5+sewage+systems船用生活污水处理系统

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1、TheHazardsandregulationsregardingtheSewageSystemsRawsewagedischargedintorestrictedwaterswilleventuallyoverwhelmtheselfpurificationabilityofthelimitedquantityofwater.Inacloseddocktheeffectcanbeseeninablacksludgywaterwhichwhendisturbedgivesoffanunpleasantsmellp

2、ossiblyHydrogenSulphide.WhenthequantityofsludgeisreasonableaerobicbacteriadigestthesewagebreakingitdowntosimplecompoundsandCarbondioxideusingupOxygenintheprocess.ThesecompoundsandCarbondioxidepromoteplantlifewhichreturnsoxygentothewater.WhenthequantityofOxyge

3、nbecomessodepletedthattheaerobicbacteriacannolongerfunction,anaerobicorbacterianotrequiringOxygentofunctionwilltakeover.Thebreakdownofthesludgeisthenassociatedwiththesameprocessofdecaywithfoulsmellinganddangerousgassesbeingproduced.Thereforetheprincipalmeanso

4、fsludgeconditioningonboardisthatofaerobicaction,TypesofsewagedisposalTherearefourmaintypesofsewagedisposalsystemsfittedtoships;a.Dischargefromthetoiletbowlintoacommondrainleadingtooverboardviastormvalvesb.Asaboveexceptcommondrainleadstoastoragetankwithorwitho

5、utaeration.Contentsdischargedashoreoratseawhenappropriate.c.Sewagetreatmentsystemswithsewagebeingcollectedandtreatedtoproduceaneffluentsuitabletodischargewithouteffectonenvironment.d.Vacuumcollectingsystemwherethedrainsarekeptataslightlynegativeabsolutepressu

6、re,onflushingwater,sewageandairaredrawnintothedrainsbeingledtoacollectingortreatmenttankwhichiskeptatatmosphericpressure.AerobicandanaerobicbacterialactionWhenthesewageentersthedrainagesystemitisacteduponbyaerobicbacteriaandisbrokendown,duringthisprocessthena

7、turallyoccurringAerobicBacteriastripthewaterofoxygenandproduce;morewater,CarbonDioxide,andmorebacteria.If,however,thereisinsufficientoxygenforthesebacteriathenalternativebacteriadominates.TheseAnaerobicBacteriaproduceHydrogenSulphide,MethaneandAmmonia.Thesega

8、ssesareeitherhighlytoxicorflammableorboth.InparticularHydrogenSulphideistoxictohumansinconcentrationsdownto10ppmanditsflammablevapoursareheavierthanairsomaybuildupinlethalpocketsinenclose