High Strength Industrial Wastewater Research Articles

Microbial Selection for the Densification of Activated Sludge Treating Variable and High-Strength Industrial Wastewater

This study investigates the densification/granulation of activated sludge with poor settleability, treating real industrial wastewater from a tank truck cleaning company. The wastewater is low in nutrients, acidic in nature, and high and variable in chemical oxygen demand (COD, ranging from 2770 mg·L−1 to 14,050 mg·L−1). A microbial selection strategy was applied to promote slow-growing glycogen-accumulating microorganisms (GAO) by the implementation of an anaerobic feast/aerobic famine strategy in a sequencing batch reactor (SBR). After 60 to 70 days, the uptake of carbon during the anaerobic phase exceeded 80%, the sludge morphology improved, and the sludge volume index (SVI) dropped below 50 mL·g−1. 16S rRNA gene sequencing showed the enrichment of the GAOs Defluviicoccus and Candidatus Competibacter. Stable sludge densification was maintained when using a constant organic loading rate (OLR) of 0.85 ± 0.05 gCOD·(L·d)−1, but the sludge quality deteriorated when switching to a variable OLR. In view of the integration of densified/granular sludge in a membrane bioreactor configuration, the filtration properties of the densified SBR sludge were compared to the seed sludge from the full-scale plant. The densified sludge showed a significantly lower resistance due to pore blockage and a significantly higher sustainable flux (45 vs. 15 L·(m2·h)−1).

Enhanced Pretreatment of Natural Rubber Industrial Wastewater Using Magnetic Seed Coagulation with Ca(OH)2

The efficiency of magnetic seed coagulation (MSC) with pH adjustment by NaOH and Ca(OH)2 as a pretreatment for high-strength natural rubber industrial wastewater (NRIWW) was compared in this study. The high content of suspended solids (SSs) and other inhibitory substances of NRIWW is a primary issue which affects its subsequent secondary and tertiary treatment processes. The MSC process with polyaluminum chloride (PAC), anionic polymer (polyacrylamide—PAM)), and magnetic seeds (MS) (ferric oxide (Fe3O4)) was proven to be a cost-effective pretreatment of NRIWW, and Ca(OH)2 showed improved pretreatment performance, with turbidity, COD, and TSS removals of 95%, 56%, and 64%, respectively. Sedimentation was enhanced from 30 min by conventional coagulation to less than 5 min by the MSC. The organic components of NRIWW reacted with MS to generate Fe–OH/Fe–OH+ linkages through processes of surface complexing and hydrogen bonding. According to fractal analysis, the MSC process optimized with Ca(OH)2 produces less complex flocs that are uniform and densely packed. Additionally, MS served as an adsorbent and promoted the development of magnetic flocs by boosting their density and size. MSC with pH adjustment by Ca(OH)2 presents a robust and cost-effective pretreatment process for NRIWW.

Dual-chamber up-flow fluidized hollow-fiber anaerobic membrane bioreactor (UF-HF-AnMBR) treating synthetic purified terephthalic acid wastewater: Granular sludge regranulation and methane production

Up-flow anaerobic sludge blanket is a representative way to treat high-strength industrial wastewater, but suffers from granule collapse and poor long-term performance. In this study, a dual-chamber up-flow fluidized hollow-fiber anaerobic membrane bioreactor (UF-HF-AnMBR) was constructed to enhance sludge regranulation and process stability for purified terephthalic acid (PTA) wastewater treatment. A stable and satisfactory aromatic compound removal (>99 %) was achieved at the organic loading rate of 7.15 ± 0.21 g-COD·Lreactor−1·d−1, with the methane yield of 0.345 ± 0.028 L·g-CODremoved−1. Although the granular sludge collapsed initially induced the pore blocking and membrane fouling, membrane separation promoted the agglomeration of small particles, sludge regranulation and biomass retention. Parallel factor analysis identified that the amino acid tryptophan in extracellular polymeric substances exerted a more critical effect on membrane fouling. The 16S rRNA and network analysis revealed the robust proliferation/enrichment of Methanosaeta, Pelotomaculum, etc., as well as the establishment of mutualistic symbiotic relationship among different species, ensured a stable microbial community and created a favorable circumstance for highly effective anaerobic treatment of PTA wastewater. This study proves that UF-HF-AnMBR can be an efficient and promising technique for sludge regranulation and microbe enrichment, advancing its application in PTA wastewater treatment and bioenergy recovery.

