Sequencing Batch Reactor Performance Evaluation on Orthophosphates and COD Removal from Brewery Wastewater

In the present study, the removal of phenol from synthetic wastewater was evaluated in a fixed bed reactor with up flow sludge blanket filtration (FUSBF) in comparison with a typical USBF system. At hydraulic retention time (HRT) of 24 hours and solid retention time (SRT) of 20 day, the effect of initial concentration of phenol (260-1020 mg/L) on phenol and chemical oxygen demand (COD) removal efficiency (%) was investigated in both systems. The effect of the presence of fixed bed was determined throughout the operational period.The results showed that the FUSBF system had a better ability than the typical USBF system in terms of phenol and COD removal. The average phenol and COD removal at phenol concentration of 312 mg/L was 97.52% and 92.82% for the FUSBF system and 92.80% and 82.18% for the typical USBF system, respectively. At HRT of 24 h and organic loading rate (OLR) of 30 g/m-3.h-1, the amount of phenol removal was 82.1%. At OLR of 30 g/m-3.h-1, role of fixed bed in phenol and COD removal was 25.01% and 29.3%, respectively, overall, the FUSBF system has a higher efficiency and ability than that of typical USBF and can be used for the purification of industrial wastewater containing refractory organic compounds such as phenol.

While palm oil mill effluent (POME) from different sources will have varying characteristics due to the different process flows in mills, efficient monitoring and performance evaluation of anaerobic digesters in POME treatment are crucial to ensure stable biogas production with minimal operational problems. Therefore, this study aims to evaluate and compare the performances of in‐ground lagoon anaerobic digesters under mesophilic conditions in four different biogas plants (BGPs A, B, C and D) located in Malaysia with respect to total chemical oxygen demand (COD) removal and total biogas produced. Results show that all BGPs are still functioning well with satisfactory methane yields (.135–.364 Nm3CH4/kgCOD removed) and COD removal efficiencies (67%–85%). ANOVA analysis shows that organic loading rate (OLR), temperature (T) and recirculation ratio (RR) have significant effects on the COD removal and biogas production of all four plants. BGP B has the highest amount of biogas produced (4.12 × 105 Nm3/month) and COD removal rate amongst other BGPs due to its most stable and lowest T (<40°C), high RR, and consistent and high COD load. Conversely, BGP D has the lowest COD removal and biogas production, which are mainly contributed by a high COD inlet (92 000 mg/L) and a high T in the anaerobic digester (48.7°C). Despite having a similar design of an anaerobic digester, this comparative study reveals that different BGPs will have different optimum operating conditions and limitations, depending not only on the operating conditions of the BGP (OLR, T and RR) but also on the raw POME quality stemming from the palm oil milling process. A future study would be focused on the optimisation of four BGPs for maximum biogas removal.

The poultry slaughterhouse industry consumes a large volume of potable water for bird processing and equipment cleaning, which culminates in the generation of high strength poultry slaughterhouse wastewater (PSW). The wastewater contains high concentrations of organic matter, suspended solids, nitrogen and nutrients. Most poultry slaughterhouses in South Africa (SA) discharge their wastewater into the municipal sewer system after primary treatment. Due to its high strength, PSW does not meet SA's industrial discharge standards. Discharge of untreated PSW to the environment raises environmental health concerns due to pollution of local rivers and fresh water sources, leading to odour generation and the spread of diseases. Thus, the development of a suitable wastewater treatment process for safe PSW discharge to the environment is a necessity. In this study, a biological PSW treatment process using an Expanded Granular Sludge Bed (EGSB) was evaluated. Response surface methodology coupled with central composite design was used to optimize the performance of the EGSB reactor. The dependant variable used for optimization was chemical oxygen demand (COD) removal as a function of two independent variables, hydraulic retention time (HRT) and organic loading rate (OLR). The interactions between HRT, OLR and COD removal were analysed, and a two factorial (2FI) regression was determined as suitable for COD removal modelling. The optimum COD removal of 93% was achieved at an OLR of 2 g-COD/L/d and HRT of 4.8 days. The model correlation coefficient (R2) of 0.980 indicates that it is a good fit and is suitable for predicting the EGSB's COD removal efficiency.

