Improvements in the Recovery of Ammonia from Sewage Effluent and other Weak Ammoniacal Liquors.
Year: 1895

page_text: Date of Application, 6th Feb.,
4005
Complete Specification Left, 6th Nov., 1895-Accepted, 7th Dec., 1895
Complete Specification Left, 6th Nov., 1895-Accepted, 7th Dec., 1895
PROVISIONAL SPECIFICATION.
Improvements in the Recovery of Ammonia from Sewage Effluent
and other Weak Ammoniacal Liquors.
We, THOMAS TWYNAM of Elmhurst, Egham, in the County of Surrey,
Analytical Chemist, and FRANCIS EDWARD MATTHEWS, of The Pines, Englefield
Green in the County of Surrey, Demonstrator in Chemistry, do hereby declare the
nature of this invention to be as follows:-
Our invention relates to an improved process for the recovery of ammonia from
weak ammoniacal solutions and is especially applicable to the recovery of ammonia
from sewage effluent, which contains on an average from 5 to 10 parts of ammonia
in 100,000 parts of solution.
We find that some oxides in the free state or when in combination with phos-
phoric acid, and in an hydrated condition, have the property of absorbing ammonia
from weak solutions, and that the ammonia thus absorbed may be removed from
time to time as the hydrate or phosphate becomes feebler in its action towards the
ammoniacal solution.
For our purpose we find that the perphosphate of iron and the hydrated peroxide
of iron are the most suitable. The phosphate of tin also gives very good results,
and in a less degree the hydrated oxide & phosphate of zinc.
.
We apply this reaction in practice by filtering the weak ammoniacal solution
through a filter composed of the hydrated oxide or phosphate which may be
previously mixed with sand to increase the rate of flow if desired. We prefer to
have the filter contained in an iron or earthenware jacket and to have filters
arranged in series so that when one is saturated another may be at once started;
the flow of effluent being thus maintained continuously.
When the filter has taken up as much ammonia as the material employed will
absorb, a current of hot air, steam, or heated carbonic acid is forced through it, by
which means the ammonia is driven off & may be condensed in the usual way; the
filter may be then again put into use. Any other convenient way of driving off the
ammonia by means of heat or otherwise may be employed.
In some cases
(especially with a phosphate filter) we employ the material after absorbtion of
ammonia directly as a fertilizing material.
Dated this 2nd day of February 1895.
Improvements in the Recovery of Ammonia from Sewage Effluent
and other Weak Ammoniacal Liquors.
We, THOMAS TWYNAM of Elmhurst, Egbam, in the County of Surrey,
Analytical Chemist, and FRANCIS EDWARD MATTHEWS of The Pines, Englefield
Green in the County of Surrey, Demonstrator in Chemistry do hereby declare
the nature of this invention and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement :-
Our invention relates to an improved process for the elimination and recovery of
[Price 8a l

page_text: ammonia from weak ammoniacal solutions, and is especially applicable to the
recovery of ammonia from sewage effluent, which contains on an average from 5 to
10 parts of ammonia in 100,000 parts of solution.
We find that some hydrated oxides, when in combination with phosphoric acid
have the property of absorbing ammonia from weak solutions containing ammonia
either in the free state or in combination with carbonic acid, and that the ammonia
thus absorbed may be removed from time to time as the material used as a filter
becomes feebler in its action towards the ammoniacal solution.
For use in practical working we find that a mixture of the perphosphate and
hydrate of iron is the most suitable, and we find such a material in Nature in the
form of hydrated iron ore fairly high in phosphoric acid. Other materials however,
such as the phosphate of tin also give very good results, but from the ease with
which it may be obtained we prefer the ferruginous material.
We apply the reaction in practice by filtering the weak ammoniacal solution
through a filter composed of the above material, which may however be mixed with
some inert substance to increase the rate of flow.
The filtering material may be conveniently surrounded by a hollow metallic
jacket so that, when required, it may be heated by steam or hot air so as to expel
the ammonia, or steam pipes may be laid in the filtering material in any convenient
manner, or hot air or steam may be drawn through the material of the filter. The
filters may be arranged in series so that when one is saturated another may be at
once started, the flow of effluent being thus maintained continuously.
We prefer the sewage effluent should be as free as possible from suspended
matter, which would if admitted ultimately choke the filter; to avoid this we
sometimes make the bottom part only of the filters of our material, the upper
part being some inert material, which serves to retain the suspended matter.
When the filter has taken up as much ammonia as the material will absorb, the
stream of effluent is turned off, and, when the filter has drained, the ammonia is
driven off by means of heat or otherwise and condensed in the usual way. In some
cases we employ the material after absorption of ammonia directly as a fertilizer,
it being of value both for the phosphoric acid and ammonia contained in it. We
sometimes recover the ammonia by passing weak acid solutions directly through the
filter.
Having now particularly described & ascertained the nature of our said inven-
tion, & in what manner the same is to be performed we declare that what
we claim is;-
1. The elimination & recovery of ammonia from sewage effluent or other weak
ammoniacal solution by filtering it through a mixture of the hydrate & phosphate of
iron or other suitable hydrate & phosphate, & afterwards driving off the ammonia
substantially as described.
2. The use of hydrated phosphoric iron ore for the purpose of absorbing ammonia
from sewage effiuent, substantially as described.
Dated this 5th day of November 1895.
T. TWYNAM.
F. E. MATTHEWS.