Improving bioenergy recovery from municipal wastewater with a novel cloth-filter anaerobic membrane bioreactor

Anaerobic membrane bioreactors (AnMBR) have been used for treating high-strength industrial wastewater at full-scale and the potential to use them for mainstream municipal wastewater treatment presents an important opportunity to turn energy-intensive plants into net-energy producers. However, several limitations of the AnMBR technology have prevented their adoption in the municipal wastewater industry, namely, high membrane cleaning energy demand and low membrane flux. This study demonstrated a novel AnMBR configuration that uses a commercially available cloth filter technology to address the key limitations of cleaning energy and membrane flux. The cloth filter anaerobic membrane bioreactor (CFAnMBR) is comprised of an anaerobic fixed-film bioreactor coupled with a cloth filter membrane with nominal pore size of 5 µm. The pilot CFAnMBR was operated for 150 days through the winter at a municipal wastewater plant in central Illinois (minimum/average influent temperature 5/13°C). The CFAnMBR increased membrane flux by more than 2 orders of magnitude (3,649 ± 1,246 L per meter squared per hour) and reduced cleaning energy demand by 78%—92% (0.0085 kWh/m3) relative to previously reported AnMBR configurations. With the CFAnMBR, average chemical oxygen demand and total suspended solids removal were 66% and 91%, respectively, and were shown to be increased up to 88% and 96% by in-line coagulant dosing with ferric chloride. Average headspace methane yield was 154 mL CH4/g CODremoved by the end of the study period with influent temperatures of 11°C± 4°C. The CFAnMBR resolves major limitations of AnMBR technology by employing a commercially-available technology already used for other municipal wastewater treatment applications.

Application of Integrated Technologies for the Treatment of High-Strength Industrial Wastewater in Vietnam

Application of Integrated Technologies for the Treatment of High-Strength Industrial Wastewater in Vietnam

Automated Testing Apparatus for Ceramic Membrane Filtration of High-Strength Industrial Wastewater

Automated Testing Apparatus for Ceramic Membrane Filtration of High-Strength Industrial Wastewater

Carbon-neutral potential in treatment of N, N-dimethylformamide-containing industrial wastewater: Comparative investigation of energy conservation, carbon reduction and expenditure between UASB and Fenton process

The methanogenic degradation of N, N-dimethylformamide (DMF) is a sustainable and low-carbon technology for the treatment of high-strength industrial wastewater. Compared with the state-of-the-art chemical degradation method like Fenton, the UASB process exhibited its promising superiority in bio-energy recovery, economic profit gaining and carbon emission reduction. The lab-scale UASB obtained high DMF removal efficiency of over 98 % with methane recovered as bio-energy at a limited organic loading rate (OLR) of 4.2 COD kg/m3/d. Compared with the Fenton process, the UASB process is demonstrated more suitable to the carbon-neutral treatment of high-strength DMF-containing wastewater: The Fenton process is suitable to the relative low COD concentration below 1500 mg/L; The UASB was capable of covering all electricity consumption when COD > 3586 mg/L; The UASB also achieved zero CO2 emission when COD > 5720 mg/L; The UASB process obtains net profit when COD > 3616 mg/L. This study provided clear evidence of the promising potential and remarkable feasibility of bio-energy production in carbon-neutral treatment of DMF-containing wastewater.

Chemical and biological combined treatment for sugarcane vinasse: selection of parameters and performance studies

