Refereed Journal Articles
Ndegwa, P.M., D.W. Hamilton, J.A. Lalman, H.J. Cumba. 2005. Optimization of Anaerobic Sequencing Batch Reactors (ASBRs) Treating Dilute Swine Slurries.Trans. of the ASAE 48(4): 1575-1583.
Zhu J., Luo, A., Zhou, Y., Ndegwa, P.M., Schmidt, D.R. 2004. The Age Effect of Dairy Feedlots on Manure Nutrient Seepage in Loam Soils. Biosystems Engineering 89 (2): 223-229.
Ndegwa, P.M., 2004. Solids Separation Enhances Reduction of Organic Strength of Swine Manure Subjected to Aeration Treatments. Trans. of the ASAE 47(5):1659-1666.Zhu, J., A. Luo, Y. Zhou, Ndegwa, P.M., D. Schmidt. 2004. Nutrient Seepage from Operating Turkey Buildings with a Litter System. Water, Air, and Soil Pollution 155(1-4): 87-101.
Ndegwa, P.M. 2004. Limitations of Orthophosphates Removal during Anaerobic Batch Treatment of Piggery Slurry. Biosystems Engineering 87(2):201-208.
Zhu, J., Ndegwa, P.M., Z. Zhang. 2004. Manure Sampling Procedures and Nutrient Estimation by the Hydrometer Method for Gestation Pigs. Bioresource Technology 92(3):243-250.
Ndegwa, P.M., J. Zhu, A. Luo. 2003. Effects of Bioreactor Temperature and Time on Odor-Related Parameters in Aerated Swine Manure Slurries. J. Environ. Technology 24(8): 1007-1016.
Ndegwa, P.M., J. Zhu, A. Luo, D.W. Hamilton. 2003. Enhanced Phosphorus Removal from Swine Manure in Aerated Batch Reactors. Trans. of the ASAE 46(3): 797-803.
Zhu, J., Ndegwa, P.M., A. Luo. 2003. Temperature Effects on Pig Manure under Low-Level Batch Aeration. The International Journal of Environ. Studies 60(5): 523-533.
Ndegwa, P.M., J. Zhu. 2003. Sampling Procedures for Piggery Slurry in Deep Pits for Estimation of Nutrient Content. Biosystems Engineering 85(2): 239-248.
Ndegwa, P.M. 2003. Solids Separation Coupled With Batch-Aeration Treatment For Odor Control From Liquid Swine Manure. J. Environ. Sci. Health B38(5): 631-643.
Zhu, J., Z. Zhang, Ndegwa, P.M.. 2003. Using a Soil Hydrometer to Measure the Nitrogen and Phosphorus Contents in Pig Slurries. Biosystems Engineering 85(1): 121-128.
Ndegwa, P.M., J. Zhu, A. Luo. 2003. Discussions and Closure to “Effects of Solids Levels and Chemical Additives on Removal of Solids and Phosphorus in Swine Manure”. J. Environ. Eng.-ASCE 129(5): 485-487.
Zhu, J., Ndegwa, P.M., Z. Zhang. 2003. Settling Characteristics of Nursery Pig Manure and Nutrient Estimation by the Hydrometer Method. J. Environ. Sci. Health B38(3): 379-390.
Zhu, J., A. Luo, Y. Zhou, Ndegwa, P.M., D. Schmidt. 2002. Barn Age Impact on Nutrient Leaching from Turkey Barns Built on Clay Loam Soils. Trans. of the ASAE 45(6): 1971-1976.
Ndegwa, P.M., J. Zhu, A. Luo. 2002. Influence of temperature and time on phosphorus removal in swine manure during batch aeration. J. Environ. Sci. Health B38(1): 73-87.
Luo, A., J. Zhu, Ndegwa, P.M.. 2002. Influence of anaerobic pre-conditioning on phosphorus removal in swine manure by aeration. J. Water, Air, and Soil Pollution 140(1-4): 219-230.
