Biochemical Oxygen Demand Removal Efficiencies Research Articles

Performance assessment of Al-Rustumiah wastewater treatment plant using multivariate statistical technique

An attempt has been made to assess the performance of the third expansion of the Al-Rustamiya wastewater treatment plant (WWTP). This plant serves approximately 1,500,000 people in east Baghdad city, the capital of Iraq, and the increase of the population in this part of the city has reached about 4 million which led to deterioration in their effluents quality. Furthermore, the plant has no improvement on their processing units. Al-Rustamiya WWTP uses a biological water treatment method known as the activated sludge process with an average wastewater treatment of about 300 million liters. In the present paper, a wastewater quality data of ten years has been subjected to a multivariate statistical technique to identify the most important factors that affect the performance of the plant and estimating its efficiency. The data was collected and examined by the central laboratory of the Al-Rustamiya wastewater treatment plant in the mayoralty of Baghdad. Factor Analysis has been used to assess the important water quality parameters: pH, Total Suspended Solids, Biochemical Oxygen Demand (BOD), and Chemical Oxygen Demand (COD). The results revealed that the major factor that affects the performance is the organic load of raw wastewater and the removal efficiency of the WWTP. Furthermore, the results present that the performance of the current plant system is acceptable exclude for the removal efficiency of BOD below the prescribed limit. As well as, The BOD and COD correlation can evaluate wastewater treatment plant efficiency, aid in prompt intervention, and monitor harmful substances.

The comparison between different types of constructed wetlands for biochemical oxygen demand removal efficiency

This research shows efficiency of constructed wetlands (CWs) to purify waste water in the case of Biochemical Oxygen Demand (BOD). CWs such as surface flow (SF), subsurface flow (SSF), and hybrid (HYB) systems have been compared to provide an analysis about which system has better performance for BOD removal efficiency. Data were collected from different scientific articles and from all over the world. Meta-analysis technique was employed to aggregate data from scientific sources, facilitating hypothesis testing, and comparisons between different types of CWs. All the systems of CWs show satisfactory removal efficiency. HYB systems are shown to be the most efficient. One-way analysis of variance (ANOVA) has been applied to analyze differences between respective CWs using R software. It shows that there is a statistically significant difference between different types of CWs. Post-hoc Tukey?s Honestly Significant Different (HSD) analysis demonstrates a statistically significant difference between SF and HYB systems in the case of BOD removal efficiency. Also, Post-hoc Tukey?s HSD shows statistically significant difference between SSF and SF CWs. On the other hand, Post-hoc Tukey?s HSD does not show statistically significant difference between HYB and SSF CWs. The significant reduction rates for BOD removal efficiency, demonstrates that CWs can be used to diminish this kind of pollution.

Efficient treatment of tannery wastewater through aeration, coagulation, and algal pond.

Tannery wastewater effluents contain many toxic and carcinogenic heavy metals and physiochemical parameters that need to be removed before these effluents enter in the main water bodies or rivers. In this study, the effluents from the tannery industry are treated through aeration, coagulation, and Chlorella vulgaris pond treatment processes for the removal of physiochemical: parameters only. The effect of removal efficiencies (%) was studied on the physicochemical parameters, including salinity, electrical conductivity (EC), total dissolved solids (TDS), turbidity, total suspended solids (TSS), biochemical oxygen demand (BOD), and chemical oxygen demand (COD). The key results showed that the removal of EC, TDS, turbidity, TSS, BOD, and COD was 80.2%, 67%, 81%, 80.8%, 68.6%, and 100%, respectively, in raw wastewater treatment having 25, 50, and 70 g of algae C. vulgaris doses. The removal efficiencies (%) of salinity, EC, TDS, turbidity, TSS, BOD, and COD were 83%, 87.1%, 77.1%, 80%, 40%, 97%, and 98%, respectively, during coagulated wastewater treatment with three doses of algae. The observed improvement in treated wastewater indicated that the removal efficiencies (%) of salinity, EC, TDS, turbidity, TSS, BOD, and COD were 85.7%, 39.3%, 81.3%, 67.8%, 50.3%, 97%, and 98%, with C. vulgaris. This study confirmed that the treatment of tannery wastewater by these processes increased the pollutant removal efficiencies as all the physiochemical parameters were exceeding the permissible limits. This research will be helpful to treat the industrial wastewaters or effluents before it further mixes up in the main water streams. In this way, water quality will be better, aquatic life will be saved, and further researchers can analyze more ways for efficient treatments as they have a baseline data through this study findings. One of the most pollutant sources in terms of both physical and chemical parameters is the produced wastewater from tannery industries. The effluents from tannery industry are treated through aeration, coagulation, and algae ponds treatment processes. These treatment made the tannery wastewater as environmental friendly.

