I\lak/fax SILT PROTECTOR PREVENT DIFFUSION OF SILT IN WATER TAIYO KOGYO CORPORATION

I\lak/fax SILT PROTECTOR PREVENT DIFFUSION OF SILT IN WATER TAIYO KOGYO CORPORATION

Iribules Projects odama.ging E 'ronmenl efunction of Silt Protector Silt Protector is a flexible membrane product that has been designed to physically prevent diffusion of pollution generated in dredging or reclamation works on the seas or riverso The pollution (fine particles) is said to badly affect the benthic organisms (marine life that live in the bottom) including making the breathing of fishes dihicult and reducing underwater illuminanceo The Silt Protector prevents diffusion of pollution safely because it uses a physical means without using chemicals that will be the cause of the secondary pollutiono The Silt Protector basically consists of the curtain section that is made of synthetic textile (mainly polyester), the float that hangs the curtain in the water, and the mooring section for hing the unit at a specified locationo

Models and Features The Silt Protector consists of several types that are individually subdivided into some ranks so that the user is able to select units best suited to specific site conditions and work items. The Silt Protector con be used individually or separately, or by combining the units. efixed Hanging Type Silt Protector This type is used the most frequently. It basically consists of floats on the surface and curtain and weight chain below the surface. One span of this product is 20m long. It is moored to the bottom through anchor ropes and anchors at every 19.5m point. The anchor ropes are steel wire type or synthetic fiber type, and anchors are concrete blocks, usually. when this product is used under high wave conditions, the curtain with the verticallength of lom or less is used and standing type is used together in many cases. wh en wave is low, the curtain of 20m long or more may be used. The fixed hanging type Silt Protector is classified into four ranks, A, B, C and D so that a type best suited to a specific application con be identified. 3

.General site condition for hanging fixed type Rank Suitable site conditions Float dia (mm) Standerd specifications Float type Curtain material (hain weight (kg/m) A Area outside of breakwater.wave height: 1.Sm or less 600 Unspaced spo- # 800 or 500 10.Velocity of current : O.Sm/ sec or less Wide area inside of breakwater, or inside of inlet that is B sheltered by the natural submarine topography.wave height : 1.0m or less +Velocity of current : 0.2m/sec or less 400 Unspaced spo- #500 or 300 S ( Area with medium extent inside of breakwater.wave height : 0.8m or less.velocity of current : 0.1 m/ sec or less 300 Unspaced spo- #500 or # 300 S D Lakes, or weil sheltered area as colm as lakes.wave height : O.Sm or less.velocity of current : O.OSm/sec or less 300 Spaced spo- # 300 3 Remarks *Standard unit length is 20m. *Anchor is not included in the unit. EFFECT Silt Protedor generally provides the following effeds on prevention of diffusion of pollution in the sea. Acceleration of settlement of silt by interference of particles Installotion of the Silt Protedor suppresses diffusion of the pollution and Without Silt Protector Distance trom source make the soil particles interfere with each other to accelerate their settlement. No Silt Protector ].Reduction of distance required to settle the silt Installotion of the Silt Protedor as shown narrows the settlement range, resulting in minimizing the diffusion of pollution after the unit. With Silt Protector 4

More Types.Frame type Silt Protector This type hos been designed to en close loco 1 pollution caused by the grab dredging. It consists of floats (usually discharge pipes are used), curtain and ballast at the bottom. Mid-ballast may be added as necessary. Many of this type is made so that the length of the curtain con be changed according to the depth by using an winch and wire rape. The length of the curtain is made less than 15m for eosier used on the grab dredger. -Direction of Flow.Combined installation Frame type Silt Protector is, in many cases, installed together with hanging type to avoid turbid water when r 820m... Hanging Type dredger moves, tucking up curtain. For deep sea like 20m water depth, combined installotion of hanging type Grab Dredger Frame Type =m 460m and standing type is sometimes used. In case, boot passing is necessary, sinkable hanging type is used for open /Standing Type /Sinkable Type J part. 5

.Standing Type Silt Protector The standing type Silt Protector hos been developed to prevent diffusion of pollution that may occur near the bottom in dredging or dumping of soil. This type consists of an anchor{normally steel H beam is used), curtain and float that pulls up the curtain with its buoyancy. The diameter of generally used float is 300mm(spaced type), and one span of this type is 20m long. In many cases, this type is used together with the hanging type product. Sinkable Hanging Type Silt Protector The sinkable hanging type Silt Protector is used when it is necessary to make an entrance/ exit for the passage of vessels that enter into or exit from the reclamation area. The fundamental construction of the sinkable hanging type Silt Protector is similor to the fixed hanging type Silt Protector except that the float is inflatable. The float is hollow and is made of synthetic rubber. When making this unit afloat on the water, the float is inflated by charging it with air, that con be completed in a very short time. The unit con be sunk immediately by deflating the float. The typical case of application of the Silt Protector is the reclamation of artificial island. G

