Note: Descriptions are shown in the official language in which they were submitted.
CA 02467469 2004-05-17
~'~~3 a(~~' T»E ~I~1V;~1~TI~~~
The present invention relates to apparatus for teY~~porar5~ containment of
liquid
waste from relacatable buildings. li~ore particularly, this invention relates
to apparatus
for receiving and temporarily containing sewal;e from skid-mounted temporary
dwelling
units on wellsites and constr~.~ct:ion sites.
l (~ 1r3~1~I~(~~IJI~13 ~~' '~'~~l~ ~l~ilEr~'T~C)hl
Industries such as oil and gas exploration and production, construction, and
mining often require the use of temporary buildings at o r n.ea~ a work site
to house
workers, to serve as temporary offices, or to otherwise support the:
operations of the work
site. It is particularly common to use relocatable buildings for purposes of a
temporary
camp facility, which may include dwelling uYrits, mobile kitchens, wash
facilities, and
recreation facilities. '~lsers of sv~ch relocatable buildings prcyduc.e Liquid
sewage or wastes
of various kinds that require some means of disposal. perhaps the most
e.Q~nmon
requirement is for disposal of h~~man waste and/or wash water, bul: disposal
of otl°Rer Types
Z.(~ of waste, such as industrial waste or laboratory waste:, may be required
i.n. some
ClYCgimStanCes.
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Relocatable buildings fc>r wellsites and construction sites are often provided
in the
form of prefabricated mobile or skid-moun~ed units. lJtanu:acturers of suds
skid-
mounted units included 1~'orthgate Industries Ltd. of Idmon.ton, Alberta, Alta-
Pab
Stnactures Ltd. of Nisku, ~~lberta, and Shanco damp Sn~vices Ltd. of brand
Prairie,
Alberta. Skid-mounted wellsite units, for temporay housing of workers, are
typically 12
feet (36.6 meters) wide, and from 40 to 6~ feet (12.2 to 1~.3 meters) in
length. The units
thus have two short end walls, plus long front and rear walls. Each unit has a
pair of steel
skids, typically IO to 12 inches (%54 to 30j m~~n) high, rurrc~ing the full
length of fhe unit
underneath the floor structure adjacent t:o the :>ide walls. ~hhe floor
structure is typically
of conventional wood-framed construction; e.g., 2xlC~ wood joists with plywood
sheathing. The skids rest on grade, so the ftoor surface iruside the units
will typically be
only 20 to ~.2 inches (54~~ to ~Sg mm) above the adjacent ground :surface.
there dictated by their intended Lgse, such as in dwelling units, kitchens,
and
wash facilities, the skid-mountt~d units will have a plumbing system connected
to one or
more sewage outlets (typically projecting through the rear walls of the Lmits
just below
the floor sheathing), for drainage of sevaage from the units to a sewage
disposal system.
However, construction sites and especially wellsites are often in remote
locations where
there is no sewage collection or treatment system. Theref6re, alternative
means must be
aft provided to dispose of the sewage. The efi:ectiveness <~f such disposal
means is of
particular importance in remote locations preservation of the natural
er~vironme~.t: and
protection of ecological systems are ol' concern.
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A simple type of sewage disposal system that has been used at wellsites and
construction sites consists :in piping the sewage from the temporary buildings
to an open
trench running away from the temporary site. This system's readily apparent
health-
related and environmental concerns male it clearly less than desirable if not
completely
S unacceptable in some situatio~us. A more common temporary sewage system
involves
piping the sewage from the relocatable buildings to a buried or partially
buried central
holding tank. The sewage in central holding tank can there be pw.~nped onto a
septic field
(if environmentally acceptable) or transported (for example by a vacuum trucks
to a
sewage treatment facility. dome sites may have their own sewage°,
treatment system on or
1 ~ near the site, but this will be viable in relatively fever cases, due to
cost considerations.
consideration, on-site this is not practical and complexity, on-site treatment
is less
common.
Regardless of the ultimate disposal method, preaent s:~stems for disposal of
1 S sewage from relocatable buildings can involve a. considerable amount of
planning, layout,
design, excavation, and piping installation. each relocatable building having
a sewage
outlet needs to be connected to a piping system leading to the drainage trench
or holding
tank as the case may be. The zlesign, installation, maintenance, c~nd ultimate
removal of
such systems can involve considerable expense, particularly bwause most if not
all of the
system components will typically be discarded after the system is
decommissioned.
Then the relocatable buildings are being used in l:ree~inl; temperatures;
s~~ch as
dLaring northern Canadian u-inters, the piping system also reeds to be
protected against
CA 02467469 2004-05-17
freezing of the liquid sewage and resultant piping damage and se'vage spills.
'~~'his can be
accomplished by burying the piping, bu.t in practice this is rarely done,
because of cost.
