Attached versus Suspended Growth Anaerobic Reactors: Response to Toxic Substances

1983 ◽  
Vol 15 (8-9) ◽  
pp. 261-289 ◽  
Author(s):  
G F Parkin ◽  
R E Speece
Keyword(s):  
Chronic Toxicity ◽  
Waste Treatment ◽  
Plug Flow ◽  
Toxic Substances ◽  
Attached Growth ◽  
Industrial Wastewaters ◽  
Anaerobic Reactors ◽  
Suspended Growth ◽  
Solids Retention ◽  
Growth System

Anaerobic methane fermentation has significant potential for treatment of industrial wastewaters. Application of the process has been limited, due in part to the belief that the process cannot tolerate chronic and transient toxicity inherent in many industrial wastewaters. Experiments with cyanide, chloroform, formaldehyde, ammonium, nickel and sulfide have shown that the methanogens have the ability to recover from and acclimate to relatively high concentrations of toxicants. The key is proper attention to solids retention time. Of the two general reactor types used in biological waste treatment, attached growth systems offer two major potential advantages over suspended growth systems for treating wastewaters containing toxicants: (1) higher inherent solids retention times at relatively low hydraulic retention times and (2) the potential for a quasi plug-flow hydraulic regime that allows rapid elution of toxicants. For transient toxicity, the ability of a plug-flow, attached growth system to rapidly elute toxicants resulted in dramatically reduced down times when compared to a complete-mix, suspended growth system. For chronic toxicity, the solids retention capability of attached growth systems allows for acclimation to occur prior to washout of active biomass. Effluent recycle to plug-flow, attached growth systems should allow for more gradual exposure to chronic toxicity, thus maximizing acclimation potential.

Vacuum Operation for Overloaded Anaerobic Treatment Systems

1989 ◽  
Vol 21 (4-5) ◽  
pp. 87-95
Author(s):  
J. De Santis ◽  
A. A. Friedman
Keyword(s):  
Volatile Fatty Acids ◽  
Loading Rate ◽  
Anaerobic Treatment ◽  
Optimum Operating ◽  
Operating Pressure ◽  
Simple Modification ◽  
Anaerobic Reactors ◽  
Fixed Film ◽  
Solids Retention ◽  
High Concentrations

Overloaded anaerobic treatment systems are characterized by high concentrations of volatile fatty acids and molecular hydrogen and poor conversion of primary substrates to methane. Previous experiments with fixed–film reactors indicated that operation with reduced headspace pressures enhanced anaerobic treatment. For these studies, four suspended culture, anaerobic reactors were operated with headspace pressures maintained between 0.5 and 1.0 atm and a solids retention time of 15 days. For lightly loaded systems (0.4 g SCOD/g VSS-day) vacuum operation provided minor treatment improvements. For shock organic loads, vacuum operation proved to be more stable and to support quicker recovery from upset conditions. Based on these studies and a companion set of bioassay tests, it was concluded that: (a) a loading rate of about 1.0 g SCOD/g VSS-day represents a practical loading limit for successful anaerobic treatment, (b) a headspace pressure of approximately 0.75 atm appears to be an optimum operating pressure for anaerobic systems and (c) simple modification to existing systems may provide relief for organically overloaded systems.

Advances in high rate anaerobic treatment: staging of reactor systems

2001 ◽  
Vol 44 (8) ◽  
pp. 15-25 ◽  
Author(s):  
J.B. van Lier ◽  
F.P. van der Zee ◽  
N.C.G. Tan ◽  
S. Rebac ◽  
R. Kleerebezem
Keyword(s):  
Cost Effective ◽  
Anaerobic Treatment ◽  
High Rate ◽  
Extreme Conditions ◽  
Waste Streams ◽  
Textile Processing ◽  
Anaerobic Wastewater Treatment ◽  
Anaerobic Reactors ◽  
Wide Acceptance ◽  
Solids Retention

Anaerobic wastewater treatment (AnWT) is considered as the most cost-effective solution for organically polluted industrial waste streams. Particularly the development of high-rate systems, in which hydraulic retention times are uncoupled from solids retention times, has led to a world-wide acceptance of AnWT. In the last decade up to the present, the application potentials of AnWT are further explored. Research shows the feasibility of anaerobic reactors under extreme conditions, such as low and high temperatures. Also toxic and/or recalcitrant wastewaters, that were previously believed not to be suitable for anaerobic processes, are now effectively treated. The recent advances are made possible by adapting the conventional anaerobic high-rate concept to the more extreme conditions. Staged anaerobic reactor concepts show advantages under non-optimal temperature conditions as well as during the treatment of chemical wastewater. In other situations, a staged anaerobic - aerobic approach is required for biodegradation of specific pollutants, e.g. the removal of dyes from textile processing wastewaters. The current paper illustrates the benefits of reactor staging and the yet un-exploited potentials of high-rate AnWT.

