BOD Removal Research Articles

Ciprofloxacin Removal from Aqueous Media Using Floating Treatment Wetlands Supported by Immobilized Bacteria

The unwanted occurrence of antibiotics in the environment is an emerging concern of non-target toxicity and antimicrobial resistance. Floating treatment wetland (FTW) is a low-cost and ecofriendly wastewater remediation strategy; however, the effect of immobilized bacteria on its efficacy during the remediation of ciprofloxacin (CIP)-contaminated water has not been documented. In this study, Phragmites australis was planted to develop FTW, and it was augmented with a bacterial consortium (Acinetobacter lwoffii ACRH76, Bacillus pumulis C2A1, and Acinetobacter sp. HN3), with and without immobilization for the remediation of CIP-contaminated (100 mg L−1) water. The augmentation of bacteria (immobilized or in suspension) in the FTWs significantly increased the elimination of CIP from the water. Maximum removal of CIP (97%), COD (92%), BOD (93%), and TOC (90%) from the water was observed in the FTWs having immobilized bacteria. This research revealed that the FTWs have tremendous potential to remove the CIP from the water and its removal efficiency can be enhanced via immobilized bacterial augmentation strategies.

Aeration model for submerged membrane bioreactor – Characterization, oxygen transfer rate, pollutant removal, and energy consumption

The present study uses the Activated Sludge Model-1 and Hydromantis GPS-X modelling software to develop an aeration model for a submerged membrane bioreactor. PVDF membranes with an individual surface area of 10 m2 are used for the experiments. The Activated Sludge Model-1 method investigates the coarser and fine bubble aeration (FBA) systems. According to the study, the FBA system produced significantly better oxygen transfer efficiency and used considerably less energy to perform. The effect of fine and coarse bubble aeration on oxygen transfer efficiency study shows that fine bubble aeration produced 2.1 kg O2/kWh, which is higher than coarse bubble aeration 1.5 kg O2/kWh. The pollutant removal efficiency based on fine bubble aeration shows that the COD, BOD, TN, and TSS removal is obtained at around 93.97%, 96.61%, 95.30%, and 99.70%, respectively. According to the energy consumption assessment, FBA needed 135 kWh/m3, and coarse bubble aeration required 230 kWh/m3, representing 26.21% and 44.66%, of energy requirement, respectively. According to the experimental results, coarse bubbles needed 18.45% more energy for the same permeation. Furthermore, the influence of fine and coarse bubble aeration on membrane fouling found that membrane in FBA systems are less prone to fouling than in coarse bubble aeration systems.

A novel two-stage process for the effective treatment of swine wastewater using Chlorella sorokiniana AK-1 based algal-bacterial consortium under semi-continuous operation

This study aimed at developing an eco-friendly and effective treatment for swine wastewater (SWW) using a designer microalgae-bacteria consortium. A functional algal bacterial consortium was developed with SWW-derived bacteria and Chlorella sorokiniana AK-1. Light intensity (300 µmol/m2/s) and inoculum size (0.15 and 0.2 g/L for microalgae and bacteria) were optimized. Semi-batch operation treating 50 % SWW resulted in a COD, BOD, TN, and TP removal efficiency of 81.1 ± 0.9 %, 97.0 ± 0.7 %, 90.6 ± 1.6 % and 91.3 ± 1.1 %, respectively. A novel two-stage process with an initial bacterial start-up stage followed by microalgal inoculation was applied for attaining stable organic carbon removal, in addition to satisfactory TN and TP removal. Full strength SWW was treated with this strategy with COD, BOD, TN, and TP removal efficiencies of 72.1 %, 94.9 %, 88 %, and 94.6 %, respectively. The biomass consisted of 36 % carbohydrates, indicating a potential feedstock for biochar production. In addition, the effluent met the standards for effluent discharge in Taiwan.

