5+sewage+systems船用生活污水处理系统

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1、TheHazardsandregulationsregardingtheSewageSystemsRawsewagedischargedintorestrictedwaterswilleventuallyoverwhelmtheselfpurificationabilityofthelimitedquantityofwater.InacloseddocktheeffectcanbeseeninablacksludgywaterwhichwhendisturbedgivesoffanunpleasantsmellpossiblyHydrogenSulphide.Whenthequ

2、antityofsludgeisreasonableaerobicbacteriadigestthesewagebreakingitdowntosimplecompoundsandCarbondioxideusingupOxygenintheprocess.ThesecompoundsandCarbondioxidepromoteplantlifewhichreturnsoxygentothewater.WhenthequantityofOxygenbecomessodepletedthattheaerobicbacteriacannolongerfunction,anaero

3、bicorbacterianotrequiringOxygentofunctionwilltakeover.Thebreakdownofthesludgeisthenassociatedwiththesameprocessofdecaywithfoulsmellinganddangerousgassesbeingproduced.Thereforetheprincipalmeansofsludgeconditioningonboardisthatofaerobicaction,TypesofsewagedisposalTherearefourmaintypesofsewaged

4、isposalsystemsfittedtoships;a.Dischargefromthetoiletbowlintoacommondrainleadingtooverboardviastormvalvesb.Asaboveexceptcommondrainleadstoastoragetankwithorwithoutaeration.Contentsdischargedashoreoratseawhenappropriate.c.Sewagetreatmentsystemswithsewagebeingcollectedandtreatedtoproduceanefflu

5、entsuitabletodischargewithouteffectonenvironment.d.Vacuumcollectingsystemwherethedrainsarekeptataslightlynegativeabsolutepressure,onflushingwater,sewageandairaredrawnintothedrainsbeingledtoacollectingortreatmenttankwhichiskeptatatmosphericpressure.AerobicandanaerobicbacterialactionWhenthesew

6、ageentersthedrainagesystemitisacteduponbyaerobicbacteriaandisbrokendown,duringthisprocessthenaturallyoccurringAerobicBacteriastripthewaterofoxygenandproduce;morewater,CarbonDioxide,andmorebacteria.If,however,thereisinsufficientoxygenforthesebacteriathenalternativebacteriadominates.TheseAnaer

7、obicBacteriaproduceHydrogenSulphide,MethaneandAmmonia.Thesegassesareeitherhighlytoxicorflammableorboth.InparticularHydrogenSulphideistoxictohumansinconcentrationsdownto10ppmanditsflammablevapoursareheavierthanairsomaybuildupinlethalpocketsinenclose