Automation and Optimisation of Centrifuge Sludge Dewatering

1989 ◽  
Vol 21 (10-11) ◽  
pp. 1319-1324 ◽  
Author(s):  
Gunter Schrank ◽  
Clive Murren
Keyword(s):  
Continuous Measurement ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Effective Control ◽  
Excess Sludge ◽  
Chemical Additives ◽  
Sludge Dewatering ◽  
Sludge Thickening ◽  
Very High

The dehydration of sewage treatment plant sludges has become one of the major problems in the treatment of waste Water. Very high costs, especially those of flocculation additives, increasingly call for optimisation of this phase of the process. Taking the dewatering of sludge by centrifugation as an example, two different approaches can be considered: mechanical excess sludge thickening without the use of additives and the dehydration of sewage sludge with use of chemical additives. A prerequisite of any automation is the reliable acquisition of data of the parameters required for control. Continuous measurement of the concentration of suspended solids in the sludge that is to be dewatered, of sludge flow and of the turbidity of the clear phase (centrate) leaving the centrifuge, make it possible to design several methods of effective control.

Control of Bulking in an Extended Aeration Sewage Treatment Plant

1972 ◽  
Vol 7 (1) ◽  
pp. 13-20
Author(s):  
D.D.P. Cane ◽  
G.J. Farguhar
Keyword(s):  
Dissolved Oxygen ◽  
Control Measure ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Effective Control ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Mixed Liquor ◽  
Air Supply

Abstract A case of filamentous activated sludge bulking was investigated at an extended aeration plant treating wastes from a highway service centre. The purpose of the study was to find an effective control measure for the bulking and, if possible, to determine the cause of the bulking condition. Experiments were conducted to determine the effects upon bulking of: (a) a controlled copper dosage to the mixed liquor, (b) variations in the organic loading rate, and (c) maintenance of high and low dissolved oxygen concentrations in the mixed liquor. The microorganism responsible for the bulking condition was tentatively identified as Sphaerotilus natans. Extensive growths of these bacteria occurred in the sludge when the mixed liquor dissolved oxygen concentration dropped below 0.5 mg/1. Such dissolved oxygen levels had frequently occurred at this plant due to the use of timed aeration cycles and the use of insufficient air supply during peak loading periods. Variations in organic loading rates were found to have no adverse effect on sludge settleability. When bulking was slight, the condition could be improved by increasing the dissolved oxygen level to 1.5 mg/1, or more. The rate at which the filamentous growths could be eliminated from a highly filamentous sludge by increased aeration was very slow, but could be greatly increased by the simultaneous feeding of copper to the mixed liquor at a dosage rate of 1.0 mg/1, based on the raw sewage flows.

Comparison of lime and alum as oily sludge conditioners

1997 ◽  
Vol 36 (12) ◽  
pp. 117-124 ◽  
Author(s):  
Tay Joo Hwa ◽  
S. Jeyaseelan
Keyword(s):  
Specific Resistance ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Oily Sludge ◽  
Sludge Dewatering ◽  
Capillary Suction ◽  
Sludge Cake ◽  
Solids Content ◽  
Optimum Chemical

Chemical conditioning improves sludge dewatering. Choice of chemical conditioners is very much dependent on the characteristics of the sludges and the type of dewatering devices. Lime, alum, ferric chloride and polyelectrolytes are commonly used chemical conditioners. Anaerobic digested sludge samples collected from a sewage treatment plant with different oil contents varying from 1.8% to 8.0% by weight have been examined in the laboratory to find out their specific resistance, capillary suction time and filter yield. Lime and alum were used separately as conditioners. Different dosages of conditioner varying from 2% to 12% by weight were used to determine the optimum chemical dosage for varying oil contents. Lime dosages of about 6% were found to yield favourable characteristics. Addition of alum decreases the specific resistances and capillary suction times of oily sludges rapidly up to 4% dosages. Alum dosages beyond 4% only increase the solids content in the sludge cake and increase the sludge volume to be handled. A correlation between CST and specific resistance to filtration was established. CST can be measured easily and quickly in the laboratories. Using the CST and the correlation a quick prediction on dewaterability can be established.

