Treatment of easily biodegradable wastewater avoiding bulking sludge

2002 ◽  
Vol 46 (1-2) ◽  
pp. 503-506 ◽  
Author(s):  
N. Matsché ◽  
S. Winkler ◽  
L. Prendl ◽  
K. Dornhofer ◽  
G. Wandl
Keyword(s):  
Treatment Plant ◽  
Gas Production ◽  
Aeration Tank ◽  
Biodegradable Material ◽  
Excess Sludge ◽  
Food Industries ◽  
Biological Sludge ◽  
New Process ◽  
One Year ◽  
Treatment Alternatives

The presence of easily degradable compounds from food industries frequently leads to bulking problems. The paper describes a new process that has been developed for a dairy in Austria. Because of the increase in production the treatment plant receiving the wastewater up to now was not able to handle the increased loads. Therefore detailed studies for treatment alternatives have been undertaken which led to a completely new concept. The excess sludge of the urban treatment plant is contacted with the concentrated dairy waste in a separate contact tank. In this tank the easily degradable substrate from the industrial waste is mainly adsorbed to the biological sludge and after a mechanical dewatering transferred to the anaerobic digester where it yields an increased gas production. The filtrate of the dewatering process is completely free from biodegradable material and can without danger of bulking be fed to the aeration tank. The process has been in operation for more than one year and has fulfilled all expectations.

Improvement of existing nightsoil treatment plant for nitrogen removal

2004 ◽  
Vol 49 (5-6) ◽  
pp. 273-279
Author(s):  
B.S. Lim ◽  
J.U. Kim ◽  
H.D. Park
Keyword(s):  
Nitrogen Removal ◽  
Removal Rate ◽  
Treatment Plant ◽  
Second Step ◽  
Aeration Tank ◽  
Oxidation Ditch ◽  
Treatment Efficiency ◽  
Operation And Maintenance ◽  
One Year ◽  
Efficiency Rate

This study was performed to increase the treatment efficiency and to reduce operation and maintenance costs of the existing nightsoil treatment plant. The existing nightsoil plant was not established by the nitrogen removal process, and was operated ineffectively with deterioration of treatment efficiency rate, and according to the demand of many operators, the expenses of operation and maintenance have become excessive. Modified plant has been changed through two steps. The first step, liquid decayed tank using closed oxidation ditch is operated to increase retention time only for nitrification. The second step, modified liquid decayed tank including anoxic tank is operated, it has an excellent nitrogen removal rate. In first step, when HRT was increased from 10 days to 13 days in liquid decayed tank including aeration tank using closed oxidation ditch, TN concentration of effluent appeared below 51 mg/l less than discharge limit, 60 mg/L. In second step, when anoxic tank and oxic tank were installed, HRT has been increased to 13 days and 26 days, respectively. Then average TN concentration of effluent was detected less than 13 mg/L for over one year. The simple process modified the existing two processes resulted in the reduction of costs for operation and maintenance in the personnel, chemical, and filter change sphere.

Complete decomposition of biological waste sludge by thermophilic aerobic bacteria

2000 ◽  
Vol 42 (9) ◽  
pp. 81-88 ◽  
Author(s):  
Y. Sakai ◽  
T. Aoyagi ◽  
N. Shiota ◽  
A. Akashi ◽  
S. Hasegawa
Keyword(s):  
High Efficiency ◽  
Municipal Sewage ◽  
Aerobic Bacteria ◽  
Municipal Sewage Sludge ◽  
Aeration Tank ◽  
Petrochemical Plant ◽  
Bacillus Sp ◽  
Excess Sludge ◽  
Complete Decomposition ◽  
New Process

