System and method for purifying rainwater resources and water quality of closed water body
The technical field is as follows:
the invention belongs to the field of sponge city construction and water body comprehensive treatment, and particularly relates to a system and a method for purifying rainwater resources and closed water body water quality.
Technical background:
rainwater runoff pollution is a main component of urban non-point source pollution, and even if a shunt drainage system is adopted in a highly urban area with high ground surface pollution load, the direct drainage of initial rainwater can cause serious pollution to a receiving water body. According to related research results, the maximum value of initial rainwater pollutant indexes of certain underlying surfaces and drainage subareas is far higher than that of typical urban domestic sewage, and if the initial rainwater pollutant indexes are directly drained into a river channel, the initial rainwater pollutant indexes can pollute the water environment of the river channel and even cause black and odorous river channels. Therefore, the initial rainwater must be controlled to avoid the damage to the ecological environment such as the river channel.
The shortage of water resources is an important problem facing China all the time, and especially most northern cities are serious in resource water shortage and ecological water shortage. After water is introduced from the central line of the south-to-north water diversion, although the shortage of urban living and production water can be relieved to a certain extent, the agricultural and ecological water still has a large gap, and the future water resource supply and demand situation is still severe. Due to insufficient ecological water supply of the riverway, the water body does not flow for a long time, and the water environment deterioration is aggravated. At present, the development of conventional water resources tends to be excessive, unconventional water resources still have great development potential, rainwater resources are extremely limited to be recycled in various cities in China before sponge cities are promoted to be constructed in China, and in order to improve the water ecology of the cities, the utilization of the rainwater resources needs to be enhanced, and the basic water consumption of the ecological environment is guaranteed.
With the rapid development of the urbanization process, a lot of natural or artificial closed water bodies exist in urban water bodies, which are commonly found in urban greenbelts and parks, and because the urban water bodies are not communicated with external water systems, the self-cleaning capacity is poor, pollutants and water body animal and plant residues are accumulated all the year round, sediment accumulation is serious, no clean water source is supplied at ordinary times, and the water body ecology is damaged. If the water quality control agent is developed, not only can the ecological system be damaged, the shortage of water resources is aggravated, and the due utilization value of the water body is lost, but also the life of people and the attractiveness of the city are influenced, and the development of the city is adversely affected.
The invention content is as follows:
the invention aims to solve the technical problem of providing a system and a method for purifying rainwater resources and closed water quality, which can remove pollutants in rainwater, provide an ecological water replenishing source for a river channel, realize the resource utilization of the rainwater, mainly solve the problems of urban water environment pollution and ecological water shortage in water resource shortage areas, and simultaneously can be used for maintaining the water quality of the closed water in dry seasons.
In order to solve the problems, the invention adopts the following technical scheme:
1. a system for purifying rainwater resources and the water quality of a closed water body comprises a rainwater collecting unit, a water body processing unit and a water body purifying unit; wherein:
the rainwater collection unit consists of a regional rainwater collection pool, a rainwater pump station and a water outlet lock well consisting of a first control valve and a second control valve;
the water body treatment unit comprises a rainwater storage tank with a water level monitoring module, a fine grid, a hydraulic vortex separator, an inclined tube sedimentation tank with an online water quality monitoring module, a dosing room, a sludge storage tank and a sludge dewatering machine room;
the water body purification unit comprises a water outlet pump station, a vertical subsurface flow constructed wetland, a second submersible sewage pump and an ecological water replenishing tank;
wherein: the outlet sluice well is connected with the rainwater storage tank through a water-regulating pipeline after being lifted by a rainwater pump station, the rainwater storage tank is lifted to a fine grid through a first submersible sewage pump, and the fine grid, the hydraulic vortex separator and the inclined tube sedimentation tank are connected through a gravity flow pipeline;
the sedimentation tank is connected with the vertical subsurface flow constructed wetland through a water outlet pump station; the output end of the vertical subsurface flow constructed wetland is connected to the ecological water replenishing pool.
