Sigid Hariyadi DO BOD CODDept. Manajemen Sumberdaya Perairan - IPB

TINGKAT JENUH (SATURASI) OKSIGEN TERLARUT: Dissolved Oxygen (DO)

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Efek ketinggian (altitude) : ketinggian bertambah, tekanan parsial gas menurun, kelarutan gas berkurang ketinggian tingkat berkurangnya kelarutan 0 - 600 m4 % per 300 m 600 - 1500 m3 % per 300 m1500 - 3000 m2,5 % per 300 m

Efek temperatur : temperatur meningkat -- kelarutan berkurang

Efek salinitas : adanya berbagai mineral terlarut -- menurunkan kelarutan gas. tk. kejenuhan gas dalam air laut, 18 - 20 % lebih rendah daripada dalam akuades.

FAKTOR KELARUTAN / TINGKAT SATURASI OKSIGEN:

S %o = 0,030 + 1,805 Cl (%o)S (ppm) = 30 + 1,805 Cl (ppm)atauKandungan chloride (Cl) dihitung berdasarkan nilai salinitas :TINGKAT SATURASI O2 DI PERAIRAN LAUT

Dissolved Oxygen (DO) Oksigen adalah gas terlarut dalam air bila sampel terekspose ke udara DO bisa berkurang atau bertambah dari seharusnya pengambilan sampel utk titrasi perlu alat khususDISTRIBUSI VERTIKAL O2 dipengaruhi oleh: kondisi kelarutan hidrodinamika -- pergerakan air input fotosintesis penggunaan oleh biota & proses-proses kimiaBottle train samplerSigid Hariyadi 2005/2008

Prinsip penentuan DO (metode Winkler/Iodometri):endapan coklat bila tidak ada Oksigen:endapan putih proporsional dg jumlah O2 yang ada penambahan asamindikatorbirutak berwarnaSigid Hariyadi 2005/2008

Modifikasi metode Winkler/Iodometri:Flokulasi alum : 10% K2SO4Al2(SO4)3 & 35% NaOH bila air keruhSulfamic acid : NH2SO2OH bila kadar nitrit tinggiazide alsterberg : NaN3 bila kadar nitrit & bhn organik tinggiPomeroy Kirscman Alsterberg : penggunaan NaI (6 N) dan NaOH (10N) sbg pengganti NaOH + KI bila kadar oksigen lewat jenuh (over saturated)Sigid Hariyadi 2005/2008

Pengukuran dgn DO-meter:Warming up (on & biarkan bbrp menit)Kalibrasi alat pada angka nol (zero adjustment)Kalibrasi alat pada red line (red line adjusment)Kalibrasi alat thd kadar O2 udara pada temperatur dan tekanan udara (atau ketinggian tempat) Standardisasi dgn metode Winkler pd sampel yg sama (scr periodik)Prinsip Pengukuran:Tekanan O2dlm airSensor/membranarusJarum penunjuk skala/ digitalSigid Hariyadi 2005/2008

Botol BODSigid Hariyadi 2005/2008

probe DO-meter

BOD (Biochemical Oxygen Demand):(Biological)( DOi - DO5 ) mg/LInkubasi sampel dlm botol BOD pada 20oC selama 5 hari shg O2 terlarut pd hari ke-5 masih ada & terukurPerlu pengenceran yg cermat & aerasiBotol gelapInkubasi 20oC5 hariDO5DOiSigid Hariyadi 2005/2007

Bahan beracun: Hg, Cr6+, Cl2Kurangnya nutrienKurangnya mikroorganisme/bakteripH < 6 atau pH > 8Senyawa pengganggu:Sigid Hariyadi 2005/2007

Sigid Hariyadi 2005/2008

BOD decomposition rates vary widelyDO Consumed(mg/l)Decaying phytoplanton biomassBlack water organic matterMunicipal, industrial BOD loadsTime5 daysBOD5Sigid Hariyadi 2005/2008

BOD decomposition rates vary widelyTime50 days5 daysBlack water organic matterMunicipal, industrial BOD loadsDO Consumed(mg/l)Decaying phytoplanton biomassSigid Hariyadi 2005/2008

Sigid Hariyadi 2005/2008

Pre treatment:PenambahanNutrien &Pengenceran Sigid Hariyadi 2005/2008

BOD3 inkubasi pada 30 oC selama 3 hari upayakan nilai DO5(end) sekitar 1 mg/L sebaiknya selisih DO berkisar 5 7 mg/L mengubah pH, seluruh aktivitas ionik mengubah aktivitas organik mengubah salinitas lingkungan fisik-kimia- biologi air sampelPengenceran:Sigid Hariyadi 2005/2007(Tropik)