Conventional activated sludge (AS) process is an economical and effective biooxidation process although a large amount of excess sludge is necessarily generated. We have developed a new zero-discharge AS process, in which no excess sludge is generated. It was formed by combining the conventional AS process with thermophilic aerobic sludge digester in which excess sludge is solubilized by thermophilic enzyme, so we call it hereafter the digester S-TE reactor. The excess sludge withdrawn from the AS step is subjected to the S-TE reactor, followed by its circulation to an aeration tank. Complete decomposition of the excess sludge is carried out when the sludge is solubilized by thermophilic aerobic bacteria (e.g. Bacillus sp.) and mineralized by mesophilic bacteria. The S-TE reactor is operated at 65°C with hydraulic retention time of 1 day. Bench-scale test facilities of both the new process and conventional AS process were comparatively operated under the conditions of BOD-SS loading of 0.3 kg/kg/dand MLSS of 2,000 mg/L using artificial wastewater for over 100 days. The S-TE reactor was initially inoculated with the seedling culture of isolated Bacillus sp. bacteria. No additional inoculation seem to be needed under the steady condition since these bacteria can form spores and survive even under mesophilic conditions. The average rates of VSS solubilization and VM removal in the S-TE reactor were 40% and 15%, respectively. No excess sludge was generated when 3-fold amounts of the excess sludge generated in the conventional AS process were subjected to the S-TE reactor. In the new process, BOD was removed with high efficiency. Slight increase of SS and TOC was observed when compared with those of the AS process. A pilot-scale facility of the process has been operated with a petrochemical plant wastewater for a year. MLSS concentration was continuously kept around 3,000 mg/L without withdrawing the excess sludge. Inorganic salts seemed not to accumulate in the process. Therefore, it was demonstrated that excess sludge generation was completely reduced in the new process. According to our estimates, total operating costs for the new process are reduced to 40-50% of those of the conventional wastewater dewatering process. An application to a municipal sewage sludge treatment is currently performed in its full-scale facility.

Landfarming – A Solution for the Treatment and Final Disposal of Biological Sludge in Cetrel Waste Treatment Plant, Brazil

1987 ◽  
Vol 19 (8) ◽  
pp. 27-32
Author(s):  
P R. C. de Oliveira ◽  
P. R. Filho
Keyword(s):  
Waste Treatment ◽  
Treatment Plant ◽  
Effluent Treatment ◽  
Final Disposal ◽  
Admission Rates ◽  
Biological Sludge ◽  
Pilot Plant Test ◽  
Waste Treatment Plant ◽  
Plant Test ◽  
One Year

The Treatment Plant of CETREL - Central de Tratamento de Efluentes Líquidos S/A (Liquid Effluent Treatment Plant)-processes the organic wastes of fortyfive industries installed in Camaçari Petrochemical Complex which represent today an or ganic load of approximately 45,000 kg/BOD/day and an ammoniacal nitrogen load of 9000 kg/day. Our intention is to describe, in an objective and practical manner, the solution adopted for the final disposal of biological sludge, focusing on the reasons for the choice of landfarming, pilot plant test, unit design, sludge layer admission rates, the equipment used,the results of biodegradability, the importance of the choice of the soil Which is to operate as a reactive layer, the influence of heavy metals, the monitoring of ground water and, finally, the results obtained after one year of operation.

A strategy in wastewater treatment process for significant reduction of excess sludge production

2002 ◽  
Vol 45 (12) ◽  
pp. 127-134 ◽  
Author(s):  
N. Shiota ◽  
A. Akashi ◽  
S. Hasegawa
Keyword(s):  
Wastewater Treatment ◽  
Treatment Process ◽  
Pilot Scale ◽  
Aeration Tank ◽  
Excess Sludge ◽  
Wastewater Treatment Process ◽  
Conventional Activated Sludge ◽  
New Process ◽  
Treatment Step ◽  
Sludge Production

A novel wastewater treatment process (S-TE PROCESS®) with significantly reduced production of excess sludge has been developed. The process consists of two different stages, one for a biological wastewater treatment and the other for a thermophilic aerobic digestion of the resulting sludge. A portion of return sludge from the wastewater treatment step is injected into a thermophilic aerobic sludge digester (TASD), in which the injected sludge is solubilized by the action of thermophilic aerobic bacteria. The solubilized sludge is returned to the aeration tank in the wastewater treatment step for its further degradation. Pilot-scale facilities of the S-TE process and the conventional activated sludge process as a control, both treating the same industrial wastewater, were comparatively operated for totally 270 days. As a result, 93% reduction in overall excess sludge production was achieved in the S-TE operation. The SS solubilization rate in TASD was stable at around 30%. Only a slight increase in the effluent SS and TOC concentrations was observed compared with those of the control facility. Otherwise the removal efficiency of TOC was approximately 95% for both plants. A full-scale plant treating domestic sewage was operated for three years, showing 75% reduction of overall excess sludge production. It was concluded that the new process was feasible.

