238 Organic compounds in soils, sediments & sludges
André et al [193] discuss the determination of adenosine-5
triphosphate by
luciferin-luciferase assay. This method was applied to the determination of adenosine5
-triphosphate in bacterial colonies filtered from samples of polluted water after
incubation for different periods. The adenosine-5
-triphosphate was extracted from
the residue in the filter and the amount compared with the biochemical oxygen demand
of the filtered water. The oxygen uptake rate and the rate of formation of adenosine5
triphosphate were then plotted against time, the two curves being similar in up
to three to four days’ incubation, after which adenosine-5
triphosphate production
declined markedly, although oxygen uptake continued to increase.
Hysert et al [194, 195] state that the firefly bioluminescence adenosine-5
-
triphosphate assay has several attractive features including high sensitivity, selectivity
and freedom from sample interferences. The high assay sensitivity permitted very high
sample dilutions thus further reducing the possibility of interference and/or inhibition
of the bioluminescent reaction by sample components [195–197].
These workers [194] demonstrated that interference and inhibition of the bioluminescence assay by extract components was negligible by a standard adenosine5
-triphosphate method [197]. This circumstance undoubtedly resulted from the
aforementioned high extract dilution as well as from the use of purified luciferase.
Miscellaneous
Higgins et al [198] has compared four methods of extracting adenosine-5
-triphosphate
using activated sludge samples from the aeration basin: dilution with cold nitric acid
and extraction with cold Tris buffer; dilution with distilled water and extraction with
cold nitric acid; dilution with distilled water followed by extraction with boiling Tris
buffer; and extraction using a nucleotide releasing agent for bacteria. This releasing agent only extracted 32% of the adenosine-5
triphosphate that was extracted
using boiling Tris buffer; the other two methods were slightly less efficient than the
boiling Tris buffer, but not significantly so. The uncomplicated extraction with cold
nitric acid was suitable for use on-site. Adenosine-5
-triphosphate levels in activated
sludge dropped by 25% during the first hour after collection so it was important that
adenosine-5
triphosphate was extracted on site. Extracts were stable for at least 7
hours. There was no significant difference in the adenosine-5
triphosphate content
between activated sludge samples collected at four different sites in an aeration basin.
10.8.4 Humic and fulvic acids
Rebhun and Mouka et al [199, 200] have reported that about 40–50% of the organics in secondary sewage effluents constitute humic substances, the remainder being
anionic detergents, carbohydrates, proteins, tannins, lignins and ether extractables.
They extended this work [200] to a more detailed examination of the humic substances
in secondary effluents obtained from high-rate trickling filters, and the effluents from
a stabilisation pond and from an extended aeration activated sludge plant.
The investigation of humic substances included examination of their infrared spectrum, determination of carboxylic and phenolyhydroxlic functional acidic groups,
and estimation of their molecular weight distribution. The humic substances isolated
from secondary effluents were further divided into humic, hymathomelanic and fulvic
acids. The humic and hydmathomelanic fractions were then dissolved in 0.5 M sodium
André et al [193] discuss the determination of adenosine-5
triphosphate by
luciferin-luciferase assay. This method was applied to the determination of adenosine5
-triphosphate in bacterial colonies filtered from samples of polluted water after
incubation for different periods. The adenosine-5
-triphosphate was extracted from
the residue in the filter and the amount compared with the biochemical oxygen demand
of the filtered water. The oxygen uptake rate and the rate of formation of adenosine5
triphosphate were then plotted against time, the two curves being similar in up
to three to four days’ incubation, after which adenosine-5
triphosphate production
declined markedly, although oxygen uptake continued to increase.
Hysert et al [194, 195] state that the firefly bioluminescence adenosine-5
-
triphosphate assay has several attractive features including high sensitivity, selectivity
and freedom from sample interferences. The high assay sensitivity permitted very high
sample dilutions thus further reducing the possibility of interference and/or inhibition
of the bioluminescent reaction by sample components [195–197].
These workers [194] demonstrated that interference and inhibition of the bioluminescence assay by extract components was negligible by a standard adenosine5
-triphosphate method [197]. This circumstance undoubtedly resulted from the
aforementioned high extract dilution as well as from the use of purified luciferase.
Miscellaneous
Higgins et al [198] has compared four methods of extracting adenosine-5
-triphosphate
using activated sludge samples from the aeration basin: dilution with cold nitric acid
and extraction with cold Tris buffer; dilution with distilled water and extraction with
cold nitric acid; dilution with distilled water followed by extraction with boiling Tris
buffer; and extraction using a nucleotide releasing agent for bacteria. This releasing agent only extracted 32% of the adenosine-5
triphosphate that was extracted
using boiling Tris buffer; the other two methods were slightly less efficient than the
boiling Tris buffer, but not significantly so. The uncomplicated extraction with cold
nitric acid was suitable for use on-site. Adenosine-5
-triphosphate levels in activated
sludge dropped by 25% during the first hour after collection so it was important that
adenosine-5
triphosphate was extracted on site. Extracts were stable for at least 7
hours. There was no significant difference in the adenosine-5
triphosphate content
between activated sludge samples collected at four different sites in an aeration basin.
10.8.4 Humic and fulvic acids
Rebhun and Mouka et al [199, 200] have reported that about 40–50% of the organics in secondary sewage effluents constitute humic substances, the remainder being
anionic detergents, carbohydrates, proteins, tannins, lignins and ether extractables.
They extended this work [200] to a more detailed examination of the humic substances
in secondary effluents obtained from high-rate trickling filters, and the effluents from
a stabilisation pond and from an extended aeration activated sludge plant.
The investigation of humic substances included examination of their infrared spectrum, determination of carboxylic and phenolyhydroxlic functional acidic groups,
and estimation of their molecular weight distribution. The humic substances isolated
from secondary effluents were further divided into humic, hymathomelanic and fulvic
acids. The humic and hydmathomelanic fractions were then dissolved in 0.5 M sodium