Sugarcane vinasse has been reported as a high strength industrial wastewater that could cause severe environmental pollution due to its complex and bio-refractory compounds. Thus, the combined coagulation and sequencing batch biofilm reactor (SBBR) system was employed for the sugarcane vinasse treatment. This study aims to determine the recommended conditions of various parameters under coagulation and SBBR and investigate the effectiveness of combined processes. First, the approach of the coagulation process could achieve the maximum COD reduction and decolorization efficiencies of 79.0 ± 3.4% and 94.1 ± 1.9%, respectively, under the recommended conditions. Next, SBBR as an integrated biofilm reactor showed excellent synergistic biodegradability, removing 86.6 ± 4.3% COD concentration and 94.6 ± 3.8% color concentration at 3.0g·COD/L of substrate loading concentration. The kinetic studies of SBBR revealed that the first-order kinetic model was the best fit for COD reduction efficiency. In contrast, the second-order kinetic model was the best fit for decolorization efficiency. The SBBR reaction was further investigated by ultraviolet-visible spectrophotometry (UV-Vis). In the combined processes, SBBR followed by the coagulation process (SBBR-CP) showed greater COD reduction and decolorization efficiencies (97.5 ± 0.3 and 99.4 ± 0.1%) when compared to the coagulation process followed by SBBR (CP-SBBR). This study demonstrated the removal performance and potential application of the combined sequential process to produce effluent that can be reused for bioethanol production and fertigation. This finding provides additional insight for developing effective vinasse treatment using combined chemical and biological processes.

Application of Metallic Iron and Ferrates in Water and Wastewater Treatment for Cr(VI) and Organic Contaminants Removal

Iron species can act as electron donors, electron acceptors or serve as a sorbent to co-precipitate contaminants. These properties, along with its relatively low cost as a material, make iron an ideal compound for environmental applications in the removal of pollutants from water and wastewater. This study assesses the use of metallic iron as a reductant for the removal of toxic Cr(VI) from aqueous solutions, as well as the use of hexavalent iron (ferrates) for the removal of organic compounds, turbidity and biological contaminants from water and wastewater. Laboratory-scale experiments show that the Cr(VI) removal efficiency of metallic iron filling materials, such as scrap iron fillings, via reduction to Cr(III) and the subsequent precipitation/filtration of aggregates can reach values over 99.0%. Moreover, the efficiency of ferrates, in situ synthesized via a low-cost Fe0/Fe0 electrochemical cell, in the removal of organic compounds, turbidity and biological contaminants from high-strength industrial wastewater, biologically treated wastewater and natural water can also reach values over 99.0%. The results showed that iron species can be applied in low-cost and environmentally friendly technologies for natural water remediation and wastewater treatment. Furthermore, the study showed that the challenge of an iron material’s surface passivation, as well as of ferrates’ procurement cost and stability, can be resolved via the application of ultrasounds and via in situ ferrate electrosynthesis.

Carbon-neutral treatment of N, N-dimethylformamide-containing industrial wastewater by anaerobic membrane bioreactor (AnMBR): Bio-energy recovery and CO2 emission reduction

High-strength industrial wastewater containing approximately 2000 mg/L of N, N-dimethylformamide (DMF) was treated by the anaerobic membrane bioreactor (AnMBR) during a long-term operation with the concept of carbon neutrality in this study. Bio-methane was recovered as bio-energy or bio-resource from DMF-containing wastewater along with the CO2 emission reduction. The results are clear evidence of the feasibility of carbon–neutral treatment of DMF-containing wastewater by the AnMBR. With an effective degradation under the organic loading rate of 6.53 COD kg/m3/d at the HRT of 12 h, the AnMBR completely covered the energy consumption during long-term operation by saving electricity of 4.16 kWh/m3 compared with the conventional activated sludge process. The CO2 emission of the AnMBR was just 1.06 kg/m3, remarkably reducing 1.45 kg/m3 of CO2. The treatment of DMF-containing wastewater by the AnMBR perfectly realized the goal of carbon neutrality, and was considered as an alternative to the conventional activated sludge process.

Performance intensification of constructed wetland technology: a sustainable solution for treatment of high-strength industrial wastewater.

