Tunnel construction wastewater integrated treatment system and treatment method

Abstract

The invention discloses a tunnel construction wastewater integrated treatment system and a treatment method. The system comprises a coagulation system, an efficient clarifier, an automatic sludge discharge system, a magnetic seed recovery system and dosing equipment, the integrated purification treatment complete equipment for the tunnel construction wastewater is divided into an on-site installation type and a mobile vehicle-mounted type according to different field conditions and use forms; in the in-situ installation mode, all the systems are manufactured into single equipment which is fixedly installed on a factory water treatment equipment site; according to the mobile vehicle-mounted type, all the systems are integrated in a container and conveyed to a site where water needs to be treated through a vehicle, convenience and rapidness are achieved, and the emergency capacity is high; the maximum processing capacity of a mobile vehicle-mounted single machine is greater than or equal to 10000 m < 3 > / d. The defects of the traditional technology in the aspects of treatment efficiency, site adaptability, operation economy, emergency response capability and the like are overcome, the practical requirements of green construction, ecological protection and up-to-standard discharge of tunnel engineering are met, and meanwhile technical reference is provided for treatment of special wastewater with similar high suspended matter and high pollution load.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of tunnel construction wastewater integrated treatment, in particular to a tunnel construction wastewater integrated treatment system and method. BACKGROUND

[0002] In the field of transportation infrastructure construction, tunnel engineering as a key component will produce a large amount of wastewater containing complex pollutants during the construction process. This kind of wastewater mainly comes from tunnel excavation, support, lining and other construction links. The water not only contains high concentration of suspended solids (SS), but also often contains heavy metal ions such as mercury, lead, cadmium and chromium. In some cases, there are also refractory organic pollutants. If directly discharged or improperly treated, it will cause serious pollution to the surrounding soil, groundwater and surface water bodies, threatening the safety of the ecological environment, and at the same time, it does not meet the strict standards of the state and local building construction wastewater discharge.

[0003] At present, the treatment technology for tunnel construction wastewater mainly refers to traditional water treatment processes, mainly including coagulation sedimentation, filtration, membrane separation and other methods. However, these technologies have many limitations in practical application and are difficult to meet the special needs of tunnel construction wastewater treatment: Firstly, the traditional coagulation sedimentation method relies on ordinary flocculants to form flocs, and the flocs have small specific gravity and slow settling velocity (usually only 1-3 m / h), which leads to low treatment efficiency, large volume of clarifiers and significant increase in land area. The construction site of the tunnel is often located in the mountainous area or the suburb of the city, and the land resource is tight. The construction of large-scale treatment facilities not only increases the construction cost, but also is difficult to arrange flexibly due to the limitation of site conditions, especially in the emergency treatment scene, which has poor adaptability.

[0004] Secondly, the existing technology has weak impact resistance. The water quality and quantity of tunnel construction wastewater are greatly affected by the construction process (such as blasting, grouting and dewatering), and the suspended solids concentration may change several times or even tens of times in a short time. The adjustment of the treatment parameters of the traditional process lags behind, which easily leads to unstable effluent quality and frequent over-standard phenomena, and a large amount of manpower is needed to monitor and adjust the operation parameters, which increases the management difficulty.

[0005] Thirdly, the operation cost and resource utilization rate are unbalanced. On the one hand, a large amount of coagulant and flocculant needs to be added to ensure the treatment effect, and the power consumption of the sludge dewatering link is high, which leads to high cost of per ton of water treatment. On the other hand, although some processes try to introduce auxiliary separation medium to improve the settling efficiency, there is no effective medium recovery mechanism. The medium is discharged with the sludge after one-time use, which not only causes resource waste, but also increases the sludge disposal cost, which does not meet the development requirements of green construction and circular economy.

[0006] Fourth, the construction period and the emergency response capability are insufficient. The traditional water treatment facilities are mostly cast in situ or installed in a scattered manner, involving civil construction, equipment assembly, pipeline connection and other links, and the construction period is as long as several months, which is difficult to quickly respond to the immediate wastewater treatment demand of tunnel construction. Especially in the emergency scenarios of sudden gushing of water in tunnel construction and sudden increase of pollutant concentration, the traditional facilities cannot be quickly deployed, which is easy to miss the best treatment opportunity and cause environmental pollution risk.

[0007] In addition, tunnel construction wastewater treatment also faces multiple contradictions such as "treatment efficiency and site adaptability", "cost control and standard discharge", "short-term emergency and long-term stable operation". For example, although the membrane separation method can achieve high-precision purification, the membrane assembly is easy to be blocked by high-concentration suspended solids, the maintenance cost is high, the service life is short, and the treatment capacity is limited, which is difficult to meet the large water demand during the peak period of tunnel construction; the filter method needs to frequently replace the filter material, the operation is complicated, and the removal effect of dissolved pollutants such as heavy metals is limited, which needs to be matched with other deep treatment units, further increasing the process complexity and investment cost. SUMMARY

[0008] Therefore, in order to solve the above problems, the present application provides a tunnel construction wastewater integrated treatment system and treatment method, which is an integrated treatment technology with high-efficiency separation, impact load resistance, low-cost operation, small land occupation, short construction period and resource recycling, to solve the problems of traditional technology in treatment efficiency, site adaptability, operation economy and emergency response capability, meet the practical needs of tunnel engineering green construction, ecological protection and standard discharge, and provide technical reference for similar high-suspended solids and high-pollution load special wastewater treatment.

