Optimization of Biomethane Production via Fermentation of Chicken Manure Using Marine Sediment: A Modeling Approach Using Response Surface Methodology.

In this study, marine sediment (MS) was successfully used as a source of methanogenic bacteria for the anaerobic digestion (AD) of chicken manure (CM). Using MS showed high production in liquid and semi-solid conditions. Even in solid conditions, 169.3 mL/g volatile solids of chicken manure (VS-CM) was produced, despite the accumulation of ammonia (4.2 g NH3-N/kg CM). To the best of our knowledge, this is the highest methane production from CM alone, without pretreatment, in solid conditions (20%). Comparing MS to Ozouh sludge (excess activated sewage sludge) (OS), using OS under semi-solid conditions resulted in higher methane production, while using MS resulted in more ammonia tolerance (301 mL/gVS-CM at 8.58 g NH3-N/kg). Production optimization was carried out via a response surface methodology (RDM) model involving four independent variables (inoculum ratio, total solid content, NaCl concentration, and incubation time). Optimized methane production (324.36 mL/gVS-CM) was at a CM:MS ratio of 1:2.5 with no NaCl supplementation, 10% total solid content, and an incubation time of 45 days.

Reducing the Abundance of Harmful Bacteria of Rooftop Tank-Stored Drinking Water Using Silver Nanoparticles and Acetic Acid and Its Impact on Japanese Quail Growth Performances.

This study evaluated the microbial diversity of rooftop tank-stored drinking water consumed by Japanese quail (Coturnix coturnix japonica) using silver nanoparticles (AgNPs) and acetic acid (AC) and their mixture. Japanese quails (2 weeks old) of two different plumage colors, white and brown, were divided into four groups. In group 1 (control), birds received rooftop tank-stored water. In groups 2, 3, and 4, birds received rooftop tank-stored water treated with AC (0.5 mL/L), AgNPs (0.1 mg/L), or both AC and AgNPs. A reduction in the total coliform count was observed for AgNP- and AC-treated water after 2 h, 24 h, 48 h, and 5 days (P < 0.05). Growth rates and feed intake in both white- and brown-feathered quails were also increased using both AC and AgNPs (P < 0.05). A significant decrease in water consumption was observed in the brown-feathered quails, whereas the white-feathered quails drank more water (P < 0.05). Meanwhile, serum parameters remained unchanged in the white-feathered quails using both AC or/and AgNP purifiers (P > 0.05), whereas brown-feathered quails receiving water treated with AC or both AC and AgNPs displayed a significant increase in serum total protein and hemoglobin compared with quails receiving water treated with AgNPs alone or non-treated water (P < 0.05). Cholesterol and triglycerides levels were significantly increased when using both AC or/and AgNP purifiers (P < 0.05). In conclusion, both AgNPs and AC are recommended as efficient purifiers to eliminate pathogenic bacteria and to increase the growth performance and health condition of white- and brown-feathered Japanese quail birds.

Wastewater remediation of heavy metals and pesticides using rice straw and/or zeolite as bioadsorbents and assessment of treated wastewater reuse in the culture of Nile tilapia (Oreochromis niloticus).

The remediation of wastewater (WW) is a promising solution for limited water sources. This study aimed to evaluate rice straw (RS) and zeolite (Z) as bioadsorbents for the removal of pollutants, including heavy metals (HMs) (cadmium [Cd], nickel [Ni], and lead [Pb]) and malathion (PC), from WW and to assess the suitability of reusing remediated WW in fish rearing units. A total of 11 treatment groups with 3 replicates each were designed with different combinations of RS and/or Z for the treatment of real WW contaminated with HMs and malathion, where the WW remained in contact with the adsorbents for 24 h. Different remediated WWs were used for rearing Nile tilapia (Oreochromis niloticus), which were randomly allocated into 33 glass aquaria representing 11 treatments with 3 replicates each for 30 days. The best remediation efficiency was achieved using a mixture of whole RS (WRS), chopped RS (CRS), and Z (HM-PC-WRS-CRS-Z group), with removal percentages of 92%, 95%, 96%, and 99% for Cd, Ni, Pb, and malathion, respectively. The health status of the aquatic ecosystems was assessed through blood tests to characterize biochemical parameters and through pathological changes of cultured O. niloticus reared in treated WW. A significant (P Ë‚ 0.05) effect on the blood biochemistry of fish reared in treated WW was found and better biochemical and histologic architecture was observed than that of fish reared in untreated WW. A novel mixture of WRS, CRS, and Z could possibly be a promising low-cost adsorbent for wastewater treatment. Graphical abstract.

Dry Co-Digestion of Poultry Manure with Agriculture Wastes.

