Kind Of Wastewater Research Articles

Bioremediation of chromium(VI) and arsenic(III) using isolated microalgal (Chlorella thermophilia): Analysis of growth, biomolecular compositions (carbohydrate, protein, chlorophyll) and biosorption kinetics

Microalgae are under research focus for the production of bio-fuels by bioremediation of different kinds of wastewater like industry and municipality and other sources. The current study deals with investigations towards the capability of isolated microalgae (Chlorella thermophilia) for the removal of Cr(VI) and As(III) by re-modeling their extracellular and intracellular compositions. This isolated microalgae was able to grow in the presence of Cr(VI) up to 1 mg L−1 concentration and As(III) up to 15 mg L−1 concentration. Carbohydrate content in microalgae increased to 28 % in 0.4 mg L−1 of Cr(VI) and 46 % in 10 mg L−1 of As(III) respectively as compared to control. The protein content of Chlorella thermophilia grown in Cr(VI) [1 mg L−1] and As(III) [15 mg L−1] containing media decreased by almost 61 % and 9 % respectively as compared to control. Growth kinetics results revealed the decline in biomass to 10 % and 15 % under exposure of Cr(VI) [0.6 mg L−1] and As(III) [10 mg L−1] respectively compared to control. Chlorella thermophilia showed the removal of As(III) within the range of 70–91 % [at an As(III) concentration of 0.5–10 mg L−1], while removal of Cr(VI) was within 50–65 % [at a Cr(VI) concentration of 0.2–0.6 mg L−1]. Interestingly, almost 60 % of Cr(VI) was removed within 6 days of microalgae growth while removal of As(III) was slow and steadily increased to 80 % in 30 days. Our results showed the prospects of Chlorella thermophilia as a sustainable resource for the removal of heavy metals [Cr(VI) and As(III)] from wastewater. In addition, the enrichment of carbohydrates in microalgae during their growth would be supportive for the production of biofuels.

Detection and characterization of micro‐ and nano‐plastics in wastewater: Current status of preparatory & analytical techniques

AbstractMicro‐ and nano‐plastics (MNPs) are ubiquitous emerging pollutants that have gained global traction due to their persistent nature and potential risks to the environment and human health. The physico‐chemical properties of MNPs such as size, shape, density, surface charge and hydrophobicity are quite different from macro‐plastics, which render them unique behavior exemplified by high rate of diffusion, high mobility, easy uptake by organisms, high toxicity, and potential of bioaccumulation. Human exposure to MNPs causes serious health impacts including apoptosis, necrosis, inflammation, oxidative stress, metabolic disorders, and hampered immune responses. The hazardous nature and high persistence of MNPs in the environment necessitates accelerated studies focused upon their detection, quantification, impact analysis, and risk assessment. All kinds of wastewaters whether municipal, agricultural, or industrial, consist of significant loads of MNPs and act as secondary source of MNP pollution in groundwater and soil. Wastewater is highly complex in composition and there are several impediments in the accurate detection and identification of MNPs in this matrix owing to the in‐efficient sampling methods, lack of standardized methodologies, and non‐reproducibility of data. This review provides an overview of currently available techniques for sampling, detection, identification, and characterization of MNPs in wastewater. A critical commentary on the challenges and limitations of these techniques has been given and strategic combinatorial methods have been suggested for efficient and reliable MNP analysis in wastewater samples. The article also highlights novel sensor‐based methods enabling rapid and accurate detection of MNPs in wastewater.

Treatment of landfill leachate nanofiltration concentrate by a three-dimensional electrochemical technology with waste aluminum scraps as particle electrodes: Efficacy, mechanisms, and enhancement effect of subsequent electrocoagulation

