MX2007003943A - Dual wastewater treatment plant that separates soapy water or greywater from blackwater. - Google Patents

Abstract

The invention relates to a dual wastewater treatment plant which separates soapy water from blackwater and is intended to clarify and disinfect water that has already been used in housing estates in order to recycle same in houses, thereby saving up to 55% of the drinking water required in homes. The invention comprises the separation at the point of origin of soapy water, originating from sprinklers and the washing of clothes, from blackwater, originating from toilets (WC), bathroom sinks, kitchens and the washing of floors in homes. The soapy water is conveyed to a plant in which it is subjected to the following steps: stabilisation of the pH thereof; oxidisation; decantation; addition of polymers; anthracite and silica sand filtration; disinfection with ozone, sodium hypochlorite and ultraviolet light; and softening. Said water is subsequently returned to homes to be used in toilets and to wash clothes. The blackwater is conveyed to a plant in which it is subjected to the following steps: screening, sieving, digestion in an anaerobic and aerobic biological reactor, dynamic and static decantation, silica sand filtration, and disinfection with sodium hypochlorite and ultraviolet light. Said water is subsequently returned to houses to be used to water gardens, wash cars and wash floors, as well as for use in fountains. The excess blackwater recovered can be used to water communal gardens.

Description

TITLE OF THE INVENTION Dual Wastewater Treatment Plant, with separation of soapy or gray waters and sewage.

FIELD OF THE INVENTION The field of the invention of the Dual Wastewater Treatment Plant is in the housing complexes that produce soapy and black residual water. The soapy water after being treated is returned to the houses for use in toilets (hereinafter WC) and in the washing of clothes. The black water after treatment is returned to the houses for use in gardens, in car wash, washing of exterior floors and fountains.

BACKGROUND The important housing growth that is occurring in Mexico has created the need to provide potable water even in areas of insufficient supply. This need has motivated us to recover, treat and clean the residual water in accordance with water quality standards in force in our country, and then reuse it in the same houses that generated it, in order to save drinking water. Therefore, we have developed plants for the treatment of Dual wastewater, in which the soapy water that will be reused inside the same homes in the toilets, in the washing of clothes and the cold water of the showers are treated separately. On the other hand, black water is treated to be used in gardens, car washing and washing floors in homes. The water thus obtained is called "Recuperated Water". The benefit obtained is that an average of 50% of the drinking water is saved, since the other 50% that will be used will be the recovered water, coming from the soapy water and the black water that is produced in the houses.

With the DUAL system it is possible to separately treat the residual water and fully reuse it. The main benefit is that significant savings in drinking water will be obtained, in addition to promoting the awareness of the adequate use of water in the homes of our country.

DESCRIPTION OF THE INVENTION The water used in the houses must be conducted by two pipes. One of them will lead to the sewage coming from the WC, the kitchens, the bathroom tiles and the sewage of the houses. The other tubing will carry the soapy water from the showers and the laundry area. Thus, the soapy pipe will conduct said water to the WWTP of soapy water, while the sewage pipe will flow into the Wastewater Treatment Plant (hereinafter WWTP) of sewage.

Therefore, within the same WWTP will be carried out separately the treatment of the two types of water, with the purpose of obtaining water for reuse of different quality. That is to say: soapy water will obtain water that is comparable to drinking water, which will be reused in WC and laundry without risk. Black water will provide water suitable for gardening, washing cars, washing floors and fountains.

The proposed plant with Dual System, offers great advantages over the conventional system of treatment of the mixture of soapy water with black water. The soapy water plant is designed to obtain treated water of excellent quality suitable for reuse WC, in laundry, and when required for use in the cold water of showers. The good quality of treated water is due to the fact that it does not mix with black water, to avoid the presence of highly polluting or infectious agents such as fecal coniformes and helminth eggs.

To treat black wastewater, the Dual plant has an alternate treatment train with the Extended Aeration system in the activated sludge mode, which integrates new designs for the roughing of coarse, efficient biological reactors and combined systems for the Decantation of solids . It also includes disinfection systems by filtration with Arena Sílica, exposure to Ultraviolet Light and application of Sodium Hypochlorite, to guarantee water according to NOM-003-SEMARNAT-1997, suitable for watering green areas, washing yards, washing of cars and use in sources.