[0009] The present application is implemented as follows: a tunnel construction wastewater integrated treatment system is constructed, characterized in that: the tunnel construction wastewater integrated purification treatment system comprises a coagulation system, a high-efficiency clarifier, an automatic sludge discharge system, a magnetic seed recovery system and a dosing equipment; the tunnel construction wastewater integrated purification treatment complete equipment is divided into in-situ installation type and mobile vehicle-mounted type according to different site conditions and use forms; the in-situ installation type is made into a single device, fixedly installed on the site of the water treatment equipment in the factory, and used continuously for a long time; different treatment capacity devices can be selected according to different treatment water quantity, and the combination is strong and the adaptability is wide; the mobile vehicle-mounted type integrates each system in a container, which is transported by a car to the site where water needs to be treated, which is convenient and fast and has strong emergency capability; the maximum treatment capacity of the mobile vehicle-mounted type is greater than or equal to 10,000 m3 / d.

[0010] The application discloses a tunnel construction wastewater integrated treatment system, and belongs to the field of tunnel construction wastewater treatment. The working mode of the coagulation system is as follows: the coagulation system is composed of a T1 coagulation reactor, a T2 coagulation reactor and a T3 coagulation reactor, raw water flows through the coagulation system through a water inlet; magnetic seeds, PAC and PAM are added into the coagulation system through magnetic seed adding, PAC adding and PAM adding positions respectively, and are mixed through PAC stirring and PAM stirring; the magnetic flocs (mixture of suspended matters and magnetic seeds) after stirring gradually form and grow, and the grown flocs flow out of the coagulation system through a water outlet under the driving of water flow and enter the next link.

[0011] The application discloses a tunnel construction wastewater integrated treatment system, and belongs to the field of tunnel construction wastewater treatment. The working mode of the high-efficiency clarifier is as follows: wastewater containing magnetic flocs formed in the previous process (the coagulation system) flows into the high-efficiency clarifier through a water inlet, and when the wastewater enters a working area, rapid sedimentation is realized through an inclined pipe, clear water is collected to a clear water tank through a water weir and is discharged, sludge is collected to a sludge hopper, and the sludge enters a sludge intermediate tank through an automatic sludge discharge system.

[0012] The application discloses a tunnel construction wastewater integrated treatment system, and belongs to the field of tunnel construction wastewater treatment. The working mode of the magnetic seed recovery system is that the sludge separated by the super magnetic separator is the magnetic floc formed by the magnetic seed and the suspended matter under the action of the coagulant, which is transported out of the equipment by the screw conveying device of the super magnetic separator, and then flows into the high-speed stirring unit of the magnetic seed recovery system through the pipeline, and the cutting blade is dispersed under the high-speed dispersion machine; after the magnetic seed and the suspended matter are dispersed and separated, they are mixed in the water and overflow into the magnetic separation magnetic drum, and the magnetic seed is adsorbed on the magnetic drum designed by a special magnetic circuit; the magnetic drum rotates continuously to recover the magnetic seed separated from the mixed liquid into the magnetic seed stirring tank; the non-magnetic suspended matter is discharged from the sludge discharge pipe with the water flow, and the cleaned magnetic drum enters the next cycle, and the process completes the recovery of the magnetic seed; the magnetic seed in the magnetic seed stirring tank is diluted into a solution with a certain concentration by adding water, and is continuously mixed and uniformed under the action of the magnetic seed stirring; and the magnetic seed solution is quantitatively transported to the first-stage stirring tank of the coagulation system by the magnetic seed dosing pump, so as to realize the reuse of the magnetic seed.

[0013] The integrated treatment system for tunnel construction wastewater has the characteristics that the coagulant preparation and dosing device is used for preparing and dosing PAC and PAM agents, and has simple structure and compact arrangement; the PAC preparation and dosing device is made of glass fiber reinforced plastic and is subjected to corrosion treatment; and the PAC preparation and dosing device is composed of a preparation tank, a stirrer, a valve, a liquid storage tank and a metering pump. The working mode of the dosing equipment is that the dry powder agent is weighed and then put into the preparation tank filled with clean water, and then is uniformly mixed by the stirrer; after the solution is prepared, the valve is opened to put the solution into the liquid storage tank for storage; and the metering pump of the metering unit transports the solution in the liquid storage tank to the coagulation system through the pipeline according to the requirement, so as to realize continuous and quantitative dosing.

