Optimization of three operating parameters for a two-step fed sequencing batch reactor (SBR) system to remove nutrients from swine wastewater.

Reducing excess sludge volume in sequencing batch reactor by integrating ultrasonic waves and ozonation.

Abstract. In this study, a two-step fed sequencing batch reactor (SBR) was employed to treat dairy manure wastewater to remove nutrients, including nitrogen, phosphorus, 5-day biochemical oxygen demand (BOD5), and chemical oxygen demand (COD), and to examine the associated nitrous oxide (N2O) emission by the SBR treatment. The SBR was operated on an 8 h cycle with preset time periods for different phases, including anoxic/anaerobic/aerobic phases. The results showed that the SBR system could effectively reduce the nutrients in the wastewater, with removal efficiencies reaching 86.6%, 95.6%, 98.8%, 100%, 97.9%, 95.6%, and 99.8%, respectively, for volatile solids (VS), volatile suspended solids (VSS), total Kjeldahl nitrogen (TKN), ammonium nitrogen (NH4+-N), total phosphorus (TP), COD, and BOD5. However, the SBR could not complete denitrification at the end of the cycle, with 12 mg L-1 nitrate left in the effluent, possibly due to suppression of denitrifiers by the anoxic/aeration phase that was placed almost at the end of cycle and overprovided oxygen to the liquid. Denitrification was found to be a major process for N2O generation, so reducing denitrification time in the cycle is recommended, given that the overall performance of the SBR system in removing nutrients was not compromised. Using oxidation-reduction potential (ORP) alone to automate the SBR control was not sufficient to avoid failure of the system. Keywords: Dairy manure wastewater, Nitrous oxide emission, Nutrient removal, ORP control, Sequencing batch reactor, Two-step fed strategy.

Wastewater treatment using Sequencing Batch Reactor (SBR) technology is one of the state-of-the art wastewater management systems. In this technology equalization, biological treatment and secondary clarification are performed in a single reactor in a time control sequence. SBR system is idler for the areas where the available land is limited, since it operates in less space and very cost effective even on small scales. The control of the operational parameters during the process of biological wastewater treatment is often complicated due to the dynamic change in the composition and characteristics of the raw wastewater, flow rates and other parameters influencing the complex nature of the treatment process and the process in SBR has a unique cyclic batch operation. The performance of the SBR was studied using pilot and real plant at Puducherry. The parameters considered in this study are flow, Mixed Liquor Suspended Solids (MLSS), pH, temperature, influent and effluent of Total Suspended Solids (TSS), Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD). As a part of the study, the effect of constant flow and varying flow on the organic loading of the influent TSS, BOD and COD and their influence on the organic load of the effluent parameters were examined to identify the level of significance of the parameters in relation to the flow. The impact of flow on other parameters was also examined. The experimental data obtained from pilot and real plants were analyzed using multi variate statistical analyses like correlation analysis, Principal Component Analysis (PCA) and Analysis of variance (ANOVA). The statistical analysis revealed that constant flow had no significant role and the influent parameters alone had the critical role, whereas varying flow as well as the influent parameters had the significant role on the performance of SBR.

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

Modeling of effluent quality parameters in a submerged membrane bioreactor with simultaneous upward and downward aeration treating municipal wastewater using hybrid models

This research investigated the pollutant removal efficiencies in swine farm wastewater with Vetiveria zizanioides (L.) Nash (Sri Lanka ecotype) in a surface flow constructed wetland (SFCW). The SFCW units were set up to 3 treatments at 10, 15 and 30 cm water levels to find the proper depth for vetiver grass in wastewater treatment. The water quality indicator such as pH, temperature (T), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total kjeldahl nitrogen (TKN), total phosphorus (TP) and heavy metals (Cu, Fe, Pb, Zn) were analyzed and compared with terms of removal efficiency. The 30 cm water depth has a better removal efficiency of organic substance treatment (BOD and COD). The BOD, COD, TKN and TP removal efficiency had no statistically significant differences between the water depths. TP has the best removal efficiency with average 95.18-96.53%. The treatment of heavy metals such as Cu, Pb, Fe and Zn with vetiver grass in different water depths was showed no statistical significance since it can reduce only a small number of these metals. However, the results showed that the effluent from all the treatment units contained averages of BOD, COD, TKN and pH that followed Thailand’s swine wastewater quality standard.

