System and method for harvesting rainwater

Abstract

A system for harvesting rainwater for use in a skirt building. The skirt building includes a main building and a podium supporting the main building. The system includes: a standpipe; a buffer channel; a filter channel; and a green roof. The green roof includes a vegetation region including a baffled diversion corridor, and a bottom filtering layer including a drainage pipe. The standpipe is arranged on the main building and is connected to the buffer channel where the energy of rainwater flowing out of the standpipe is dissipated. The buffer channel, the filter channel, and the green roof are arranged on the podium, and the buffer channel communicates with the filter channel. The filter channel is connected to the green roof. The filter channel is divided into a plurality of sections respectively filled with different matrix materials.

Claims

1. A system for harvesting rainwater in a skirt building, the skirt building comprising a main building and a podium building, the podium building being disposed below the main building and supporting the main building, the system comprising: a) a standpipe; b) a buffer channel comprising a first outlet; c) a filter channel comprising a second inlet, a second outlet, and a plurality of sections; d) a green roof comprising a vegetation region, a water channel, and a bottom filtering layer; and e) a drainage pipe; wherein: the standpipe is adapted to be arranged on the main building and is connected to the buffer channel where the energy of rainwater flowing out of the standpipe is dissipated; the buffer channel, the filter channel, and the green roof are arranged on the podium building; the first outlet of the buffer channel communicates with the second inlet of the filter channel; each of the plurality of sections is filled with a matrix material, the matrix material in each one of the plurality of sections is different from that in another one of the plurality of sections; and the matrix material comprises crushed stone, coarse sand, fine sand, and slag; each one of the plurality of sections is separated from another one of the plurality of sections by grilles and geotextiles; the second outlet of the filter channel is connected to one end of the water channel; the water channel is disposed in the vegetation region; a water outlet is disposed at another end of the water channel; the bottom filtering layer is disposed below the water channel and the vegetation region; the bottom filtering layer from top to bottom comprises soil, fine gravel, pebbles, slag, and coarse gravel; and the drainage pipe is disposed inside the pebbles of the bottom filtering layer for collecting water form the bottom filtering layer.

2. The system of claim 1, further comprising a plurality of buffer belts disposed in the buffer channel, wherein the buffer channel comprises a water inlet end, a middle part, and a water outlet end; the plurality of buffer belts comprises a first buffer belt, a second buffer belt, and a third buffer belt the first buffer belt is disposed in the water inlet end; the second buffer belt is disposed in the middle part; and the third buffer belt is disposed in the water outlet end; the first buffer belt comprises a plurality of stones; each of the second buffer belt and the third buffer belt comprises a plurality of pebbles; a first volume of the plurality of stones is larger than a second volume of the plurality of pebbles; a cross section of the plurality of buffer belts is in a shape of an equilateral triangle; and the plurality of buffer belts is disposed on a bottom of the buffer channel.

3. The system of claim 1, wherein the water channel in the vegetation region is in a form of a letter S.

4. The system of claim 3, wherein the water channel is provided with ridges for separating the water channel into a plurality of water storage units.

5. The system of claim 4, wherein a height of the ridge is lower than a height of the water channel, and the ridge comprises fine gravels.

6. A method for harvesting rainwater in a skirt building using the system of claim 1, the method comprising: 1) transporting the rainwater from the standpipe of the main building to the buffer channel for energy dissipation; 2) introducing the rainwater after energy dissipation to the filter channel for preliminary filtration to yield preliminary filtered rainwater; 3) introducing the preliminary filtered rainwater flowing out of the filter channel to the water channel of the green roof for plant filtration and percolation; 4) introducing a first part of the preliminary filtered rainwater from the water channel of the green roof to the bottom filtering layer to yield secondary filtered rainwater; 5) harvesting the secondary filtered rainwater by the drainage pipe disposed inside the bottom filtering layer of the green roof; and 6) harvesting a second part of the preliminary filtered rainwater discharged from the water outlet.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows the skirt building

(2) FIG. 2 is a top view of the buffer channel, filter channel, and green roof.

(3) FIG. 3 is a side view of the buffer channel and filter channel.

(4) FIG. 4 is a side view of the green roof.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(5) For further illustrating the invention, experiments detailing a system and a method for use in a skirt building for harvesting rainwater are described below. It should be noted that the following examples are intended to describe and not to limit the invention.

