Method and device for treating graywater in order to produce service water

Abstract

The invention relates to a method and a device for treating greywater in order to produce service water, having a cleaning process with a coarse filtering process of the greywater, a preferably aerobic biological purification process with a sedimentation of particles and suspended matter, and a subsequent ultrafiltration process, preferably using a membrane filter, wherein the purification process is controlled at least with respect to the biological purification process, and the ultrafiltration process is controlled on the basis of the pollution of the greywater.

Description

[0001] METHOD AND DEVICE FOR TREATMENT OF GREYWATER INTO PROCESS WATER

[0002] The invention relates to a method for treating grey water into process water.

[0003] Using or reusing domestic greywater (wastewater from bathrooms / showers / washing machines / kitchens) for flushing toilets, watering gardens, cleaning purposes, and much more is a way to conserve drinking water reserves. The relevant regulations and DIN / EN standards describe the requirements for treated greywater (=process water) as follows:

[0004] It must be hygienically impeccable;

[0005] The water must be clear, free of odor and free of other residues.

[0006] The water must be storable, as it must be stored in cisterns, for example, for up to four weeks.

[0007] This water is also referred to as care water in Germany and could also be used for showering and bathing in the future if the law allows it.

[0008] State-of-the-art greywater treatment includes various processes, from chlorination and UV treatment to membrane filtration. The results of state-of-the-art greywater treatment are inadequate because different influencing factors / parameters interact with each other.

[0009] Regarding the state of the art, reference is made to DE 10 2008 049 970 A1 as an example. The process described therein requires improvement with regard to process water quality. It should be noted at this point that with increasing water scarcity, it will be necessary to purify at least slightly contaminated water for further use. For a more comprehensive discussion of the underlying situation, conceptual definitions are important.

[0010] Process water is defined as water that can be used for commercial, industrial, agricultural, or similar purposes with various quality characteristics. The basis for this is DIN 4046.

[0011] Greywater is wastewater that originates from showers, bathtubs, hand basins, kitchens, and even washing machines. It should be noted that water from toilets and other drains is not considered greywater.

[0012] Rainwater refers to natural precipitation, i.e., rain, snow, dew, and fog. Rainwater is not contaminated by use.

[0013] The present invention is based on the object of treating grey water and / or rain water into process water of sufficiently good quality, instead of disposing of the grey water in the wastewater.

[0014] The effort to treat greywater and / or rainwater into domestic water is based on the consideration that, on average, every German citizen consumes approximately 120 liters of drinking water per day. The majority of this is used for personal hygiene. The resulting wastewater, known as "greywater," can account for approximately 50% of all domestic wastewater. It typically flows unused into the sewer system. Especially in times of climate change and its consequences, including heat waves and droughts, this represents a tremendous waste of precious resources.

[0015] With sensible and effective greywater treatment, the environment is helped and costs are reduced. Collected and treated greywater can be used for flushing toilets, washing machines, or watering the garden. Drinking water consumption can be significantly reduced by using greywater. This translates into lower costs for drinking water and wastewater.

[0016] Therefore, an effective method and a corresponding device for the treatment of grey water into process water should be specified, according to which a sufficiently good grey water treatment and a reliable provision of process water for the aforementioned purposes can be achieved using simple means.

[0017] The above object is achieved by the inventive method according to claim 1. The inventive method comprises a coarse filtration of the greywater, a preferably aerobic biological treatment with sedimentation of particles and suspended matter, and a subsequent ultrafiltration, preferably using a membrane filter. It is essential to the invention that the treatment process, at least with regard to the biological treatment and the ultrafiltration, is regulated depending on the greywater contamination.

[0018] In light of the invention, the greywater to be treated is freed of coarse contaminants, such as hair. This occurs in a coarse filter. The coarsely filtered greywater then undergoes a preliminary clarification, in which sediments such as dust and sand settle. A biological preliminary clarification takes place. This preliminary clarification takes place before the actual ultrafiltration. Ultrafiltration is a special type of membrane filtration.

[0019] With regard to membrane filtration, the service life of the membrane and the quality of the membrane filtration are particularly important. According to the required control system, the membrane filter is fed with the existing greywater in a controlled manner, particularly taking into account the gentle operation of the membrane filter. After ultrafiltration, clean process water is obtained.

[0020] With regard to the greywater system according to the invention, the above object is achieved by the features of the independent claim 16. The greywater system according to the invention comprises, in accordance with the above statements regarding the method according to the invention, a control system for the purification process, at least with regard to biological purification and ultrafiltration, depending on the greywater contamination. The grade or composition of the greywater, and thus its quality, is determined in the primary clarifier and greywater tanks, especially since the water is pumped from one tank to the other and aerated in the respective tanks. The pumping and aeration rates, as well as the residence time in the respective tanks, are continuously adapted to the process in order to ensure the most gentle treatment of the greywater for the downstream filter.On the one hand, it is important to protect the membrane filter and, on the other hand, to ensure that the treated greywater is of sufficiently good quality, namely that it is sufficiently clean for the process water.

