Treating an aged pentachlorophenol- (PCP-) contaminated soil through three sludge handling processes, anaerobic sludge digestion, post-sludge digestion and sludge land application

2001 ◽  
Vol 44 (10) ◽  
pp. 149-156 ◽  
Author(s):  
S.-T. Chen ◽  
P.M. Berthouex
Keyword(s):  
Contaminated Soil ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Land Application ◽  
Anaerobic Sludge ◽  
Primary Sludge ◽  
Sludge Digestion ◽  
Anaerobic Sludge Digestion ◽  
Soil Cleanup ◽  
Sludge Application

The extensive pentachlorophenol (PCP) contamination and its increasing treatment costs motivate the search for a more competitive treatment alternative. In a municipal wastewater treatment plant, anaerobic sludge-handling processes comprises three bio-processes, namely the anaerobic sludge digestion, post-sludge digestion and sludge land application, which reduce sludge organic content and make sludge a good fertilizer for land application. Availability and effectiveness make the anaerobic sludge handling processes potential technologies to treat PCP-contaminated soil. The technical feasibility of using anaerobic sludge bioprocesses was studied by treating PCP soil in two pilot digesters to simulate the primary sludge digestion, in serum bottles to mimic the post-sludge digestion, and in glass pans to represent the on-site sludge application. For primary digestion, the results showed that up to 0.98 and 0.6 mM of chemical and soil PCP, respectively, were treated at nearly 100% and 97.5% efficiencies. The PCP was transformed 95% to 3-MCP, 4.5% to 3,4-DCP, and 0.5% to 3,5-DCP. For post-digestion, 100% pure chemical PCP and greater than 95% soil PCP were removed in less than 6 months with no chlorophenol residues of any kind. Complete removal of PCP by-products makes this process a good soil cleanup method. For on-site treatment, PCP was efficiently treated by multiple sludge application; however, the PCP residue was observed due to the high initial PCP content in soil. Overall, more mass PCP per unit sludge per day was processed using the primary sludge digestion than the on-site soil treatment or post-sludge digestion. And, sludge acclimation resulted in better PCP treatment efficiencies with all three processes.

Sludge digestion enhancement and nutrient removal from anaerobic supernatant by Mg(OH)2 application

2001 ◽  
Vol 44 (1) ◽  
pp. 161-166 ◽  
Author(s):  
Q. Wu ◽  
P. L. Bishop ◽  
T. C. Keener ◽  
J. Stallard ◽  
L. Stile
Keyword(s):  
Biogas Production ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Ammonia Nitrogen ◽  
Phosphate Removal ◽  
Anaerobic Sludge ◽  
Phosphorus Concentration ◽  
Sludge Stabilization ◽  
Sludge Digestion ◽  
Anaerobic Sludge Digestion

Anaerobic sludge digestion is a widely adopted process for sludge stabilization. Phosphate removal from anaerobic supernatant is necessary to limit the phosphate returned to the head of the treatment plant, thereby improving the overall treatment efficiency. In this study, magnesium hydroxide (Mg(OH)2) was used to improve the sludge digestion efficiency and to remove phosphorus from anaerobic supernatant. The anaerobic sludge digestion experiment was conducted at a pilot scale, and the results showed that applying Mg(OH)2 to anaerobic sludge digester resulted in a larger reduction in SS and COD, a higher biogas production rate, a lower level of phosphate and ammonia nitrogen concentrations in the sludge supernatant and an improved sludge dewaterability. Research results at both lab scale and pilot scale on phosphorus removal from anaerobic supernatant using Mg(OH)2 showed that a high removal of phosphorus can be achieved through the addition of Mg(OH)2. The required reaction time depends on the initial phosphorus concentration and the Mg(OH)2 dosage.

