scholarly journals Methane-oxidizing and photoautotrophic bacteria are major producers in a humic lake with a large anoxic hypolimnion

2011 ◽  
Vol 64 (1) ◽  
pp. 81-95 ◽  
Author(s):  
S Taipale ◽  
P Kankaala ◽  
MW Hahn ◽  
RI Jones ◽  
M Tiirola
Keyword(s):  
Humic Lake ◽  
Anoxic Hypolimnion

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.

Air-water interface: dynamics of nutrients and picoplankton in the surface microlayer of a humic lake

1997 ◽  
Vol 26 (2) ◽  
pp. 319-322 ◽  
Author(s):  
Anna Hillbricht-Ilkowska ◽  
Iwona Jasser ◽  
Iwona Kostrzewska-Szlakowska
Keyword(s):  
Surface Microlayer ◽  
Water Interface ◽  
Humic Lake ◽  
Interface Dynamics ◽  
Air Water Interface

Regular high contribution of Gonyostomum semen to phytoplankton biomass in a small humic lake

2002 ◽  
Vol 28 (1) ◽  
pp. 488-491
Author(s):  
Kalevi Salonen ◽  
Anna-Liisa Holopainen ◽  
Jorma Keskitalo
Keyword(s):  
Phytoplankton Biomass ◽  
Humic Lake ◽  
High Contribution ◽  
Gonyostomum Semen

Effects of Experimental Acidification on Phyto-, Bacterio-and Zooplankton in Enclosures of a Highly Humic Lake

1986 ◽  
Vol 71 (6) ◽  
pp. 737-758 ◽  
Author(s):  
Laubi Arvola ◽  
Kalevi Salonen ◽  
Irin A. Bergström ◽  
Anne Heinänen ◽  
Anne Ojala
Keyword(s):  
Humic Lake ◽  
Experimental Acidification

scholarly journals Introduction and Removal of Disinfection Byproducts and Mutagenic Activity by Chemical and Photolytic Treatments

2005 ◽  
Vol 8 (3) ◽  
pp. 387-401 ◽  
Author(s):  
P. Backlund
Keyword(s):  
Carboxylic Acids ◽  
Lake Water ◽  
Mutagenic Activity ◽  
Disinfection Byproducts ◽  
Humic Lake ◽  
River Waters ◽  
Precursor Material ◽  
Strong Mutagen ◽  
Organic Halogens ◽  
Higher Doses

Samples from four different raw water sources were treated with various disinfectants and subjected to chemical analyses and mutagenicity assays. The following disinfectants were used: chlorine (Cl2), chlorine dioxide (ClO2), monochloramine (NH2Cl), ozone (O3), ultraviolet radiation (UV), and combinations of Cl2/ClO2, O3/Cl2, UV/Cl2, and UV/O3/Cl2. The samples were analysed for adsorbable organic halogens (AOX), chloroform (CHCl3), carboxylic acids, volatile organics, chlorite, the strong mutagen 3-chloro-4 (dichloromethyl)-5-hydroxy-2 (5H)-furanone (MX), and mutagenic activity (as detected by the Ames test). Humic lake water which had been treated with the combination UV/Cl2 exhibited a higher level of mutagenicity and higher concentrations of MX and CHCl3 than water treated with Cl2 alone. The same observation was made for the mutagenicity and the CHCl3 concentration in waters preoxidized with low doses of O3 and UV/O3, respectively. When higher doses of these powerful oxidants were used in the pretreatment step, the level of mutagenicity, MX and CHCI3 were lower than in water chlorinated without pretreatment. The combination UV/O3 was found to be more efficient than O3 alone in destroying the precursor material to the mutagenic compounds and chloroform. The higher the proportion of ClO2 in the combined Cl2/ClO2 process, the lower the levels of mutagenicity, MX, CHCl3, and AOX. The production of inorganic chlorite increased with a higher proportion of ClO2. Aldehydes, n-alkanes, and low molecular-weight carboxylic acids were identified as byproducts following UV treatment of humic lake water. The mutagenic activity (per amount of DOC) was approximately similar after chlorination of humic rich surface- and ground waters as after chlorination of waters from the rivers Meuse and Rhine, containing relatively low amounts of humic matter. The precursors to MX were found to be more abundant in the humic waters than in the river waters.

Sign in / Sign up

Export Citation Format

Share Document