Full-scale integrated skid-mounted plug flow photocatalytic reactor: Treatment of hospital wastewater

A full scale treatment of hospital wastewater (60 m3/day), was newly developed, combining many processes including activated sludge, coagulation-flocculation, and skid-mounted photocatalysis. The tested raw hospital wastewater had the following characteristics: biochemical oxygen demand (BOD): 250–400 mg/L, chemical oxygen demand (COD): 800–1000 mg/L, ammonia nitrogen (NH3-N): 70–100 mg/L, total phosphorus (TP): 3.0–5.0 mg/L, suspended solids (SS): 200–300 mg/L and fecal coliform (FC): 9.2 × 104–1 × 105 MON/L. During more than 3 years the in-situ operation of the average removal efficiency of COD was 90–95% with an effluent value in the range of 35–48 mg/L. The average removal efficiency of BOD, FC, TP, NH3-N, SS, color, and turbidity was in the range of 85–90%, 95–97%, 75–80%, 50–55%, 89–92%, and 95–97%, respectively. The overall operating cost was determined as 3.5 RMB /m3. This innovative technology was evaluated at a full-scale plant, demonstrating that its application was feasible and addressed many environmental concerns. This reactor has the following advantages: modular design, low infrastructure investment and simple operation. More importantly, this could be one of the first commercial photocatalytic reactors.

Challenges to Accurate Estimation of Methane Emission from Septic Tanks with Long Emptying Intervals.

Septic tanks in low- and middle-income countries are often not emptied for a long time, potentially resulting in poor pollutant removal efficiency and increased greenhouse gas emissions, including methane (CH4). We examined the impact of long emptying intervals (4.0-23 years) on the biochemical oxygen demand (BOD) removal efficiency of 15 blackwater septic tanks and the CH4 emission rates of 23 blackwater septic tanks in Hanoi. The average BOD removal efficiency was 37% (-2-65%), and the average CH4 emission rate was 10.9 (2.2-26.8) g/(cap·d). The emptying intervals were strongly negatively correlated with BOD removal efficiency (R = -0.676, p = 0.006) and positively correlated with CH4 emission rates (R = 0.614, p = 0.001). CH4 emission rates were positively correlated with sludge depth (R = 0.596, p = 0.002), but against expectation, negatively correlated with BOD removal efficiency (R = -0.219, p = 0.451). These results suggest that shortening the emptying interval improves the BOD removal efficiency and reduces the CH4 emission rate. Moreover, the CH4 emission estimation of the Intergovernmental Panel on Climate Change, which is a positive conversion of BOD removal, might be inaccurate for septic tanks with long emptying intervals. Our findings suggest that emptying intervals, sludge depth, and per-capita emission factors reflecting long emptying intervals are potential parameters for accurately estimating CH4 emissions from septic tanks.

Prevention of water pollution through combined sewer overflow using high-speed biofiltration in urban watershed

Over recent decades, the rural areas of Korea, including containing source waters, have become extensively developed. Combined sewer systems (CSSs) have been constructed to collect the sewage generated from these areas. Presently, it is common to experience localized heavy rain events, likely due to climate change, and sometimes, the volume of rainfall can become too high for a CSS to handle. In these cases, combined sewer overflow (CSOs) occurs, contaminating surface water, which may have been used as source water. Therefore, the Korean government will begin regulating the biochemical oxygen demand (BOD) of CSOs occurring during first flushes of less than 40 mg/L from 2024 onwards. In this study, a biofiltration-based technology was proposed to treat CSOs. Thus, this study aimed to remove BOD from CSO using this biofiltration system to contain cube-type media. For this, two different loading rates were tested on a pilot scale. Although the proposed system resulted in a footprint of only 10 % of that of a conventional activated sludge system, it was still capable of achieving efficient BOD removal. At a high loading rate, BOD removal efficiency was observed at approximately 53 %, and when this loading rate was reduced by 50 %, the removal efficiency was slightly improved to about 58 %. In both cases, the BODs of treated CSOs could be maintained below the proposed future standard: 31 mg/L and 28 mg/L for high and low loading rates, respectively. Therefore, the proposed system could potentially be preventing environmental contamination from COSs.

