Treatment Of High-strength Industrial Wastewater Research Articles

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

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.

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.

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).

Robustness of anammox granular sludge treating low-strength sewage under various shock loadings: Microbial mechanism and little N2O emission

With the increasing application of anammox for the treatment of high-strength industrial wastewater, application of anammox in municipal sewage has been gaining more attention. Sludge granulation in particular enhances the enrichment and retention of anammox bacteria in municipal sewage treatment systems. However, the performance of granular sludge under continuous and varying hydraulic loading shock remains little understood. In this study, the robustness of anammox granular sludge in treating low-strength municipal sewage under various shock loadings was investigated. Results showed that an upflow anaerobic sludge blanket (UASB) reactor with anammox granules performed well, with anammox specific activity up to 0.28 kg N/kg VSS/day and anti-loading shock capability up to 187.2 L/day during the 8-month testing period. The accumulation rate of N2O (<0.01 kg N/kg VSS/day) in the liquid phase was seven times higher than that of the gas phase, which could be mainly attributed to the incomplete denitrification and insufficient carbon source. However, only a small part of the produced N2O escaped into the atmosphere. High-throughput sequencing and molecular ecological network analyses also identified the bacterial diversity and community structure, indicating the potential resistance against loading shock. The composition and structural analyses showed that polysaccharides were an important functional component in the tightly bound extracellular polymeric substances (TB-EPS), which was the major EPS layer of anammox granules. Scanning electron microscopy (SEM) also showed that the gaps in between the anammox-clusters in the granules inhibit the flotation of the sludge and ensure efficient settling and retention of anammox granules.

Aerobic granulation technology: Laboratory studies to full scale practices

Abstract Aerobic Granulation Technology for treatment of wastewater is developed in last two decades. Aerobic Granules are special type of self-immobilization of microorganisms, without any surface medium for growth of microbial film. They have compact cores and have high diffusional confrontations to external particles and, hence have high acceptance of the toxic compounds to their integral cells. Most aerobic granules are large and have a compact core, and so are recommended for use in the biological treatment of high-strength industrial wastewaters. This technology requires small foot print, 25% of the area of conventional activated sludge setup and this process can reduce up to 50% on energy-costs. This paper reviews on start-ups, advances in aerobic granulation technology from laboratory studies to pilot scale and to its full-scale application for treatment of different types of domestic and industrial wastewater. Gaps in knowledge and new ideas for future work of aerobic granulation technology are also being discussed.

Advanced treatment of sodium dithionite wastewater using the combination of coagulation, catalytic ozonation, and SBR

ABSTRACTA combined process of coagulation–catalytic ozonation–anaerobic sequencing batch reactor (ASBR)–SBR was developed at lab scale for treating a real sodium dithionite wastewater with an initial chemical oxygen demand (COD) of 21,760–22,450 mg/L. Catalytic ozonation with the prepared cerium oxide (CeO2)/granular activated carbon catalyst significantly enhances wastewater biodegradability and reduces wastewater microtoxicity. The results show that, under the optimum conditions, the removal efficiencies of COD and suspended solids are averagely 99.3% and 95.6%, respectively, and the quality of final effluent can meet the national discharge standard of China. The coagulation and ASBR processes remove a considerable proportion of organic matter, while the SBR plays an important role in post-polish of final effluent. The ecotoxicity of the wastewater is greatly reduced after undergoing the hybrid treatment. This work demonstrates that the hybrid system has the potential to be applied for the advanced treatment of high-strength industrial wastewater.

The close relation between Lactococcus and Methanosaeta is a keystone for stable methane production from molasses wastewater in a UASB reactor.

