Long-term land application of biosolids-a case study.

Impact of long-term land application of biosolids on groundwater and soil quality of an application site, which had been operated for 8-15 years, was evaluated in this study. During and after the biosolids application, biosolids-amended soil, groundwater, and background soil samples were collected mainly for pathogen, nitrogen, phosphorus, and heavy metal analyses. Soil test data showed that there was no heavy metal accumulation in the biosolids-amended soil even after 10 years of biosolids application. Similar results were also observed from the groundwater samples in which the heavy metal concentrations in all groundwater samples were well below the maximum contamination levels of the drinking water standards. In addition, bacteriological levels of the soil and groundwater samples were close to the background level and below the permissible limits, respectively, thereby showing no pathogen contamination. However, nitrate-nitrogen contamination of the groundwater was occasionally observed probably due to an excess loading of the biosolids in the past. This problem can be alleviated by applying biosolids at agronomic rates so that no excess nitrogen is available for leaching down to the groundwater.

Integrated advanced natural wastewater treatment system for small communities.

A study was conducted to evaluate the nutrient removal capability of an existing and successfully operated overland flow and wetland wastewater treatment system following a waste stabilization pond. Seasonal temperature effects on performance were also investigated. The treatment system studied consists of a two-cell waste stabilization pond followed by an overland flow system and a wetland system. The influent and effluent samples were analyzed for BOD5, suspended solids (SS), pH, temperature, ammonia nitrogen, nitrate nitrogen, and total phosphorus. The results of the study indicate that the combined pond, overland flow and wetland system provided excellent treatment of municipal wastewater. The overall average BOD5 removal by the entire treatment system was about 90.0% and the overall average suspended solids removal was about 93.4%. The ammonia nitrogen and total phosphorus removal efficiencies of the entire treatment system were 90.7% and 84.2%, respectively.

Deregulation and cross talk among Sonic hedgehog, Wnt, Hox and Notch signaling in chronic myeloid leukemia progression.

Deciphering the BCR-ABL-independent signaling exploited in chronic myeloid leukemia (CML) progression is an important aspect in cancer stem-cell biology. CML stem-cell compartment is dynamic as it progresses to terminal blast crisis where myeloid and lymphoid blasts fail to differentiate. We demonstrate cross-regulation of signaling network involving Sonic hedgehog (Shh), Wnt, Notch and Hox for the inexorable blastic transformation of CD34(+) CML cells. Significant upregulation in Patched1, Frizzled2, Lef1, CyclinD1, p21 (P < or =0.0002) and downregulation of HoxA10 and HoxB4 (P< or =0.0001) transcripts in CD34(+) cells distinguish blast crisis from chronic CML. We report Shh-dependent Stat3 activation orchestrates these mutually interconnected signaling pathways. Stimulation of CD34(+) CML cells with either soluble Shh or Wnt3a did not activate Akt or p44/42-mitogen activated protein kinase (MAPK) pathways. Interestingly, unlike dominant negative Stat3beta, introduction of constitutive active Stat3 in CD34(+) CML cells induces cross-regulation in gene expression. Additionally, Shh and Wnt3a-dependent regulation of cyclin-dependent kinase inhibitors (CDKI) in CML suggests their role in the network. Taken together, our findings propose that deregulation in the form of hyperactive Shh and Wnt with repressed Notch and Hox pathways involving Stat3, Gli3, beta-catenin, CyclinD1, Hes1, HoxA10 and p21 might act synergistically to form an important hub in CML progression.

Development of sludge based stable aqueous Bacillus thuringiensis formulations.

This study focuses on development of aqueous flowable (suspension) formulations for Bacillus thuringiensis (Bt) based biopesticides from wastewater sludge. Different inerts like sorbitol, sodium monophosphate, sodium metabisulphite, sorbic acid, propionic acid, Tween-80, Triton X-100 and glycerol were tested for formulations. Five different formulations for non-hydrolyzed (NH) secondary sludges were tried and the best combination selected on the basis of various physical parameters like viscosity, particle size, suspendibility, entomotoxicity, and microbiological purity tests. F5 formulations (for secondary sludge) comprising sorbitol, sodium monophosphate and sodium metabisulphite gave better physical and biological characteristics with a small effect on entomotoxicity and spore concentration after 120 days at pH 6, 6.5 and temperatures 40 and 50 degrees C and viscosity change at 40 and 50 degrees C. The formulations were more stable at pH 4.0 to 5.0 and temperatures 4 to 30 degrees C whereas at pH 6.0 and 6.5 and temperatures 40 and 50 degrees C, there was degeneration of the product. Lower proteolytic activity and physical factors like ionic strength and surface group changes at pH 6 and 6.5 were responsible for the instability of the formulation.

The determination of radioisotope levels in municipal sewage sludge.

Sludge samples from 25 municipal waste water treatment plants have been analyzed to determine the level of environmentally present, man-made, gamma-ray emitting radioisotopes. Samples were freeze dried and separated into dried sludge, liquid-soluble and liquid-insoluble components. These were counted in the low background level, whole body counter at Missouri University using a standard intrinsic-Germanium spectrometer. After freeze drying, the liquid effluents from the samples were not found to have statistically significant levels of radioactivity. Using log-normal analysis, the dried sludge was found to have 0.0016 +/- 0.0022 Bq g-1 (0.04 +/- 0.06 pCi g-1) of 137Cs and 0.001 +/- 0.003 Bq g-1 (0.03 +/- 0.08 pCi g-1) of 60Co. These data can be used to determine if sewage effluents from nuclear facilities have levels of radioactivity above that expected from the environment.