Redox Tech provides its pH buffer as a stand-alone product based on market demand. Redox Tech has added this buffer to its carbon amendment for over a decade. Proper pH is crucial to sustain and enhance biological remediation in the subsurface. Organisms require an environment that supports their growth, reproduction, and overall survival. We have developed a water-soluble formula called NuBuff that can be applied in the subsurface by injection, soil mixing, or direct excavation application. NuBuff not only modifies and sustains pH within the desired range (~6-8), it also provides essential nutrients for micro-organisms.
NuBuff can be provided as a powder (typically in 5-gallon buckets, approximately 40 lbs dry weight) that is easily mixed with injection water on site, or it can be shipped as a liquid in concentration appropriate for direct application to the site. Sizes range from 5-gallon buckets to 330-gallon totes to tankers as desired.
NuBuff is typically applied as an aqueous-based fluid that is easy to inject and contains a suite of pH buffers and adjusters and biological nutrients that are combined and formulated based on site-specific parameters and goals. We use dipotassium phosphate, ammonium phosphate, sodium bicarbonate, and other carbonate products.
NuBuff has always been used in our ABC product. Like the other components of ABC, such as carbon substrates and micronutrients, the quantity and composition are formulated specifically to address each site’s needs and conditions.
The organisms commonly recognized to degrade contaminants are tolerant of a range of pH conditions, but as with most organisms, they prefer near-neutral pH. For example, the bacteria for complete dechlorination of PCE and its daughter products, DHC ethenogenes 195, prefer a pH between 6.8 and 7.5 but, similar to other neutrophiles, can thrive in pH between approximately 6 and 8. For petroleum-degrading bacteria, the optimal range is typically a bit wider (range from 6 to 9) with a larger assortment of capable organisms. Although contaminant-degrading extremophiles that can tolerate lower and higher pH exist, most remediation situations rely on neutrophiles. Maintaining a neutral pH also helps minimize the transport of other chemicals, such as dissolved metals.
The amount of buffer required depends upon several factors, such as contaminant load, groundwater flow rate, background pH, carbon substrate, etc. Redox Tech, as always, will assist with estimating your buffer needs.