Rainwater Management System

LESSO Helps the Construction of Sponge Cities Rainwater Management System · Rainwater Recycling

RAINWATER SYSTEM

Sponge City: Rainwater Harvesting and Utilization

CONTENTS

LESSO Profile

O LESSO History

LESSO Research Institute & Testing Center

Established in 1986, LESSO (Stock Code: 02128.HK) is a global leader in home furnishings and building materials. The Group's business portfolio spans plastic piping, building materials and home furnishings, environmental protection,new energy, supply-chain service platforms and others.lt offers a wide range of products such as pipes,photovoltaics,plumbing and sanitary ware,integral kitchen materials,integral doors and windows，aluminum formwork and smart scaffolds, water purifiers,water-proofing materials and sealants,fire-fighting equipment,valves，cables,lighting，hygiene materials，items for environmental protection, agricultural facilities, and oceanic aquaculture cages. In 2023,LESSO's salesrevenue reached overUSD4.38billion.

LESSO College

Training Apartment

Since implementing a strategy of globalization and expanding its global presence, LESSO has evolved into a sophisticated multinational. It boasts more than 30 advanced production bases worldwide,broadening its industrial and sales networks to cover Asia, North America, South America,Europe, Africa, and Oceania. This enables LESSO to provide quality products and services for global customers in accordance with its continuously improved strategic layout in a timely and efficient way.

LESSO has founded its R&D center with more than 1,oo0 scientific researchers, nationally accredited enterprise technology center, and two post-doctoral workstations to support its innovation and technical development.The Group hastaken aleadingrole in the revision of over 120 international and Chinese industry standards.LESSO owns over 2,900 patents (some of them are pending), and provides over 10,000 varieties of products, making it one of the most comprehensive manufacturers in the piping industry. Its products are utilized globally in different areas,including home decoration,civil construction,municipal water supply，drainage，energy management,power supply and telecommunications，gas supply，firefighting,environmental protection,agriculture,oceanic aquaculture,etc.

True to its idea of “Envisioning the Better, Building the Future”, LESSO remains committed to creating a better living environment, and advocating ideal cities featuring greenness, livability, and efficiency. With concerted efforts from various sectors, LESSO will fully play its role in sustaining healthy and beautiful spaceso thatglobal residentscould enjoya comfortablelife.

Sponge City -- Foreword

With the rapid development of urbanization in China, remarkable achievements have been made in urban construction, yet various issues such as high development intensity and hard paving also emerge. In particular,the construction of facilities like building roofs, roads, and squares has led to excessive hardening of the underlying surfaces, resulting in the changes in the original natural ecological background characteristics of cities. Morethan 70% 80% of rainfal forms the runoff that is directly discharged into sewers. Consequently,cities experience inevitable waterlogging during heavy rain and immediate drought after rain,resulting in water issues including deteriorated water ecology, water scarcity, water pollution, and insufficient water security.Theseissues seriously affect people's lives and work,and orderly operations of cities.

Sponge city refers to an urban development model that effectively controls rainwater runoff and achieves natural accumulation, infiltration, and purification by strengthening urban planning and construction management, and fully leveraging the rainwater absorption, storage, infiltration, and slow-release capabilities ofecosystemssuch asbuildings,roads,greenspaces,and watersystems.

Construction objectives of sponge cities in China are as follows: According to the Guiding Opinions of the General Office of the State Council on Promoting Building Sponge Cities(Document No.75[2015]of the General Office of the State Council),the construction of sponge cities was proposed to aim tominimize theimpact of urban development and construction on the ecological environment andrealize thelocal absorption andutilizationof 70% of rainfallbycomprehensivelyimplementing measures such as infiltration,retention,storage,purification,utilization,and discharge.By2020,morethan 20% of urban built-up areas should meet the target requirements, and by 2030, over 80% ofurbanbuilt-upareas shouldmeethetargetrequirements.