In-situ degradation of Amphotericin B in a microbial electrochemical cell containing wastewater

Antimicrobial resistance raises serious medical implications and is primarily caused by indiscriminate usage and environmental contamination with antimicrobial agents. To prevent microbes from developing resistance against antimicrobial agents, they must be effectively degraded. This is the first study that investigates the degradation of Amphotericin B(AmB) with simultaneous wastewater treatment in a Microbial Peroxide producing cell (MPPC). Two sets of MPPCs (A and B) were used to degrade AmB oxidatively, one with H2O2 and the other with the microbial electro Fenton process in a catholyte containing 0.1% AmB. MPPC A and B had voltage outputs of 0.356 ± 3 V and 0.411 ± 2 V, producing 26 ± 0.04 mM and 44 ± 0.8 mM of H2O2 respectively. The structural changes of treated samples were analyzed using Fourier Transformed Infrared Spectroscopy, which revealed the disappearance of major characteristic bands such as the NH band (1556 cm−1), the CH band Polyene ring (3358 cm−1), and others, implying the disruption of multiple double bonds in polyene, resulting in the structure's lactone ring breakdown. Liquid chromatography quadrupole time-of-flight revealed the changes in retention time and peak area of treated samples in comparison to native AmB which also confirmed its structural changes. Such structural disruption induced the drug to lose its antifungal action since no zones of inhibition were detected in an antimicrobial susceptibility test against Candida albicans. The degradation of 57.05% and 69.83% of AmB by H2O2 and the Fenton process was also correlated with a reduction in COD. Simultaneously the anodic wastewater treatment in both the MPPCs had COD removal efficiency of 78% and 82% and the BOD removal efficiency was 75.38% and 90% respectively. The MPPC system's process conditions and reactor design could be optimized further to enhance antimicrobial degradation and wastewater treatment. This research offers a sustainable and efficient method for expediting antimicrobial degradation while simultaneously treating wastewater.

Emprego de quitosana na remoção de poluentes em efluentes de processamento de pescado

ABSTRACT The significant growth of the industrial sector in recent decades has led to an increase in the volume of waste, which if not properly destined, could cause serious environmental problems. In the context of aquaculture, liquid effluents with a high organic content are generated in large quantities in the fish processing industries, and if their disposal is carried out improperly, serious damage to the environment is caused. The general objective of this study is to evaluate: the efficiency of removal of COD and BOD, in addition to the influence on pH; alkalinity; chlorides; ammonia; nitrite; nitrate; phosphate; turbidity; total, fixed and volatile solids, from the effluent of fish processing treated by coagulation and sedimentation using the natural chitosan coagulant. pH 5.5 followed by pH 6 showed better results for the use of chitosan coagulant in the process of treatment by effluent coagulation of fish processing industry. Chitosan does not act on the parameters TVS, alkalinity, chlorides, ammonia, nitrite, nitrate, and phosphate, regardless of the dosage used. However, it acts on BOD, COD, TS, TFS and turbidity. Thus, the best dosage of chitosan is 0.25 g L-1 in optimized activity at pH of 5.5.

PHYSICO-CHEMICAL ANALYSIS OF TEXTILE EFFLUENT COLLECTED FROM TIRUPPUR BEFORE AND AFTER TREATMENT WITH CRAB (PORTUNUS SANGUINOLENTUS) SHELL CHITOSAN

Textile industries are one of the main sources of wastewater containing high amounts of colour, pH,BOD, COD, DO, TDS, TSS, alkalinity, chloride, phosphate, hardness, chemicals and heavy metals.They contaminate the water bodies and its ecosystem. In the present investigation, textilewastewater was collected from the discharge tank of a Tiruppur textile industry to investigateeleven physico-chemical parameters such as colour, total solids, TDS BOD, COD, Total alkalinity,Total hardness, chlorides, sodium, sulphates and iron. Chitosan extracted from crab shell is selectedas an absorbent to reduce most of the aforesaid parameters present from the textile industrial wastewater. The percentage removal of colour, total solids, TDS BOD, COD, total alkalinity, totalhardness, chlorides, sodium, sulphates and iron were 32.61 mg/l, 90.97 mg/l, 91.81 mg/l, 61.72mg/l, 55.66 mg/l, 91.57 mg/l, 45.90 mg/l, 96.76 mg/l, 66.73 mg/l, 80.77 mg/l and 94.79 mg/l respectively.

