Hydrolysis Acidification Research Articles

Degradation of Carcinogenic Hydroquinone in Coal Gasification Wastewater by Using Anaerobic Shaker Test

Coal gasification wastewater, as a typical industrial wastewater has poor biodegradability and high toxicity. In this paper, simple anaerobic shaker test was conducted to investigate the degradation of hydroquinone in coal gasification wastewater. Anaerobic sludge shaker test were run for 27, 50 and 73 days, the phenol concentration were adjusted to 300 mg/L and 500 mg/L with pH 7.5, respectively. The experimental results also showed that this system could effectively deal with COD and phenol removal and remain in a stable level when the operational parameters altered while the hydrolysis acidification at 45h is appropriate. Organics degradation and transformation of anaerobic coal gasification wastewater samples at 12h, 24h, 36h, 48h, and 60h were analyzed by GC/MS and it was found that hydrolysis acidification played an important role in degradation of methyl phenol, hydroquinone and refractory compounds. Therefore, the results illustrated that the simple anaerobic shaker process is an easy way for pollutant degradation and treat coal gasification wastewater effectively.

Variation of Total Volatile Fatty Acids (VFAs) and its Components in Hydrolytic Acidification Treatment of Dyeing Wastewater

As an important judgement index, Volatile Fatty Acids (VFAs) is the indispensable research object in hydrolytic acidification treatment process. The article studied the total VFAs and its components from the start to stable period of an hydrolytic acidification reactor treating simulated dyeing wastewater by a distilled method and ion chromatography system (ICS-90), respectively. The results revealed that it experienced about 90 days for the hydrolytic acidification reactor to be stable. The COD removal ratio hovered around 45% without large fluctuation, and the ADMI removal ratio ranged from about 50% to 81%. The total VFAs increased from the initial 24.72 mg/L to about 150 mg/L. The component analysis revealed that acetic acid increased to the main component and the proportion of propionic acid decreased, which reflected a good hydrolytic acidification effect after 100 days treatment of simulated dyeing wastewater.

Treatment of Heavy Oil Wastewater by HCR with Hydrolytic Acidification Process

To reduce the pollutants of a heavy oil wastewater, a process of high performance compact reactor (HCR) coupled with hydrolytic acidification was investigated, focusing on the removal effect of the typical pollutants and the hydrolytic retention time (HRT) of HCR system.. The results showed the removal rates of COD and oil were 20.4%~40.7% and 25.5%~39.8% after the treatment of hydrolytic acidification, while the whole system reached the 80% removal rate. When the HRT was 48h and jet flow was 3.1m3/h in HCR process, COD and oil were blow 200 mg/L and 10 mg/L, which met the requests of next treatment of wastewater.

Study on Treatment of College Wastewater Based on Hydrolysis Acidification Bio-Contact Oxidation Process

This study analyzed the characteristics and the main composition of college wastewater and designed the test method of wastewater treatment accordingly. The application of hydrolysis acidification - biological contact oxidation process can improve the treatment effect of college wastewater. This study also carried out the correlation analysis of the treatment results and investigated the main influence factors, which can be controlled to get better treatment effect.

Combined hydrolysis acidification and bio-contact oxidation system with air-lift tubes and activated carbon bioreactor for oilfield wastewater treatment

This paper investigated the enhancement of the COD reduction of an oilfield wastewater treatment process by installing air-lift tubes and adding an activated carbon bioreactor (ACB) to form a combined hydrolysis acidification and bio-contact oxidation system with air-lift tubes (HA/air-lift BCO) and an ACB. Three heat-resistant bacterial strains were cultivated and subsequently applied in above pilot plant test. Installing air-lift tubes in aerobic tanks reduced the necessary air to water ratio from 20 to 5. Continuous operation of the HA/air-lift BCO system for 2months with a hydraulic retention time of 36h, a volumetric load of 0.14kgCOD/(m3d) (hydrolysis-acidification or anaerobic tank), and 0.06kgCOD/(m3d) (aerobic tanks) achieved an average reduction of COD by 60%, oil and grease by 62%, total suspended solids by 75%, and sulfides by 77%. With a COD load of 0.56kg/(m3d), the average COD in the ACB effluent was 58mg/L.