Implementation of attached growth system in Malaysia: An overview

2016 ◽  
pp. 235-239
Author(s):  
Gasim Hayder ◽  
Nur Fu’ad ◽  
Puniyarasen Perumulselum
Keyword(s):  
Attached Growth ◽  
Growth System

scholarly journals Toxicity, bioaccumulation and biotransformation of glucose capped silver nanoparticles in green microalgae Chlorella vulgaris

2020 ◽  
Author(s):  
Stefania Mariano ◽  
Elisa Panzarini ◽  
Maria Dias Inverno ◽  
Nikolaos Voulvoulis ◽  
Luciana Dini
Keyword(s):  
Silver Nanoparticles ◽  
Chlorella Vulgaris ◽  
Waste Treatment ◽  
Sea Urchins ◽  
Aquatic Organism ◽  
Consumer Products ◽  
Toxic Substances ◽  
Dependent Manner ◽  
Green Microalgae ◽  
Dose Dependent

Abstract BackgroundSilver nanoparticles (AgNPs) are one of the most widely used nanomaterials in consumer products. When discharged into the aquatic environment AgNPs can cause toxicity to aquatic biota, through mechanisms that are still under debate, thus rendering the NPs effects evaluation a necessary step. Different aquatic organism models, i.e. microalgae, mussels, Daphnia magna, sea urchins and Danio rerio, etc. have been largely exploited for NPs toxicity assessment. On the other hand, alternative biological microorganisms abundantly present in nature, i.e. microalgae, are nowadays exploited as a potential sink for removal of toxic substances from the environment. Indeed, the green microalgae Chlorella vulgaris is one of the most used microorganisms for waste treatment.ResultsWith the aim to verify the possible involvement of C. vulgaris not only as a model microorganism of NPs toxicity but also for the protection toward NPs pollution, we used these microalgae to measure the AgNPs biotoxicity and bioaccumulation. In particular, to exclude any toxicity derived by Ag+ ions release, green chemistry synthesised and Glucose coated AgNPs (AgNPs-G) were used. C. vulgaris actively internalised AgNPs-G whose amount increases in a time and dose-dependent manner. The internalised NPs, found inside large vacuoles, were not released back into the medium, even after 1 week, and did not undergo biotransformation since AgNPs-G maintained their crystalline nature. Biotoxicity of AgNPs-G causes an exposure time and AgNPs-G dose-dependent growth reduction and a decrease in chlorophyll-a amount.ConclusionsThese results confirm C. vulgaris as a biomonitoring organism and also suggest it as a bioaccumulating microalgae for possible use in the environment protection.

scholarly journals Resuscitation of starved suspended- and attached-growth anaerobic ammonium oxidizing bacteria with and without acetate

2016 ◽  
Vol 75 (1) ◽  
pp. 115-127 ◽  
Author(s):  
Supaporn Phanwilai ◽  
Chalermraj Wantawin ◽  
Akihiko Terada ◽  
Pongsak (Lek) Noophan ◽  
Junko Munakata-Marr
Keyword(s):  
Nutrient Removal ◽  
Short Term ◽  
Attached Growth ◽  
Copy Numbers ◽  
Anammox Activity ◽  
Suspended Growth

Anammox application for nutrient removal from wastewater is increasing, though questions remain about anammox resilience to fluctuating conditions. Resuscitation of anammox suspended- and attached-growth cultures after 3 months of starvation was studied with and without acetate dosing. Without acetate, the attached-growth culture recovered more quickly than the suspended-growth culture. Suspended-growth cultures recovered more quickly (within 60 days) with weekly and daily acetate dosing than without, but anammox activity and copy numbers decreased with continued acetate addition. All attached-growth cultures recovered within 60 days, but after that activity with acetate dosing was consistently at least 20% lower than that without acetate addition. Ca. Jettenia caeni, Ca. Anammoxoglobus sp., Ca. Brocadia fulgida, Ca. Brocadia anammoxidans, Ca. Brocadia fulgida and Ca. Jettenia asiatica were identified. Acetate addition can significantly accelerate short-term resuscitation of enriched anammox suspended-growth cultures after starvation but may reduce anammox activity over the longer term in suspended- and attached-growth cultures.