Aeration control strategy design based on dissolved oxygen and redox potential profiles for nitrogen and phosphorus removal from sewage in a sequencing batch reactor

The Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) predicted that recent extreme hydrological events would affect water quality and aggravate various forms of water pollution. To analyze changes in water quality due to future climate change, input data (precipitation, average temperature, relative humidity, average wind speed and sunlight) were established using the Representative Concentration Pathways (RCP) 8.5 climate change scenario suggested by the AR5 and calculated the future runoff for each target period (Reference:1989-2015; I: 2016-2040; II: 2041-2070; and III: 2071-2099) using the semi-distributed land use-based runoff processes (SLURP) model. Meteorological factors that affect water quality (precipitation, temperature and runoff) were inputted into the multiple linear regression analysis (MLRA) and artificial neural network (ANN) models to analyze water quality data, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), total nitrogen (T-N) and total phosphorus (T-P). Future water quality prediction of the Anseongcheon River basin shows that DO at Gongdo station in the river will drop by 35% in autumn by the end of the 21st century and that BOD, COD and SS will increase by 36%, 20% and 42%, respectively. Analysis revealed that the oxygen demand at Dongyeongyo station will decrease by 17% in summer and BOD, COD and SS will increase by 30%, 12% and 17%, respectively. This study suggests that there is a need to continuously monitor the water quality of the Anseongcheon River basin for long-term management. A more reliable prediction of future water quality will be achieved if various social scenarios and climate data are taken into consideration.

Background: The discharge of untreated wastewater containing toxic and resistant compounds into the environment is a serious threat for ecosystems. Therefore, this study was conducted to evaluate the treatment of poison production factory wastewater using heterogeneous catalytic ozonation process (COP). Methods: Magnetic carbon nanocomposite was used as a catalyst at concentrations of 1, 2, and 4 g/L. Its effect on improving the treatment process was evaluated at reaction time of 30, 60, 90, and 120 minutes. At the end of each experiment, parameters including total organic carbon (TOC), chemical oxygen demand (COD), biological oxygen demand (BOD5 ), pH, electrical conductivity (EC), and turbidity were measured. Results: It was revealed that in single ozonation process (SOP), the maximum removal efficiencies of TOC, COD, and BOD5 were achieved at reaction time of 120 minutes as 56%, 40%, and 11.7%, respectively. By adding the catalyst to the wastewater, the treatment process was improved, so that the maximum removal efficiencies of COD (91%), TOC (73%), and BOD5 (74%) were obtained at catalyst concentration of 4 g/L. Under this condition, BOD5 /COD ratio increased from 0.22 to 0.64. Also, the results of analysis of ozone consumption per each mg of reduced COD showed that its amount sharply decreased from 2.1 mgO3 / mg COD removal in the SOP, to 0.34 mgO3 /mg COD removal in the COP. The results of kinetic reaction analysis also revealed that the rate constant increased from 0.007 to 0.02 min-1. Conclusion: According to the results, it can be concluded that the COP at a catalyst concentration of 4 g/L, by decomposing resistant compounds and increasing the biodegradability, can be used as a suitable pretreatment method for biological processes.

Problem statement: Shrimp farming has rapidly developed in coastal areas of the World Heritage-listed Ha Long Bay since the last decade. Effluent discharged from shrimp farms with high levels of nutrient waste may cause eutrophication in receiving waterways. Therefore, assessing water quality at tidal creeks receiving shrimp farm effluent in coastal areas of Ha Long Bay supports environmental protection and decision making for sustainable development of the region. Approach: Water samples were collected at 3 different locations for spatial assessment: inside sections of creeks directly receiving farm effluent (IEC), from main creeks adjacent to points of effluent discharge outside concentrated shrimp farms (OEC) and a few kilometers away from shrimp farm (ASF). Samples were taken on 3 occasions for temporal assessment. Parameters related to nutrient waste from shrimp farms, including: Total Ammonia Nitrogen (TAN), Nitrite-Nitrogen (NO2-N), Nitrate-Nitrogen (NO3-N), Total Phosphorus (TP), Dissolved Orthophosphate (PO4-P), Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solid (TSS), Chlorophyll-a (Chl-a), Temperature, Salinity, pH and Dissolved Oxygen (DO) were determined using standard methods. Results: There were statistically significant differences in the concentrations of TAN, NO2-N, NO3-N, TP, PO4-P, BOD, COD and Chl-a among IEC, OEC, ASF and the levels of these parameters increased after shrimp crops, especially after the main shrimp crop of the season in North Vietnam. The concentrations of TAN, NO3-N, TP, BOD, COD, Chl-a, TSS at IEC sites were higher than recommended for protecting aquatic ecosystems. Principal Component Analysis (PCA) efficiently summarized patterns of co-variation in water quality parameters among locations and study times. Conclusion/Recommendations: The findings of this study indicate that greater awareness of the environmental impacts of shrimp farms is required if this industry is to be sustainable and if the highly valued marine ecosystem of Ha Long Bay is to be protected for the future.

