GB2393716A - A domestic sewage treatment system - Google Patents

A domestic sewage treatment system Download PDF

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Publication number
GB2393716A
GB2393716A GB0321281A GB0321281A GB2393716A GB 2393716 A GB2393716 A GB 2393716A GB 0321281 A GB0321281 A GB 0321281A GB 0321281 A GB0321281 A GB 0321281A GB 2393716 A GB2393716 A GB 2393716A
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GB
United Kingdom
Prior art keywords
holding tank
discharge
liquor
period
sewage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB0321281A
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GB0321281D0 (en
GB2393716B (en
Inventor
James Constantine Fay
David Fay
Graham Fay
Original Assignee
James Constantine Fay
David Fay
Graham Fay
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to IE20020730 priority Critical
Application filed by James Constantine Fay, David Fay, Graham Fay filed Critical James Constantine Fay
Publication of GB0321281D0 publication Critical patent/GB0321281D0/en
Publication of GB2393716A publication Critical patent/GB2393716A/en
Application granted granted Critical
Publication of GB2393716B publication Critical patent/GB2393716B/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00Biological treatment of water, waste water, or sewage
    • C02F3/02Aerobic processes
    • C02F3/12Activated sludge processes
    • C02F3/20Activated sludge processes using diffusers
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00Biological treatment of water, waste water, or sewage
    • C02F3/006Regulation methods for biological treatment
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00Controlling or monitoring parameters in water treatment
    • C02F2209/42Liquid level
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00Controlling or monitoring parameters in water treatment
    • C02F2209/44Time
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02WCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00Technologies for wastewater treatment
    • Y02W10/10Biological treatment of water, waste water, or sewage

Abstract

A biological sewage treatment system 1 including a sewage holding tank 2 with an inlet 3 and an outlet and a diffuser 7 mounted in the holding tank 2. A treated liquor discharge pump 6, is also included with an inlet 24 communicating with an interior of the holding tank and an outlet 25 which is connected to a liquid discharge line 5 for the discharge of treated liquor from the holding tank 2. A three way valve (not shown) may be used in the discharge line 5 to further re-circulate the liquor. The method of use can include an initial settling period before aeration, followed by a further settling period. An irrigation system for the treated waste water may be provided.

Description

GB 2393716 A continuation (72) Inventor(s): James Constantine Fay David

Fay Graham Fay (74) Agent and/or Address for Service: Urquhart-Dykes & Lord Alexandra House, 1 Alexandra Road, SWANSEA, SA1 BED, United Kingdom

1 239371 6

- 1 "A Dom - tic Sewage Treatment System" This invention relates to a domestic sewage treatment system and process.

5 Where domestic sewage systems cannot be connected to a main sewer some other method of handling the sewage waste must be provided. One typical system involves the use of a septic tank through which sewage flows. Such septic tanks generally have two or more chambers in which the waste is allowed to settle before discharging purified liquor into an imgation system or the like buried in a field. On a regular basis

10 sludge which collects in the septic tank must be pumped out for safe disposal elsewhere. This is relatively expensive and somewhat inconvenient. Also this sludge is a nuisance as it has a very unpleasant odour caused by hydrogen sulphide gas (rotten egg smell).

15 The present invention is directed towards overcoming these problems.

According to the invention there is provWed a domestic biological sewage treatment system including a sewage holding tank having an inlet for reception of raw sewage and an outlet for discharge of treated liquor, a diffuser mounted in the holding tank, 2 0 said diffuser having an inlet connected to an air supply means, said diffuser having a plurality of outlet openings for discharging air into the holding tank a treated Ib, uor discharge pump having an inlet communicating with an interior of the holding tank and an outlet which is connected to a liquid discharge line for discharge of treated liquor from the holding tank.

In one embodiment of the invention a Whey discharge valve is mounted in the liquid discharge Une, said Away valve having an inlet, a first outlet and a second outlet, said valve inlet being connected to the discharge pump outlet, said valve first outlet being connected to a recirculating line having an outlet which discharges into the holding 3 0 tank, and said valve second outlet being connected to a discharge pipe for discharge of treated liquor from the homing tank, saw valve being operable such that when the first outlet is open the second outlet is closed and when the first outlet is closed the second outlet is open.

1' - 2 In a further embodiment means is provided for controlling delivery of air from the air supply means to the diffuser. Preferably said means is operable to continuously supply air to the diffuser during an aerating period.