[0014] The treatment method of the integrated treatment system for tunnel construction wastewater has the characteristics that the implementation principle is that the tunnel construction wastewater magnetic separation purification technology is to add magnetic powder with a specific gravity of 4.8-5.1 to greatly increase the specific gravity of the floc, so that efficient solid-liquid separation can be realized in the clarifier; the main processes include a magnetic flocculation reaction process, a high-speed sedimentation solid-liquid separation process and a magnetic powder recovery process; the magnetic flocculation reaction process is mainly to combine the floc and the magnetic powder to form large and dense magnetic flocs; the high-speed sedimentation solid-liquid separation process is to rely on the specific gravity of the magnetic flocs to form a sedimentation speed of more than 40 m / h in the clarifier, so as to quickly separate the pollutants from the water body; and the magnetic powder recovery process is mainly to separate the magnetic powder from the residual sludge by the high-shear machine and then make the magnetic powder enter the magnetic separator to be recycled to the loading reaction tank. The main process of wastewater purification is: After the wastewater with large suspended solids and impurities removed by pre-sedimentation treatment is lifted to the T1 coagulation reactor, PAC and magnetic seeds are added, and after sufficient flocculation, it enters the T2 coagulation reactor, PAM is added, and after coagulation, it enters the T3 coagulation reactor, forming magnetic flocs with magnetic seeds as the "core", and then enters the high-efficiency clarifier to realize rapid separation of magnetic flocs and water, achieving the purpose of water purification. Magnetic seed recovery process: The magnetic flocs are collected by the automatic sludge discharge system to the intermediate sludge tank, lifted by the magnetic seed recovery pump to the high-speed shearing machine, dispersed, and then flow through the magnetic separation magnetic drum, the magnetic seeds are adsorbed and recovered by the magnetic drum, and the remaining sludge is discharged from the bottom sludge pipe of the magnetic separation magnetic drum to the sludge tank; the recovered magnetic seeds are prepared into a solution with a certain concentration again, the amount of supplementary water required for preparing the magnetic seeds is automatically adjusted according to the height of the magnetic seed stirring tank liquid level; the magnetic seed adding pump adds the magnetic seeds to the T1 coagulation reactor according to the required amount through frequency control, completing the recycling of the magnetic seeds. Medicine adding process: The PAC and PAM required in the coagulation system are prepared into a certain concentration by the medicine preparation device PAC medicine preparation device and PAM medicine preparation device; the prepared PAC is quantitatively added to the T1 coagulation reactor by the PAC metering pump, and the prepared PAM is quantitatively added to the T2 coagulation reactor by the PAM metering pump.

[0015] The present application has the following advantages: The tunnel construction wastewater magnetic separation purification technology is to add magnetic powder with a specific gravity of 4.8~5.1 to greatly increase the specific gravity of the flocs, so that efficient solid-liquid separation can be realized in the clarifier. The main processes include magnetic flocculation reaction process, high-speed sedimentation solid-liquid separation process and magnetic powder recovery process. The magnetic flocculation reaction process is mainly to combine the pollutants into flocs and magnetic powder to form large and dense magnetic flocs. The high-speed sedimentation solid-liquid separation process is to rely on the specific gravity of the magnetic flocs to make them have a settling velocity of more than 40 m / h in the clarifier, so as to quickly separate the pollutants from the water body. The magnetic powder recovery process is mainly to separate the magnetic powder from the remaining sludge by a high-shear machine and enter a magnetic separator to recover the magnetic powder to the loading reaction tank for recycling.

[0016] Technical features: The tunnel construction wastewater integrated purification treatment technology is an advanced and reliable clarification technology, which is widely used in town domestic sewage plant upgrading and reconstruction, black and odorous water body treatment, difficult-to-degrade organic pollutant pretreatment, oilfield wastewater, heavy metal wastewater and other fields. This technology has the following characteristics: Strong impact load resistance: under the condition of water quality and water quantity change, by adjusting the formula or adjusting the water treatment agent adding amount, the treated effluent can stably meet the standard; Low operating cost: the total power consumption of sludge dewatering is 3 / 4 lower than that of conventional treatment process, and the operating cost is 30-40% lower; Short construction period: modular equipment, integrated Chengdu, fast start-up time, short construction period; Small land occupation: the land occupation is 1 / 3 of that of traditional coagulation and clarification method, saving a large amount of land resources, and being particularly suitable for areas with tight land resources; Simple operation and management: the integrated treatment equipment is a modular or skid-mounted equipment, which is simple to operate and maintain, has few operating personnel, long service life, short construction period, and is easy to expand and relocate.

[0017] Application field: the integrated purification treatment technology for tunnel construction wastewater is developed and designed for the treatment of difficult-to-settle suspended matter in water. It is mainly applied to municipal sewage, mine water, river water, oilfield produced water, landscape water and water pollution accident treatment.

[0018] Upgrading and reconstruction of municipal domestic sewage plant: deep phosphorus removal, turbidity removal and suspended solids removal.

[0019] River and basin pollution water purification and restoration: phosphorus removal, turbidity removal, suspended solids removal and COD reduction.

[0020] Heavy metal wastewater treatment: suspended solids removal, effectively removing mercury, lead, cadmium, chromium, zinc, copper, cobalt, nickel, tin and arsenic.