This study tested the effect on thermophilic and mesophilic digestion of poultry manure (PM) or treated poultry manure (TPM) by the addition of agriculture wastes (AWS) as a co-substrate under dry conditions. PM was co-digested with a mixture of AWS consisting of coconut waste, cassava waste, and coffee grounds. Results were increased methane content in biogas, with decreased ammonia accumulation and volatile acids. The highest performance occurred under mesophilic conditions, with a 63 and 41.3 % increase in methane production from addition of AWS to TPM (562 vs. 344 mL g VS(-1) from control) and PM (406 vs. 287 mL g VS(-1) from control), respectively. Thermophilic conditions showed lower performance than mesophilic conditions. Addition of AWS increased methane production by 150 and 69.6 % from PM (323.4 vs. 129 mL g VS(-1) from control) and TPM (297.6 vs. 175.5 mL g VS(-1) from control), respectively. In all experiments, 100 % acetate produced was degraded to methane. Maximum ammonia accumulation was lowered to 43.7 % by mixing of AWS (range 5.35-8.55 vs. 7.81-12.28 g N kg(-1) bed). The pH was held at 7.3-8.8, a range suitable for methanogenesis.

Enhancement of methane production from co-digestion of chicken manure with agricultural wastes.

The potential for methane production from semi-solid chicken manure (CM) and mixture of agricultural wastes (AWS) in a co-digestion process has been experimentally evaluated at thermophilic and mesophilic temperatures. To the best of author(')s knowledge, it is the first time that CM is co-digested with mixture of AWS consisting of coconut waste, cassava waste, and coffee grounds. Two types of anaerobic digestion processes (AD process) were used, process 1 (P1) using fresh CM (FCM) and process 2 (P2) using treated CM (TCM), ammonia stripped CM, were conducted. Methane production in P1 was increased by 93% and 50% compared to control (no AWS added) with maximum methane production of 502 and 506 mL g(-1)VS obtained at 55°C and 35°C, respectively. Additionally, 42% increase in methane production was observed with maximum volume of 695 mL g(-1)VS comparing P2 test with P2 control under 55°C. Ammonia accumulation was reduced by 39% and 32% in P1 and P2 tests.

Improved methane fermentation of chicken manure via ammonia removal by biogas recycle.

This study demonstrates methane fermentation that was carried out along with ammonia striping to avoid ammonia accumulation that significantly inhibited methane production. Ammonia was successfully removed by means of recycling of biogas followed by gas washing in sulfuric acid to capture ammonia, when chicken manure was anaerobically digested for 4 days at 55 degrees C and at an initial pH of 8-9. By using this method, 80% of total nitrogen in chicken manure was converted to ammonia and 82% of the produced ammonia was removed. A bench scale reactor equipped with an ammonia-stripping unit for methane production from chicken manure was developed and operated in repeated batch mode. At an initial pH of 8 and at 55 degrees C, 195 and 157 ml g-VS(-1) of methane was successfully produced from the treated chicken manure and the mixture of treated chicken manure and raw chicken manure in the ratio of 1:1, respectively. In this method, ammonia concentration was maintained at a level lower than 2g-N kg-wet sludge(-1) in the reactor.

Dry mesophilic fermentation of chicken manure for production of methane by repeated batch culture.

The dry fermentation of chicken manure (CM) for production of methane in mesophilic conditions at 37 degrees C was studied under laboratory conditions using a repeated batch culture system. Methane was successfully produced after an acclimation period of about 254 d. A total volume of 4.4 l kg(-1) CM (31 ml g(-1)VS) of methane gas was produced, despite the presence of a high level of ammonia of ca. 8 to 14 g-N kg(-1) CM. This clearly demonstrates that spontaneous acclimation of the methanogenic consortia to high levels of ammonia could occur and result in production of methane even under a high percentage of total solid (25%) and a high level of ammonia.

Dry anaerobic ammonia-methane production from chicken manure.

The effect of temperature on production of ammonia during dry anaerobic fermentation of chicken manure (CM), inoculated with thermophilic methanogenic sludge, was investigated in a batch condition for 8 days. Incubation temperature did not have a significant effect on the production of ammonia. Almost complete inhibition of production of methane occurred at 55 and 65 degrees C while quite low yields of 8.45 and 6.34 ml g(-1) VS (volatile solids) were observed at 35 and 45 degrees C due to a higher accumulation of ammonia. In order to improve the production of methane during dry anaerobic digestion of CM, stripping of ammonia was performed firstly on the CM previously fermented at 65 degrees C for 8 days: the stripping for 1 day at 85 degrees C and pH 10 removed 85.5% of ammonia. The first-batch fermentation of methane for 75 days was conducted next, using the ammonia-stripped CM inoculated with methanogenic sludge at different ratios, (CM: thermophilic sludge) of 1:2, 1:1, and 2:1 on volume per volume basis at both 35 and 55 degrees C. Production of methane improved and was higher than that of the control (without stripping of ammonia) but the yield of 20.4 ml g(-1) VS was still low, so second stripping of ammonia was conducted, which resulted in 74.7% removal of ammonia. A great improvement in the production of methane of 103.5 ml g(-1) VS was achieved during the second batch for 55 days.