Means Of Wastewater Treatment Research Articles

Recent Advances in Plasmonic Chemically Modified Bioactive Membrane Applications for the Removal of Water Pollution

Population growth has reduced the available freshwater resources and increased water pollution, leading to a severe global freshwater crisis. The decontamination and reuse of wastewater is often proposed as a solution for water scarcity worldwide. Membrane technology is a promising solution to the problems currently facing the water and wastewater treatment industry. However, another problem is the high energy costs required to operate systems which use membranes for water treatment. In addition, membranes need to be replaced frequently due to fouling and biofouling, which negatively affect water flow through the membranes. To address these problems, the researchers proposed membrane modification as a solution. One of the exciting applications of plasmonic nanoparticles (NPs) is that they can be used to modify the surface of membranes to yield various properties. Positive feedback was reported on plasmonic-modified membranes as means of wastewater treatment. However, a fundamental gap exists in studies of plasmonic membranes’ performance and applications. Given the importance of membrane technology for water and wastewater treatment, this paper reviews recent advances in the development of plasmonic chemically modified bioactive membranes and provides a perspective for future researchers interested in investigating modified membranes.

The Problem of Water Resources Pollution with Active Pharmaceutical Substances and the Possibility of Its Solving

Environmental pollution by pharmaceutical products has become one of the most significant problems in the modern world. It also touched upon the countries of Central Asia, including Kazakhstan. Pharmaceutical production in the country is growing rapidly, with drugs widely available to the population. This inevitably leads to the fact that a significant part of medicinal compounds gets into the environment and, in particular, into water bodies. It is obvious that pollution of the aquatic environment with various active pharmaceutical compounds harms the aquatic ecosystem, worsens the quality of water, and, subsequently, human health. That is why the need for the inactivation of pharmaceutical products polluting the aquatic environment is so urgent. The objectives of this study were to identify pharmaceutical compounds in the aquatic environment of Kazakhstan and to test the effectiveness of activated carbon as a means for wastewater treatment by adsorption.

Variables Governing Photosynthesis and Growth in Microalgae Mass Cultures

Since the 1950s, microalgae have been grown commercially in man-made cultivation units and used for biomass production as a source of food and feed supplements, pharmaceuticals, cosmetics and lately biofuels, as well as a means for wastewater treatment and mitigation of atmospheric CO2 build-up. In this work, photosynthesis and growth affecting variables—light intensity, pH, CO2/O2 exchange, nutrient supply, culture turbulence, light/dark cell cycling, biomass density and culture depth (light path)—are reviewed as concerns in microalgae mass cultures. Various photosynthesis monitoring techniques were employed to study photosynthetic performance to optimize the growth of microalgae strains in outdoor cultivation units. The most operative and reliable techniques appeared to be fast-response ones based on chlorophyll fluorescence and oxygen production monitoring, which provide analogous results.

EFFICIENCY OF COAGULATION-FLOCCULATION PROCESS IN THE TREATMENT OF ABATTOIR EFFLUENT

The use of coagulation-flocculation process as means of wastewater treatment is gradually becoming more popular. This research work is to evaluate the efficiency of coagulation-flocculation process in the treatment of abattoir effluent. Samples of abattoir effluent were collected from a slaughterhouse at Ede, Nigeria, and Alum was used in the coagulation-flocculation treatment of the effluent. The physico-chemical and bacteriological analyses of the untreated and treated effluent were carried out and these were used in determining the efficiency of the treatment process. The values obtained (from the physico-chemical and bacteriological analyses) were also compared with the effluent standard of Environmental Protection Agency (EPA). Coagulation-flocculation process is performed efficiently in reducing the contaminant level of Colour, TDS, Turbidity, Conductivity, TSS, Total Hardness, COD, Coliform, metals and other pollutants from the effluent.

Environmental aspect and applications of nanotechnology to eliminate COVID-19 epidemiology risk

Herein, we discuss fast development of the new coronavirus disease COVID-19, emerged in late 2019 in Wuhan, Hubei Province, China, the ground zero of the coronavirus pandemic, and associated with relatively high mortality rate. COVID-19 risk originates from its ability to transmit easily from person to person through the respiratory droplets released during sneezing, breathing, talking, singing, or coughing within a range of nearly 1.5–2 m. The review begins with an overview of COVID-19 origin and symptoms that range from common cold to severe respiratory illnesses and death. Then, it sheds light on the role of nanotechnology as an effective tool for fighting COVID-19 via contributions in diagnosis, treatment, and manufacture of protective equipment for people and healthcare workers. Emergency-approved therapeutics for clinical trial and prospective vaccines are discussed. Additionally, the present work addresses the risk of severe acute respiratory syndrome coronavirus transmission via wastewater and means of wastewater treatment and disinfection via nanoscale materials. The review concludes with a brief assessment of the government's efforts and contemporary propositions to minimize COVID-19 hazard and spreading.