[0021] Treatment of high-suspended solids and difficult-to-settle water: pretreatment of landfill leachate, coking wastewater, dyeing wastewater, papermaking wastewater, oilfield wastewater and stone wastewater. BRIEF DESCRIPTION OF DRAWINGS

[0022] Fig. 1 is a process flow diagram of the integrated purification treatment technology for tunnel construction wastewater; Fig. 2 is a device structure diagram of the magnetic seed recovery system; Fig. 3 is a schematic diagram of the dosing equipment in the present application. DETAILED DESCRIPTION

[0023] The present application will be described in detail below with reference to the accompanying drawings Figs. 1-3 The technical solutions in the embodiments of the present application will be described in detail, and it is obvious that the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0024] The present application provides an integrated treatment system and method for tunnel construction wastewater, which combines Figs. 1-3 As shown in the drawings, the present application can be implemented in the following manner; 1. Integrated purification treatment technology for tunnel construction wastewater 1.1 Technical principle: The magnetic separation purification technology for tunnel construction wastewater is achieved by adding magnetic powder with a specific gravity of 4.8-5.1, which greatly increases the specific gravity of the floc, so that efficient solid-liquid separation can be achieved in the clarifier.

[0025] The main processes include magnetic flocculation reaction process, high-speed sedimentation solid-liquid separation process, and magnetic powder recovery process. The magnetic flocculation reaction process is mainly to combine the pollutants and magnetic powder to form large and dense magnetic flocs. The high-speed sedimentation solid-liquid separation process relies on the specific gravity of the magnetic flocs to achieve a settling velocity of more than 40 m / h in the clarifier, so as to quickly separate the pollutants from the water body. The magnetic powder recovery process is mainly to separate the magnetic powder and residual sludge by a high-shear machine and enter the magnetic separator to recover the magnetic powder to the loading reaction tank for recycling.

[0026] 1.2 Technical features: The integrated purification treatment technology for tunnel construction wastewater is an advanced and reliable clarification technology, which is widely used in upgrading and reconstruction of municipal sewage treatment plants, treatment of black and odorous water bodies, pretreatment of refractory organic pollutants, oilfield wastewater, heavy metal wastewater, etc. This technology has the following characteristics: Strong impact load resistance: Under the condition of water quality and quantity change, by adjusting the formula or adjusting the dosage of water treatment agent, the effluent after treatment can meet the standard stably; Low operating cost: The total power consumption of sludge dewatering is 3 / 4 lower than that of conventional treatment process, and the operating cost is 30-40% lower; Short construction period: Modular equipment, integrated Chengdu, fast start-up time, short construction period; Small land occupation: The land occupation is 1 / 3 of that of traditional coagulation and clarification method, saving a lot of land resources, especially suitable for areas with tight land resources; Simple operation and management: The integrated treatment equipment is a modular or skid-mounted device, which is easy to operate and maintain, requires fewer operators, has a long service life, short construction period, and is easy to expand and relocate; Application field: The integrated purification treatment technology for tunnel construction wastewater is designed for the treatment of difficult-to-settle suspended solids in water. It is mainly used for municipal water, mine water, river water, oilfield produced water, landscape water, and water pollution accident treatment.

[0027] Upgrading and reconstruction of municipal sewage treatment plants: deep phosphorus removal, turbidity removal, and suspended solids removal.

[0028] River and watershed pollution water purification and restoration: phosphorus removal, turbidity removal, suspended solids removal, and COD reduction.

[0029] Heavy metal wastewater treatment: suspended solids, effective removal of mercury, lead, cadmium, chromium, zinc, copper, cobalt, nickel, tin and arsenic and other heavy metals.

[0030] High suspended solids, difficult to precipitate water treatment: landfill leachate, coking wastewater, printing and dyeing wastewater, papermaking wastewater, oilfield wastewater, stone wastewater pretreatment.

[0031] 2、Process flow Fig. 1 Tunnel construction wastewater integrated purification treatment technology process 2.2、Process flow 2.2.1 Purification main process of wastewater: after the pretreatment of removing larger suspended solids and impurities, the wastewater is lifted to the T1 coagulation reactor, PAC and magnetic seeds are added, and after sufficient flocculation reaction, it enters the T2 coagulation reactor, PAM is added, and after coagulation, it enters the T3 coagulation reactor, forming magnetic flocs with magnetic seeds as "nucleus", then entering the high-efficiency clarifier, realizing the rapid separation of magnetic flocs and water, and achieving the purpose of water purification.

[0032] 2.2.2 Magnetic seed recovery process: magnetic flocs are collected to the transfer sludge tank by the automatic sludge discharge system, and are lifted to the high-speed shearing machine by the magnetic seed recovery pump, dispersed, and then flow through the magnetic separation magnetic drum. The magnetic seeds are adsorbed and recovered by the magnetic drum, and the remaining sludge is discharged from the bottom sludge pipe of the magnetic separation magnetic drum to the sludge tank. The recovered magnetic seeds are prepared into a solution with a certain concentration again, and the supplementary water required for preparing the magnetic seeds is automatically adjusted in size according to the height of the magnetic seed stirring tank liquid level. The variable magnetic seed adding pump adds the required amount to the T1 coagulation reactor through frequency control, completing the recycling of magnetic seeds.