Further, the vertical subsurface flow constructed wetland is formed by arranging a water distribution pipe and a perforated three-stage filter material die, each stage of the filter material die consists of 8 purifying structure layers, wherein: each stage of the filtering material mould comprises a water storage layer, a covering layer, a water distribution filtering material layer, a water collection filtering material layer, a composite geomembrane, fine river sand and a concrete cushion layer from top to bottom in sequence.
Furthermore, the design parameter of the vertical subsurface flow constructed wetland is that the hydraulic load is 0.4-0.8 m3/m2D, hydraulic retention time ≥ 2d, BOD5Surface load of 6-8 g/m2·d。
Furthermore, the hydraulic vortex separator adopts a load of 150-200 m3/m2H hydrodynamic drive.
Furthermore, the sedimentation tank consists of a stirrer, a guide cylinder and an online water quality monitoring module.
Furthermore, the distance between the grid bars in the fine grid is less than or equal to 5 mm.
In order to solve the above problems, the present invention may further adopt the following technical solutions:
a method for purifying rainwater resources comprises the following steps:
s101, in the early stage of rainfall, a first control gate of a water outlet gate well is closed, a second control gate is opened, a rainwater pump station lifts rainwater and then enters a rainwater storage tank through a water regulating pipeline, so that the rainwater runoff pollution control is realized, after whether the storage tank meets a water storage requirement is judged according to a water level signal in the storage tank provided by a water level monitoring module, if the water storage requirement is met, the first control gate is closed, the second control gate is opened, and the rainwater is discharged into a river channel; otherwise, entering the step S2;
s102, lifting rainwater in the rainwater storage tank into a fine grid through a water pump, and removing floating objects and part of suspended matters in the rainwater; then the sewage enters a hydraulic vortex separator through a gravity flow pipeline, and most of sand grains in the sewage are removed by utilizing the principle of a rotational flow grit chamber; the effluent of the hydraulic vortex separator enters a sedimentation tank through a gravity flow pipeline for impurity treatment, and the water quality of the sedimentation tank is detected through an online water quality monitoring module; if the water quality requirement is met, inputting the water into a water outlet pump station;
s103, purifying the water quality by the vertical subsurface flow constructed wetland, and inputting the purified water into an ecological water replenishing pool for storage.
S104, conveying the bottom mud washed by the rainwater storage tank and the chemical sludge generated by the efficient sedimentation tank into a mud storage tank through a water pump pressure flow pipeline, then conveying the mud into a sludge dewatering machine room, and carrying out deep dewatering.
In order to solve the above problems, the present invention may further adopt the following technical solutions:
a method for purifying the water quality of a closed water body comprises the following steps:
s201, conveying the water body into a fine grid through a second submersible sewage pump by the ecological water replenishing pool in dry seasons; removing floating objects and part of suspended matters in the rainwater; then the sewage enters a hydraulic vortex separator through a gravity flow pipeline, and most of sand grains in the sewage are removed by utilizing the principle of a rotational flow grit chamber; the effluent of the hydraulic vortex separator enters a sedimentation tank through a gravity flow pipeline for impurity treatment, and the water quality of the sedimentation tank is detected through an online water quality monitoring module; if the water quality requirement is met, inputting the water into a water outlet pump station;
s202, purifying the water quality by the vertical subsurface flow constructed wetland, and inputting the purified water into an ecological water replenishing pool for storage.
S203, conveying the chemical sludge generated by flushing the bottom sludge in the rainwater storage tank and the efficient sedimentation tank into a sludge storage tank through a water pump pressure flow pipeline, then conveying the chemical sludge to a sludge dewatering machine room, and carrying out deep dewatering.
Further, in the step S2, in the rainwater impurity removing process of the sedimentation tank: adding the flocculating agent and the coagulant aid between the chemicals into the guide shell and mixing the flocculating agent and the coagulant aid by a stirrer; wherein the dosage of the flocculating agent is 50-100 mg/L (10% concentration liquid), the dosage of the coagulant aid is 0.5-1 mg/L, and the dosage is inclinedThe load of the pipe sedimentation tank is 5-8 m3/m2H, setting the water quality requirement SS of effluent to be less than or equal to 30mg/L in the online water quality monitoring module.