Applicability of hybrid treatment to reduce the footprint of domestic and industrial wastewater of developing countries

Wastewater pollution is a serious concern, especially in developing countries such as Pakistan. The untreated domestic and industrial wastewater is typically discharged into sewers, natural drains, or water bodies. There is a dire need to evaluate the applicability of low-cost treatment technologies. Hybrid wastewater treatment (HWWT), comprising of chemically enhanced primary treatment (CEPT) and intermittent sand filter (ISF), was adopted to treat domestic, process and manufacturing, and food industry wastewaters. The wastewater pollution and contamination were assessed in terms of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total suspended solids (TSS). The removal efficiency (RE) performance of HWWT was compared with the CEPT system only. Considering the CEPT only, the RE of BOD was ≈70 % for domestic, >80 % for process and manufacturing, and ≈50 % for the food industry. For COD, the RE was high in process & manufacturing (RE ≈ 81 %), followed by food (RE ≈ 55 %) and domestic wastewater (RE ≈ 17 %). Furthermore, the CEPT provided >95 % TSS removal in all wastewater types. The HWWT increased TSS removal by ≈2 %, BOD removal by ≈13 %, and COD removal by ≈27 % compared to the CEPT system. Therefore, HWWT proved more efficient in treating both domestic and industrial wastewater. The HWWT reduced the greywater footprint (GWF) by 50–60 % when compared to the CEPT system. This study provided knowledge of the characteristics of domestic and industrial wastewater. Furthermore, provides a basis to assess the applicability and performance of various wastewater treatment systems under given settings.

Fabrication of semiconducting photo nano catalyst ZnO/SnO2/ CdS to cleanup the dairy wastewater in sunlight

The creation of three nanoparticles and their use in the photocatalytic degradation of organic contaminants found in dairy effluent is reported here using a sustainable and repeatable process. Physicochemical techniques, including X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and energy dispersive X-ray, were used to characterize the materials. The photocatalytic degradation of methyl violet using three nanoparticles is investigated using a UV–Vis spectrophotometer. Solar radiation and nanoparticles were investigated to improve photocatalysis procedures. The study aimed to determine the effects of concentrated sunlight and combined catalysts on chemical oxygen demand (COD), biochemical oxygen demand (BOD), and bacterial inactivation. The concentrated sun approach achieved 90% and 95% COD and BOD removal efficiency. Comparing all the metal oxide nanoparticles, the combined nanoparticles ZnO/CdS/SnO2 demonstrate significantly better performance in the photocatalytic process. The main objective is to treat dairy wastewater for reuse for various social purposes.

Biomass Fuel Production through Fermentation of Lysinibacillus sp. LC 556247 in Various Ratios of Palm Oil Mill Effluent and Empty Fruit Bunch

Biomass wastes originating from palm oil milling activities can be characterized by their high biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS), and oil and grease content. The utilization of oil palm wastes such as palm oil mill effluent (POME) and empty fruit bunch (EFB) has great potential for a sustainable energy biomass pellet as it reduces the reliance on conventional materials for energy production. A mixture of POME and EFB in various ratios ranging between 7:3, 8:2, 9:1, and 10:0 was fermented in the presence of Lysinibacillus sp. LC 556247 for 120 h at 37 ± 2 °C and 180 rpm with the aim of elucidating the biodegradation of complex organic material in terms of BOD, COD, TSS, total organic carbon, inorganic carbon, and total carbon content. After fermentation, the mixtures were oven dried at 105 °C overnight and then subjected to calorific energy value (CEV) determination. The highest CEV of 20.26 MJ/kg was achieved for a ratio of 10:0 (slightly higher than the control experiment with the value of 18.67 MJ/kg), with maximum removal efficiencies of COD (12.19%), BOD (11.72%), TSS (93.94%), and oil reduction of 17.43%. The addition of EFB did not positively increase the CEV.

