Calcium Carbonate Precipitation in Anaerobic Waste Water Treatment

1991 ◽  
Vol 23 (7-9) ◽  
pp. 1239-1248 ◽  
Author(s):  
K. Svardal
Keyword(s):  
Equilibrium Constants ◽  
Waste Water Treatment ◽  
Fixed Bed ◽  
Pilot Scale ◽  
Anaerobic Treatment ◽  
Carbonate Precipitation ◽  
Waste Waters ◽  
Calcium Carbonate Precipitation ◽  
Severe Problem ◽  
Fixed Bed Reactors

Precipitation of calcium in anaerobic treatment can be a severe problem, especially for fixed bed reactors. In order to assess calcium precipitation quantitatively, an equilibrium model has been developed. It is based on concentrations in the influent (COD, TOC, TIC, alkalinity, Ca2+,TKN) conditions in the reactor (pH, temperature) and equilibrium constants. The model has been verified for different waste waters in pilot scale and full scale investigations.

Operational Behaviour of an Industrial Fixed Bed Reactor for Biomethanation of Alcohol Slops from Different Crops

1990 ◽  
Vol 22 (1-2) ◽  
pp. 385-394 ◽  
Author(s):  
P. Weiland ◽  
H. Thomsen
Keyword(s):  
Fixed Bed ◽  
High Strength ◽  
Pilot Scale ◽  
Anaerobic Treatment ◽  
Fixed Bed Reactor ◽  
Two Phase ◽  
Fixed Bed Reactors ◽  
Industrial Unit ◽  
One Year ◽  
Better Than

Distillery slops from a multicrop ethanol plant are difficult to treat anaerobically, because the composition and load changes throughout the year due to processing of different sugar-and starch-containing crops. For achieving high COD removal efficiencies and good process stabilities at medium strength loading rates, a two-phase anaerobic treatment process with a fixed-bed reactor for biomethanation was developed and tested in pilot-scale. On the basis of these experiments a full-scale unit with 1,800 m3 reactor volume was erected, which has been in operation for more than one year. The fixed-bed reactor is operated with COD loads up to 10 kg COD/m3d at hydraulic retention times of about 5 days. A variety of highly concentrated slops can be treated successfully with COD removals from 85 % to over 90 %. The fixed-bed reactor withstood sudden changes in wastewater strength and composition and is able to handle hydraulic overloads. Operational data from the industrial unit show that the performance and reliability of the fixed-bed reactor is much better than a conventional contact system, which was operated in a parallel run in the same scale. The results show, that the application of fixed-bed reactors can be recommended for a wide variety of high-strength wastewaters with low suspended solids contents.

Application of Biofilm Kinetics to Anaerobic Fixed Bed Reactors

1991 ◽  
Vol 23 (7-9) ◽  
pp. 1319-1326 ◽  
Author(s):  
I. E. Gönenç ◽  
D. Orhon ◽  
B. Beler Baykal
Keyword(s):  
Removal Rate ◽  
Fixed Bed ◽  
Experimental Studies ◽  
Pilot Scale ◽  
Cod Removal ◽  
Experimental Results ◽  
Fixed Bed Reactor ◽  
Removal Mechanism ◽  
Term Operation ◽  
Fixed Bed Reactors

Two basic phenomena, reactor hydraulics and mass transport through biofilm coupled with kinetic expressions for substrate transformations were accounted for in order to describe the soluble COD removal mechanism in anaerobic fixed bed reactors. To provide necessary verification, experimental results from the long term operation of the pilot scale anaerobic reactor treating molasses wastewater were used. Theoretical evaluations verified by these experimental studies showed that a bulk zero-order removal rate expression modified by diffusional resistance leading to bulk half-order and first-order rates together with the particular hydraulic conditions could adequately define the overall soluble COD removal mechanism in an anaerobic fixed bed reactor. The experimental results were also used to determine the kinetic constants for practical application. In view of the complexity of the phenomena involved it is found remarkable that a simple simulation model based on biofilm kinetics is a powerful tool for design and operation of anaerobic fixed bed reactors.

