WO2012118453A1

WO2012118453A1 - Compact system for processing grey wastewater and its reutilization for flushing toilet bowls

Info

Publication number: WO2012118453A1
Application number: PCT/SI2012/000008
Authority: WO
Inventors: Albin Pintar; Janez VRTOVŠEK; Magda COTMAN
Original assignee: Kemijski inštitut
Priority date: 2011-03-01
Filing date: 2012-02-29
Publication date: 2012-09-07
Also published as: SI23669A

Abstract

Based on the embodiment the subject matter invention is introduced, which enables that part of the quantity from the mains network, which is used for flushing the toilet bowl, is replaced by processed grey wastewater. The processing of wastewater is performed in the tank (1), which is by a partitioning wall (1d) separated into an inlet part (1a) and an active part (1b). Inside the bioreactor module (1c), which is immersed inside the active part (1b) of the tank (1) organic substances are removed, while in the ultraviolet disinfection module (2), which is located on the side of the tank (1) the concentration level of active microorganisms is adjusted. The system of electromagnetic valves (4, 5, 6) and the level sensor (3) takes care for the controlled operation of filling and discharging the tank (1) content.

Description

COMPACT SYSTEM FOR PROCESSING GREY WASTEWATER AND ITS REUTILIZATION FOR FLUSHING TOILET BOWLS

Subject of the invention is a compact reactor based system for processing grey wastewater in combination with an intensive biological procedure for the removal of organic substances and procedures of adjusting the microorganism concentration by using UV-light based disinfection. The processed grey wastewater is reutilized for flushing toilet bowls.

Problem solved by the invention

The lack of perfect drinking water represents a problem all over the world, which is potentiated by the population increase and higher urbanization level. At the same time, the majority of households daily consumes large quantities of drinking water even for purposes (e.g. flushing the toilet bowl), where such a water quality is not required. The subject matter invention which enables the reutilization of grey wastewater represents a solution for reducing the quantity of the used tap water in households. Due to its compact implementation the submitted solution is also suitable for smaller residential units.

State of the art

The currently known patented compact (house) system, which enable the reuse of grey wastewater for flushing toilet bowls mostly use non-processed grey wastewater (CN201228372, CN201190305, N201125422), while with patent CN195192092 the specified biological processing of tap water is carried out inside a special filtering unit. The grey wastewater, which results in households and public buildings from taking a shower or bathing, includes soluble organic substances (remains of soap and personal hygiene products), solid particles and microorganisms. Inside the tanks, where the grey wastewater is collected, the microorganisms start to disintegrate organic substances where they keep multiplying out of control, which can result in malodours or even obstruction of the pipes in the basin or toilet bowl. According to the invention this problem has been solved in such a way that the system for processing grey wastewater includes an intensive biological process for the removal of dissolved organic substances and a process for deactivating micro-organisms by UV-light of a certain wavelength. Description of the invention

The invention shall be described based on the embodiment and the figure showing it: Figure 1 : Compact system for grey wastewater processing.

The compact system for processing tap water is shown in Figure 1. It consists of tank 1 , an inlet part 1a of tank 1 , an active part 1 b of tank 1 , a reactor module 1c, a vertical partitioning wall 1d, a disinfection module 2, a level sensor 3, an electromagnetic valve for the discharge of water 4, an electromagnetic valve for the supply of water from the mains network 5, an electromagnetic valve with time controller 6, an open bypass overflow 7 and a discharge 8. With a compact system for grey wastewater processing with the purpose of its reutilization, an intensive biological process for the removal of organic substances existing in wastewater is applied. The biological process is carried out by microorganisms, attached to the carrier material. The system operation is based on the principle of temporary or permanent forced circulation of water through the active part 1b of tank 1 with reactor module and disinfection module 2.

The grey wastewater with a concentration of organic substances expressed as KPK in the range between 10 and 250 mg/l is processed in tank 1 and at the same time serves as a surface- mounted or flush-mounted device. The tank 1 is made in the form of a container with slant bottom featuring an inclination angle of 5 to 20 degrees, and a capacity of 50 to 200 litres, made of plastic material, which is used for classical flushing tanks (toilet tanks). Tank 1 features a vertical partitioning wall 1d, which separates tank 1 into two parts featuring a capacity ratio of 1 :5, while the smaller capacity part represents the inlet part 1a, and the larger capacity part the active part 1 b of tank 1. By the vertical partitioning wall 1d in the upper part of the tank, a direct contact between the water, which stays in the active part b of tank 1 and water which enters tank 1 is prevented. In the lower part of tank 1 the distance between the lower edge of the partitioning wall 1d and the bottom of the tank 1 is between 4 and 10 cm. The water intake (grey wastewater, repumped water and mains water) is implemented in the inlet part 1 a of tank 1 , hence in the part 1d following the partitioning wall with a smaller capacity, while the water is supplied beneath the water level being retained in tank 1. In the lower part of the active part 1a of tank 1 , hence part 1d behind the partitioning wall featuring a larger capacity, a reactor module 1c in the form of a basket is inserted featuring walls from stainless material, which is filled with a microorganism carrier surface. As supporting material a well-defined industrial product with known mechanical and chemical properties is used. The carrier surface is based on expanded polymers in the form of round strips with the commercial name of Mutag BioChip (Umwelttechnologie AB, Germany), which is strongly porous and therefore features a high specific surface of 3,000 m2/m3. The latter provides the possibility that within a smaller volume of the reactor module 1c filled with the carrier surface material, a high concentration of microorganisms is generated, which settle there an are propagating inside the carrier pores. The capacity of the reactor module 1c is ¼ of the capacity of the overall tank 1 , while the reactor module 1c is filled with the carrier up to ½ in such a way that the carrier particles can float inside the specified capacity of the reactor module 1c. The tank 1 is in the upper part equipped with an open bypass overflow 7, which enables the maintenance of the water level inside the tank 1 and discharge 8 through which the tank 1 is ventilated.