Thermophilic anaerobic digestion and pasteurisation. Practical experience from Danish wastewater treatment plants

2000 ◽  
Vol 42 (9) ◽  
pp. 65-72 ◽  
Author(s):  
B. Nielsen ◽  
G. Petersen
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Stable Process ◽  
Treatment Plant ◽  
Practical Experience ◽  
Full Scale ◽  
Excess Sludge ◽  
Biological Sludge ◽  
The Moment ◽  
Under Construction

Increasing sludge disposal costs have highly intensified the interest in reducing the sludge quantities from Danish wastewater treatment plants. By upgrading existing mesophilic digesters to the thermophilic temperature range, the retention time can be halved and many digesters designed only for primary sludge will have sufficient capacity to treat also the biological excess sludge. At the moment, eight full-scale thermophilic digesters are in operation in Denmark and five are under construction. This paper describes the full-scale experience gained from digestion of biological excess sludge as well as a mixture of primary and biological sludge. Thermophilic digestion has proven to be a good and stable process for solids reduction and pathogen removal. The digested sludge can be dewatered to a high solids content and thereby the sludge quantity for disposal can be reduced by 30-40% depending on the type of wastewater treatment plant. A drawback of the process is that the polymer costs for sludge dewatering may be increased depending on the sludge type.

An innovative approach to reduce excess sludge production in the activated sludge process

1994 ◽  
Vol 30 (9) ◽  
pp. 11-20 ◽  
Author(s):  
H. Yasui ◽  
M. Shibata
Keyword(s):  
Activated Sludge ◽  
Biomass Concentration ◽  
Experimental Period ◽  
Aeration Tank ◽  
Activated Sludge Process ◽  
Biological Degradation ◽  
Excess Sludge ◽  
Conventional Activated Sludge ◽  
New Process ◽  
Sludge Production

A new process has been developed to reduce excess sludge production, in which both excess sludge digestion and wastewater treatment are conducted simultaneously in the same aeration tank. The ozonation enhances biological degradation of the activated sludge, which is decomposed in a subsequent biological treatment. A considerable amount of biomass is mineralized biologically in proportion to the amount of recirculated biomass from the ozonation stage to the biological stage. It was observed that the amount of excess sludge is reduced to nearly zero when 1.2 kg/m3-aeration tank volume of biomass is recirculated in a day from the biological stage to the ozonation stage at a BOD loading of 1.0 kg/m3/d. A biomass concentration of 4200 mg/L was maintained at 1.0 kg-BOD/m3/d without drawing excess sludge for 6 weeks of experimental period under ozone dose of 0.05 g-O3/g-SS and recirculation rate at 0.3 d−1. Only a limited difference in the effluent quality was observed between the new process and the conventional activated sludge process.

A new side stream process for easily degradable industrial waste waters to avoid sludge bulking

2004 ◽  
Vol 50 (7) ◽  
pp. 229-236
Author(s):  
G. Wandl ◽  
N. Matsché ◽  
H. Bayer
Keyword(s):  
Waste Water ◽  
Industrial Waste ◽  
Treatment Plant ◽  
Aeration Tank ◽  
Waste Waters ◽  
Excess Sludge ◽  
Treatment Line ◽  
Peak Loads ◽  
Side Stream ◽  
Dairy Waste

A new treatment scheme for the treatment of easily biodegradable industrial waste waters has been developed. The side stream treatment of dairy waste water with the excess sludge from the domestic treatment line of the regional treatment plant Bad Vöslau has been operated successfully for a period of three years during which the industrial load stemming from the dairy increased from 800 kg COD/d to 2,500 kg COD/d with peak loads up to 5,000 kg/d. Despite of the increased load to the treatment plant the total aeration tank volume had not been increased. This treatment is performed in an existing aeration tank of the WWTP (V = 1,800 m3) which is now used as contact tank for the combined aeration of dairy waste water and excess sludge from the domestic treatment line (volume aeration tank = 15,000 m3). In this tank the easily degradable substrate from the industrial waste is mainly adsorbed to the biological sludge and after a mechanical dewatering transferred to the anaerobic digester where it yields in an increased gas production. The filtrate of the dewatering process is completely free from biodegradable material and can without danger of bulking be fed to the aeration tank of the domestic treatment line. The new process has proven to be extremely flexible since already now daily peak loads exceeding the design load by more then 60% could be treated in the plant without any problems. Compared to other alternatives for the dairy waste water treatment that were investigated during this study, the new side stream process is very advantageous. No other pre-treatment process for industrial waste water could have been operated under comparable loading conditions without severe operating problems.