5 Conveniently the air supply means is a blower mounted on the holding tank.

In another embodiment the discharge pump is a submersible pump mounted within the holding tank.

10 In another embodiment a pump cut-out switch is provided associated with the discharge pump, said cut-out switch operable to switch off the pump when the liquid level in the holding tank falls to a predetemnined level.

In another embodiment the liquid discharge line is connected to an irrigation system 15 outside the holding tank for disposal of treated liquid.

In a further embodiment control means is provided for regulating operation of the air supply to the diffuser, for regulating operation of the discharge pump and for regulating operation of the discharge valve. Said control means may conveniently be provided by 2 0 a pre-programrned PLC.

It is desirable that the controller, the blower and electrical controls for the blower and the discharge pump are housed in a weatherproof kiosk which is mounted on top of the holding tank.

In another aspect the invention provides a domestic biological sewage treatment process, including: delivering sewage waste to a sewage holding tank forming a reservoir of 3 0 sewage liquor, aerating the sewage liquor in the holding tank for a preset aerating period, after aerating allowing the aerated sewage liquor to settle in the holding tank

- 3 for a preset settling period, and discharging a quantity of treated liquid from the holding tank.

5 In another embodiment the process includes aerating the waste continuously during the aerating period.

In a preferred embodiment the aerating period is between 8 hours and 16 hours, and most preferably is about 12 hours.

In another embodiment the process includes aerating the sewage liquor by finely diffusing air into the sewage liquor during the aerating period.

In a further embodiment the sewage liquor is aerated by generating a pressurised air 15 supply and discharging said air supply through a diffuser located at a bottom of the homing tank during the aerating period.

In another embodiment the process includes discharging treated liquid from the homing tank by initially recirculating treated liquor through a discharge line and back to 2 0 the holding tank and subsequently discharging treated liquor through the discharge line for disposal outside the holding tank.

In another embodiment the process includes disposing of the treated liquor by delivering the treated liquor through an associated imgation system connected to the 2 5 discharge line outside the holding tank.

In another embodiment the settling period for the aerated sewage liquor is between 6 hours and 10 hours, and most preferably the settling period is about 8 hours.

30 In a further embodiment the process includes settling the liquid for an initial primary settling period, recirculating a quantity of treated liquor through the discharge pump and back to the homing tank during a brief recirculating period, and

- 4 thereafter settling the sewage liquor in the holding tank for a secondary settling period before discharging treated liquor from the homing tank.

5 In another embodiment each of the pan ary settling period and the secondary settling j period is at least 1 hour, and preferably at least 2 hours duration. Ideally, the primary settling period is about 6 hours and the secondary settling period is about two hours duration. 10 The recirculating period should be sufficient to flush through the discharge pump and the discharge line upstream of a discharge valve which controls discharge of treated liquor from the holding tank. Typically the recirculating period is less than 1 minute and preferably is of the order of 20 to 30 seconds.

15 The invention will be more clearly understood by the following description of some

embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which; Fig. 1 is a sectional elevational view of a domestic sewage treatment system 2 0 according to the invention; Fig. 2 is a plan view of the sewage treatment system; and Fig. 3 is a detail sectional elevational view taken along the line al - lit of Fig. 1 2 5 showing portion of the sewage treatment system; Fig. 4 is a sectional elevational view of a sewage treatment system of the invention retrofrited to an existing septic tank; 3 0 Fig. 5 is a plan view of the system shown in Fig. 4; Fig. 6 is a plan view of the septic tank; and Fig. 7 is a sectional elevational view of the septic tank.

- 5 Referring to the drawings, and initially to Figs. 1 to 3 thereof, there is illustrated a domestic biological sewage treatment system according to the invention indicated generally by the reference numeral 1. The system 1 comprises a sewage holding tank 5 2 having an inlet 3 for reception of raw sewage delivered through a raw sewage inlet pipe 4 which is connected to a domestic dwelling. A holding tank outlet for discharge of treated liquor comprises a discharge line 5 which delivers treated liquor to an irrigation system located downstream of Uhe holding tank 1. A treated liquor discharge pump 6 is located Within the holding tank 2 to discharge treated liquor from the holding 10 tank 2 through the discharge line 5. A amuser assembly indicated generally by the reference numeral 7 is mounted at a bottom of Uhe holding tank 2 for aerating liquid within the holding tank 2.

