Treatment Of High-strength Organic Wastewater Research Articles

Potential of direct granulation and organic loading rate tolerance of aerobic granular sludge in ultra-hypersaline environment

Salt-tolerant aerobic granular sludge (SAGS) technology has shown potentials in the treatment of ultra-hypersaline high-strength organic wastewater. However, the long granulation period and salt-tolerance acclimation period are still bottlenecks that hinder SAGS applications. In this study, “one-step” development strategy was used to try to directly cultivate SAGS under 9% salinity, and the fastest cultivation process was obtained under such high salinity compared to the previous papers with the inoculum of municipal activated sludge without bioaugmentation. Briefly, the inoculated municipal activated sludge was almost discharged on Day 1–10, then fungal pellets appeared and it gradually transitioned to mature SAGS (particle size of ∼4156 μm and SVI30 of 57.8 mL/g) from Day 11 to Day 47 without fragmentation. Metagenomic revealed that fungus Fusarium played key roles in the transition process probably because it functioned as structural backbone. RRNPP and AHL-mediated systems might be the main QS regulation systems of bacteria. TOC and NH4+-N removal efficiencies maintained at ∼93.9% (after Day 11) and ∼68.5% (after Day 33), respectively. Subsequently, the influent organic loading rate (OLR) was stepwise increased from 1.8 to 11.7 kg COD/m3·d. It was found that SAGS could maintain intact structure and low SVI30 (< 55 mL/g) under 9% salinity and the OLR of 1.8–9.9 kg COD/m3·d with adjustment of air velocity. TOC and NH4+-N (TN) removal efficiencies could maintain at ∼95.4% (below OLR of 8.1 kg COD/m3·d) and ∼84.1% (below nitrogen loading rate of 0.40 kg N/m3·d) in ultra-hypersaline environment. Halomonas dominated the SAGS under 9% salinity and varied OLR. This study confirmed the feasibility of direct aerobic granulation in ultra-hypersaline environment and verified the upper OLR boundary of SAGS in ultra-hypersaline high-strength organic wastewater treatment.

Erratum for “Integrated Approach to Treatment of High-Strength Organic Wastewater by Using Anaerobic Rotating Biological Contactor” by Milad Ebrahimi, Hamidreza Kazemi, S. A. Mirbagheri, and Thomas D. Rockaway

Erratum for “Integrated Approach to Treatment of High-Strength Organic Wastewater by Using Anaerobic Rotating Biological Contactor” by Milad Ebrahimi, Hamidreza Kazemi, S. A. Mirbagheri, and Thomas D. Rockaway

Integrated valorization system for simultaneous high strength organic wastewater treatment and astaxanthin production from Haematococcus pluvialis

High-strength organic wastewater, e.g., potato juice wastewater, exerts high stress on the environment. This study proposes an integrated system for simultaneous high-strength organic wastewater treatment and nutrients upcycling for astaxanthin production by the combination of anaerobic processes and microalgae (Haematococcus pluvialis) cultivation. The potato juice wastewater was pretreated by either acidification or methanation. The effluents of both pretreatments achieved higher biomass yields of H. pluvialis compared to cultivation in standard culture media (control). The high acetate and potassium concentrations of the acidification effluents resulted in significantly higher astaxanthin production (24.5–27.9 mg g−1, 3 days) compared to the control (14.7 mg g−1, 12 days) in a shorter period. The integrated system contributed to a final removal efficiency of 51.3–75.8%, 86.5–98.3%, and 69.4–83.4% for COD, phosphorus, and ammonia, respectively. This study presents a promising two-stage process for simultaneous efficient methane and astaxanthin production, as well as remediation of high-strength organic wastewater.

Long-Term Effects of Polyvinyl Chloride Microplastics on Anaerobic Granular Sludge for Recovering Methane from Wastewater.

