Fate and toxic effects of cyanide on aerobic treatment systems

2000 ◽  
Vol 42 (3-4) ◽  
pp. 125-129 ◽  
Author(s):  
M.R. Haghighi-Podeh ◽  
G. Siyahati-Ardakani
Keyword(s):  
Chemical Treatment ◽  
Continuous Flow ◽  
Biological Treatment ◽  
Toxic Effects ◽  
Aerobic Treatment ◽  
Chemical Methods ◽  
New Methods ◽  
Effective Technology ◽  
Flow Experiments ◽  
By Products

Many industries discharge significant quantities of cyanide into the environment. Removal of cyanide is a vital task of increasing importance. Currently, the chemical methods of treating cyanide wastewater are used worldwide. The high cost, disposal problems and toxic by-products formation of chemical methods for treating cyanide wastewater has opened the door for more investigation of new methods. This paper evaluates the fate and toxic effects of cyanide on aerobic treatment systems. Both batch and continuous flow experiments were performed. The results indicate that the aerobic biological treatment of cyanide wastewater is an effective technology, which offers many advantages over chemical treatment methods. The microbiological experimental results show that among the microorganisms present in the culture, oscillatoria, philodina, carchesium, pseudomonas and bacillus bacteria were resistant to cyanide and capable of biodegrading it. The results of this study indicate that biodegradation and sorption of cyanide are the most important and least important removal mechanisms, respectively.

Biodegradation of microcystin [Dha7]MC-LR by a novel microcystin-degrading bacterium in an internal airlift loop bioreactor

2015 ◽  
Vol 73 (2) ◽  
pp. 267-274 ◽  
Author(s):  
Yupin Phujomjai ◽  
Anchana Somdee ◽  
Theerasak Somdee
Keyword(s):  
Health Problem ◽  
Continuous Flow ◽  
Microtiter Plate ◽  
Degrading Bacterium ◽  
Flow Experiment ◽  
Airlift Loop ◽  
Bodies Of Water ◽  
Cluster Gene ◽  
Flow Experiments ◽  
By Products

Cyanobacterial hepatotoxin microcystins are a health problem found in bodies of water in Thailand. Bacteria capable of biodegrading microcystin [Dha7]MC-LR were isolated from the Bueng Nong Khot reservoir in Khon Kaen, Thailand. The bacterium Novosphingobium isolate KKU25s was shown to degrade [Dha7]MC-LR at a concentration of 25 μg l−1 at 30 °C within 24 h. Two intermediate by-products (linearized peptide and tetrapeptide) and a cluster gene (mlrA, mlrB, mlrC and mlrD) that encodes four putative enzymes involved in [Dha7]MC-LR degradation were detected in KKU25s. KKU25s was also shown to form strong biofilms in microtiter plate assays. These assays were carried out in preparation for use of the bacterium in a bioreactor for [Dha7]MC-LR degradation. In an internal airlift loop bioreactor, the biodegradation of [Dha7]MC-LR by the bacterium was established in batch and continuous flow experiments. In the batch experiment, KKU25s degraded [Dha7]MC-LR at a concentration of 25 μg l−1 at 30 °C within 24 h, whereas in the continuous flow experiment, KKU25s degraded the toxin at the same concentration within 36 h. This study demonstrated that this bacterium could potentially be used to remove microcystins from water.

β-Cyclodextrin Polymers on Microcrystalline Cellulose as a Granular Media for Organic Micropollutant Removal from Water

2018 ◽  
Author(s):  
Diego Alzate-Sanchez ◽  
Yuhan Ling ◽  
Chenjun Li ◽  
Benjamin Frank ◽  
Reiner Bleher ◽  
...  
Keyword(s):  
Microcrystalline Cellulose ◽  
Continuous Flow ◽  
Granular Media ◽  
Anaerobic Biodegradation ◽  
Thin Coating ◽  
Micropollutant Removal ◽  
Cyclodextrin Polymers ◽  
Flow Experiments ◽  
Aerobic And Anaerobic ◽  
Cellulose Composite

This manuscript describes cyclodextrin polymers formed as a thin coating on microcrystalline cellulose. The resulting polymer/cellulose composite shows promising performance for removing organic pollutants from water and can be packed into columns for continuous-flow experiments. The polymer/cellulose composite also shows excellent resistance to aerobic and anaerobic biodegradation.