The Schematic Diagram for the Harvesting and Release of Water Circulation in a Sponge City

Throughout the whole construction process,we can provide one-stop solutions for sponge cities, involving overall design, construction, operation, and other aspects:

1. A dedicated design for sponge cities

The construction of a sponge city consists of three parts: low impact development (LiD）rainwater system，urban storm sewer system，and runoffdischargesystemfor excessiverainwater.These three systems complement and dependoneachother,and areimportantbasicelements fortheconstructionofaspongecity.

TheLiDrainwatersystemcanachievethefunctionssuchasrainwater infiltration，storage，regulation，transfer，pollutant interception，and purificationinbuildings,residential communities,urbanroads,urbangreen spaces,squaresandotherareasthroughmeasuressuchaspermeable pavements，green roofs，and sunken green spaces，thus effectively controlling the total runoff,peak runoff,and runoff pollution.

The urban storm sewer system,a traditional residential community and municipal drainage system,works with the LID rainwater system to achieve the harvesting,transfer and discharge of rainwater runoff.

Therunoffdischarge systemforexcessiverainwaterisused totreat rainwaterrunoffthatexceedsthedesigncapacityof thestormsewer system.It isusually constructed througha comprehensiveselectionof naturalapproachesorartificialfacilitiessuchasnaturalwaterbodies, multifunctionalstoragewaterbodies，excessivestormwaterdrainage channels,storageponds,and deeptunnels..

Sponge City -- Project Background

Guangdong Lesso Environmental Corporate Management Co.,Ltd., with its subsidiary Guangzhou Environmental Protection Engineering Co., Ltd., is a comprehensive environmental protection service provider that integrates a full range of services including environmental protection consulting, environmental impact assessment, design, construction, operation, environmental monitoring, environmental supervision,and manufacturing of environmental protection equipment.The company holds a variety of professional qualifications, such as environmental engineering design, ecological construction and environmental engineering consulting, environmental supervision, environmental impact assessment, municipal engineering design, general contracting for municipal engineering, and professional contracting for environmental protection engineering.

In addition to providing customers with professional and dedicated designs and general contracting for the whole construction of sponge cities, the company can provide professional services for these following projects: municipal sewage and industrial wastewater treatment, governance of dirty and odorous water bodies, comprehensive improvement of rural environments, solid waste treatment,solid waste testing, soil remediation, urban water supply and drainage engineering, marine environmental protection, and other projects.

Applications and Solutions for Rainwater Management System

1. Buildings and Residential Communities

After organized confluence and transfer, and pretreatment such as pollutant interception, the rainwater runoff from building roofs, and the road surfaces of residential communities should be introduced into the LiD facilities in green spaces whose primary functions are rainwater infiltration, storage, and regulation. The typical process of a LiD rainwater system for buildings and residential communities is shown in the figure below:

Rainwater Utilization Process and Corresponding Product Series for Buildings and Residential Communities:

2. Urban Roads

The rainwater runoff from urban roads should be introduced into green spaces inside and outside boundarylines of roads through organized confluence and transfer, and pretreatment such as pollutant interception.And the runoff is then processed by the LiD facilities set up in green spaces whose primary functions are rainwater infitration, storage,and regulation.The typical process of a LID rainwatersystem for urban roads is shown in the figurebelow:

RainwaterUtilizationProcess and CorrespondingProductSeries for Urban Roads:

3. Urban Green Spaces and Squares

After organized confluence and transfer, and pretreatment such as pollutant interception, the rainfall runoff from urban green spaces, squares and their surrounding areas should be introduced into the LiD facilities in green spaces whose primary functions are rainwater infiltration, storage,and regulation.In this way, the rainwater runoff from itself and surrounding areas can be absorbed, and the waterlogging prevention and control capacity in the area can be improved by connecting to storm sewers and excessive rainwater runoff discharge systems in the area.The typical process of a LiDrainwater system for urbangreenspacesandsquaresisshown inthefigurebelow:

4. Urban Water Systems

Urban rainwater systems play an important role in urban drainage, waterlogging prevention,flood prevention,and the improvement of urban ecological environments, and are crucial links in the process of urban water circulation. The LID terminal regulation and storage facilities such as wet ponds and rainwater wetlands are also important parts of urban water systems, and urban water systems are also significant parts of the excessive rainwater runoff discharge system.The typical process of a rainwater system of the urban water system is shown in the figure below:

Corresponding Product Series for Urban Water Systems in a Sponge City System:

Rainwater Management System Products

(l) Pipeline System

1. Building Drainage Series 1.1 Siphonic Roof Rainwater Drainage System

The siphonic roof rainwater drainage system is primarily composed of siphonic roof outlets, high-density polyethylene (HDPE) pipes, and related accessories, and is applicable for rainwater drainage on various roofs, including concrete and steel structures. Compared with traditional gravity drainage systems, the siphonic roof rainwater drainage system offers these following advantages: flexible arrangement of roof outlets,horizontal pipes with no slope,fewer rainwater risers, decreased on-siteconstructionworkload,and spacesavings.

1. Building Drainage Series 1.2 PVC-U Drain Pipe System

2. Buried Drain Pipe Series

2.1 HDPESpiral Enhanced Hollow-wallPipe

TheHDPE spiral enhanced hollow-wall pipe isproduced by usinghigh-density polyethylene(HDPE）as the raw material,and molded by hot extrusion,and winding.The inner and outer surfaces of thepipesare smooth; thepipe wall is designedintoanI-shapedstructurethatconformstomechanical requirements，providing good ring stiffness.Additionally，the outstanding toughnessofHDPEmaterialusedgivestheproductexcellentflexibility. Therefore,the product iswidely used.The specificationrange of HDPE spiral enhanced hollow-wall pipes is DN200 to DN2400,with the ring stiffness grades of SN4,SN8,and SN12.5.

2.2 HDPEDouble-wall CorrugatedPipe

TheHDPE double-wallcorrugated pipe is produced by using high-density polyethylene(HDPE)as therawmaterialand a co-extrusionprocessforboth innerandouterlayers，combinedwithvacuumandgas-assistedinjection molding techniques.Thepipe has these followingadvantages:highring stiffness，good flexibility，abrasion resistance，pressure resistance,impact resistance，smooth inner walls,low fluid friction resistance，corrosion resistance,light weight,easy transportation，simplified installation,and long service life.The specificationrange of HDPE double-wall corrugated pipes is DN225 to DN800,with the ring stiffness grades of SN4, and SN8.

2.3 Metal Reinforced PE Spiral Corrugated Pipe

Themetal reinforcedPE spiral corrugated pipeis akind of structured wall pipe that is windingly molded through the melt compounding of PE and steel strips. The pipe is composed of a three-layer structure.The HDPE pipe is used as the pipe body;The high-strength steel strip shaped by spiral winding is used as the reinforcement;A pre-coated specialresin on the surface of thesteelstrip is usedasthecoveringlayerofsteelandplastictoenhancetheadhesion betweenthesteel stripand thepolyethylene.Allpolyethylenerawmaterialsare fully melted for winding molding.These designs above result in the pipes that combinetheflexibilityofplasticpipeswithimproved_pressure-bearing performance.ThespecificationrangeofmetalreinforcedPEspiralcorrugated pipes is DN300 to DN2400, with the ring stiffness grades of SN8, SN12.5, and SN16.

2.4 HDPE Spiral Enhanced Structured-wall Pipe (TypeB)

The HDPE spiral enhanced structured-wallpipe(Type B)(commonlyknown as softmanagement set)is a circular hollowspiral ribbedflexiblepipe that is made of the high-densitypolyethylene(HDPE)resin as the raw material and supported by thepolypropylene(PP)corrugated pipe through a hotwinding molding process.The pipe has thesefollowing advantages: smooth inner walls, high ring stiffness，good toughness, corrosion resistance, and impact resistance,which can ensure thereliable operationof the drainage system under different operating conditions.The specificationrange of HDPE spiral enhanced structured-wall pipes (Type B) is DN200 to DN1700,with the ring stiffness gradesofSN4,SN8,SN12.5,and SN16.