Evaluating the performance of sequential batch reactor (SBR & ASBR) wastewater treatment plants, case study

The study aims to assess the operation efficiency of sequencing batch reactor (SBR) and advanced sequencing batch reactor (ASBR) wastewater treatment plants (WWTPs) in Egypt. After auditing more than 24 SBR and ASBR plants, four plants Al-Maamora [MAAM], Al-Negeela [NEGL], Khorshed No. 1 [KOR#1], Khorshed No. 2 [KOR#2] were selected for the current study according to its virtuous performance, good construction conditions and regulatory workflow. COD, BOD and TSS were measured in the influent and effluent samples according to APHA standard methods. Influent quantities and treatment power consumption were monthly recorded. The power consumed for removing a kilogram of BOD and/or treating a cubic meter of wastewater was taken as a comparative indicator among the included WWTPs and between SBR and ASBR technologies. The monthly average inflows were 427058, 189581, 1019876, and 144937 m3/month for MAAM, KOR#1, KOR#2, and NGEL and the monthly power consumption were 56553, 69763, 178,778 and 49545 kW/month respectively. The average removal percentage of the plants reached 92, 91.75, 92.5% for BOD, COD, and TSS respectively, the effluent concentrations of the intended parameters has met the regulatory standard. The average power consumption for removal of a kilogram BOD by SBR and ASBR was 0.932 and 1.58 kWh respectively. SBR and ASBR plants consumed average of 0.245 and 0.296 kWh to treat one cubic meter of wastewater complying with the Egyptian standard for discharge into the drainage canals as a reference values. The study concluded considering the ASBR technology for building new WWTPs or extending current plants, especially for the crowded cities.

Studying the Effects of Organic and Hydraulic Shock Loads on the Membrane Bioreactor (MBR) By Using GPS-X Mathematical Model

Membrane-based systems (MBR) used in wastewater treatment have many advantages over conventional activated sludge processes. They have proven to be very effective in removing organic and inorganic contaminants as well as biological entities from water. The objective of this work is to propose an optimal operation of the bioreactor after having detailed in the relationships between the nature of the sludge, its conditions is obtaining the performance of the membrane using a simulation software (GPS-X). The effects of organic and hydraulic shock loads on the MBR system were also studied. The GPS-X simulation program was used in this study to simulate the membrane bioreactor setup. The BOD removal system we used was 78%. In addition, the MBR system has a significant capacity due to the hydraulic shock load of the operation and the process efficiency for the MBR installation due to this shock load based on BOD removal was reduced up to 65%. The MBR system has a good ability to handle the organic shock loads of the operation with no significant loss in treatment efficiency. The treatment efficiency of the MBR system, due to organic shock loads based on BOD removal, decreased slightly to 80%, however, it is shown how their properties determine the extent of sludge fouling in the membrane. Based on these results, operational conditions favoring a reduction of fouling are proposed.

Waste Water Treatment Performance of Two Vertical Flow Constructed Wetlands for Agricultural Reuse in Jordan: Enhancing Nitrogen Removal