scholarly journals Anaerobic Biodegradability of Agricultural Renewable Fibers

2013 ◽  
Vol 2013 ◽  
pp. 1-3
Author(s):  
Bo Shi ◽  
Peter Lortscher ◽  
Doris Palfery
Keyword(s):  
Wheat Straw ◽  
Municipal Wastewater ◽  
Plant Cell Wall ◽  
Crop Residues ◽  
Natural Fiber ◽  
Anaerobic Sludge ◽  
Agricultural Crop ◽  
Corn Stalk ◽  
Sludge Digestion ◽  
Anaerobic Sludge Digestion

Natural fiber-based paper and paperboard products are likely disposed of in municipal wastewater, composting, or landfill after an intended usage. However, there are few studies reporting anaerobic sludge digestion and biodegradability of agricultural fibers although the soiled sanitary products, containing agricultural fibers, are increasingly disposed of in municipal wastewater or conventional landfill treatment systems, in which one or more unit operations are anaerobic digestion. We conducted a series of biodegradation studies using corn stalk and wheat straw pulp fibers to elucidate biodegradability and biodegradation kinetics under anaerobic sludge digestion conditions. The degradation results indicate that corn stalk achieved 78.4% biodegradation and wheat straw 72.4% biodegradation, all within 56 days of the study. In comparison, corn stalk generated more biogas than wheat straw. Unlike any raw agricultural crop residues, anaerobic biodegradation of agricultural fibers is largely unaffected by the presence of lignin, physical sizes of crop stalks, and plant cell wall constitutes.

Energy self-sufficient sewage wastewater treatment plants: is optimized anaerobic sludge digestion the key?

2013 ◽  
Vol 68 (8) ◽  
pp. 1739-1744 ◽  
Author(s):  
P. Jenicek ◽  
J. Kutil ◽  
O. Benes ◽  
V. Todt ◽  
J. Zabranska ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Energy Consumption ◽  
Anaerobic Digestion ◽  
Biogas Production ◽  
Treatment Plant ◽  
Anaerobic Sludge ◽  
Waste Activated Sludge ◽  
Sludge Digestion ◽  
Anaerobic Sludge Digestion ◽  
Standard Energy

The anaerobic digestion of primary and waste activated sludge generates biogas that can be converted into energy to power the operation of a sewage wastewater treatment plant (WWTP). But can the biogas generated by anaerobic sludge digestion ever completely satisfy the electricity requirements of a WWTP with ‘standard’ energy consumption (i.e. industrial pollution not treated, no external organic substrate added)? With this question in mind, we optimized biogas production at Prague's Central Wastewater Treatment Plant in the following ways: enhanced primary sludge separation; thickened waste activated sludge; implemented a lysate centrifuge; increased operational temperature; improved digester mixing. With these optimizations, biogas production increased significantly to 12.5 m3 per population equivalent per year. In turn, this led to an equally significant increase in specific energy production from approximately 15 to 23.5 kWh per population equivalent per year. We compared these full-scale results with those obtained from WWTPs that are already energy self-sufficient, but have exceptionally low energy consumption. Both our results and our analysis suggest that, with the correct optimization of anaerobic digestion technology, even WWTPs with ‘standard’ energy consumption can either attain or come close to attaining energy self-sufficiency.

Up-to-date modification of the anaerobic sludge digestion process introducing a separate sludge digestion mode

2001 ◽  
Vol 44 (10) ◽  
pp. 143-147 ◽  
Author(s):  
K. Sato ◽  
S. Ochi ◽  
M. Mizuochi
Keyword(s):  
Sewage Treatment ◽  
Anaerobic Sludge ◽  
Advanced Treatment ◽  
Treatment Mode ◽  
Primary Sludge ◽  
Sewage Treatment Plants ◽  
Advantages And Disadvantages ◽  
Digestion Process ◽  
Sludge Digestion ◽  
Anaerobic Sludge Digestion

Sewage treatment plants in Japan are subjected to advanced treatment to remove nutrients and hence control eutrophication problems in lakes and bays. This paper discusses the advantages and disadvantages of the separate digestion treatment mode for sludge generated from advanced wastewater treatment. In the separate digestion only primary sludge is digested and the excess activated sludge is directly dewatered. Separate digestion can reduce the return load of nutrients to approximately one third, and has major potential for the beneficial use of sludge.