Polyvinyl chloride microplastics (PVC-MPs) are emerging contaminants affecting biological wastewater treatment processes. However, most of the previous studies mainly focused on their short-term impacts on floc sludge, with little work being conducted to explore their potential effects on more complex anaerobic granular sludge (AGS), which has been widely used for high-strength organic wastewater treatment. In this paper, the long-term effects of PVC-MPs on AGS were investigated via continuous feeding tests that are representative of real wastewater treatment processes. The results of a continuous 264 days test showed that the prolonged exposure of PVC-MPs at 15-150 MPs·L-1 significantly (p = 7.86 × 10-37, 3.44 × 10-43, and 5.29 × 10-46) inhibited the COD removal efficiency of AGS by 13.2%-35.5%, accompanied by a 11.0%-32.3% decreased production of methane and 40.3%-272.7% increased accumulation of short-chain fatty acids (SCFAs). In addition, the PVC-MPs exposure suppressed the secretion of extracellular polymeric substances (EPS), causing AGS and the inside microorganisms to lose the protection of EPS, thereby resulting in granule breakage and decreased cells viability. Aligning with the deteriorated performance, the long-term exposure of PVC-MPs reduced the total microbial populations and the relative abundances of key methanogens and acidogens. A toxicity mechanism assessment revealed that the negative impacts induced by PVC-MPs are mainly attributed to the toxic leachate and excess oxidative stress.

Rapid formation and characterization of aerobic granules in pilot-scale sequential batch reactor for high-strength organic wastewater treatment

This work presents the first attempt in the treatment of high-strength organic wastewater at organic loading rate (OLR) up to 30 kg/m3 d in an aerobic granular sludge sequencing batch reactor. The reactor was operated for 100 days, divided into two main periods according to the applied OLR. In the first period, aerobic granules were cultivated and allowed to stabilize at an OLR of 10.2 ± 2.1 kg COD/m3 d (from the reactor start-up until day 41). In the second period (from day 42 to day 100), the applied OLR was 27.0 ± 3.5 kg COD/m3 d. Stable aerobic granules of average diameter of 1–2 mm dominated the reactor after 30 days, improving the settleability of the biomass. The COD removal efficiency was 98.4 ± 1.1% during the first 45 days of operation. However, after increasing the OLR, the COD removal efficiency decreased drastically to 64.4 ± 13.7% from days 46 to 64. Thereafter, the reactor recovered from the shock load and the removal efficiency increased to 96 ± 2.7% until the end of the 100 days. The effect of COD/N ratio was investigated for the treatment of nitrogen-deficient wastewater. It was shown that under severe nitrogen-deficient conditions (COD/N ratio > 70), the COD removal efficiency was 64.4 ± 13.7%. A COD/N ratio of 25–30 should be attained to ensure that there is no limitation in heterotrophic growth. The results from this study indicate that aerobic granulation can provide a promising high-strength organic wastewater treatment technology.

Superior Antifouling Capability of Hydrogel Forward Osmosis Membrane for Treating Wastewaters with High Concentration of Organic Foulants.

Wastewaters with high concentrations of organic pollutants pose a great challenge for membrane filtration due to their severe fouling propensity. In this study, a hydrogel forward osmosis (FO) membrane is explored for treating wastewaters of high concentration organic pollutants. This FO membrane has an ultrathin hydrogel selective layer, which is highly hydrophilic (water contact angle as low as 18°) and smooth (surface roughness <5 nm). Investigated with typical organic foulants (protein, alginate, humic acid, and oil) of high concentration (2000-20 000 mg/L), this hydrogel FO membrane exhibits remarkably superior antifouling capability, with its water flux decline ratio lower than a quarter that of commercial FO membrane under identical experimental conditions. The foulants on hydrogel membrane surface can be easily removed by simple physical cleaning without any chemical usage. At the same time, this hydrogel FO membrane achieves ∼2 times higher separation efficiency than commercial FO membrane in terms of specific water flux (JW/JS). The antifouling capability and separation efficiency of this FO membrane can be flexibly tailored during selective layer fabrication process. This study opens a new avenue for the treatment of high-strength organic wastewaters by developing a highly antifouling hydrogel-based FO membrane.

