Mingxin Guo

Phosphorus release behaviors of poultry litter biochar as a soil amendment.

Phosphorus (P) may be immobilized and consequently the runoff loss risks be reduced if poultry litter (PL) is converted into biochar prior to land application. Laboratory studies were conducted to examine the water extractability of P in PL biochar and its release kinetics in amended soils. Raw PL and its biochar produced through 400°C pyrolysis were extracted with deionized water under various programs and measured for water extractable P species and contents. The materials were further incubated with a sandy loam at 20 g kg(-1) soil and intermittently leached with water for 30 days. The P release kinetics were determined from the P recovery patterns in the water phase. Pyrolysis elevated the total P content from 13.7 g kg(-1) in raw PL to 27.1 g kg(-1) in PL biochar while reduced the water-soluble P level from 2.95 g kg(-1) in the former to 0.17 g kg(-1) in the latter. The thermal treatment transformed labile P in raw PL to putatively Mg/Ca phosphate minerals in biochar that were water-unextractable yet proton-releasable. Orthophosphate was the predominant form of water-soluble P in PL biochar, with condensed phosphate (e.g., pyrophosphate) as a minor form and organic phosphate in null. Release of P from PL biochar in both water and neutral soils was at a slower and steadier rate over a longer time period than from raw PL. Nevertheless, release of P from biochar was acid-driven and could be greatly promoted by the media acidity. Land application of PL biochar at soil pH-incorporated rates and frequency will potentially reduce P losses to runoffs and minimize the adverse impact of waste application on aquatic environments.

Degradation of methyl iodide in soil: effects of environmental factors.

Methyl iodide (MeI) is a promising alternative to the phased-out fumigant methyl bromide (MeBr); however, there are concerns about its environmental fate following soil fumigation. Laboratory experiments were conducted to investigate the effect of various environmental factors on the rate of MeI degradation in soil. The chemical was added to soil at 48.6 mg kg(-1) and incubated under different conditions. The MeI degradation rate in soil was determined by extracting and measuring residual concentrations over a 15 d incubation period. In soil, MeI degradation followed availability-adjusted first-order kinetics. At 20 degrees C MeI had a calculated half-life of 32 d in a sandy loam containing 4.3 g kg(-1) of organic carbon. It degraded more rapidly as temperature increased, exhibiting a half-life of 23 d at 30 degrees C. Amendment with 10% cattle manure shortened the half-life to 4 d at 20 degrees C. In both unamended and manure-amended soils, the half-life of MeI greatly increased as the organic matter (OM) was removed and it only slightly increased in soils that were sterilized, indicating predominance of chemical reactions in MeI degradation. Soil texture, mineralogy, and moderate moisture content had little influence on MeI degradation. The degradation slowed as the chemical application rate increased. The results suggest that environmental factors, especially soil temperature and organic amendments, should be considered in combination with the minimum effective MeI application rate for achieving satisfactory pest-control efficacy, reducing atmospheric volatilization, and minimizing groundwater contamination.

Remediation techniques for heavy metal-contaminated soils: Principles and applicability

Globally there are over 20millionha of land contaminated by the heavy metal(loid)s As, Cd, Cr, Hg, Pb, Co, Cu, Ni, Zn, and Se, with the present soil concentrations higher than the geo-baseline or regulatory levels. In-situ and ex-situ remediation techniques have been developed to rectify the heavy metal-contaminated sites, including surface capping, encapsulation, landfilling, soil flushing, soil washing, electrokinetic extraction, stabilization, solidification, vitrification, phytoremediation, and bioremediation. These remediation techniques employ containment, extraction/removal, and immobilization mechanisms to reduce the contamination effects through physical, chemical, biological, electrical, and thermal remedy processes. These techniques demonstrate specific advantages, disadvantages, and applicability. In general, in-situ soil remediation is more cost-effective than ex-situ treatment, and contaminant removal/extraction is more favorable than immobilization and containment. Among the available soil remediation techniques, electrokinetic extraction, chemical stabilization, and phytoremediation are at the development stage, while the others have been practiced at full, field scales. Comprehensive assessment indicates that chemical stabilization serves as a temporary soil remediation technique, phytoremediation needs improvement in efficiency, surface capping and landfilling are applicable to small, serious-contamination sites, while solidification and vitrification are the last remediation option. The cost and duration of soil remediation are technique-dependent and site-specific, up to

Nutrient release and ammonium sorption by poultry litter and wood biochars in stormwater treatment.