2.5 PVC-U Double-wall Corrugated Pipe

The PvC-U double-wall corrugated pipe,formed after the process of airinjectionmolding,ismade of hardpolyvinylchloride(PvC-U)as theraw material through a two-layerextrusion toforminner and outerlayers.Thepipe has these following advantages: high ring stiffness, smooth inner walls, good connectionsealing,resistance to acid,alkaliand salt,light weight,largelength, fewerjoints,easy connection,quick construction,strong wearresistance,and long service life.Thespecificationrange ofPvC-Udouble-wallcorrugated pipes is DN63 to DN1000,with the ring stiffnesS grades of SN4,and SN8.

Plastic Inspection Chamber

Plastic inspection chambers can be divided into inspection chambers for drainage of buildings and residential communities, and inspection chambers for municipal drainagebased on their applicationscope.Specificaly,The plastic inspection chambers for drainage of buildingsandresidential communities consistof a chamber body，raiser,coverframe，and chamber cover，while thoseformunicipaldrainage are composedofa chamberbody，raiser, convergent circle,cover frame, and chamber cover.The chamber body,a key component of the plastic inspection chamber, is molded in one-step injection technology and has excellent integrity. The chamber body is flexibly connected with the raiser and the branch pipe through the sealing ring, which facilitates quickandeasyoperationandprovidesgoodsealingperfomance.

LESSO plastic inspection chambers are configured with full specifications and a raiser diameter range of DN200 to DN1200 mm. Meanwhile,the specificationrange for branch pipes of the inside-diameter series is from 150A to10ooA, and the specification range for branchpipesof theoutside-diameterseriesisfrom110Bto50oB.

(lll) Rainwater Harvesting and Reuse System

1. Rainwater Storage Modules

The rainwater reservoir is assembled from rainwater storage modules that are made of polypropylene raw material with injection molding technology. These modules are resistant to acid and alkali corrosion, anti-aging, odorless, and antibacterial, and have a long service life.The modules can be combined in any way to adapt to different excavation structures, and the combined modular rainwater reservoir has a high resistance to vertical loads,

with theporosityranging from 93% to 97% Theassembly of the modules is fast and simple. The modules can perform various functions such as collection, reuse, regulation, storage, discharge and infitration,depending on the different design requirements and constructionprocesses.

LESSOhasdeveloped Type|and TypeIl water storage modules for different applications.

3. Removal Well Series

The removal well is used to discharge the initial rainwater with a runoff thickness of 2 to 3\mm. Since the initial rainwater has a higher concentration of pollutants, the removal rainwater can be discharged into the sewage pipe network and then collected at the sewage treatment plant for purification. The removal well is divided into a simple removal well and a mechanical removal well. The simple removal well has a simple structure, and provides less precise control over the runoff thickness. During the initial stage of the rainfall the cover plate in the mechanical removal well is automatically opened due to the action of gravity so that the initial rainwater runoff is directly discharged through removal outlets after entering the chamber. When the rainfall increases and the water level rises, the cover plate is automatically closed under the action of a floating ball to stop the removal,thus ensuring the function of initil rainwater removal.

The truncated basket chamber is used for the filtration of initial rainwater. It is equipped with a built-in stainless steel truncated basket that can intercept larger trash and leaves. The basket is equipped with a handle to facilitate cleaning out any filtered waste in the basket during maintenance.Meanwhile, the truncated basket chamber is designed with a built-in silt setting pit to precipitate the sludge and fine sand carried by the rainwater for convenient removing of sludge during maintenance, thus reducing the operating load of subsequent pretreatment facilities.

4. Truncated Basket Chamber Series

5. Automatic Filter Well

The automatic filter well is designed with a special inclination angle and a filter unit. After the rainwater is fitered by the filter screen, the impurities willautomatically fall into the impurity collection chamber along the screen surface,after which they are discharged through the sewage outlets to realize automatic distribution discharge.Withan accuracy of 1\:\:\mathsf{mm}, thefilterscreencaneffectivelyinterceptparticles largerthan 1\mm suchasgravel,ensuring excellent treatment results.

6. Trench Series

The trench is mainly made from polymer resin, and prefabricated in the factory. It features a linear water inlet method instead of the traditional step feed method of gutty inlets to reduce the length of the catchment slope. The main cross-section of the trench adopts a U-shaped structure so that there is a higher flow rate in the bottom of the trench, providing good self-purification. The product offers these following features: high compressive strength, good impact resistance, strong corrosion resistance, and long service life. It is applicable for the ground or side-wall drainage in areas such as public transport pavements, pedestrian areas, squares, and parks.