COD removal from biologically stabilized landfill leachate using Advanced Oxidation Processes (AOPs)

A study of the anaerobic biodegradability of the three categories of water separated from extracted crude oil (Venezuelan oilfields) ‐ light, medium or heavy crude ‐ was carried out at laboratory scale using UASB reactors working at mesophilic conditions. Chemical oxygen demand (COD) removal in a low loaded UASB reactor fed with water separated from extracted light crude was high, with an average 87 % purification efficiency. The remaining COD was made up of the non‐biodegradable and the very slowly biodegradable fractions of the organic matter in the water. During a second period, the hydraulic retention time was reduced in stages, thus increasing the loading rate. In the experimental conditions used, COD concentration at the outlet remained below the Venezuelan standard limit for discharge into the environment (350 mg COD 1‐1) when the hydraulic retention time (HRT) was above 10 hours and the OLR under 3 g COD l‐1 d‐1. For HRT less than 10 hours, or organic loading rate (OLR) greater than 3 g COD I‐1 d‐1, COD at the outlet of the reactor rose as a consequence both of increased volatile fatty acids (VFA) concentrations (indicating an overloading of the methanogenic population) and, also, of the increase in the non‐VFA COD (indicating a decrease in the acidification efficiency). On the other hand, results with UASB reactors operated at a low loading rate and fed with water separated from extracted medium and heavy crude oil showed that purification efficiency was low, with only 20 % and 37 % COD removal respectively. Continuing the operation of the UASB reactor fed with water separated from medium oil over a prolonged period did not bring any improvement, indicating that no adaptation of the sludge occurred.

Anaerobic digestion of wash waters derived from the purification of virgin olive oil using a hybrid reactor combining a filter and a sludge blanket

Perfluorooctane sulfonate decreases the performance of a sequencing batch reactor system and changes the sludge microbial community

BACKGROUND: This study considers batch treatment of saline wastewater in an upflow anaerobic packed bed reactor by salt tolerant anaerobic organisms Halanaerobium lacusrosei.RESULTS: The effects of initial chemical oxygen demand (COD) concentration (COD0 = 1880–9570 mg L−1), salt concentration ([NaCl] = 30–100 g L−1) and liquid upflow velocity (Vup = 1.0–8.5 m h−1) on COD removal from salt (NaCl)‐containing synthetic wastewater were investigated. The results indicated that initial COD concentration significantly affects the effluent COD concentration and removal efficiency. COD removal was around 87% at about COD0 = 1880 mg L−1, and efficiency decreased to 43% on increasing COD0 to 9570 mg L−1 at 20 g L−1 salt concentration. COD removal was in the range 50–60% for [NaCl] = 30–60 g L−1 at COD0 = 5200 ± .100 mg L−1. However, removal efficiency dropped to 10% when salt concentration was increased to 100 g L−1. Increasing liquid upflow velocity from Vup = 1.0 m h−1 to 8.5 m h−1 provided a substantial improvement in COD removal. COD concentration decreased from 4343 mg L−1 to 321 mg L−1 at Vup = 8.5 m h−1, resulting in over 92% COD removal at 30 g L−1 salt‐containing synthetic wastewater.CONCLUSION: The experimental results showed that anaerobic treatment of saline wastewater is possible and could result in efficient COD removal by the utilization of halophilic anaerobic bacteria. Copyright © 2008 Society of Chemical Industry