500ton-1 soil (or

The origin and reversible nature of poultry litter biochar hydrophobicity.

1500m-3 soil or

Biochar-Amended Media for Enhanced Nutrient Removal in Stormwater Facilities

100m-2 land) and 15years. Treatability studies are crucial to selecting feasible techniques for a soil remediation project, with considerations of the type and degree of contamination, remediation goals, site characteristics, cost effectiveness, implementation time, and public acceptability.

Living in denial: climate change, emotions, and everyday life.

The feasibility of using biochar as a filter medium in stormwater treatment facilities was evaluated with a focus on ammonium retention. Successive batch extractions and batch ammonium sorption experiments were conducted in both deionized (DI) water and artificial stormwater using poultry litter (PL) and hardwood (HW) biochars pyrolyzed at 400°C and 500°C. No measureable nitrogen leached from HW biochars except 0.07 μmol/g of org-N from 400°C HW biochar. PL biochar pyrolyzed at 400°C leached 120-127 μmol/g of nitrogen but only 7.1-8.6 μmol/g of nitrogen when pyrolyzed at 500°C. Ammonium sorption was significant for all biochars. At a typical ammonium concentration of 2mg/L in stormwater, the maximum sorption was 150 mg/kg for PL biochar pryolyzed at 400°C. In stormwater, ion competition (e.g. Ca(2+)) suppressed ammonium sorption compared to DI water. Surprisingly, ammonium sorption was negatively correlated to the BET surface area of the tested biochars, but increased linearly with cation exchange capacity. Cation exchange capacity was the primary mechanism controlling ammonium sorption and was enhanced by pyrolysis at 400°C, while BET surface area was enhanced by pyrolysis at 500°C. The optimal properties (BET surface area, CEC, etc.) of biochar as a sorbent are not fixed but depend on the target pollutant. Stormwater infiltration column experiments in sand with 10% biochar removed over 90% of ammonium with influent ammonium concentration of 2mg/L, compared to only 1.7% removal in a sand-only column, indicating that kinetic limitations on sorption were minor for the storm conditions studied. Hardwood and poultry litter biochar pyrolyzed at 500°C and presumably higher temperature may be viable filter media for stormwater treatment facilities, as they showed limited release of organic and inorganic nutrients and acceptable ammonium sorption.

Transformation of Phosphorus in Speciation and Bioavailability During Converting Poultry Litter to Biochar

Transient changes in wettability complicate the prediction of biochars hydrologic effects. Biochar wetting properties were characterized from poultry litter biochar (PLBC) produced from slow pyrolysis at temperatures between 300 and 600°C with water drop penetration time (persistence of hydrophobicity) and contact angle (CA; severity of hydrophobicity) measurements. Hydrophobicity was associated with semivolatile organic compounds coating PLBC surfaces, which resulted in 24.4 carbon layers and CAs of 101.1 ± 2.9° at a pyrolysis temperature of 300°C but only 0.4 layers of surface coverage and CAs of 20.6 ± 1.3° when pyrolyzed at 600°C. Mixing PLBC with water removed organic coatings, and storage in water for 72 h decreased CA as much as 81° for the most hydrophobic PLBCs. When mixed with quartz sand of the same particle size, CAs of PLBC-sand mixtures increased from 6.6 ± 1.4° at 0% PLBC mass fraction to 48.3 ± 2.0° at 15% mass fraction. Hydrophobic and hydrophilic PLBCs increased CA by nearly identical amounts at 2 and 5% mass fractions, which was explained by the influence of PLBC particle topology on macroscopic surface roughness of PLBC-sand mixtures. For environmentally relevant situations, PLBC-sand mixtures at mass fractions ≤15% remained water wetting. However, all PLBC additions increased CA, which may alter infiltration rates and induce preferential water flow.