BENEFITS OF A DUAL WWTP 1. Savings of drinking water - up to 54% in houses of average interest. 2. Smaller size of the Sewage Treatment Plant of Aguas Negras 1. Lower operation cost than the Wastewater WWTP. 4. Reuse of the recovered soapy or black waters without risk and without aromas. 5. The cost of construction and installation of a Dual plant is similar or less than a black water plant mixed with soap. 6. The operating cost is similar between a traditional WWTP and the Dual WWTP. 7. Lower dimension of the fractionation pipes. This decreases the additional cost of the fractionation pipes that will carry the water to each of the plants. 8. Awareness of water care among users. 9. Soapy water is reused after being treated for use in toilets, and in laundry and can also be used in the cold water of showers. 0. Black water treated in garden irrigation, car washing, fountains and washing floors is reused.

REQUIREMENTS FOR INSTALLING A DUAL WWTP - Can only be installed in subdivisions with double pipes (new) - Installation of specific pipes in the houses and in the fractionation for the driving of the different types of water. That is to say, a pipeline to conduct the soapy water coming from showers, laundry and taring of the baths and another pipe for the residual black water coming from the WC, the kitchens and the sewers. - Because they are two different floors in the same space, they must have a better trained personnel. - The capacity of water to be treated in a Dual plant is larger than a traditional plant, as prevention of the various uses and customs of families and the region in which it is installed.

DESCRIPTION OF FIGURES. 1. Blackwater Treatment Plant 2. Soapy Water Treatment Plant 2. Hydrographic Tangential 3. Biological Reactor 3. Biological Reactor 4. NAWA DI Settler 6. Lamellar Decanter 7. Silica Sand Filters DESCRIPTION OF THE PROCESS OF THE INVENTION. The process to treat the soapy water consists of the following: - The treatment begins with the Stabilization of the pH, later the Oxidation of the water is carried out to facilitate its decantation and flocculation in the Primary Settler. - To the soapy water after oxidizing and remaining in the primary settler, Polymers are added and sent to the Secondary Dynamic Settlers to achieve the most efficient removal of most of the contaminants that were not removed in the primary sedimentation.

After this process it is possible to remove up to 95% solids and clarify up to 93% the water in treatment. - The treatment continues with Ozone dosing and the sending of sedimented water through deep bed filters and multiple media with mixed silica and anthracite sand packaging. - Before reusing the filtered water, it is planned to take it to a system of emission of Ultraviolet Rays as a double disinfectant protection to guarantee the best quantity of the reuse water. Subsequently, the dissolved salts of the treated water will be removed by means of an ion exchange with Cationic Resins and finally a third disinfection is added by adding Sodium Hypochlorite and it is pumped for the return to the fractionation network. So the water already purified, disinfected and softened, will be sent to the houses for reuse.

DETAILED DESCRIPTION OF THE INVENTION MOTIVATION. Waste or contaminated water must be treated before draining to care for the health of all living beings, as well as to care for the ecology, the environment and, to avoid contamination of the water table, thus favoring the obtaining of water potable. We wish to reiterate that in order to guarantee and protect the supply of drinking water, we must avoid contaminating it. The main contaminant of drinking water is waste or black water that is discarded without any treatment and without respect for the environment. In recent decades the authorities in our country have established quality standards for treated water that is authorized to return to the environment. So then, the treated water is classified into different categories: - NOM-001-SEMARNAT-1996: For Agricultural Irrigation. - NOM-002-SEMARNAT-1996: For Irrigation of Vegetables or to send by the drainage of the cities.

- NOM-003-SEMARNAT-1997: For the Irrigation of Gardens and Human Contact. Not to drink. - NOM-004-SEMARNAT-2001: For the treatment of sludge and biosolids In no case is it allowed to consider the treated water as if it were drinking water for human digestion.

The need to treat wastewater requires the construction of treatment plants. Said purification plants can be Biological, that is to say, they carry out the purification of the impurities contained in the waste water by means of the digestion with bacteria; and Physical-Chemical plants, whose operation is carried out with the use of different methods and chemical products that purify black water.

Biological plants can be aerobic or anaerobic. Aerobics produce purifying bacteria that require air to survive, while anaerobic bacteria only subsist in oxygen-lacking media.