The impact of biofilm thickness-restraint and carrier type on attached growth system performance, solids characteristics and settleability

2020 ◽  
Vol 6 (10) ◽  
pp. 2843-2855
Author(s):  
Raheleh Arabgol ◽  
Peter A. Vanrolleghem ◽  
Maria Piculell ◽  
Robert Delatolla
Keyword(s):  
Physical Properties ◽  
System Performance ◽  
Attached Growth ◽  
Biofilm Thickness ◽  
Growth System ◽  
The Impact

MBBR carrier type and physical properties have a significant effect on the solids production, detachment and subsequently the solids distribution size and settleability.

Review on biological wastewater treatment and resources recovery: attached and suspended growth systems

2019 ◽  
Vol 80 (11) ◽  
pp. 2013-2026 ◽  
Author(s):  
Lakshmi Machineni
Keyword(s):  
Wastewater Treatment ◽  
Biological Treatment ◽  
Film Growth ◽  
Value Added ◽  
Microbial Consortia ◽  
Biological Wastewater Treatment ◽  
Suspended Growth ◽  
Growth System ◽  
Pure Cultures ◽  
Biological Methods

Abstract The treatment of wastewater for reuse is a potential solution to meet ever increasing urban, industrial, agricultural, and environmental demands across the world, where clean water availability is scarce. There are several traditional wastewater treatment processes that offer varying degrees of effectiveness in addition to presenting environmental, economic, and social disadvantages. Development of promising and inexpensive technologies to provide the reusable water in needful amounts using wastewaters as a cheap source of key nutrients and organic matter is required. Wastewater treatment by biological methods is becoming more important in the light of recovering value-added plant nutrients, heavy metals, biosolids, and bioenergy resources. Different types of solid contaminants in effluents can be removed simultaneously by pure cultures or mixed microbial consortia. Based on the structural organization of microbial biomass, biological treatment systems are classified into two types: dispersed growth system and attached growth system. Biological treatment methods associated with fixed-film growth have been recognized as highly effective and more energy efficient than suspended growth systems. This review discusses the recent breakthroughs in advanced biological wastewater treatment using both the systems, and also focuses on key energetic resources recovery driven by biological technologies.

Simultaneous removal of ammonium-nitrogen and sulphate from wastewaters with an anaerobic attached-growth bioreactor

2006 ◽  
Vol 54 (8) ◽  
pp. 27-35 ◽  
Author(s):  
Q.-l. Zhao ◽  
W. Li ◽  
S.-j. You
Keyword(s):  
Molecular Nitrogen ◽  
Ammonium Nitrogen ◽  
Sodium Sulphate ◽  
Simultaneous Removal ◽  
Attached Growth ◽  
Bacteria Growth ◽  
Industrial Wastewaters ◽  
Loading Rates ◽  
Reducing Bacteria ◽  
Natural Water Bodies

Some industrial wastewaters may contain ammonium-nitrogen and/or sulphate, which need to be removed before their discharge into natural water bodies to eliminate their severe pollution. In this paper, simultaneous removal of ammonium-nitrogen and sulphate with an anaerobic attached-growth bioreactor of 3.8 L incubated with sulphate reducing bacteria (SRB) was investigated. Artificial wastewater containing sodium sulphate as electron acceptor, ammonium chlorine as electron donor and glucose as carbon source for bacteria growth was used as the feed for the bioreactor. The loading rates of ammonium-nitrogen, sulphate and COD were 2.08 gN/m3·d, 2.38 gS/m3·d, 104.17 gCOD/m3·d, respectively, with a N/S ratio of 1:1.14. The results demonstrated that removal rates of ammonium-nitrogen, sulphate and COD could reach 43.35%, 58.74% and 91.34%, respectively. Meanwhile, sulphur production was observed in effluent as well as molecular nitrogen in biogas, whose amounts increased with time substantially, suggesting the occurrence of simultaneous removal of ammonium-nitrogen and sulphate. This novel reaction provided the possibility to eliminate ammonium-nitrogen and sulphate simultaneously with accomplishment of COD removal from wastewater, making wastewater treatment more economical and sustainable.

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