Potential Treatment Process Research Articles

Ozone disinfection of waterborne pathogens: A review of mechanisms, applications, and challenges.

Water serves as a critical vector for the transmission of pathogenic microorganisms, playing a pivotal role in the emergence and propagation of numerous diseases. Ozone (O3) disinfection technology offers promising potential for mitigating the spread of these pathogens in aquatic environments. However, previous studies have only focused on the inactivated effect of O3 on a single pathogenic microorganism, lacking a comprehensive comparative analysis of various influencing factors and different types of pathogens, while the cost-effectiveness of O3 technology has not been mentioned. This review synthesized the migration characteristics of various pathogenic microorganisms in water bodies and examined the properties, mechanisms, and influencing factors of O3 inactivation. It evaluated the efficacy of O3 against diverse pathogens, namely bacteria, viruses, protozoa, and fungi, and provided a comparative analysis of their sensitivities to O3. The formation and impact of harmful disinfection by-products (DBPs) during the O3 inactivation process were assessed, alongside an analysis of the cost-effectiveness of this method. Additionally, potential synergistic treatment processes involving O3 were proposed. Based on these findings, recommendations were made for optimizing the utilization of O3 in water inactivation in order to formulate better inactivation strategies in the post-pandemic eras.

Efficient rhodamine B dye photocatalytic degradation in aqueous media using novel ZnO nanomaterials co-doped with Ce and Dy

Water pollution caused by dyes and industrial wastewater poses a significant threat to ecosystems. The purification of such pollutants presents a major challenge. Photocatalysis based on semiconductor materials is a potential wastewater treatment process due to its safety and cost-effectiveness. In the present work, Zn1-2xCexDyxO (x = 0.01–0.05) semiconductors were prepared by the sol-gel auto-ignition method. The samples are denoted CDZO1, CDZO3, and CDZO5 for x = 0.01–0.05, respectively. The X-ray diffraction and Raman spectroscopy results revealed the formation of ZnO hexagonal phase wurtzite structure for all synthesized compositions. Different structural properties were determined. It was found that the lattice parameters and the unit cell volume increased, while the crystallite size diminished as x varied from 0.01 to 0.05. Transmission electron microscopy observations confirmed the formation of nanoparticles with the desired chemical compositions. The specific surface area (SSA) values are found to be 39.95 m2/g, 48.62 m2/g, and 51.36 m2/g for CDZO1, CDZO5, and CDZO5 samples, respectively. The reflectance spectra were recorded to examine the optical properties of the different nanoparticles. The values of the optical band gap were 3.221, 3.225, and 3.239 eV for CDZO1, CDZO3, and CDZO5 samples, respectively. In addition, the photocatalytic performance towards RhB dye degradation for the different samples was assessed. It was established that the CDZO3 sample with a moderate SSA value exhibited the superior photocatalytic performance among the other as-prepared samples wherein the percentage of degradation efficiency, and kinetic constant rate attained their maximum values of 98.22 % and 0.0521 min−1, respectively within 75 min. As per the obtained findings, it is evident that the Zn1-2xCexDyxO photocatalyst has prominent potential for use in the degradation of dyes and offers a useful route for impeding the recombination of electron-hole pairs of zinc oxide material.

Co-, Ni-, and Cu-Doped Fe-Based Catalysts for the Microwave-Assisted Catalytic Pyrolysis of Polyethylene.

Environmental issues caused by waste polyethylene are becoming increasingly severe. Among potential treatment processes, microwave-assisted catalytic pyrolysis is promising for converting waste plastics into valuable products owing to its energy efficiency and environmental sustainability. Herein, a modified citric acid combustion method was used to prepare a series of metal oxide catalysts with loose porous structures. The prepared Fe-based catalysts doped with Co, Ni, or Cu were employed in the microwave-assisted catalytic pyrolysis of polyethylene. The bimetallic Co1Fe1Ox catalyst exhibited the best performance, yielding hydrogen at a rate of 60.7 mmol/gplastic. Further variation in the Co : Fe ratio revealed that the Co1Fe9Ox catalyst achieved the highest hydrogen production efficiency (63.64 mmol/gplastic). Similar oil-phase products were obtained over the various catalysts, as revealed by infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. Furthermore, scanning electron microscopy (SEM) identified carbon nanotubes as the major solid product of pyrolysis, which were attached to the catalyst surface. Finally, a combination of thermogravimetric analysis, SEM, and energy-dispersive X-ray spectroscopy indicated that the reduction in catalytic activity following recycling was caused by the accumulation of carbonaceous products on the catalyst surface. Overall, Co1Fe9Ox catalysts were favorable for obtaining H2 and carbon nanotubes by the microwave-assisted pyrolysis of polyethylene.