Among the wide variety of plants developed by man, the lowest cost that generate better results are aerobic plants, among which the so-called "Extended Aeration and Activated Sludge" stand out; and the so-called SBR: Sequential Biological Reactor. Both are used in the big cities of the world to purify the residual or black water and, once they have treated the water, it is reintegrated into the environment.

At present the Wastewater Treatment Plants (WWTP) are being installed in the same place where the black water is produced, with the purpose of reusing it there, thus avoiding the construction of huge drainage networks for the shipment of the water. black water and other drainage networks for the reintegration of treated water.

It is important that the WWTPs are adequate to the size and quality of water to be treated in order to obtain the best results and the best water quality for reuse.

The purpose of our invention is to install a Dual WWTP by separately treating the wastewater from the soapy water, achieving with this the combination of an efficient and economical installation, with a low cost operation of the plant. That is to say: In the Black Water Treatment, the primary and secondary process, in which the thick grinding, the primary aerobic digestion and the secondary decantation are carried out by physical and biological means. While the tertiary process, equivalent to the disinfection and the sanitation of the water already purified, is carried out by physical-chemical means.

Soapy Water Treatment consists of using roughing, decanting, filtering, stabilization, disinfection and softening of soapy water, to obtain water equivalent to drinking water by physical and chemical means.

In conclusion, the PTAR-DUAL that we propose, turns out to be the most efficient and the most economical in its installation and in its monthly operation, comparing them with the plants that are usually installed in the world. 1. TREATMENT OF BLACK WASTEWATER. 1.1. TECHNICAL CRITERIA The technical criteria that we consider for the selection of the processes that make up the treatment train of a WWTP, start from having a clear knowledge of the characteristics of the water received for its treatment, that is, the influent.

To treat the wastewater we have taken the pre-established average values of the order of 323 mg / l of BOD5 and 320 mg / l of SST, whose differential ranges they can reach 75% variation, mainly in DB05 and SST, which are the basis of reaction biokinetics in the calculation of a plant. A biological plant of "Extended Aeration in the activated sludge modality", that is, physical in its primary and secondary process, and physical-chemical in its tertiary process for the disinfection and sanitation of water. This allows the construction of a Biological Reactor with complete mixing and continuous flow with prolonged aeration, with recirculation of sludge to maintain the food-microorganism ratio, within the optimal parameters for the adequate development of the bacterial population and at the same time absorb the increases in loads Influent contaminants. 1. 2. TABLE OF RESIDUAL WATER COMPONENTS Based on the treatment plants with activated sludge system in the prolonged aeration mode, the estimated percentages of removal of BOD5 and SST (black water impurities), are calculated according to the distribution of the Oxygen Biochemical Demand, that according to the type of contaminants present, it is required to resort to different processes of removal to obtain the projected global efficiency. 1. 3 PROPOSED TREATMENT LINE MODULE OF A PLANT OF ACTIVATED MUDS AND PROLONGED AERATION. (Figure 1) 1.3.1 PRETREATMENT Raw water will be received directly from the main collection line of the fractionation. In order to carry out roughing, initially inclined gratings with a separation of 15 mm will be installed, and flow measurement will also be carried out by an open channel sensor system in a parshall channel with a time register. For the roughing of media and fines a screening system called Tanothal Hidrotamiz is installed, which consists of a screening system with a light path of 1.5 millimeters, which will be depositing the solids directly in a lifting type container to facilitate its removal from the plant, and the rough water will be sent to the Biological Reactor installed. (Figure 3) 1. 3.2 BIOLOGICAL PROCESS The Biological Reactor is the main process of the proposed plant. In said Biological Reactor, the digestion of the impurities contained in the wastewater is carried out, exchanging for nutrients generated by the bacteria inhabiting said Reactor. Its engineering is basic and determinant for the proper functioning of the WWTP, since the bacteria inhabitants of the Biological Reactor will be aerobic and will have a maximum life time of 40 days. Likewise, the dosage of oxygen inside the Biological Reactor will have to be calculated according to the study of the sanitary biokinetics coming from the influent. A rectangular section tank will be built, based on the proportionality rule of 3W, where the digestion of the organic matter contained in the water is carried out, the aeration to induce the biological process is carried out with centrifugal positive displacement blowers and the air distribution with fine bubble tubular diffusers, which have the advantage that they do not require fixing on the floor of the tank, since the water inside the tube that retains the membrane acts as a ballast, thus facilitating any intervention that require maintenance, since the network can be extracted partially or totally without the need to empty the tank. (Figure 4) For the optimal design of a treatment plant with biological process based on Activated Sludge in the Prolonged Aeration mode, we have determined the value of the biokinetic parameters that have been obtained in the last 5 WWTP that we have built, by what for the purposes of this project and for being wastewater from urban subdivisions, have taken the average values obtained through experience in similar operations and design of other plants, such as: 1. Maximum age of mud or residence time of the biomass in the mixed liquor in the Biological Reactor: 40 DAYS. 2. Volume of Solids contained in the Mixed Liquor by Recirculation: 12,000 mgSSLM / L 3. Volume of solids contained in the Mixed Liquor of the Biological Reactor: 3,200 mg / l 4. Biomass yield rate per unit of pollutant organic matter removed 0.5 mgSSLM / mg BOD. 5. Rate of lysis or cellular or endogenous death of the biomass 0.05 Days (-1) and 6. Rule of proportionality of air consumption 950 scf / pound of BOD removed in the process or biological will generate an area of intense aeration to mix the raw water of the influent and the recirculation of sludge coming from the dynamic sedimentation, this will be complemented with an anoxic zone at the end of the process, where the development of the anaerobic bacteria will be privileged that will be the ones that conclude the process of digestion of the organic matter . Additionally, it will prevent mixed liquor extraction pumps from presenting cavitation problems due to the volume of air in the water. (Figure 5) 1. 3.3 SECONDARY SEDIMENTATION The secondary sedimentation has the purpose of initiating the separation of the solids contained in the rough water in the primary screens and digested in the Biological Reactor, which will be carried out in two sequential stages: The first stage is Dynamic Sedimentation (optional) , that allows an instantaneous separation of solids and liquids with a recirculation of sludge immediately to the Biological Reactor. Said sedimentation is controlled by reading and recording the volume of suspended solids in the mixed liquor and with the opening and closing of automatic valves; turbidity sensors and total suspended solids will be installed at the exit of the Dynamic Settlers that will allow only the passage of water with less than 25 mg / l of total suspended solids. (Figure 6) The second sequential stage is carried out in a Decanter of circular or rectangular shape with lamellar, which will allow the final separation of the solids of the mixed liquor, at this point of the process, the water is obtained with quality NOM-001-ECOL -nineteen ninety six. (Figure 7) 1. 3.4. FILTRATION WITH SILICA SAND After sedimentation in the Lamelar Decanter, the water will pass through the silica sand filters specially designed to eliminate the treated effluent, and will retain any particle or solid of between 4 and 10 microns that may remain in suspension.