[0021] The filter(s) are preferably fed by a self-priming pump, which can be frequency-controlled. The control loop is determined by the pressure in the filter and the flow rate.

[0022] In addition, the filters are periodically backwashed to ensure excellent filtration performance throughout the process. The backwash water is returned to the greywater tank, so this water is also available for treatment. This ensures no water is lost. The control system also applies here.

[0023] It should be noted here that the process according to the invention does not use harmful chemicals that could impact or even harm the environment. Instead, biological degradation takes place. Returned contaminant particles are removed as solids. Furthermore, the entire process is optimized in terms of energy and cost-effectiveness through control, with the primary goal being the production of sufficiently pure process water. With regard to the control system, it is particularly worth mentioning that the process parameters are continuously measured and, if necessary, recorded. This can be done on a central server via the cloud. Unauthorized access to the recorded data is effectively prevented by standard security measures.

[0024] The process according to the invention utilizes sophisticated control and regulation technology that allows each individual section of the greywater treatment process to be controlled and monitored. The treatment system follows any changes in the greywater inflow and continuously adapts to the respective greywater quality. The plant operator can access and influence the process online.

[0025] For control and / or regulation, a variety of sensors are installed in the system to obtain information about the respective water composition or quality. This way, a wide variety of values ​​can be measured in both the greywater and the recycled greywater (i.e., the process water) and used to control / regulate the process, namely oxygen, turbidity, total organic carbon, temperatures (including ambient temperatures), spectral absorption coefficient, COLORa, filtrate quantity, etc. The required sensors are preferably installed in a bundle, if possible in combination with one another, at the lowest point in the respective tank. The measured values ​​​​obtained by the sensors are preferably used for control and regulation using KL applications, i.e., using KL-specific algorithms.

[0026] The method and device according to the invention can be followed by a more extensive water treatment system, which, as described above, is also equipped with sensors. Afterward, the process water can be used, for example, with bacteria, as so-called maintenance water for showering and bathing. The aforementioned sensor technology can also be applied to process water.

[0027] It is also conceivable to use the greywater and process water for heat recovery, which could take place, for example, before or in the greywater collection tank or before or in the process water collection tank. Ultimately, heat recovery is conceivable before or in all collection tanks, depending on the specific system design.

[0028] The heat is extracted regularly via heat exchangers and, if necessary, via a heat pump in order to achieve the best possible use of available heat.

[0029] The heat generated in this way can, for example, be fed into the drinking water system, although this requires a decoupled piping system for hygiene reasons. This requirement is a result of legal regulations.

[0030] It is also conceivable to monitor the membrane filter(s) for contamination and / or wear by checking the flow rate and / or water quality after filtration. This allows filter life to be predicted and the need for filter replacement to be indicated.

[0031] It is also conceivable to use the method and device according to the invention for the selective filtration of rainwater. This eliminates the need for biological processing steps. Due to the aeration and filtration through the membrane (ultrafiltration), even heavily contaminated rainwater can be treated to produce process water that complies with standards. This is possible independently of the greywater treatment.

[0032] A particularly advantageous option, and one that improves the efficiency of the entire system, is alternating operation between the treatment of greywater and rainwater, whereby the alternating operation of the membrane system is crucial. Such an expansion of the system requires a separate tank as a rainwater buffer. It is particularly advantageous if the system switches automatically or on demand to the corresponding source – greywater buffer or rainwater buffer. It is essential that the greywater (process water) treated according to the above specifications not only complies with the bathing water guidelines, but also falls below the limit values ​​specified therein, and that this does so without additional aids such as UV disinfection or the like. In the future, it is conceivable that the appropriately treated water will be used as so-called maintenance water for showering and bathing.A corresponding change in the law that will allow this use is pending.

[0033] There are now various possibilities for advantageously embodying and developing the teaching of the present invention. Reference is made, on the one hand, to the claims subordinate to claim 1 and, on the other hand, to the following explanation of a preferred embodiment of the invention with reference to the drawing. In conjunction with the explanation of the preferred embodiment of the invention with reference to the drawing, generally preferred embodiments and developments of the teaching are also explained. In the drawing, the sole figure shows the schematic structure of a system according to the invention that uses the method according to the invention for treating greywater into process water. The claimed control is essential.

[0034] The figure shows a schematic view of grey water coming from a shower, a bathtub, a hand basin or the kitchen being passed over or through a coarse filter, whereby the coarse filtering can use a filter with an integrated overflow.

[0035] From there, the coarsely filtered greywater flows into a greywater collection tank, which may include an aeration unit. Sediment is drained into the sewer or disposed of in another way.

