scholarly journals Degradation of Landfill Leachate Using UV-TiO2 Photocatalysis Combination with Aged Waste Reactors

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 946
Author(s):  
Chunlian Wang ◽  
Xiaojie Sun ◽  
Huijun Shan ◽  
Hongxia Zhang ◽  
Beidou Xi
Keyword(s):  
Tio2 Nanoparticles ◽  
Landfill Leachate ◽  
Control Method ◽  
Irradiation Time ◽  
Combined Treatment ◽  
Oxygen Demand ◽  
Infrared Spectrometry ◽  
Process Conditions ◽  
Optimal Process ◽  
Removal Rates

This study explored the performance of TiO2 nanoparticles in combination with aged waste reactors to treat landfill leachate. The optimum conditions for synthesis of TiO2 were determined by a series of characterizations and removal rates of methyl orange. The effect of the ultraviolet irradiation time, amount of the catalyst, and pH on the removal efficiency for the chemical oxygen demand (COD) and color in the leachate was explored to determine the optimal process conditions, which were 500 min, 4 g/L and 8.88, respectively. The removal rates for COD and chroma under three optimal conditions were obtained by the single factor control method: 89% and 70%; 95.56% and 70%; and 85% and 87.5%, respectively. Under optimal process conditions, the overall average removal rates for ammonium nitrogen (NH4+–N) and COD in the leachate for the combination of TiO2 nanoparticles and an aged waste reactor were 98.8% and 32.5%, respectively, and the nitrate (NO3−–N) and nitrite nitrogen (NO2–N) concentrations were maintained at 7–9 and 0.01–0.017 mg/L, respectively. TiO2 nanoparticles before and after the photocatalytic reaction were characterized by emission scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and Fourier transform infrared spectrometry. In addition, TiO2 nanoparticles have excellent recyclability, showing the potential of the photocatalytic/biological combined treatment of landfill leachate. This simulation of photocatalysis-landfilling could be a baseline study for the implementation of technology at the pilot scale.

scholarly journals Treatment of landfill leachate with different techniques: an overview

2020 ◽  
Author(s):  
Amin Mojiri ◽  
John L. Zhou ◽  
Harsha Ratnaweera ◽  
Akiyoshi Ohashi ◽  
Noriatsu Ozaki ◽  
...  
Keyword(s):  
Landfill Leachate ◽  
High Performance ◽  
Membrane Filtration ◽  
Combined Treatment ◽  
Oxygen Demand ◽  
Ammonium Oxidation ◽  
High Chemical ◽  
Treatment Techniques ◽  
High Chemical Oxygen Demand ◽  
Biological Methods

Abstract Landfill leachate is characterised by high chemical and biological oxygen demand and generally consists of undesirable substances such as organic and inorganic contaminants. Landfill leachate may differ depending on the content and age of landfill contents, the degradation procedure, climate and hydrological conditions. We aimed to explain the characteristics of landfill leachate and define the practicality of using different techniques for treating landfill leachate. Different treatments comprising biological methods (e.g. bioreactors, bioremediation and phytoremediation) and physicochemical approaches (e.g. advanced oxidation processes, adsorption, coagulation/flocculation and membrane filtration) were investigated in this study. Membrane bioreactors and integrated biological techniques, including integrated anaerobic ammonium oxidation and nitrification/denitrification processes, have demonstrated high performance in ammonia and nitrogen elimination, with a removal effectiveness of more than 90%. Moreover, improved elimination efficiency for suspended solids and turbidity has been achieved by coagulation/flocculation techniques. In addition, improved elimination of metals can be attained by combining different treatment techniques, with a removal effectiveness of 40–100%. Furthermore, combined treatment techniques for treating landfill leachate, owing to its high chemical oxygen demand and concentrations of ammonia and low biodegradability, have been reported with good performance. However, further study is necessary to enhance treatment methods to achieve maximum removal efficiency.