Application _10m X 4100 78.6 15 10 78 5 I 300m 6 50 80= 60 50-46.3 65.1 80 12 15 20.2 14.3 34.6 43.6 41.0 37.6 25.8 13.8 29.1 16.6 75.5 35.1 36.4 18.1 14.1 80 70-1580.8 Pollution Cross 12 Removal Section 70 12 X = 76.0 81.3 41.0 Rate (%) 41.0-14.3 I 60 - r_2ml~l~ 36.4 14.1 X100=61.3 50.7 37.6 ppm - 20.2 37.6 XeMide layer layer = 48.4 35.1-18.1 lef! right side sideeupper layer, right side 1~1100ml I Offshore dumping I 12m I 12mJ~1 IÁ :: T eupper layer, lef! side 120m 172 9 172-9 172 X 100 = 94.8 T uroulence caused by dumping trom barges 200 U 37 ppm 200-37 200 X100=81.8 Pollution removal rates shown in the above table are data taken from actual sites. 7

( 1.e~illlll[.lj[.]I~r::r.Ir-TiI eexamination Flow It is recommended to follow the flow described here to make the planning of installotion of Silt Protector. llt}f:lm[.jo.~1jlll[.ii~rnn~r::r.ir.tii J ~ lrnt'ej~~ J Design conditions External force estructural Analysis *Wind velocity *Current velocity *Wave height *Wave period *Wave length *Bottom soil * Period of use *Water depth * Tidal range The design extern ol force, W, applied to the Silt Protector is divided into the following three types of horizontol pressures. Pressure!rom Aow Wl Pressure!rom wove W2 Pressure!rom wind W3 The specifications for the Silt Protector to be used are determined based on the externol conditions of the site such os wind speed, current speed, wave height and depth of water by using 0 specified structurol calculation. Estimate conditions Typical diffusion of pollution * Area of work *Work item * Dredging rote *Working hours *Operotion period * Soi! dato * Target value of SS *Current velocity *Water depth ~I. Souree of Pollution Downstream Direction edihusion Estimate Taiyo Kogyo Corporotion theoretically estimates the diffusion of pollution in case no Silt Protector is used, and effect of Silt Protector. 8 Examination

Installation elnstallation works for Fixed Hanging Type Silt Protector Preparation * Preparation of working yard *Making anehor bloeks * Bring materials to the site Assembling on the land * Inspection * Series eonnection of spans *Temporary tueking up of eurtains Installation works on the sea * Loading on the barge *Towi ng barge * Plaeing anehor bloeks * Installing Silt Protertor r 1.,'/ ~ " I 1 "q,/ / i, /,~ I 9

- Specifications for the curtain material SPO-#800 I Tensile strengh I 800kgf/3cm I ematerial for curtain and float components The curtain and inner cover for the float are made of high strength polyester synthetic fiber that hos been studied and developed to give excellent durability, cold-resistance, chemical resistance and light resistance. SPO-#500 [T ensile str~!ni!hi 500kgf!3cm~ ~...,~-.- J The float cover{outermost cover) is made of high strength polyester tarpaulin with superior UV (ultra violet ray)resistance in addition to the features of the polyester synthetic fiber. The float is made of solid cylindrical SPO-#300 f T~~silestr~ngh I 300kgf!~c~1 t III L.. rr _ - I.J styrene foam with high weather resistance. Since the material will not absorb water, the buoyancy of the float is not reduced. The float adapts to the wave weil thanks to the advantage of the materia!. f I II I :~ j L ~ 10 Material

.a~ (EUROPE) B.v. Middelblok +3118237 164, 2837 327 Tel. + 31 182377 329 ~EOPEX ~~~~~~,~~30 ~ ~~ugg~~~á~~ (NL) Fax "I europe@geo pex. com E-mal Internet www.geopex. com T AIYO KOGYO CORPORA TION Singapore Representative Office No.1, Science Center Road The Enterprise #09-60,Singapore 609077 Tel: +65-6822-6293 Fax: +65-6822-6294 Email: EM002923@MB.taiyokogyo.coJp Website : http://www.taiyokogyo.co.jp/sipro/frames/fdefault.htm Tokyo Office 2-33-16,lkejiri,Setagaya-ku,TOKYO 154-000 1,JAPAN Tel: +81-33714-3366 Fax: +81-33791-5454 Email: NI000263@MB.taiyokogyo.co.jp Website : http://www.taiyokogyo.co.jp No.2004-400-0023 2004.4.2000 I\Iakl/ax