[0036] The greywater tank contains a batch pump that pumps the pre-treated greywater into a greywater filtration tank. The greywater filtration tank also includes an aeration unit. From there, the further filtered greywater flows into an ultrafiltration station. The ultrafiltration station includes at least one membrane filter, which is periodically backwashed and thus cleaned, preferably at controlled intervals. The process water used for backwashing, along with the dirt particles released from the membrane filter, is fed either to the coarse filter or the greywater collection tank and undergoes further treatment.

[0037] From the ultrafiltration station, the purified grey water, i.e. the water generated as process water, is fed into a process water storage tank with a backwash pump.

[0038] The figure indicates that the process water storage tank has a fill level monitoring system. If the fill level is too low, drinking water is added (according to the specifications of EN 1717 Cat. 5 or country-specific regulations) or, alternatively, rainwater is used. This ensures that sufficient process water is always available. A pump system then supplies the process water to the appropriate consumers, e.g., for garden irrigation, flushing toilets, washing clothes, cleaning purposes, etc. All conceivable uses for process water can be realized.

[0039] The procedure is carried out in a controlled manner using relevant process parameters.

[0040] With regard to further advantageous embodiments of the device according to the invention, reference is made to the general part of the description and to the appended claims in order to avoid repetition.

[0041] Finally, it should be expressly pointed out that the above-described embodiments of the device according to the invention serve only to explain the claimed teaching, but do not limit it to the embodiments.

[0042] 1 coarse filter

[0043] 2 drinking water supply

[0044] 3 Greywater batch pump

[0045] 4 channel

[0046] 5 greywater collection tank with aeration unit

[0047] 6 Grey water filtration tank with

[0048] Ventilation unit

[0049] 7 Ultrafiltration stations

[0050] 8 process water tanks with

[0051] Backwash pump

[0052] 9 Pressure booster system

[0053] RECTIFIED SHEET (RULE 91) ISA / EP

Claims

- 9 - Claims 1. A method for treating greywater to produce process water, comprising a purification process comprising coarse filtration of the greywater, preferably aerobic biological purification with sedimentation of particles and suspended matter, and subsequent ultrafiltration, preferably by means of a membrane filter, wherein the purification process is regulated at least with regard to the biological purification and the ultrafiltration depending on the greywater contamination.

2. Method according to claim 1, characterized in that the coarse filtering has a filter with integrated overflow.

3. Method according to claim 1 or 2, characterized in that the coarsely filtered grey water is aerated in a grey water collection tank and from there is pumped into another tank - grey water tank - for further biological treatment.

4. A method according to claim 3, characterized in that the biological purification is carried out by adding wastewater bacteria and by aeration in the greywater tank.

5. A method according to claim 4, characterized in that the biologically purified grey water is fed to a station for ultrafiltration, wherein the ultrafiltration is preferably carried out by means of hollow fiber membrane filters.

6. Method according to one of claims 1 to 5, characterized in that the process water generated by the cleaning process is stored in a process water tank and from there is supplied via a pressure boosting system to one or more consumers suitable for process water use.

7. Method according to one of claims 1 to 6, characterized in that a backwash pump is provided in or on the process water tank, which is used to backwash the filter or filters of the ultrafiltration station, the backwash water being fed back into the grey water to be cleaned.

8. Method according to one of claims 1 to 7, characterized in that the control is designed so that the treatment of grey water is carried out in process water only according to actual need, thereby resulting in efficient use of the plant.

9. Method according to one of claims 1 to 8, characterized in that in the absence of a sufficient quantity of generated process water, preferably in the process water tank, drinking water is supplied, preferably controlled by a level gauge.

10. Method according to one of claims 1 to 9, characterized in that rainwater is added to the cleaning process.

11. Method according to one of claims 1 to 10, characterized in that at least the biological purification and / or the ultrafiltration or their tanks can be modularly expanded or supplemented with the respective devices.

12. Method according to one of claims 1 to 11, characterized in that the grey water and / or the at least partially treated grey water / process water is used for heat recovery.

13. Method according to one of claims 1 to 12, characterized in that the control influences the residence time of the grey water in the respective stations, the pumping rates from one station to the other and the aeration in the respective stations of the cleaning process. - 11 - 14. The method according to any one of claims 1 to 13, characterized in that the control system continuously adjusts the process parameters, in particular to ensure that the greywater is treated in a way that is gentle on the filters.

15. The method according to any one of claims 1 to 14, characterized in that the control system connects a local network controlling the system to a central network via a LAN or WLAN connection.

16. Method according to one of claims 1 to 15, characterized in that the control can be operated or influenced by remote access, preferably via mobile phone app or desktop, optionally via satellite technology.

17. Apparatus for treating grey water into process water, for applying a method according to one of claims 1 to 16.

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