Refining wastewater treatment using EGSB-BAF system

The performance of an expanded granular sludge bed (EGSB) in combination with a biological aerated filter (BAF) system for petroleum refining wastewater treatment was investigated. The system was monitored for two months at a hydraulic retention time of 17.5 h and a digestion temperature of 34 ± 1°C. The results showed that the total chemical oxygen demand (CODCr) and oil removal efficiencies were up to 90 and 87%, respectively, with the average CODCr and oil concentrations of 85 and 11 mg/L in the system effluent. Moreover, almost 97% of suspended solids (SS) were removed by the system and the effluent SS concentration was only 15 mg/L. The sludge yield coefficient of 0.0036 mg/mgCODCr showed a low excessive sludge production for the EGSB reactor. The excellent treatment performance indicated that this EGSB-BAF system could be appropriate for refining wastewater treatment. Besides, methane yield was only about 0.21 mLCH4/mgCODCr in the EGSB reactor, lower than the theoretical yields. The poor methane production together with the low oil concentration and increased biodegradability of effluent indicated that the biochemical reaction of refining wastewater mainly remains in hydrolytic acidification phase in the EGSB reactor. For this reason, it was proposed that a highly efficient anaerobic process such as EGSB could be used as a pre-treatment process to improve the biodegradation performance of the following aerobic biochemical treatment.

Biological pretreatment of tannery wastewater using a full-scale hydrolysis acidification system

To evaluate the performance of hydrolysis acidification (HA) system on the tannery wastewater treatment in a cold region, the effects of COD, SS, sulphides concentration and the low temperature on tannery wastewater treatment were investigated in a 5000 m3/d full-scale HA reactor. The results showed that the removal ratios of COD and SS were in the range of 20%–45% and 65%–82%, respectively. The average BOD/COD of the tannery wastewater was improved from 0.38 to 0.56, and the pH decreased from 8.4 to 7.6 after the HA treatment. The concentration of sludge and COD in the bottom of the HA reactor was significantly higher than those of the top region. The thickness sludge layer shortened the required hydraulic retention time and improved the SS removal efficiency. When the temperature of HA reactor dropped below 8 °C, the COD removal ratio decreased to less than 10%. However, the SS removal ratio was not obviously impacted. The results obtained from this study indicated that the HA system provided an effective biological pre-treatment of the tannery wastewater for organic loading reduction and biodegradability improvement, even in a cold season.

Stability of Fe–C micro-electrolysis and biological process in treating ultra-high concentration organic wastewater

Abstract Three kinds of industrial wastewater were treated using combined Fe–C micro-electrolysis (FCME), hydrolysis acidification (HA), and bio-contact oxidation (BCO) processes. Two waste streams were characterized as ultra-high concentration of organic wastewater (UHCOW, more than 150,000 mg/L of CODcr). The other stream called clean water (CW), was a mixture of lower-concentration industrial wastewater and office block sewage. Efficiency and stability of the combined system were investigated in a pilot-scale experiment. The combined system can be operated normally under most suitable conditions, but its operation stability is poor. With increasing the ratio of UHCOW/CW, activated carbon in the FCME tank and carriers in the HA tank are fouled by oil droplets and lose certain functions gradually after 10 days of operation. As a result, CODcr removal efficiency decreased, particularly in the FCME tank. Moreover, the highly concentrated contaminants will severely restrict the growth of the microorganism in BCO tanks. The method of adding CW primarily functions in determining the system’s stability. At UHCOW/CW ratio of 1:10, the system showed higher stability after changing the manner of adding CW. Interestingly, the CODcr of the wastewater can still be reduced from more than 150,000 mg/L to ∼500 mg/L upon increasing the quantity or quality of the UHCOW by 30% in the shock test.