Suivi du fonctionnement d'une station d'epuration associant physico-chimie et biofiltration = Metabief (France)

1990 ◽  
Vol 22 (1-2) ◽  
pp. 251-259 ◽  
Author(s):  
R. Pujol
Keyword(s):  
Organic Matter ◽  
Biological Process ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Cold Temperatures ◽  
Biological Sludge ◽  
Physico Chemical ◽  
Total Plant ◽  
Sludge Characteristic

The sewage treatment plant of Metabief (East of France) has been monitored during three weeks in winter 1988. The treatment associates a physico-chemical treatment with a biological process of biofiltration. The first step eliminates about 60 % of the organic matter (COD and BOD). The biofliters improve the treatment removing 60 % of COD influent and 65 % of TSS. The process is efficient (N excepted) under conditions of the experiment but nitrification is limited by cold temperatures (< 10°C). Important results related to biological sludge product are presented (sludge characteristic, microscopic data, sludge production). Power consumption of biofliters represents 70 % of the total plant needs. Adequate control of washing cycles and close survey of numerous movable devices are of the utmost importance to guarantee the proper operating of biofliters.

First Practical Experiences with Submerged Rope-Type Bio-Film Reactors for Upgrading and Nitrification

1991 ◽  
Vol 23 (4-6) ◽  
pp. 825-834 ◽  
Author(s):  
T. H. Lessel
Keyword(s):  
Waste Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Waste Water Treatment Plant ◽  
Practical Application ◽  
Reactor Material ◽  
Reactor Materials ◽  
Practical Experiences ◽  
One Year ◽  
Operational Data

The upgrading and nitrification was required for the waste water treatment plant in Geiselbullach. As space for more aeration tanks was not available, the possibility of increasing the MLSS by the use of submerged bio-film reactors was tested in a half technical scale pilot plant with three different reactor materials. Each tested reactor material caused a significant increase of MLSS and the nitrification reaction. The rope-type material was selected for the practical application, as it had not the same disadvantages of the other tested systems, which proved operational problems. After one year of continuous operation for nitrification in the full scale plant the influences on the biomass characteristics were investigated. Design criterias and details and operational data are reported.

Nitrogen Reduction – Volume Demand

1992 ◽  
Vol 25 (4-5) ◽  
pp. 233-240
Author(s):  
T. Palmgren
Keyword(s):  
Suspended Solids ◽  
Age Factors ◽  
Reduction Rate ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Aeration Tank ◽  
Nitrogen Reduction ◽  
Solids Concentration ◽  
Yearly Average ◽  
Nitrification Process

Due to the slow growth of nitrification bacteria at low temperatures, nitrogen reduction normally requires long hydraulic retention time during winter. Important for the nitrification process is the aerated sludge age. Factors influencing the sludge age are aerated volume, mixed liquor suspended solids concentration, organic loading and sludge yield. In an existing plant you cannot easily expand the volume and the load is difficult to decrease. But the suspended solids concentration can be increased by running the biological step with the contact stabilisation process. At the Käppala Association sewage treatment plant in Lidingö just outside Stockholm, one of the six aeration tanks has been reconstructed for full scale nitrogen removal experiments. In this tank the old aeration system has been replaced with rubber membrane diffusers. Further more there are several zones separated by walls in the tank. The tank can thereby be run with great flexibility. By running it with the contact stabilisation process, the sludge age has been improved by a factor between 1.5 and 2 and thereby it succeeds in keeping the nitrification bacteria in the system even during snow melting. At temperatures of about 9 °C and hydraulic retention times of less than 3 hours in the contact zone there has been a nitrification degree of up to 50 to 60 %. The experiment was conducted with a stabilisation zone of up to half the total volume of the aeration tank. The main purpose for the experiments during the winter seasons was to improve nitrification. Keeping the nitrifiers in the system had been a crucial problem during previous years. When the nitrifiers were lost with an increased flow and decreased temperature the nitrification process didn't restart until the temperature was increased and the load decreased. Usually this didn't occur until the middle of the summer meaning a loss of nitrification for up to six months. In Sweden there is a goal set for 50 % nitrogen reduction for the plants in the Stockholm region. At Käppala we manage to keep 60 to 70 % nitrogen reduction during the warm season, that is from July to December. If we can keep up the nitrification the whole year we can achieve 50 % as a yearly average under normal conditions even though we can't keep the nitrogen reduction rate as high during the cold season.

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