This study demonstrates the treatment performance of two vertical flow constructed wetlands (VFCWs) for decentralized wastewater treatment plants in Jordan, for reuse purposes to meet the WHO regulations for reuse in agriculture and the Jordanian standards (JS 893/2006). The first system is a recirculating VFCW that has shown high removal efficiency of COD, TSS, and CBOD5 over the study period, conforming to the JS (Category A). Whereas, the Total Nitrogen (TN) and Nitrate (NO3-) removal were limited (55 and 44 mg/L) over the baseline monitoring, conforming to the JS Category-B (TN: 70 mg/L and NO3-N: 45 mg/L). Therefore, the system was modified by converting the recirculation tank into attach growth tank (using electric conduit pipes as plastic media). TN concentration reduced effectively of 40 mg/L, conforming to the JS category-A (TN: 45 mg/L), whereas, NO3–N concentration reduced to 37 mg/L, conforming to the JS Category-B (TN: 45 mg/L). Over the study period, E. coli reduction were constant, 2 log10 reduction, conforming to the JS category C (more than 1000 MPN/100 mL). The second system is two-stage VFCW that has shown high removal efficiency of COD, TSS, and BOD5, conforming to the JS Category-A over the study period. But, TN and NO3–N concentrations were limited (55 and 44 mg/L), conforming to the JS Category-B, due to insufficiency of carbon source to promote denitrification (high BOD5 removal by first filter). Thus, the two-stage VFCW was modified with raw wastewater step-feeding application to the intermediate pump shaft before the second stage filter. The results of operational modification showed a small significant improvement in TN removal (p = 0.005); TN and NO3–N concentrations were reduced to 52 and 50 mg/L, respectively; conforming to the JS Category-B. Higher E. coli removal was observed in the two-stage system than the recirculating system, with an overall average removal of 4.5 log10 units, conforming to the JS category B (less than 2.0 log10 units). While, E. coli reduction influenced negatively by step-feeding modification, conforming to the JS category C

The Development of Polymeric Composite Membrane Containing Plant Waste Derived Activated Carbon and TiO2 for Raw Petroleum Refinery Wastewater Treatment

Petroleum industry results in a huge amount of harmful oily wastewater that must be properly treated. The fabricated composite membrane comprising polyvinylidene fluoride (PVDF), cassava peel-derived activated carbon (AC), and TiO2 was then developed for treating raw petroleum refinery wastewater containing high loading of organic and inorganic pollutants. This study applied different ratios of AC/TiO2 by 0, 1, 2, and 3% in the membrane fabrication solution to study the effect of composite ratio on the quality of permeate, fouling rate, and membrane tensile strength. The experimental work found that the ratio of AC/TiO2 by 3% in the composite membrane outperformed the other ratios. The additives addition by 3% could achieve more than 40, 71, 40, and 67.5% of COD, oil, BOD5, and phenol removal efficiency, respectively. It also reached a lower flux decline by 25% within 250 min of filtration time. Hermia’s model was then applied to study the fouling mechanism occurring during membrane operation. Additionally, it was indicated that membrane tensile strength was also influenced by composite ratio, where higher PVDF amount resulted in higher membrane tensile strength. Overall, this study concluded that composite membrane could be a reliable alternative for treating raw industrial wastewater to existing wastewater treatment technologies. Further research related to the composite membrane integration system with other treatment techniques can then be conducted to lengthen membrane lifespan and improve the permeate quality.

Investigation on the Treatment of Slaughterhouse Wastewater in a Sequential Batch Reactor

In the present study, the treatment of slaughterhouse wastewater was carried out in a sequential batch reactor. A lab-scale column type reactor was fabricated with Perspex material having dimensions of 10 cm diameter, 100 cm height, and an effective volume of 7 liters provided with ports at different levels. The reactor performance was evaluated in terms of COD, BOD, TSS, TKN, and phosphorus removal. The reactor was operated for 432 days; the effectiveness of the reactor is the temperature of wastewater in the reactor. The removal efficiencies of COD and BOD were84% and 80% in the reactor. The maximum TSS removal was around 87% and TKN’s maximum removal efficiency was 61% in aerobic treatment. Phosphorus maximum removal efficiency was around 68%, in the meantime pH and alkalinity were also monitored, and no change in the pH was reported throughout the experiment. On the other hand, an aerobic SBR is also operated using wastewater after the DAF unit. In the same manner, the reactor was operated with initially diluted wastewater (05 times) and kept HRT 8 h. The reactor performance was studied in terms of COD, BOD, TSS, TKN, and phosphorus. The maximum removal efficiencies of COD and BOD were 80% and 81% respectively. The maximum removal efficiencies of TSS, TKN, and Phosphorus were 73%, 81%, and 69% respectively. It is concluded that the removal efficiency of COD was better in the anaerobic process as compared with the aerobic process in addition the generation of methane gas during the degradation of organic matter can be used for operating the aerobic unit by making some necessary arrangements. Besides this, it is also concluded that the removal efficiency of TKN was better in the aerobic process as compared with the anaerobic process. There was a buildup of VSS from 4500 mg.L-1 to 6500 mg.L-1 in the study.