On the external wall of tank 1 , a disinfection module 2 featuring a low-pressure UV bulb of 15 - 20 W capacity is located, emitting UV-light in the range between 180 to 20 nm and a pump which provides forced circulation of water between the active part 1 b of tank 1 with the reactor module 1c and the disinfection module 2, while the outflow of water is implemented in the active part 1 b of tank 1 at a height of 1 - 3 cm above the upper edge of the reactor module 1c. When pumping water through the disinfection module 2 the microorganisms, which are dispersed in water are deactivated. Since the active microorganisms are immobilised in the reactor module 1c with the carrier surface, which retains and partially disintegrates also the microorganisms, which enter tank 1 with grey wastewater, this way the water circulation within the system only features a low concentration of dispersed active microorganisms. Therefore, for disinfection purposes a UV-light source with a lower intensity or lower energy consumption can be applied. The flushing of the toilet bowl with the processed water from tank 1 is performed via the electromagnetic valve for the discharge of water 4 linked to the level sensor 3, which enables the selection of a predefined quantity of used water for one flushing. The electromagnetic valve for the discharge of water 4 is located at the inlet part of tank 1 so that the removal of water from tank 1 is performed at the height of 4 cm above the upper edge of the reactor module 1 c. This way the water level inside the tank can only drop up to the height where the reactor module 1c is still submerged in water under any operating conditions. This way the generation of malodours inside the tank 1 along with its dispersion into the environment is prevented. Tank 1 is by way of an external pump upon the event of taking a new shower or bathing filled with grey wastewater, while the excessive water is via the open bypass overflow 7 on top of the inlet part 1a of tank 1 released into the sewage system.

If after the water processing cycle and flushing of the toilet bowl inside tank 1 an insufficient quantity of grey wastewater is available, tank 1 is additionally filled with mains water up to the predefined level via the system of level sensor 3 and the electromagnetic valve for the supply of water from the mains network 5. The quantity of such water is sufficient for a single flushing of the toilet bowl with the maximum defined water quantity. Solid particles, which enter the tank 1 with grey wastewater and dead microorganisms, accumulate in the conical lower part of tank 1. Via the electromagnetic valve with time controller 6, which is located in the conical part at the bottom of the inlet part 1 a of tank 1 , the deposit is in certain time intervals released into the sewage system.

The system for processing grey wastewater and its reutilization, which is subject of the invention is designed in such a way that it enables compact type implementations in the range between 50 and 200 litres, which can be integrated into the sanitary blocks of individual residential units either in flush-mounted or surface-mounted version.

Embodiment

The embodiment is based on the results of the completed tests of biological removal of organic pollution as well as disinfection of the grey wastewater in the pilot system, which is subject of the invention. In previous tests the optimum material type for the microorganism carrier surface has been established as well as the ratio between the capacity of tank 1 and the capacity of the reactor module 1c.

The pilot system consists of tank 1 from transparent polyacrylate with a slant bottom (15 cm x 60 cm x 67/55 cm) and a capacity of 50 I with immersed reactor module 1c and disinfection module 2, equipped with UV-light (low-pressure Hg bulb, 254 nm, 17 W, Helios Italquartz). The system is equipped with two peristaltic pumps, electromagnetic valves 4, 5, 6 (Jaksa) and an ultrasound level sensor 3 (Echoswitch).

The reactor module 1 c represents a basket, enclosed from all sides with a grid from stainless material, which is filled with a microorganism carrier surface (Mutag BioChip). The capacity of the reactor module 1c is ¼ of the capacity of the complete tank 1 , and the capacity of the carrier is ½ of the volume of the reactor module 1c. The properties of the grey wastewater are simulated by the defined addition of personal hygiene agents (liquid soap, shower gel and shampoo) into tap water. The quantity of the organic pollution in the tap water is defined pursuant to data from literature (Eriksson et a/., Characteristics of grey wastewater, Urban Water, 2002). According to this data the average KPK (chemical oxygen requirement) value of grey wastewater is 150 mg/l, while the KPK values in the embodiment are defined by the standardised analytical method (SIST ISO 6060, 1989). The concentration of microorganisms in water is determined by using a standardised method (ISO EN 6222, 1999), which provides results in the form of colony numbers (CFU)/ml.