The objectives of this study were to: (1) assess the intensification of chemical oxygen demand (COD) and phosphate (PO4-P) removal; and (2) generate a set of rate constants of COD degradation (kCOD) and phosphate (kPO4-P) removal for the treatment of industrial wastewater (WW) using intensified adsorption beds. Two horizontal subsurface flow constructed wetlands (HSSFCWs) filled with coal ash and alum sludge and two conventional HSSFCWs packed with gravels were operated with different loadings of COD and PO4-P at a hydraulic retention time (HRT) of 24 hrs at water depth of 0.40 m. The bed performance was analysed for COD and PO4-P removal efficiency. The intensified HSSFCWs outperformed the control beds by a mean COD and PO4-P removal efficiency of 43 and 49%, respectively. The progression of COD and PO4-P removal along the system was fitted into the first-order plug flow model (K-C model). In this study the kCOD values ranged from 0.36 to 0.65 m/d with a mean of 0.46 ± 0.08 m/d (n = 30). The kPO4-P values ranged from 0.74 to 1.76 m/d and averaged to 1.23 ± 0.37 m/d (n = 30), irrespective of the condition applied. Hence, these data can be used for future projects using HSSFCWs to treat industrial wastewater.

Industrial Wastewater Treatment Efficiency of Mixed Substrate (Pumice and Scoria) in Horizontal Subsurface Flow Constructed Wetland: Comparative Experimental Study Design

The discharge of untreated wastewater causes serious public and environmental health problems. Hence, the present study aimed to evaluate the combined adsorption potential of the two substrates (Pumice and Scoria) in a horizontal subsurface flow constructed wetland. The substrates were collected from the Ethiopian rift belt. Composite samples from tannery wastewater before and after treatment of four different retention times (RT) were collected and analyzed. Chrysopogon zizanioides was planted in one of the mixed substrate beds and grown for 5 months before running wastewater for the treatment. The maximum removal efficiency of the planted bed revealed that BOD5 at RT 7 days effluent concentration of 59.33 mg/L (96.38% removal), COD at RT 7 days 129.33 mg/L (98.14% removal), NO3-N at RT 7 days 0.28 mg/L (99.76% removal), TN 27.33 mg/L (95.80% removal), PO4-P RT 9 days 0.01 mg/L (99.9% removal), TP at RT 7 days 6 mg/L (95% removal), Sulfide at RT 7 days 0.27 mg/L (99.9% removal), sulfate at RT 9 days 87.9 mg/L (91.8% removal), and total Chromium at RT 7 days 0.1 mg/L (99.45% removal) respectively. The efficiency of the study and control beds was tested by a Two-Sample t-Test. The result showed that there was a significant difference at a 95% confidence interval, p-value = .002. Hence, the mixed substrate with plants performs better than the unplanted one, which means it can be effective for the treatment of high-strength industrial wastewater using horizontal subsurface flow constructed wetland.

Evaluation of membrane cake fouling mechanism to estimate design parameters of a submerged AnMBR treating high strength industrial wastewater

A mathematical model, which was previously developed for submerged aerobic membrane bioreactors, was successfully applied to elucidate the membrane cake-layer fouling mechanisms due to bound extracellular polymeric substances (eEPS) in a submerged anaerobic membrane bioreactor (SAnMBR). This biofouling dynamic model explains the mechanisms such as attachment, consolidation and detachment of eEPS produced in the bioreactor on the membrane surface. The 4th order Runge-Kutta method was used to solve the model equations, and the parameters were estimated from simulated and experimental results. The key design parameters representing the behaviour of cake fouling dynamics were systematically investigated. Organic loading rate (OLR) was considered a controlling factor governing the mixed liquor suspended solids (MLSS), eEPS production, filtration resistance (Rt), and transmembrane pressure (TMP) variations in a SAnMBR. eEPS showed a proportional relation with OLR at subsequent MLSS variations. The consolidation of EPS increased the specific eEPS resistance (αs), influencing the cake resistance (Rc). The propensities of eEPS showed a positive correlation with Rt and TMP. The outcomes of the study also estimated a set of valuable design parameters which would be vital for applying in AnMBRs treating industrial wastewater.

Removing high concentration of nickel (II) ions from synthetic wastewater by an indigenous microalgae consortium with a Revolving Algal Biofilm (RAB) system

This work is to evaluate the feasibility of using a revolving algal biofilm (RAB) reactor for nickel (Ni) removal from high strength industrial wastewater. The RAB reactor can grow an indigenous microalgal species consortium in a wastewater containing up to 5000 mg/L of Ni. The tolerance of RAB biomass to the high strength nickel was attributed to maintaining cells membrane integrity, which is possible due to its high amount of extracellular polymer substances (EPS). The RAB system also demonstrated a superior Ni removal performance with >90% Ni removal efficiency and 534 mg/L-day Ni removal rate. The advantage of RAB system in nickel removal over suspended-based system might be attributed to the high contents of EPS in RAB biofilm, given the fact that the extracellular nickel occupied 60% or higher of the total nickel in the RAB biofilm. The adsorption of Ni by the biomass harvested from the RAB reactors was also studied. The “biomass-physical-adsorption” was less effective than “growing-algae-while-removing-Ni” for Ni removal. Collectively, the results in this study demonstrated that the RAB reactor is a potential system for Ni removal from high strength industrial wastewater.