More commonly, the piping system laid on the ground surface, with protection
against
freezing being pro~,rided by Meat-tracing anc~ insulating the piping. In
either case,
however, a significant expense is incu~°red. Furthermore, where tl: a
sewage piping system
is Laid on grade, it can present an obstacle to vehicular and/or pedestrian
traffic, which
may entail the constr~,iction cl' stiles and rarrips far crossing over the
piping ia~ some
locations.
1 C3 In view of the foregoing drawbacks with existing s~jst~°m;~, there
is a need for an
improved sewage collection and disposal system that can be set up to service
re~oc.:atable
buildings on a wellsite, construction site, or other tempor~.ry facility
without need for an
extensive piping network or b~~.ried tanks. There is a furtl~.er need for such
systems that
can be installed and then later removed ~~rith minimal disruption to the
natural
1 ~ environment in the vicinity of the temporary facility. The pr
esc°nt invention is directed to
these needs.
~~~~ s?~l~l~~~ ~~ ~r~ ~~rv~,l~Tr
~Cl In general terms, the present invention is a sewage containment system
that uses
low-profile containment vessels that can be con~cleniently located at ground
level asL~~.cent
to relocatable buildings. The containment v.~ssels are c>f elongate
configuration anal
comparatively shallow depth -- preferably about 16 to 18 irmhes ~~1I0 to 460
m~n~. These
CA 02467469 2004-05-17
conformational characteristics make it possible to rnaximi~:c the vessels'
storage capacity
while being low to the gro~;~~nd to facilitate gravity drainagf~ of sewage
from the
relocatablc buildings. For example, a containment vessel nominally 1 ~ inches
(460
mm) high, 32 inches (~ 1 ~ mm) wide, and 24 feet ('7.3 met>-rs) long has a
gross volL~me of
approximately 96 cubic feet (:2700 liters) or 600 lmperi;al gallons (720 U.S.
gallons).
This vessel mould have a usable storage volume of at least 500 Imperial
gallons (2270
liters, or 600 U.S. gallons).
1~ typical skid-mounted wellsite unit is equipped ~~ith hot and cold water
storage
IO tanks having a total capacity of 350 to 400 Imperial gallons. Therefore, a
single sewage
containment vessel as described above would have more than adequate capacity
to
receive the wellsite unit's full ~-ater storage capacity.
To facilitate connection to the sewage outlet of a relocatable building, the
sewage
containment vessel of the present invention is provided ~~~ith one or more
replaceable
insert members that fit snugly into corresponding access openinga in the roof
member of
the vessel. The insert members preferably will tit into the ;access openings
in liquid-tight
fashion, and even more prefera~sly will melee a vapour-tight: sear. The insert
members are
made of a drillable material (preferably a plastic material), allowing holes
to be drilled in
the field at any convenient location in the insert member so that inlet piping
from the
sewage outlet of one or more buildings can bc~ readily connected to the vessel
without
need for particularly precise pipe fabrication.
5
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Accordingly, in one aspect the present invention is a poz~fable sewage
containment
system, for receiving and temporarily retaining liquid sewage from a
relocatable building
having a sewage outlet, said sewage containment system comprising:
{a) an elongate containment vessel waving a root member and a base member,
and having side walls interconnecting said upper and base members, said
roof member having az~. access opening; and
(b) an insert member adapted to matingly engage said access opening;
wherc,in:
~c) the insert memb<~r is made of a drillable material;
I Q ~d) a plumbing port may be formed in the insert member at a selected
location to recei~~ a a plumbed connection from the sewage outlet of the
relocatable building; arid
(e) the containment vessel further comprises drain connection means, to
facilitate extraction of sev~~age from the containment vessel.
l
In the preferred embodiment, the containment vessel of~ the present invention
has
one or more longitudinal slots running substantially the ull iength of the
vessel, for
receiving elongate insert members which effectively permit c~~nnection of
piping
wherever desired along the length of the vessel. In other emi~odi~rmnts, the
vessel ~zay be
2~ adapted to receive a number of ;Irillable insert members of ;>cluare,
rectangular, polygonal,
curvilinear; or other shapes. 'h'as embodiment has the adva~~tage that where
only ~ax~e or
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two sewage pipes are connected to the vessel, ~h~hen the vessel is :~.ater
moved for use on a
different site, only one or two small insert members will need to be replaced
rather than a
large insert member, thus redLicing cost. however, by having a number of
smaller insert
members, the vessel retains its flexibility in terms of facilil~~ting sewage
pipe connections
at any of numerous locations along the length of the vessel.
In the preferred embodiment, the sewage containment vessel also has a
connection for a vacuum truck or other equipment for rm~novir..g the sewage
from the
vessel. Preferably, the vessel will have one or more camlock fittings to
ensure a vapour-
tight seal to faeilitate vacuurx°k removal of sewage from th.e vessel.