Fertilizer Value of Lime-Stabilized Biosolids as a Soil Amendment

Nutrients from roadway stormwater runoff contribute to eutrophication of water bodies. Although bioretention facilities remove many stormwater pollutants by precipitation, filtration, sorption, microbial degradation and plant uptake, limited removal of nitrogen compounds is often reported. This project explores a new technology incorporating biochar into the upper unsaturated soil media of bioretention facilities to enhance removal of nitrogen compounds. Biochar is a thermal decomposition product from biomass heated at relatively low temperature (<700C) with limited oxygen. Several studies have examined biochar as a surface sorbent to remove contaminants in the environment, utilizing the high internal porosity and surface area of this carbonaceous material. In this work, we report on biochar’s ability to increase removal of nitrogen compounds in bioretention media in two ways: sorption of ammonium, and increasing water retention and thus retention time for nitrogen cycling. Laboratory experiments were conducted to evaluate the ability of two types of biochar Soil Reef (SR) biochar (a commercial wood biochar) and poultry litter (PL) biochar to remove ammonium-nitrogen (NH4 -N). Ammonium sorption batch experiments showed 74%, 43%, and 37% of the input NH4 + was adsorbed by 0.2 g of, respectively, PL400-L (400 C pre-leached with DI water), PL500-L, and SR-L biochar in 10 mL 0.5 mg/L NH4 + solution. Water retention measurements indicated the volumetric water content of a uniform sand amended with 7% SR-L or PL300-L biochar was 4.5 or 2.3 times higher than pure sand at matric potential of -37 cm H2O. In conjunction with these laboratory data, we propose a pilot-scale test facility for quantifying nitrogen compound removal with biochar-amended bioretention media. 197 World Environmental and Water Resources Congress 2014: Water without Borders

Stream Nutrient Criteria for Evaluating Water Eutrophication and Biota Conditions

company that commercialized research he had developed while on the faculty. In addition to running the university, he now finds time to sit on the board of directors of Google and Cisco. Stanford not only aggressively encourages this kind of entrepreneurial effort, it provides significant resources to the surrounding Silicon Valley, including the development of a large industrial park that is now home to Facebook, Hewlett Packard, and numerous law firms, investment firms, and other players in the Valley’s success. But this example tugs at the heart of Mirowski’s narrative. Stanford is home as well to a major center of neo-liberal thought, the Hoover Institution, where Milton Friedman spent the latter period of his career. Yet far from a decoupling of the university from the private sector that Mirowski contends is the goal of the neo-liberal agenda, we find a particularly deep-seated partnership between the market and the academy. This partnership stretches back well into the Golden Age when, some have argued, it was really Stanford’s role to bring many private sector players to the table with figures from the Department of Defense in order to shape jointly the direction of Cold War science and strategy. And does Mirowski believe that scientists were ever as naı̈ve about either power or money in American society as he portrays Viridiana Jones to be? Was there an era in which the relationship between the intellectual and surrounding society was not deeply problematic? Certainly the Cold War era was not free of such conflict. In fact, one could argue that the field of science studies itself owes something to efforts like the Free Speech Movement at Berkeley in 1964 to recast our understanding of the modern university. The FSM was in part a reaction to the worldview of Clark Kerr, the president of the University of California from 1958 to 1967, and a leading architect of the modern higher education system. As early as 1963 Kerr, certainly no neo-liberal, coined the term ‘‘multiversity’’ and noted in The Uses of the University (Harvard 1963) that ‘‘the university and segments of industry are becoming more alike. As the university becomes tied into the world of work, the professor—at least in the natural and in some of the social sciences—takes on the characteristics of an entrepreneur’’ (p. 90). Kerr’s work sparked a response from two key figures at Berkeley, Hal Draper and Mario Savio. Draper’s widely circulated essay ‘‘The Mind of Clark Kerr’’ would savage Kerr, noting the irony of promoting the integration of the university with the wider world yet limiting the ability of students to engage in campus political organizing. Savio, in turn, used Draper’s work as intellectual capital to give birth to a new era of critical thinking about the university and society. While I question here the periodization that Mirowski relies upon, nonetheless, in doing so, he provides a powerful and compelling narrative of important trends in the world of science, the university and the wider economy. The book will be of significant value to scholars across numerous disciplines as the institution that sustains them weathers the important changes now underway.