Ndegwa, P.M., J. Zhu, A. Luo. 2002. Stratification of Solids, Nitrogen and Phosphorus in Swine Manure in Deep Pits Under Slatted Floors. Bioresource Techno. 83(3): 203-211.
Zhu, J., Ndegwa, P.M., A. Luo. 2002. Bacterial Responses to Temperature during Aeration of Pig Slurry. J. Environ. Sci. Health B37(3): 265 - 275.
Luo, A., J. Zhu, Ndegwa, P.M.. 2002. Removal of Carbon, Nitrogen, and Phosphorus in Pig Manure by Continuous and Intermittent Aeration at Low Redox Potentials. Biosystems Eng. 82(2): 209-215.
Ndegwa, P.M., J. Zhu, A. Luo. 2002. Effects of Solids Separation and Time on the Production of Odorous Compounds in Stored Pig Slurry. Biosystems Engineering 81(1): 127-133.
Thompson, S.A, Ndegwa, P.M., W.C. Merka, A. B. Webster. 2001. Reduction in Manure Weight and Volume Using an In-House Layer Manure Composting System under Field Conditions. Applied Poultry Research 10(3): 255-261.Zhu, J., Ndegwa, P.M., A. Luo. 2001. Effect of solid-liquid separation on BOD and VFAs in swine manure. J. Environmental Technology 22(10): 1237-1243.
Ndegwa, P.M., J. Zhu, A. Luo. 2001. Effect of Batch Aeration-Treatment on the Solubility of Phosphorus in Pig Manure. J. Agricultural Engineering Res. 80(4): 365-371
Zhu, J., A. Luo, Ndegwa, P.M.. 2001. Raising pH by Low Level Aeration for Soluble Phosphorus Removal from Swine Manure. Transactions of the ASAE 44(2): 391-396.
Ndegwa, P.M., J. Zhu, A. Luo. 2001. Effects of Solids Levels and Chemical Additives on Removal of Solids and Phosphorus in Swine Manure. J. Environmental Engineering-ASCE 127(12): 1111-1115.
Luo, A., J. Zhu, Ndegwa, P.M.. 2001. Phosphorus Transformations in Swine Manure during continuous and intermittent Aeration Processes. Transactions of the ASAE 44(4): 967-972.
Ndegwa, P.M., S.A.Thompson. 2001. Integrating Composting and Vermicomposting in the Treatment and Bioconversion of Biosolids. Bioresource Technology 76(2): 107-112.
Zhu, J., A. Luo, Ndegwa, P.M.. 2001. The Effect of Limited Aeration on Swine Manure Phosphorus Removal. J. Environ. Sci. Health B36(2): 209-218.
Ndegwa, P.M., S.A.Thompson. 2000. Effects of C-to-N Ratio on Vermicomposting of Biosolids. Bioresource Technology 75(1): 7-12.
Zhu, J., Ndegwa, P.M., A. Luo. 2000. Changes in Swine Manure Solid Components During Storage Relating to Separation Efficiency. Applied Engineering in Agriculture 16(5): 571-575.
Ndegwa, P.M., S. A. Thompson, W. C. Merka. 2000. A Dynamic Simulation Model of in-situ Composting of Caged-Layers’ Manure. Compost Sci. & Utilization 8(3): 190-202.
Ndegwa, P.M., S.A.Thompson, K.C. Das. 1999. Effects of Stocking Density and Feeding Level on Vermicomposting of Biosolids. Bioresource Technology 71(1): 5-12.
Ndegwa, P.M., S. A. Thompson, W. C. Merka. 1991. Fractionation of Poultry Litter for Enhanced Utilization. Transactions of the ASAE 34(3): 992-997.
"Something in the Air"
Dr. Pius Ndegwa
Biological Systems Engineering
Washington State University
LJSmith 202, P.O. Box 64120
Pullman, Wasington 99164-6120
Phone:
509 335-8167
Fax:
509 335-2722
Electronic Mail:
ndegwa@wsu.edu