Landfill leachate nanofiltration concentrate is a kind of wastewater containing high concentrations of color and refractory organics. Herein, we proposed a novel three-dimensional electrochemical technology (3DET) with waste aluminum scraps as particle electrodes for its treatment. The planar and particle electrodes were first optimized. Ti/RuO2 and graphite were used as anodes in the two-dimensional electrochemical technology (2DET). In the light of contaminant removal (color, UV254, COD, and TOC), chlorine reduction, and energy consumption, graphite was selected as planar anodes and cathodes. Moreover, 3DET with Al particle electrodes (Al 3DET) outperformed that with conventional granular activated carbon electrodes, 2DET, and Al particles. At 120 min, the removal efficiencies of color, UV254, COD, and TOC using Al 3DET were 98.94 %, 84.72 %, 51.93 %, and 67.46 %, respectively. UV–vis and EEM spectroscopy, and GC–MS analyses indicate that macromolecular organic matter such as humic-like substances could be effectively degraded and simultaneously removed. Reactive species identification tests including free radical quenching and EPR spectra were conducted. The results indicate that in addition to anodic direct oxidation, indirect oxidation by oxidative species (H2O2, •OH, and RCS) and flocculation by Al species also played a vital role in contaminant removal. Continuous-flow experiments show that Fe EC as a post-treatment step of Al 3DET could effectively provide a neutralization effect for the 3DET effluent and enhance the removal efficiency of contaminants. The total operating cost of combined process was 1.307 USD/m3. This study shows that the Al 3DET-Fe EC process is a promising technology for the treatment of nanofiltration concentrate.

Biochar-Based Adsorbents for Pesticides, Drugs, Phosphorus, and Heavy Metal Removal from Polluted Water

Water contamination is a ubiquitous issue for all countries and territories worldwide. Among others, pesticides, drugs, heavy metals, and phosphates play a special role in terms of pollutants due to their toxicity and large-scale applications in industrial and agricultural activities. In order to provide cleaner freshwater for the world’s population, two types of actions are required: preventing/limiting the pollution that might occur during our daily activities and decontaminating the already exposed/contaminated water sources. One of the key points in the decontamination process is to create as few as possible side effects with the solutions applied. For this reason, in the case of the mentioned types of pollutants but not limited only to them, the use of environmentally friendly materials is more than welcome. Biochar qualifies as one of these materials, and its field of applications expands to larger scientific and industrial areas every day. Moreover, it can be functionalized in order to improve its properties in terms of pollutant removal efficiency. This paper summarizes the most recent developments in the field of water decontamination using biochar or biochar-based materials in order to remove pesticides, drugs, heavy metals, and phosphates from contaminated aqueous environments. Also, the removal of phosphorus from wastewater using biochar is considered. This removal can be a key controlling factor for the wastewater, which is obtained as a residual of agricultural activities. Indeed, due to the excessive use of chemical fertilizers, eutrophication in such kinds of wastewater can be a serious challenge.

A simple method to prepare carbon-based mesoporous materials by coal gasification of fine slag and its application in phenol adsorption

Phenol is a common organic pollutant that is difficult to degrade and widely exists in all kinds of wastewater. In this study, an economical and environmentally friendly alternative process for phenol-containing wastewater has been developed using porous nano-adsorption material (PNAM) prepared from coal gasification fine slag. The morphology, crystal structure, surface functional groups, gap structure, and specific surface area of PNAM were characterized by SEM, XRD, FT-IR, and BET. The effects of adsorbent dosage, temperature, pH, and reaction time on adsorption were further investigated. In addition, the adsorption kinetics, thermodynamics, and adsorption mechanism were explored. The results show that the surface area of PNAM is high, up to 602 m2 g−1, and the pore volume is 0.507 cm3 g−1. Adsorption processes mainly occur in mesopores between 2 and 5 nm, including physical and chemical adsorption, and here chemical adsorption plays a significant role. The adsorption rate of phenol in a 1000 mg l−1 simulated phenol solution by PNAM reaches 96.14%, while the unit adsorption capacity is 32.045 mg g−1. As a result, it is expected that employing coal gasification fine slag to prepare adsorption materials for phenol-containing wastewater treatment may be an economically feasible and environmentally sustainable strategy.