Performance of Porous Substrates for Domestic Wastewater Treatment under Prolonged Hydraulic Retention Time

Physicochemical characteristics of porous substrates (longan biochar, corn biochar, and pumice) including specific surface area (SSA), pore volume (Vp), and cation exchange capacity (CEC) were determined. Longan biochar had the highest SSA, Vp, and CEC, followed by corn biochar and pumice. Then, columns filled with each of these 3 substrates together with gravel as a control treatment, were evaluated to compare wastewater treatment efficiency under different hydraulic retention times (HRTs). Each system had been acclimatized with wastewater for 8 weeks. Then, influent and effluent were analyzed at 1, 3, 5, and 7 day intervals. Water analysis revealed that biochar-based systems showed higher dissolved oxygen (DO) development and greater removal of biochemical oxygen demand (BOD5), total suspended solids (TSS), ammonium (NH4-N), total Kjeldahl nitrogen (TKN), and nitrate (NO3-N) than pumice and gravel-based systems. Prolongation of HRT significantly increased NO3-N removal and slightly increased BOD5 and TSS removal. Both BOD5 and TSS removal in biochar-based systems after 1 day HRT was about 93–94% while they significantly increased with HRT extension to a high of 97–98%. Furthermore, NO3-N removal in biochar-based systems increased from 47–48% after 1 day HRT to 80% after 5–7 days HRT. In addition, NH4-N and TKN removal was influenced by both substrate and HRT with significant interaction between these two factors. Longan biochar-based systems, in particular eliminated almost 90% of both NH4-N and TKN and the removal efficiency improved significantly after HRT was extended. Meanwhile, both NH4-N and TKN removal were only 20–30% in the gravel-based systems and 50-60% in pumice-based system. The study suggests that longan biochar is the most effective substrate. Longer HRTs were also found to increase the efficiency of removing organic matter and nitrogen.

Performance evaluation of vertical constructed wetland units with hydraulic retention time as a variable operating factor

The current research intends to assess the impact of shorter hydraulic retention time (HRTs) and different sized filter material on the pollutant removal performance of two pilot-scale vertical sub-surface flow constructed wetlands (VSSF CW) to treat dairy wastewater. Two CWs (CW-1 & CW-2) were filled with 10 and 20 mm gravels, respectively, planted with Arundo donax, and operated at three different HRTs for treating dairy farm wastewater viz. 6, 12, and 24 h. Over three months, the effluent was tested for TSS, BOD5, TP, and NH4–N removal using standard procedures at regular intervals. Average concentrations of TSS, BOD5, TP, and NH4–N at the final outlets CW-1 and CW-2 were recorded in the range of; TSS: 44.7–118.7 mg L−1, BOD5: 8.1–33.9 mg L−1, TP: 13.7–22.2 mg L−1and NH4–N: 9.1–11.4 mg L−1, respectively. The highest removal of TSS (81.2%), BOD5 (90.2%), TP (65.1%), and NH4–N (82.5%) from wastewater was seen after a 12 h HRT, whereas maximum DO rise (579.0%) was reported after a 6 h HRT in 20 mm gravel-filled CW units. Short HRTs of 6, 12, and 24 h were found to be effective in removing all pollutants from wastewater and maintaining a constant treatment throughout the evaluation period. Results suggest that VSSF CW systems can be operated efficiently under short HRTs while still effectively removing contaminants from dairy wastewater.

