Wastewater Recovery Research Articles

Controllable H2S supply via membrane contactors for safe and efficient arsenic precipitation from acidic wastewater

Sulfide precipitation is a popular technique for the treatment and resource recovery of arsenic-containing dirty acid wastewater. However, this approach frequently suffers from toxic hydrogen sulfide (H2S) escape and agent wastage issues. Herein, a safe and efficient technique is proposed based on a polytetrafluoroethylene membrane contactor wherein the mass transfer resistance of the gas, membrane, and liquid phases can be easily and independently regulated to control the H2S supply. Additionally, H2S is transferred in bubble-free form, fundamentally avoiding the issue of gas escape, and uniform membrane distribution contributes to evenly distributed H2S delivery. The results demonstrated that 99.3% arsenic precipitation could be achieved and the H2S emission ratio was limited to <0.12%, which was significantly better than traditional methods. Thus, highly efficient separation and resource recovery of heavy metals in wastewater can be achieved using this unique and controllable low-dose H2S supply method. The separation factor between copper and arsenic was as high as 7490.9. This study provides a safe, reliable, and promising new approach for the treatment of arsenic-containing acidic wastewater.

Soil amendments and water management to improve attenuation and recovery of wastewater originated nutrients through a vegetation filter

Vegetation filters (VFs) are on-site wastewater (WW) treatments that can be considered as a nature-based solution (NbS). They are green infrastructures that provide several environmental benefits such as non-potable water reuse, contamination reduction, biomass production, landscaping improvements and CO2 fixation, among others. However, nutrient leaching, especially nitrate, partially exists. To overcome this limitation, operational parameters related to the irrigation water management and soil amendments were tested in a real system receiving WW from an office building operated along 4 years.The attenuation of N is improved (up to 83%) in the vadose zone by boosting biodegradation. Lower hydraulic loads and more frequent irrigation events using drippers and the incorporation of woodchips as a layer above the topsoil promote denitrification processes. Changes in organic carbon characteristics also confirm that biodegradation is enhanced.P attenuation is a result of abiotic processes, mainly driven by chemical equilibriums between the liquid and the sorbed and/or precipitated phase and, when uncontrolled changes in the WW quality occurs, removal efficiency is negatively affected. However, only 10% of the samples collected at 45 cm depth present concentrations above 2 mg/L. The woodchips application does not seem to ameliorate P removal regardless of the application method.The implemented measures allow higher soil water content, infiltration and groundwater recharge and prevents aquifer contamination.

Redox-active sp2-c connected metal covalent organic frameworks for selective detection and reductive separation of uranium

It is economically desirable to develop a material that can simultaneously detect and recover uranium. Herein, a CC-bridged two-dimensional metal-covalent organic framework (Cu-BTAN-AO MCOF) was constructed by condensation of metal single crystals with a rigid structure (Cu3(PyCA)3) and cyano monomers (BTAN) via Knoevenagel reaction for simultaneous detection and adsorption of uranium. The amidoxime group within the pore and the presence of unsaturated Cu(I) in the framework facilitate the adsorption of uranyl ions onto the amidoxime group, leading to fluorescence quenching via the photoinduced electron transfer (PET) mechanism, achieving a detection limit of as low as 167 nM uranyl ions. Furthermore, Cu-BTAN-AO demonstrates exceptional efficiency in capturing uranium from wastewater characterized by rapid kinetics and superior selectivity. It is noteworthy that Cu-BTAN-AO is the first example of simultaneous detection, adsorption and chemical reduction of uranium using metal centers and functional groups in MCOF, indicating that Cu-BTAN-AO has great potential for the detection and recovery of uranium-containing wastewater. This design strategy may also be applicable to advancing sensing and energy materials for other important metal ions.

