Kind Of Wastewater Research Articles

Feasibility of Biological Elimination of COD, Ammonia-Nitrogen and Total Nitrogen from HTS Molecular Sieves Wastewater Using SBR Processes

The wastewater from hollow titanium silicate (HTS) zeolite consists essentially of high concentrations of COD and salt, and low ammonia-nitrogen concentrations (or high, sometimes). These chemical pollutants are produced in very large quantities during oil refining and are very difficult to manage on site. In addition, they can be very harmful to the environment when released without any treatment. The aim of this study is to evaluate, on the one hand, the feasibility of removing the COD from HTS wastewater using a sequencing batch reactor (SBR) and, on the other hand, to test the combined effect of nitrification and denitrification under different conditions of treatment on the elimination of Total Nitrogen (TN) from HTS wastewater containing a high concentration of ammonia-nitrogen. SBR intermittent domestication tests of sludge have been successfully carried out with wastewater from a municipal treatment plant with a COD removal rate of 87%. Subsequently, HTS wastewater containing high concentrations of COD was treated by this SBR system. After three months of operation, the efficiency of COD elimination fluctuated between 47% and 67%. Therefore this result could serve as a precursor to a possible second COD bioprocessing. The results obtained during nitrification of the same HTS molecular sieves wastewater with low C/N ratio gave, under an operating temperature below 10°C (winter conditions), less than 16% of total nitrogen (TN) removal. When the temperature was increased to 40°C, the TN removal efficiency remained worse. These observations make it possible to affirm that the change in temperature solely had no effect on oxidation of TN. Thereafter, two SBR devices were used for the denitrification process: one containing HTS wastewater, activated sludge and glucose as carbon source, and the other only HTS wastewater and activated sludge. In both cases, the elimination of TN still low even with an increase in the amount of glucose. These situations show that the TN removal was not only depended on type of carbon source. Based on the results of nitrification and denitrification tests, it may turn out that the activated sludge microorganisms’ activities were affected by the HTS molecular sieves wastewater high concentration as well as the salinity (about 3%) of this kind of wastewater.

Microalgae for saline wastewater treatment: a critical review

Saline wastewater contains numerous pollutants such as nutrients, heavy metals, micropollutants, and organic pollutants. This kind of wastewater needs to be treated prior to discharging. Compared to other technologies for saline wastewater treatment, the microalgae process is considered to be ‘green’ or environmentally friendly as it generates no secondary pollutants and creates profit. To elucidate the issue, this review investigated the following: (1) the nature of saline wastewater; (2) adaptation of microalgae in saline wastewater; (3) pollutants’ remediation by microalgae in saline wastewater; (4) comparisons with other technologies; and (5) future perspectives. Most importantly, during microalgae process, the saline wastewater is transformed from a waste into a source for biofuel and pigment production. This trend implies to heal the environment, cut remediation expenses and raise revenue.

Simultaneous nutrition removal and high-efficiency biomass and lipid accumulation by microalgae using anaerobic digested effluent from cattle manure combined with municipal wastewater

BackgroundMicroalgae as a viable biodiesel feedstock show great potential to approach the challenges of energy shortage and environment pollution, but their economic feasibility was seriously hampered by high production cost. Thus, it is in urgent need to reduce the cost of cultivation and improve the biomass and lipid production of microalgae. In this work, anaerobic digestion effluent from cattle manure combined with municipal wastewater was used as a cost-effective medium for cultivating microalgae and expected to obtain high biomass. The pretreatment of anaerobic digested effluent containing dilution rate, sterilization and nutrient optimization was investigated. Then, initial pH and light intensity for algal growth, lipid production and wastewater purification were optimized in this study.ResultsScenedesmus sp. could grow rapidly in 10% anaerobic digestion effluent from cattle manure combined with secondary sedimentation tank effluent without sterilization. Optimum nutrient additives for higher biomass were as follows: glucose 10 g/L, NaNO3 0.3 g/L, K2HPO4·3H2O 0.01 g/L, MgSO4·7H2O 0.075 g/L and trace element A5 solution 1 mL/L. Biomass of 4.65 g/L and lipid productivity of 81.90 mg/L/day were achieved during 7-day cultivation accompanying over 90% of COD, NO3−-N, NH4+-N, and 79–88% of PO43−-P removal with optimized initial pH of 7.0 and light intensity of 5000 l×. The FAME profile in ADEC growth medium consisted in saturated (39.48%) and monounsaturated (60.52%) fatty acids with the 16- to 18-chain-length fatty acids constituting over 98% of total FAME.ConclusionsThis study proves the potential of anaerobic digested effluent combined with municipal wastewater for microalgae culture, and provides an effective avenue for simultaneous microalgal lipid production and treatment of two kinds of wastewater.