Increasing nitrogen and organic matter removal from swine manure digestate by including pre-denitrification and recirculation in single-stage partial nitritation/anammox

A novel two-stage process comprising pre-denitrification and single-stage partial nitritation/anammox was developed to treat swine manure digestate with a constant nitrogen loading rate of 1.0 gN/L/d. As the influent NH4+-N concentration increased from 500 to 1500 mg/L, a nitrogen removal efficiency of 88 %–96 % and 5-day biochemical oxygen demand removal efficiency of 93 %–97 % were achieved. Owing to the high influent chemical oxygen demand (COD)/nitrates and nitrites (NOX) ratio of 8.2–9.2 and high COD utilization of denitrifying bacteria (DB), the NO2−-N and NO3−-N removal efficiencies in the denitrification reactor reached 96 %–99 % and 97 %–99 %, respectively. The contribution of anammox bacteria to nitrogen removal was 70.9 %–84.3 %, whereas that of DB was 11.7 %–18.3 %. The contributions of DB and ordinary heterotrophic organisms to COD removal were 19.5 %–49.3 % and 17.9 %–39 %, respectively. This study will help guide the anammox process in swine wastewater treatment.

Optimization of photocatalytic degradation of biochemical oxygen demand from textile industry effluent using copper oxide nanoparticles by response surface methodology

AbstractThis study aimed at photocatalytic degradation of biochemical oxygen demand (BOD) from the effluent of the Baluch textile factory in Iranshahr (Iran) using copper oxide nanoparticles (CuONPs). The characteristics of CuONPs were analyzed using a scanning electron microscope (SEM), transmission electron microscope (TEM), X‐ray diffraction (XRD) and X‐ray fluorescence (XRF). The results showed that the maximum removal efficiency (90.03%) was related to the state in which the intensity of ultraviolet (UV) was at the highest value (30 W). In this study, high values of coefficient of determination (R2) (99.2%) and adjusted coefficient of determination (adjusted R2) (98.11%) indicated that the very large share of changes in response variables was determined by independent factors. According to the results of analysis of variance, the order of the effect of the factors used in the study were as follows: pH > UV > time > Copper(II) oxide (CuO) dose. The BOD removal efficiency increased when pH was increased from 3 to 7 and contact time was increased from 10 to 60 min. More than 89% of BOD was removed at pH 7 and contact time 60 min. As such, when nanoparticle dose (from 0.02 to 0.05 g/L and contact time from 10 to 60 min) increased, so that the highest removal efficiency (89%) was reported at a dose of 0.05 g/L nanoparticles and a contact time of 60 min. In general, the Langmuir isotherm had a much better fit (R2 = 0.991) than the Freundlich (R2 = 0.9712) and Temkin (R2 = 0.7545) isotherms.

Modeling and optimization of process parametric interaction during high-rate anaerobic digestion of recycled paper mill wastewater using the response surface methodology

Abstract This study carried out the anaerobic digestion of recycled paper mill wastewater (RPMW) in a high-rate novel anaerobic baffled reactor. The parametric interaction between influent chemical oxygen demand (CODin) and hydraulic retention time (HRT) was modeled, and process responses were optimized by the response surface methodology (RSM) using a three-level factorial design. The results showed that the optimal condition was determined at CODin of 4,000 mg/L and HRT of 2 days and predicted values for COD removal, biochemical oxygen demand (BOD) removal, lignin removal, CH4 content, and CH4 production were found to be 94%, 98%, 68%, 85%, and 20.8 L CH4/d, respectively. According to the statistical analysis of the RSM, all models were significant with very low probability values (from 0.0045 to <0.0001). The parametric interaction showed that increasing the CODin positively influenced the COD, BOD, and lignin removal efficiencies, effluent alkalinity, and methane content and production but was unfavorable for pH and effluent volatile fatty acid (VFA). Shortening the HRT negatively affected the COD, BOD, and lignin removal efficiencies, pH level, alkalinity, and methane content and production, and increased the VFA effluent concentration. The optimal conditions were established at 4,000 mg/L COD and HRT of 2 days, corresponding to the predicted COD, BOD, and lignin removal efficiencies of 91, 98, and 71%, respectively, whereas 28 mg/L of VFA and 0.125 L of CH4/g CODremoved were generated.