A comparative study on the inhibitory effects imposed on earthworms by brewery and rice mill wastewater

Of late, vermifiltration (VF) technology has gained major attention from researchers as a sustainable wastewater treatment alternative in which the treatment of wastewater has been driven by earthworms (EWs). Apart from parametric effects, the composition, biodegradability/complexity, hydraulic and organic loading rates (HLR/OLR), and the concentration of organics present in wastewater exhibit inhibitory effects on EWs, declining the treatment efficiency of vermifilters (VFs), which have not been adequately explored. Hence, the present study dealt with the assessment of such inhibitory effects on the survival, growth, and reproduction of EWs using four kinds of wastewater. Results indicated that EWs sustained the flow of rice mill, real brewery, synthetic brewery, and the mixture of real brewery and domestic wastewater for 5–11, 11–21, 20–40, and 23–45 d, respectively, before reaching 50% mortality, at the HLR of 8–4 m3/m2-d. For each wastewater, the lowest HLR (4 m3/m2-d) yielded the highest growth of EWs. The mixture of real brewery and domestic wastewater provided the most favorable conditions for the reproduction of EWs, ensuring the highest number of cocoons (8–12 nos./EW) and juveniles (11–26 nos./EW) produced per EW, followed by synthetic brewery (cocoon: 3–9 nos./EW; juvenile: 5–18 nos./EW), real brewery (cocoon: 2–7 nos./EW; juvenile: 2–12 nos./EW), and rice mill wastewater (cocoon: 1–5 nos./EW; juvenile: 2–8 nos./EW), with the HLR varying inversely with the reproduction rate of EWs. Hence, the mixture of real brewery and domestic wastewater portrayed the least biological inhibition on EWs, whereas rice mill wastewater had the highest. Outcomes of the present study revealed that the VF technology is best suited for remediating the mixture of real brewery and domestic sewage, can substantially remediate synthetic brewery wastewater, and may treat real brewery and rice mill wastewater after an appropriate pretreatment. The premixing of real brewery wastewater with rapidly biodegradable and low-strength domestic sewage at a specific volumetric ratio improved the treatability of the former using the VF technology attributed to the enhanced biodegradability and reduced organic strength of the wastewater mix.

Evaluation of Seasonal a Spatial Variation of Groundwater Quality by Determining Factors Associated with Water Quality Using Multivariate Analytical Methods, Erbil Central Sub-Basin

The study area is located in the northern Iraqi province of Erbil, covering a total area of about 1400 Km2 (3.5% of Iraq). The Erbil basin is mostly covered by Quaternary sediments, with only a few outcrops of Miocene–Pliocene formations in the east and northeast of Sharabot-Dedawan highlands, Avanah Mountain in the west and southwest in narrow strips, and Damirdagh in the north. The lithology of sediments ranges from clay, silt, sand, and gravel (sandstone, clay stone, and conglomerate). Erbil Basin, also known as Dashty Hawler Basin, Erbil provinces is the largest groundwater reservoir, with a surface area of 3200 Km2 and a depth of approximately 800 meters. Erbil Basin, one of the Middle East's most important groundwater basins, is bounded on the north by the Greater Zab River and on the south by the Lesser Zab River. Thirty water samples (27 samples of groundwater wells, and 3 samples of wastewater channels) were collected during May (Water surplus period) and September (Water deficit period) 2020 in Erbil central sub-basin and analyzed. Physical analyses include temperature (T), pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Biological Oxygen Demand (BOD5), Chemical oxygen demand (COD), Dissolved oxygen (DO), Total Suspension sediments (TSS), whereas the geochemical analysis included concentration determination of the major, minor and trace elements. This article aims to evaluate the pollution in groundwater of the Erbil central sub-basin due to different kinds of wastewater, the samples of water in the study area were collected from different locations and sources, deep wells, and waste. all chemical, physical, and trace elements parameters are presented in this work, the pollution has been founded in the study area due to waste water by Kahrez (old groundwater distribution in Erbil basin), cesspools, and septic tanks.

Using quantum chemistry theory to elucidate the mechanism for treating sulfonamide antibiotic wastewater by progressive freezing

Progressive freezing is a separation and purification technology that is widely used to treat various kinds of wastewater because of providing energy savings and environmental protection. However, there have been no reports of using it to treat sulfonamide antibiotics (SAs) wastewater and the mechanism of the progressive freezing method for wastewater treatment still needs to be clarified. Therefore, we selected four typical SAs, including sulfadiazine (SD), sulfapyridine (SP), sulfamethazine (SM2) and sulfaquinoxaline (SQ), as research subjects to systematically explore the solid–liquid phase distribution of SAs during the freezing process. We considered the binding energy between an SA and an ice molecule or a water cluster to elucidate the purification mechanism of the freezing process. The results showed that the purification rate of the SAs solution was 65 %–86 % and decreased in the order SD > SP > SM2 > SQ. The Gaussian calculation showed that the binding energy of SAs to the ice phase was less than that to the water phase, resulting in the separation of the SAs in ice-water two-phase and purification of the ice body. The main reason for the difference among the purification rates of the four SAs during the progressive freezing process was the difference in the binding energies of the SAs to the ice-water two-phase.