Roles of surfactants in pressure-driven membrane separation processes: a review

Surfactants widely exist in various kinds of wastewaters which could be treated by pressure-driven membrane separation (PDMS) techniques. Due to the special characteristics of surfactants, they may affect the performance of membrane filtration. Over the last two decades, there are a number of studies on treating wastewaters containing surfactants by PDMS. The current paper gives a review of the roles of surfactants in PDMS processes. The effects of surfactants on membrane performance were discussed via two aspects: influence of surfactants on membrane fouling and enhanced removal of pollutants by surfactants. The characteristics of surfactants in solution and at solid-liquid interface were summarized. Surfactants in membrane filtration processes cause membrane fouling mainly through adsorption, concentration polarization, pore blocking, and cake formation, and fouling degree may be influenced by various factors (feed water composition, membrane properties, and operation conditions). Furthermore, surfactants may also have a positive effect on membrane performance. Enhanced removal of various kinds of pollutants by PDMS in the presence of surfactants has been summarized, and the removal mechanism has been revealed. Based on the current reports, further studies on membrane fouling caused by surfactants and enhanced removal of pollutants by surfactant-aided membrane filtration were also proposed.

Design of an alternative approach for synergistic removal of multiple contaminants: Water splitting coagulation

The development of novel technologies for wastewater treatment provides a reliable pathway to solve the growing environmental issues. Control on process cost, increment of pollutant removal efficiency, and multi-system applicability are key points which should be carefully considered. Here in this work, a novel method of ‘water splitting coagulation (WSC)’, which involves the synchronous treatment of two kinds of wastewater that contain metal and organic contaminants was proposed. As an electrical based technique, WSC utilizes ‘water splitting’ in a bipolar membrane (BM) instead of ‘water electrolysis’ on electrodes to constructively produce a flocculating constituent (Ni(OH)x(2-x)+) by controlling the ‘hydroxide delivery’ and ‘cation delivery’ inside a BM and across a cation exchange membrane. The metal hydroxide is capable of absorbing textile dyes in (Dye)yNi(OH)x(2-x)+ form, which can be post-treated to produce useful resources. The alternative process has several advantages: 1) prevents the replacement of sacrificial anodes, 2) simultaneous removal of heavy metal and textile dyes, and 3) the recycling of valuable accompanying byproducts, and has great potential in the complex industrial wastewater treatment.

Fine-tuning selective layer architecture of hydrogel membrane towards high separation performances for engineered osmosis

Ultrathin and/or ultrasmooth selective layer is one of the paramount goals in membrane realm for maximizing separation efficiency and/or minimizing fouling tendency. Towards this goal, the architecture of hydrogel selective layer is finely tuned for the first time for improving engineered osmosis (EO) membrane performance. Through delicately controlling synthesis parameters, ultrathin selective layer as thin as 30 nm, and ultrasmooth selective layer with sub-1 nm roughness (the smoothest EO membrane in literature) are successfully synthesized respectively. Analysis of reverse osmosis (RO) experimental results reveals hydrogel layer resistance to water permeation is linearly reduced by 1.40 × 1013 m−1 as the layer is tailored thinner per 10 nm, which leads to the remarkable enhancement of water permeability by ~10 times from 0.49 L m−2 h−1 bar−1 of 500 nm thickness to 4.75 L m−2 h−1 bar−1 of 30 nm thickness. Pressure-retarded osmosis (PRO) and forward osmosis (FO) tests indicate 45-nm-thick hydrogel layer achieves the maximum separation efficiency in terms of specific water flux (JW/JS). Moreover, the mechanism for tuning hydrogel layer architecture is discussed on the basis of microscopic characterizations. This study sheds new light on ultrathin and ultrasmooth selective layer for promoting EO membrane to smartly tackle different kinds of wastewater.