In this filtering stage, the water circulates through the filter entering through the upper collector, passing through the filter bed downwards and exiting towards the water tank filtered by the lower collector. (Figure 8) The filtration cycle has been designed in accordance with the needs of the system, with all the filtration times as well as the backwash times being programmed.

The backwashing of the filters will be carried out independently in each one and will be activated by three preset parameters in an indistinct way each: • By pressure difference of the influent and the effluent. • By timing. • By volume of filtered water. In any of the three cases they will be activated automatically, always leaving the option to carry them out manually if required or if one of the first ones is out of calibration. 1. 3.5. DISINFECTION OF DECANATED AND FILTERED WATER The disinfection process has been termed as the "Tertiary Stage" of the treatment. It is necessary to carry it out since there may be living bacteria that could be harmful to humans. For this reason, we have combined the application of two high-efficiency, low-cost procedures to guarantee the disinfection of treated water to obtain water subject to NOM-003.

The two disinfection phases that we propose: 1. Online injection of the influent to the chlorine contact tank of a chlorinated compound: Sodium hypochlorite. By means of a peristaltic high-pressure automatic dosing pump. The disinfection process takes place at a predetermined contact time of 40 minutes. 2. The emission of UV (ultraviolet) rays, capable of destroying the DNA chain and the proliferation of any bacteria including helminth eggs and any other type of microseres in the development phase. 1. 3.6 RESULTS OBTAINED -The type of process proposed allows us to guarantee the expected water quality (NOM-003-SEMARNAT-1997).

-The maximum efficiency of digestion of impurities was achieved with a time of retention of the water to be treated in the Biological Reactor of 24 hours, therefore the plant is dimensioned according to the expense of the influent.