Characterization and treatability studies of cigarette industry wastewaters: a case study

1997 ◽  
Vol 36 (2-3) ◽  
pp. 69-74
Author(s):  
G. Bozarslan ◽  
S. K. Çelebi ◽  
F. Sengül
Keyword(s):  
Chemical Treatment ◽  
Biological Treatment ◽  
Continuous System ◽  
Cod Removal ◽  
Optimum Dose ◽  
Fenton Reagent ◽  
Cigarette Industry ◽  
Settling Behaviour ◽  
Characterization Studies

In this study, the wastewater of one of the cigarette factories in Izmir was characterized and treatability studies were done. The characterization studies of the wastewater showed that the COD, and the pH changes drastically. The chemical treatability studies of the influent wastewater were done by using Ca(OH)2, FeCl3 and Fenton Reagent. The optimum dose of FeCI3 was determined by jar tests. When using Ca(OH)2, the best flocculation, settling behaviour, and the highest COD removal occurred around pH 11. The optimum doses of Fenton Reagent (FeSO4 and H2O2) were determined. The supernatants of the previously chemically treated wastewaters were used for biological treatment. According to total COD removal efficiencies and the amount of sludge production during chemical treatment, FeCl3 was found to be the most economical and effective coagulant. Chemical treatment units were designed for a batch and a continuous system. The batch system has more advantages than a continuous system in this case.

Automated generation of photochemical reaction data by transient flow experiments coupled with online HPLC analysis

2020 ◽  
Vol 5 (5) ◽  
pp. 912-920
Author(s):  
Christian P. Haas ◽  
Simon Biesenroth ◽  
Stephan Buckenmaier ◽  
Tom van de Goor ◽  
Ulrich Tallarek
Keyword(s):  
Continuous Flow ◽  
Photochemical Reaction ◽  
Hplc Analysis ◽  
Transient Flow ◽  
Data Sets ◽  
Automated Generation ◽  
Reaction Data ◽  
Flow Experiments

Competing homo- and crossdimerization reactions between coumarin and 1-methyl-2-quinolinone are investigated by transient continuous-flow experiments combined with online HPLC, enabling the generation and acquisition of large reaction data sets.

scholarly journals Evaluation of a Non-Chemical Compared to a Non-Chemical Plus Silica Gel Approach to Bed Bug Management

Insects ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 443
Author(s):  
Salehe Abbar ◽  
Changlu Wang ◽  
Richard Cooper
Keyword(s):  
Silica Gel ◽  
Chemical Treatment ◽  
Bed Bugs ◽  
Chemical Methods ◽  
Bed Bug ◽  
Treatment Groups ◽  
Dust Treatment ◽  
Residual Control ◽  
Insecticide Sprays ◽  
Bug Management

Bed bug resistance to commonly used pesticide sprays has led to exploring new pesticides and other strategies for bed bug management. Non-chemical methods are effective in bed bug management; however, they do not provide residual protection. Compared to insecticide sprays, dust formulations are considered to provide longer residual control. We evaluated two bed bug management programs in apartment buildings. A building-wide inspection was initially conducted to identify bed bug infested apartments. Selected apartments were divided into two treatment groups: non-chemical plus silica gel dust treatment (10 apartments) and non-chemical treatment (11 apartments). After initial treatment, apartments were re-visited monthly for up to 6 months. During each visit, the total bed bug count per apartment was obtained by examining interceptor traps placed in the apartments and conducting a visual inspection. Mean bed bug count was reduced by 99% and 89% in non-chemical plus silica gel dust and non-chemical treatment, respectively. Non-chemical plus silica gel dust treatment caused significantly higher bed bug count reduction than the non-chemical treatment at 6 months. Bed bugs were eradicated from 40% and 36% of apartments treated with non-chemical plus silica gel dust treatment and non-chemical treatment, respectively.

Sustainable Utilization of Sewage Sludge: Review of Technologies

2018 ◽  
Vol 762 ◽  
pp. 121-125 ◽  
Author(s):  
Agnese Stunda-Zujeva ◽  
Imants Kreicbergs ◽  
Olita Medne
Keyword(s):  
Industrial Wastewater ◽  
Biological Treatment ◽  
Mineral Resources ◽  
Wastewater Sludge ◽  
Secondary Source ◽  
Sustainable Utilization ◽  
Toxic Substances ◽  
Sludge Treatment ◽  
Industrial Sludge ◽  
New Methods

Biological treatment of municipal and industrial wastewater becomes more common in EU countries. As a result, the amount of wastewater sludge increases. The political and economic situation in world is requiring new methods for recovery of non-renewable mineral resources. Sludge is great secondary source of many elements. The aim of this research is to summarize available techniques for sustainable utilization of industrial sludge and recovery of critical raw minerals (CRMs). The most common sustainable method is using treated sludge as fertilizer in agriculture due to high content of P, N, C and microelements. However, this method has many restrictions, e.g. it can contain toxic substances or lack of appropriate land. Thermal sludge treatment methods like pyrolysis have developed crucially in last decade and pyrolysis units for sludge treatment are commercially available now. Pyrolysis becomes the most sustainable method due to recovery of CRMs and better energy recovery comparing to incineration.