Safe Reuse of Wastewater: Organic Contaminants Degradation and Sanitization by Ozone in a Modulable Continuous-Flow System

Effective treatments improving both the chemical and microbiological quality of reclaimed wastewater are urgently needed. Ozone is a clean, economic, and environmentally friendly method to sanitize solutions and surfaces and to degrade organic pollutants. A simple, continuous-flow water-ozoniser system was tested to evaluate its effectiveness in batch treating various kinds of wastewater, including the effluent from small municipal plants. The degradation effects on a mixture of urban and industrial standard pollutants were investigated by HPLC-UV-MS analysis and biotoxicological assays. The results revealed that the concentration of most organic pollutants was reduced to 20–0% of the initial one within one hour. One resultant compound was recalcitrant (40% reduction only). The bioassays indicated the definitive reduction in toxic effects after treatment. Similar results were obtained when secondary, post sedimentation, wastewater treatment plant effluents were treated. Heterotrophic plate counts confirmed the strong biocidal activity of ozone. The developed prototype can successfully treat locally produced wastewater, secondary effluents from small–medium plants, and non-potable water resources.

Aluminium carbide nano-sheet as a promising adsorbent for removal of carbendazim

• Adsorbent efficacy of aluminium carbide nano-sheet (AlC 3 NS) for CB was evaluated for the first time. • CB interacted with the Al atoms of AlC 3 NS via -C=O group and the adsorption energy was approximately −30.14 kcal/mol. • The HOMO-LUMO analysis was conducted for investigating the charge transfer process. The widespread use of carbendazim (CB) as a pesticide molecule to control pests and to protect crops has worsened the problems associated with pollution. The excessive use of CB can cause atmospheric pollution through the contamination of soil as well as water sources. Within the current work, the adsorbent efficacy of aluminium carbide nano-sheet (AlC 3 NS) for CB was evaluated for the first time. We evaluated some of the important properties of CB, AlC 3 NS, and complex of CB-AlC 3 NS for investigating the effectiveness of AlC 3 NS as an adsorbent system. CB interacted with the Al atoms of AlC 3 NS via -C=O group and the adsorption energy was approximately −30.14 kcal/mol. The HOMO-LUMO analysis was conducted for investigating the charge transfer process, which was further supported by NBO analysis. The results demonstrated the possibility of using the AlC 3 NS as an efficient adsorbent system for the CB for the treatment of different kinds of wastewater.

Simultaneous nitrogen and sulfur removal using Anammox coupled sulfide-denitrification process: Impact of pH

Nitrogen and sulfur coexisted in many kinds of wastewaters, which could be simultaneously removed in the Anammox coupled sulfide-denitrification process. In this study, the pH suitable for the coupling process was analyzed in a biofilter. The results showed that the coupling process could operate normally at pH of 6.5–8.5, with the total nitrogen removal efficiency (TNRE) higher than 85.0 %. At pH 7.5, the TNRE reached the highest, the hydroxylamine oxidoreductase (HAO) activity and heme-c reached 0.998 EU·g−1 SS and 0.0010 mmol·g−1 SS, respectively, with the hzo and nosZ gene concentrations as 4.6 × 108 and 9.7 × 107 copies·mL−1. At pH 6.0, the process was significantly deteriorated and it secreted more protein to resist the pH shock, the TNRE was 34.0 %, HAO, hzo and nosZ genes and abundance of Candidatus_Kuenenia decreased by 2.8, 4.2, 2.2, and 1.4 times, respectively. Thiobacillus reduced nitrate to nitrite and supplied for Candidatus_Kuenenia, but utilized nitrite in adverse environment.

