Judul: Pengaruh nutrien dan pH reaktor anaerobik laju tinggi untuk penanganan limbah cair yang mengandung melanoidin
Abstrak: Melanoidin adalah senyawa kompleks yang terbentuk dari reaksi non enzimatiks Maillard antara gula dan asam amino. Kompleks melanodin inilah yang diperkirakan sebagai penghambat proses penanganan limbah cair sehingga sulit dihasilkan kualitas efluen yang memenuhi baku mutu (antara lain COD maksimum 100 mg/L, BOD maksimum 50 mg/l). Penelitian yang dilakukan bertujuan untuk mendapatkan tingkat pH dan konsentrasi nutrien yang sesuai untuk bioreaktor anaerobik skala laboratorium pengolah limbah cair yang mengandung melanoidin. Nutrien dan pH merupakan dua parameter penting dalam pengoperasian bioreaktor, karena keduanya mempunyai pengaruh dominan dalam pembiayaan reaktor skala penuh. Bioreaktor yang digunakan adalah tipe Fludized Bed dengan volume total 5.6 liter, suhu operasi 35°C, pH dikontrol sekitar 7 secara manual. Percobaan tentang pengaruh nutrien dan pH dilakukan setelah reaktor mencapai steady state (3 bulan operasi), dengan tingkat removal COD sebesar 85 persen. Pada tingkat laju pembebanan organik volumetrik 26 Kg COD/m².hari, perubahan rasio bahan organik dari nutrien (TOC: N:P) dari 100 10 2 menjadi 100 5: 1 mempengaruhi beberapa parameter unjuk kerja reaktor secara signifikan. Nilai COD efluen meningkat dari 2 000 mg/liter menjadi 3 200 mg/liter dan diikuti dengan penurunan laju pembangkitan gas dari 30 liter/hari menjadi 22 liter/hari, tingkat dekolorisasi dari 25 persen menjadi 16 persen. Penurunan pH reaktor dari sekitar 7 menjadi 6.5 terbukti tidak terlalu efektif menurunkan kebutuhan alkali reaktor, sedangkan tingkat COD efluen meningkat dari 2 000 mg/liter menjadi 2 500 3 000 mg/liter. Produksi gas menurun dari 30 liter/hari menjadi 23 liter/hari. Dengan demikian, kondisi pH netral dan komposisi TOC: N: P influen sebesar 100: 10: 2 merupakan kondisi operasional yang lebih menguntungkan. ...
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Judul: Kajian proses denitrifikasi limbah organik dengan sistem modified ludzak-Ettinger : Studi kasus pada instalasi pengolahan air limbah IPAJ PT Capsugel Indonesia-Cibinong
Abstrak: Industrial wastewater effluents discharged that contains high nitrate concentration can cause eutrophication, poisoned to baby and child, and also toxic to water biota. High nitrate concentration in drinking water can cause Methemoglobinemia (blue babies). Nitrate-nitrogen yielded from ammonium- nitrogen oxidation through aerobic pond on WWTP. The case study at WWTP of PT. Capsugel Indonesia (PTC) was aimed to optimalize denitrification process in order to achieve the nitrate effluent quality as according to Baku Mutu I. This research was initiated by identification of WWTP process, analysing process influencing denitrification and followed by various process such as: an internal recycle treatment, SRT and HRT treatment at clarifier, jar test and determination of methanol dosing (as additional substrat) that influenced denitrification. All analytical procedures followed a Standard Operation Procedure (SOP) from WWTP PTC and based on HACH manual book and APHA 1992. Modified Ludzak-Ettinger (MLE) is a model which is most commonly used at WWTP because of its simply process. MLE represent nitrification- denitrification system in a single sludge activated-sludge for nitrogen removal which combine carbon removal, amonia oxidation and nitrate reductation in the same process. Shock loading and fluctuation of ammonium-nitrogen in the influent reduced WWTP performance. Initially, nitrate concentration level has been controled by adjusting the rate of mixed liquor recicling. Mixed liquor from aerobic pond to anoxic pond wes expected can bring nitrate as much as possible for oxidizing carbon source where nitrates replace oxygen in denitrification. Increasing of the mixed liquor recirculation rate really did not bring nitrate degradation level to the effluent. This happened because all COD as carbon source in anoxic pond have been used so that anoxic pond reached the maximum capacity for denitrification. Another possibility is that WWTP depend on carbon source only from waste influent. Carbon source from influent pertained a slowly biodegradable COD so denitrification rate also became slow. One of MLE system purpose is to reduce the cost of additional carbon sources, but in this case, the system was actually require external carbon sources. This research used technical methanol 2% (v/v) with dosing rate was 4 L/h combined with internal return rate (IR) = 4Q, the return activated sludge (RAS) rate IQ and influen rates (Q) = 1.2 m³/h gave acceptable results for nitrate-nitrogen removal. This combination reduced the average effluent nitrate concentration from 46.07 mg/L NO3-N to 12.6 mg/L NO3-N. This value below the regulation of Baku Mutu 1. The methanol addition in WWTP increased alkalinity formed during denitrification. It reduced up to 80% of Na2CO3 consumption.
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Judul: : Persamaan Tunggal sebagai Representasi Kurva Komposit
Abstrak: A mathematical method is introduced to represent a composite curve based on an extension of analytic geometry. The representation is given either with a single equation or with two equations, in the case of parametric representation. This method permits the representation of composite curves in similar manner to the conventional representation of non-composite curves. Some mathematical tools, including Heaviside unit step function and periodizer function, are used in the establishment of a single equation. In this paper, regular equations of regular and irregular polygon, as well as composite curves of two dimensions, are implemented using a computer algebraic system, Mathematica.
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