Optimization of Microwave Roasting for Dechlorination of CuCl Residue under Oxygen-Enriched Condition

2016 ◽  
Vol 35 (2) ◽  
pp. 135-143 ◽  
Author(s):  
Guo Zhanyong ◽  
Ju Shaohua ◽  
Peng Jinhui ◽  
Zhang Libo ◽  
Lei Ting
Keyword(s):  
Oxygen Consumption ◽  
New Technology ◽  
Oxygen Demand ◽  
Polynomial Equation ◽  
Process Conditions ◽  
X Ray Diffraction ◽  
Optimal Process ◽  
Valuable Metals ◽  
Effects Of Temperature ◽  
Zinc Hydrometallurgy

AbstractThe clean utilization of the residue containing chloride, such as zinc oxide dust and CuCl residue, produced from zinc hydrometallurgy is very important for the recycle of valuable metals. In this paper, a new technology for dechlorination of the CuCl residue through thermal treatment with application of microwave and oxygen-enriched air roasting is brought out. And the response surface methodology (RSM) based on five-level, three-variable and central composite design (CCD) was used to optimize the operation parameters for increasing the dechlorination efficiency. The effects of temperature, roasting time and oxygen consumption on the dechlorination efficiency were studied and the optimal process conditions were identified. In addition, X-ray diffraction (XRD), scanning electron microscope (SEM) and Raman spectroscopy were used to characterize the dechlorination process under the optimum condition. The results showed that the experimental data were fitted to a second-order polynomial equation. The optimized process conditions are identified to be a roasting temperature of 451℃, heating duration of 114 min and oxygen consumption of 2.4 times the theoretical oxygen demand. A dechlorination efficiency of 96.4% could be achieved at the optimal process conditions.

Concentrated Landfill Leachate Treatment by Electro-Ozonation

2019 ◽  
pp. 150-170 ◽  
Author(s):  
Amin Mojiri ◽  
Lou Ziyang ◽  
Wang Hui ◽  
Ali Gholami
Keyword(s):  
Landfill Leachate ◽  
Combined Treatment ◽  
Oxygen Demand ◽  
Treatment Technique ◽  
Leachate Treatment ◽  
Primary Methods ◽  
Membrane Processes ◽  
Treatment Processes ◽  
The World ◽  
Pressure Driven

Municipal solid waste has continued to be a major problem in many nations of the world. The primary methods of treating landfill leachate include physical-chemical and biological treatment processes. Pressure-driven membrane processes, such as microfiltration, ultrafiltration, nanofiltration, and reverse osmosis (RO), are among the utmost promising and capable ways for treating landfill leachate. The concentrated leachate created from pressure-driven membrane processes typically represents 13%–30% of total incoming landfill leachate. Concentrated leachate is a dark brown solution with high levels of pollutants. Treating concentrated leachate is extremely difficult, and thus, a combined treatment system is suggested. In the present study, concentrated landfill leachate was treated using a combined treatment technique that included electro-ozonation. The removal efficacies of chemical oxygen demand (COD), color, and nickel were monitored at original pH (7.3) as well as current and voltage of 4 A and 9 V, respectively.

Evaluation of a chemical dissolved air flotation system for the treatment of restaurant dishwasher effluent

2013 ◽  
Vol 40 (12) ◽  
pp. 1164-1172 ◽  
Author(s):  
Wayne Chung ◽  
Stephanie Young
Keyword(s):  
Oxygen Demand ◽  
Process Conditions ◽  
Optimal Process ◽  
Oil And Grease ◽  
Nitrogen And Phosphorus ◽  
Dissolved Air Flotation ◽  
Treated Effluent ◽  
Removal Efficiencies ◽  
Air Flotation ◽  
Dissolved Air