The up-flow anaerobic sludge blanket (UASB) reactor is a promising method for the treatment of high-strength industrial wastewaters due to advantage of its high treatment capacity and settleable suspended biomass retention. Molasses wastewater as a sugar-rich waste is one of the most valuable raw material for bioenergy production due to its high organic strength and bioavailability. Interpretation for complex interactions of microbial community structures and operational parameters can help to establish stable biogas production. RNA-based approach for biogas production systems is recommended for analysis of functionally active community members which are significantly underestimated. In this study, methane production and active microbial community were characterized in an UASB reactor using molasses wastewater as feedstock. The UASB reactor achieved a stable process performance at an organic loading rate of 1.7~13.8-g chemical oxygen demand (COD,·L(-1) day(-1); 87-95 % COD removal efficiencies), and the maximum methane production rate was 4.01 L-CH4·at 13.8 g-COD L(-1) day(-1). Lactococcus and Methanosaeta were comprised up to 84 and 80 % of the active bacterial and archaeal communities, respectively. Network analysis of reactor performance and microbial community revealed that Lactococcus and Methanosaeta were network hub nodes and positively correlated each other. In addition, they were positively correlated with methane production and organic loading rate, and they shared the other microbial hub nodes as neighbors. The results indicate that the close association between Lactococcus and Methanosaeta is responsible for the stable production of methane in the UASB reactor using molasses wastewater.

Assessment of fouling-resistant membranes for additive-free treatment of high-strength wastewaters

In this contribution, we investigate the use of fouling-resistant and cleanable membranes designed for treatment of oily water in the treatment of high-strength industrial wastewaters that present challenges to classical treatment technologies. Membrane surfaces were characterized by spectroscopy and electron microscopy pre- and post-filtration to determine the extent of fouling. Low molecular weight cutoff membranes showed stable permeate fluxes without the need for intermittent cleaning, characteristic of systems with low degrees of internal fouling. For 100kDa molecular weight cutoff membranes, flux decline was more severe. While polymer-modified membranes processed ~26% more permeate than the unmodified membranes in this case, flux recovery after a membrane cleaning step was low and similar for the unmodified and modified membranes, characteristic of high degrees of internal fouling. All membranes reduced turbidity nearly 100% and chemical oxygen demand was reduced 70–84%. These results indicate that ‘tight’ ultrafiltration membranes designed for treatment of oily waters can be used for primary treatment of other highly impaired wastewaters, and the use of more ‘open’ ultrafiltration membranes will require further development and optimization of cleaning protocols.

Developments and future potentials of anaerobic membrane bioreactors (AnMBRs)

The coupling of anaerobic biological process and membrane separation could provide excellent suspended solids removal and better biomass retention for wastewater treatment. This coupling improves the biological treatment process while allowing for the recovery of energy through biogas. This review gives a basic description of the anaerobic wastewater treatment process, summarizes the state of the art of anaerobic membrane bioreactors (AnMBRs), and describes the current research trends and needs for the development of AnMBRs. The research interest on AnMBR has grown over the conventional anaerobic processes such as upflow anaerobic sludge blanket (UASB). Studies on AnMBRs have developed different reactor configurations to enhance performances. The AnMBR performances have achieved comparable status to other high rate anaerobic reactors. AnMBR is highly suitable for application with thermophilic anaerobic process to enhance performances. Studies indicate that the applications of AnMBR are not only limited to the high strength industrial wastewater treatment, but also for the municipal wastewater treatment. In recent years, there is a significant progress in the membrane fouling studies, which is a major concern in AnMBR application.