High Strength Wastewater Reclamation Capacity of Vetiver Grass in Tropics: The Case of Ethiopia.

It is generally accepted that industrial wastewater like tannery effluent is high strength wastewater. The aim of this study was to examine the capacity of Vetiver grass for the treatment of high strength wastewater in a constructed wetland. Two constructed wetland beds were designed and one of them was not planted used as a control group. The grass was planted with 20 cm by 20 cm distance from each seedling. The biometric characteristics of Vetiver grass was evaluated by taking randomly selected clusters of the grass. The concentration of chromium in the extract of parts of the grass was determined by atomic absorption spectrophotometer. The Chromium bioaccumulation and Translocation factor was estimated. Composite samples before and after treatment of 4 different hydraulic retention time was collected. The physiochemical analysis of the wastewater has been carried out. The constructed wetland bed with Vetiver grass performed that, BOD, COD, NH4-N, NO3-N, TN, PO4-P, and TP were reduced at the retention time of 9 days by 91.9%, 96.3%, 62%, 86%, 88.7%, 96.3%, and 92.2% respectively. Chromium was also reduced by 97% at retention time of both 7 and 9 days over the planted bed. The bed with plant performs significantly better than without plant at P-value <.01. Therefore, Vetiver grass has a capacity to reclaim high strength industrial wastewater in tropical areas.

An industrial insight on treatment strategies of the pharmaceutical industry effluent with varying qualitative characteristics

Abstract This study aims to provide non-biological treatment solutions to the pharmaceutical industry, depending on the quantitative and qualitative aspects of the wastewater. Commonly overlooked aspects of industrial wastewater such as its fluctuating characteristics, selection of suitable sampling points, and adopting an appropriate treatment methodology are addressed. Different units in a drug-producing industry and chief ingredients at each stage were identified. An appropriate sampling point was finalized following a series of systematic and repeated samplings of prominent industrial locations, at different periods. High organic and solids strength industrial wastewater samples were characterized and subjected to various physico-chemical and oxidative techniques, namely electrocoagulation (EC), chemical coagulation, photocatalytic oxidation, electro-Fenton’s (EF), Photo-Fenton’s (PF), and Fenton’s oxidation. The highest total organic carbon (TOC) reduction efficiencies about 47, 23, and 62 % were obtained from Fenton’s oxidation for distinct samplings. The variation in quality of effluent heavily influences the treatment efficacies of individual treatment schemes. Hence, rigid treatment protocols are inadvisable to propose for industrial perspectives to handle diurnal variations in effluent characteristics. Rather, industry-specific solutions may be provided, depending on the type of wastewater generated.

Application of Composite Pre-Polymerized Coagulants for the Treatment of High-Strength Industrial Wastewaters

The aim of this study was the investigation of alternative pre-polymerized coagulants for the treatment of high-strength industrial wastewaters, such as those created by tanneries, or by yeast production industries. The novel inorganic composite coagulant examined in this study (as well as variations of it) was denoted as PSiFAC1.5-10-15. The contribution of a typical polyelectrolyte to improve the effectiveness of the coagulation/flocculation (C/F) process was additionally studied, either by adding it separately (i.e., as a flocculant aid) or by co-polymerizing it within the structure of inorganic coagulant (denoted as PAPEFAC1.5-10-15). It was found that the PSiFAC1.5:10:15 coagulant, either with or without the addition of polyelectrolyte, can provide better efficiency for the C/F process than the conventional coagulants. For example, the addition of 80 mg Al/L in yeast production wastewater samples resulted in a 56% reduction of COD, 40% of turbidity, and 43% of phosphates, regarding the pre-treated anaerobically wastewater samples and reduced by an extra 22%, 14%, and 38% for the pre-treated anaerobically plus aerobically wastewater samples, respectively. The residual aluminum concentration in the treated wastewaters was found to be below the legislation limit of 200 μg Al/L. The characterization of coagulants showed the relatively higher Al13 content of 51% and 43% for the cases of PSiFAC1.5-10-15 and PAPEFAC1.5-10-15, respectively, accompanied by the high zeta-potential measurements (50.5 and 39.5 mV).