When monitoring the operation of the pilot system for the processing of grey wastewater the dynamics of generating the grey wastewater in a four-member household has been simulated. Since the synthetically processed grey wastewater does not contain microorganisms, in the initial test phase general household wastewater has been added, so that on the carrier material within the reactor module 1c microorganisms have been able to settle. The important variation of the established KPK values in the waste and processed water has been a sign that the reactor module 1c has become biologically active.

The KPK value and the number of microorganisms after keeping wastewater for a long time (2 day) within the system have been established, while the water has been forcibly circulating between the reactor module 1c and the disinfection module 2. The KPK value has shown 62 mg/l; this value represents the remaining level of organic pollution, which can no longer be biologically disintegrated and the microorganisms can not use it for their growth. The established number of microorganisms in water, which have remained in tank 1 , has been on average 200 - 300 CFU/ml (the threshold value for drinking water is 100 CFU/ml). Measurements have shown that the pilot system has eliminated organic substances up to KPK = 70 mg/l and already one hour after the grey wastewater system has stayed within the system, the concentration of microorganisms at a level of 400 CFU/ml has been maintained. Pilot tests have also shown that within a compact system for processing grey wastewater, which is subject of this invention, water can be prepared featuring such properties that it can be reused for flushing a toilet bowl.

The embodiment, specified in the description serves as an explanation of the invention and not its limitation.

Claims

PATENT CLAIMS

1. The system for processing grey wastewater characterised in that it consists of: a tank (1) with a slant bottom inclined by 5 to 20° C, which holds the reactor module (1 c) including microorganisms, attached to a specific carrier material, where dispersed organic substances are being removed; disinfection module (2), where the microorganisms are deactivated by way of radiation with UV-light; a level sensor (3) and electromagnetic valves (4, 5, 6) which control and perform the filling of the system with grey wastewater or mains water or take care for its discharge from it.

2. The system according to claim 1 characterised in that the overall capacity of tank (1) is in the range between 5 and 200 litres.

3. The system according to claim 1 characterised in that on the conical part of the tank (1) there is a valve with time controller (6) which enables regular release of sediments from the tank (1).

4. The system according to claim 1 characterised in that the tank (1) in the upper part is featuring an open bypass overflow (7) enabling the water level inside the tank (1) to be maintained.

5. The system according to claim 1 characterised in that the tank (1) is equipped with a vertical partitioning wall (1d), which divides the tank into two parts with a capacity ratio of 1 :5, while the smaller capacity refers to the inlet part (1 a) and the larger capacity to the active part (1a) of the tank (1), while the vertical partitioning wall (1d) is located in such a way that in the upper part of the tank it prevents the contact between the water which remains in the active part (1 a) of tank (1) and the water in the inlet part (1 a) of tank (1), while in the lower part of the tank (1) the distance between the tank (1) bottom and the lower edge of the partitioning wall (1d) is between 4 and 10 cm.

6. The system according to any claim 1 - 5 characterised in that in the active part (1 b) of tank (1) a reactor module (1c) is inserted, while the capacity ratio between tank (1) and the reactor module (1 c) is 4: 1.

7. The system according to claim 1 characterised in that the reactor module (1c) is from all sides enclosed by a grid, preferably from stainless material and filled with a microorganism carrier, selected from the group of expanded polymer masses, preferably a material in the form of porous round sheets with the designation Mutag BioChip by Umwelttechnologie AG, where the capacity ratio between the reactor module (1c) and the carrier material is 2: 1.

8. The system according to claim 1 characterised in that inside the disinfection module (2) an UV-light source is integrated, preferably a low-pressure Hg bulb emitting UV-light in the range between 180 - 260 nm, and a power range of 15 -20 W.

9. The system according to claim 1 characterised in that inside the disinfection module (2) there is a pump, which provides forced circulation of water between the active part (1 b) of tank (1) and the disinfection module (2), where the pump takes water from the active part (1 b) of tank (1) in the area being 1 to 3 cm above the upper edge of the reactor module (1c).

10. The system according to claim 1 characterised in that the level sensor (3) and the electromagnetic valve for the supply of water from the mains network (5) ensure that the tank (1) can be filled with the predefined quantity of water from the mains network.

11. The system according to claim 1 characterised in that the supply of grey wastewater, the supply of water from the mains network, repumped between the tank (1) and the disinfection module (2) is performed in the inlet part (1a) of tank (1), while the water flows are supplied at a level from 1 to 3 cm above the upper edge of the reactor module (1c).

12. The system according to claim 1 characterised in that the minimum water level in tank (1) is determined in such a way that the outlet location for water required for flushing a toilet bowl is via the electromagnetic valve for the water outlet (4) set 4 cm above the upper edge of the reactor module (1c).