THE USE OF ACTIVATED SEWAGE SLUDGE IN BROILER DIETS

The effect of dried activated sewage sludge on the growth and protein utilization of broiler was studied. The eight weeks feeding trial involving one hundred and eighty day-old broiler chicks, weighting 57.80 – 58.00g in a completely randomized design were fed three diets containing 0% (control), 10% and 15% dried activated sewage sludge. The dried activated sewage sludge was found to be high in protein and ash (24.24% and 41.80%) but low in either extract and fibre (3.0% and 3.50%) respectively. At the 10% level of inclusion in the diet, the activiated sewage sludge gave significantly (P < 0.05) better weight gains than the control and 15% levels of inclusion. The feed efficiency and protein efficiency ratios were also significantly (P < 0.05) better at 10% inclusion when compared with the control and 15% levels of inclusion. There was no incidence of enteritis and percentage mortality was statistically insignificant at 5% level.

COMPARATIVE UTILIZATION OF SEWAGE SLUDGE, POULTRY DROPPINGS AND GROUNDNUT CAKE RATIONS BY WEST AFRICAN DWARF GOATS

Eighteen young West African dwarf (WAD) goats were used to compare the utilization of sewage sludge, poultry dropping and groundnut cake rations by WAD goats. Total dry matter intake of the animals fed diet A (groundnut cake based ration) and C (poultry dropping based ration) was significantly (P < 0.05) higher than dry matter intake of animal fed diet B (dry activated sewage sludge based ration). Total dry matter intake of animal fed diet A (664.6 g/day) appeared to be higher than those fed diet C (600.5g/day), although the differences observed were and significant. Values observed for apparent dry matter, ether extract and nitrogen-free extract digestibilities between animals fed the different diets were not significant (P > 0.05). crude fibre and crude protein digestibility values however varied appreciably. Values recorded (12.03, 1.04 and 10.42 g/day and 3.13, 0.28 and 2.72 g.day/w 0.75kg for animals fed diets A, B, and C respectively) for nitrogen balance and weight gains (56.8, -2.7 and 36.8 g/day for animals fed diets A, B and C respectively) were higher for animals fed diet A, followed by animals fed diets C and B respectively.

Hydrothermal carbonization of activated sewage sludge over ammonia-treated Fenton sludge to produce hydrochar for clean fuel use

Fenton sludge was hydrothermally treated with ammonia (ATFS) and used as a catalyst for the hydrothermal carbonization (HTC) of activated sewage sludge (ASS) to produce a hydrochar for fuel use.

Adsorptive desulfurization of diesel using activated sewage sludge: kinetics, equilibrium and thermodynamics studies

Combustion of fossil fuels gives rise to sulfur oxides, which are harmful to the environment. Adsorptive desulfurization (ADS) of diesel was conducted using sewage sludge activated with H2O2 as the oxidizing agent. A full 22 central composite response surface design was employed to determine optimum conditions for the production of activated sewage sludge (ASS). The adsorbent (ASS) was characterized using SEM, EDX and FTIR and the results of the analysis showed that it has the capacity to desulfurize diesel significantly. The ASS was subsequently used to conduct batch ADS of diesel with a view to investigate the kinetics, equilibrium and thermodynamics of the process. The optimum conditions established for the production of ASS using H2O2 as the oxidizing agent were: temperature 400 °C and holding time 60 min. The Elovich model gave the best fit to the kinetic data of the ADS of diesel using ASS, while the equilibrium study showed that the Freundlich isotherm fitted the data at 35 °C better than Temkin and Langmuir isotherms. The positive values of the free energy and enthalpy changes revealed that the process was non-spontaneous and endothermic, respectively, while the negative entropy change is evidence of decrease in randomness of the adsorbed species. 33% desulfurization was achieved in 100 min during ADS of diesel showing that the adsorbent developed by activating SS with H2O2 was very good and effective. Thus, ASS can be used to gain more insight into kinetics, equilibrium and thermodynamics of the ADS of middle-distillate petroleum fractions.

Primary and Activated Sludge Biogas Production: Effect of Temperature

Sewage sludge management is a problem of growing importance. Anaerobic sewage sludge stabilization is commonly used technology, where organic matter contained in primary and activated sewage sludge is converted into biogas, so both, pollution control and energy recovery can be achieved. The paper deals with the effect of process temperature (36 °C, 42 °C and 50 °C) on biogas production and quality during anaerobic stabilization of primary and activated sewage sludge generated during purifying process in low‑loaded activated sludge process. Primary and activated sewage sludge samples were taken at the wastewater treatment plant Brno, Czech Republic. The characteristics of sludges (dry matter and organic dry matter content, pH, conductivity, redox potential) were dermined. Biogas production and quality was measured using 3 anaerobic systems, each of 8 batch anaerobic fermenters, at the 3 different temperature conditions 36 °C, 42 °C and 50 °C. Hydraulic retention time was 20 days. Hypothesis, which predicts that the fermentation of primary and activated sludge provides dissimilar methane quantity and quality under different temperature conditions (36 °C, 42 °C and 50 °C), was partially confirmed. Temperature 42 °C significantly increased biogas production from primary sewage sludge (by 60 % in comparison with production at 36 °C). For activated sewage sludge samples no significant influence of temperature on the biogas production was observed.