A Study of Refractory Industrial Wasteawater Treatment by Fe/C Microelectrolysis Combining with Multiphase Fluid Catalytic Oxidation

Refractory industrial wastewater used to be high strength in diversified organic pollution and biotoxicity. It is becoming a formidable global environmental issue. This study revealed a novel process of Fe/C microelectrolysis combining with multiphase fluid catalytic oxidation to treat high strength industrial wastewater (take pharmaceutical wastewater as an example). Different catalysts were investigated to optimize the operation parameters. The results showed that the average COD removal rate of single microelectrolysis in pharmaceutical wastewater was 23.1%. After microelectrolysis treatment, the B/C was improved from 0.11 to 0.23. The PVA pellets were set as the fluidized catalysts with activated carbon (AC), TiO2 and MnO2, respectively. The AC, TiO2 and MnO2 could significantly promote the COD degradation of pharmaceutical wastewater. When combining with multiphase fluid catalytic oxidation, the PVA/MnO2 indicated a higher COD removal efficiency of 51.6% with 0.4%H2O2 addition, the effluent B/C was 0.34.

Electrochemically assisted sulfate reduction autotrophic denitrification nitrification integrated (e-SANI®) process for high-strength ammonium industrial wastewater treatment

Large amount of high-strength ammonium industrial wastewater was discharged in China causing serious environmental pollution. In this work, an electrochemically assisted sulfate reduction autotrophic denitrification and nitrification integrated (e-SANI) process was developed by coupling a microbial electrolysis cell (MEC) with a conventional SANI process for high-strength ammonium wastewater treatment. In the e-SANI process, the MEC cathode was used for hydrogen-oxidizing autotrophic denitrification and simultaneously for pH elevation, while the MEC anode oxidized residual sulfide in effluent for elemental sulfur recovery. As a key operational parameter, the cathode potential was controlled at −0.8, −0.9 and −1.0 V (vs. Ag/AgCl, saturated KCl) to evaluate the total nitrogen removal efficiency in the e-SANI process. The results indicated the maximum total nitrogen removal efficiency was significantly improved in the e-SANI system (56.9 ± 1.4% at −1.0 V) compared to the conventional SANI system (34.8 ± 2.3%). With the assistance of the anode, residual sulfide in effluent can be significantly eliminated through oxidation to elemental sulfur. Furthermore, microbial community in the e-SANI system was analyzed and Bacteroides and Thiobacillus were identified as the predominant denitrification bacteria in the cathode chamber. Conclusively, the developed e-SANI system extends the application of the SANI process and can be a promising technology for high-strength ammonium wastewater treatment.

Anaerobic Treatment of High Fat Content Wastewater in Microbial Electrochemical Cells

Microbial electrochemical cells (MECs) are devices in which anaerobic treatment of wastewater can occur in the anode chamber, where anode-respiring bacteria oxidize fatty acids produced from fermentation of waste organics to produce an electrical current. MECs are best suited for high-strength industrial wastewater streams, rather than dilute domestic wastewater streams. We have evaluated the possibility of using MECs for treatment of rendering wastewater, which contains high concentrations of fats (and often also proteins). We first conducted biochemical methane potential (BMP) tests to determine the anaerobic biodegradability of rendering wastewater (COD concentrations of ~7000 mg/L), and to determine optimum organic loading rate (relative to biomass concentration). Using the optimum conditions, we then conducted batch MEC studies to determine maximum current densities that could be produced, as well as the COD removal and conversion efficiencies. Maximum current densities of up to 2.5 A/m2 were produced, while COD conversion to electrical current ranged between 70-80%. Our studies indicate that MECs could become suitable for treatment of high fat content wastewater streams.