Discussion on Factors Affecting the Removal of Organic Pollutants in Reverse Osmosis Concentrated Water of Landfill Leachate

Landfill leachate reverse osmosis concentrated water (RO concentrated water) is a kind of wastewater with high organic matter concentration, chemical oxygen demand (COD), turbidity, and chroma. The RO concentrated water is pretreated using coagulation method; then the coagulation effect of FeCl3, Fe2(SO4)3, Fe(NO3)3 and PAC on the leachate RO concentrated water is investigated in the experiment. The result shows that FeCl3 is the best coagulant. The removal rate of total organic compounds (TOC) reaches the highest (92.23%) under the condition of 8.0 g/L FeCl3 dosage, pH=6, 3 mg/L PAM, and 150 r/min rotation speed, and the removal rate of COD, NH3-N, and chroma are 73.91%, 28.3%, and 79%, respectively.

Natural gas processing wastewater management

The aim of this research is to focus on adequate treatment technology for handling wastewater discharged from natural gas processing industries. An Egyptian natural gas company located at Alexandria was selected for the study. The study represents a useful reference for treatment of such kind of wastewater. Dark Fenton, biological treatment and the combination of them were carried out. The wastewater produced by subject industries has high concentration of chemical oxygen demand, (COD=52665 mg/L), low biological oxygen demand (BOD=8350 mg/L) and low total suspended solids (TSS=370 mg/L). The value of BOD/COD was low (0.16) which indicates that this wastewater inhibits the metabolic activity of bacterial seed because of their refractory properties causing biodegradability to be difficult. Fenton oxidation treatment raise the BOD/COD to more than 0.36. Biological treatment using both aerobic and anaerobic bioreactors for the treatment of mixture of Fenton pretreated gas processing wastewater and sewage gave satisfactory results. The subsequent anaerobic treatment using UASB reactor at optimum HRT [18h] qualifies the produced wastewater for discharge into the sewerage system. The additional aerobic treatment using the continuous-flow activated sludge at 12h HRT qualifies the treated wastewater for discharge into the sea.

Comprehensive review on wastewater discharged from the coal-related industries – characteristics and treatment strategies

Wastewaters discharged from various coal-related activities deteriorate fresh water quality and inflict possibilities of groundwater contamination. Their characteristics mostly depend on the parent coal properties, though some of the pollutants are cyanide, thiocyanate, ammonia, phenol, heavy metals and suspended solids. This paper has reviewed the treatment techniques along with the characteristics of all such kinds of wastewater and also identified the challenges and future perspectives. Primarily, demineralization of coal can attenuate and control release of pollutants in wastewaters if implemented successfully. Mine water from non-lignite mines can be purified using simple techniques, for its reutilization. Acidic mine water and leachates can be treated using passive bioreactors with microbial activity, different organic substrates and limestone drains. Additionally bio-electrochemical systems, membranes, macrocapsules, zeolite filters, ores, physical barriers, and aquatic plants can also be used at various stages. Coal washery wastewater can be treated using natural coagulants obtained from plant extracts along with conventional coagulants. Nitrification and denitrification bacteria fixed in reactors along with activated carbon and zero-valent iron can treat coke oven wastewater. Some other sophisticated techniques are vacuum distillation, super critical oxidation, nanofiltration and reverse osmosis. Practical use of these methods, wisely in an integrated way, can reduce freshwater consumption.