[0033] 2.2.3 Drug adding process: PAC and PAM required in the coagulation system are prepared into a certain concentration by the PAC and PAM preparation devices. The prepared PAC is quantitatively added to the T1 coagulation reactor by the PAC metering pump, and the prepared PAM is quantitatively added to the T2 coagulation reactor by the PAM metering pump.

[0034] 3、The following describes the tunnel construction wastewater integrated purification treatment complete equipment system of the present application; the tunnel construction wastewater integrated purification treatment complete equipment mainly comprises a coagulation system, an efficient clarifier, an automatic sludge discharge system, a magnetic seed recovery system and a dosing device. The tunnel construction wastewater integrated purification treatment complete equipment produced by the company at present is divided into in-situ installation type and mobile vehicle-mounted type according to different site conditions and use forms. The in-situ installation type is fixedly installed in the site of the water treatment equipment in the factory area for long-term continuous use. Different treatment capacity devices can be selected according to different water treatment capacities, and the combination is strong and the adaptability is wide. The mobile vehicle-mounted type integrates each system in a container and is transported by a vehicle to the site where water needs to be treated, which is convenient and fast and has strong emergency capability. The maximum treatment capacity of the mobile vehicle-mounted type is ≥10000m3 / d.

[0035] 3.1 Coagulation system 3.1.1 Composition of the coagulation system: The coagulation system is the key equipment for realizing the micro-magnetic coagulation technology. The tunnel construction wastewater integrated purification treatment complete equipment uses efficient clarification to separate suspended solids, and adds special magnetic seeds (magnetic powder) to the raw water, so that the magnetic seeds form magnetic flocs with the suspended solids in the raw water under the action of the coagulant. The formed flocs are a mixture of magnetic seeds and suspended solids with the magnetic seeds as the "core". The coagulation system provides the necessary mechanical stirring and hydraulic retention time for coagulation reaction.

[0036] 3.1.2 Working principle of the coagulation system: The coagulation system is composed of T1 coagulation reactor, T2 coagulation reactor and T3 coagulation reactor. The raw water flows through the coagulation system through the water inlet. The magnetic seeds, PAC and PAM are added to the coagulation system through the magnetic seed dosing, PAC dosing and PAM dosing positions respectively, and are mixed by PAC stirring and PAM stirring. The magnetic flocs (a mixture of suspended solids and magnetic seeds) after stirring gradually form and grow, and the grown flocs are carried out of the coagulation system by the water outlet into the next link.

[0037] 3.2 Efficient clarifier 3.2.1 Composition of the efficient clarifier: The efficient clarifier is the core equipment of the tunnel construction wastewater integrated purification treatment technology. It mainly comprises an inclined pipe, a water outlet tank, a sludge hopper, an automatic sludge discharge system and a flushing system.

[0038] 3.2.2 Working principle of the efficient clarifier: The wastewater containing the magnetic flocs formed in the previous process (coagulation system) flows into the working zone through the inlet pipe. When it enters the working zone, it realizes rapid sedimentation through the inclined pipe. The clear water is collected in the clear water tank and discharged, and the sludge is collected in the sludge hopper and enters the sludge transfer tank through the automatic sludge discharge system.

[0039] 3.3 Magnetic seed recovery system 3.3.1 Composition of magnetic seed recovery system: In the previous coagulation system, magnetic seed is added to make the flocculation formed by coagulation to carry magnetic. Since the process of adding magnetic seed is continuous, the added magnetic seed will also become part of the operating cost. In order to save resources and also consider the operating cost of tons of water treatment, the magnetic seed recovery technology is developed at the same time, which can recover and reuse the magnetic seed added to the wastewater. The magnetic seed recovery system is mainly composed of flocculation dispersion machine, magnetic separation magnetic drum, magnetic seed stirring tank and magnetic seed metering and adding unit. Fig. 2 is the equipment structure diagram of magnetic seed recovery system.

[0040] 3.3.2 Working principle of magnetic seed recovery system: As shown in Fig. 2 , the sludge separated by the super-magnetic separator is the magnetic flocculation formed by the magnetic seed and suspended matter under the action of coagulant. After being transported out of the equipment by the screw conveying device of the super-magnetic separator, it enters the high-speed stirring unit of the magnetic seed recovery system through the pipeline. The cutting blade is dispersed under the high-speed dispersion machine 2. After the magnetic seed and suspended matter are dispersed and separated, they are mixed in water and overflow into the magnetic separation magnetic drum. The magnetic seed is adsorbed on the magnetic drum 3 designed by a special magnetic circuit. The magnetic drum continuously rotates to recover the magnetic seed separated from the mixed liquid into the magnetic seed stirring tank. The non-magnetic suspended matter is discharged by the sludge discharge pipe 8 with water flow, and the cleaned magnetic drum enters the next cycle. This process completes the recovery of the magnetic seed. The magnetic seed in the magnetic seed stirring tank 7 is diluted to a certain concentration by adding water, and is continuously mixed and uniformed by the magnetic seed stirring 4. The magnetic seed adding pump 6 quantitatively delivers the magnetic seed solution to the first-stage stirring tank of the coagulation system, realizing the reuse of the magnetic seed.