Rhizopus oryzae fermentation wastewater nutrient removal coupling protein fodder production by employing Chlorella pyrenoidosa

The scenario was to investigate feasibilities of employing Chlorella pyrenoidosa for Rhizopus oryzae fermentation wastewater nutrient removal coupling protein fodder production. Results stated that TN, TP, NH3-N, COD, BOD removal reached 99.79%, 94.70%, 98.80%, 97.60%, 99.60% to acquire discharge permit under fed-batch manipulation, whilst the peaked protein yield (19.94 g/L) was 6.04-fold more than batch manipulation. Rhizopus oryzae fermentation wastewater feeding C. pyrenoidosa was praised as high-quality protein not only with 26.78% essential amino acids and essential amino acids/nonessential amino acids value of 0.84 but also pathogenic bacteria and heavy metal loads complying with fodder standards. In vitro digestibility of dry matter, protein, lipid, and starch achieving 80.07%, 92.13%, 95.93%, 91.9% and bioavailability of polypeptides, triglycerides, free fatty acids, and oligosaccharides displaying 98.67%, 87.12%, 93.86%, 30.21%, which were roughly-equivalent to corn/soybean fodder. The findings formed exemplifications in utilizing other microalgal systems for wastewater nutrient removal coupling chemicals production.

Influence of the number of levels and system age on greywater treatment in a green wall

The use of green walls for greywater treatment represents a great opportunity to reduce potable water consumption and achieve multiple benefits. This study aims to analyse the efficiency of a pilot scale open-air green wall and evaluate its durability over time. The green wall consists of two modular panels (P1 set up in 2020, and P2 in 2018), each including nine pots organised in three independent columns. Coconut coir (80%) and perlite (20%) were used as filter media for three ornamental plant species (Carex morrowi, Hedera helix, Lonicera nitida). Each column was individually fed in batch mode with 24 Lday−1 (hydraulic loading rate - HLR 740.8 Lm−2 day−1) of greywater from January to March 2021. 190 water samples were analysed for 13 physical-chemical parameters. Both panels exhibited very good removal efficiencies for TSS (P1: 97.4 ± 4.6%, P2: 89.1 ± 13.8%), BOD5 (P1: 98.8 ± 2.4%, P2: 94.5 ± 9.2%), COD (P1: 78.5 ± 5.2%, P2: 80.1 ± 4.2%), TN (P1: 49.2 ± 30.4%, P2: 48.0 ± 23.31%), MBAS (P1: 92.7 ± 3.8%, P2: 75.3 ± 8.0%). P1 reached satisfying pollutants removal after two levels, while P2 showed higher variability and frequent clogging phenomena, needing three levels (e.g., cumulative BOD5 removal along the three levels in P1: 45.2 ± 36.2% | 86.5 ± 14.8% | 98.8 ± 2.4%; in P2: 16.5 ± 20.8% | 51.8 ± 32.3% | 94.5 ± 9.2%). This highlighted that the third level of P2 was necessary to guarantee good performances after over 2 years of operation. This study confirmed that green walls have high potential in greywater treatment also in challenging conditions (i.e. winter climate, high HLR and operating times), opening to further studies devoted to extending their lifetime.

Activated sludge microbial communities and hydrolytic potential in a full-scale SBR system treating landfill leachate

Landfill leachate, due to its recalcitrant nature and toxicity, poses a serious environmental threat, which requires the implementation of effective treatment processes. In this work, a full-scale treatment system consisting of two Sequencing Batch Reactors (SBRs) was used for the processing of landfill leachate of intermediate to mature age (BOD/COD ratio of 0.16). Biosystem operation resulted in BOD5, COD and TKN removal efficiencies of 81%, 39% and 76%, respectively, whereas the low residual NO3 --N concentration in the effluent (4.01 ± 0.10 mg/L) was indicative of the efficient denitrification process. Assessment of hydrolytic potential of activated sludge revealed high endocellular and extracellular lipase activities, which reached values up to 206 and 141 U/g protein respectively, possibly as the consequence of plastics degradation during maturation process. Implementation of Illumina sequencing indicated the predominance of Alphaproteobacteria, accompanied by members of Bacteroidetes, Betaproteobacteria and Chloroflexi. Paracoccus was the predominant genus identified, followed by representatives of the genera Bellilinea, Flavobacterium, Thauera and Truepera. Nitrosomonas was the major ammonia-oxidizing bacterium (AOB), while nitrite oxidation was mainly achieved by the uncultured nitrite-oxidizing bacterium (NOB) Candidatus Nitrotoga.

