A three-stage biofiltration process: performances of a pilot plant

1998 ◽  
Vol 38 (8-9) ◽  
pp. 257-265
Author(s):  
P. Chudoba ◽  
R. Pujol
Keyword(s):  
Organic Carbon ◽  
Flow Rate ◽  
Pilot Plant ◽  
Applied Load ◽  
Municipal Wastewater ◽  
Bacterial Species ◽  
Normal Operation ◽  
Organic Load ◽  
Short Term ◽  
Final Effluent

A three-stage biological aerated filter (BAF) pilot plant has been run, fed with a mechanically pre-treated municipal wastewater. The pilot plant consisted of a physico-chemical lamella sedimentation unit for suspended solids removal and soluble phosphorus precipitation, followed by three stages of up-flow biofilters: a BAF C for organic carbon removal, a BAF N for nitrification and a biological anoxic filter (BaF DN) for post-denitrification with methanol as an external organic carbon source. The main objective of the experiments was to study the process limits of this pilot plant under overloading conditions, and to evaluate the time necessary for recovery of normal operation after a period of strong overloading. The pilot plant was first operated at a nominal wastewater flow rate of 12 m3/h (according to previous conventional design rules for first generation of up-flow BAF), which was progressively increased up to 25 m3/h, a maximum value still enabling us to achieve the final effluent standards. Beyond this flow rate, a high organic carbon load applied to the BAF C was only partially removed by this filter, the rest had to be eliminated in the BAF N unit. Consequently, the factor directly limiting the tested pilot plant was the COD overloading of the BAF C, which indirectly influenced the nitrification in the BAF N. The maximum applied load eliminated by the pilot plant, at a wastewater flow rate of 25 m3/h, was 2 times higher than the nominal applied load at a wastewater flow rate of 12 m3/h. In the second experimental period, short-term strong overloadings were applied to the pilot plant operating in steady state conditions at a nominal flow rate, and the limiting process parameters were detected. A lower short-term overloading (32 m3/h = 2.66 times the nominal flow rate) had no effect on the quality of the final effluent, and different filters were able to remove short-term loadings as high as 25 kg COD/m3.d (BAF C), 1.6 kg NH4-N/m3.d (BAF N) and 3.2 kg NO3-N/m3.d (BaF DN). These loadings represent respectively 1.33 times the maximum applied load found in the first set of experiments and 2.66 times the nominal load at a wastewater flow rate of 12 m3/h. A higher short-term overloading (40 m3/h = 3.33 times the nominal flow rate) led to the same consequences as in the first period: a high organic load (up to 32 kg COD/m3.d for the BAF C) was partially removed in the BAF N, decreasing thus its nitrification capacity. The recovery of normal operation after the period of overloading was almost immediate. This study showed that it is very important to maintain the specific populations in separate reactors, in order to reduce the competition between different bacterial species and to enable the microorganisms to grow under optimal conditions. The tested treatment configuration is particularly suited for treating peak flow with high removal rates.

Increasing the capacity for treatment of chemical plant wastewater by replacing existing suspended carrier media with Kaldnes Moving Bed(tm) media at a plant in Singapore

2004 ◽  
Vol 49 (11-12) ◽  
pp. 199-205 ◽  
Author(s):  
F.G. Wessman ◽  
E. Yan Yuegen ◽  
Q. Zheng ◽  
G. He ◽  
T. Welander ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Activated Sludge ◽  
Normal Operation ◽  
Organic Load ◽  
Moving Bed ◽  
Biofilm Carrier ◽  
L 51 ◽  
Biofilm Process ◽  
Suspended Carrier ◽  
Final Effluent

The Kaldnes biomedia K1, which is used in the patented Kaldnes Moving Bed(tm) biofilm process, has been tested along with other types of biofilm carriers for biological pretreatment of a complex chemical industry wastewater. The main objective of the test was to find a biofilm carrier that could replace the existing suspended carrier media and at the same time increase the capacity of the existing roughing filter-activated sludge plant by 20% or more. At volumetric organic loads of 7.1 kg COD/m3/d the Kaldnes Moving Bed™ process achieved much higher removal rates and much lower effluent concentrations than roughing filters using other carriers. The Kaldnes roughing stage achieved more than 85% removal of organic carbon and more than 90% removal of BOD5 at the tested organic load, which was equivalent to a specific biofilm surface area load of 24 g COD/m2/d. Even for the combined roughing filter-activated sludge process, the Kaldnes carriers outperformed the other carriers, with 98% removal of organic carbon and 99.6% removal of BOD5. The Kaldnes train final effluent concentrations were only 22 mg FOC/L and 7 mg BOD5/L. Based on the successful pilot testing, the full-scale plant was upgraded with Kaldnes Moving Bed™ roughing filters. During normal operation the upgraded plant has easily met the discharge limits of 100 mg COD/L and 50 mg SS/L. For the month of September 2002, with organic loads between 100 and 115% of the design load for the second half of the month, average effluent concentrations were as low as 9 mg FOC/L, 51 mg COD/L and 12 mg SS/L.