Toxicity assays and their evaluation on organic polymer flocculants used for municipal sludge dewatering

1998 ◽  
Vol 38 (7) ◽  
pp. 207-215 ◽  
Author(s):  
H. Takigami ◽  
N. Taniguchi ◽  
Y. Shimizu ◽  
S. Matsui
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Algal Growth ◽  
Pilot Scale ◽  
Organic Polymer ◽  
Municipal Sludge ◽  
Sludge Dewatering ◽  
Algal Toxicity ◽  
Reproduction Tests

The toxicity of organic polymer flocculants used for the dewatering of municipal sludge was evaluated by using two different toxicity assays: the Closterium ehrenbergii algal toxicity test and the Bacillus subtilis rec-assay. The algal toxicity of the effluents from a pilot-scale sewage treatment plant was investigated with and without the addition of a flocculant (0, 0.05, 0.10 and 0.20 mg/L). No clear evidence on the toxicity caused by the flocculant was observed on both asexual and sexual reproduction tests of C. ehrenbergii. It was also found that the algal growth inhibition of various types of flocculants (i.e., cationic, anionic, amphoionic and non-ionic) was in the order of 1 to 20 mg/L, which was mainly due to a molecular weight (MW) fraction of greater than 100,000. The results of the B. subtilis rec-assay for these flocculants indicated that eight out of ten cationic flocculants caused the direct DNA damage with LC50 =0.1 to 10 mg/L. One of the genotoxic flocculants was also fractionated into their components by MW. The experimental results showed that the lethal effects were mainly contributed by the polymer fraction of MW greater than 100,000, although the genotoxicity was not detected in that fraction. Therefore, the detected genotoxicity of the flocculants could be caused by the combined effects of various components, such as polymers, oligomers, monomers and additives.

Control of Heavy Metals and Organochlorines Using the Oil from Sludge Process

1990 ◽  
Vol 22 (12) ◽  
pp. 249-258 ◽  
Author(s):  
T. R. Bridle ◽  
I. Hammerton ◽  
C. K. Hertle
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Control Mechanisms ◽  
Sludge Dewatering ◽  
Water Board ◽  
Unit Operations ◽  
Set Up

A four month pilot plant program, evaluating all unit operations comprising an integrated Oil from Sludge (OFS) plant has been successfully completed for the Sydney Water Board. The unit operations of sludge dewatering, drying and conversion to oil in the patented OFS reactor system were set up at the Malabar Sewage Treatment Plant in Sydney. Pilot testing of the char combustor was conducted off site. Extensive heavy metal and organochlorine monitoring across each unit operation has revealed the following information. There is no loss of contaminants across the dewatering and drying operations. With the exception of arsenic and mercury, all heavy metals fed to the OFS reactor are retained in the char. Greater than 75% of PCB's and 85% of HCB present in sludge are destroyed in the OFS reactor. Greater than 99.7% of the heavy metals fed to the fluid bed combustor are retained in the ash (with exception of mercury, which reported 3% in the flue gas). The FBC ash is classified non-hazardous, using the Toxic Characteristic Leaching Procedure.No organochlorines were detected in the dryer or FBC off-gases. The OFS technology offers decoupling of heavy metal and organochlorine control mechanisms, thus allowing each to be optimally controlled.

Wastewater quality relationships with reuse options

2001 ◽  
Vol 43 (10) ◽  
pp. 147-154 ◽  
Author(s):  
R. A. Patterson
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Chemical Properties ◽  
Oxygen Demand ◽  
Land Application ◽  
Chemical Additives ◽  
Beneficial Effects ◽  
Wastewater Quality ◽  
Reuse Options

The trend towards reuse of effluent for land application of domestic and industrial wastewater is driven by the need to maximise limited water resources and benefit from the plant nutrients available in the effluent. Of significant impact upon the value of the wastewater for reuse is its chemical properties as well as biochemical oxygen demand and suspended solids. While the sewage treatment plant is expected to treat all wastewater received to a minimum environmental standard, no efforts are given to reducing the chemical load derived from uses of chemicals in the domestic household. That the regulation of industry and commerce far exceeds those of the combined effects of thousands of household is remiss of environmental regulators. This paper examines the results of research into the more common sources of chemical additives to the wastewater stream. Twenty five potable water supplies are examined for their salt load, 20 liquid and 40 powder laundry detergents and five dishwashing products were used to simulate discharges to the sewer, measured for their phosphorus, salt and sodium concentrations. The results of the research indicate that choices in the products available for general use within the house can be made only where product labelling and consumer education is improved. Technical improvements in wastewater treatment are not the answer. The improvement in effluent quality will have significant beneficial effects upon land application areas and expand the range of reuse options available for commercial operations.

scholarly journals Study on recovery of biogas from mixed biowaste for regional biogasification system

2019 ◽  
pp. 89-98
Author(s):  
Toshihiro Komatsu ◽  
Rokuta Inaba ◽  
Tohru Furuichi ◽  
Norio Nishi ◽  
Noboru Tanikawa
Keyword(s):  
Electric Power ◽  
Co2 Emission ◽  
Energy Recovery ◽  
Organic Waste ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
The One ◽  
Carbon Dioxide Co2 ◽  
Very High

