Continuous Biological Treatment Research Articles

Autonomous Pilot Plant for Continuous Biological Treatment of Sulphide Alkali Wastewater.

The article considers an autonomous pilot plant that performs continuous biological wastewater treatment in the event of emergencies at biological treatment facilities, as well as modeling the operation of biological treatment facilities when the composition of incoming wastewater changes.

Отмена ингибиторов фактора некроза опухоли-α при достижении лекарственной ремиссии ювенильного идиопатического артрита без системных проявлений

Juvenile idiopathic arthritis (JIA) is one of the most common and disabling rheumatic diseases in children. Pharmaceutical therapy for JIA can prevent the progression of the disease, achieve long-term remission, and significantly improve the quality of life in most patients. In cases where the initial therapy for JIA is not effective enough, it is recommended to escalate it, and vice versa, when remission is achieved, the de-escalation of therapy may be discussed. The latter is necessary due to the high risk of developing infectious complications and certain oncological diseases against the background of continuous biological treatment of JIA, as well as the negative impact of regular injections and/or infusions of medications on the quality of life, the interruption of educational process, the psychological burden of “lifelong” treatment with medications, and the economic burden on families and healthcare system. Currently, optimal regimens for the discontinuation of biopharmaceuticals, including TNFalpha inhibitors, remain a matter of debate. In this regard, the search for potential predictors of JIA exacerbation after withdrawal of biopharmaceuticals is relevant. Key words: juvenile idiopathic arthritis, biologic-free remission of JIA, tumor necrosis factor, inhibitors, etanercept, adalimumab, withdrawal, exacerbation, predictors

Three-Stage Biological System for Treatment of Coke Oven Effluent

AbstractA three-stage continuous biological treatment system has been developed for removal of cyanide, phenol, organics, and ammonia from a coke oven effluent. Two stages of activated sludge treat...

Effect of dilution rate on dynamic and steady-state biofilm characteristics during phenol biodegradation by immobilized Pseudomonas desmolyticum cells in a pulsed plate bioreactor

Pulsed plate bioreactor (PPBR) is a biofilm reactor which has been proven to be very efficient in phenol biodegradation. The present paper reports the studies on the effect of dilution rate on the physical, chemical and morphological characteristics of biofilms formed by the cells of Pseudomonas desmolyticum on granular activated carbon (GAC) in PPBR during biodegradation of phenol. The percentage degradation of phenol decreased from 99% to 73% with an increase in dilution rate from 0.33 h–1 to 0.99 h–1 showing that residence time in the reactor governs the phenol removal efficiency rather than the external mass transfer limitations. Lower dilution rates favor higher production of biomass, extracellular polymeric substances (EPS) as well as the protein, carbohydrate and humic substances content of EPS. Increase in dilution rate leads to decrease in biofilm thickness, biofilm dry density, and attached dry biomass, transforming the biofilm from dense, smooth compact structure to a rough and patchy structure. Thus, the performance of PPBR in terms of dynamic and steady-state biofilm characteristics associated with phenol biodegradation is a strong function of dilution rate. Operation of PPBR at lower dilution rates is recommended for continuous biological treatment of wastewaters for phenol removal.

Continuous treatment of flotation collector wastewater using a membrane bioreactor.

Aniline aerofloat (DDA) is a widely used material in China and has become a main pollutant in floatation wastewater. In this study, a membrane reactor (MBR) was constructed to continuously treat simulated wastewater contaminated with DDA. The study investigated the hydraulic retention time (HRT) and the impact of influent DDA concentration on MBR performance, and analyzed intermediates from the DDA biodegradation pathway and activated sludge transfer pathway. The results showed that a 3 h HRT was an efficient and economical time period for MBR to remove 95 ± 5 mg/L DDA from the simulated wastewater; the chemical oxygen demand reduction rate was 89.9%. DDA concentration negatively impacted MBR performance. MBR performance fluctuated slightly when HRT was 3 h, dissolved oxygen ranged from 4.8 to 5.3 mg/L, pH was between 6.5 and 7.0, and DDA concentrations were at 95 ± 5 mg/L DDA. The transfer pathway in the activated sludge of DDA was through soluble microbial products, loosely bound extracellular polymeric substances, tightly bound extracellular polymeric substances, and finally cell biodegradation. DDA initially degraded to aniline; the aniline was further biodegraded to other organic compounds and was finally mineralized through the tricarboxylic acid cycle. This study offers a new continuous biological treatment technology to address DDA.

Continuous Biological Treatment of Paperboard Mill Wastewater along with Hydrogen Production

Continuous biological treatment of paperboard mill wastewater under changes of organic loading rate (OLR) along with hydrogen production was investigated. The continuous experiments were conducted at different OLRs from 1.2 to 18.6kg COD/L.d. The COD removal efficiency increased from 30.8±3.1 to 83.6±5.3% with decreasing OLR from 18.6 to 1.2kg COD/L.d, respectively. TSS, VSS, and carbohydrates removal efficiencies were 86.5±5.11%, 81.6±1.7%, and 63.5±19%, respectively. Meanwhile, the hydrogen production rate was amounted the highest value of 4.74±0.9 L/d at OLR of 9.3kg COD/L.d which coincided to the highest volatile fatty acids of 337±13.6mg/l and HAc/HBu of 2.13±0.4.