Plasmonic titanium nitride-based membranes for solar-driven domestic wastewater distillation treatment

Membrane separation processes have emerged as efficient wastewater treatment technologies due to their reduced footprint, sustainability, cost-effectiveness, ease of operation, high filtration selectivity, and compliance with end-user requirements. Especially solar-driven membrane distillation, known for its low energy requirements and high pollutant rejection rates, has gained prominence as a potential wastewater treatment process that does not need external thermal energy input for water treatment. Herein, we demonstrate plasmonic titanium nitride nanoparticle-incorporated polymeric membranes for the solar-driven membrane distillation of domestic laundry wastewater, specifically focusing on SDBS (sodium dodecylbenzene sulfonate) surfactant removal. Under solar illumination, the plasmonic element within the polymeric matrix enables a localized heating effect driven by photothermal conversion in the proximity of the surface of distillation membranes, thereby producing a vapor pressure enough for water distillation across the hydrophobic membranes. The fabricated photothermal mixed matrix membranes showed incremental distillation flux and derived energy efficiency with the loading of titanium nitride nanoparticles under light illumination, reaching up to 0.47 kg/m2h and 29.79 %, respectively. The rejection rate against SDBS achieved up to 99 %. We also verified that its distinctive surface photothermal heating effect is associated with enhanced plasmonic absorption, surface thermal conductivity, and improved interfacial heat transfer of the membranes in the presence of plasmonic elements. The photothermal membranes proved that the permeate produced by photothermal distillation of real laundry wastewater fulfilled all required parameters for safe use as irrigation water, demonstrating its practical feasibility and viability of solar-driven distillation for domestic wastewater treatment and reuse.

Local laser heat treatment of AlSi10Mg as-built parts produced by Laser Powder Bed Fusion

Today, complex structural components for lightweight applications are frequently manufactured by laser powder bed fusion (PBF-LB), often using aluminum alloys such as AlSi10Mg. However, the application of cyclic load cases can be challenging as PBF-LB produced AlSi10Mg parts typically have low ductility and corresponding brittle failure behavior in the as-built condition.Therefore, this paper presents investigations on the feasibility of a laser heat treatment of PBF-LB produced AlSi10Mg parts to locally increase the ductility and decrease the hardness in critical areas. Potential heat treatment process parameters were derived theoretically based on the temperature fields in the material calculated assuming three-dimensional heat conduction and a moving heat source. PBF-LB produced specimens were then laser heat treated at varying laser power and scan speed. Hardness measurements on metallographic cross sections showed hardness reductions of over 35 % without inducing hydrogen pore growth.

An online acceptance, commitment, and self-compassion based treatment to decrease psychological distress in people with type 2 diabetes: A feasibility randomised-controlled trial

Background and purposeThis study explored the feasibility and acceptability of conducting a larger trial of a self-guided, online self-compassion and acceptance and commitment therapy (ACT) focused treatment among people with type 2 diabetes (T2D) to decrease psychological distress. Materials and methodsThis study was a two-arm, parallel, feasibility randomised controlled trial with nested qualitative methods. UK adults with T2D were randomly (1:1) allocated to a five-week online self-compassion and ACT treatment or waitlist control. Information regarding recruitment, trial retention, and treatment completion was collected, and post-treatment semi-structured interviews were conducted to assess feasibility and acceptability. Self-report measures of psychological distress (depression, anxiety, diabetes distress) and potential treatment processes (self-compassion and psychological flexibility) were completed as secondary feasibility outcomes. ResultsFifty-five (60.44 %) out of 91 people who accessed the study link were eligible to participate. Of these, 33 eligible participants (60 %) were randomly assigned to treatment (n = 19) or control arms (waitlist; n = 14). While treatment completion was 47.37 %, trial retention rates were 39.39 % (5-week follow-up) and 21.2 % (9-week follow-up). Secondary feasibility outcomes of treatment effect estimates are difficult to interpret in light of low treatment completion and trial retention rates. ConclusionA larger trial of the self-guided, online self-compassion treatment to decrease psychological distress in people with T2D may be beneficial, but it has limited feasibility in its current form. Further efforts are needed to improve treatment acceptability of online self-compassion and ACT focused treatment and trial procedures.