scholarly journals Hexavalent chromium removal from municipal wastewater using ferrous salts

2018 ◽  
Vol 13 (1) ◽  
pp. 115-124
Author(s):  
Benjamin David Martin ◽  
Mohammed Qasim Asghar ◽  
Eve Germain
Keyword(s):  
Hexavalent Chromium ◽  
Municipal Wastewater ◽  
Aquatic Toxicity ◽  
Sewage Treatment ◽  
Chromium Concentration ◽  
Organic Load ◽  
Ferrous Chloride ◽  
Water Courses ◽  
Study Laboratory ◽  
Final Effluent

Abstract Hexavalent chromium is difficult to remove during conventional biological wastewater treatment. This is because the hexavalent form is dissolved and is only sparingly removed by adsorption onto biomass in conventional processes. Hexavalent chromium is of particular concern because of its aquatic toxicity, and an increasing number of wastewater works have effluent discharge limits to protect receiving water courses, some as low as 8 μg Cr L−1. A relatively simple improvement to the removal of chromium could be made by switching the aluminium or ferric solution dosed at most treatment works for the removal of solids, organic load and phosphorus, to a ferrous salt. Ferrous reduces hexavalent chromium to insoluble trivalent chromium, which can be readily settled out of waste streams as a particulate. In the present study, laboratory experiments using real wastewater and ferrous doses of 10 mg Fe L−1 achieve the chromium discharge consent of 8 μg L−1 from initial solution concentrations of up to 40 μg L−1. A ferrous chloride dosing system was subsequently installed at an operational sewage treatment works that has produced an average final effluent chromium concentration of 2.4 μg L−1 (with a maximum of 4.2 μg L−1), despite influent spikes >300 μg L−1.

A study about the use of chemicals in conventional tertiary treatment. Performances comparison of three municipal wastewater treatment plants and pilot plant experiences

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
A. Iborra-Clar ◽  
J.A. Mendoza-Roca ◽  
A. Bes-Pií ◽  
J.J. Morenilla-Martínez ◽  
I. Bernácer-Bonora ◽  
...  
Keyword(s):  
Water Quality ◽  
Wastewater Treatment ◽  
Pilot Plant ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Secondary Effluent ◽  
Municipal Wastewater Treatment ◽  
Wastewater Reclamation ◽  
Valencian Region ◽  
Municipal Wastewater Treatment Plants

Rainfall diminution in the last years has entailed water scarcity in plenty of European regions, especially in Mediterranean areas. As a consequence, regional water authorities have enhanced wastewater reclamation and reuse. Thus, the implementation of tertiary treatments has become of paramount importance in the municipal wastewater treatment plants (WWTP) of Valencian Region (Spain). Conventional tertiary treatments consist of a physico-chemical treatment of the secondary effluent followed by sand filtration and UV radiation. However, the addition of coagulants and flocculants sometimes does not contribute significantly in the final water quality. In this work, results of 20-months operation of three WWTP in Valencian Region with different tertiary treatments (two without chemicals addition and another with chemicals addition) are discussed. Besides, experiments with a 2 m3/h pilot plant located in the WWTP Quart-Benager in Valencia were performed in order to evaluate with the same secondary effluent the effect of the chemicals addition on the final water quality. Results showed that the addition of chemicals did not improve the final water quality significantly. These results were observed both comparing the three full scale plants and in the pilot plant operation.