Insight into a novel post-anoxic integrated biofilm process for wastewater treatment and reclamation

A novel pilot scale post-anoxic integrated biofilm activated sludge system of capacity 50 m3/d, was used to treat municipal wastewater. Treatment process comprised of three biological reactors which includes aerobic tank with PVA-gel beads followed by anoxic tank and aerobic tank. The plant was operated at HRT of 6 h, with an average SRT of 10 days. Long term performance evaluation of the combined system showed that BOD, COD, TSS and TN removal efficiencies were 91, 90, 93 and 84 % respectively. In PVA-gel tank, significant removal of NH4-N and NO3-N occurred due to nitrification and denitrification process (85 %) in the system. It was observed that the efficiency of SND process varied with temperature and COD/N ratio variation. Maximum TN removal of 80–90 % was noted at temperature range (10–25 °C) and COD/N ratio was 10–22 kg COD/kg of TN. Removal of organic matter and NH4-N in first media tank was dependent on temperature and the loading rates. Significant removal was observed at loading rate 16 kg SCOD/m3 gel/d and 2.4 kg NH4+/m3 gel/d, respectively. The pathogens removal efficacy of the system was higher (>90 %). Bacterial community analysis of immobilized biomass (PVA-gel beads) revealed the presence of Alpha proteobacteria genera, Actinobacterium, Nitrosococcus, Pseudomonas, Fusobacterium and Nitrosomanas species responsible for high carbon and nitrogen removal efficiency of the system. The study concluded that BOD, TSS and TN (<10 mg/L) values were below Indian effluent discharge standards. Average cost to treat 1 m3 of wastewater was calculated as INR 36.05 (electricity input cost: INR 9.6). Overall, post-anoxic integrated biofilm process achieved significant removal of nitrogen and carbon.

High-efficiency contaminant removal from hospital wastewater by integrated electrocoagulation-membrane process

In this work, high removal of contaminants in hospital wastewater has been achieved using an integration of electrocoagulation (EC) with ultrafiltration (UF) and reverse osmosis (RO). In EC system, Al electrodes were arranged in a monopolar-parallel and bipolar configuration. There are two parameters studied in the EC system, i.e., the configuration of electrodes (2A-2C-2B and 4A-2C-2B) and current densities. The EC-UF system with a configuration of 4A-2 C-2B and a current density of 88.5 A.m−2 resulted in high removal of TSS, TDS, BOD, and COD by 95.12 %, 97.53 %, 95.18 %, and 97.88 %, respectively. The effluent quality of the EC-UF was improved by substituting UF with RO membrane. The TSS, TDS, BOD, and COD removal were enhanced to 97.64 %, 99.85 %, 97.88 %, and 98.38 %, respectively. The permeate flux decline in UF membrane system was 47.83 % during 60 min of filtration time due to cake layer fouling on the membrane surface, while in the RO membrane system was 29.49 %. Since the EC-UF and EC-RO showed high efficiency in contaminants removal, these configurations could be used as clean technology to produce clean water for water reuse purposes. At a wastewater capacity of 5 m3.day−1, the operating cost for the EC-UF system was 3.92 US$.m−3, while the EC-RO system was 4.02 US$.m−3. The increase of wastewater capacity to 50 m3.day−1 reduced the operating cost to 0.89 US$.m−3 for the EC-UF system and 0.93 US$.m−3 for the EC-RO system.