The holding tank 2 has a base 10 with an upstanding side wall 11 and a top 12. The 15 top 12 has an access opening 13 closed by a cover 14. A through hole 16 is provided in the top 12 for through passage of pipework, cabling and Uhe like. A weatherproof control kiosk 17 is mounted directly above Uhe opening 16.

The discharge pump 6 is suspended centrally within an upper portion of the holding 2 0 tank 2 by means of a chain 20 and hanger 21 attached to an inside face of the top 12 of the holding tank 2. A power supply cable 22 for the pump 6 passes up through the hole 16 to the control kiosk 17 within which is housed electrical contactors for connection to a power supply and a controller for operation of the discharge pump 6.

The discharge pump 6 has an inlet 24 and an outlet connected to a discharge pipe 25.

25 This discharge pipe 25 feeds up through the hole 16 to a 3-way valve (not shown) housed within the control kiosk 17. An outlet end of the discharge pipe 25 connects to an inlet of the 3-way valve. This 3-way valve has a first outlet which is connected to a recirculation line 26 which feeds back down through the hole 16 for discharge adjacent the base 10 of the tank 2. A second outlet of the 3-way valve is connected to the 3 0 discharge line 5 for discharging treated liquor to the irrigation system externally of the holding tank 2. This 3 way valve is electrically operated for switching between the recirculation line 26 and the discharge line 5 as will be described in more detail later.

The controls for the 3-way discharge valve are also housed within the control kiosk 17.

l - 6 - The diffuser assembly 7 is mounted centrally on the base 10 of the holding tank 2.

The diffuser assembly 7 connects by means of an air line 30 with an electrically operated blower (not shown) which is mounted in the control Wosk 17 together with controls for the blower. The blower delivers air through the air line 30 and through 5 anus 31 of the diffuser assembly 7 which have outlet openings to diffuse the air as fine bubbles into an interior of the holding tank 2 for aeration of liquid retained within the holding tank 2 in use.

The holding tank 2 is mounted below ground adjacent a domestic dwelling with the 10 control kiosk 17 projecting upwardly from ground level 18 as shown in Fig. 1. The sewage inlet 3 of the holding tank 2 is connected to a raw sewage pipe 4 coming from the domestic dwelling for delivery of domestic sewage into the holding tank 2. During the day, typically between 8am and 8pm the blower is operated continuously for continuous aeration of sewage liquor within the holding tank 2. Fine bubbles of air are 15 diffused up through the sewage liquor within the holding tank 2 for biological treatment of the sewage by aerobic bacteria present within the holding tank 2. The aerobic bacteria digests the sewage, reducing the biochemical oxygen demand (BOO) by converting the organic content of the sewage to a chemically and organically inert sludge. The oxygen input delivered in the air through the diffuser assembly 7 is 2 0 calculated to supply sufficient oxygen to support the bacteria colony in the activated sludge within the holding tank 2 in addition to creating nitrifying bacteria and to provide for simultaneous sludge stabilization.

After the desired aeration period has been completed, that is at 8pm, a controller in the 2 5 control kiosk 17 switches off the blower and the sewage liquor within the holding tank 2 is allowed to settle for a primary settling period. In the early morning hours when little or no sewage inflow occurs, that is at about 2am the discharge pump 6 is switched on for a brief recirculation period of about 20 to 30 seconds. The Away discharge valve is switched to the recirculation position so that treated liquor is discharged by the pump 6 30 back through the recirculation line 26. This flushes through the pump 6 and discharge pipe 25 to clear the pump 6 and discharge pipe 25 of any mixed liquor that might have entered during the aeration period.

Settlement of the sewage liquor within the holding tank 2 then continues for a

secondary settlement period until about 4am and then the discharge valve is switched to the discharge line 5 and the discharge pump 6 is operated to discharge treate liquor from the holding tank 2 through the discharge line 5 to the irrigation system for disposal of the treated liquor. The discharge pump 6 is automatically stopped by a 5 float switch associated with the pump 6 when the sewage liquorwithin the holding tank 2 falls to a predetermined level. The position of the float switch is arranged to avoid discharge of any floating material from the holding tank 2. The discharge pump is srzed such that H will discharge the previous days inflow sewage volume in up to 3 hours. Automatic control of the air blower for the diffuser assembly 7, the 3-way discharge valve and the discharge pump 6 is by way of a pre-programmed PLC. Electrical controls for the blower, the pump 6 and the 3-way discharge valve such as miniature circuit breakers and the PLC together with the blower and the 3- way discharge valve 15 are all housed in the weatherproof control kiosk 17.