Criteria and methodological approach to assessment of wastewater treatment methods

When assessing water quality, there are several criteria. In the first place is the standardization factor, including limits on the withdrawal of water from sources, limits on the discharge of wastewater and the maximum mass of pollution for each ingredient. Further, water use implies three main types: 1) hygienic requirements for drinking water; 2) the quality of water for cultural purposes; 3) to the waters of fishery purposes. With the transition of Russia to the market, fundamentally changed attitudes towards ecology and raw materials, to technical policy, improving methods and means of wastewater treatment in order to extract useful elements from them and rational waste disposal. However, the problem of priority protection of domestic “know-how”, especially in environmental issues, aggravating the difficult social environment, remained relevant. Thus, there is a need to develop criteria and methods for minimizing costs while maintaining natural sources and wastewater treatment. There is a need to calculate socio-economic efficiency when it comes to the introduction of non-waste technologies related to the environment, which improves the social situation and the country’s prestige on a global level. Consider some points linking these problems with the solution of the problems of economics and ecology. It is necessary to highlight such aspects of the problem as: monitoring of harmful components, the cost-effectiveness of water treatment methods and the development of new methods for the production of effective sorbents and reagents. A separate article is the non-waste processes. In industrialized countries, the same problems exist that are often solved by rational disposal methods.

Artificial transpiration: an efficient means of waste-water treatment

Artificial transpiration: an efficient means of waste-water treatment

Progress in microalgae cultivation photobioreactors and applications in wastewater treatment: A review

Using microalgae to treat wastewater has received growing attention in the world because it is regarded as a novel means for wastewater treatment. It is commonly recognized that large-scale cultivation and commercial application of microalgae are limited by the development of photobioreactor (PBR). Although there are a lot of PBRs for microalgae pure cultivation which used culture medium, specialized PBRs designed for wastewater treatment are rare. The composition of wastewater is quite complicated; this might cause a very different photosynthetic effect of microalgae compared to those grown in a pure cultivation medium. Therefore, PBRs for wastewater treatment need to be redesigned and improved based on the existing PBRs that are used for microalgae pure cultivation. In this review, different PBRs for microalgae cultivation and wastewater treatment are summarized. PBR configurations, PBR design parameters and types of wastewater are presented. In addition, the wastewater treatment efficiency and biomass productivity were also compared among each type of PBRs. Moreover, some other promising PBRs are introduced in this review, and a two-stage cultivation mode which combines both closed and open system is discussed as well. Ultimately, this article focuses on current problems and gives an outlook for this field, aiming at providing a primary reference for microalgae cultivation by using wastewater. Keywords: microalgae cultivation, wastewater treatment, photobioreactor (PBR), review DOI: 10.3965/j.ijabe.20171001.2705 Citation: Han T, Lu H F, Ma S S, Zhang Y H, Liu Z D, Duan N. Progress in microalgae cultivation photobioreactors and applications in wastewater treatment: A review. Int J Agric & Biol Eng, 2017; 10(1): 1–29.

Nitrogen doped nanocrystalline semiconductor metal oxide: An efficient UV active photocatalyst for the oxidation of an organic dye using slurry Photoreactor

Water pollution is a cause for serious concern in today's world. A major contributor to water pollution is industrial effluents containing dyes and other organic molecules. Waste water treatment has become a priority area in today's applied scientific research as it seeks to minimize the toxicity of the effluents being discharged and increase the possibility of water recycling. An efficient and eco-friendly way of degrading toxic molecules is to use nano metal-oxide photocatalysts. The present study aims at enhancing the photocatalytic activity of a semiconductor metal oxide by doping it with nitrogen. A sol–gel cum combustion method was employed to synthesize the catalyst. The prepared catalyst was characterized by FT-IR, XRD, UV-DRS, FESEM and AFM techniques. UV-DRS result showed the catalyst to possess band gap energy of 2.97eV, thus making it active in the UV region of the spectrum. Its photocatalytic activity was evaluated by the degradation of a model pollutant-Orange G dye, under UV light irradiation. Preliminary experiments were carried out to study the effects of pH, catalyst dosage and initial dye concentration on the extent of dye degradation. Kinetic studies revealed that the reaction followed pseudo first order kinetics. The effect of electrolytes on catalyst efficiency was also studied. The progress of the reaction was monitored by absorption studies and measuring the reduction in COD. The catalyst thus prepared was seen to have a high photocatalytic efficiency. The use of this catalyst is a promising means of waste water treatment.

