Coconut shell contains several components of biomass including cellulose, lignin, and pentosan, which can be used in the form of charcoal as a bioabsorbent. Sludge waste is a residue formed as a by-product of wastewater treatment at a wastewater treatment plant (WWTP). which emits odors that can disturb local residents. This study aimed to deodorize ice cream slurry waste using coconut shell charcoal and activated carbon as the odor adsorbent. The ratio of each adsorbent and ice cream waste was based on the preliminary experiment, namely 1:1, 1:3, 1:5, 1:6, and 1:7. The measurement parameters for the sludge were odor value, pH, temperature, and water content which were measured daily. Ammonia and sulfide levels were measured using the titration method, while protein levels were determined using a UV-Vis spectrophotometer. Odor reduction in sludge waste mixed with activated carbon as the adsorbent was better than that with coconut shell charcoal; by which the optimum mass ratio was 1:3 with a decrease of 97.13% that was obtained within seven days. The ammonia levels in the sludge waste decreased from 10,276 mg/kg to 308 mg/kg by the use of coconut shell charcoal with a mass ratio of 1:1 and to 252 mg/kg by the use of activated carbon with a mass ratio of 1:1 at the end of the experiment. The sulfide content in the sludge waste decreased from 1.215 mg/L to 0.0483 mg/L in the sample with coconut shell charcoal as an adsorbent with a mass ratio of 1:1 and to 0.0483 mg/L in samples with activated carbon adsorbent ratio of 1:1 at the end of the experiment.

Sebuah penelitian skala laboratorium dilakukan untuk menentukan pengaruh inokulum Azotobacter sp.terhadap pertumbuhan tanaman Sorghum bicolor yang akan diterapkan dalam usaha fitoremediasi lahanmarginal yang kurang sumber air. Unit percobaan perlakuan inokulum Azotobacter sp., urea, atau kontrolnegatif dibuat dengan cara menginokulasi sebanyak 1 mL masing-masing ke dalam pot berisi 2 kg tanahyang dibenami benih S. bicolor. Setiap pot kemudian dilabeli dengan tanda “Az” untuk perlakuanAzotobacter sp, “U” untuk perlakuan urea, dan “K” untuk kontrol negatif yang tidak ditambahkan inokulumAzotobacter sp. ataupun urea. Untuk masing-masing perlakuan dibuat 5 pengulangan, sehingga totalsemuanya ada 15 unit pot penelitian yang diinkubasi selama 14 hari di dalam Greenhouse BTL-BPPTyang kering dan terkena cahaya matahari. Tinggi tanaman S. bicolor diukur setiap hari selama 14 haripenelitian. Hasil penelitian menunjukkan bahwa penambahan Azotobacter sp. maupun ureaberpengaruh dalam meningkatkan pertumbuhan S. bicolor. Gradien kenaikan Az lebih tinggidibandingkan U, hal ini menunjukkan bahwa pengaruh penambahan inokulum Azotobacter sp. lebih tinggidibandingkan urea dalam meningkatkan pertumbuhan S. bicolor. Untuk menguji signifikansi pengaruhAzotobacter sp. terhadap pertumbuhan S. bicolor maka analisis variansi (ANOVA) dilakukan dan hasilnyamenunjukkan bahwa penambahan inokulum Azotobacter sp. berpengaruh signifikan terhadap tinggitanaman S. bicolor.