It will be appreciated that the invention provides a compact and efficient prefabricated domestic biological sewage treatment system for the efficient handling and disposal of domestic sewage waste. Any sludge produced is aerobic and odourless. The sewage 2 0 is simply treated in a single tank.

Conveniently the sewage treatment system of the invention may be retrofitted to suitable existing septic tanks obviating costly and disruptive excavations and construction work in mature gardens for example.

Referring to Figs. 4 to 7 there is shown a sewage treatment system of the invention retrofitted to an existing septic tank. The sewage treatment system is indicated generally by the reference numeral 40. Parts similar to those described previously are assigned the same reference numerals. In this case the system is fated to an existing 30 septic tank 42 which forms the sewage holding tank. This conveniently avoids the need to dig up a garden or the like to install a new tank.

The invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail within the scope of the appended claims.

Claims (29)

( - 8 - CLAIMS
1. A domestic biological sewage treatment system including a sewage holding tank having an inlet for reception of raw sewage and an outlet for discharge of 5 treated liquor, a diffuser mounted in the holding tank, said diffuser having an inlet connected to an air supply means, said diffuser having a plurality of outlet openings for discharging air into the hokding tank, a treated liquor discharge pump having an inlet corrrnunicating with an interior of the holding tank and an outlet which is connected to a liquid discharge line for discharge of treated 10 liquor from the holding tank.
2. A system as claimed in claim 1 wherein a 3-way discharge valve is mounted in the liquid discharge line, said Away valve having an inlet, a first outlet and a second outlet, said valve inlet being connected to the discharge pump outlet, 15 said valve first outlet being connected to a recirculating line having an outlet which discharges into the holding tank, and said valve second outlet being connected to a discharge pipe for discharge of treated liquor from the holding tank, said valve being operable such that when the first outlet is open the second outlet is closed and when the brat outlet is closed the second outlet is 2 0 open.
3. A system as claimed in claim 1 or 2 wherein means is provided for controlling delivery of air from the air supply means to the diffuser.
2 5
4. A system as claimed in claim 3 wherein said means is operable to continuously supply air to the diffuser during an aerating period.
5. A system as claimed in any preceding claim wherein the air supply means is a bkver mounted on the holding tank.
6. A system as claimed in any preceding claim wherein the discharge pump is a submersible pump mounted within the homing tank.
7. A system as claimed in any preceding claim wherein a pump cut-out switch is
- 9 provided associated with the discharge pump, said cut-out switch operable to switch off the pump when the liquid level in the holding tank falls to a predetermined level.
5
8. A system as claimed in any preceding claim wherein the liquid discharge line is connected to an irrigation system outside the holding tank for disposal of treated liquid.
9. A system as claimed in any preceding claim wherein control means is provided 10 for regulating operation of the air supply to the diffuser, for regulating operation of the discharge pump and for regulating operation of the discharge valve.
10. A system as claimed in claim 9 wherein said control means is provided by a preprogrammed PLC.
11. A system as claimed in any preceding claim wherein the controller, the blower and electrical controls for the blower and the discharge pump are housed in a weatherproof kiosk which is mounted on top of the holding tank.
2 0
12. A domestic biological sewage treatment process, including: delivering raw sewage waste to a sewage holding tank fomming a reservoir of sewage liquor, 25 aerating the sewage liquor in the holding tank for a preset aerating period, after aerating allowing the aerated sewage liquor to settle in the hokding tank for a preset settling period, and À 30 discharging a quantity of treated liquid from the holding tank.
13. A process as claimed in cdaim 12 which includes aerating the waste continuously during the aerating period.
14. A process as claimed in claim 12 or 13 wherein the aerating period is between 8 hours and 16 hours.
5
15. A process as claimed in claim 14 wherein the aerating period is about 12 hours.
16. A process as claimed in any preceding claim which includes aerating the sewage liquor by finely diffusing air into the sewage liquor during the aerating 1 0 period.
17. A process as claimed in any of claims 12 to 16 wherein the sewage liquor is aerated by generating a pressurised air supply and discharging said air supply through a diffuser located at a bottom of the holding tank during the aerating 1 5 period.
18. A process as claimed in any of claims 12 to 17 which includes discharging treated liquid from the homing tank by initially recirculating treated liquor through a discharge line and back to the holding tank and subsequently 2 0 discharging treated liquor through the discharge line for disposal outside the homing tank.
19. A process as claimed in any of claims 12 to 18 which includes disposing of the treated liquor by delivering the treated liquor through an associated irrigation 2 5 system connected to the discharge line outside the holding tank.
20. A process as claimed in any of claims 12 to 19 wherein the settling period for the aerated sewage liquor is between 6 hours and 10 hours.
3 0
21. A process as claimed in claim 20 wherein the settling period is about 8 hours.
22. A process as claimed in any of claims 12 to 21 wherein the process includes settling the squid for an initial primary settling period,
- 11 -
recirculating a quantity of treated liquor through the discharge pump and back to the holding tank during a brief recirculating period, and
23. A process as claimed in claim 22 wherein each of the primary setting period and the secondary settling period is at least 1 hour.
10
24. A process as claimed in claim 23 wherein the primary settling period is about 6 hours and the secondary settling period is about two hours duration.
thereafter settling the sewage liquor in the homing tank for a secondary 5 settling period before discharging treated liquor from the holding tank.
25. A process as claimed in any of cairns 22 to 24 wherein the recirculating period is sufficient to flush through the discharge pump and the discharge line 15 upstream of a discharge vain/e which controls discharge of treated liquor from the holding tank.
26. A process as claimed in claim 25 wherein the recirculating period is less than 1 minute.
27. A process as claimed in claim 26 wherein the recirculating period is of the order of 20 to 30 seconds.
28. A domestic biological sewage treatment process substantially as hereinbefore 2 5 described with reference to the accompanying drawings.
29. A domestic biological sewage treatment system substantially as hereinbefore described with reference to the accompanying drawings.
GB0321281A 2002-09-10 2003-09-10 A domestic sewage treatment system Expired - Fee Related GB2393716B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
IE20020730 2002-09-10