Recent advances in simultaneous nitrification and denitrification for nitrogen and micropollutant removal: a review.

Simultaneous Nitrification and Denitrification (SND) is a promising process for biological nitrogen removal. Compared to conventional nitrogen removal processes, SND is cost-effective due to the decreased structural footprint and low oxygen and energy requirements. This critical review summarizes the current knowledge on SND related to fundamentals, mechanisms, and influence factors. The creation of stable aerobic and anoxic conditions within the flocs, as well as the optimization of dissolved oxygen (DO), are the most significant challenges in SND. Innovative reactor configurations coupled with diversified microbial communities have achieved significant carbon and nitrogen reduction from wastewater. In addition, the review also presents the recent advances in SND for removing micropollutants. The micropollutants are exposed to various enzymes due to the microaerobic and diverse redox conditions present in the SND system, which would eventually enhance biotransformation. This review presents SND as a potential biological treatment process for carbon, nitrogen, and micropollutant removal from wastewater.

Experimental study on alkali catalytic gasification of oily sludge in supercritical water with a continuous reactor

Realizing the harmless resource utilization of oily sludge is urgent for petroleum industry and of great significance for environmental management. The treatment of oily sludge was investigated using supercritical water gasification (SCWG) with a continuous fluidized bed reactor. The effect of operating parameters on gasification efficiency and gas yield without catalyst was tested, and then the influences of catalyst type (K2CO3 and Na2CO3) and concentrations (1–8 wt%) were systematically studied. The results indicated that a medium mass flow ratio and low feedstock concentration were beneficial for gas production. Alkali catalyst improved carbon gasification efficiency (CE) prominently, and Na2CO3 showed better performance due to its better stability. A maximum CE of 95.87% was achieved when 5 wt% Na2CO3 was added at 650 °C, 23 MPa with 5 wt% oily sludge concentration. Besides, according to XRD patterns of solid residues, Na2CO3 was more stable than K2CO3 during SCWG. SEM-EDX results also revealed that more K was migrated into solid residues than Na. The analysis of pore structure demonstrated that alkali catalyst promoted the evolution of pore structure, resulting in higher specific surface areas and total pore volumes. Na2CO3 has a more substantial destructive effect on solid matrix, causing the matrix structure to collapse and inhibiting pore structure development. The FTIR spectra of solid products exhibited a lower content of carbohydrates and aromatic structures than the initial oily sludge. NH4–N results demonstrated that SCWG was a potential green treatment process for oily sludge. This work can not only give an insight into the reaction mechanism of alkali catalytic gasification of oily sludge, but also help to guide the optimal design of reactor and the regulation of operating parameters.

A State-of-the-Art Review on SARS-CoV-2 Virus Removal Using Different Wastewater Treatment Strategies

In addition to the numerous health effects caused by the COVID-19 pandemic, the scientific community has considered other emerging effects such as water-related impacts worthy of deep investigation. In this regard, the transmission cycles of the SARS-CoV-2 virus from fecal, vomiting, and sputum routes to sewage have led health authorities to diagnose, prevent, and use novel wastewater treatment technologies. Once they enter the gastrointestinal canal of a healthy person, viral particles can infect via the nominal amount of Angiotensin-Converting Enzyme 2 (ACE2) present in alimentary canal epithelial cell surfaces and further infect lung, heart, kidney, and other organs. The current review highlights the detection, status, and fate of SARS-CoV-2 from sewage treatment facilities to water bodies. Besides, it addresses the potential wastewater treatment processes to cope with various viruses, especially SARS-CoV-2. Many processes can manage contaminated wastewater and solid wastes over the long term, including membrane technologies, disinfectants, UV-light and advanced oxidation methods like photocatalysis, ozonation, hydrogen peroxide, nanomaterials, and algae. Future work must focus on implementing the selected actions for the treatment of the wastewater released from the COVID-19 hospitals and self-quarantine centers to better regulate future waves of SARS-CoV-2.