Improvement of anaerobic treatment of tannery beamhouse wastewater by an integrated sulphide elimination process

1999 ◽  
Vol 40 (1) ◽  
pp. 245-252 ◽  
Author(s):  
H. Schenk ◽  
M. Wiemann ◽  
W. Hegemann
Keyword(s):  
Hydrogen Sulphide ◽  
Fixed Bed ◽  
Anaerobic Treatment ◽  
Methanogenic Bacteria ◽  
Cod Removal ◽  
Batch Tests ◽  
Treatment Processes ◽  
Fixed Bed Reactors ◽  
Sulphide Toxicity ◽  
High Concentrations

Sulphide, and especially the undissociated form, hydrogen sulphide, is inhibitory to anaerobic wastewater treatment processes. Tannery beamhouse wastewater contains high concentrations of organic material which make an anaerobic treatment favourable, but it also contains high concentrations of sulphide which cause difficulties for anaerobic treatment. The success of an anaerobic treatment will depend on reliable elimination of the sulphide. In batch tests stripping was the most effective process for sulphide removal compared to precipitation. The chemical-physical COD removal caused by the stripping was negligible, while precipitation caused a COD-removal of 26%. Also, anaerobic degradation velocity was higher if sulphide was removed by stripping. In fixed bed reactors operated continuously, stripping was shown to be a reliable method for eliminating hydrogen sulphide toxicity. Hydrogen sulphide caused an inhibition of 0.2% per mg 1−1 for methanogenic bacteria. Acidogenic bacteria were not inhibited by hydrogen sulphide. The gas-liquid equilibrium was shown to deviate from theoretical values taken from literature.

An Anaerobic Fixed Bed Reactor with a Porous Ceramic Carrier

1989 ◽  
Vol 21 (4-5) ◽  
pp. 77-86 ◽  
Author(s):  
Mitsuo Kawase ◽  
Tadashi Nomura ◽  
Tsuyoshi Majima
Keyword(s):  
Loading Rate ◽  
Unit Area ◽  
Porous Ceramic ◽  
Fixed Bed ◽  
Anaerobic Treatment ◽  
Fixed Bed Reactor ◽  
Operational Conditions ◽  
Treatment Performance ◽  
Fixed Bed Reactors ◽  
Highly Loaded

To date, a large number of studies on anaerobic fixed bed reactors have been reported, but there have been few studies on the application of this technology to thermophilic anaerobic treatment. One of the reasons for the small number of applications is the difficulty of attaching thermophilic anaerobic organisms to carriers. The study reported in this paper was conducted to examine the thermophilic treatment performance of an anaerobic fixed bed reactor containing a porous ceramic carrier (‘microbe immobilized ceramic', MIC) developed for the immobilization of anaerobic organisms. When boiled soybean wastewater (55,000 mg/l COD) was treated anaerobically at a high temperature (54°C) in a reactor where 31% of the volume was filled with the MIC carrier, it was found that highly loaded operation with up to 65 kg COD/m3/d was possible. The COD load per unit area of carrier surface under these operational conditions reached 0.397 kg COD/m3/d, and the performance of the reactor was excellent. Stable anaerobic treatment was achieved when the COD loading rate fluctuated from 26 to 51 kg COD/m3/d.

Anaerobic treatment of textile dyeing wastewater

2003 ◽  
Vol 47 (10) ◽  
pp. 55-59 ◽  
Author(s):  
S.R. Stern ◽  
L. Szpyrkowicz ◽  
I. Rodighiero
Keyword(s):  
Fixed Bed ◽  
Textile Wastewater ◽  
Pilot Scale ◽  
Anaerobic Treatment ◽  
Treated Wastewater ◽  
Organic Load ◽  
Microbial Kinetics ◽  
Long Term Study ◽  
Textile Dyeing ◽  
Activated Sludge Processes

Aerobic treatment commonly applied to textile wastewater results in good or even excellent removal of organic load. This is not, however, accompanied by an equally good removal of colour. Traditional or advanced chemical methods of decolourisation are costly and not always reliable in justifying an interest in microbial decolourisation. Among several processes anaerobic methods seem most promising. In this paper, the results of a study conducted in two pilot-scale plants comprising anaerobic fixed bed biofilters of 15 L and 5 m3 operating as continuous reactors are presented, along with evaluation of the microbial kinetics. As is shown the process proved efficient in a long-term study with no stability problems of the biofilters. The six-month performance of the pilot plant confirmed also that the pre-treated wastewater could be applied in the operation of dyeing. For the majority of the colours applied in the factory no problems were encountered when the dyeing baths were prepared by substituting 30% of fresh water to the effluent treated by a sequence of activated sludge processes: anaerobic-aerobic.