Excellent acid resistance and MXene enhanced photothermal conversion of bilayered porous solar evaporator fabricated by palygorskite and pectin

Acidic wastewater comes from a wide range of sources in industrial process. The traditional treatment method of acidic wastewater is acid-base neutralization which consumes a lot of chemicals. In recent years, much attention has been paid to the treatment of wastewater through solar interfacial evaporation. However, many of the reported evaporators present challenges in terms of poor acid resistance and costly raw materials. In this article, the three-dimensional porous MXene/PPAL aerogel was prepared by directional freeze-drying using inexpensive Palygorskite (Pal) and renewable pectin, then a moderate amount of MXene was sprayed onto the aerogel surface to create a double-layer solar evaporator. The prepared evaporator exhibited great mechanical properties with a compressive strength of 0.85 MPa at 70 % strain, and high vapor rate of 1.5474 kg m−2 h−1 that equals 94.7 % photothermal conversion efficiency. Furthermore, photothermal conversion efficiency of the solar evaporator in 5 % H2SO4 solution (pH = 1) was 90.2 %, which was only slightly different from that in pure water. The results provided a new technology that easy recovery of acidic wastewater and reused treated water from industrial acidic wastewater through economical and efficient solar interfacial evaporation.

Electrocoagulation process for phosphate recovery of agricultural wastewater: effect of calcium adding, voltage, and time.

Recovery of valuable resources, such as phosphate recovery from wastewater, can help close the nutrient cycle and is interesting to investigate. This study aims to evaluate phosphate recovery and set aside TOC, OC, and IC in agricultural wastewater using electrocoagulation with a helix electrode configuration. This study employed the Response Surface Methodology (RSM) for statistical analysis and modeling, utilizing a central composite design (CCD). Variation of calcium concentration (2-7mg/L), voltage (15-45V), and electrocoagulation time (5-15min) was applied in an electrocoagulation reactor with a helix-shaped stainless steel cathode and a solid cylindrical Mg anode. Based on RSM analysis, electrocoagulation with a helical electrode configuration significantly affects phosphate recovery and the removal of TOC, OC, and IC when treating agricultural wastewater. Under operating conditions of 15V, 15min time, and 2mg/L calcium concentration, we achieved the lowest phosphate concentration of 0.003mg/L (99.74% reduction). The highest TOC allowance is > 100% of the initial concentration, the TC allowance is 55.79%, and the IC allowance is 30.91%. The formation of metal hydroxides affects the efficiency of TOC removal in the electrocoagulation process, and higher electrolysis times lead to higher TOC removal efficiency. Higher voltages also improve the coagulation and flotation processes in the reactor. Calcium concentration plays a role in enhancing the flocculation process and binding phosphonates from wastewater.

Incorporation of zeolitic imidazolate framework-8 (ZIF-8) in the polyamide and polysulfone layers of forward osmosis membranes for enhancing aquaculture wastewater recovery and PPCPs removal

Wastewater recovery is essential to alleviate water resource shortages, and this can be achieved through a high-energy-efficient forward osmosis (FO) process combined with an emerging material, zeolitic imidazolate framework-8 (ZIF-8). Here, we create thin-film composite FO membranes (TF-CFOMs) by incorporating ZIF-8 into the active polyamide (PA) and/or support polysulfone (PSf) layers to address the challenges of low water flux and loss of draw solutes during operation. Experimental factors included the dosage of ZIF-8 nanoparticles in PA preparation solutions and the dosages of 2-methylimidazole (2-Hmim) and zinc nitrate hexahydrate (ZNH) in n-methyl-2-pyrrolidone (NMP) to fabricate the PSf casting solutions with in-situ formed ZIF-8 nanoparticles. Successful ZIF-8 incorporation on the TF-CFOM surface was confirmed, and the ZIF-8 TF-CFOMs exhibited increased surface hydrophilicity and separation performance. Only modifying the PA layer by adding 0.025 wt% ZIF-8 nanoparticles in trimesoyl chloride (TMC) resulted in the membrane (PA0.025T-PSf0) with water flux 2.3 times higher than the pristine TF-CFOM (4.9 LMH). The pristine and modified TF-CFOMs were further applied for aquaculture wastewater (AWW) recovery and removal of pharmaceuticals and personal care products (PPCPs). Results of water recovery demonstrated that the recovery rate reached 89.1% in 3.5 days when using the dual-layer modified TF-CFOM. Results of PPCP removal indicated that both pristine and modified TF-CFOMs can achieve high PPCP rejection efficiency (>90%), with the modified TF-CFOM (PA0.025T-PSf2.0) performing the best. Overall, the PA0.025T-PSf2.0 TF-CFOM achieved high and stable separation efficiency in long-duration AWW recovery, making it well-suited for practical field applications.