Distribution of heterotrophic and autotrophic organisms in a biological aerated filter

2008 ◽  
Vol 3 (3) ◽  
Author(s):  
O. González-Barceló ◽  
S. González-Martínez
Keyword(s):  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Low Cost ◽  
Ammonia Nitrogen ◽  
Organic Load ◽  
Homogeneous Distribution ◽  
Municipal Wastewater Treatment ◽  
Filter Media ◽  
Aerated Filter ◽  
Secondary Settling

Biological aerated filtration is a viable option for small municipal wastewater treatment plants. A low cost filter media was obtained by triturating volcanic rock. An apparent porosity of 46 % and a specific surface area of 395 m2/m3·d were obtained once the filter was packed by using a grain size of 8.2 mm. The performance of the system, operated as a biological filter, was evaluated under an average organic load of 2.6±0.4 kgCODT/m3·d (6.7±1.1 gCODT/m2·d) without primary and secondary settling. The average CODT decreased from 220 mg/l in the influent to 88 mg/l in the effluent and the CODD was decreased from 148 mg/l in the influent to 50 mg/l in the effluent. The filter media, in combination with the biofilm, allowed a 75 % TSS removal. The ammonia nitrogen decreased from 51 mg/l in the influent to 33 mg/l in the effluent. The maximum flux coefficients of 9.3gCODdissolved/m2·d and 2.9gNH4-N/m2·d at the biofilm surface were used to simulate, with the Michaelis-Menten model, the profiles of dissolved COD, ammonium and nitrates through the aerated filter. It was possible to conclude that the backwashing procedure removed the excess biomass and was responsible for a homogeneous distribution of heterotrophic and autotrophic microorganisms along the filter depth.

Parameters for Measuring the Activity and Viability of Activated Sludge

1974 ◽  
Vol 9 (1) ◽  
pp. 235-249 ◽  
Author(s):  
S.G. Nutt ◽  
K.L. Murphy
Keyword(s):  
Organic Carbon ◽  
Activated Sludge ◽  
Biological System ◽  
Analytical Methods ◽  
Heterogeneous System ◽  
Removal Rate ◽  
Bacterial Species ◽  
Atp Content ◽  
Culture Studies ◽  
Activated Sludge System

Abstract Conventional wastewater parameters are accepted as inadequate estimates of the condition of activated sludge but numerous other indices have been suggested as specific measurements of the activity and viability of the biomass. Literature in the related fields of microbiology and biochemistry were reviewed in order to select the most appropriate activity parameters for application to a heterogeneous biological material. Modified analytical methods were applied to a well-controlled biological system containing a single predominant bacterial species to evaluate the relative merit of each as an indicator of viability and activity. The potential of each parameter in a complex heterogeneous system was determined by monitoring each index in a bench activated sludge system. The predominant culture studies indicated that the ATP content of the biomass and the dehydrogenase activity were potential indicators of cell viability in a simple system. However, in the complex activated sludge system, only the ATP content showed significant correlation to the organic carbon removal rate.

Evaluating ozone dose for AOC removal in two-step GAC filters

1998 ◽  
Vol 37 (9) ◽  
pp. 113-120 ◽  
Author(s):  
R. Vahala ◽  
T. Ala-Peijari ◽  
J. Rintala ◽  
R. Laukkanen
Keyword(s):  
Activated Carbon ◽  
Organic Carbon ◽  
Second Step ◽  
Humic Lake ◽  
Short Term ◽  
Feasible Method ◽  
Assimilable Organic Carbon ◽  
Water Treatment Plants ◽  
Ozone Dose ◽  
Ozonated Water

Upgrading an existing post-ozonation plant with two-step granular activated carbon (GAC) filtration for assimilable organic carbon (AOC) removal was studied. The effects of ozone dose on AOC formation and its removal in the subsequent two-step GAC filtration was studied using chemically pretreated 2 to 14° C humic lake water. Two parallel pilot-plant trains with different ozone doses (0 to 1.2 mgO3/mgTOC) and a short-term ozonation study were performed. The optimum ozone dose for maximum AOC formation was 0.4–0.5 mgO3/mgTOC. The AOC-P17 of ozonated water was three-fold higher and AOC-NOX over ten-fold higher than in non-ozonated water, while the following biofiltration (first step) removed 51% and 72% of AOC-P17 and AOC-NOX, respectively. The adsorber (second step) contributed to less than 10% of the overall AOC reduction. It appeared that biofiltration is a feasible method in upgrading water treatment plants for AOC removal even when treating cold humic waters, while the subsequent adsorber seems to have less significance for AOC removal.

scholarly journals Effects of different returning method combined with decomposer on decomposition of organic components of straw and soil fertility

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiao Wang ◽  
Xuexin Wang ◽  
Peng Geng ◽  
Qian Yang ◽  
Kun Chen ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Fertility ◽  
Decomposition Rate ◽  
Microbial Biomass Carbon ◽  
No Tillage ◽  
Short Term ◽  
Straw Decomposition ◽  
Short Period ◽  
Straw Return ◽  
Forms Of Carbon