Continuous Biological Treatment of Membrane Concentrates of Deinking Wastewater Streams from Pulp and Paper Industry

Continuous Biological Treatment of Membrane Concentrates of Deinking Wastewater Streams from Pulp and Paper Industry

Continuous treatment of coloured industry wastewater using immobilized Phanerochaete chrysosporium in a rotating biological contactor reactor

Coloured industry wastewaters often contain dyes and other toxic ingredients, and, therefore, pose serious threat to the receiving environment. Among the available methods the eco-friendly biological method has gained maximum attention due to its many advantages over the traditional methods. In the present study, continuous biological treatment of coloured wastewater from a textile dyeing industry was investigated using the white rot fungus Phanerochaete chrysosporium in a rotating biological contactor (RBC) reactor. The raw wastewater was diluted with an equal volume of either distilled water or media containing glucose at varying concentrations to study its effect on the decolourization process. Results revealed that the wastewater could be decolourized to an extent of more than 64% when diluted with media containing glucose; and, a maximum decolourization efficiency of 83% was obtained with 10g/l glucose concentration. COD removal efficiencies were also found to be consistent with the decolourization efficiencies of the wastewaters. Further, the results were correlated with the enzyme activities of manganese peroxidase (MnP) and lignin peroxidase (LiP) by the fungus, which were found to play some significant role in decolourization of the wastewater. Results of replacing the costly carbon source glucose in the decolourization media with the more cheap molasses, however, revealed very high COD removal efficiency, but low decolourization efficiency of the industry wastewater.

Detoxification of wastewater containing five common pesticides by solar AOPs–biological coupled system

A mixture of five pesticides commonly used in intensive agriculture in the southeast of Spain, Methomyl, Dimethoate, Oxamyl, Cymoxanil and Pyrimethanil, has been completely mineralized in a combined solar photocatalytic–biological pilot plant. Two advanced oxidation processes (AOPs: TiO 2 and photo-Fenton) were employed for enhancing the biodegradability of wastewater and an aerobic immobilised biomass reactor (IBR) was used for the following continuous biological treatment. TiO 2 photocatalysis experiments were performed in a 35-L solar pilot plant made up of three compound parabolic collectors (CPCs), whereas photo-Fenton tests were carried out in a 75-L solar pilot plant with four CPCs units. The initial pesticide concentrations in the mixture were 50 mg L −1 each. The TiO 2 catalyst concentration employed was 200 mg L −1, and two different Fe 2+ concentrations, 20 mg L −1 and 55 mg L −1, were used in the photo-Fenton tests. Toxicity ( Vibrio fischeri) and biodegradability assays (Zahn-Wellens test) were also performed to monitor toxicity and biodegradability of samples at different stages of photo-Fenton treatment. Biodegradable compounds generated during the preliminary oxidative process were mineralized in a 60-L activated sludge biological reactor filled with 30 L of propylene Pall Ring supports. Total disappearance of the parent compounds, more than 90% mineralization and complete nitrification were achieved by the combined system.

A Direct Comparison of U.S. Environmental Protection Agency's Method 304B and Batch Tests for Determining Activated‐Sludge Biodegradation Rate Constants for Volatile Organic Compounds

Biodegradation rate constants for volatile organic compounds (VOCs) in activated‐sludge systems are needed to quantify emissions. One current U.S. Environmental Protection Agency method for determining a biodegradation rate constant is Method 304B. In this approach, a specific activated‐sludge unit is simulated by a continuous biological treatment system with a sealed headspace. Batch experiments, however, can be alternatives to Method 304B. Two of these batch methods are the batch test that uses oxygen addition (BOX) and the serum bottle test (SBT). In this study, Method 304B was directly compared to BOX and SBT experiments. A pilot‐scale laboratory reactor was constructed to serve as the Method 304B unit. Biomass from the unit was also used to conduct BOX and modified SBT experiments (modification involved use of a sealed draft‐tube reactor with a headspace recirculation pump instead of a serum bottle) for 1,2‐dichloroethane, diisopropyl ether, methyl tertiary butyl ether, and toluene. Three experimental runs ‐ each consisting of one Method 304B experiment, one BOX experiment, and one modified SBT experiment ‐ were completed. The BOX and SBT data for each run were analyzed using a Monod model, and best‐fit biodegradation kinetic parameters were determined for each experiment, including a first‐order biodegradation rate constant (K1). Experimental results suggest that for readily biodegradable VOCs (i.e., K1 > 10 L/g volatile suspended solids [VSS]•h) the two batch techniques can provide improved means of determining biodegradation rate constants compared with Method 304B. In particular, these batch techniques avoid the Method 304B problem associated with steady‐state effluent concentrations below analytical detection limits. However, experimental results also suggest that the two batch techniques should not be used to determine biodegradation rate constants for slowly degraded VOCs (i.e., K1 < 0.1 L/g VSS•h).