Sustainable wastewater recovery system employing geothermal energy – Performance and feasibility study

In this study, a sustainable wastewater recovery system employing geothermal energy has been proposed. The efficiency of the suggested sustainable system has been simulated using heat transfer. Then, component-wise validation has been carried out with the existing data available in the literature wherever applicable and estimated an error of ± 8 %. The proposed sustainable system’s parametric and performance analyses have employed the developed vapor. From the parametric study, it is observed that hot spring temperatures have a significant influence on sustainable systems. Further, through performance investigation, it is understood that low dam/river/sea water temperatures and enhancing the water condenser effectiveness and flow rate ratio simultaneously improve the system performance. For different climatic regions of India, explored the feasible geothermal hotspots near dams/rivers/seawater and analyzed that among the hot and dry, hot and humid, composite and cold regions, the proposed sustainable system is best suitable at a composite region with a maximum possible water extraction/freshwater generation rate of 0.78 L/h for the given specifications and operating range. Moreover, it is assessed that hot spring temperature is the deciding factor for sustainable system performance in different climatic regions. Further, the current study can be used as a reference for understanding the phenomenon of potential geothermal hotspots for wastewater recovery in various climatic areas

Enhanced astronaut hygiene and mission efficiency: a novel approach to in-suit waste management and water recovery in spacewalks

Enhanced astronaut hygiene and mission efficiency: a novel approach to in-suit waste management and water recovery in spacewalks

Opinion: Differentiating Natural Threats and Hazards for Water and Wastewater Structures and Operations - Energetic Threats and Hazards for the Water Industry

A novel approach is presented to view, discern, and to redefine dangerous threats and hazards from natural events that can impact water and wastewater systems. The intent of this approach is to minimize ambiguity while enhancing preparedness and operational awareness of water and wastewater facilities, each vital for sustainable public health. This new approach recognizes potential and kinetic energy sources to differentiate between the threats and hazards generated by natural events, such as hurricanes, tornadoes or landslides, which can impact the steady-state operations of essential water and wastewater recovery facilities, associated infrastructure, plus endanger workers and exposed personnel. To support thisrethinking, absent in current literature searches, “energetic models” for anticipating latent, partial or total disruption of water and wastewater facilities and related management operations from naturally occurring events, such as a hurricane, tornado, or landslide, are presented. The proposed “energetic models” are atypical, yet they have practical value and encourage the rethinking and reimagining of threats and hazards used by water professionals and related fields and professions. The proposed models can be applied clearly to multiple and complex natural, human-caused, technological and equally disruptive events for water enterprises, expanding to similar challenges in public health responses to disease outbreaks.

Experimental study of biological wastewater recovery using microbial fuel cell and application of reliability and machine learning to predict the system behavior

Today, the water crisis has necessitated wastewater recovery management more than ever. With the advancement of technology and the emergence of microbial fuel cells (MFCs), wastewater treatment has become an exceptional opportunity for electricity production. In the present work, an experimental study has been carried out for the possibility of treating the wastewater of Borujerd textile factories in a period of ten days using an MFC. In order to save time and costs for experimental studies, the reliability analysis has been used to predict the behavior of fuel cells made in simple mode and multi-anode shared cathode mode. In addition, in order to evaluate the performance of MFCs that are made at the experimental level, deep learning has been used to extract comprehensive relationships. Finally, the economic and environmental evaluation of the simple and multi-anode shared cathode MFC has been done. The research results show that the COD removal efficiency in the system constructed for textile wastewater is 73 %, while the constructed fuel cell maximum power density is 281.5 mW/m2 from wastewater recycling. Reliability analysis of the studied system shows that adding anode to the MFC increases its operational life so for a fuel cell with 6-anodes, the life of the fuel cell increases by approximately 74 days. But in the design of an MFC, it is necessary to pay attention to the cost and emission of environmental pollutants, because the increase of the anode increases the costs and emission of environmental pollutants so that the built fuel cell will function in the most optimal way possible.