Integrated Approach to Treatment of High-Strength Organic Wastewater by Using Anaerobic Rotating Biological Contactor

AbstractThis research assesses the performance and methane production of a novel combined system for treatment of high-strength organic wastewater. The proposed system is composed of a rotating bio...

Research Advances on the High-Strength Organic Wastewater Treatment

With the development of chemical and related industry, the quantity of high-strength organic wastewater is growing, which could cause a bigger threat to human health, so it becomes very urgent and essential to research and develop new applicable wastewater treatment technology. The treatment techniques of high-strength organic wastewater at home and abroad were summarized: physical and chemical methods, biological methods and the combined process. The technological process, characters and principle of every method were introduced. These wastewater treatment technologies have some advantages of completely mineralization and degradation of the pollutants, and low risk of secondary pollution. They also have many disadvantages of complex technological process and higher operating cost. Finally, the direction of the research on two-phase combined process was pointed out.

Development of combined biological technology for treatment of high-strength organic wastewater and results of case studies

Our study group has developed a unique combined biological technology to treat high-strength organic wastewaters from the industries of dyestuff, pharmaceutical, chemical engineering and zymolysis by using the principles of anaerobic ecological niche and bio-phase separation. The study obtained five national invention patents and eight patent equipments. This technology contains four kernel processes - two-phase anaerobic-aerobic process, hydrolysis-acidification-oxidation process, UASBAF-oxidation process, and internal cycling-hydrolysis-oxidation process. Fifteen pilot projects were accomplished in the basins of Tai Lake, Huai River, Liao River and Songhua River, and their total capital investment reached 185.214 million Yuan (RMB). Compared to conventional wastewater treatment technology, the innovative technology is more cost-effective for high-strength organic wastewater treatment, can save capital investment by 15% – 30%, lessen land usage by 20% to 40% and decrease the operating cost by 10% to 25%. The operating cost of treatment per cubic meter industrial wastewater could be below 0.6 to 1.4 Yuan (RMB).

Optimized operational parameters of a pilot scale membrane bioreactor for high-strength organic wastewater treatment

Abstract A pilot-scale test was conducted in a submerged membrane bioreactor (SMBR) for 452 days to treat high-strength traditional Chinese medicine wastewater from two-phase anaerobic digest effluent. This study focuses on the effects of operational parameters on effluent quality of a SMBR. The parameters include shorter hydraulic retention time (HRT), higher influent COD concentration, higher COD loading rate and mixed liquor suspended solids (MLSS). The experimental results demonstrated that when HRT was 5 h and the influent COD was less than 3000 mg L−1, the effluent quality of the SMBR evaluated from its COD content (CODfilt) could meet the accepted Chinese standards for water reclamation; when HRT was 3.2 h and the influent COD was less than 3000 mg L −1, or HRT was 5 h and the influent COD fluctuated between 3000 and 6000 mg L−1, the effluent quality of the SMBR could meet the normal Chinese discharged standard. Statistical analyses showed that CODfilt correlated positively with the COD loading rate. It correlated negatively with the MLSS for MLSS values between 7543 and 13 694 mg L−1. When MLSS was >13 694 mg L−1 it correlated positively with CODfilt. Based on experimental values from SMBR and on values predicted by a simulation model generated using the back propagation neural network (BPNN) theory, the optimum operational parameters for the treatment of a high-strength TCM wastewater were as follows: HRT was 5 h, SRT was 100 day, COD loading rate was

Swim-bed Technology as an Innovative Attached-growth Process for High-rate Wastewater Treatment