Separation of Zn(II) and Cd(II) ions from Synthetic Waste Water by Adsorption on Activated Carbon Derived from Tridax procumbens

The use of activated carbon derived from Tridax procumbens for the treatment of waste water containing heavy metals is an innovative method. It constitutes a simple, effective and economical means for waste water treatment. Adsorption of toxic heavy metals viz. Zn(II) and Cd(II) were studied from synthetic waste water on activated biocarbon derived from Tridax procumbens. Batch adsorption experiments were performed with activated biocarbon as a function of pH, contact time and amount of activated biocarbon. The most favourable pH required for maximum adsorption was found to be 3.6 and 3.8 for Zn(II) and Cd(II) respectively. The maximum contact time for the equilibrium condition was found to be 180 min. The maximum efficiencies of Zn(II) and Cd(II) removal by biocarbon were 97.74 % and 90.62 % respectively. When the amount of activated biocarbon was increased, percentage removal of metal ions also increased for the system containing upto 3.0 g of biocarbon. Beyond this no appreciable change was observed. The linear Langmuir and Freundlich models were applied to describe equilibrium isotherms and both models fitted well.

Synthesis of Poly(vinyl alcohol)/Chitosan/Titanium Oxide Beads

The application of photocatalytic beads in wastewater treatment application has gained attention of many researchers. In this study, the synthesised poly(vinyl alcohol)/chitosan/Titanium oxide (PVA/CS/TiO2) beads has been considered as a promising alternative to conventional means of wastewater treatment. The present study has successfully synthesised PVA/CS/TiO2 beads through simple dropwise method in which varied concentration of CS from 1.0 g to 2.5 g. Morphological analysis of the synthesised PVA/CS/TiO2 beads investigated by the FE-SEM technique revealed that porous beads were obtained regardless of the varied CS concentration content. Furthermore, solubility and swelling properties investigation of the beads were also performed within the prescribed time of 24h in three different medium which were acidic, distilled water and alkaline solution. Result of solubility test proved that PVA/CS/TiO2 beads were insoluble only in distilled water and alkaline solution. However, the beads were found to dissolve in acidic solution due to the CS content. Meanwhile, the swelling test revealed that increased concentration of CS leads to swelling of beads in distilled water and alkaline solution. Results revealed that beads with the highest CS composition which is 2.5 g recorded 82.6% and 118.4% of swelling in distilled water and alkaline solution, respectively. In the mean time, beads with the lowest CS composition which is 1.0 g only swell for 65.8% and 93.3% in distilled water and alkaline solution, respectively. As a conclusion, the synthesised beads in this study is feasible to be applied in natural to alkaline environment.

Influence of Season and Plant Species on the Abundance and Diversity of Sulfate Reducing Bacteria and Ammonia Oxidizing Bacteria in Constructed Wetland Microcosms

Constructed wetlands offer an effective means for treatment of wastewater from a variety of sources. An understanding of the microbial ecology controlling nitrogen, carbon and sulfur cycles in constructed wetlands has been identified as the greatest gap for optimizing performance of these promising treatment systems. It is suspected that operational factors such as plant types and hydraulic operation influence the subsurface wetland environment, especially redox, and that the observed variation in effluent quality is due to shifts in the microbial populations and/or their activity. This study investigated the biofilm associated sulfate reducing bacteria and ammonia oxidizing bacteria (using the dsrB and amoA genes, respectively) by examining a variety of surfaces within a model wetland (gravel, thick roots, fine roots, effluent), and the changes in activity (gene abundance) of these functional groups as influenced by plant species and season. Molecular techniques were used including quantitative PCR and denaturing gradient gel electrophoresis (DGGE), both with and without propidium monoazide (PMA) treatment. PMA treatment is a method for excluding from further analysis those cells with compromised membranes. Rigorous statistical analysis showed an interaction between the abundance of these two functional groups with the type of plant and season (p < 0.05). The richness of the sulfate reducing bacterial community, as indicated by DGGE profiles, increased in planted vs. unplanted microcosms. For ammonia oxidizing bacteria, season had the greatest impact on gene abundance and diversity (higher in summer than in winter). Overall, the primary influence of plant presence is believed to be related to root oxygen loss and its effect on rhizosphere redox.

Biological Trickling Filters as the Sole Means of Wastewater Treatment – Does It Work?

Biological Trickling Filters as the Sole Means of Wastewater Treatment – Does It Work?