-The operation of the plant can be carried out by personnel from the same region, since its operation does not require daily supervision of engineers and, mainly, its installation will not have complex equipment or processes that required high-level profiles.

-The proposed plant has Double Safety ", since in each of the unit operations it is backed by a complementary one that guarantees the expected result without taking into account, that the plants can undergo changes in the influent, or by changes in the time of year, or by the incorporation of different turns to the housing that are incorporated into the housing colonies.

-The proposed plant has the capacity to absorb this type of variation without affecting the quality of the water output.

-The water obtained in accordance with Nom-003 is re-entered without risk to homes for use in garden irrigation, car washing, washing floors and fountains. 2. OF TREATMENT SOAPIC WATERS 2.1. MODULE OF A SOAP WATER PLANT: (Figure 2) The process train will be determined based on the information obtained from the characterization chart, in which we can detect the values susceptible to removal by the volume in which they are contained in the wastewater and with what process it is viable to achieve the expected result: a) Temperature It is estimated to receive soapy water between 20 and 29 ° C, of the permissible 40 ° C. A homogenization tank is proposed with a hydraulic retention time of at least 4 hours that will reduce the water temperature to that of the environment. b) Solids. The total solids that integrate the volatile and settleable, can reach values of 299.4 mg / l, the purpose is to reduce to less than 5 mg / l of total solids. 2. 2 PRETREATMENT. A primary solids removal system is proposed, consisting of a pH stabilization process, another oxidation process, to later send it to a circular static settler for light and heavy solids, assisted by the injection of a flocculating polymer that increases the volume and weight specific of solids to cause efficient removal. Thickener polymers and flocculating polymers will be added to the effluent obtained and then sent to the Dynamic Sdimentadores to complement the process of removing the remaining solids from the soapy water. 2. 3. FILTRATION PROCESS. The process train will continue to carry the obtained water to the deep bed filters and multiple media with mixed packaging of silica sand and anthracite of different granulometries.

The process of Filtration of the water centrifuged through Sand Silica and Anthracite is the step that will finish to clarify the soapy water. Prior to this process, the water is disinfected with the application of ozone. 2. 4 STABILIZATION. The effluent obtained will be passed through a pH sensor, where it will be possible to determine the volume of salts removal from the treated water, based on the pH reading, which in the case of raw water can reach values of 9.3 units, considered very basic for the reaction in disinfection and for reuse. The purpose will be to stabilize it, at pH 7.0. 2. 5. SOFTENING AND FINAL DISINFECTION The treated effluent that will be extracted from the storage tank will be conducted to an ultraviolet ray emission system to carry out the final disinfection and thereby destroy any polluting agent that may have survived in the water.

Afterwards, the water is softened by Cationic Resin filters and prepared for final disinfection with Sodium Hypochlorite (liquid or gaseous) and then sent to the drainage network for reuse in the houses in the WC and in the water treatment area. laundry.

Claims (1)

CLAIMS. Having sufficiently described my invention, I consider as a novelty and therefore claim as my exclusive property, what is contained in the following clauses:

1. The process of division of soapy and black wastewater to be treated independently and returned to the houses for reuse, with the purpose of saving 50% on average of the potable water that is required in homes. This process is characterized by the installation of independent pipelines, one to drive the soapy residual water from the showers and the laundry; and another to drive the black residual water from the toilets, kitchens, bathroom taps and household sewers. Soap Residual Water undergoes a process that includes: -Stabilization of pH -Oxidation of water for Decantation -Decantation and Static Flotation -Dosification of Flocculating Polymers -Dynamic Decantation -Filtering in Silica and Anthracite Sand -Overall disinfection with Ozone, with Ultraviolet Light and with Sodium Hypochlorite -Filtered with Activated Carbon (optional) -Smoisturizer with Cationic Resin The Black Residual Water is subjected to a process that includes: -Ground Screening in Grids, Desander and Screen with light passage of 1.5 mm -Digestión in Aerobic Biological Reactor in 90% Anaerobic in 10% -Decantation with Dynamic Settler and Lamelar Decanter or Circular - Disinfection with silica sand, sodium hypochlorite and ultraviolet light. Recovered soapy water is returned to the houses of the fractionation for reuse in WC and laundry. The reclaimed Black water is returned to the houses for watering gardens, washing cars, washing floors and using sources. The remaining black water is used in the irrigation of green areas of the subdivisions and for sale.