From: DHV Consultants BV & DELFT HYDRAULICS, 1999. Training module # WQ - 15Understanding biochemical oxygen demand test. Hydrology Project Technical Assistance. New Delhi

Bhn organik dioksidasi dg K2Cr2O7 pada kondisi asam & panas Kelebihan K2Cr2O7 dititrasi dg FAS (back titration) dg indikator feroinpotassium dichromateFerrous Ammonium Sulfate perlu larutan blanko senyawa pengganggu: Cl (air laut), NO2-sulfamic acid+ HgSO4 (200 mg/L per 1000 mg/L chloride)S %o = 0,030 + 1,805 Cl (%o)S (ppm) = 30 + 1,805 Cl (ppm)atauS= 30 %o = 30 000 ppm Cl = 16603,88 ppm 3,321 g HgSO4 perliter sampelContoh :Sigid Hariyadi 2005/2008

Reflux,untuk penentuan CODSigid Hariyadi 2005/2008

Wastewater typeBOD5 (mg/L)COD (mg/L)Tomato processing 450 - 1,600 650 - 2,300Corn processing1,600 - 4,7003,400 -10,100Cherry processing 660 - 1,9001,200 - 3,800Poultry plant processing 150 - 2,400 200 - 3,200Milk plant processing 940 - 4,7901,240 - 7,800

Becker, 2000. University of Maryland

rekreasi air budidaya ikan, ternak air baku minum irigasi pertanianSigid Hariyadi *

Perairan-peruntukanBOD (mg/L)COD (mg/L)Air tawar Kelas I210Air tawar Kelas II325Air tawar Kelas III650Air tawar Kelas IV12100Air laut - Biota20-Air laut - Wisata10-Air laut - Pelabuhan--

COD menggambarkan jumlah bahan organik total, baik yang mudah urai maupun yang sulit uraiBerdasarkan prinsip analisisnya, maka dapat dikatakan bahwa:BOD menggambarkan bahan organik mudah uraiNilai permanganat (TOM-total organic matter) TIDAK pernah lebih besar daripada nilai COD, karena oksidator yang digunakan pada analisis COD lebih kuat TVS (total volatile solids) juga menggambarkan bahan organik berdasarkan prinsip analisis pembakaran residu organik sampel pada suhu tinggi (550oC) dan gravimetriParameter bahan organik lainnya adalah TOC (total organic carbon)Sigid Hariyadi *

rasio antara bahan organik mudah urai dgnbahan organik total/sulit uraiCOD BODCOD TOMTotal Organic Matteroxidator: KMnO4CODBODTOMSigid Hariyadi *

Total Carbon (TC) all the carbon in the sample, including both inorganic and organic carbonTotal Inorganic Carbon (TIC) often referred to as inorganic carbon (IC), carbonate, bicarbonate, and dissolved carbon dioxide (CO2); a material derived from non-living sources.Total Organic Carbon (TOC) material derived from decaying vegetation, bacterial growth, and metabolic activities of living organisms or chemicals.Non-Purgeable Organic Carbon (NPOC) commonly referred to as TOC; organic carbon remaining in an acidified sample after purging the sample with gas.Purgeable (volatile) Organic Carbon (POC) organic carbon that has been removed from a neutral , or acidified sample by purging with an inert gas. These are the same compounds referred to as Volatile Organic Compounds (VOC) and usually determined by Purge and Trap Gas Chromatography.Dissolved Organic Carbon (DOC) organic carbon remaining in a sample after filtering the sample, typically using a 0.45 micrometer filter.Suspended Organic Carbon also called particulate organic carbon (PtOC); the carbon in particulate form that is too large to pass through a filter.TOC:

AcidificationOxidationDetection and QuantificationAnalysis of TOC:Acidification :The removal and venting of IC and POC gases from the liquid sample by acidification and sparging occurs in the following manner.Oxidation :The second stage is the oxidation of the carbon in the remaining sample in the form of carbon dioxide (CO2) and other gases. Modern TOC analyzers perform this oxidation step by several processes:High Temperature CombustionHigh temperature catalytic (HTCO) oxidationPhoto-oxidation aloneThermo-chemical oxidationPhoto-chemical oxidationElectrolytic OxidationHigh temperature combustion:Prepared samples are combusted at 1,350o C in an oxygen-rich atmosphere. All carbon present converts to carbon dioxide, flows through scrubber tubes to remove interferences such as chlorine gas, and water vapor, and the carbon dioxide is measured either by absorption into a strong base then weighed, or using an Infrared Detector.[3] Most modern analyzers use non-dispersive infrared (NDIR) for detection of the carbon dioxide.Detection and quantification:Accurate detection and quantification are the most vital components of the TOC analysis process. Conductivity and non-dispersive infrared (NDIR) are the two common detection methods used in modern TOC analyzers.TOC:

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