Utilization of brown alga (Sargassum plagiophyllum) as an efficient reinforcement material for application in wheat gluten biocomposites

AbstractIn this work, brown alga (Sargassum plagiophyllum) was utilized as a reinforcement material to produce wheat gluten (WG) biocomposites. The effect of brown alga powder (BP) content and sonication treatments of BP on the properties of the obtained WG biocomposites were characterized. Adding 1 wt% BP to WG increased the tensile strength by 77% compared to neat WG and could delay the degradation process of the WG biocomposites due to the good interaction between BP and the WG matrix. When the time and amplitude of BP sonication was increased, the tensile strength of the obtained WG biocomposites slightly decreased, but still remained higher than the tensile strength of the neat WG. Therefore, this work presents an efficient reinforcement material and a potential treatment process to produce promising alternative biocomposites for the production of environment friendly materials.

Impact of Blackwater Disposal in Erbil City on Municipal Wastewater and Bounded Soil Characteristics with Potential Solutions

<p>Direct discharge of black water (BW) without treatment to the natural environment causes problems for the environment. The present research aimed to examine the impact of direct disposal of BW on the municipal wastewater (MWW) and surrounded soil characteristics in the BW disposal site in Erbil City- Kurdistan Region (KR), Iraq. To check the effect of BW on the boarded MWW and the soil; BW, MWW, BW mixed with MWW (BWMWW), polluted soil, and clean soil samples were collected and analyzed. Samples of BW, MWW, and BWMWW were tested for 32 physical-chemical and biological quality parameters such as pH, turbidity, solids, color, dissolved oxygen, five day biochemical oxygen demand (BOD5), chemical oxygen demand (COD), ammonia, oxidation-reduction potential (ORP), sulphate, oil and grease, phosphate, Most probable number (M.P.N.) of coliform, Thermo tolerant, M.P.N. E.Coli …etc. In contrast, soil samples were tested for 37 parameters, for instance pH, ORP, organic matter (OM), sulfite, Titanium, Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel, Copper, Zinc, Gallium, Arsenic, Rubidium, Strontium, Yttrium, Zirconium, Molybdenum, Silver, Cadmium, Mercury, Lead, Thorium and Uranium. Results revealed that the direct disposal of BW without treatment commonly affected on the MWW and the surrounded soil characteristics. Potential treatment processes and solutions for BW disposal were presented.</p>

A Network Analysis of Clinical Variables in Chronic Pain: A Study from the Swedish Quality Registry for Pain Rehabilitation (SQRP).

Efforts to identify specific variables that impact most on outcomes from interdisciplinary pain rehabilitation are challenged by the complexity of chronic pain. Methods to manage this complexity are needed. The purpose of the study was to determine the network structure entailed in a set of self-reported variables, examine change, and look at potential predictors of outcome, from a network perspective. In this study we apply network analysis to a large sample of people seeking interdisciplinary pain treatment (N = 2,241). Variables analyzed include pain intensity, pain interference, extent of pain, depression, anxiety, insomnia, and psychological variables from cognitive behavioral models of chronic pain. We found that Acceptance, Pain Interference, and Depression were key, "central," variables in the pretreatment network. Interestingly, there were few changes in the overall network configuration following treatment, specifically with respect to which variables appear most central relative to each other. On the other hand, Catastrophizing, Depression, Anxiety, and Pain Interference each became less central over time. Changes in Life Control, Acceptance, and Anxiety were most strongly related to changes in the remainder of the network as a whole. Finally, no network differences were found between treatment responders and non-responders. This study highlights potential future targets for pain treatment. Further application of a network approach to interdisciplinary pain rehabilitation data is recommended. Going forward, it may be better to next do this in a more comprehensive theoretically guided fashion, and ideographically, to detect unique individual differences in potential treatment processes.

Research of wastewater treatment from non-destructive detection by “wet oxidation-biochemical process-intelligence oxidation”

Non-destructive detection with colored-liquid was an effective detection method, which was widely used in non-destructive detection industry. High-concentration of wastewater with COD, color and surfactants would be produced in detection process. Through the biochemical treatment combined with wet oxidation, the COD dose would be reduced from 49200 mg/L to less than 100 mg/L. The color will be degraded from 5000 times to less than 40 times, which will match the requirements for reuse and discharge. Through the molecular distribution and bacteria toxicity test, wet oxidation reduced the inhibition rate of toxicity from 99.99% to 90.88%, which promoted the biochemical treatment performance. The average molecular weight of non-destructive wastewater was reduced obviously from 1486118 to 20376. In the end, the residual chlorine indicator was used to control dose of chlorine less than 3 mg/L to ensure that the color was less than 40 times and residual chlorine was not harmful to environment. The oxidation process was intelligence oxidation. The lab-scale experiment provided potential and available treatment process for non-destructive detection-wastewater.

