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4 <br /> � �a�_�.vz;;�. �� , �:rrr,�t,..�.•?-' 4�' �� -�.w' kc:,-...�' a, -� - ?'4,.��. s-' ,�-°"� -s ,-tea•- -:a=. ,�-r..:�::�'.r�.. �ct�:. >:,... --i"S 4e=�7 ��v �'." <br />�,__. i' Vww . '!ya„y, -. -'�;.:hT y-' �-av��� - a—". � �" �.ss i ^v.:e � _A.x .2rsi -nr..-r...Ns .0� a-,ary ..,ay,. ,>7 _L.r., •-� �f r. -, <br /> - .t�` ,�.. � ,c��:�:µ� �ac�,.;: s:. _��r��W,:�-��5 �.z �..af_� .�.......,a �������t'�'°,,�..va, -� .`^.�i�`Y��;���'�� r,����-��°, c-�',*r�•a.r <br /> m <br /> x <br /> Problem Assessment Report December 5, 1989 <br /> USA Petroleum Station No. 65. Lodi, California AGS 87050-3 <br /> APPENDIX E <br /> EVALO,:TION OF REMEDIAL-ACTION OPTIONS <br /> Groundwater removal and aboveground treatment of the contaminated water can be done <br /> by several different methods. Treatment and disposal options include a) monitoring and <br /> continued assessment, b) air stripping, c) bioremediation, d) carbon adsorption, e) direct <br /> discharge, f) bioreactors, and g) waste hauling and offsite disposal. <br /> Monitoring and Continued Assessment <br /> Documentation of contaminant reduction and dispersion can be accomplished by <br /> { establishing a sampling schedule. Using the existing wells for ground-water sample <br /> collection and analyses will further assess the extent of contamination. After Possible <br /> sources of contamination have been removed, naturally occurring processes may reduce <br /> levels of contamination. This method is most effective when dealing with a limited extent <br /> of contamination in a semi-controlled environment. <br /> z A_ir-Strippine <br /> { An effective way of removing volatile and some semi-volatile compounds from ground water <br /> is to subject the contaminated water to a forced air stream. This is done by pumping the <br /> a contaminated water to the lop of a packed column where it is released to flow by gravity <br /> j against a countercurrent of air injected at the bottom of the column. As the air stream <br /> I reaches the top of the column, it removes the volatile compounds frorn the water. This air <br /> is then released directly into the atmosphere through air ports located on the top of the <br /> column or subjected to secondary treatment systems to meet emission requirements of the <br /> Air Pollution Control District. The treated water in turn flows from the bottom of the <br /> column to a predetermined discharge location. Secondary treatment systems for the treated' <br /> water can be installed to achieve the discharge requirements for acceptable levels 'of <br /> released contaminants. <br /> The purchase cost of the columns is rather inexpensive (compared to other alternatives). <br /> with low monthly operating .and maintenance costs. The most costly aspect of this <br /> technology is secondary air and water treatment systems and monitoring costs over the <br /> duration of the treatment process. Secondary treatment may be required to initially assess <br /> hydrocarbon levels in the discharged water. <br /> i <br /> ----€irorernediatton <br /> -_ ----- --- - ------._ ---- <br /> In js u bioremediation is a process through which the naturally occurring, contaminant-`r <br /> consuming bacteria are stimulated by the addition of nutrients and oxvgen. Bacterial <br /> 1 <br /> i . <br />