Application of natural mixed bacteria immobilized carriers to different kinds of organic wastewater treatment and microbial community comparison

Although many literatures have reported that biomass materials had been used for water treatment, most of the biomass materials were directly used for adsorbing toxic or organic substances. In this research, modified pine bark and corn straw were used to prepare the high-efficiency and low-cost activated sludge immobilized materials. By treating phenol wastewater and ordinary organic wastewater, various factors influencing the treatment effect were investigated. The results showed that the immobilized biological carriers had good effects on the treatment of two kinds of wastewater. The removal efficiency of the phenol wastewater reached 100% in 24 h, and the removal efficiency of ordinary organic wastewater reached 95.5% in 96 h. The results of microbial community analysis showed that the abundance of the immobilized carrier and that of the original sludge was similar. But when treating different wastewater, the number and proportion of microorganisms were significantly different.

Microalgae cultivation for municipal and piggery wastewater treatment in Brazil

Microalgae are a source of high-valuable products covering a wide range of applications. However, costs incurred by cultivating them make it an expensive process. The combination of wastewater treatment and microalgae cultivation is a viable option to reduce expenses related to cultivation. However, municipal wastewater from the centralized Brazilian sanitation system is highly diluted, and it is technically and economically impractical to use it for microalgae cultivation. As an alternative, diluted effluent can be mixed with a different kind of wastewater, aiming to increase the nutrient concentration (carbon, nitrogen and phosphorus) for microalgae cultivation. In this study, microalgae cultivation and wastewater mixture (municipal and piggery wastewater) treatment were monitored for four weeks. The pilot treatment system consisted of UASB as pre-treatment and Chlorella sorokiniana cultivation in three flat panel photobioreactors. High UASB efficiency was obtained in organic matter removal (> 90%), even with a large variability of initial mixture characteristics. C. sorokiniana production reached about 1 g L−1, with an average removal of dissolved inorganic carbon, orthophosphate and ammonia around 46 to 56%, 40 to 60% and 100%, respectively. Possible solutions to improve the microalgae growth and the system treatment are discussed.

Evaluation of biodegradability and environmental impact of biowaste leachate

As the world’s population and urbanization have significantly increased in the past few decades, the generation of municipal solid waste has accelerated on global scale. The biowaste disposal, which is an integral part of municipal waste, leads to leachate production. These kinds of wastewater are characterized by complex composition with very high concentrations of organic and inorganic pollution substances and toxicity, which may have harmful impact on the environment. This study investigated the physico-chemical and biological characterization of leachate from biowaste. The experiments were conducted in batch performance with initial concentration of leachate, expressed as chemical oxygen demand, 12.21 ± 0.46 g O2/L and pH value 4.05 ± 0.13. Obtained results showed that leachate from biowaste have high value of chemical oxygen demand, toxicity and low pH. Overall efficiency of the process of aerobic biodegradation was 89 %. The abundance of viable bacterial cells and development of activated sludge flocs during the experiment confirmed the biodegradability of leachate from biowaste.

Vacuum evaporation and reverse osmosis treatment of process wastewaters containing surfactant material: COD reduction and water reuse

The problem of process wastewater arises not only in fine chemical industry, but also where water is used for washing. In these cases, surfactant material is given to the water, so its washing capability is enhanced. The used water contains surfactant material and dirt. It has high chemical oxygen demand (COD) resulting in serious environmental problems. Finding a solution is inevitable because of the high wastewater fine which has to be paid by the factories if wastewater is emitted without any treatment. A suitable method had to be found that follows the principles of circular economy, so the industrial cycles can be closed like in nature and the water can be reused. Our designed method focuses on different kinds of wastewater containing special surfactant materials, and it has chemical industry relations. The treatment should have reduced the high COD value below to 1000 mgO2/L, which is the discharge limit. It was also aimed that instead of discharging, the treated water could be recycled and reused. Our new physicochemical treatment process consists of a vacuum evaporation method that reduces COD from c.a. 8400 to 1100 mgO2/L. Both laboratory and pilot experiments were investigated. Since this COD value was not satisfactory, a subsequent reverse osmosis membrane operation was also applied. This two-step method, vacuum evaporator followed by reverse osmosis, was able to reduce the COD in wastewater containing surfactant/washing material below the discharge limit. 100 mgO2/L could be reached with using TriSep™ X201 membrane. Penalty calculation and cost estimation also demonstrate the efficiency of our novel method.Graphical abstract