Bioelectrochemically altering microbial ecology in upflow anaerobic sludge blanket to enhance methanogenesis fed with high-sulfate methanolic wastewater

A bioelectrochemical upflow anaerobic sludge blanket (BE-UASB) was constructed and compared with the traditional UASB to investigate the role of bioelectrocatalysis in modulating methanogenesis and sulfidogensis involved within anaerobic treatment of high-sulfate methanolic wastewater (COD/SO42− ratio ≤ 2). Methane production rate for BE-UASB was 1.4 times higher than that of the single UASB, while SO42− removal stabilized at 16.7%. Bioelectrocatalysis selectively enriched key functional anaerobes and stimulated the secretion of extracellular polymeric substances, especially humic acids favoring electron transfer, thereby accelerating the electroactive biofilms development of electrodes. Methanomethylovorans was the dominant genus (35%) to directly convert methanol to CH4. Methanobacterium as CO2 electroreduction methane-producing archaea appeared only on electrodes. Acetobacterium exhibited anode-dependence, which provided acetate for sulfate-reducing bacteria (norank Syntrophobacteraceae and Desulfomicrobium) through synergistic coexistence. This study confirmed that BE-UASB regulated the microbial ecology to achieve efficient removal and energy recovery of high-sulfate methanolic wastewater.

Carbon flow, energy metabolic intensity and metagenomic characteristics of a Fe (III)-enhanced anerobic digestion system during treating swine wastewater

Deep treatment and bioenergy recovery of swine wastewater (SW) are beneficial for constructing a low-carbon footprint and resource-recycling society. In this study, Fe (III) addition from 0 to 600 mg/L significantly increased the methane (CH4) content of the recovered biogas from 61.4 ± 2.0 to 89.3 ± 2.0 % during SW treatment in an anaerobic membrane digestion system. The specific methane yields (SMY) also increased significantly from 0.20 ± 0.05 to 0.29 ± 0.02 L/g COD. Fe (III) and its bio-transformed products which participated in establishing direct interspecific electron transfer (DIET), upregulated the abundance of e-pili and Nicotinamide adenine dinucleotide (NADH), enriched electroactive bacteria. The increase in cellular adenosine triphosphate (cATP) from 6583 to 14,518 ng/gVSS and electron transport system (ETS) from 1468 to 1968 mg/(g·h) promoted the intensity of energy flow and electron flow during anaerobic digestion of SW. Moreover, Fe (III) promoted the hydrolysis and acidification of organic matters, and strengthened the acetoacetic methanogenesis pathway. This study established an approach for harvesting high quality bioenergy from SW and revealed the effects and mechanisms from the view of carbon flow, energy metabolic intensity and metagenomics.

Electrochemically assisted preparation of graphitic carbon nitride nanosheet membranes for efficient water purification

The development of a highly effective nanofiltration membrane for water purification is crucial for wastewater recovery. The graphitic carbon nitride (g-C3N4) membrane can be an ideal candidate for advanced water treatment due to its intrinsic porous structure and superior physicochemical stability. However, the developments of the g-C3N4 membranes are limited by their traditional preparation methods involving complicated processes, long reaction time and high-temperature conditions. A simple electrochemical-assisted strategy for the rapid preparation of the g-C3N4 nanosheet membranes at room temperature has been developed in this study. The ultra-thin g-C3N4 membrane with a uniform structure can be synthesized within 40 min, which is at least 7 times quicker compared to the traditional methods. The as-prepared g-C3N4 membrane shows a high water flux rate of ∼ 90 L m−2 h−1 bar−1. Simultaneously, an excellent rejection rate of 99.1% toward Evans blue is achieved based on the synergistic effect of size sieving and electrostatic repulsion. The breakthrough in the preparation method of g-C3N4 nanosheet membranes in this work is of great significance to the development of g-C3N4 membranes in the field of water purification.