Implementation of EU discharge guidelines at IVAR's Regional Wastewater Treatment Plant of North Jaeren, Stavanger, Norway

2001 ◽  
Vol 44 (1) ◽  
pp. 33-39 ◽  
Author(s):  
O. Tornes
Keyword(s):  
Wastewater Treatment ◽  
Feasibility Study ◽  
Chemical Treatment ◽  
Biological Treatment ◽  
Treatment Plant ◽  
Primary Treatment ◽  
Full Scale ◽  
Precipitation Process ◽  
European Economic Area ◽  
The Eu

Norway is a leading country on wastewater treatment comprising chemical precipitation processes. This is because Norwegian effluent standards to the North Sea have traditionally focused on phosphorus removal. In most cases, chemical treatment therefore has been considered to give lower investment and operating costs than biological treatment. Norwegian wastewater policy and management is based on the EU guidelines resulting from the EEA (European Economic Area) Agreement. According to the 1991 Urban Wastewater Treatment Directive, this will in most cases require secondary treatment. However, primary treatment can be accepted for plants larger than 10,000 PT with effluents to less sensitive coastal areas, if no negative environmental impacts can be proved. The main objective of the Regional Water, Sewerage and Waste Company (IVAR) is to comply with the prevailing effluent limits at lowest possible cost. During the past four years, IVAR has therefore undertaken comprehensive optimising of the precipitation process including full-scale experiments with different coagulant dosing control systems and different types of coagulants. IVAR also accomplished a feasibility study of introducing biological treatment as an alternative to chemical treatment. Under the prevailing frame conditions of discharge requirements and sludge deposit costs, it is not economically feasible to change to organic coagulants or biological treatment. This conclusion might have to be altered later resulting from the implementation of new EU regulations and increasing sludge deposit costs. This paper presents results from full-scale experiments, extracts from the feasibility study and a comparison of costs. Furthermore, the practical consequences of implementing the EU-guidelines are discussed.

Anaerobic and Aerobic Treatment for AOX Removal

1994 ◽  
Vol 29 (5-6) ◽  
pp. 149-162 ◽  
Author(s):  
John F. Ferguson
Keyword(s):  
Biological Treatment ◽  
Anaerobic Treatment ◽  
Reductive Dehalogenation ◽  
Aerobic Treatment ◽  
Abiotic Degradation ◽  
In Series ◽  
Kraft Mill ◽  
Significant Chemical ◽  
Aox Removal ◽  
Aerobic And Anaerobic

A two-year study has focused on AOX removal from bleaching wastewaters in anaerobic and aerobic biological treatment, using bench scale bioreactors operated in parallel and in series. Significantly higher removals have been found in anaerobic than in aerobic treatment. Earlier work with dilute kraft bleaching wastes has been extended in additional laboratory tests and at a nearby kraft mill. 50-75% fractions of bleaching wastes were treated. Toxicity in the anaerobic process was encountered at 85% bleach waste fractions. Total AOX removal experienced in aerobic treatment is 30-35%, in anaerobic treatment 40-45%, and in an anaerobic/aerobic sequence 50-55%. Percentage removals were not sensitive to the fraction of bleaching wastewater. Several process modifications were attempted to try to obtain higher removals with only marginal success. Studies at a kraft mill confirmed the AOX removals that had been found in lab studies. AOX removal occurs by several mechanisms. There is a very significant chemical or abiotic degradation that occurs after neutralization, perhaps enhanced by reductants or other inorganic salts. Biological processes are much more significant in anaerobic than in aerobic treatment. Anaerobic reductive dehalogenation affects specific chlorinated compounds and catalyzed AOX degradation is facilitated by reduced coenzymes that are produced by bacteria. Removal by sorption or insolubilization is relatively minor in aerobic and anaerobic processes.

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