When the buildings
are moved from the site, the containment vessels may be drained and then
conveniently
moved from the site, to be clE°aned as appropriate and installed on a
differerxt site as
desired. The insert members that were drilled to receive sewage piping may be
discarded
and replaced with new insert members for the vessels9 next ~Ese.
l~
In the preferred embodiment, the containment vessel of t:he present invention
is
fitted with fluid level alarm means, whereby faeility operators ma;y be given
warming that
the vessel needs to be emptied. hlso in the preferred embodiment, the vessel
has heating
means, such as a submersible heater, for keeping stored sewage from freezing.
'~: he
iG~ sewage piping from a building being served by the contairirner~t vessel
may be protected
from freezing by means of insulation and/or heat tracing of any well knoum
type.
7
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The containment vessel preferably features one or more lateral connections for
interconnecting one or more additional vessels in fluid communication with
each other.
This arrangement can effectively increase the: sewage storage capacity
available for a
given building, by effectively making available any exec°ss capacity in
an ad~ac;ent or
nearby containment vessel serving another building. The provision of
interconnection
means also affords a cons~eniei,~t way to increase the storage capacity
available to service
a single building or group of closely-spaced buildings by using one or more
interconnected vessels positioned side by side.
1 (1 The containment vessel may also have one or more interior baffles to
enhance the
vessel's structural stiffness. such bafflc,s may be perforated in some fashion
to permit
sewage flow across the bafl~es, thus ensuring uniform distribution of sewage
along the
length of the vessel, and facilitating emptying of the vessel from a single
vacuum
connection at any selected location along the length of the: ve:>sel. The base
menp.ber of
l ~ the vessel may be constructed with a slope to facilitate: flow of sewage
toward. the
vacuum connection. The base member also may be fabricated ~rith a well or
depressed
area to facilitate emptying by p~xmpang or vacuum means.
In the preferred embodiment, the contai:~nent vesse~.. will have two or more
ifting
f~~ Iugs to facilitate transportation to and from sites where the: vessel is
used. In alternative
embodiments, the vessel may be fitted with two or more wheels to further
facilitate
transportation o:~the vessel.
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'hhe containment vessel of the present invention may be made of any material
that
is suitable for liquid-tight fabrication and that is not pr°one to
rapid degradation in
response to extended contact ~~ith moisture and various kinds of' sewage. For
example,
the vessel could be made of welded steel, either stainlesse steel or carbon
steel teat has
been plated or coated to resist or inhibit corrosion. 1:~~ the preferred
eynbodiaa~ent,
however, the vessel is made oi° a plastic material, such as
polypropylene or high-density
polyethylene, that has good corrosion resistance and can be readily formed
into liquid-
tight components using kno~rn fabrication sechniques. '~ he use of such
synthetic
materials has the added advantage of light weight compared to steel, which is
1 G advantageous when the contair:,ment vessel is being shipped by truck or
other means of
transportation.
Ti ~I~ESC h~'I~I~ F' 'I'I3I);~IhfS
1. ~ Embodiments of the invention will now be described with reference to the
accompanying figures, in wlroich numerical references denoi:c life parts, and
in which:
~IIJIZE 1 is a perspective view of the preferred ern~odirr~ent of a sewage
containment vesse:i in accordance with the present invention.
FIGZ1I~~ 2 is a cross-sectional view through the sewage containment
vessel on line A-~ in Figure 1.
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FIG1JRE 2A is a pa~~tial cross-sectional view :>howing an alternative
configuration of the access opening of the sewage containment vessel.
FIGIJI~E 3 is a sc~hetnG.tic elevation view of a sewage co~:~tainment vessel
in accordance with the present invention positioned adjacent to the rear
wall of a skid-mounted wellsite unit.
DEZ'r~II~ED DESCItIF'~'I~lo1 ~F 'I'HE FREFEIH~ED F;MB~DIMEI~fI'
As illustrated in Figure's 1 and 2, the present invention is an elongate
sev~rage
containment vessel 10 having a roof member 12 and a base member 14
interconnected by
side walls 16 and end walls 1. The roof member ~2 has a~:Y access opening 19
adapted to
receive an insert member 20 which through which a plumbing port 22 may be
formed in
a user-selected location, by u:rilling or other suitable rr~eans, to receive a
plumbed
r~ connection 3~ for connecting to a sewage outlet. of a relocat:able
building.
In the preferred embodiment, the access opening 19 is ao elonga.te slot
running
substantially the full length of the containment vessel 1~, .as shown in
Figure l, with an
insert member 20 or corresponding length. This arrangement allows for plumbing
ports
22 to be placed a virtually aa~~~ point along tlae length of ~:he vessel 10.
As showv~ i.n
particular detail in Figure 2, the access opening 19 may have L-shaped ledgers
15 along
each longitudinal edge of the access opening 19, for supporting the insert
member.
