Charles L. Henry

Using municipal biosolids in combination with other residuals to restore metal-contaminated mining areas

High metal waste materials from historic mining at the Bunker Hill, Idaho (ID) Superfund site was amended with a range of materials including municipal biosolids, woody debris, wood ash, pulp and paper sludge, and compost. The existing soil or waste material has elevated metal concentrations with total Zn, Pb and Cd ranging from 6000 to 14 700, 2100 to 27 000 and 9 to 28 mg kg−1, respectively. Surface application of certain amendments including biosolids mixed with wood ash resulted in significant decreases in subsoil acidity as well as subsoil extractable metals. This mixture was sufficient to restore a plant cover to the contaminated areas. At the Bunker Hill site, a surface application of high N biosolids (44 or 66 tons ha−1) in combination with wood ash (220 tons ha−1) with or without log yard debris (20% by volume) or pulp and paper sludge (44 tons ha−1) was able to restore a vegetative cover to the metal contaminated materials for 2 years following amendment application. Plant biomass in 1999 was 0.01 mg ha−1 in the control versus a mean of 3.4 tons ha−1 in the residual amended plots. Metal concentrations of the vegetation indicated that plants were within normal concentrations for the 2 years that data were collected. Surface application of amendments was also able to reduce Ca(NO3)2 extractable Zn in the subsoil from about 50 mg kg−1in the control to less than 4 mg kg−1in two of the treatments. Use of conventional amendments including lime alone and microbial stimulants were not sufficient to support plant growth. These results indicate that surface application of biosolids in combination with other residuals is sufficient to restore a vegetative cover to high metal mine wastes.

Liming effects on availability of Cd, Cu, Ni and Zn in a soil amended with sewage sludge 16 years previously

A field study was conducted to determine the plant uptake of metals in soils amended with 500 Mg ha−1 of municopal sewage sludge applied 16 yr previously. Results showed that metals were available for plan uptake after 16 yr, but that liming greatly reduced the plant availability of most metals. The application of sludge also resulted in high rates nitrification and subsequent lowering of the soil pH before the uptake study was started. The sludge-amended soil (a mesic Dystric Xerochrept) was adjusted with lime one month prior to planting from an unlimed pH of 4.6 to pH 5.8, 6.5 and 6.9. Food crops grown were: (i) bush bean (Phaseolus vulgaris L. cv. Seafarer), (ii) cabbage (Brassica oleracea L. v. capitata L. cv. Copenhagen market), (iii) maize (Zea mays L. cv. FR37), (iv) lettuce (Lactuca sativa L. cv. Parris Island, (v) (Solanum tuberosum L. cv. (vi) tomato (Lycopersicum esculentum L. cv. Burpee VF). With the exception of maize, yields were significantly reduced in the unlimed sludge-amended soil. However, liming increased yields above the growth level of the unlimed untreated soil for cabbage, maize, lettuce, potato tuber and tomato fruit. Soluble and exchangeable of Cd. Ni and Zn were also reduced after liming the sludge-amended soil. In both limed and unlimed soils, the majority of the soil Cu was found in insoluble and unavailable soil fractions. To evaluate trace metal uptake, the edible portion of each crop was analyzed for Cd, Cu, ni and Zn. Liming redoced uptake of Cd, Ni and Zn in most crops, but generally did not change Cu, This study shows the benefit of pH adjustment in reducing relative solubility and plant uptake of metals as well as increasing crop yield in acid soils.

Use of municipal sludge to restore and improve site productivity in forestry: The pack forest sludge research program

Abstract Municipal wastewater residuals—sludge or biosolids—represent a major waste by-product from society that must be managed in responsible ways, and not released into aquatic systems or allowed to contaminate ground waters. Because of its high nutrient and organic matter content, sludge can be beneficially recycled into forest sites for site improvement purposes. Research to date on forest application of sludge has been very encouraging, clearly demonstrating the validity of this management technique. Forest sites typically display benefits in two ways: (1) an immediate growth response by both overstory and understory species; (2) a long-term improvement to the productivity of the site. However, for this practice to have broad utility and acceptance, it is critical that the concerns of the regulatory agencies and general public be addressed regarding public health and environmental issues through continued research. These concerns include the fate of trace metals, including movement, uptake and potential phytotoxicity, and passage into wildlife and human food cahin, the fate of pathogens, and leaching of nitrates into ground water systems. Many concerns are a result of misconceptions or misunderstandings of the potential problems involved and require working with these agencies and the general public through education and demonstration programs. This paper addresses the opportunities and problems that researchers at the University of Washington, College of Forest Resources have encountered while working in forest sludge applications during the past 20 years.