7. Buried All-in-one Machine

The buried allin-one machine is composed of systems such as circulating water pump, sand filter， six-position changeover valve， and intelligent control. It has six functions: filtration, circulation, disinfection, backwashing, bottom pollutant suction, and water surface cleaning. The machine is designed with the filtration and disinfection equipment for the deep treatment of rainwater,and can provide various disinfection measures such as ozone，ultraviolet sterilization, and automaticreagent feeding according tocustomer needs.

The UV steriization system combines mutiple disciplines including optics, microbiology, mechanics, electronics, and fluid mechanics. Since the product adopts a high-efficiency, high-intensity, and long-lasting UV light generation device, it can provide strong UV irradiation. When various bacteria, viruses and microorganisms in the water are subjected to a certain dose of UV radiation, the DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) in the cells are damaged, causing the microorganisms to die rapidly and ensuring thorough disinfection and purification.

The chamber of the sand filter is filled with filter sand. When the control knob is turned on, the rainwater in the rainwater reservoir is pumped into the fitration device by a water pump, after which any tiny contaminants in the rainwater are filtered out by the filter sand. The filtered clean water passes through the control switch at the bottom of the fiter and then returns to the clear water pool through the pipe.

10. Automatic Self-cleaning Filter

The automatic self-cleaning filter is composed of a motor reducer, filter housing, filter screen, combined scraping-brushing cleaning system, PLC controller and an electric drain valve. It is used to intercept solid impurities and particles in the water by means of filterscreentoreducewaterturbidityandimprovewaterquality.Whenthe contaminants on the filter screen reaches the set value, the system will automatically open the drain valve and the internal contamination removal mechanism to clean and discharge the impurities on the filter screen. The automatic self-cleaning filter can remove the impurities in water such as sediment, clay,rust, suspended matter, algae, biological mud, corrosion products,macromolecular bacteria，organics，and microscopic particles to achieve water purification.

Rainwater Harvesting and Reuse System RAINWATERHARVESTING ANDREUSESYSTEM

11.Geotextile

The geotextile is a permeable geosynthetic material made of synthetic fibers by needling or weaving technology.It provides these following excellent functions: filtration, drainage, isolation, reinforcement,seepage prevention,and protective property,and offers these following advantages: light weight, high tensile strength,good permeability,high-temperature resistance，frost resistance，aging resistance，and corrosion resistance.The specifications of thegeotextilerange from 100\ g/m2 to1000 g/m2.

12. HDPE Geomembrane

The HDPE geomembrane is a kind of polymer chemical flexible material with a plastic membrane as its impermeable substrate, and offers thesefollowing advantages:arelativelylow specific gravity，strong extensibility，high deformation adaptability, corrosionresistance,low-temperatureresistance,and good frost resistance.

It is used to seal the water reservoir in the rainwater harvesting andreusesystem.

13. Rainwater Control Cabinet

Therainwater controlcabinet adopts PLC programming to facilitate system controlfor rainwater harvesting,and display the liquid levels in each reservoir and the operating status of motors in real time, enabling the system to operate efficiently both during periods of adequaterainwater and waterscarcity, and realizing a more energy-efficient and scientific operation of thewholerainwater system.

(IV) Rainwater Infiltration System

1. Infiltration Well Series

The raiser and bottom of an infiltration wellare perforated to allow for rainwater infiltration, with a percentageofopeningof 1% to 3%. It is applicable for applications in areas with smaller loads,such as pedestrians,squares,and greenspaces.

(IV) Rainwater Infiltration System

2. Infiltration Pipe Series

The infitration pipe is produced by using specialized equipment to drill multiple rows of circular permeable holes around the circumference of the pipe. Different permeation requirements will be met by controlling thepercentageofopening.

LESSO

CHINALESSOGROUPHOLDINGSLIMITED

Lesso Group (Stock Code: 2128.HK)