Review: Wastewater Treatment in Different Industries

Abstract: Wastewater treatment is a process used to remove contaminants from wastewater and convert it into an effluent that can be returned to the water cycle. Once returned to the water cycle, the effluent creates an acceptable impact on the environment or is reused for various purposes (called water reclamation). The treatment process takes place in a wastewater treatment plant. There are several kinds of wastewater which are treated at the appropriate type of wastewater treatment plant. For domestic wastewater (also called municipal wastewater or sewage), the treatment plant is called a sewage treatment plant. For industrial wastewater, treatment either takes place in a separate industrial wastewater treatment plant, or in a sewage treatment plant (usually after some form of pre-treatment). Further types of wastewater treatment plants include agricultural wastewater treatment plants and leachate treatment plants. Processes commonly used in wastewater treatment include phase separation (such as sedimentation), biological and chemical processes (such as oxidation) or polishing. The main by-product from wastewater treatment plants is a type of sludge which is usually treated in the same or another wastewater treatment plant. Biogas can be another by-product if anaerobic treatment processes are used. Treated wastewater can be reused as reclaimed water. The main purpose of wastewater treatment is for the treated wastewater to be able to be disposed or reused safely. However, before it is treated, the options for disposal or reuse must be considered so the correct treatment process is used on the wastewater. Performance ofstate owned sewage treatment plants, for treating municipal waste water, and common effluent treatment plants, for treating effluent from small scale industries, is also not complying with prescribed standards. Thus, effluent from the treatment plants, often, not suitable for household purpose and reuse of the waste water is mostly restricted to agricultural and industrial purposes. The development of innovative technologies for treatment of wastewaters from various industries isa matter of alarming concern for us. Although many research papers have been reported on wastewater pollution control studies, but a very few research work is carried out for treatment of wastewater of steel industries, especially in reference to development ofdesign of industrial effluent Treatment Plants (ETP)system. Another beneficial aspect of this research work will be recycling, reuse of water and sludge from steel industry The whole technologies for treating industrial wastewater can be divided into four categories: - Chemical, Physical, Biological and mathematical approaches.

Towards biomass production and wastewater treatment by enhancing the microalgae-based nutrients recovery from liquid digestate in an innovative photobioreactor integrated with dialysis bag

Microalgae-based nutrients recovery from liquid anaerobic digestate of swine manure has been a hotspot in recent decades. Nevertheless, in consideration of the high NH4+-N content and poor light penetrability exhibited by the original liquid digestate, uneconomical pretreatment on liquid digestate including centrifugation and dilution are indispensable before microalgae cells inoculation. Herein, aiming at eliminating the energy-intensive and freshwater-consuming pretreatment on liquid digestate and enhancing microalgae growth, the dialysis bag which permits nutrients transferring across its wall surface whereas retains almost all matters characterized by impeding light transmission within the raw liquid digestate was integrated into a column photobioreactor (DB-PBR). Consequently, light availability of microalgae cells in DB-PBR was elevated remarkably and thus contributed to a 357.58% improvement on microalgae biomass concentration in DB-PBR than the conventional PBR under 80 μmol m−2 s−1. Likewise, superior nutrients removal efficiencies from liquid digestate were obtained in DB-PBR (NH4+-N: 74.84%, TP: 63.75%) over the conventional PBR (NH4+-N: 30.27%, TP: 16.86%). Furthermore, higher microalgae biomass concentration (1.87 g L−1) and nutrients removal efficiencies (NH4+-N: 95.12%, TP: 76.87%) were achieved in the DB-PBR by increasing the light intensity to 140 μmol m−2 s−1. More importantly, the DB-PBR may provide a simple and greener solution to purify other kinds of wastewater.

A New Approach to Single Chambered Microbial Fuel Cell for Procreation of Bioenergy in the Treatment of Sugar and Dairy Wastewater

Pollution of water, waste disposal, and their management is big problem faced by the world today. Industrial waste, agricultural waste, and household waste are best substrates for energy generation. India is one of the leading producers of sugar and dairy products in the world. These industries discharge a bulk amount of wastewater per day without proper treatment during working seasons. Sugar and dairy industry wastewater has high COD and BOD, which is hazardous for aquatic life and human use also. MFC have earned importance in the last few decades due to its ability to generate bioelectricity from all renewable sources, Most of the MFCs have been used to treat different kinds of wastewater, such as sugar, dairy, brewery, domestic wastewater, distillery, rice mill, paper and pulp, swine wastewater, etc.