Computational-Based Approaches for Predicting Biochemical Oxygen Demand (BOD) Removal in Adsorption Process

Predicting the adsorption performance to remove organic pollutants from wastewater is an essential environmental-related topic, requiring knowledge of various statistical tools and artificial intelligence techniques. Hence, this study is the first to develop a quadratic regression model and artificial neural network (ANN) for predicting biochemical oxygen demand (BOD) removal under different adsorption conditions. Nanozero-valent iron encapsulated into cellulose acetate (CA/nZVI) was synthesized, characterized by XRD, SEM, and EDS, and used as an efficient adsorbent for BOD reduction. Results indicated that the medium pH and adsorption time should be adjusted around 7 and 30 min, respectively, to maintain the highest BOD removal efficiency of 96.4% at initial BOD [Formula: see text] mg/L, mixing [Formula: see text] rpm, and adsorbent dosage of 3 g/L. An optimized ANN structure of 5–10–1, with the “ trainlm” back-propagation learning algorithm, achieved the highest predictive performance for BOD removal ([Formula: see text]: 0.972, Adj-[Formula: see text]: 0.971, RMSE: 1.449, and SSE: 56.680). Based on the ANN sensitivity analysis, the relative importance of the adsorption factors could be arranged as [Formula: see text]. A quadratic regression model was developed to visualize the impacts of adsorption factors on the BOD removal efficiency, optimizing pH at 7.3 and time at 46.2 min. The accuracy of the quadratic regression and ANN models in predicting BOD removal was approximately comparable. Hence, these computational-based methods could further maximize the performance of CA/nZVI material for removing BOD from wastewater under different adsorption conditions. The applicability of these modeling techniques would guide the stakeholders and industrial sector to overcome the nonlinearity and complexity issues related to the adsorption process.

Greywater characterization of an Indian household and potential treatment for reuse

• A filtration system with different filter layers was designed. • COD removal efficiency of 85.98%. • BOD removal efficiency of 86.28%. • 94.44% total suspended solids removal efficiency. Inadequate water supplies recall the environmental values of recovery and reuse of limited resources. One of the exciting opportunities in these circumstances is Grey water. Wastewater is generated from household activities like bathing, kitchen sinks, washbasins, and laundry classified as greywater. Inventing a pilot-scale greywater treatment system that treats in-house generated greywater and makes it reusable by assisting the untapped potential of physical methods of greywater purification was the main aim of this study. The study results from greywater samples' characterization from various sources in an Indian middle-class single household with four residents for six months. Moreover, the designing and analyzing of a treatment system applied to treat this in-house generated greywater was conducted. A filtration system with different filter layers was designed. It was found to have a chemical oxygen demand removal efficiency of 85.98%, biochemical oxygen demand removal efficiency of 86.28%, and total suspended solids removal efficiency of 94.44%. The filter system designed in this study describes improved removal efficiency in all respects and gives an idea of the reusability of in-house treated greywater. The study concludes that greywater can be recycled and reused for toilet flushing, gardening, car washing, and firefighting. This practice can also lead to a significant reduction in the consumption of freshwater.

A short review on landfill leachate treatment technologies

The solid waste disposal problem is a well-known global environmental issue, wherein landfilling and open dumping are the most widely followed practices. The production of toxic liquid, leachate, is a significant issue with landfilling practices. This leachate needs to be treated carefully before its disposal in the environment. Landfill leachate is characterized by very high chemical oxygen demand (COD) and biochemical oxygen demand (BOD) consisting of unappealing constituents like toxic organic and inorganic pollutants. In general, leachate parameters such as landfill age, COD/BOD ratio, and COD are the decisive factors in the selection of appropriate treatment methods. The various adopted technologies for leachate treatment are assessed and summarized under heads like biological, physicochemical, and hybrid methods. The purpose of this research is to look at the technological improvements used for landfill leachate treatment, taking into account the lessons learnt over time and the solutions that have been implemented. It was observed that, when the treatment techniques are employed in standalone mode, they are unable to meet the acceptable water quality criteria, nevertheless when the treatment techniques are used in combination, then it meets the stringent criteria for disposal. The integrated biological and physicochemical treatment methods are viewed as critical for adhering to sustainable release limits and ensuring environmental protection by achieving satisfactory COD, BOD, and ammonia nitrogen removal efficiencies. The evaluation includes state-of-the-art research outputs as well as potential combined applications of various treatment strategies covered in previous works.