(6) A system for use in a skirt building for harvesting rainwater, comprises: a standpipe 1; a buffer channel 2; a filter channel 3; and a green roof 5. The skirt building comprises a main building and a podium supporting the main building (see FIGS. 1-2). The green roof comprises a vegetation region 7 comprising a baffled diversion corridor 6, and a bottom filtering layer comprising a drainage pipe 16 (see FIGS. 2 and 4).

(7) The standpipe 1 is arranged on the main building and is connected to the buffer channel 2 where the energy of rainwater flowing out of the standpipe 1 is dissipated. The buffer channel 2, the filter channel 3, and the green roof 5 are arranged on the podium, and the buffer channel 3 communicates with the filter channel 3. The filter channel 3 is connected to the green roof 5 by a channel 4 (see FIG. 4). The filter channel 3 is divided into a plurality of sections respectively filled with different matrix materials comprising crushed stone 31, coarse sand 32, fine sand 33, and slag 34 and the sections are separated by grilles and geotextiles 35 (see FIG. 3). The bottom filtering layer from top to bottom comprises soil 11, fine gravel 12, pebble 13, slag 14, and coarse gravel 15, and exuded water from the bottom filtering layer is drained by the drainage pipe 16 (see FIG. 4); a water outlet 8 is disposed at one end of the baffled diversion corridor 6 (see FIG. 2).

(8) The buffer channel 2 is arranged in the front end of the system (see FIG. 2). The buffer channel 2 is divided into a water inlet end, a middle part, a water outlet end, each comprising a plurality of buffer belts 21. The buffer belts 21 at the water inlet end comprise stones of relatively large volumes. The buffer belts 21 at the middle part and the water outlet end comprise relatively small pebbles of different grade configurations; a cross section of the buffer belts 21 is in a shape of an equilateral triangle; and a bottom of the buffer belts 21 is fixed on a bottom of the buffer channel 2.

(9) The rainwater of the main building is transported to the water inlet end of the buffer channel 2 of the skirt building via the standpipe 1. A scale height of a top of the gravel buffer zone is lower than a scale height of a top of the buffer channel 2. A size of the buffer channel 2 is determined by a designed flow rate of the rainwater of the main building and flow rate of water outflow thereof. A slope of the buffer channel 2 is 0.3%. The water outflow is directly transported to the filter channel.

(10) The rainwater after energy dissipation by the buffer channel 2 is transported to the filter channel 3 for filtration. The filter channel 3 is filled with matrix materials of different grades, and the different matrix materials 31-34 are separated by grilles and geotextiles 35 (see FIG. 3). A length of the filter channel 3 is determined by a pollutant concentration in the rainwater water entering the filter channel 3.

(11) The green roof 5 is reconstructed from a common green roof of the skirt building. The rainwater flows in a baffled diversion corridor 6 arranged in the vegetation region of the green roof in the form of a letter S (see FIG. 2). Each baffled diversion corridor 6 is divided into a plurality of water storage units by arranging ridges 9 (see FIGS. 2 and 4). The rainwater is required to overflow the ridge 9 to enter a next water storage unit. A height of the ridge 9 is lower than a height of the baffled diversion corridor 6. The ridge 6 comprises crushed stones of a certain grade. A lower part of the green roof is provided with a filtering layer having a slope of 0.3%.

(12) The method for use in a skirt building for harvesting rainwater using the system comprises: 1) transporting the rainwater from the standpipe 1 of the main building to the buffer channel 2 for energy dissipation; 2) introducing the rainwater after energy dissipation to the filter channel 3 for preliminary interception and filtration; 3) introducing the rainwater flowing out of the filter channel 3 to the green roof 5 for plant filtration and percolation; 4) harvesting percolated rainwater by the drainage pipe 6 arranged on the bottom filtering layer of the green roof 5; and 5) harvesting the rainwater effusing from the water outlet 6 disposed at the end of the baffled diversion corridor 6.

(13) Working principle of the system for harvesting rainwater from the skirt building of the invention is as follows: the rainwater from the main building is transported to the buffer channel 2 comprising a gravel buffer zone to dissipate high energy of the rainwater, so that the flow velocity of the rainwater is decreased. The energy dissipated rainwater enters the filter channel 3 at a low flow velocity, and pollutants in the rainwater is preliminarily intercepted and filtrated, thereby decreasing the pollutant load. The rainwater outflow from the filter channel 3 is transported to the green roof 5 for plant filtration, percolation, thereby further decreasing the flow velocity. Thus, the pollutant load in the rainwater is further decreased, the percolated rainwater is harvested and utilized, and the use of rainwater outflow from the rear end of the green roof is determined according to water quality thereof.

(14) While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.