Membrane distillation combined with electrocoagulation and electrooxidation for the treatment of landfill leachate concentrate

The landfill leachate concentrate is a kind of waste water containing salt and refractory organics produced by the membrane bioreactor-nanofiltration/reverse osmosis process. In the present work, three integrated processes of electrocoagulation (EC)-direct contact membrane distillation (DCMD), electrooxidation (EO)-DCMD and EC-EO-DCMD were used to treat the leachate concentrate. The results show that the total organic carbon (TOC), Ca2+ and Mg2+ removal rates of the EC process were 40.52%, 98.03% and 88.84%, respectively, under the optimal operating conditions. The TOC removal rate of the EO process was 64.62% under the optimal operating conditions. The removal rates of TOC, Ca2+ and Mg2+ by combined EC-EO process were 82.16%, 99.04% and 94.22%, respectively. When the MD was applied together with the EC and EO steps, the flux improved 23%∼42%, which was confirmed by the SEM-EDS, FTIR and XRD analysis that only quite a small amount of humic acid and fulvic acid substances was observed to be randomly deposited on the membrane surface. During 72 h operation, the permeate had a lower conductivity than 15 μS/cm, and only a small amount of organic (TOC < 9.6 mg/L) was detected. These results clearly demonstrated that the EC and EO processes can effectively reduce the refractory organics and scaling inorganics, and coupled with MD can synergistically to remove the pollutant that providing a better choice for the treatment of leachate concentrate.

Biochar for wastewater treatment – a Minireview**

Wastewater must be treated no matter if is reused or discharged into the environment. The cost of wastewater treatment may be rather high, though other solutions are sought. One of them is the application of filter materials. The filter materials have been used for removal of various pollutants in different kinds of wastewater and a wide range of filter materials (natural products, industrial waste products or man-made products) have been investigated. Among these filter materials, biochar has attracted increasing attention during the last decade. A large number of publications are devoted to production, properties and potential applications of biochar. They reveal that biochar is capable of removing pollutants of different kinds from wastewaters.&#x0D; A number of experiments was focused on the removal of commonly found pollutants, e.g. nutrients, heavy metals, organic matters and pharmaceuticals. It was found that the origin of the feedstock and the thermochemical treatment method are tightly connected and will have an impact on the properties of the biochar. A large number of different feedstock material like wood or wood residues, garden wastes or human and animal wastes can be transformed into biochar by torrefaction and pyrolysis. Properties of biochar will depend on transformation method. Surface area, porosity, pH, surface charge, functional groups and mineral components contribute to a vast number of mechanisms that are responsible for the metal removal, e.g. electrostatic interaction between the surface of the biochar and the specific metal, the cation exchange capacity between metals and protons and the alkaline metals on the surface of the biochar, metal complexation with functional groups and precipitation of metals that form non-soluble compounds. Biochar was successfully applied in wetlands systems to increase the removal of some targeted pollutants.

Leachate from municipal solid waste landfills in a global perspective: Characteristics, influential factors and environmental risks