Publications (3)

Publication Number Publication Date
GB0321281D0 GB0321281D0 (en) 2003-10-08
GB2393716A true GB2393716A (en) 2004-04-07
GB2393716B GB2393716B (en) 2006-03-15

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Family Applications (1)

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GB0321281A Expired - Fee Related GB2393716B (en) 2002-09-10 2003-09-10 A domestic sewage treatment system

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IE (2) IES20030654A2 (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3737382A (en) * 1971-09-27 1973-06-05 R Fletcher Refrigerated surge tank for use with aerobic sewage digestion system
US4828563A (en) * 1985-06-18 1989-05-09 Dr. Muller-Lierheim Ag Implant
US5587081A (en) * 1994-04-26 1996-12-24 Jet-Tech, Inc. Thermophilic aerobic waste treatment process
WO1999037588A1 (en) * 1998-01-27 1999-07-29 Sea Sanitizer International, L.L.C. On board treatment system
US6004463A (en) * 1997-03-10 1999-12-21 Swett; Thomas R. Waste water treatment system and method

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1234567A (en) * 1967-06-22 1971-06-03
DE4235540A1 (en) * 1991-10-21 1993-03-04 Christian Weise Simple and domestic sewage clarification system - contains clarification and oxidn. shafts in single tank and feed and discharge pipes

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3737382A (en) * 1971-09-27 1973-06-05 R Fletcher Refrigerated surge tank for use with aerobic sewage digestion system
US4828563A (en) * 1985-06-18 1989-05-09 Dr. Muller-Lierheim Ag Implant
US5587081A (en) * 1994-04-26 1996-12-24 Jet-Tech, Inc. Thermophilic aerobic waste treatment process
US6004463A (en) * 1997-03-10 1999-12-21 Swett; Thomas R. Waste water treatment system and method
WO1999037588A1 (en) * 1998-01-27 1999-07-29 Sea Sanitizer International, L.L.C. On board treatment system

Also Published As

Publication number Publication date
IES20030654A2 (en) 2004-03-10
GB0321281D0 (en) 2003-10-08
IE20030653A1 (en) 2004-03-10
GB2393716B (en) 2006-03-15

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 20070910