Assessment of laboratory scale cylindrical sequencing batch reactor for the treatment of abattoir effluent

Meat factory effluent contains fat, protein, diluted blood, and suspended solids. As a result, nutrient and organic concentrations in this effluent are incredibly high, and residues are slightly solubilized, likely to impact environmental pollution on streams, rivers, and other watercourses if discharged untreated. The biodegradation of abattoir waste was studied using a laboratory-scale cylindrical sequencing batch reactor (SBR) in aerobic mode. The aerobic sludge was collected from the aeration compartment of a paper and pulp effluent treatment facility and cultivated in a 2.83-L Perspex-based laboratory SBR. The raw wastewater comprised 6494 ± 2144 mg/l chemical oxygen demand (COD), 1946 ± 607 mg/l biochemical oxygen demand (BOD), 1722 ± 159 mg/l total suspended solids (TSS), 3062 ± 592 mg/l CaCO3 alkalinity, 7.00 ± 0.27 pH. The duration of a complete cycle was 24 h and comprised four phases: fill (5 min), react (23 h 10 min), settle (40 min) and draw (5 min). The whole experiment was divided into four phases and the dilution was done with the help of domestic sewage. In the first stage, the reactor was fed four times diluted slaughterhouse effluent on a 24-h cyclic operation for two weeks. After achieving a significant reduction in COD, the organic content of the input was raised by lowering the dilution factor. In the second and third phases, the reactor was fed three times and twice diluted samples for two weeks each operating at the same cyclic interval. In the final stage, raw effluent was fed to the reactor for two more weeks. The average COD value of diluted wastewater in the first, second, third and fourth phase was 1040 mg/l, 3168 mg/l, 4800 mg/l, and 5200 mg/l, respectively. The COD removal efficiency at the end of the first, second, third and fourth phase was 83%, 93%, 85% and 97%, respectively. The average BOD value of diluted wastewater at the end of the first, second, third and fourth phase was 1120 mg/l, 610 mg/l, 1502 mg/l, and 1350 mg/l, respectively. The BOD removal efficiency at the end of the first, second, third and fourth phase was 84%, 88%, 85% and 98%, respectively. After 8 weeks, at an organic loading rate of 3.06 kg/m3/d, the final phase has achieved BOD and COD removal efficiency of 98% and 97%, respectively. The pH and alkalinity levels were within acceptable ranges. After two months, the sludge's settling characteristics have improved, and the nitrification efficiency of the reactor was roughly 60% at the time of deactivation of the reactor.

Nutrient requirement of tannery wastewater containing tannins

Biological wastewater treatment methods are extensively used in the treatment of industrial effluents among which Activated Sludge Process (ASP) holds a prominent position. To carry out the degradation of organic matter, the micro-organisms present in the activated sludge need sufficient amount of nutrients and oxygen in the aerobic treatment process. Hence, this study was undertaken to assess and optimize the nutrient requirement in the treatment of vegetable tanning process wastewater (VTW) generated from tanneries. The characterization of VTW revealed that the observed Biochemical Oxygen Demand (BOD):Nitrogen (N):Phosphorus (P) ratio of VTW was 100:1.42:0.07, which is deficient in both N and P. Aerobic reactor study was conducted with BOD:N:P ratio of 100:1.42:0.07, 100:5:0.1, 100:5:1, 100:5:3 and 100:5:5 separately. For N:P of 5:0.1, removal efficiencies of BOD 5 , COD and tannin were 49.0 %, 37.3 % and 30.2 %, respectively, whereas, for N:P of 5:3, BOD 5 ,COD and tannin removal efficiency was 59.7 %, 50.9 % and 38.0 %, respectively. However, further increasing the N:P ratio to 5:5, BOD 5 ,COD and tannin removal efficiencies were 60.9 %, 51.2 % and 38.7 %, respectively. It was observed from the results that for N:P ratio of 5:3 to 5:5, the improvement in removal efficiencies was marginal. Hence, BOD:N:P ratio of 100:5:3 was considered as optimum Respirometry study revealed that oxygen uptake was 62.5 mg O 2 during the 24 h and 18 % of MLSS growth was observed. From modified Stover–Kincannon model the kinetic constants U max of 3.74 g/L day and K B of 54.08 g/L.d were arrived at; The k value was obtained from first order and zero order equation was 16.95 mg/L h −1 and 0.026 h −1 , respectively for tannin as substrate for the optimized ratio BOD:N:P ratio of 100:5:3. This study emphasizes that proper balance of N and P is needed for synthesis of sufficient biomass for degradation in biological treatment.