Advantageous effects
1. According to the characteristics of rainwater quality, the fine grids and the efficient hydraulic vortex separator in the water body treatment unit are used as a first treatment link to respectively remove floating objects, suspended matters, sand grains and the like in rainwater, so that the influence of the fine grids and the efficient hydraulic vortex separator on the operation of a subsequent efficient sedimentation tank and an artificial wetland is avoided, the dosage of chemicals is reduced, and the operation cost is reduced;
2. the invention adopts the high-efficiency sedimentation tank to further remove SS and COD in the rainwater, ensures that the inflow water quality of the constructed wetland meets the operation requirement, adopts a higher numerical value than that of the conventional sewage treatment for the hydraulic load, and can greatly reduce the occupied area; the efficient sedimentation tank ensures that the SS of wetland inlet water is less than or equal to 30mg/L by adding the medicament, can properly improve the operation load of the wetland, and reduces the floor area and the investment of the wetland.
3. The invention adopts the vertical undercurrent artificial wetland to realize that the quality of the outlet water of the rainwater meets the water quality requirements of four types of water on the surface, and is used for the ecological water replenishing of a closed water body and a peripheral river channel.
Description of the drawings:
FIG. 1 is a schematic view of a system for purifying water quality of a closed water body by using rainwater resources according to the present invention.
The specific implementation mode is as follows:
the invention is further described with reference to the following figures and embodiments.
As shown in fig. 1, the invention provides a system for purifying the water quality of a closed water body by utilizing rainwater resource, which comprises a rainwater collecting unit, a water body processing unit and a water body purifying unit; wherein:
the rainwater collection unit consists of a regional rainwater collection pool 101, a rainwater pump station 102 and a sluice well 103;
the water body treatment unit comprises a rainwater storage tank 201, a fine grid 202, a hydraulic vortex separator 203, a sedimentation tank 204, a dosing room 205, a sludge storage tank 206 and a sludge dewatering machine room 207;
the water body purification unit comprises a water outlet pump station 301, a vertical subsurface flow constructed wetland 302 and an ecological water replenishing tank 303. The ecological water replenishing tank 303 is provided with a second submersible sewage pump.
Wherein: the system is characterized in that the sluice well 103 and the rainwater storage tank 201 are lifted by an axial flow pump of a rainwater pump station and then connected through a gravity flow water transfer pipeline, the rainwater storage tank 201 is provided with a first submersible sewage pump and lifted to a fine grid 202 through the first submersible sewage pump, and the fine grid 202, the hydraulic vortex separator 203 and the sedimentation tank 204 are connected through a gravity flow pipeline;
a water outlet pump station 301 is arranged between the sedimentation tank 204 and the vertical subsurface flow constructed wetland 302; the effluent of the vertical subsurface flow artificial wetland 302 flows to an ecological water replenishing pool 303 by gravity; the ecological water replenishing pool 303 related to the invention adopts park water.
And the water body purification unit enters the fine grid 201 of the water body treatment unit through the water body of the ecological water replenishing tank 303 in dry seasons, and water body treatment is carried out according to the flow.
The fine grid 202 is mainly used for removing floating objects and suspended matters in rainwater so as to protect pipelines, valves and other facilities from abrasion and blockage, ensure the normal operation of a subsequent high-efficiency sedimentation tank and require the grid spacing to be less than or equal to 5 mm; the hydraulic vortex separator 203 is mainly used for removing particles with the diameter larger than 0.2mm and the density of 2.65t/m in sewage3Sand grains and the like, the hydraulic load of the hydraulic pump is 150 to 200m3/m2And h, hydrodynamic drive is adopted, electricity is not needed, and deslagging and desanding are more convenient.
The rainwater regulation pool 201 washes the bottom mud and the sludge generated by the high-efficiency sedimentation tank is delivered to the sludge deep dehydration machine room 207 through the water pump pressure flow of the sludge storage pool 206, and is transported outside after deep dehydration.