Increasingly, environmental regulations are demanding more exacting chemical oxygen demand (COD) and nitrogen removal from wastewater, which come at a high economic cost. A very simple novel bioreactor, the micro-pressure swirl reactor (MPSR), can improve the dissolution and distribution of oxygen by the introduced micro-pressure swirl. Comparison with a conventional sequencing batch reactor (SBR) over 76 days of operation showed that this method can enhance simultaneous COD and nitrogen removal. By installing an aeration diffuser on one side of the two-dimensional MPSR, a swirl formed in the bioreactor that extended the retention time of the air bubbles. This unique flow regime, combined with the micro-pressure caused by the elevated water surface at the bubble outflow point, resulted in a higher level of dissolved oxygen (DO) in the MPSR. Aerobic and anaerobic zones that created appropriate conditions for simultaneous COD and nitrogen removal also formed in the MPSR. As the organic loading rate increased from 0.29 to 1.68 g COD/(L · day) over the test period, the COD removal efficiencies of the MPSR were generally 10-20 % greater than those of the SBR. In particular, the total nitrogen (TN) removal efficiencies of the MPSR and SBR were 40-50 and 20-35 %, respectively, whereas the TN concentrations in the MPSR effluent were always around 10 mg/L lower than those of the SBR. Further, because of the unique DO distribution, the bacterial species in the MPSR were more diverse and contributed to enhanced TN removal.

The aim of this paper is to report on the effects of Hydraulic Retention Time (HRT) and Sludge Retention Time (SRT) on the removal of Chemical Oxygen Demand (COD) from palm oil mill effluent (POME). In this study, an upflow anaerobic reactor was used to evaluate the effects of HRT at 6, 8 10, 12 and 15 days. In order to measure the effects of SRT, the 10, 15 and 20 days aged sludge were used. The differences in COD value of POME and effluent at inlet and outlet of the anaerobic reactor were used to measure the effects of HRT and SRT. The experiments were conducted at 35oC for a length of 60 days, and input-output data of COD were used to achieve the research objectives. The estimated results show that the COD removal was optimum at 12 days of HRT and the estimated COD removal performance was at 40.4 percent. It was also found that COD removal was optimum at 20 days of SRT and the estimated COD removal performance was at 34.1 percent. The study concluded that anaerobic reactor is an effective method to remove COD from POME. This study recommends future researches which aim to increase COD removal to level that is economically and environmentally sustainable.

A laboratory-scale sequential batch reactor (SBR) was operated for 5 months on artificial wastewater using co-produced oxygen from a hydrogen proton exchange membrane (PEM) electrolyser. High chemical oxygen demand (COD) removal (>80–85 %) was achieved consistently using a Food to Microorganism (F/M) ratio as high as 1. The effect of dissolved oxygen (DO) concentration, ranging from 1 to 8 mg/L, on COD removal and oxygen uptake rate (OUR) was evaluated. DO concentration was shown to influence bacteria respiration as OUR values increased across the DO range studied. OUR increased linearly from 4.24 to 9.23 mgO2/L/h/g of MLSS with DO concentration of 1 to 8 mg/L respectively, however no effect on COD removal was observed. Microorganism communities were characterized, and significant variation in bacteria communities distribution was observed when increasing the DO concentration along with a decrease in bacteria diversity. The dominant phylum observed during this study were Proteobacteria, Bacteroidetes, and Candidatus Sacharibacteria. Aeration energy expenditures were estimated to be two times lower than for a similar air SBR when keeping DO concentration below 5 mg/L.

During leather processing about 30–50 m3 of tannery effluent (TE) and 150–250 kg of limed fleshings (LF) are generated for every tonne of hides or skins processed. Currently, TE is treated in an individual or common effluent treatment plant, and solid wastes are disposed of without treatment, leading to emission of greenhouse gases. In the present study, an innovative approach of treating limed fleshings after liquefaction (LLF) and TE together in an upflow anaerobic sludge blanket (UASB) reactor has been carried out for generation of green energy in the form of biogas with methane. Further, the effect of the organic loading rate (OLR) on chemical oxygen demand (COD) removal and methane yield has been investigated in an UASB reactor. On the basis of the present study, the maximum COD removal efficiency of 75% with a methane yield of 0.29 m3/kg of COD removed at an optimum OLR of 12 kg m–3 day–1 and hydraulic retention time (HRT) of 24 h was obtained. This innovative approach of combined treatment resulted in an additional methane yield of 37.5% when compared to the methane yield from treatment of tannery wastewater alone in an UASB reactor. Certified emission reductions (CERs) generated have been estimated for combined treatment of TE and LLF in an UASB reactor by replacing open dumping of fleshings for a typical tannery cluster.