Restaurant dishwashers consume a large quantity of fresh water and produce significant amounts of high strength oily wastewater which may cause serious problems when discharged into the sewer. An analysis of restaurant dishwasher effluent (RDE) from a busy upscale restaurant identified high levels of oil and grease, chemical oxygen demand (COD), biochemical oxygen demand (BOD), alkalinity, pH, and chlorine, but low levels of nitrogen and phosphorus. In this study, RDE was treated using an internationally patented chemical dissolved air flotation (chemical DAF) system. The chemical DAF system was designed so that coagulation, flocculation, and flotation processes could be carried out within the same reactor. The treatment system is therefore small and compact and suitable for use in restaurants where space is limited. The treatment performance of the chemical DAF was evaluated by determining optimal process conditions, contaminant removal efficiencies, and residual contaminant concentrations. It was found that removal efficiencies of 98.90%, 93.16%, 98.68%, 90.04%, and 88.20% could be achieved under optimal process conditions for turbidity, oil, TSS, BOD5, and COD, respectively. Total coliform and E. coli were not detected in either the raw dishwasher effluent or the treated dishwasher effluent due to the use of sodium hypochlorite as a dishwashing sanitizer. Water quality of the treated effluent met the criteria put forth in the Canadian Guidelines for Domestic Reclaimed Water for Use in Toilet and Urinal Flushing, with the exception of BOD5. Present findings suggest that chemical DAF is a promising treatment process for the removal of contaminants from restaurant dishwasher effluent.

Treatment of a complex landfill leachate with peat

1978 ◽  
Vol 5 (1) ◽  
pp. 83-97 ◽  
Author(s):  
Robert D. Cameron
Keyword(s):  
Chemical Oxygen Demand ◽  
Ferric Chloride ◽  
Landfill Leachate ◽  
Metal Removal ◽  
Oxygen Demand ◽  
Treatment Method ◽  
Manganese Concentration ◽  
Chemical Pretreatment ◽  
Iron Manganese

The use of cheap, locally available peat as a treatment method for landfill leachate was investigated by passing leachate through plexiglass columns filled with an amorphous-granular peat. Preliminary adjustment of pH showed that reducing pH to 4.8 dramatically reduced adsorption. Increasing the pH to 8.4, metal removal was increased owing to filtration of precipitated metals. The best adsorption of metals occurred at the 'natural' pH of 7.1. Manganese was found to be the limiting pollutant. At the 0.05 mg/ℓ maximum acceptable manganese concentration 94% of the total metals were removed, requiring 159 kg of peat per 1000 ℓ of leachate.Resting the peat for 1 month did significantly increase removal capacity.Desorption of some contaminants occurred when water was percolated through the peat. The desorption test effluent was not toxic to fish although iron, lead and COD (chemical oxygen demand) exceeded acceptable values.Chemical pretreatment using lime and ferric chloride achieved significant iron, manganese and calcium removals. Chemical pretreatment followed by peat adsorption offered no advantage other than reducing toxicity to fish.Peat treatment alone was effective in reducing concentrations to a level that was non-toxic to fish.

scholarly journals Enhanced Wastewater Treatment by Immobilized Enzymes

2021 ◽  
Author(s):  
Jakub Zdarta ◽  
Katarzyna Jankowska ◽  
Karolina Bachosz ◽  
Oliwia Degórska ◽  
Karolina Kaźmierczak ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Process Optimization ◽  
Organic Pollutants ◽  
Large Scale ◽  
Removal Rate ◽  
Immobilized Enzymes ◽  
Future Research ◽  
Process Conditions ◽  
Removal Rates ◽  
Catalytic Cycles

Abstract Purpose of Review In the presented review, we have summarized recent achievements on the use of immobilized oxidoreductases for biodegradation of hazardous organic pollutants including mainly dyes, pharmaceuticals, phenols, and bisphenols. In order to facilitate process optimization and achievement of high removal rates, effect of various process conditions on biodegradation has been highlighted and discussed. Recent Findings Current reports clearly show that immobilized oxidoreductases are capable of efficient conversion of organic pollutants, usually reaching over 90% of removal rate. Further, immobilized enzymes showed great recyclability potential, allowing their reuse in numerous of catalytic cycles. Summary Collected data clearly indicates immobilized oxidoreductases as an efficient biocatalytic tools for removal of hazardous phenolic compounds, making them a promising option for future water purification. Data shows, however, that both immobilization and biodegradation conditions affect conversion efficiency; therefore, process optimization is required to achieve high removal rates. Nevertheless, we have demonstrated future trends and highlighted several issues that have to be solved in the near-future research, to facilitate large-scale application of the immobilized oxidoreductases in wastewater treatment.

scholarly journals Treatment performances of French constructed wetlands: results from a database collected over the last 30 years