Ecotoxicological study of landfill leachate treated in the ANAMMOX process

Abstract The exacerbated production of solid residues represents a major problem in the management and handling of urban wastes. The by-product of stored municipal and industrial solid waste production is landfill leachate. Leachate is characterized by a high concentration of organic compounds, ammonia, and the presence of heavy metals. Because of its composition, this kind of wastewater can cause serious environmental pollution and should be treated to reduce its toxic effects. Increasingly, the interest is directed to the application of the ANAMMOX (anaerobic ammonium oxidation) process for the landfill leachate treatment. In this study, for the first time, the effect of treatment with the ANAMMOX process on the toxicity of leachate was investigated. Based on the research performed in this study, it could be stated that the untreated landfill leachate from the municipal landfill and the influent of the ANAMMOX reactor present phytotoxicity to Lemna minor, due to a correlation of high concentrations of organic compounds, heavy metals, such as Cd2+, Cu2+, Zn2+, and the presence of an unionized form of ammonia (NH3). The results of the Allium cepa test demonstrated that the treatment was not efficient in eliminating the genotoxic substances that are responsible for the mutagenic potential in the effluent. This article has been made Open Access thanks to the kind support of CAWQ/ACQE (https://www.cawq.ca).

Intermittent light and microbial action of mixed endogenous source DOM affects degradation of 17β-estradiol day after day in a relatively deep natural anaerobic aqueous environment.

All kinds of wastewaters containing steroid estrogens (SEs) and mixed endogenous source dissolved organic matter (DOM) enter natural water environments with intermittent illumination where microbial action occurs in a relatively deep natural aqueous environment. The role of mixed endogenous source DOM in SEs' biodegradation and photochemical degradation in such environments was studied using 17β-estradiol (E2) in laboratory experiments under anaerobic conditions. The experimental results show that microbial action can improve the optical properties and electron transfer capability of mixed endogenous source DOM, promoting photodegradation and biodegradation. Intermittent illumination attenuates DOM's electron transfer capacity and its chromophore groups, but it improves the bioavailability of low molecular weight dissolved organic matter which promotes microbial growth under anaerobic conditions. DOM-mediated co-degradation by light and microbial action over three days was better than either individually. The presence of Fe(III) promoted electron transfer, and Fe(III)-DOM complexes accelerated energy transfer under irradiation, enhancing photodegradation. Any remaining estrogens will continue to degrade, most effectively in well-aerated waters with sufficient illumination.

Kinetics and performance of coagulation process using Mucuna seed shell for the treatment of paint wastewater

The use of coagulation technique in the treatment of different kinds of wastewaters has been employed using various coagulants. In this study, the focus is on the efficiency of coagulation process ...

Performance and kinetic modeling of an aerated submerged fixed-film bioreactor for BOD and nitrogen removal from municipal wastewater