Efficient adsorption-photodegradation of 4-nitrophenol in aqueous solution by using ZnO/HZSM-5 nanocomposites

In this paper, the newly prepared ZnO/HZSM-5 nanocomposites were suggested as the promising alternative materials for conventional means of waste water treatment. The combination effect of adsorption–photodegradation for the removal of 4-nitrophenol (4-NPh), as a biorefractory pollutant, occurred successfully when 7 wt.% of ZnO nanoparticles were incorporated in HZSM-5 zeolite. It was found that both the hydrophobicity and size-selectivity of HZSM-5 toward 4-NPh enhanced the adsorption process. The photodegradation of 4-NPh solutions was performed under UV irradiation and the influence of various parameters such as ZnO loading amount, pH dependence and initial concentration of 4-NPh were investigated. The results indicated that during the fixed reaction time (90 min) about 91% total organic carbon of solution, containing 4-NPh (20 mgl − 1 ) was removed at pH = 5. Batch kinetic studies were conducted to evaluate the adsorption–photodegradation process. The pseudo-second-order fit well over the range of reaction time. It can be suggested that encapsulating ZnO clusters in the zeolites is a proper way to inhibit the agglomeration of ZnO nanoparticles and also to retard the recombination of photogenerated electron–hole in photocatalytic activity.

Wastewater garden—a system to treat wastewater with environmental benefits to community

Many communities and villages around the world face serious problems with lack of sanitation especially in disposing of the wastewater-black water and grey water from the houses, or wash outs from animal rearing sheds. Across the world diverting wastewater to the surroundings or to the public spaces are not uncommon. This is responsible for contaminating drinking water sources causing health risks and environmental degradation as they become the breeding grounds of mosquitoes and pathogens. Lack of collection and treatment facilities or broken down sewage systems noticed throughout the developing world are associated with this situation. Diverting the wastewater to trees and vegetable gardens was historically a common practice. However the modern world has an array of problems associated with such disposal such as generation of large quantity of wastewater, unavailability of space for onsite disposal or treatment and increase in population. This paper considers the wastewater garden as a means for wastewater treatment and to improve the vegetation and biodiversity of rural areas. This can also be implemented in urban areas in association with parks and open spaces. This also highlights environmental safety in relation to the nutrient, pathogen and heavy metal content of the wastewater. The possibilities of different types of integration and technology that can be adopted for wastewater gardens are also discussed.

Potential of natural treatment systems for the reclamation of domestic sewage in irrigated agriculture

Experimental results from various pilot-scale configurations of natural treatment systems as means for wastewater treatment are demonstrated. Various systems consisting of waste stabilization ponds, shallow algal ponds and water hyacinth ponds were operated in parallel, series or mixed arrangement in order to find the optimum setting that enables efficient effluent quality to be reused for agricultural purposes. The results indicate that waste stabilization ponds were very efficient for wastewater treatment, especially in terms of organic and nutrient load removal, achieving an effluent quality able to be used for restricted irrigation. However, coliform numbers were not always consistent with the proposed guidelines. To cope with the problem, a modified configuration employing water hyacinth ponds, waste stabilization ponds and final water hyacinth ponds is proposed. The results indicate that the latter system provides a considerable degree of treatment compared to previous systems, yielding an effluent able to be used for irrigated agriculture and related applications.

Lead Removal from Wastewater Using Cu(II) Polymethacrylate Formed by Gamma Radiation

In this work Cu(II) polymethacrylate (Cu(II)PMA) is obtained through gamma irradiation of the corresponding monomer. The polymer was mixed with Pb(II) aqueous solutions to remove this pollutant from the liquid phase. The Pb(II) removal occurs via a Langmuir-type adsorption mechanism, that was found to be a function of the contact time between the polymer and the solution. A 60% decrease of Pb(II) concentration in the liquid phase was achieved. The polymer was characterized using scanning electron microscopy (SEM), energy dispersion analysis (EDX), electron paramagnetic resonance (EPR),X-ray diffraction and FT-IR. The use of Cu(II)PMA for the treatment of wastewater containing heavy metals is an innovative method that constitutes a simple, effective and economical means for wastewater treatment.

Microorganism removal in wastewater stabilisation ponds in maracaibo, Venezuela

Waste stabilisation ponds are an efficient means of wastewater treatment in many parts of the world wherever suitable land is available at reasonable cost and solar energy is an abundant energy resource. This study evaluated the removal of total coliforms TC, faecal coliforms FC and coliphages C in waste stabilisation ponds functioning as a pilot system in the tropical climate of Maracaibo, Venezuela. Sampling points included raw sewage and each pond effluent. Turbidity, pH and temperature were recorded. The results for raw sewage show average levels of 4.1×106 TC, 2.8×106 FC and 7.0×105 C/100mL. Temperature, pH and turbidity ranges between 26–31°C, 6.2–9.5 and 15–98 NTU respectively. Removal of microorganisms in the three systems ranged between 93–98%. Despite the high removal efficiency of microorganisms, the final effluents showed average counts of 5.4×104−1.4×105 TC, 5.2×104−1.3×105 FC and 1.6×104−4.7×104 C/100mL. This study shows that the microbiological quality of the final effluents did not achieve the WHO water quality requirement for FC (103/100mL); therefore, they cannot be used for irrigation. Additional treatments, such as slow sand filtration, are needed in order to improve the quality of the water.