Nothing in this act shall be construed as estopping the Commonwealth, or any district attorney or solicitor of a local agency from proceeding in courts of law or equity to abate nuisances forbidden under this act, or abate nuisances under existing law. It is hereby declared to be the purpose of this act to provide additional and cumulative remedies to abate public health hazards and pollution of the waters of this Commonwealth, and nothing in this act contained shall in any way abridge or alter rights of action or remedies now or hereafter existing in equity, or under the common law or statutory law, criminal or civil, nor shall any provision of this act, or the granting of any permit under this act, or any act done by virtue of this act, be construed as estopping the Commonwealth, persons or municipalities, in the exercise of their rights under the common law or decisional law or in equity, from proceeding in courts of law or equity to suppress nuisances or public health hazards or to abate any pollution now or hereafter existing, or enforce common law or statutory rights.