analysis, compared with other conventional parameters. The regression model was a good fit for toxic unit (TU50) as a function of UV254 and VFAs according to the stepwise regression method (adjusted R2 = 0.836). Validation of the model to the pilot-scale samples provided satisfactory prediction results in the influent and hydrolysis acidification effluent samples tests, but for EGSB effluent and final effluent samples, the model needed further optimization. Surrogates prediction using UV254 and VFAs provided a valuable and cost-saving tool for rapid or on-line monitoring of acute toxicity of TCM wastewater.

Performance evaluation and hydraulic characteristics of an innovative controlled double circle anaerobic reactor for treating traditional Chinese medicine wastewater

An innovative controlled double circle (CDC) anaerobic reactor modified from the IC reactor was proposed, and the start-up process and performance of treating the traditional Chinese medicine (TCM) wastewater using both “IC reactor” and “CDC reactor” were compared. Through the controlled internal & external circulation system, sludge granulation was performed by inoculating flocculent sludge and a better performance was obtained in “CDC reactor”. COD removal efficiency, methane production and volatile fatty acids (VFAs) in the stable stage of “CDC reactor” were approximately 95%, 0.33L (g COD)−1 and 90mgL−1 respectively, with an organic loading rate (OLR) of 14.67kg CODm−3d−1. Hydraulic characteristics of the CDC reactor with different upflow velocities were analysed using the residence time distribution (RTD) method. The results showed that a higher upflow velocity could lead to a smaller dead space in the CDC reactor, and thus a higher processing efficiency could be achieved. The tanks-in-series (TIS) model was proved to be more adaptive to simulate the flow characteristics of the CDC reactor than the axial dispersion (AD) model under the present experimental conditions. The hydraulic characteristics demonstrated that the good performance of the CDC reactor was ascribed to the improved reactor configuration.