[0041] 3.4 Dosing equipment 3.4.1 Composition of dosing equipment: The coagulant preparation and adding device is used to prepare and add PAC and PAM reagents. It has simple structure and compact arrangement. The PAC preparation and adding device is made of glass steel for corrosion protection. It is composed of preparation tank 21, stirring machine 22, valve 23, liquid storage tank 24, metering pump 25 and other parts. As shown in Fig. 3 is the implementation structure diagram of dosing equipment.

[0042] 3.4.2 Working principle of dosing equipment: As shown in Fig. 3 , after the dry powder reagent is weighed, it is put into the preparation tank 21 filled with clean water, and is mixed uniformly by the stirring machine 22. After the solution is prepared, it is placed in the liquid storage tank 24 by opening the valve 23. The metering pump 25 of the metering unit delivers the solution in the liquid storage tank to the coagulation system through the pipeline according to the requirements, realizing continuous and quantitative addition.

[0043] Four, the use of the equipment system is described as follows: 4.1 Preparation before operation: 4.1.1 Add lubricating oil to the specified position of each speed reducer according to the requirements of the speed reducer instruction manual, and add lithium grease to the gears.

[0044] 4.1.2 Check whether each part of the pipeline and equipment is intact and clean up the debris.

[0045] 4.1.3 Check whether all connection points in the electric control box are tightened and whether the grounding is good.

[0046] 4.1.4 Before the system runs, check whether the current range of the relay is reasonably configured.

[0047] 4.1.5 Check whether the screws of each device are tightened, and fill the oil cups of each bearing seat with lubricating oil. 4.1.6 Check the opening state of each switch, and the specific opening state is as follows: The emptying valve of the coagulation system is closed.

[0048] The manual butterfly valve of the high-efficiency clarification sludge discharge system is opened.

[0049] The emptying valve of the magnetic seed recovery system is closed.

[0050] The emptying valve of the dosing system is closed.

[0051] 4.2 Empty load trial run: 4.2.1 Test the machine for each part of the electrical equipment, check whether the running direction of each motor is correct, and measure the no-load current of each electrical equipment to check whether the current is within the rated current. If there is an abnormality, it should be handled in time.

[0052] 4.2.2 After the point-by-point trial run, enter the linkage trial run.

[0053] 4.3 Water test: Before the system runs, the dosing pumps for each reagent and magnetic seed should be calibrated and compared. Before water is passed, the equipment and the corresponding containers should be tested for leaks to ensure that the system is leak-free before running under load.

[0054] 4.3.1 Pipeline leak test: Pass water through each incoming water supply pipeline and check whether the pipeline is leaking. Start the water inlet pump and check whether the water inlet pipeline is leaking. Observe whether the electromagnetic flowmeter display is normal and consistent with the control panel display. If there is a problem, it should be handled in time.

[0055] 4.3.2 Dosing equipment leak test: Open the valve to add water to the preparation mixing tank, observe whether there is a leak, open the metering pump for water test, check whether the metering pump is running and adding normally, and whether there is a water leakage phenomenon in the pipeline.

[0056] 4.3.3 Coagulation system leak test: the water inlet is pumped or flows into the coagulation system, and then overflows from the coagulation system to the inlet of the super magnetic separator. Observe whether there is water leakage in the pipes and water tanks during the whole process.

[0057] 4.3.4 High-efficiency clarification leak test: turn on the air compressor. When the pressure reaches the required value (the air compressor motor stops working), close all air solenoid valves, and then test the water inlet for leaks.

[0058] 4.3.5 Magnetic seed recovery system leak test: add clean water to the high-speed dispersion tank, magnetic separation magnetic drum, and magnetic seed stirring tank. Observe whether there is leakage in the tank body, seal, emptying, and deslagging pipelines, and whether the motors are operating normally. Turn on the magnetic seed dosing pump (peristaltic pump) and check whether the pump is operating and adding normally, and whether there is water leakage in the pipeline.

[0059] 4.4 Load operation 4.4.1 Preparation of reagents: Reagent concentration: PAC preparation concentration 10%, PAM preparation concentration 0.1%, magnetic seed concentration 10% (the concentration of reagents can be adjusted according to actual conditions). When preparing the concentration, it should be 80% of the height of the preparation tank to avoid spilling of reagents during preparation.

[0060] 4.1.2 Matters needing attention in preparation of reagents: (1) Ensure that the preparation tank is clean before preparing the reagents.

[0061] (2) During the preparation of PAC, ensure that the stirring time is about 1 hour to ensure that the reagents are completely dissolved.

[0062] (3) During the preparation of PAM, adjust the speed of the dry powder dosing equipment and the water inflow to ensure that PAM does not form clumps and is difficult to dissolve, and that PAM solids are completely dispersed and uniform in clean water.

[0063] 4.5 Control of reagents 4.5.1 Specifications of reagents: PAC: active ingredient greater than 30%; PAM: non-ionic, molecular weight greater than 12 million; magnetic seed: four-iron oxide powder, particle size 200 mesh.