Autotrophic nitrogen removal from anaerobic supernatant of Florence's WWTP digesters

2006 ◽  
Vol 53 (12) ◽  
pp. 129-137 ◽  
Author(s):  
S. Caffaz ◽  
C. Lubello ◽  
R. Canziani ◽  
D. Santianni
Keyword(s):  
Nitrogen Removal ◽  
Municipal Wastewater ◽  
Removal Rate ◽  
Treatment Plant ◽  
Experimental Period ◽  
Anaerobic Sludge ◽  
Sludge Digestion ◽  
The One ◽  
Limiting Condition ◽  
Autotrophic Nitrogen Removal

In municipal WWTP with anaerobic sludge digestion, 10–20% of total nitrogen load comes from the return supernatant produced by the final sludge dewatering. In recent years a completely autotrophic nitrogen removal process based on Anammox biomass has been tested in a few European countries, in order to treat anaerobic supernatant and to increase the COD/N ratio in municipal wastewater. This work reports the experimental results of the SHARON-ANAMMOX process application to anaerobic supernatant taken from the urban Florentine area wastewater treatment plant (S. Colombano WWTP). A nitritation lab-scale chemostat (7.4 L) has been started-up seeded with the S. Colombano WWTP nitrifying activated sludge. During the experimental period, nitrite oxidising bacteria wash-out was steadily achieved with a retention time ranging from 1 to 1.5 d at 35 °C. The Anammox inoculum sludge was taken from a pilot plant at EAWAG (Zurich). Anammox biomass has been enriched at 33°C with anaerobic supernatant diluted with sodium nitrite solution until reaching a maximum specific nitrogen removal rate of 0.065 kgN kg−1 VSS d−1, which was 11 times higher than the one found in inoculum sludge (0.005 kgN kg−1VSS d−1). In a lab-scale SBR reactor (4 L), coupled with nitritation bioreactor, specific nitrogen removal rate (doubling time equal to 26 d at 35 °C and at nitrite-limiting condition) reached the value of 0.22 kgN kg−1 VSS d−1, which was approximately 44 times larger than the rate measured in the inoculum Anammox sludge.

scholarly journals THE IMPACT OF CHEMICAL PHOSPHORUS REMOVAL ON THE PROCESS OF ANAEROBIC SLUDGE DIGESTION

2010 ◽  
Vol 2 (5) ◽  
pp. 71-74
Author(s):  
Svetlana Ofverstrom ◽  
Ieva Sapkaitė ◽  
Regimantas Dauknys
Keyword(s):  
Anaerobic Digestion ◽  
Phosphorus Removal ◽  
Biogas Production ◽  
Anaerobic Sludge ◽  
Primary Sludge ◽  
Sludge Digestion ◽  
Volatile Solids ◽  
Anaerobic Sludge Digestion ◽  
Gas Volume ◽  
The Impact

The paper investigates the efficiency of the mixture of primary sludge and excess activated sludge in Vilnius WWTP with reference to the anaerobic digestion process. Sludge digestion was carried out under laboratory conditions using anaerobic sludge digestion model W8 (Armfield Ltd., UK). Laboratory analyses consist of two periods – the anaerobic digestion of the un-dosed and Fe-dosed sludge mixture. The results of digestion were processed using the methods of statistical analysis. The findings showed reduction in volatile solids approx. by 6% when dosing min FeCl3·6H2O and 15% when dosing max FeCl3·6H2O into feed sludge. Gas volume produced during the digestion of the un-dosed sludge was 90–160 ml/d and 60–125 ml/d in min Fe-dosed sludge and 45-95 ml/d. Also, correlation between VS loadings and biogas production was found. A rise in VS loading from 0,64 g/l/d to 1,01 g/l/d increased biogas production from 90 ml/d to 140–160 ml/d.

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