2015 ◽  
Vol 71 (9) ◽  
pp. 1333-1339 ◽  
Author(s):  
A. Morvannou ◽  
N. Forquet ◽  
S. Michel ◽  
S. Troesch ◽  
P. Molle
Keyword(s):  
Constructed Wetlands ◽  
Oxygen Demand ◽  
Pollutant Removal ◽  
Vertical Flow ◽  
Removal Rates ◽  
Waste Stabilization Ponds ◽  
Small Communities ◽  
Technical Department ◽  
In Series ◽  
High Chemical Oxygen Demand

Approximately 3,500 constructed wetlands (CWs) provide raw wastewater treatment in France for small communities (<5,000 people equivalent). Built during the past 30 years, most consist of two vertical flow constructed wetlands (VFCWs) in series (stages). Many configurations exist, with systems associated with horizontal flow filters or waste stabilization ponds, vertical flow with recirculation, partially saturated systems, etc. A database analyzed 10 years earlier on the classical French system summarized the global performances data. This paper provides a similar analysis of performance data from 415 full-scale two-stage VFCWs from an improved database expanded by monitoring data available from Irstea and the French technical department. Trends presented in the first study are confirmed, exhibiting high chemical oxygen demand (COD), total suspended solids (TSS) and total Kjeldahl nitrogen (TKN) removal rates (87%, 93% and 84%, respectively). Typical concentrations at the second-stage outlet are 74 mgCOD L−1, 17 mgTSS L−1 and 11 mgTKN L−1. Pollutant removal performances are summarized in relation to the loads applied at the first treatment stage. While COD and TSS removal rates remain stable over the range of applied loads, the spreading of TKN removal rates increases as applied loads increase.

scholarly journals Preparation of composite coagulant of PFM-PDMDAAC and its coagulation performance in treatment of landfill leachate

2015 ◽  
Vol 5 (2) ◽  
pp. 177-188 ◽  
Author(s):  
Simin Li ◽  
Yongkang Lv ◽  
Zhanmeng Liu
Keyword(s):  
Landfill Leachate ◽  
Raw Materials ◽  
Oxygen Demand ◽  
X Ray Diffraction ◽  
Mechanical Mixing ◽  
Coagulation Performance ◽  
Coagulation Mechanism ◽  
As Adsorption ◽  
Co Precipitation ◽  
Composite Coagulant

A novel inorganic–organic composite coagulant, poly-ferric-magnesium (PFM) polydimethyldiallylammonium chloride (PDMDAAC), was prepared using FeSO4, MgSO4 and PDMDAAC as raw materials and was introduced to treat landfill leachate. The coagulation performance of the new reagent was evaluated and compared with those of other coagulants. The new reagent was characterized in terms of the analysis of ferron-timed spectroscopy, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The coagulation mechanism was investigated by measuring the ζ-potential reduction and chemical oxygen demand removal at different dosages. Coagulation experiments revealed that the new reagent exhibited better coagulation performance compared with the simple PFM and the PFM + PDMDAAC. Ferron-timed spectroscopy showed that the new reagent exhibited increased effective polymer species concentration. XRD and FTIR spectroscopy showed that the new reagent was not a simple mechanical mixing of PFM and PDMDAAC, but a composite system with inorganic–organic complex interpenetration networks. The predominant coagulation mechanism of the new reagent was charge neutralization at low dosages, as well as adsorption bridging and co-precipitation netting at high dosages, when treating landfill leachate.

Study on Extracting Potassium from Potassium Feldspar with Molten Salt Leaching Method

2012 ◽  
Vol 524-527 ◽  
pp. 1078-1081
Author(s):  
Jian Guo Song ◽  
Xin Zhi Wang ◽  
Shao Dan Xiao ◽  
Wei Liu
Keyword(s):  
Reaction Time ◽  
Molten Salt ◽  
Potassium Feldspar ◽  
Process Conditions ◽  
Temperature Reaction ◽  
Optimal Process ◽  
Potash Feldspar ◽  
Salt Leaching ◽  
Effects Of Temperature

This article aims to study the technology of extracting potassium from potassium feldspar with molten salt leaching method and to analyze the effects of temperature, reaction time and other factors on extracting potassium, concluding the optimal process conditions of extracting potassium with molten leaching method from potash feldspar.

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