Yusuf M.O.L., Debora A., Ogheneruona D.E., 2011. Ambient temperature kinetic assessment of biogas production from co-digestion of horse and cow dung. Res. Agr. Eng., 57: 97-104.Biogas production from 5 batch digesters containing varying ratio of mix of horse and cow dung was studied for a period of 30 days at ambient temperature. It was observed that biogas production was optimized when horse and cow dung were mixed in a ratio of 3:1. The modified Gompertz equation was used to adequately describe the cumulative biogas production from these digesters. In addition, a modified first order model was developed to assess the kinetics of the biodegradation process. It was observed that the rates of substrate biodegradability and of removal of the biodegradable fractions of the substrate could be obtained by plotting 1/t (ln(dyt/dt)) against the inverse of time of digestion. This modified first order model also showed that the digester containing horse dung and cow dung in the ratio of 3:1 had the highest short term anaerobic biodegradability index (STABI) of 3.96 at room temperature.

No abstract

Abstrak Dalam ilmu perbaikan tanah, telah dikenal beberapa metode perbaikan tanah baik yang bersifat primitif/tradisional maupun yang sudah menggunakan teknologi maju. Oleh karena pekerjaan pembangunan dibatasi biaya maka metode-metode perbaikan yang murah tetapi stabil masih memerlukan inovasi yang terus akan berkembang. Lagi pula, suatu metode perbaikan biasanya hanya cocok untuk kondisi tertentu antara lain menurut jenis tanahnya. Tanah gambut di Pontianak yang secara teknik tidak menguntungkan, telah diterapkan beberapa metode perbaikan/perkuatan tanah namun masih sering terjadi kegagalan sehingga masih memerlukan metode perbaikan yang efektif dan efisien dengan biaya yang minimal. Penelitian ini mengkaji metode perkuatan dengan tiang cerucuk yang divariasikan dengan berbagai formasi menurut panjang, jarak, diameter, dan jumlahnya dalam satu grup. Dari berbagai formasi tersebut, jumlah tiang dan diameter merupakan variabel yang paling menentukan. Dengan pendekatan bahwa beban ultimit berbanding linier terhadap variasi yang ditinjau diperoleh hubungan Pu = 1497,217985 + 101,5289346N + 114,4953539D. Setelah dilakukan uji pembebanan diperoleh bahwa beban ultimit hasil uji pembebanan hanya sebesar 20% dari beban ultimit menggunakan data uji laboratorium. Kata-kata kunci: pelat beton, tanah gambut, tiang cerucuk, kelompok tiang, uji pembebanan

Aim: The study aimed at evaluating pollutants present in soil due to slaughterhouse wastewater discharge into surrounding land mass as well as comparing land deposition as an alternative means of discharge. Study Design: The study design was based on Investigative Survey Research Approach (ISRA). The ISRA for obtaining data entailed schedule of series of visits to slaughterhouse facilities. The tasks accomplished during such visits included the following: Inspection and witnessing processing operations within and around the sampled slaughterhouses; interviewing relevant and competent staff of the slaughterhouses and residents living in areas close to the slaughterhouses; Collection of soil samples at specified depth intervals within the discharge points of selected land based slaughterhouses for laboratory analysis. Methodology: A total of twelve composite samples were collected from three different land discharged locations. Three composite samples each were collected from the sampling locations at a depth of 0 to 10 cm, 10 to 20 cm, 20 to 30 cm and 30 to 40 cm. Four composite samples each were collected for analysis from the three sampling locations on specified sampling dates. The samples were then placed in sterile polythene bags and transported to the laboratory for processing. Results: A high build-up of heavy metal concentration was observed in soil samples from all the sampled locations across their examined depths. Mn had the highest average concentration across the depths followed by Zn, Pb and Cd as shown from sampled results of LA1, LA2 and LA3. The average concentrations of Mn, Zn, Pb, and Mn decreased across the depths for all examined sites except for a truncated build-up of Zn and Mn at depths 30-40cm and 10-20 cm respectively. Conclusion: From the results obtained therefore, it was revealed that effluent/solid wastes generated from the slaughterhouse is highly polluted and has a huge effect in nutrient build-up, hence, there is an urgent need for basic treatment of wastes before discharge to land.

Aim: The study aimed at modeling the concentration of pollutants along soil profile using finite element method. Study Design: Data was generated from the laboratory on the concentrations of selected heavy metals at varying depths of land discharged slaughterhouses. This was used to estimate the level of nutrient build-up in the soil within these environs, hence, used to verify and validate the finite element analysis. The model upon validation was used to predict the rate of pollutant build-up in the soil within the slaughterhouses discharge areas. Methodology: A total of twelve composite samples were collected from three different land discharged locations. The three composite samples each were collected from the sampling locations at a depth of 0 to 10cm, 10 to 20cm, 20 to 30cm and 30 to 40cm. Four composite samples each were collected for analysis from the three sampling locations on specified sampling dates. The samples were then placed in sterile polythene bags and transported to the laboratory for processing. The laboratory results obtained for heavy metals were used for the generated model verification and validation, hence predictions for pollutants accumulation was done on a time step. Results: Model verification showed a good fit of a nonlinear polynomial curve for both the measured and predicted values with R² values of 0.9978 to 0.9985 for zinc and 0.9978 to 0.9984 for lead at a selected time step of 15years. It was observed however, that there was an increasing tendency to uniformity of concentration as the time step increased; this was due to parameters build-up with time in the soil. Conclusion: Finite element results revealed a high build-up in the concentration of pollutants (Zinc and Lead) in the land discharged slaughterhouses.