Swim-bed technology using the novel acryl-fiber biomass carrier--biofringe (BF) attachment material--demonstrated effective treatment of high-strength organic wastewater with 80% COD removal efficiencies at high volumetric loadings up to 12kg/m3/d with a hydraulic retention time of 3 h. BF material allowed for attachment of large amounts of biomass in a matrix that flexes with the wastewater flow, thus providing a high degree of contaminant-biomass contact in a fully retainable biofilm. As much as 133 g of biomass per meter of BF was retained for an equivalent 13.3 g/l with respect to the BF retention or reaction zone. Limited evidence for nitrification occurred only at low COD loading rates (ca.1.6 kg/m3/d) . In addition, filamentous biomass growth was very heavy at the lower loading rates, but was avoidable at COD loadings of 8kg/m3/d or greater. The levels of extracellular polymers--proteins in particular--in the biofilm were very high compared to levels reported for flocculent or granular sludges. While treatment in this study focused on industrial level applications, the possibility of using this technology in other treatment scenarios involving lower organic loadings was discussed.

Packed-Bed Reactor for Biogas H2S Removal and for Methane-Dependent Effluent Nitrate Removal Applied to High Strength Organic Wastewater Treatment Process.

In a wastewater treatment process consisting of a UASB reactor and aerobic post treatment, excess biogas is produced during the warm season. Methane-dependent nitrate removal using a biogas scrubber would be an efficient way to utilize the excess biogas. The performance of the plastic media-filled packed-bed reactor was examined for biogas scrubbing and methane-dependent nitrate removal. A bench-scale packed-bed reactor was installed in a swine wastewater treatment plant consisting of a UASB reactor and a trickling filter. The biogas from the UASB reactor was supplied from the bottom (3.4-9.4 m d-1), and the trickling filter effluent was spread from the top (9.4-26.1m3 m-2 d-1) . The concentration of H2S dropped from 1200-2500 ppm to less than 2 ppm. The plastic media covered with biofilm were then collected from the reactor and filled into a laboratory scale packed-bed reactor. Inorganic medium containing 40 mg-N l-1 nitrate was spread from the top of this reactor (1.4 m3 m-2 d-1), and gas was supplied from the bottom (25-36.5 m d-1) . The nitrate concentration dropped significantly when CH4 (93%v/v) and O2 (7%v/v) were supplied simultaneously. In contrast, nitrate removal scarcely occurred when only CH4 or He was supplied. These results suggest that simultaneous biogas scrubbing and methane-dependent nitrate removal are possible with the packed-bed reactor.

Temperature Effects on the Performance of an Anaerobic Rotating Biological Contactor

Effects of temperature change in the mesophilic range (20 – 43°C) on the system performance of a four-stage anaerobic rotating biological contactor (AnRBC) for the treatment of high-strength organic wastewater were investigated. In the steady-state condition, the COD removal efficiency increased as the temperature increased in the range of 20 – 35°C. At a temperature of 43°C, the COD removal efficiency was lower than those of at 28 and 35°C but was higher than that of at 20°C. The AnRBC system appears to be an effective treatment process in the mesophilic range under appropriate organic loading rates. A theoretical evaluation on the temperature coefficient indicated that the temperature effects on the performance of AnRBC process are more significant at lower organic loading rates or in the latter stages. In addition, the θ values for the AnRBC process ranged from 1.03 to 1.08 which are in the typical range of some commonly used aerobic processes (1.0–1.10).

Treatment of high-strength organic wastewaters using an anaerobic rotating biological contactor

The removal of high strength organic compounds from the wastewater by an anaerobic rotating biological contactor (AnRBC) was studied experimentally and theoretically. In the steady-state operating condition, the removal efficiencies of soluble COD and BOD could be up to 71% and 76%, respectively, for the organic surface loading rate of 111.4 g COD/m 2·d and organic volumetric loading rate of 13.33 kg COD/m 3·d. A simple model that accounts for the simultaneous convective transport, dispersion in the axial direction, and substrate utilization by the attached biomass was developed to predict the system performance of the AnRBC reactor. Good agreement between model predictions and experimental data was obtained by comparing dimensionless soluble COD concentration profiles measured at the system effluent of earlier stages. The results presented herein are helpful in providing design and operational criteria for a full-scale AnRBC type system.