Depending on the dimensions selected ~'or the ledgers 15, the top surface of~
the insert
1 f)
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member 20 can be flush with the roof member 12 of the containment vessel 10,
or it
could be slightly above or below the roof m;.mber 12. In the alternative
embodiment
shown in Figure 2A, an upstanding curb 17 is provided ad~ac;ent to the edges
of the access
opening 19 for supporting the insert member 20. Persons skilled in the art of
the
invention will appreciate that the means for supporting the insert: member 10
in
association with the access opening 19 other than as show~~ in Figures 2 and
ZA may be
devised and used without departing from the concept of the invention.
In an alternative embodiment (not illustrated}, the containment vessel 10 may
have a series of elongate access openings 19 extending substantially the full
length of the
roof member 12, for receiving a corresponding number of correspondingly
shorter insert
members 20. This alternative configuration has the advantage of providing the
roof
member 12 with greater structural strength and stiffness, as compared to the
embodiment
vrhere the access opening 19 and the insert member 20 extend substantially the
full Ien.gth
of the containment vessel ll~. A further potential benefit o f this
alternaf~ive configuration
is that it provides for the possibility that one or rr°~ore of the
multiple elongate insert
members 10 rr~ay not need to have a plumbing port 22 for a given installation,
so such
unperforated insert members 10 can contimae to be used when the containment
vessel 1.0
is re-used at a new location.
zo
In other unillustrated embodiments, the roof merrlber 12 may have a number of'
small access openings 19, which could be of square, circular, polygonal, or
other selected
shape and would be adapted to receive insert rr~c;mbers 10 or~ corresponding
shape. ~"hese
11
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alternative configurations would have benerits similar to those previously
described in
connection with the use of multiple elongate insert members 10. The use of
circular
insert members 10 may be particulat°ly advantageous in tlr,at it would
be impossible for
the insert members 10 to fall through their corresponding access openings lg.
The same
advantage may also be available usin~,r insert members 10 of other shapes as
well,
depending on the relative dimensions of the insert members 10 and their
corresponding
access openings 19.
The containment vessel 10 is fitted witl°~ drain connection means.,
whereby sewage
l~ may be extracted from the interior of the vessel 1~ for disposal at a
suitable facility. The
drain connection means may comprise a pipe extending through the roof member
of the
vessel 10 to a selected point above the base member of tl~° vessel 10.
In the preferred
embodiment, the drain connection m~;ans Till be a vacuum connectioru, as
conceptually
indicated by reference numeral 3~ in p'igure 2. The containment vessel :~0
preferably will
1 ~ be fitted with a vent (not shown to prevent or relieve: undesirable
accumulation of
~rapours inside the vessel 1~.
In the preferred embodiment, the containment vessel 10 will also have fl~~id
level.
alarm means (not shown), wl~ch may be set to alert a user that sewage inside
tlve vessel
2(1 1has reached or is approaching a level necessitating that the vessel 10 be
drained.
Also in the preferred embodiment, the containment vessel 10 'will have at
least
ane fitting for receiving a submersible electric heater, with a heating
element that will be
12
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at least partially immersed in any liqLnd sewage present anside the vessel 10
so as to
prevent freezing of the sewage.
Figure ~ depicts a typical instal:~ation of a, containment vessel 10 in
association
with a skid-mounted wellsite unit 100 or other relocatable building. Figure 3
conceptually
depicts the floor structure 1~0, roo l' strL:cture 130, and rear wall 140 oj'
the wellsite unit
100. 'I'he wellsite unit 100 is supported by longitudinal steel skids 110
which rest directly
on grade (indicated by hatching. ~, containment vessel 10 in accordance with
the present
invention is positioned on grade adjacent to and substantially parallel to the
rear wall 1~0
1~ of the wellsite unit 100. ~ plumbing port ~2 is drilled or otherwise
for°med in the insert
member 20 disposed in the access opening lad of' the co~~aainment ve:~sel,
arid suitable
piping 40 is connected at one er~d to the sewage outlet 1.~0 of the wellsite
unit and is
fitted at the other end into the plLimbing port 2~ in the inse~ ~ member 20
such that sewage
will flow from the wellsite unit 100 into the containment vessel 10.
l~
It will be readily appreciate by those spilled in the art that var:~c~us
modificatio~.~s
of the present invention may be devised withocat departing from the essential
concept of
the invention, ar~d all such modifications are intended to he included in the
scope of the
claims appended hereto.
In this patent document, the word °°comprising°°
is used in its non-limiting sense to
mean that items following that word are included, but ite~~:s not specifically
mentioned
are not excluded. fi reference to an element by the indefinite article
°'a°' does not exclude
13
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the possibility that ~xiore than sine o~ the element is prese-rit, unless the
context clearly
req~.~ires that there be one and o~~ly one s7ach element.
I4