The sedimentation tank 204 is composed of a stirrer and a guide cylinder. The sedimentation tank 204 can improve the flocculation effect through the matched guide cylinder of the flocculation stirrer, reduce the flocculation time, improve the hydraulic load of the inclined tube sedimentation tank and greatly reduce the floor area of the whole efficient sedimentation tank. The process is as follows:
adding a flocculating agent and a coagulant aid into a stirrer and a guide cylinder to remove a large amount of suspended matters (SS) and partial COD (chemical oxygen demand) in sewage, wherein the PAC (polyaluminium chloride) adding amount is 50-100 mg/L (10% concentration liquid), the PAM adding amount is 0.5-1 mg/L, and the inclined tube sedimentation tank load is 5-8 m3/m2H, the water quality of the effluent requires SS to be less than or equal to 30mg/L, and the influence on the subsequent operation of the artificial wetland is reduced.
The vertical subsurface flow constructed wetland 303 realizes uniform water distribution through a perforated water distribution pipe. The vertical subsurface flow constructed wetland has three levels aiming at the water quality characteristic of a water body to be treated, the structure has strong impact load resistance, and the influence of temperature in the operation process is small. The constructed wetland second level and third level filter materials select the water storage and retention base material with purification performance, the pollutant removal effect is good, the water storage and retention base material is a special inorganic cementing material, the special inorganic cementing material is molded by a special foaming process, the structure is loose and porous, compared with the traditional adopted filter materials, the artificial wetland second level and third level filter materials have the characteristics of large specific surface area, strong water absorption and storage capacity and the like, and can be used for filtering impurities and purifying water quality, and the upper layer filter materials are favorable for the growth of plants.
Each level of the vertical subsurface flow constructed wetland selects a special purification structure layer which is divided into 8 layers, the thickness of the purification structure layer is 1.8m, and the purification structure layer sequentially comprises a water storage layer (namely a plant layer, the thickness of the water storage layer is 200mm), a covering layer (the particle size of a filter material is 8-16mm, the thickness of the filter material is 200mm), a water distribution filter material layer (the particle size of the filter material is 16-32mm, the thickness of the filter material is 600mm), a water collection filter material layer (the particle size of the filter material is 25-40mm, the thickness of the filter material is 600mm), 5 fine river sands (0-2mm, the thickness of the fine river sands is 50mm), a composite geomembrane (two layers are provided with one membrane), fine river sands (0-2mm, the thickness of the fine river sands is 50mm) and a concrete cushion (the thickness of 100mm) is arranged on the water distribution filter material layer.
The design parameters of the vertical subsurface flow constructed wetland are as follows: hydraulic load of 0.4-0.8 m3/m2D, hydraulic retention time ≥ 2d, BOD5Surface load of 6-8 g/m2·d。
The system comprises a dry season operation mode, and the utilization rate of the system is improved. The ecological water replenishing tank is internally provided with a second submersible sewage pump, the park water body 303 is lifted in dry seasons and enters the fine grid 202 for purification treatment according to the flow, the water quality requirement of the park water body is ensured, and the normal operation of the wetland can be maintained.
The invention has the following steps:
the axial-flow pump that 201 utilizes present situation rainwater pump station between present situation pump station play water lock well 103 and the rainwater regulation pond promotes the back, transfers the water pipe connection through gravity flow, rainwater regulation pond 201 be equipped with first dive dredge pump, promote to thin grid 202 through the water pump, thin grid 201, hydraulic vortex separator 202, high-efficient sedimentation tank 203 between connect through gravity flow pipeline, high-efficient sedimentation tank 203 and perpendicular undercurrent constructed wetland 302 between be equipped with dive and go out water pump station 301. The effluent of the vertical subsurface flow artificial wetland 302 flows to a water body by gravity and is used for an ecological water replenishing tank 303, a second submersible sewage pump is arranged in the ecological water replenishing tank 303, the water body is lifted by the second submersible sewage pump in dry seasons and sent into a fine grid, and purification treatment is carried out according to the flow. The rainwater regulation pool 201 washes the bottom mud and the sludge generated by the high-efficiency sedimentation tank is delivered to the sludge deep dehydration machine through the water pump pressure flow of the sludge storage pool 206, and is transported out after deep dehydration.