Treatment of photographic processing wastewater using anaerobic-aerobic biofilm reactor

Two types of anaerobic-aerobic biofilm processes were applied to the treatment of the photographic processing wastewater. Two-phase fixed bed reactor packed with sponge cubic media and completely mixing three-phase fluidized bed reactor, respectively, were used as an anaerobic and aerobic biofilm reactors. One of the aerobic biofilm reactors was packed with cement balls (CB) made by crushed cement particles, and another packed with biological activated carbon (BAC). The fivefold diluted photographic processing wastewater, from which Ag had been removed previously, was used as an influent (BOD 5,700 g/m3, CODcr 17,000 g/m3, T-N 2,600 g/m3). During long-term continuous biological treatment, BOD values in effluent decreased gradually and reached 280 g/m3, which could fulfill the sewage discharge control value in Japan (BOD < 600 g/m3). It took more than one year to acclimatize the sludge and to get the effective microorganisms for degrading the compounds in the photographic processing wastewater. However, pH values in the aerobic biofilm reactors fell down to 3∼4. This was possibly because thiosulfate (5,700 g/m3) in the photographic processing wastewater was almost oxidized to sulfate by sulfur-oxidizing bacteria. For the purpose of obtaining higher BOD removal efficiency, pH in the aerobic biofilm reactor was adjusted to 7 using pH controller. As a result, BOD removal ratio was gradually improved, and the sewage discharge control value was steadily achieved after 181 days. The number of bacteria in the anaerobic biofilm reactor and the aerobic biofilm reactor with pH controller were 6.0×109 N/mL and 1.1×108 N/mL, respectively.

Treatment of photographic processing wastewater using anaerobic-aerobic biofilm reactor

Two types of anaerobic-aerobic biofilm processes were applied to the treatment of the photographic processing wastewater. Two-phase fixed bed reactor packed with sponge cubic media and completely mixing three-phase fluidized bed reactor, respectively, were used as an anaerobic and aerobic biofilm reactors. One of the aerobic biofilm reactors was packed with cement balls (CB) made by crushed cement particles, and another packed with biological activated carbon (BAC). The fivefold diluted photographic processing wastewater, from which Ag had been removed previously, was used as an influent (BOD 5,700 g/m3, CODcr 17,000 g/m3 , T-N 2,600 g/m3). During long-term continuous biological treatment, BOD values in effluent decreased gradually and reached 280 g/m3, which could fulfill the sewage discharge control value in Japan (BOD < 600 g/m3). It took more than one year to acclimatize the sludge and to get the effective microorganisms for degrading the compounds in the photographic processing wastewater. However, pH values in the aerobic biofilm reactors fell down to 3–4. This was possibly because thiosulfate (5,700 g/m3) in the photographic processing wastewater was almost oxidized to sulfate by sulfur-oxidizing bacteria. For the purpose of obtaining higher BOD removal efficiency, pH in the aerobic biofilm reactor was adjusted to 7 using pH controller. As a result, BOD removal ratio was gradually improved, and the sewage discharge control value was steadily achieved after 181 days. The number of bacteria in the anaerobic biofilm reactor and the aerobic biofilm reactor with pH controller were 6.0×109 N/mL and 1.1×108 N/ mL, respectively.

Biological treatment of wastewater from urea plants of Kuwait

A qualitative and quantitative study of the pollutants in the hydrolyzer effluent of the Petrochemical Industries Company (PIC) was undertaken.This task involved flow measurements coupled with a routine and intensive collection of wastewater samples, a comprehensive analysis for the determination of a set of 6–11 parameters and 10 heavy metals, and statistical analysis of the results.The results showed that despite process optimization of the hydrolyzer plant, the average concentration of ammonia and urea in the hydrolyzer effluent were 100 and 130 mg/l, respectively. The biological treatment studies were aimed at removing urea and ammonia in batch and continuous systems.Biological treatment in the batch system indicated that hydrolyzer effluent was a nutritionally deficient medium to sustain microbial growth, hence supplementation with optimum levels of nutrients was a prerequisite for high treatment efficiency. Kinetic studies were undertaken to optimize nitrification — denitrification and urea biodegradation. The observed rates of nitrification, denitrification, urea and combined nitrogen bio-oxidation rates were comparable to or sometimes better than the corresponding rates reported in the literature.In a continuous biological treatment system urea and ammonia could be completely removed from the hydrolyzer effluent at a hydraulic retention time of 20–24 hours and a solids retention time in excess of 30 days.The average concentrations of ammonia, nitrite, nitrate and urea in the final effluent were 0.3, 0.21, 0.4 and 0.0 mg/l, respectively; the total dissolved solids were 450 mg/l.