Co-fermentation of oil palm lignocellulosic residue with pig manure in anaerobic leach bed reactor for fatty acid production

Batch experiments were performed to investigate the co-fermentation of palm oil empty fruit bunch (EFB) and pig manure (PM) at various PM mixing ratios (%PM) and flushing intervals (FI) over 60-day fermentation time (FT) using anaerobic leach bed reactors. Addition of PM promoted hydrolysis yield (ηh) and acidification yield (ηa) due to the more degradable and soluble nature of PM that gave out organic acids, and nutrients it supplemented. The highest ηh and ηa found were 27.9±0.3% and 51.7±2.6%, respectively. Longer FI that delayed bed flushing prolonged the dry condition where hydrolytic reaction could be enhanced. The developed multiple regression model with R2=0.87 and p<0.0001 suggested a good fit to the data and able to describe the interactive relationship of the parameters on total volatile fatty acids (VFA) production. The longer chain acids, i.e. propionic (C3), butyric (C4), and valeric (C5) acids, were found in higher concentrations with longer FI and higher pig manure mixing ratios. The mixing of an easier biodegradable pig manure as co-substrate could help induce higher degree of fermentation of the recalcitrant EFB.

Treatment of real high-concentration dyeing wastewater using a coagulation-hydrolysis acidification-multilevel contact oxidation system

An integrated system comprising coagulation, hydrolysis acidification, and multilevel contact oxidation was evaluated to make the dyeing effluent meet discharge standards. A new spiral biological carrier was first used in the treatment of dyeing wastewater. The chemical oxygen demand (COD), color, and biodegradability index (i.e., biological oxygen demand (BOD)/COD) of raw dyeing wastewater were 5051 mg/L, 404 times, and 0.29, respectively. During coagulation, 80% COD and 64% color were reduced with 80 mg/L polyaluminum chloride as coagulant. The hydraulic retention time (HRT) of subsequent hydrolysis acidification and multilevel contact oxidation was determined as 23.6 h. After the integrated treatment of coagulation–hydrolysis acidification–multilevel contact oxidation, COD, BOD, color, and ammonia removal efficiencies reached 98%, 99%, 92%, and 99%, respectively. The effluent met Class 1 discharge standards (GB4287-2012). In particular, the new spiral biological carriers used in multilevel contact oxidation led to significant total nitrogen (TN) removal. When the HRT of multilevel contact oxidation process was 16.4 h, the TN removal efficiency was 73.3%. The spiral carriers can provide an anoxic microenvironment in the inner part because of their high strength spiral structure, which facilitates the transformation from nitrate to nitrogen gas through simultaneous nitrification and denitrification. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 339–345, 2015

A Study on the Wastewater Treatment from Antibiotic Production

Wastewater from cephalosporin antibiotic production with high bio-toxicity is hard to degrade, and could cause great harm to environment and human being. In the present paper, wastewater from cephalosporin production was processed with biochemical treatments as hydrolytic acidification, Up-flow Anaerobic Sludge Bed(UASB), Sequencing Batch Reactor Activated Sludge Process(SBR), biological activated carbon process(BAC). Among them, hydrolytic acidification could efficaciously enhance the biodegradability of wastewater, and greatly increase effects of the subsequent anaerobic-aerobic treatment. The final BAC process could effectively eliminate chemical oxygen demand (COD) and chroma of wastewater treated by aerobic treatment, where COD attained below 100mg/L and chroma was 40. Therefore, wastewater after the previous treatments basically conformed to the discharge standard of “ Integrated wastewater discharge standard “(GB8978-1996).