A method for purifying rainwater resources comprises the following steps:
s101, in the early stage of rainfall, a first control gate of a water outlet gate well is closed, a second control gate is opened, a rainwater pump station lifts rainwater and then enters a rainwater storage tank through a water regulating pipeline, so that the rainwater runoff pollution control is realized, after whether the storage tank meets a water storage requirement is judged according to a water level signal in the storage tank provided by a water level monitoring module, if the water storage requirement is met, the first control gate is closed, the second control gate is opened, and the rainwater is discharged into a river channel; otherwise, entering the step S2;
s102, lifting rainwater in the rainwater storage tank into a fine grid through a water pump, and removing floating objects and part of suspended matters in the rainwater; then the sewage enters a hydraulic vortex separator through a gravity flow pipeline, and most of sand grains in the sewage are removed by utilizing the principle of a rotational flow grit chamber; the effluent of the hydraulic vortex separator enters a sedimentation tank through a gravity flow pipeline for impurity treatment, and the water quality of the sedimentation tank is detected through an online water quality monitoring module; if the water quality requirement is met, inputting the water into a water outlet pump station;
further, the step of S2The rainwater impurity removing process of the sedimentation tank in the step: adding the flocculating agent and the coagulant aid between the chemicals into the guide shell and mixing the flocculating agent and the coagulant aid by a stirrer; wherein the dosage of the flocculating agent is 50-100 mg/L (10% concentration liquid), the dosage of the coagulant aid is 0.5-1 mg/L, and the load of the inclined tube sedimentation tank is 5-8 m3/m2H, setting the water quality requirement SS of effluent to be less than or equal to 30mg/L in the online water quality monitoring module.
S103, purifying the water quality by the vertical subsurface flow constructed wetland, and inputting the purified water into an ecological water replenishing pool for storage.
S104, conveying the bottom mud washed by the rainwater storage tank and the chemical sludge generated by the efficient sedimentation tank into a mud storage tank through a water pump pressure flow pipeline, then conveying the mud into a sludge dewatering machine room, and carrying out deep dewatering.
In order to solve the above problems, the present invention may further adopt the following technical solutions:
a method for purifying the water quality of a closed water body comprises the following steps:
s201, conveying the water body into a fine grid through a second submersible sewage pump by the ecological water replenishing pool in dry seasons; removing floating objects and part of suspended matters in the rainwater; then the sewage enters a hydraulic vortex separator through a gravity flow pipeline, and most of sand grains in the sewage are removed by utilizing the principle of a rotational flow grit chamber; the effluent of the hydraulic vortex separator enters a sedimentation tank through a gravity flow pipeline for impurity treatment, and the water quality of the sedimentation tank is detected through an online water quality monitoring module; if the water quality requirement is met, inputting the water into a water outlet pump station;
further, in the step S2, in the rainwater impurity removing process of the sedimentation tank: adding the flocculating agent and the coagulant aid between the chemicals into the guide shell and mixing the flocculating agent and the coagulant aid by a stirrer; wherein the dosage of the flocculating agent is 50-100 mg/L (10% concentration liquid), the dosage of the coagulant aid is 0.5-1 mg/L, and the load of the inclined tube sedimentation tank is 5-8 m3/m2H, setting the water quality requirement SS of effluent to be less than or equal to 30mg/L in the online water quality monitoring module.
S202, purifying the water quality by the vertical subsurface flow constructed wetland, and inputting the purified water into an ecological water replenishing pool for storage.
S203, conveying the chemical sludge generated by flushing the bottom sludge in the rainwater storage tank and the efficient sedimentation tank into a sludge storage tank through a water pump pressure flow pipeline, then conveying the chemical sludge to a sludge dewatering machine room, and carrying out deep dewatering.
The present invention has been described in terms of specific examples, which are provided to aid understanding of the invention and are not intended to be limiting. For a person skilled in the art to which the invention relates, several simple deductions, modifications or substitutions may be made according to the idea of the invention.