Dominance of yeast in activated sludge under acidic pH and high organic loading

Flow cytometry-fluorescent in situ hybridization (FC-FISH) was used to investigate the effect of controlled pH and/or varied organic loading on the content of yeast and bacterial cells in an activated sludge system (AS) individually operating in continuous and batch mode for treatment of high-strength industrial wastewater. Specifically, we attempted to develop a yeast-predominant activated sludge system (Y-AS). For the batch-mode AS, bacteria-dominated AS (B-AS) obtained at pH 6.5–7.5 induced higher chemical oxygen demand (COD) removal than Y-AS obtained at acidic pH (5.0–6.0 and 4.0–5.0). For the continuous-mode AS operating at COD loadings of 2.5–2.8 kg COD m −3 d −1, it was difficult to achieve a Y-AS solely by controlling the pH level at 7.0 to 5.1 then to 4.1 because bacteria stably accounted for greater than 98% of the total cells, regardless of the pH levels. Therefore, the effects of varied COD loadings (2.1, 8.7 and 21.0 kg COD m −3 d −1) on continuous-mode AS operation at acidic pH (4.5) was investigated. Both acidic pH and high COD loading levels were found to be prerequisites for yeast to dominate the sludge microbial community in the continuous-mode AS.

Survey of MBR market: Trends and perspectives in China

Membrane bioreactor (MBR) has gained considerable attention for wastewater treatment and reuse in China in the last two decades. Comparing with the global MBR market, which has an average annual growth rate of 10.9%, the average annual growth rate in China is nearly 100% in recent years. In the past 10 years, publications on MBR researches and applications for wastewater treatment have increased sharply. Over three hundred MBR plants have been successfully applied into practice for different wastewater treatments, such as municipal wastewater, bathing wastewater, restaurant wastewater, landfill leachate, hospital wastewater, petrochemical wastewater and high-concentration industrial wastewater. These plants have capacities ranging from 10 to 100,000 m 3/d, among which over 12 MBR plants have capacities exceeding 10,000 m 3/d. The largest MBR plant, i.e. Beijing Kunyu River WWPT, which has a capacity of 100,000 m 3/d for municipal wastewater treatment and reuse, was constructed in Beijing by Origin Water Technology Co., Ltd. The largest MBR plant for industrial wastewater treatment was located in Tianjin and installed by Motimo Membrane Inc., which has a capacity of 30,000 m 3/d. The largest MBR application for industrial sectors was petrochemical wastewater treatment, and over ten MBR plants each exceed a capacity of 5000 m 3/d. In South-east China, the constructed MBRs are mostly involved in the high-strength industrial wastewater treatment while in North China MBRs mainly focused on municipal wastewater treatment and reuse. For an MBR commercial application in China, MBR plants were constructed by a lot of home-grown companies such as Tianjin Motimo Membrane Technology Co., Ltd., Beijing Origin Water Technology Co., Ltd. and Omexell Environmental Engineering Co., Ltd. and overseas-funded companies like Zenon-GE and CNC-Simens. Origin Water occupies the majority of the MBR market in China, whereas CNC-Simens and Zenon-GE have a larger number of installations in other parts of China. MBR unit key suppliers in China are Zenon (Canada), Mitsubishi-Rayon (Japan), Toray (Japan), Kubota (Japan), Norit (Netherlands), Motimo (China) etc. Due to more stringent regulations and wastewater reuse strategies, it is expected that a significant increase in MBR plant capacity and a widening of application areas will occur in the future.

Effect of 200 days' sludge retention time on performance of a pilot scale submerged membrane bioreactor for high strength industrial wastewater treatment

A high strength industrial wastewater was treated using a pilot scale submerged membrane bioreactor (MBR) at a sludge retention time (SRT) of 200 d. The MBR was operated at a high sludge concentration of 20 g/L and a low F/M ratio of 0.11 during 300 d of operation. It was found that the MBR could achieve COD and TOC overall removal efficiencies at more than 99 and 98% TN removal. The turbidity of the permeate was consistently in the range of 0.123 to 0.136 NTU and colour254 absorbance readings varied from 0.0912 to 0.0962 a.u. cm(-1). The sludge concentration was inversely proportional to the hydraulic retention time (HRT), yielded excellent organic removal and extremely low sludge production (0.0016 kgVSS/day).