[0064] 4.5.2 Preparation of reagents: PAC preparation: prepare a concentration of 10%. Close the valve at the outlet of the reagent preparation tank, turn on the tap water, and close the tap water when the water level reaches the highest point of the liquid level meter. Turn on the stirrer, add 6 bags (150 kg) of PAC dry powder to the reagent preparation tank, stir for half an hour, and then discharge the prepared solution to the reagent storage tank through the outlet.

[0065] PAM configuration: configuration concentration 1.5%, PAM agent configuration open automatically, open the tap, by adjusting the valve opening, the water flow control at 1.5m³ / h.

[0066] Magnetic seed configuration: configuration concentration 10%, open the tap, when the magnetic seed stirring tank liquid level reaches 0.75m, close the tap, open the stirrer, put in 8 bags (200kg) of magnetic seeds. After normal operation, 1~2 bags of magnetic seeds are added to each set of equipment per day (added to the magnetic seed stirring tank).

[0067] 4.5.3 Water quality commissioning: through the agent dosing, observe the floc, the size is about 2mm, and the water quality is clear. The magnetic seed dosage is about 1~1.5 times of the suspended solids (SS) of the influent water [the ratio can be relaxed to 2 times for poor water quality], and the ratio of PAM to PAC can be controlled at 1:10~1:20 (the specific ratio is adjusted according to different water quality). The effluent water quality and floc formation should be observed in time during operation, and the floc formed after adding PAM should be large and can quickly settle, and the agent dosage should be adjusted in time.

[0068] According to the initial commissioning, the PAC dosing concentration is 20ppm, the metering pump opening is 30%~40% at the influent flow rate of 830m³ / h; the PAM dosing concentration is 1.5PPM, and the metering pump opening is 65%~75%. The magnetic seed dosing concentration is 100ppm, and the magnetic seed dosing pump is frequency controlled, and the frequency is controlled at 30~35Hz.

[0069] 4.5.4 Agent dosing adjustment: adjust the agent dosing amount according to the effluent and flocculation; when the effluent is turbid, check the floc: 1) if the floc is small, but the water quality is clear, increase the PAM dosing amount; 2) if the floc size is appropriate (about 2mm), the water quality is clear, and the flocculation tank appears floc overflow, then supplement the magnetic seeds; 3) if the floc size is appropriate (about 2mm), the water quality is turbid, increase the PAC dosing amount.

[0070] The above description of disclosed embodiments enables those skilled in the art to carry out or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An integrated wastewater treatment system for tunnel construction, characterized in that; The integrated purification and treatment system for tunnel construction wastewater includes a coagulation system, a high-efficiency clarifier, an automatic sludge removal system, a magnetic seed recovery system, and dosing equipment. Depending on site conditions and usage, the complete set of integrated purification and treatment equipment for tunnel construction wastewater is divided into two types: on-site installation and mobile vehicle-mounted installation. The on-site installation system manufactures each system as a single unit, which is fixedly installed at the plant's water treatment site for long-term continuous use. Different treatment capacities can be selected according to the different volumes of water to be treated, offering strong versatility and wide adaptability. The mobile vehicle-mounted system integrates all systems within a container and is transported by truck to the site requiring water treatment, offering convenience, speed, and strong emergency response capabilities. The maximum treatment capacity of a single mobile vehicle-mounted unit is ≥10,000 m³ / d.

2. The integrated treatment system for tunnel construction wastewater according to claim 1, characterized in that; Composition of the coagulation system: The coagulation system is the key equipment for realizing micro-magnetic coagulation technology; the integrated purification and treatment equipment for tunnel construction wastewater adopts efficient clarification and separation of suspended solids, and adds special magnetic seeds (magnetic powder) to the raw water, so that the magnetic seeds and suspended solids in the raw water form magnetic flocs under the action of coagulants; the formed flocs are a mixture of magnetic seeds with magnetic seeds as the "core" and suspended solids; while the coagulation system provides the necessary mechanical stirring and hydraulic retention time for the coagulation reaction; The coagulation system works as follows: The coagulation system consists of three coagulation reactors: T1, T2, and T3. Raw water flows through the coagulation system via the inlet. Magnetic seeds, PAC, and PAM are added to the coagulation system through three separate points: magnetic seed addition, PAC addition, and PAM addition. The mixture is stirred by PAC and PAM. After stirring, magnetic flocs (a mixture of suspended solids and magnetic seeds) gradually form and grow. The grown flocs are carried by the water flow and flow out of the coagulation system through the outlet to enter the next stage.

3. The integrated wastewater treatment system for tunnel construction according to claim 1, characterized in that; The high-efficiency clarifier is the core equipment of the integrated purification and treatment technology for tunnel construction wastewater; it mainly consists of inclined tubes, effluent troughs, mud hoppers, automatic mud discharge systems, and flushing systems. The working principle of the high-efficiency clarifier is as follows: wastewater containing magnetic flocs formed in the previous process (coagulation system) flows in through the inlet through the pipe. After entering the working area, it settles quickly through the inclined tube. The clean water is collected from the outlet weir to the clean water tank and discharged, while the sludge is collected to the sludge discharge hopper and enters the sludge transfer tank through the automatic sludge discharge system.