Even in Japan, the energy recovery from a waste became the importance by not only wastetreatment problem but also environmental problem which carbon dioxide (CO2) causes. Theenergy recovery is being measured from organic waste. However, the construction of thedisposing facility does not advance in actually various factors. As the one factor, the property ofa organic waste variously changes by the discharge source such as home, food shop, supermarket, farm, sewage treatment plant, etc., and the energy recovery ratio changes with it. In thisstudy, the biogas generation of the waste which arose actually was obtained experimentally. Inaddition, the following were examined using waste generation in the region and the biogas frombiowaste : Electric power recovery, heat recovery, CO2 emission. In the garbage discharged, thegas generation magnification showed the very high, The gas yields seemed to be very high forbiowastes, since these is originally offered as foods. In case of the livestock manure, the gasyield over about 16 times per manure was obtained. The gas yield is not very dependent on theorganic substance content. This cause the bedding was included in the manure, and it seemed toaffect the organic substance content by the content and type. In case of the sewage sludge, thegas yield of about 3.5 times per sludge was got. As a result of the trial based on the wastegeneration in the region, electric power, heat can be utilized effectively. In addition, that thereduction was also possible on CO2 emission clarified.

Nutrient Removal in a 2-Stage Biological Sewage Treatment Plant

1992 ◽  
Vol 25 (4-5) ◽  
pp. 135-142
Author(s):  
E. Sickert
Keyword(s):  
Nutrient Removal ◽  
Combined Treatment ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Distribution Channel ◽  
Operating Conditions ◽  
Phosphorus Concentration ◽  
Legal Regulations ◽  
Excess Sludge

The Dradenau sewage treatment plant consists basically of a large activated sludge plant which supplements the treatment stages of the Köhlbrandhöft plant. Although built to mainly oxidize ammonia and despite unfavourable operating conditions - the different locations of the Köhlbrandhöft and Dradenau plants - considerable amounts of nitrogen have successfully been eliminated. Denitrification takes place in the distribution channel of the Dradenau plant and in one of the biological stages of the Köhlbrandhöft plant. This stage takes over the excess sludge from the Dradenau plant resulting in nitrifying - and denitrifying - part of the nitrogen load already here. There is an average overall reduction of 70 %. Simultaneous precipitation at the Köhlbrandhöft treatment plant reduces the phosphorus concentration in the effluent of the combined treatment plants Köhlbrandhöft/Dradenau to values recently set by legal regulations (1 mgP/l).

scholarly journals Application of excess sludge extract from sewage treatment plant in garden flower planting

2020 ◽  
Vol 546 ◽  
pp. 032025
Author(s):  
Lifang Cui ◽  
Cheng Yang ◽  
Aiai Yang ◽  
Yan Sun ◽  
Fanfei Meng ◽  
...  
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Excess Sludge

Chemical Removal and Recovery of Phosphorus from Excess Sludge in a Sewage Treatment Plant

2006 ◽  
Vol 27 (5) ◽  
pp. 501-510 ◽  
Author(s):  
K. Kato ◽  
N. Murotani ◽  
H. Matsufuji ◽  
M. Saitoh ◽  
Y. Tashiro
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Excess Sludge ◽  
Removal And Recovery

scholarly journals Stability Analysis of Mechanical Sludge Dewatering Machine Frame Based on Numerical Simulation

2022 ◽  
Vol 2152 (1) ◽  
pp. 012047
Author(s):  
Li Chen
Keyword(s):  
Equivalent Stress ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Normal Operation ◽  
Motor Speed ◽  
Sludge Dewatering ◽  
Element Analysis ◽  
Operation Conditions ◽  
Interference Frequency

Abstract Sludge is the inevitable product of sewage treatment plant and sewage treatment. Before sludge treatment, dewatering is generally required. Mechanical sludge dewatering machine is a common sludge dewatering equipment. Due to the complex operation conditions, the stability of sludge dewatering machine frame directly affects its reliability. In this paper, a mechanical sludge dewatering machine frame as the research object, based on ANSYS Workbench finite element analysis platform, static analysis and modal analysis. The analysis results show that: under normal working conditions, the maximum variable of the frame is 0.07mm, which can effectively ensure the normal operation of the sludge dewatering machine; the equivalent stress is 4.22Mpa, which is far less than the Xu Yong stress of the material; the vibration of the first two modes of the frame is relatively concentrated, and the corresponding motor speed under the interference frequency is 1241.4-1595.4r/min, which should be avoided in the use process.

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