Long-term effects of heavy applications of biosolids on organic matter and nutrient content of a coarse-textured forest soil

Abstract Long-term changes in soil properties due to a single heavy application of municipal biosolids (municipal sewage sludge) on a coarse-textured glacial outwash soil were evaluated. Study sites, located at the University of Washingtons Pack Experimental Forest, 100 km south of Seattle, were clearcut, cleared, fertilized with 500 Mg ha −1 of municipal biosolids and planted a variety of tree species in 1975. Soil samples were taken in 1990 from three biosolids-amended forest stands and adjacent unamended control sites by horizon to a depth of 185 cm. Biosolids-amended samples had higher C (139 vs. 67 mg g −1 ), N (12 vs. 3.4 mg g −1 ), P (14 vs. 2.2 mg g −1 ) and S (2.5 vs. 0.4 mg g −1 ) contents in 0–7 cm mineral soil and other surface soil horizons compared with adjacent unamended soil horizons, but showed no significant differences below 25 cm. Soil pH ranged from 0.4 to 1.0 units lower in biosolids-amended vs. unamended soil throughout the sampled soil horizon. Soil cation exchange capacity was higher in the surface soil horizons (30 vs. 18 mmol c kg −1 in 0–7 cm soil), but there were no significant differences below 50 cm. Biosolids-amended samples had higher total Ca (13 vs. 6.1 mg g −1 in 0–7 cm soil) and K (1.9 vs. 1.5 mg g −1 in 0–7 cm soil) throughout the sampled soil profile. Total Mg was relatively constant (2.0–3.0 mg g −1 ) throughout the sampled soil profile. Study results indicate that one of the primary objectives of the original biosolids application (increasing total nutrients in the rooting zone of the forest soil) extended at least 15 years from the application date.

Treatment of Septic Effluent for Fecal Coliform and Nitrogen in Coarse-textured Soils: Use of Soil-only and Sand Filter Systems

Groundwater effluent sample collectors(zero-tension lysimeters) were installed directlybelow the drainfields of three residential onsitetreatment systems in the Clover/Chambers Creek aquiferregion of Pierce County near Tacoma, WA. The use of asplit effluent delivery system from the septic tank,where half the effluent was delivered under pressureto a normal native soil-only filter system and halfwas delivered to a sand filter system, allowed thedirect comparison of the two commonly-utilized septicsystems for treatment levels. Septic tank effluent(from the septic tank) and percolating water (between0.3 and 0.9 m beneath the effluent distributionlines) was collected between May 1991 and April 1994on 30 occasions. Samples were analyzed for fecalcoliform bacteria, nitrate, nitrite, ammonium andtotal reduced (Kjeldahl) nitrogen. Results of thisstudy indicate that the use of sand filters greatlyincreased removal of fecal coliform bacteria and totalnitrogen. Soil-only filter systems had an average of91% removal of fecal coliforms and 47%of total N; whereas sand filter systems had an averageof 99.8% removal of fecal coliforms and 80% of total N.

Potential emissions of volatile and odorous organic compounds from municipal solid waste composting facilities

Abstract The fraction of the municipal solid waste (MSW) stream that is composted is currently small, but increasing. Among the factors that may influence the extent to which MSW composting is adopted are potential emissions of volatile and odorous organics. Odor problems may be minimized through appropriate siting, design and operation. Failure to adequately anticipate odor control needs has, however, contributed to recent difficulties at several installations. Synthetic volatile organic compounds (VOCs) are likely to be present in MSW and are likely to be emitted to the air from composting processes. Projections indicate that indoor air quality may be of concern if buildings are inadequately ventilated. VOC releases appear unlikely to be off site concern.

Magnesium deficiency in Douglas-fir and Grand fir growing on a sandy outwash soil amended with sewage sludge