Landfilling is one of the most common measures for disposing municipal solid waste, while the environmental leakage of landfill leachate, a kind of wastewater with complex compositions and high-level pollutants, has become a crucial eco-environmental issue all over the world. Understanding the profiles of landfill leachate can be useful for promoting sustainable municipal solid waste management, however, there are very few studies at a global level because of data insufficiency. In this work, we established a global database on the physicochemical characteristics of landfill leachate from academic literature, including 1251 pieces of data from 236 provinces or cities in 51 countries. Concentrations of typical pollutants in landfill leachate were aggregated by different categories of countries, climate zones, and landfill ages. Correlations between typical leachate pollutants (chemical oxygen demand, biochemical oxygen demand after five days, ammonia nitrogen, sulfate, chloridion, potassium, cadmium, chromium, ferrum, nickel, and lead) and their influential factors (mean annual temperature, mean annual precipitation, landfill age, and the fraction of food waste) were analysed; and the environmental risks led by landfill leachate were assessed. Results showed that: (1) landfill leachate in developing countries at the dry temperature zone, as well as the moist and wet tropical zone, contained higher concentrations of chemical oxygen demand and biochemical oxygen demand after five days; (2) the percentage of food waste, as an influential factor, has a positive correlation with typical landfill leachate pollutants, with R2 varying from 0.07 to 0.18, indicating its high potential on transforming organic fraction in solid waste into leachate; (3) In regard to the environmental risk resulted from landfill leachate, the groundwater and surface water had greater risks than soil environment nearby the landfill. Besides, chemical oxygen demand, ammonia nitrogen, ferrum, chloridion and heavy metals, especially arsenic, cadmium, nickel, and manganese were dominating pollutants in groundwater and surface water. This work provides valuable data and parameters of global landfill leachate, which could be helpful to mitigate pollution from landfills and achieve the goals of sustainable municipal solid waste management.

Chemical Cleaning-Triggered Release of Dissolved Organic Matter from a Sludge Suspension in a Ceramic Membrane Bioreactor: A Potential Membrane Foulant

Ceramic membrane bioreactors (MBRs) have attracted a great deal of interest due to their robustness in the treatment of various kinds of wastewaters. So far, in situ chemical cleaning with sodium hypochlorite (NaClO) has been the most prevalent MBR cleaning method. This study showed that in situ NaClO cleaning in MBRs triggered a significant release of dissolved organic matter (DOM) from a sludge suspension, while the generated DOM could facilitate fouling development, especially irreversible fouling in a ceramic MBR. It was found that biopolymers with a molecular weight (MW) of >10 kDa and humic substances could be effectively rejected by the ceramic membranes. As such, the membrane fouling rate (dTMP/dt) of the supernatant from a NaClO-treated sludge suspension was closely related to the rejected levels of biopolymers and humic substances. However, hydrophobic DOM and low-MW organics (MW < 500 Da) could easily pass through the membranes, indicating an insignificant contribution to the observed membrane fouling. Consequently, this study verified the contributions of DOM released from a sludge suspension after in situ membrane cleaning with NaClO with respect to subsequent membrane fouling development in a ceramic MBR.

A Comparative Study of Scenedesmus dimorphus Cultured with Synthetic and Actual Wastewater

This study compared the growth of the microalgae Scenedesmus dimorphus in synthetic wastewater and actual wastewater under different cultivation conditions, in terms of nitrogen and phosphorus availability, wastewater quality, light condition and CO2 addition. The results show that the form of nitrogen source had a significant effect on the growth of microalgae. Urea as a nitrogen source increased the growth rate of S. dimorphus significantly, while the high concentration of inorganic nitrogen inhibited the growth. When phosphate was 4 mg/L and pH was 7, the growth of S. dimorphus was the greatest. The bacteria in actual wastewater not only promote the growth of microalgae but also facilitate the formation of flocs, which is conducive to biomass harvest. With the increase in light intensity and light duration, S. dimorphus showed primarily an increasing and then a decreasing trend. Higher light intensity was required in actual wastewater than in synthetic wastewater, which may be due to the barrier effect of wastewater turbidity. S. dimorphus grew well in both kinds of wastewater with the addition of 2% CO2.

Effect of electrode configuration and voltage variations on electrocoagulation process in phosphate removal of laundry wastewater

Indonesia is one of the countries that still have to deal with waste problems. In reducing waste, the government has made a series of efforts to reduce waste, especially wastewater. There are many kinds of wastewater. One of them is laundry wastewater. This research aims to estimate the dangerous substance in laundry wastewater and how to treat it. The method using some variables like Al-Al, Al-Fe, Fe-Fe, and Fe-Al and the voltage is changing from 20 V, 30 V, 40 V, and 60 V. The research shows that the most optimum result of laundry wastewater treatment was using Al-Fe electrode plate 60 V. The result that the phosphate concentration decreased by 6.56 mg/l from 9.58 mg/l to 3.01 mg/l and obtained phosphate removal efficiency of 68.56%. The most optimum results for the removal of phosphate levels contained in the 60 V voltage.