Application and Mechanism of Lithium-ion Sieves in the Recovery of Lithium-Containing Wastewater: a Review

Application and Mechanism of Lithium-ion Sieves in the Recovery of Lithium-Containing Wastewater: a Review

Design of hydroponic wastewater recovery process for CO2, NOx, and NH3 utilization from crop residue burning gas

Design of hydroponic wastewater recovery process for CO2, NOx, and NH3 utilization from crop residue burning gas

Screening and performance optimization of fungi for heavy metal adsorption in electrolytes.

The resource recovery and reuse of precious metal-laden wastewater is widely recognized as crucial for sustainable development. Superalloy electrolytes, produced through the electrolysis of superalloy scrap, contain significant quantities of precious metal ions, thereby possessing substantial potential for recovery value. This study first explores the feasibility of utilizing fungi to treat Superalloy electrolytes. Five fungi resistant to high concentrations of heavy metals in electrolytes (mainly containing Co, Cr, Mo, Re, and Ni) were screened from the soil of a mining area to evaluate their adsorption characteristics. All five fungi were identified by ITS sequencing, and among them, Paecilomyces lilacinus showed the best adsorption performance for the five heavy metals; therefore, we conducted further research on its adsorption characteristics. The best adsorption effect of Co, Cr, Mo, Re, and Ni was 37.09, 64.41, 47.87, 41.59, and 25.38%, respectively, under the conditions of pH 5, time 1 h, dosage 26.67 g/L, temperature 25-30°C, and an initial metal concentration that was diluted fivefold in the electrolyte. The biosorption of Co, Mo, Re, and Ni was better matched by the Langmuir model than by the Freundlich model, while Cr displayed the opposite pattern, showing that the adsorption process of P. lilacinus for the five heavy metals is not a single adsorption mechanism, but may involve a multi-step adsorption process. The kinetics study showed that the quasi-second-order model fitted better than the quasi-first-order model, indicating that chemical adsorption was the main adsorption process of the five heavy metals in P. lilacinus. Fourier transform infrared spectroscopy revealed that the relevant active groups, i.e., hydroxyl (-OH), amino (-NH2), amide (- CONH2), carbonyl (-C = O), carboxyl (-COOH), and phosphate (PO43-), participated in the adsorption process. This study emphasized the potential application of P. lilacinus in the treatment of industrial wastewater with extremely complex background values.

Evaluating the environmental and economic performance of biological and advanced biological wastewater treatment plants by life cycle assessment and life cycle costing.

The primary objective of this study is to assess and establish benchmarks for environmental and economic sustainability of biological and advanced biological wastewater treatment plants (WWTPs) with different treatment technologies and characteristics. Furthermore, the study aims to determine the beneficial role of WWTPs to reduction of eutrophication potential. Environmental and economic sustainability of ten municipal WWTPs was assessed using life cycle assessment (LCA) and life cycle costing (LCC). In the first section of the study, LCA was performed to determine the environmental performance of the WWTPs. Furthermore, net environmental benefit (NEB) approach was implemented to reveal the beneficial role of WWTPs to eutrophication potential. In the subsequent section, LCA-based LCC was conducted by integrating the results of LCA. The most significant environmental impact was determined as marine aquatic ecotoxicity, which is highly affected from the generation and transmission of electricity consumed in the WWTPs. Wastewater recovery and co-incineration of sewage sludge in cement kiln ensure significant environmental savings on ozone layer depletion, human toxicity, acidification, photochemical oxidation, and abiotic depletion (fossil fuel) potential. Considering NEB approach, the highest NEB values were found for the WWTPs with the higher organic load and nutrient concentration in the influent. The results of LCC in WWTPs varied between 0.21 and 0.53 €/m3. External (environmental) costs were evaluated higher than internal (operational) costs for all selected WWTPs. While eutrophication was the highest among environmental costs, electricity cost was the highest among operational costs for almost all WWTPs.