Toxicity assays to determine the start-up strategy for an anaerobic sequencing batch reactor (anSBR)

Addition of glucose as the co-substrate and the use of a water-based polymer to enhance granulation were studied with the aim of shortening the start-up period of an anSBR (anerobic sequencing batch reactor) for high-strength industrial wastewater treatment. An initial start-up feed composition consisting of 70% sucrose and 30% industrial wastewater was favorable to reduce the start-up time. Increase in the average particle size and reduction in settled supernatant turbidity was observed with increased water-based polymer addition up to a concentration of 0.1 m/L. Polymer dosages above 0.1 ml/L were undesirable as big and "flaky" flocs were formed which prevented the flocs from settling quickly. Addition of 0.005 ml/L to 0.1 ml/L polymer to the mixed liquor had no observable adverse effects on the anaerobic biomass metabolism. Instead, the addition of the polymer appeared to improve biogas production and had an overall positive effect on anSBR performance treating the industrial wastewater.

Laboratory studies on the temperature-phased ASBR system

Treatment of high-strength industrial wastewater with the temperature-phased anaerobic sequencing batch reactor (ASBR) system has shown positive results in laboratory scale studies. The system achieved COD removals as high as 95% and 90% for soluble and total COD, respectively, up to COD loadings of 22 g COD/L/day. Non-fat dry milk was used as a synthetic substrate. The system consisted of two reactors operated in series at different temperatures. Phase I of the system was operated at 55°C and the Phase II was operated at 35°C. The total hydraulic retention time in the system was 18 hours (6 hours in the Phase I and 12 hours in the Phase II). The temperature-phased system incorporates advantages of both thermophilic treatment (high reaction rates) and mesophilic treatment (higher quality effluent) while minimizing the disadvantages such as odors commonly associated with thermophilic treatment and lower treatment rates of mesophilic treatment. This study was conducted using ASBRs. The ASBR was developed at Iowa State University by R.R. Dague. This process allows biomass to increase in the reactors and provides an environment for granulation to occur. Although the ASBR was used for these studies, the temperature-phased process is applicable to other anaerobic treatment processes as well.

Treatment of high-strength industrial wastewater by wet air oxidation—A case study

Treatment of high concentration chemical wastewater obtained from a petrochemical company by wet air oxidation (WAO) is studied. Experiments were conducted to investigate the effects of the mixer speed, operating pressure, initial pH of wastewater and temperature on the pollutant (chemical oxygen demand or COD) removal. Both air and oxygen were tested to determine their respective effect on the COD removal. Results showed that over 50% of COD removal can be easily realized in an hour of WAO treatment. Also considered in the present study was the catalytic WAO treatment of the high concentration wastewater. Copper sulfate (CuSO 4), cobalt oxide (Co 2O 3) and zinc oxide (ZnO) were employed as the catalysts. The COD removal efficiency of the catalytic WAO process was found to vary significantly with the catalyst utilized with CuSO 4 being the most effective.

Laboratory studies on the temperature-phased ASBR system

Abstract Treatment of high-strength industrial wastewater with the temperature-phased anaerobic sequencing batch reactor (ASBR) system has shown positive results in laboratory scale studies. The system achieved COD removals as high as 95% and 90% for soluble and total COD, respectively, up to COD loadings of 22 g COD/L/day. Non-fat dry milk was used as a synthetic substrate. The system consisted of two reactors operated in series at different temperatures. Phase I of the system was operated at 35°C and the Phase II was operated at 35°C. The total hydraulic retention time in the system was 18 hours (6 hours in the Phase I and 12 hours in the Phase II). The temperature-phased system incorporates advantages of both thermophilic treatment (high reaction rates) and mesophilic treatment (higher quality effluent) while minimizing the disadvantages such as odors commonly associated with thermophilic treatment and lower treatment rates of mesophilic treatment. This study was conducted using ASBRs. The ASBR was developed at Iowa State University by R.R. Dague. This process allows biomass to increase in the reactors and provides an environment for granulation to occur. Although the ASBR was used for these studies, the temperature-phased process is applicable to other anaerobic treatment processes as well.