Nothing contained in this chapter shall be deemed to supersede, abrogate or repeal in any way any powers heretofore granted to any county in this state. This chapter shall be deemed to provide an additional method for the doing of the things authorized hereby, and shall be regarded as supplemental and additional to powers conferred by other laws, and shall not be regarded as in derogation of any powers now existing.
N.J.S. § 32:13A-20