Development of novel high anti-pollution polyamide/polysulfate disk tubular reverse osmosis membrane modules and their application in simulated space bathing wastewater

Water is a precious resource in space stations, and wastewater recycling is necessary to meet the needs of astronauts. In that respect, applying the high anti-pollution disk tubular reverse osmosis (DTRO) technique is a reliable way to remove pollutes from wastewater. Thin film composite (TFC) membrane treatment is the most frequently employed solution for purifying wastewater in industry; however, the intrinsic weaknesses of polymer membrane substrates, e.g., poor mechanical property, foulant adsorption and low resistance to acidic/basic conditions, greatly hamper their applications. In this study, the novel polysulfate (PSE) membrane substrates were prepared via non-solvent induced phase separation (NIPS) method. The microstructure and performance of PSE membrane substrates were comprehensively investigated at varying polymer concentration and nanoparticle types. The results showed that adding nanosilver to the support layer significantly enhanced the TFC- PSE/Ag membrane performance (up to 57 %) and tensile strength (by 4.57 ± 0.13). According to computational fluid dynamics (CFD) simulations, the optimized geometric design of deflectors would have noticeably improved the flow field distribution and strength, which was consistent with experimental data. The DTRO modules enabled the effective management of wastewater using simulated space bathing wastewater. The effluent met the water reuse criteria in terms of COD concentration, NH3-N concentration, conductivity and turbidity whose respective values were 15 mg/L, 0.21 mg/L, 60 μS/cm, and 0.9 NTU. The proposed DTRO modules own antifouling and acid/alkaline-resistance, indicating their remarkable application potential in the large-scale recovery of bathing wastewater from the earth or space station.

THE EFFECT OF IMMOBILIZED ENZYME ON TEXTILE WASTEWATER

Textile wastewater has a complex composition characterized by high dye content and chemical oxygen demand. Therefore, textile wastewaters have serious environmental impacts, such as aesthetic degradation, and carcinogenic properties. Treatment and the recovery of textile wastewater are important due to their high volume and toxicity. The effects of peroxidase enzyme immobilized on magnetic chitosan-clay beads of synthetic textile wastewater were investigated in a batch reactor. System performance was determined by chemical oxygen demand (COD) and color. The batch reactor was operated in three different pH (5, 7, 10), temperatures (25, 35, 45 °C), and reaction times (0-5-10-20-30 min.) with synthetic textile wastewater. As a result, COD and color removal efficiencies were determined as 44% and 56%, respectively, corresponding effluent concentrations are 1442 mg/L, 450 Pt-Co. The results of this study show that using the enzyme immobilization process is an effective method to remove color and COD concentration from textile wastewater.

Phosphorus-supplemented seawater–wastewater cyclic system for microalgal cultivation: Production of high-lipid and high-protein algae

The reuse of wastewater after seawater cultivation is critically important. In this study, a phosphorus-supplemented seawater–wastewater cyclic system (PSSWCS) based on Chlorella pyrenoidosa SDEC-35 was developed. With the addition of phosphorus, the algal biomass and the ability to assimilate nitrogen and carbon were improved. At the nitrogen to phosphorus ratio of 20:1, the biomass productivity per mass of nitrogen reached 3.6 g g−1 (N) day−1 in the second cycle. After the third cycle the protein content reached 35.7% of dry mass, and the major metabolic substances in PSSWCS reached the highest content level of 89.5% (35.7% protein, 38.3% lipid, and 15.5% carbohydrate). After the fourth cycle the lipid content maintained at 40.1%. Furthermore, 100.0% recovery of wastewater in PSSWCS increased the nitrogen and carbon absorption to 15.0 and 396.8 g per tonne of seawater. This study achieved seawater–wastewater recycle and produced high-lipid and high-protein algae by phosphorus addition.