Abattoir Wastewater Treatment Plants in India: Understanding and Performance Evaluation

Slaughterhouse plants, especially meat and poultry products (MPPs), generate significant quantities of wastewater during the slaughtering process and the cleaning of machinery. The handling and final disposal of wastewater from the slaughterhouse is a public and environmental health issue due to its pollution potential. The monitoring of three full-scale buffalo meat-based abattoir effluent treatment plants (ETPs) to remove organic matter and nutrients was conducted at three separate sites in India. Rotary and static screens, an equalization tank, a dissolved air flotation (DAF) system, aeration tanks, and clarifiers were the component unit operations/processes of the wastewater treatment systems. All the treatment plants were operating at an average flow rate of 254 m3/d Meem Agro (designed capacity 500 m3/d); 427 m3/d Al Noor (designed capacity 500 m3/d), and 353 m3/d International Agro Foods (IAF) plant (designed capacity 750 m3/d) for the treatment of slaughterhouse wastewater. The Al Noor and Meem Agro’s ETP consisted of a DAF unit working at the surface-loading rates of 5.7 and 1.48 m3/m2 h, respectively, applied during the analysis to the DAF system, resulting in 46.5 and 56.8% efficiencies of O&amp;amp;G and SS removal. The ETP of Al Noor and Meem Agro and IAF was loaded at an organic loading rate of 276 kg COD/day, 746 kg COD/day, and 629 kg COD/day, respectively. Performance of ETPs showed that the efficiency of total COD, total BOD, and TSS removal was 97, 98, and 99%; 94, 94, and 93%, and 95, 98, and 99% for Al Noor, Meem Agro, and IAF plants, respectively. The treatment plants’ efficiencies in all three plants for the removal of organic matter surpassed the effluent discharge level (as per Indian standards). Still, it is concluded that the ETPs need to be upgraded by incorporating the advanced wastewater treatment methods for the removal of nutrient concentration from treated effluents.

Real and Synthetic Greywater Treatment by a Combined Process of Ozonation, Granular Activated Carbon, and Ultrafiltration

Background: The water crisis in different parts of the world forces people to manage water resources. Greywater can be used to reduce water stress. The annual rainfall average in Iran is hardly one-third of the world. In this study, the treatment of synthetic greywater at low, medium, and high organic load and real greywater (RGW) by a combined process of ozonation/granular activated carbon (GAC)/ultrafiltration (UF) have been investigated. Objectives: This study aimed to find a greywater treatment method that is effective, new, environment-friendly, and cost-effective. Methods: Chemicals and commercial compounds were used to prepare synthetic greywater, and the research pilot was developed. After several preparation steps, the GAC was transferred to a GAC reactor. A continuous flow of synthetic greywater entered the treatment system with low: 6.1, medium: 12.2, and high: 18.3 gCOD/L.d organic loading rates for 6 months. Next, the RGW samples from a residential complex in Shiraz, Iran, entered the treatment system for two weeks. After chemical analysis, an analysis of variance was carried out to compare the removal efficiency of parameters: [chemical oxygen demand (COD), five-day biochemical oxygen demand (BOD5), turbidity, and linear alkylbenzene sulfonates (LAS)] at various organic loads (low, medium, and high) of synthetic greywater and RGW. Results: We found the average COD removal in low, medium, and high organic loads of synthetic greywater and RGW as approximately 79.3%, 86.1%, 77.3%, and 97.3%, respectively. Moreover, the average BOD5 removal in the mentioned groups was about 69.6%, 48.9%, 42.7%, and 86.8%, respectively. The average of turbidity removal was 95.6%, 98.3%, 97.4%, and 97.9%, and average LAS removal was 90.1%, 88.9%, 88.3%, and 91.9%, respectively. Conclusions: This treatment method is remarkable for real and synthetic greywater treatment. It can effectively remove COD, BOD5, turbidity, and LAS. In addition, it is a relatively low-cost and environment-friendly system. Therefore, it can be recommended as a greywater treatment method, especially in countries with inadequate water supplies, such as Iran.