Bioaugmentation of p‐chloronitrobenzene in bioelectrochemical systems with Pseudomonas fluorescens

AbstractBACKGROUNDp‐Chloronitrobenzene (p‐CNB) is easily accumulated in the environment and subsequently is a threat to humans and the ecosystem. The anaerobic process as an important pathway for p‐CNB degradation has a relatively low degradation rate. This study illustrated that the strain Pseudomonas fluorescens was evaluated as the biocatalyst for bioaugmentation to enhance the p‐CNB removal in bioelectrochemical system (BES).RESULTSWhen the initial p‐CNB concentration was 100 mg L−1, the p‐CNB removal efficiency reached 100% at 12 h in BES with P. fluorescens. All the p‐CNB removal efficiencies in BES were higher than that in anaerobic degradation and electrocatalysis. Meantime, the highest total organic carbon (TOC) removal efficiency was obtained at 89.8% after augmentation with P. fluorescens. During the bioaugmentation, microbial community analysis showed that the main abundance changes were in Pseudomonas, Romboutsia and Macellibacteroides. The cyclic voltammetry (CV) showed BES with bioaugmentation had the highest activity in reducing p‐CNB and hydrogen evolution. Combined with intermediates analysis, bioaugmentation possibly stimulated nitro reduction and hydrodechlorination rate in p‐CNB reduction.CONCLUSIONThese results demonstrate that BES with P. fluorescens bioaugmentation could serve as a potential treatment process for p‐CNB removal. © 2019 Society of Chemical Industry

Fabrication of GO@MIL-101(Fe) for enhanced visible-light photocatalysis degradation of organophosphorus contaminant

Metal–organic frameworks (MOFs) have become one of the most attractive classes of materials due to their versatile features. It is desirable to evaluate the photocatalysis performance of MOFs in aquatic medium. In this study, graphene oxide compositing MIL-101(Fe) (GO@MIL-101(Fe)) was fabricated. Based on this MOF, a light/MOF/H2O2 photocatalysis system was developed to degrade tris(2-chloroethyl) phosphate (TCEP). GO@MIL-101(Fe) has a lower band gap energy (2.17 eV) than MIL-101(Fe) (2.41 eV), suggesting an expansion of visible light absorption from 520 nm to 570 nm. Under 420 nm irradiation, removal of TCEP under the 15%GO@MIL-101(Fe) photocatalysis system followed pseudo-first-order kinetic with a reaction rate constant at 1.64 × 10−3 s-1. Using GO@MIL-101(Fe), a fast activation and electron transfer was achieved due to the high conductibility of GO, resulting in a higher removal efficiency of TCEP (∼95% at 30 min) than using MIL-101(Fe) (∼50%). The basic reaction mechanism involved the excitation of electrons from HOMO (oxygen orbitals in ligands) to LUMO (Fe(II)/Fe(III) in core nodes) induced by visible light irradiation, followed by the electron transport between GO@MIL-101(Fe) and H2O2 to generate OH. GO@MIL-101(Fe) visible-light photocatalysis would be a potential treatment process for organic contaminants.

Concentration and treatment of ceric ammonium nitrate wastewater by integrated electrodialysis-vacuum membrane distillation process

Ceric ammonium nitrate manufacture generated a large number of acidic wastewater, which contained a certain amount of ceric. To treatment this wastewater and recovery the ceric resource and waste acid, an electrodialysis-vacuum membrane distillation (ED-VMD) hybrid system was introduced. To establish a stable and efficient system, a series of membrane materials, performance parameters and solution properties were investigated. It was found that NO3− could be separated from Ce4+ and recovered efficiently in ED system. pH value of Cerium wastewater decreased in the ED process which ensured a stable and reliable operation of the following concentration technology. The high resistance of Ce4+ and high NO3− recovery efficiency in ED anode compartment supplied an opportunity for industry waste acid recycling as well. The VMD process provided more than 99.9% rejection of Ce4+ and concentrated it maximally. Furthermore, membrane cleaning procedures were discussed in order to keep the high efficiency of VMD system. The results implied that vapor condensation inside the pores was the main reason caused membrane fouling and flux decreasing. And the drying procedure was the most efficient cleaning method. This work provided a potential treatment process for rare earth metals wastewater treatment, which decreased the wastewater discharge and recycled the resource in some field.