4. The integrated treatment system for tunnel construction wastewater according to claim 1, characterized in that; Composition of the magnetic seed recovery system: In the aforementioned coagulation system, magnetic seeds were added to imbue the resulting flocs with magnetism. Since the addition of magnetic seeds is a continuous process, the added seeds also become part of the operating costs. To conserve resources while considering the operating cost per ton of water treated, the ultramagnetic separation wastewater purification technology has also developed magnetic seed recovery technology, enabling the recovery and reuse of magnetic seeds added to the wastewater. The magnetic seed recovery system mainly consists of a floc disperser, a magnetic separation drum, a magnetic seed mixing tank, and a magnetic seed metering and dosing unit. The working method of the magnetic seed recovery system is as follows: The slag separated by the super magnetic separator is magnetic flocs formed by magnetic seeds and suspended matter under the action of coagulant. After being transported out of the equipment by the spiral conveyor of the super magnetic separator, it flows into the high-speed stirring unit of the magnetic seed recovery system through the pipeline. The cutting blades disperse it under the high-speed disperser (2). After the magnetic seeds and suspended matter are broken apart and separated, they are mixed in water and overflow into the magnetic separation drum. The magnetic seeds are adsorbed on the magnetic drum (3) with a special magnetic circuit design. The magnetic drum rotates continuously and recovers the magnetic seeds separated from the mixture into the magnetic seed stirring tank. The non-magnetic suspended matter is discharged with the water flow through the sludge discharge pipe (8). The cleaned magnetic drum enters the next cycle. This process completes the recovery of magnetic seeds. The magnetic seeds are diluted into a solution of a certain concentration in the magnetic seed stirring tank (7) by water replenishment. They are continuously mixed evenly under the action of magnetic seed stirring (4). The magnetic seed addition pump (6) quantitatively delivers the magnetic seed solution to the first stage stirring tank of the coagulation system to realize the reuse of magnetic seeds.

5. The integrated treatment system for tunnel construction wastewater according to claim 1, characterized in that; The coagulant preparation and dosing device is used to prepare and add PAC and PAM agents; it has a simple structure and compact layout; the PAC preparation and dosing device is made of fiberglass for corrosion protection; it consists of several parts such as preparation tank (21), mixer (22), valve (23), storage tank (24), metering pump (25); The working method of the dosing equipment is as follows: after weighing the dry powder agent, it is put into the preparation tank (21) filled with clean water and mixed evenly by the mixer (22); after the solution is prepared, it is placed into the storage tank (24) by opening the valve (23); the metering pump (25) of the metering unit delivers the solution in the storage tank to the coagulation system as required through the pipeline to achieve continuous quantitative dosing.

6. A treatment method for the integrated treatment system for tunnel construction wastewater according to claim 1, characterized in that; The implementation principle is as follows: The magnetic separation and purification technology for tunnel construction wastewater involves adding magnetic powder with a specific gravity of 4.8~5.1, which greatly increases the specific gravity of the flocs, thereby achieving efficient solid-liquid separation in the clarification tank. The main processes include magnetic flocculation reaction, high-speed sedimentation solid-liquid separation, and magnetic powder recovery. The magnetic flocculation reaction mainly combines pollutants into flocs with magnetic powder to form large and dense magnetic flocs. The high-speed sedimentation solid-liquid separation relies on the specific gravity of the magnetic flocs themselves, which enables them to form a sedimentation velocity of over 40 m / h in the clarification tank, thereby quickly separating pollutants from the water. The magnetic powder recovery process mainly uses a high-shear machine to separate the magnetic powder from the residual sludge and bring it into the magnetic separator, where the magnetic powder is recycled back to the loading reaction tank for reuse. Main process of wastewater purification: After pre-sedimentation to remove larger suspended solids and impurities, the wastewater is pumped to the T1 coagulation reactor, where PAC and magnetic seeds are added. After full flocculation reaction, it enters the T2 coagulation reactor, where PAM is added. After coagulation, it enters the T3 coagulation reactor to form magnetic flocs with magnetic seeds as the "nucleus". Then it enters the high-efficiency clarifier to achieve rapid separation of magnetic flocs from water and achieve the purpose of water purification. Magnetic seed recycling process: Magnetic flocs are collected by an automatic sludge discharge system to a transfer sludge tank. After being dispersed by a magnetic seed recovery pump and lifted by a high-speed shearing machine, they flow through a magnetic separation drum. The magnetic seeds are adsorbed and recovered by the drum, and the remaining sludge is discharged from the bottom sludge pipe of the magnetic separation drum to the sludge tank. The recovered magnetic seeds are then prepared into a solution of a certain concentration. The amount of water required for preparing the magnetic seeds is automatically adjusted according to the liquid level in the magnetic seed mixing tank. A variable magnetic seed dosing pump, controlled by frequency, adds the required amount to the T1 coagulation reactor, completing the recycling of the magnetic seeds. Chemical dosing procedure: The PAC and PAM required in the coagulation system are prepared to a certain concentration by the PAC preparation device and the PAM preparation device. The prepared PAC is quantitatively added to the T1 coagulation reactor by the PAC metering pump, and the prepared PAM is quantitatively added to the T2 coagulation reactor by the PAM metering pump.

Images