Anaerobic treatment of split flow wastewater and concentrates from the textile processing industry

1999 ◽  
Vol 40 (1) ◽  
pp. 169-176 ◽  
Author(s):  
R. Minke ◽  
U. Rott
Keyword(s):  
Fixed Bed ◽  
Anaerobic Treatment ◽  
Cod Removal ◽  
Organic Load ◽  
Textile Processing ◽  
Processing Industry ◽  
Fixed Bed Reactors ◽  
Anaerobic Biodegradability ◽  
Split Flow ◽  
Exhaust Dyeing

Under anaerobic conditions an almost complete decolorization of many dyes, an efficient COD-removal and a digestion of substances that are refractory under aerobic conditions can be obtained. Therefore anaerobic processes can be used to treat highly loaded split flows and concentrates from the textile processing industry (TPI). Using a large number of biodegradability tests on a bench scale, different types of commercial textile auxiliaries, dyes, real split flow effluents from desizing and dyeing processes and real residual printing pastes were tested in regard to their anaerobic biodegradability. Investigations with anaerobic fixed bed reactors (AFBR) showed that it is possible to treat effluents containing a high organic load from desizing processes and highly coloured effluents from exhaust dyeing processes together resulting in high COD-removal and nearly complete decolorization. With respect to the further aerobic removal of the remaining organic load of the AFBR's effluents it could be seen that the decrease of COD-elimination in AFBR resulting from high portions of effluents from exhaust dyeing processes and short hydraulic retention times is compensated by an increase in aerobic BOD-elimination.

Microbiology and chemical engineering-new possibilities for interdisciplinary cooperation in the development of small anaerobic wastewater treatment plants

2000 ◽  
Vol 41 (1) ◽  
pp. 17-20 ◽  
Author(s):  
M. Kozariszczuk ◽  
W. Wenzel ◽  
M. Kraume ◽  
U. Szewzyk
Keyword(s):  
Waste Water ◽  
Chemical Engineering ◽  
Wastewater Treatment Plants ◽  
Waste Water Treatment ◽  
Fixed Bed ◽  
Interdisciplinary Cooperation ◽  
Reactor Performance ◽  
Fixed Bed Reactors ◽  
Microbiological Methods ◽  
Microbiological Parameters

Anaerobic degradation of waste water in fixed bed reactors is investigated using molasses as an example of complex composed waste water. The results of differently sized rectors are shown to be transferable and can be used for the design of small waste water treatment plants. The assessment of the reactor performance is done not only by material balances but also by applying microbiological parameters. Modern microbiological methods enable the incorporation of biological parameters into reactor design and process control. The results of these measurements lead to a better understanding of the correlation between changing process parameters and the state of the microbial population. Thus new tools are available to maintain stable and save anaerobic processes.

Anaerobic Treatment of Sulphur-Containing Effluents

1988 ◽  
Vol 20 (1) ◽  
pp. 133-141 ◽  
Author(s):  
M. Pichon ◽  
J. Rouger ◽  
E. Junet
Keyword(s):  
Energy Savings ◽  
Loading Rate ◽  
Fixed Bed ◽  
Anaerobic Treatment ◽  
Methanogenic Bacteria ◽  
Effluent Treatment ◽  
Thermomechanical Pulp ◽  
Pollution Load ◽  
Sulphur Compounds ◽  
Fixed Bed Reactors

A new method of defibring wood chips and producing chemi-thermomechanical pulp with significant capital and energy savings has been developed. The pollution load of bleached CTMP effluent varied between 40-60 kg/t for BOD5 and 120-210 kg/t for COD. The process includes a sulphite stage and the effluent contains sulphur compounds which are toxic to methanogenic bacteria. Studies have been conducted on anaerobic fixed bed reactors with upflow or downflow feed modes. It is necessary to progressively acclimate bacteria to increasing concentrations of sulphur compounds. Permanent functioning of reactors is possible with COD/S ratios near 10-12 where propionate concentrations are increasing. Upflow reactors are more efficient than downflow reactors, with a maximum loading rate of 3.5 kg COD/m3.day corresponding to 800 mg/l as S. With hybrid sludge bed/fixed bed reactors it is possible to enhance anaerobic treatment efficiency. A COD loading rate of 4.7 kg/m3.day can be maintained with a residence time of 2 days and a pollution load removal efficiency of 45% for COD (55% with complementary oxidation) and 70% for BOD5. The economics of effluent treatment give an investment cost of about 20 US$/ADt for the activated sludge process and 12.5 US$/ADt for anaerobic fixed bed treatment.

Sign in / Sign up

Export Citation Format

Share Document