Remediation of Oilfield Wastewater Produced From Alkaline/Surfactant/Polymer Flooding by Using a Combination of Coagulation and Bioaugmentation

In this study, performance of a full-scale combined treatment plant for oilfield wastewater from alkaline/surfactant/polymer flooding was investigated. The combined process consisted of chemical coagulation, hydrolysis/acidification, and bio-contact oxidation. The experimental results demonstrated that chemical coagulation treatment with polymeric ferric sulfate proved to be the most effective in removing the chemical oxygen demand (>80%) from the wastewater under the dosage of 600 mg/m3. The highest acidification efficiency in hydrolysis acidification tank was 25.8% at hydraulic retention time of 20 h. The average values of chemical oxygen demand, biochemical oxygen demand, oil, and NH3-N of the combined process could be reduced to 116, 19, 4, 11, and 20 mg/L, respectively. The final effluent could meet the class II national wastewater discharge standard of petrochemical industry of China.

Integrated Processing Effects on Ink Wastewater of 500t/Day

By adopting chemical coagulation + efficient sedimentation tank + hydrolysis acidification composite reactor + biological contact oxidation tank + Biological Aerated Filter + adsorption filter integrated processing design, the wastewater from ink production and printing ink application has been treated here. The testing results shown that the effects of the integration treatment process on Ink Wastewater of 500 tons per day are reasonable. The cost of the process is not more than 1.8 Yuan/t, and it can be a better integrated process.

Enhanced anaerobic digestion of waste activated sludge digestion by the addition of zero valent iron

Anaerobic digestion is promising technology to recover energy from waste activated sludge. However, the sludge digestion is limited by its low efficiency of hydrolysis–acidification. Zero valent iron (ZVI) as a reducing material is expected to enhance anaerobic process including the hydrolysis–acidification process. Considering that, ZVI was added into an anaerobic sludge digestion system to accelerate the sludge digestion in this study. The results indicated that ZVI effectively enhanced the decomposition of protein and cellulose, the two main components of the sludge. Compared to the control test without ZVI, the degradation of protein increased 21.9% and the volatile fatty acids production increased 37.3% with adding ZVI. More acetate and less propionate are found during the hydrolysis–acidification with ZVI. The activities of several key enzymes in the hydrolysis and acidification increased 0.6–1 time. ZVI made the methane production raise 43.5% and sludge reduction ratio increase 12.2 percent points. Fluorescence in situ hybridization analysis showed that the abundances of hydrogen-consuming microorganisms including homoacetogens and hydrogenotrophic methanogens with ZVI were higher than the control, which reduced the H2 accumulation to create a beneficial condition for the sludge digestion in thermodynamics.

Treatment Phenolic Compounds in Coal Gasification Wastewater by Hydrolytic Acidification-AO Process

Using hydrolytic acidification-AO process treating coal gasification wastewater, the COD, total phenols in the effluent and the removal efficiencies were studied. The start-up period was separated to two stages with influent COD concentration of 1500 and 2500mg/L. After 59 days operation, the COD and total phenols removal efficiencies were 80.3% and 72.9%, respectively. The COD and total phenols increased to 925.4 and 238.7mg/L when the HRT was reduced to 6h with the corresponding concentrations of influent were 2512.9 and 493.4mg/L. When the HRT in hydrolytic acidification was reduced to 100%, the removal of total phenols dropped from 75.4% to 57.6%. The bigger circle ratio of 500% didn't have obviously effect on total phenols removal of the process.

Research of Biological Phase in Contact Oxidation Pond for Jeans Washing Wastewater Biochemical Treatment

The combined process of coagulation, hydrolytic acidification and contact oxidation was applied to treat the jeans washing wastewater, and the microorganism and COD concentration in the contact oxidation pond was monitored 40 consecutive days. the results showed that Vorticella, rotifers, arcellas, chironomid larvae, nematodes of the genus, changed in the number of the wastewater treatment had obvious indicating effect, activated sludge on the chromaticity of grain had obvious effect of adsorption, and flocculation particle morphological changes could also play a role in indicating.

