SOLUCORP

MBS - Molecular Bonding System

Your cost effective & permanent solution to metals contamination in soils & liquid waste.

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INTRODUCTION

MBS is an EPA "SITE" (Superfund Innovative Technology Evaluation) program technology, proven successful at the Midvale Slag Superfund site and on dozens of other commercial applications. It provides simple, environmentally sound and cost effective stabilization of heavy metals contamination. MBS effectively stabilizes all RCRA and UTS metals and, with minimal reagent addition will permanently reduce the leachability of metals in soil, sludge, slag, baghouse dust and ash to levels significantly below regulatory limits. Heavy metals are chemically transformed into their metallic sulfides (a metal's most insoluble form). The processed material is pH balanced, non-hazardous, and unchanged in physical characteristics. In addition to the TCLP test, MBS has been subjected to and passed other regulatory methods such as SPLP, SWEP, CAL WET and the Humidity Cell and MEP long term stability tests.

MBS APPLICATIONS
MBS on-site operations may be completed either ex-situ or in-situ using standard mixing equipment. MBS is proven for wastes classified as D004 through D011, as well as K-listed wastes. MBS has effectively treated sludges, filter-cake, slag, paint chips, auto fluff and various types of clay, soil, gravel and sand.

Ex-Situ Operations
Solucorp maintains several mobile treatment systems that can be brought to your site and set up within a matter of hours or days, depending on project size. Processing rates range from 25 tons per hour to more than 250 tons per hour. Waste material is screened and crushed to 2" or less in diameter. The waste is then blended with MBS powdered reagents in a closed hopper pugmill system. Water may also be added at the pugmill to increase moisture content to 15% to 20% and to promote uniform mixing. Treaded soil exits the pugmill on a conveyor and is stockpiled.

In-Situ Operations
MBS powdered reagents can be applied using traditional tilling methods by blending reagents into the soil with appropriate equipment. Powdered reagents are stored in bags or various sized silos with variable off loading augers. Water may be necessary to enhance dispersion of reagents throughout the matrix being processed. After the reagents and water have been applied to the surface and permeated the ground, soils are mixed to homogeneity to a depth of up to two feet with either a backhoe, rototiller or other tilling/discing equipment without any excavation of material. MBS can also be applied in a slurry form.

In-Line Treatment
The MBS process can easily be integrated into a manufacturing line to stabilize a heavy metal waste so it can be classified as non-hazardous. This means a safer facility, lower insurance, compliance, training and disposal costs. The MBS in-line treatment unit design is typically a simple mixing system, such as a pugmill. This system can be placed in various locations on the production line, with the optimal location based on factors such as: regulatory compliance issues, feed rate, material handling requirements and others. Solucorp's engineering staff will customize a system to best capitalize on the specific conditions present at your facility.


MBS PROCESS CHEMISTRY
In the MBS process, an inorganic sulfide reacts with the metal compounds in the waste, converting leachable metallic ions into non-leaching molecules. A proprietary reagent is used to minimize or completely eliminate hydrogen sulfide off-gassing, and to provide long-term buffering capacity. An additional reagent is utilized to inhibit long-term oxidation.

MBS is composed of three or four reagents which are utilized in proportions established by Solucorp's benchscale treatability study. These reagents are normally provided as a single dry blend. The benefits and superiority of the MBS stabilization system as compared to cement, lime, phosphate and other mineralization systems are seen in the fact that metal sulfides are known to be much more stable and to exhibit much lower solubilities. Reagent additions are very low, usually in the range of 2% to 5% by weight of waste, and the increase in volume of the waste attributable to stabilization is usually less than 3%. In some cases, a volume reduction will occur.


PHYSICAL CHARACTERISTICS
The physical characteristics of MBS treated wastes are not changed by the process. The treated wastes appearance will be basically unchanged. Additionally, there is no curing time, as the MBS chemical reaction occurs immediately. Unconfined compressive strength may be slightly increased and permeability may be slightly reduced. Moisture content should be near optimum, yielding a treated soil which is ideal for use as contour or fill. Unlike other technologies, since physical characteristics are unchanged, material handling is easier.


TECHNICAL CONSIDERATIONS
Conventional cementitious stabilization systems rely heavily on pH control, and these systems are usually evaluated using EPA's TCLP as the criterion for measuring the success of the process. TCLP analysis is conducted using a buffered acid as the leaching medium to evaluate the potential for leaching under worst case acid conditions. Cement-based systems are strongly alkaline, so they can overpower the acid used in a TCLP test and complete the leaching process in a mildly alkaline environment.

The MBS process has been developed to avoid the potential leaching problem of cement-based systems. The leaching characteristics of the metal sulfides that are formed are not pH sensitive. Final pH values in the TCLP extract, of MBS treated wastes are often in the 5 to 6 range. This condition would result in failure of cement-based systems. The tolerance of the MBS process to low pH has been demonstrated by its resistance to leaching in the repetitive acid environment of the Multiple Extraction Procedure (MEP) test.


SUMMARY & CONCLUSIONS
MBS is the most effective system to chemically alter the form of heavy metal contaminants into a non-hazardous, stable compound. The simplicity of the MBS process combined with its modular / transportable design and fully enclosed operational system (preventing the release of contaminants or secondary wastes), provides lower operating costs, enhanced safety and reduced emissions / secondary wastes.

The inherent ability of MBS to transform hazardous contaminants into non-hazardous, insoluble compounds can facilitate on-site disposal of a variety of wastes. The MBS process can also be easily integrated into a manufacturing line. The result is a safer site or facility and significantly reduced liability.

When off-site disposal is necessary, MBS requires much less reagent by weight than conventional processes resulting in a waste with minimal volume increases. This significantly reduces storage, off-site transport and disposal costs.