The collection of any penalty under the provisions of this act shall not be construed as estopping the Commonwealth, or any district attorney or solicitor of a municipality, from proceeding in courts of law or equity to abate pollutions 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 the 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 in 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 to abate any pollution now or hereafter existing, or enforce common law or statutory rights.