Pemanfaatan limbah Tulang Ikan Kakap Merah (Lutjanus sp.) untuk meningkatkan kadar fosfor dalam kompos
P ada proses pengolahan fillet kakap merah (Lutjanus sp.) bagian tulang dengan proporsi mencapai 13,70% dari keseluruhan tubuh ikan belum banyak dimanfaatkan (Peranginangin et al., 2005). Menurut Statistik Perikanan Tangkap Indonesia (2015), hasil tangkapan ikan kakap merah menyumbang volume terbesar, yaitu sebanyak 130.301 ton/tahun, maka diperkirakan potensi limbah tulang ikan kakap yang dihasilkan dapat mencapai 17.851,23 ton/tahun. Kandungan mineral yang tinggi di dalam tulang terutama fosfor (P) memiliki potensi untuk dimanfaatkan sebagai bahan peningkat kadar P kompos sehingga dapat memenuhi syarat standar baku mutu kompos yang ditentukan dalam SNI 19-7030-2004. Kadar hara yang diperoleh dalam tepung tulang ikan (TTI) adalah ; C (3,35%), N (0,48%), P (30,90%) dan K (0,02%). Efek dari TTI terhadap kenaikan kadar P dalam kompos telah diketahui. Rata-rata sampel kompos B, C, D serta E mengalami kenaikan kadar P sebesar 428,57; 542,85; 657,14 dan 914,28% terhadap rata-rata kompos A (blanko). Penambahan TTI yang ideal ditunjukkan oleh kompos B dan B’ yaitu sebanyak 15 gr, dengan kadar P sebesar 0,37% dan telah memenuhi syarat SNI 19-7030-2004, yaitu 0,10%. Rasio C/N menurun selama 21 hari periode pengomposan,dengan penurunan yang paling besar adalah kompos C, D, E dan E’ dengan rasio16:1. Kadar kalium (K) tertinggi tercatat pada kompos sebesar 0,13%, nilai ini masih di bawah kadar minimum K yang dianjurkan, yaitu 0,20%. Kadar N tertinggi tercatat masing-masing pada kompos A’, B’, C, C’ dan D sebesar 1,09% serta kadar N terendah tercatat pada kompos A sebesar 1,06%. Kadar N pada sepuluh sampel kompos telah memenuhi syarat minimum N pada SNI yaitu sebesar 0,40%. Kadar C tertinggi tercatat pada kompos B (21,02%) dan terendah pada kompos D (17,21%). Nilai C tertinggi dan terendah pada kompos telah memenuhi kadar C minimum sebesar 9,80%. Pengomposan dilakukan di dalam ember yang sudah dimodifikasi sebagai komposter aerobik (dengan lubang udara), Pengadukan tumpukan kompos untuk setiap sampel dikontrol sebanyak 2 hari sekali. Periode mesophilic (23-450C) terjadi selama 21 hari periode pengomposan.
I n the processing of red snapper fillet (Lutjanus sp.) part of the bone with the proportion reached 13,70% of the whole body of fish, and has not been exploited (Peranginangin et al., 2005). According to Indonesian Fishing Statistics (2015), red snapper catches accounted for the largest volume, as many as 130.301 ton/year, the estimated potential bone waste generated from red snapper can reach 17851,23 ton/year. High mineral content in the bones, especially phosphorus (P) has the potential to be used as compost enhancer material so that it can qualify compost quality standards specified in SNI 19-7030-2004. Nutrient levels were obtained in fish bone meal (FBM) is ; C (3,35%), N (0,48%), P (30,90%) and K (0,02%). Effects of fish bone meal (FBM) to the rising levels of phosphorus (P) in the compost has been known. Phosphorus levels of average compost B, C, D, and E increased at 428,57; 542,85; 657,14 and 914,28% against the average compost A (blank). FBM ideal addition indicated in compost B and B' is as much as 15 grams, with a P content of 0,37% and has been passed according SNI 19-7030-2004 of Compost Quality Standards (0,10% for P concentration ratio). C/N ratio decreased over the 21 days period of composting, with the greatest decline was compost C, D, E and E' with a ratio of 16:1. Levels of potassium (K) is the highest recorded in the compost is 0,13% which is still below the minimum levels of recommended K, i.e.0,20%. Levels of nitrogen (N), the highest recorded respectively in compost A', B', C, C' and D with value of 1,09% and the lowest of recorded N content was compost A; 1,06%. N content in ten samples of compost were eligible minimum N on SNI i.e. 0,40%. Levels of Carbon (C) is the highest recorded in compost B; 21,02% and the lowest in the compost D; 17,21%. Both of C value (max & min) on the compost has met the minimum C content of 9,80%. Composting is done in a bucket that has been modified as a aerobic composter (with air holes), turning the compost pile for each sample is controlled as much as once/2 days. Mesophilic period (23-450C) occurs during the 21-day period of composting.