Biosensor for rapid phosphate monitoring in a sequencing batch reactor (SBR) system

The changes of nitrogen (NH4 +-N, NO2 −-N, and NO3 −-N), chemical oxygen demand (COD), dissolved phosphorus (DP), dissolved oxygen (DO), oxidization and reduction potential (ORP), and pH were tracked in a twice-fed sequencing batch reactor (SBR) treating swine wastewater at aeration intensities of 2.1, 4.2, and 6.3 L/m3 · s, with two alternating non-aeration/aeration phases. The SBR was fed at the beginning of each non-aeration phase with a volume ratio of 3:1. The results show that aeration intensity has positive effects on DO breakthrough and the maximum DO concentration during aeration. Additionally, nitrification, proceeding in an aerated environment with non-detectable DO, can be accelerated when aeration intensity increases from 2.1 to 4.2 L/m3 · s, while the COD and DP removals increase at the end of the aeration phase for higher aeration intensities (4.2 and 6.3 L/m3 · s). Online monitoring results indicate that pH is more sensitive than ORP in revealing the nitrification termination with non-detectable DO, whereas minimal ORP in the non-aeration phase has potential to be used as a control parameter for feeding.

A Sequencing Batch Reactor (SBR) was used to reduce the concentration of organic parameters, that consisted of Chemical Oxygen Demand (COD), Total Nitrogen (N Total) and Total Suspended Solid (TSS) in an apartment wastewater, because the SBR system had a high space efficiency and was low in cost. The apartment wastewater was especially from the effluents of water closets and kitchen. In this study, we applied the SBR method and added activated carbon powder to treat apartment wastewater which had previously gone through the first settling process. This SBR was operated with various hydraulic retention times (HRT) which were 12, 24 and 36 hours respectively, and aeration rates of 3.5 and 7 L/min. Dissolved Oxygen (DO) testing was carried out at each stage of SBR, which aimed to measure and maintain stability at each stage of SBR. The results of the study were the optimum HRT and aeration rate, which were 36 hours and 7 L/min respectively. FTIR test was carried out to determine the efficiency of activated carbon addition in this SBR process. It was found that Activated Carbon increased SBR performance as evidenced by the COD removal rate reaching 89.5% and Total N 94.54%.

A two-step fed SBR for treating swine manure

This study aimed to evaluate the water quality of the Goksu Lake, which is located in Ankara, Turkey. For this purpose, multivariate statistical analyses, namely, principal component analysis/factor analysis, regression analysis and cluster analysis, and linear regression analysis, were used to determine the relationship between the nutrients. In order to evaluate the status of the lake water quality, the limiting nutrient element was determined using the total nitrogen to total phosphorus ratio (TN/TP). The water quality parameters were selected as pH, turbidity, chemical oxygen demand (COD), suspended solids (SS), dissolved oxygen (DO), biochemical oxygen demand (BOD), total nitrogen (TN), chlorophyll-a (Chl-a), total phosphorus (TP), color, fecal coliform (FC), and total coliform (TC) count. For the cluster analysis, the single-link clustering method using Euclidean distance criteria was preferred. Cluster I consisted of sites 1, 2, 3, and 4, while cluster II consisted of site 5. Two factors were obtained as a result of the factor analysis. These two factors explained 88.2% of the total variance. The first factor clarifies the 45.62% of total variance has pH, COD, DO, TN, TP, color, BOD, and TC strong positive load value. This factor was thought to represent domestic wastewater. The second factor that affects water quality clarifies the 42.54% of total variance has turbidity, SS, Chl-a, and FC strong positive load value. This factor was thought to represent the microbiological activities that occurred as a result of the mixing of wastewaters and also pollution accumulating in the bottom sediment. The nutrient-limiting elements in the water lake quality are determined with TN/TP ratio. Accordingly, the lake water quality was determined as N-limited at two points and co-limited at three points. The relationship between the nutrients was evaluated using regression analysis.