Advanced oxidation processes which produce hydroxyl radicals with high oxidation potential have come forward among the methods used in the treatment of industrial wastewaters containing organic pollutants that are difficult to biodegrade. The application of UV rays with the fentanyl reactivity showed that the organic material is more fragmented and the degradation rate is higher. In this study, Fenton process and photo-Fenton process were applied to industrial wastewater of paper. In experimental studies, optimum experimental parameters such as iron ion and hydrogen peroxide concentrations, pH, temperature, reaction time, mixing speed and light intensity were determined and processes were compared. 70% color and 51% chemical oxygen demand (COD) removal in the Fenton process; 96% color and 90% COD removal in the photo-Fenton process were obtained. The addition of UV radiation to the oxidation process resulted in better degradation of organic contaminants and enhanced color and COD removal efficiency. Although the optimum reaction time of the Fenton process was 120 minutes, the optimum reaction time of the photo-Fenton process was 60 minutes.

A literature review has been undertaken to investigate the performance of the different anaerobic process configurations and operational conditions used in poultry and livestock waste treatment. The results of the extensive literature review showed that a wide range of different reactor volumes varying from 100 mL to 95 m3 were utilized in the investigation of anaerobic processing of poultry manure. Retention times studied were between 13.2 h and 91 days. Most of studies were carried out under mesophilic conditions maintained between 25 and 35 degrees C. Chemical oxygen demand (COD) removals and organic loading rate (OLR) ranged from 32 to 78%, and from 1.1 to 2.9 kg COD m(-3) day(-1), respectively. Biogas yields were achieved between 180 mL g(-1) COD added and 74 m3 day(-1) for a wide range of different reactor configurations. Up-flow anaerobic sludge blanket (UASB) seems to be a suitable process for the treatment of poultry manure wastewater and the liquid fraction of hen manure, due to its ability to maintain a sufficient amount of active biomass. The literature review showed that various reactor configurations such as fixed-film reactor, attached-film bioreactor, anaerobic rotating biological reactor, batch reactors, downflow anaerobic filter, fixed dome plant, UASB, continuously stirred tank reactor (CSTR), up-flow anaerobic filter (UAF), temperature-phased anaerobic digestion (TPAD), anaerobic hybrid reactor (AHR), and two-stage anaerobic systems are well suited to anaerobic processing of cattle manure. At both mesophilic and thermophilic conditions, high COD removals (87-95%) were achieved for treatment of cattle manure wastewaters. The COD and volatile solids (VS) reductions obtained were 37.9 to 94% and 9.6 to 92%, respectively. During the studies, OLR and retention times ranged between 0.117 and 7.3 g VS L(-1) day(-1) and between 0.5 and 140 days, respectively. In anaerobic processing of cattle manure, methane yields between 48 mmol CH4 L(-1) and 4681.3 m3 CH4 month(- 1) were found for the corresponding reactor volumes of 120 mL and 1300 m3, respectively. In anaerobic processing of swine manure, OLR ranged from 0.9 to 15.42 g VS L(-1) day(- 1) at mesophilic conditions (25-35 degrees C). The reactor volumes varied between 125 mL and 380 L. Temperature and retention times ranged from 25 to 60 degrees C, and 0.9 to 113 days, respectively. COD and VS reductions achieved were between 57 and 78% and between 34.5 and 61%, respectively. Moreover, methane yields were obtained between 22 and 360 mL CH4 g(-1) VS added. The results showed that UASB, anaerobic baffled reactors, CSTR, and anaerobic sequencing batch reactor (ASBR) were successfully utilized in anaerobic processing of swine manure at both mesophilic and thermophilic conditions.

Evaluation of COD and turbidity removal from woodchips wastewater using biologically sequenced batch reactor