Pengaruh nilai potensial redoks terhadap produksi biogas dari limbah rumah potong hewan

JATI, Bumiarto Nugroho, Ir. Imam Prasetyo, M.Eng.,Ph.D

2007 | Tesis | S2 Teknik Kimia

Penelitian ini mempelajari tentang pengaruh nilai potensial redoks terhadap produksi biogas dari limbah Rumah Potong Hewan (RPH) dan pengaruh adanya darah terhadap produksi gas metana yang dihasilkan selama proses biogas berlangsung. Penelitian mengenai pengaruh potensial redoks terhadap produksi biogas dari limbah RPH dilakukan dengan tiga perlakuan. Pada perlakuan I, subtrat yang digunakan berupa limbah RPH yang terdiri dari isi perut (rumen, omasum, usus), feses, urine dan darah. Substrat dicampur dengan air dengan rasio massa limbah RPH : Air adalah 100:0, 67:33, 50:50 dan 33:67. Pada perlakuan II, substrat yang digunakan sama dengan perlakuan I, tetapi disertakan darah limbah RPH pada perlakuan ini. Sedangkan, komposisi substrat pada perlakuan III yang digunakan adalah komposisi pada perlakuan II yang menghasilkan kadar gas metana paling optimal, dan dilakukan variasi nilai potensial redoks yaitu -240 mV, -260 mV, - 280 mV, dan -300 mV dengan menambahkan batu kapur. Proses pembuatan biogas substrat-substrat tersebut berlangsung selama 2 minggu dalam kondisi anaerob. Hasil penelitian diperoleh bahwa kadar gas metana paling optimal pada pelakuan I yaitu sebesar 30,2 % dihasilkan oleh sampel dengan rasio massa limbah RPH : air = 50:50 dan volume optimal yaitu 324,49 mL dihasilkan oleh sampel dengan rasio massa limbah RPH : air = 67:33. Adanya darah pada perlakuan I dapat menghambat produksi biogas, karena dengan adanya darah dapat menyebabkan nilai potensial redoks substrat kurang negatif. Sedangkan pada perlakuan II, kadar gas metana dan volume optimal yaitu sebesar 50,1 % dan 373,37 mL yang dihasilkan oleh sampel dengan rasio massa limbah RPH : air = 50:50 dengan nilai potensial redoks – 225 mV. Pada perlakuan III adanya penambahan batu kapur untuk merubah nilai potensial redoks menjadi semakin negatif dapat meningkatkan produksi biogas. Penambahan batu kapur yang terlalu banyak justru akan menghambat produksi biogas, karena nilai pH awal yang terbentuk dapat melewati batas persyaratan pembentukan biogas yaitu 8. Kadar gas metana paling optimal yaitu sebesar 53,6 % dihasilkan oleh substrat dengan nilai potensial redoks awal -260 mV dan volume biogas optimal dihasilkan oleh substrat dengan nilai potensial redoks awal -280 mV.

The aims of this research are to learn about the influence of redoxpotensial to biogas production from abattoir waste and to know the influence of the existence of blood in the waste to methane production during biogas production process. The research of biogas process was conducted with three type of substrates at the digester. At the first treatment, substrate was abattoir waste that was consisted of rumen, faeces, urine and blood. The substrate was mixed with water, with the mass ratio of abattoir waste and water were 100:0, 67:33, 50:50 and 33:67. At the second treatment, the mass ratio of subtrate was same as with the first treatment, but at this treatment, the blood of abattoir waste was excluded in substrate. For the third treatment, the feedstock was the substrate that yielded the optimal methane production at the second treatment. At this treatment, limestone was added to the substrate to get the variations of redox-potential value. The variation of redox-potential value of substrate were -240 mV, -260 mV, -280 mV and -300 mV. All of the biogas process treatment was conducted during two weeks at anaerobic condition. Result indicated that the most optimal mole fraction of methane was 30.2 % that was yielded by subtrate with the ratio of mass of abattoir waste and water was 50:50 and the optimal volume was 324.49 mL from substrate with the ratio of mass of abattoir waste and water was 67:33. Existence of blood in the substrate at the first treatment can hamper biogas production, because blood can make redoxpotential value of substrate be positive. At the second treatment, the optimal methane production was 50.1 % for mole fraction and 373.37 mL for biogas volume. It was obtained from substrate with mass ratio of abattoir waste and water is 50:50 and the redox-potential value -225 mV. At the third treatment, limestone addition changed the redox-potential value to become progressively negative. It increased biogas production. The optimal mole fraction of methane at this treatment was 53.6 % and it was obtained from substrate with the redoxpotential value -260 mV. The optimal biogas volume at the third treatment was yielded from substrate with the redox-potential value -280 mV.

Kata Kunci : Limbah Rumah Potong Hewan,Produksi Biogas,Nilai Potensial Redoks, biogas, redox-potensial, abttoir waste, blood