The current study investigated the biochemical oxygen demand (BOD) and nitrogen removal from actual municipal wastewater using an up-flow aerated submerged fixed-film (ASFF) bioreactor. The experiments were conducted using a 14.8 L bioreactor with polypropylene packing media. For the first time, three kinetic models (first-order, Grau second-order, and modified Stover-Kincannon) and evolutionary polynomial regression (EPR) were considered in evaluating the substrate removal in an ASSF bioreactors fed with actual municipal wastewater. The applied BOD5 concentrations of actual municipal wastewater varied in the range of 198 ± 12 to 213 ± 16 mg/L. The system was able to achieve a 90%–98% reduction in BOD5, while the organic loading rates (OLRs) were between 0.59 and 2.06 kg BOD5/m3.d. Disregarding certain experimental conditions, the effluent BOD5 concentrations were not more than 20 mg/L throughout the experiments. When the hydraulic retention time (HRT) was reduced from 8 to 2.5 h, the ammonia removal efficiency dropped from 94.0% to 78.9%. Moreover, a direct relationship was observed between the applied OLR and the ratio of volatile solids to total solids. Conversely, an inverse correlation was seen between the reduction in total suspended solids and the OLR. Although several studies have evaluated the aerobic treatment of different kinds of wastewaters, none of the studies contained a kinetic study relevant to ASFF bioreactors treating an actual municipal wastewater. Among the investigated models, the modified Stover-Kincannon and Grau second-order models were found to be the best to describe the present system and well-fitted with the data sets.

Coupling of Nanofiltration and Thermal Fenton Reaction for the Abatement of Carbamazepine in Wastewater.

The complete removal of biorecalcitrant xenobiotics, including most notably the pharmaceutical pollutants, by advanced oxidation processes is often difficult to be reached in urban or industrial wastewater because of the high concentration of organic and inorganic scavengers that compete with the xenobiotics for the oxidizing species. This work investigates a coupled treatment train in which wastewater effluents are pretreated with a negatively charged loose nanofiltration (NF) membrane (HydraCoRe70, made up of sulfonated polyethersulfone) to enhance the removal of xenobiotics with the thermal Fenton process. Carbamazepine (CBZ), a drug prescribed mainly for epilepsy treatment, is used here as a model xenobiotic. After optimizing the conditions for separation and degradation, the NF–Fenton approach was applied to both synthetic wastewater and real samples to assess the overall efficiency of CBZ removal. The Fenton degradation of CBZ was drastically enhanced in nanofiltered samples, thanks to the removal by the membrane of nearly all organic matter that would otherwise consume the reactive oxidizing species (e.g., the hydroxyl radical). On the basis of a preliminary treatment cost analysis, it can be concluded that the combined process is potentially applicable to the treatment of several kinds of wastewaters (e.g., industrial ones) to favor the removal of biorecalcitrant contaminants. Key cost savings of NF–Fenton concern the lower amounts of Fenton reagents needed to degrade CBZ and (even more importantly) the decreased levels of acids and bases for pH adjustment before and after the oxidative process because of the lower buffer capacity of the NF permeate compared to feed wastewater, after the removal by the NF of many inorganic ions and most organic carbon.

Characteristics and potential treatment technologies for different kinds of wastewaters

Characteristics and potential treatment technologies for different kinds of wastewaters

Conceptual design of an extractive distillation process for the separation of azeotropic mixture of n-butanol-isobutanol-water

In many chemical processes, large amounts of wastewater containing butanol and isobutanol are produced. Given that n-butanol-isobutanol-water can form triple azeotrope, high-purity butanol cannot be recovered from the wastewater by ordinary distillation. To economically and effectively recover butanol from this kind of wastewater, 1,4-butanediol is selected as an extractant to break the formation of the azeotropes, and a double-effect extractive distillation process is proposed. The conceptual design of the proposed process is accomplished based on process simulation. With the proposed process, the purity of recovered butanol and water is greater than 99.99 wt%. In comparison with the conventional azeotropic distillation process, economic analysis shows that the operating cost of the proposed process is lower: when the capacity of wastewater treatment is 100 t·h− 1, the total operating cost decreases by 5.385 ×106 USD per year, and the total annual cost of the new process decreases by 5.249 ×106 USD per year. In addition, in the extractive distillation system, variable effects on separation purities and cost are more complex than those in the ordinary distillation system. The method and steps to optimize the key variables of the extractive distillation system are also discussed in this paper and can provide reference for similar studies.