Wastewater treatment for nutrient removal with Ecuadorian native microalgae

ABSTRACTThe aim of this project was to study the feasibility of utilizing native microalgae for the removal of nitrogen and phosphorus, as a potential secondary wastewater treatment process in Ecuador. Agitation and aeration batch experiments were conducted using synthetic secondary wastewater effluent, to determine nitrogen and phosphorus removal efficiencies by a native Ecuadorian microalgal strain. Experimental results indicated that microalgal cultures could successfully remove nitrogen and phosphorus. and removal efficiencies of 52.6 and 55.6%, and 67.0 and 20.4%, as well as production efficiencies of 87.0 and 93.1% were reported in agitation and aeration photobioreactors, respectively. Aeration was not found to increase the nutrient removal efficiency of . Moreover, in the case of , a negative impact was observed, where removal efficiencies decreased by a factor of 3.3 at higher aeration rates. To the best of our knowledge, this is the first report of the removal of nutrients by native Ecuadorian Chlorella sp., hence the results of this study would indicate that this native microalgal strain could be successfully incorporated in a potential treatment process for nutrient removal in Ecuador.

From fly ash waste slurry to functional adsorbent for valuable rare earth ion separation: An ingenious combination process involving modification, dewatering and grafting

Acid extracting aluminum from fly ash would produce pestilent secondary fly ash slurry with strong acidity, high content of Cl− and residual Al3+ that is difficult to be further used. In order to achieve the zero emission, a potential integrated treatment process for reutilization was proposed in this paper. By intelligent use of residual Al3+ in sludge as catalyst, hydrophobic modification of solid particle was taken with fatty acid via a heterogeneous esterification at normal temperature. Due to the solvophobic force, moisture content of its filter cake was 36.46%, which reduced 11.14% compared with the unmodified one, hydrophobicity scale can achieve 100% with modifier accounting for only 0.8% of solid content and the Cl− concentrations decreased from 20 to 0.102 g/L in wash liquor, thus greatly saving water for washing and energy for drying. Subsequently, based on the appearance of hydrocarbon chains on particle surface, a high-efficiency ultraviolet-induced grafting polymerization was implemented to fabricate density polyacrylic acid decorated fly ash particles from the surface “CH” sites, the resultant composite was proved to efficiently separate valuable rare-earth Gd3+ from wastewater with outstanding adsorption and regeneration performance, hence bringing high added-value utilization for these hazardous waste.

Pilot-scale investigation of sludge reduction in aerobic digestion system with endospore-forming bacteria

A pilot-scale investigation of membrane-based aerobic digestion system dominated by endospore-forming bacteria was evaluated as one of the potential sludge treatment processes (STP). Most of the organic matter in the sludge was removed (90.1%) by the particular bacteria in the STP, which consisted of mixed liquor suspended solid (MLSS) contact reactor (MCR), MLSS oxidation reactor (MOR), and membrane bioreactor (MBR). The sludge was accumulated in the MBR without wasting, and then the effluent in STP was fed into the first step in water resource recovery facility (WRRF). According to the analysis of microbial communities in all reactors, various Bacillus species were present in the STP, mainly due to their intrinsic resistance to the extreme conditions. As the surviving Bacillus species might consume degraded microorganisms for their growth, these endospore-forming bacteria-based STP could be suitable for the sludge reduction when they operated for a long time.

Dissolved air flotation as a potential treatment process to remove Giardia cysts from anaerobically treated sewage

ABSTRACTControlling Giardia cysts in sewage is an essential barrier for public health protection, reducing possible routes of protozoa transmission. The aim of this study was to evaluate the capability of dissolved air flotation (DAF), on a bench scale, to remove Giardia cysts from anaerobic effluent. Moreover, removals of indicator microorganisms and physical variables were also investigated. Flocculation conditions were studied, associating different flocculation times with different mean velocity gradients. DAF treatment achieved mean log removals in the range of 2.52–2.62 for Giardia cysts, depending on the flocculation condition. No statistical differences were observed among the flocculation conditions in terms of cyst removal. Low levels of turbidity and apparent color obtained from the treated effluent may indicate good treatment conditions for the DAF process in cyst removal. Indicator microorganisms were not able to predict the parasitological quality of the wastewater treated by flotation in terms of cyst concentrations. The DAF process provided an effective barrier to control cysts from sewage, which is an important parasite source.