0390 - Short-term organic carbon migration from polymeric materials in contact with chlorinated drinking water

To guarantee a good water quality at the consumer’s tap, natural organic matter (NOM) should be (partly) removed during drinking water treatment. The objective of this research is to measure the effect of NOM removal by ion exchange on the biological stability of drinking water. Experiments were performed in two lanes of the pilot plant of Weesperkarspel in the Netherlands. The lanes consisted of ozonation, softening, biological activated carbon filtration and slow sand filtration. Ion exchange in fluidized form was used as pre-treatment in one lane and removed 50% of the dissolved organic carbon (DOC); the other lane was used as reference. Compared to the reference lane, the assimilable organic carbon (AOC) concentration of the finished water in the lane pretreated by ion exchange was 61% lower. The biofilm formation rate of the finished water was decreased with 70% to 2.0 pg ATP/cm2.day. The achieved concentration of AOC and the values of the biofilm formation rate with ion exchange pre-treatment showed that the biological stability of drinking water can be improved by extending a treatment plant with ion exchange, especially when ozonation is involved as disinfection and oxidation step.

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

Water Science & Technology ◽

10.2166/wst.1998.0347 ◽

1998 ◽

Vol 37 (9) ◽

pp. 113-120 ◽

Cited By ~ 6

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.

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

Scientific Reports ◽

10.1038/s41598-021-95015-5 ◽

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.

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

Agronomy ◽

10.3390/agronomy11020348 ◽

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.

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