AbstractIn view of the problems of low straw decomposition rates and reduced soil fertility in southern Liaoning, China, we investigated the effects of no-tillage mode (NT), deep loosening + deep rotary tillage mode (PT), rotary tillage mode (RT) and the addition of decomposing agent (the next is called a decomposer) (NT + S, PT + S, RT + S) on the decomposition proportion of straw, respectively, by using the nylon net bag method in combination with 365-day field plot experiments. The decomposition rules of cellulose, hemicellulose and lignin as well as the dynamics of soil organic carbon (SOC), soil microbial biomass carbon (MBC) and soil dissolved organic carbon (DOC) in straw returned to the field for 15, 35, 55, 75, 95, 145 and 365 days were analyzed. The results showed that in the short term, the decomposition of straw was better in both the rotray tillage and deep loosening + deep rotary modes than in the no-tillage mode, and the addition of decomposer significantly promoted the decomposition of straw and the release of carbon from straw, among them, the RT + S treatment had the highest straw decomposition proportion and carbon release proportion in all sampling periods. After a one year experimental cycle, the RT + S treatment showed the highest proportion of cellulose, hemicellulose and lignin decomposition with 35.49%, 84.23% and 85.50%, respectively, and soil SOC, MBC and DOC contents were also higher than the other treatments with an increase of 2.30 g kg−1, 14.22 mg kg−1 and 25.10 mg kg−1, respectively, compared to the pre-experimental soil. Our results show that in the short term, to accelerate the decomposition rate of returned straw and increase the content of various forms of carbon in soil, rotary tillage can be used to return the straw to the field, while also spraying straw decomposer on its surface. This experiment used a new straw decomposer rich in a variety of microorganisms, combined with the comparison of a variety of straw return modes, and in-depth study of straw decomposition effects of cellulose, hemicellulose and lignin. Thus, a scheme that can effectively improve the decomposition rate of straw and the content of various forms of organic carbon in soil within a short period of time was explored to provide theoretical support for the southern Liaoning.

scholarly journals Site-Specific Effects of Organic Amendments on Parameters of Tropical Agricultural Soil and Yield: A Field Experiment in Three Countries in Southeast Asia

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 348
Author(s):  
Thuy Thu Doan ◽  
Phimmasone Sisouvanh ◽  
Thanyakan Sengkhrua ◽  
Supranee Sritumboon ◽  
Cornelia Rumpel ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Southeast Asia ◽  
Biomass Production ◽  
Nutrient Availability ◽  
Organic Amendments ◽  
Water Infiltration ◽  
Elemental Content ◽  
Soil Parameters ◽  
Short Term ◽  
Site Specific

Organic amendments may improve the quality of acidic tropical agricultural soils with low organic carbon contents under conventional management (mineral fertilization and irrigation) in Southeast Asia. We investigated the effect of biochar, compost and their combination on maize growth and yield, soil physical, biological and chemical properties at harvesting time at four sites in three countries: Thailand, Vietnam and Laos. Treatments consisted of 10 t·ha−1 cow manure compost and 7 t·ha−1 of Bamboo biochar and their combination. Maize biomass production and cop yields were recorded for two seasons. Elemental content, pH and nutrient availability of soils were analyzed after the first growing season. We also characterized macrofauna abundance and water infiltration. Few changes were noted for maize biomass production and maize cop yield. Soil chemical parameters showed contrasting, site-specific results. Compost and biochar amendments increased soil organic carbon, pH, total K and N, P and K availability especially for sandy soils in Thailand. The combination of both amendments could reduce nutrient availability as compared to compost only treatments. Physical and biological parameters showed no treatment response. We conclude that the addition of compost, biochar and their mixture to tropical soils have site-specific short-term effects on chemical soil parameters. Their short-term effect on plants is thus mainly related to nutrient input. The site-dependent results despite similar crops, fertilization and irrigation practices suggest that inherent soil parameters and optimization of organic amendment application to specific pedoclimatic conditions need future attention.

scholarly journals Stover management modifies soil organic carbon dynamics in the short-term under semiarid continuous maize

2021 ◽  
Vol 213 ◽  
pp. 105143
Author(s):  
Jorge Álvaro-Fuentes ◽  
Samuel Franco-Luesma ◽  
Victoria Lafuente ◽  
Pablo Sen ◽  
Asun Usón ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Dynamics ◽  
Short Term ◽  
Continuous Maize ◽  
Soil Organic Carbon Dynamics
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