Pilot-Scale Investigation of the Integrated Anaerobic–Aerobic Bioreactor (IAAB) Treating Palm Oil Mill Effluent (POME): Startup and Performance Evaluation

The treatment of palm oil mill effluent (POME) has always been the topic of research in Malaysia due to the high concentration of total suspended solid (TSS) and oil and grease (O&G) ranges from 28 846 to 30 920 mg/L and 5614 to 8812 mg/L, respectively. Additionally, the release of methane gas during the treatment of POME in all of the palm oil mills has been the major contributor to greenhouse gas (GHG) effect. The main aim of this work is to evaluate the performance of the pilot-plant integrated anaerobic–aerobic bioreactor (IAAB) for POME treatment at two different phases: (a) startup and (b) long-term performance evaluation from an organic loading rate (OLR) of 10.5 to 32.5 gCOD/(L·day). Startup of the pilot-plant IAAB was successfully accomplished in 24 days with overall removal efficiencies in terms of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total suspended solid (TSS) of at least 90% at the OLR of 8.0 gCOD/(L·day). The pilot-plant IAAB achieved high BOD, COD, and TSS removal efficiencies of more than 99% for OLR up to 30.0 gCOD/(L·day) with methane yield ranges from 0.0406 LCH₄/gCODᵣₑₘₒᵥₑd to 0.1312 LCH₄/gCODᵣₑₘₒᵥₑd. The effluent quality remained stable with BOD of 16–107 mg/L with a high percent of compliance with the discharge limit of 100 mg/L. The coupling of the Grau second-order and Stover–Kincannon models (anaerobic system) with the Stover–Kincannon model (aerobic system) will completely define the pilot-plant IAAB system. This pilot-plant research will provide valuable data and experiences required to design and commission a full-scale IAAB.

Integration of Improved Methods for the Treatment of Wastewater from a Soft Drink Industry

Beverage companies produce a large amount of wastewater in the cleaning step of returnable glass bottles. This study aimed to investigate combined processes (coagulation/flocculation, adsorption, and membrane separation) to treat the effluent from the washing machine of returnable soft drink bottles. Tests were conducted with aluminum sulfate, ferric chloride, and tannins (TANFLOC®) powder as coagulants/flocculants in different concentrations. After choosing the best coagulant, new tests were repeated by adding activated carbon. Based on the coagulant's best condition and activated carbon mass, the treated samples were subjected to a separation step with the ultrafiltration membrane (UF). The best treatment condition was the combined methods (TANFLOC + activated carbon + UF membrane), which showed a removal efficiency of 63.64, 54.92, and 64.98% for Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), and Biochemical Oxygen Demand (BOD), respectively. The BOD values are due to the presence of sugars in the effluent since its characteristics, such as high polarity and size less than 1 kDa, are unfavorable for the coagulation and UF processes, respectively. However, BOD removal efficiency was approximately 5% higher than the minimum required by legislation, which requires at least a 60% decrease in the raw effluent.

Role of nanoclay surface charge for phytoremediation process enhancement

This study highlights the significance of increasing the phytoremediation treatment of Nelumbo nucifera plant efficiency using treated nanoclay soil to adjust its surface charge. The treated nanoclay consisted of zeta potential values of -11.41, -28.7, and −42.5 mV for pH 4, 6, and 10, respectively. The biochemical oxygen demand (BOD), chemical oxygen demand (COD), and nitrate removals (NO3−) for the reference samples were −6.1 %, −5%, and 10.2 %, respectively, without the plant and soil, on day 5 of observation. With the plant, the biochemical oxygen demand removal efficiency increased to 51.7 % when treated with as-received clay and followed by 78.7 %, 73.7 %, and 77.3 % when treated with nanoclay soil at pH 4, 6, and 10, respectively. The chemical oxygen demand removal efficiency also increased to 32.4 % when treated with as-received soil, followed by 66.7 %, 70 %, 62.7 % when treated with pH 4, 6, and 10, respectively. The significant changes were noticed on the N adsorption capacity represented by the NO3− removal efficiency of as-received clay increased from 18.1%–54.5%, 64.5 %, and 70 % when treated with pH 4, 6, and 10, respectively. Here, we suggest that the surface charge of nanoclay particles in the basic condition is the important step to allow high N adsorption.