Molecular Weight Distribution of DOC in Effluent of Petrochemical Wastewater Treatment Units

The results showed that DOC, UV254 and SUVA all presented a characteristic that organics was mainly concentrated on molecular weight &lt;1kDa.Except organics with molecular weight &lt;1kDa, the molecular weight of organics in Influent and effluent of Hydrolytic Acidification respectively distributed in the range of &lt;1kDa, 30~100kDa and 1~3kDa, 10~30kDa. Organics in effluent of Anaerobic, Aerobic, Secondary sedimentation tank and Contact oxidation occupied proportions in all ranges of molecular weight distribution but relatively lower.

Combined Mesophilic Anaerobic and Thermophilic Aerobic Digestion Process: Effect on Sludge Degradation and Variation of Sludge Property

One-stage autothermal thermophilic aerobic digestion (ATAD) is effective for the reduction of volatile solids (VSs) and pathogen in sewage sludges. A novel process of combining mesophilic (<35 °C) anaerobic digestion with a thermophilic (55 °C) aerobic digestion process (AN/TAD) occurred in a one-stage digester, which was designed for aeration energy savings. The efficiency of sludge degradation and variation of sludge properties by batch experiments were evaluated for the AN/TAD digester with an effective volume of 23 L for 30 days compared with conventional thermophilic aerobic digestion (TAD). The AN/TAD system can efficiently achieve sludge stabilization on the 16th day with a VS removal rate of 38.1 %. The AN/TAD system was operated at lower ORP values in a digestion period with higher contents of total organic compounds, volatile fatty acids, protein, and polysaccharide in the soluble phase than those of the TAD system, which can rapidly decreased and had low values in the late period of digestion for the AN/TAD system. In the AN/TAD system, intracellular substances had lysis because of initial hydrolytic acidification.

Treatment of Munitions Decomposing Wastewater Using Membrane Biological Reactor

Wastewater from the munitions decomposing process typically contains the widely used explosive-trinitrotoluene (TNT), which is also toxic and mutagenic. Commonly used technologies for degradation of TNT,such as activated carbon adsorption and chemical oxidation, are proved to be feasible but not cost-effective. In this study, the effectiveness of biodegradation of TNT by co-metabolism was evaluated in a hybrid hydrolysis acidification and aerobic membrane bioreactor. After six weeks acclimatization, over 90% TNT was removed with influent TNT concentration ranging between 70-85mg/L. Simultaneously remarkable MLSS concentration increase from 1.4 g/l to 6.9 g/l was observed, which indicated that the acclimatization and incubation of biomass was successful. The membrane effectively prevented loss of sludge and kept large biomass in the reactor, which made the system maintained in a high volume loading rate and low sludge loading rate. The experiment results showed that addition of carbon source was an essential factor in biodegradation of TNT wastewater.

Performance of a Pilot-Scale Hydrolysis Acidification and Improved UASB Process for the Treatment of Alcohol Wastewater: Sludge Granulation and Treatment Efficiency

A system termed hydrolysis acidification-improved upflow anaerobic sludge blanket (HA-IUASB) was developed for alcohol wastewater treatment. The improvements of the UASB were that: a reflux pipe was set below the three-phase separator, and the mud mixture treated by the granular sludge bed returned into the water inlet.The improved UASB starts up completely after 61 days operation and the COD removal rate is between 70~96% during startup stage. The mature granule size reachs 3 mm and the methanogenic bacteria inside are mainly bacillus and cocci through Scanning Electron Microscope (SEM) observation. The treatment efficiency of the improved UASB is high and COD removal rate is 55%~80%. COD removal rate reachs 70%~87% by HA-UASB system under the condition of high concentration alcohol wastewater. CH4 is the main constituent and the percentage is 81.61% according to the gas composition analysis. This study proves that HA-IUASB is a feasible and practical means to treat alcohol wastewater.