Soil and plant samples were collected from chlorotic plantations of Grand fir (Abies grandis) and Douglas-fir (Pseudotsuga menziesii) in Winter, 1989. The soils had been amended in 1981 with an average of 300 dry Mg ha−1 of municipal sewage sludge. The sludge amendment resulted in an N application rate of approximately 8000 kg ha−1. Foliage analysis indicated a severe Mg deficiency (0.25 g kg−1 in sludge-treated vs. 0.93 g kg−1 in untreated area) might be the cause of chlorosis. No other nutrient showed concentrations in the deficient or toxic ranges. Trace metal levels in foliage were elevated significantly for Ni, Cd and Cr in sludge-treated sites, but not toxic levels. Soil samples taken to a depth of 1.4 m indicated the potential for soil acidification (up to 0.9 pH unit) in soil surface horizons. In addition, exchangeable Ca, Mg and K may have been depleted in surface horizons. Exchangeable Al and Fe were greater in the surface of sludge-treated sites. These observations and the loss of much of the nitrogen added during the sludge amendment indicated that nitrification and cation leaching was likely the mechanism for acidification and depletion of exchangeable cations. Fertilization of the plantation with MgSO4 or dolomitic limestone was carried out in Spring 1990. New foliage collected in June, 1990 was non-chlorotic and significantly higher in Mg concentration than unfertilized foliage (1.1. vs. 0.7 g kg−1, respectively). Results of this study indicate that it is important to assess the potential for initiating a nutrient deficiency due to secondary effects of sludge application in forest systems.

Comparison of odor emissions from three different biosolids applied to forest soil

The odor emissions from three types of biosolidsfrom King County, WA, were measured usingdilution-to-threshold olfactometry and mass spectralanalyses. This article describes thermal desorption andcryogenic GC/MS methods developed to characterizeodorant emissions from biosolids application to forestsoil. The major odorous compounds volatilized from twoanaerobically digested biosolids were ammonia anddimethyl disulfide, with lesser quantities of carbondisulfide, dimethyl sulfide, trimethyl amine, acetoneand methyl ethyl ketone. A third type of biosolidswas formed by centrifuge and drying one of the otherbiosolids at 190 °C. This dry biosolids producedmore odor and volatilized a more complex array ofvolatile compounds including: dimethyl disulfide,dimethyl sulfide, carbon disulfide, methylethyldisulfide, methane thiol, trimethyl amine, aceticacid, propionic acid, and butyric acid. Odor unitemissions were not found to correlate with microbialactivity, initial biosolids ammonium, organicnitrogen, and total sulfur. Variability in odoremission were explained by the number of odorouscompounds volatilized from each material, surface areaof biosolids and drying of the biosolids.

Activated Carbon and Wood Ash Sorption of Wastewater, Compost, and Biosolids Odorants

Odor emissions from wastewater treatment facilities and composting operations and land application of biosolids are priority concerns for wastewater engineers, compost operators, and biosolids managers. High carbon wood ash is a material produced by the pulp and paper industry and cogeneration energy producing facilities; although this material has been found to have characteristics similar to activated carbon, it is currently treated as waste and deposited in landfills. To control odors associated with wastewater and biosolids, activated carbon and wood ash were exposed to odorants that often are associated with biosolids and wastewater, including dimethyl disulfide, dimethyl sulfide, carbon disulfide, ammonia, trimethyl amine, acetone, and methyl ethyl ketone. The sorption materials included activated carbon containing 87% carbon and wood ash residuals containing 32, 27, 6, and 0.24% carbon, with surface areas of 520, 85, 74, 25, and 2.1 m 2 /g, respectively. This laboratory sorption experiment was undertaken to examine sorption efficiency and kinetics of chemical odorants by activated carbon and wood ash residuals. Results demonstrate that wood ash with higher carbon concentrations and higher surface areas sorbed odorants better than low-carbon ash. Furthermore, the 32 and 27% carbon wood ash possessed characteristics similar to activated carbon and were able to sorb odorous gases effectively.

Mining Impacts on Trace Metal Content of Water, Soil, and Stream Sediments in the Hei River Basin, China

The impacts of mining to watersheds are highly variabledepending on the type of mining, processing of ores, andenvironmental factors. This study examined the Hei River incentral China, for impacts of gold and iron mining onconcentrations of metals in river water, river sediments andstream-channel soils. No production processing of ores occurson-site at either mine. Total metal content and extractablemetals using DTPA were determined. Total concentrations of Cd,Cu, Pb and Zn were high in some stream sediments and soils nearthe mine sites; metal concentrations ranged from 4–24, 11–100,11–380, and 33–1600 μg g-1 for Cd, Cu, Pb, and Zn,respectively, in soil. Total cadmium was high in all soilsand sediments. Extractable metals were low, with the exceptionof Pb and Cu. At the gold mine, extractable Pb ranged from 8 to33%; extractable Cu ranged from 3 to 21% of total metalconcentration. Chromium and Ni were not above typicalconcentrations in either soils or river sediments. An abundance of carbonates, high river water pH, and high water flow rates all appear to contribute to limiting quantities of metals in the river water. If mining activities are not changed, impacts of mining on downstream metal concentrations in river water should be nominal.