Citizens must be adversely affected by the violation and normally must give 60-days notice of the alleged violation to the alleged violator, State and EPA prior to filing suit.  40 CFR Part 254.  This notice and delay period are intended to allow the violator an opportunity to correct his violation and to give the EPA or State an opportunity to enforce compliance, thus making citizen enforcement unnecessary.

A citizen suit may not be commenced if the EPA or the State is already diligently prosecuting a civil action in a court to enforce compliance.

In a citizen suit, the court may grant an injunction, impose penalties, and award attorney fees and litigation costs to any prevailing or substantially prevailing party whenever the court determines such an award is appropriate.  Attorney fees will not be assessed against a citizen unless the court determines the suit is frivolous.
Solid Waste Disposal Act
Resource Conservation and Recovery Act Outline
The Solid Waste Disposal Act authorizes citizens to enforce compliance with any permit, standard, regulation, condition, requirement, prohibition, or order which has become effective pursuant to the Act and to compel the proper management of hazardous waste that may present an imminent and substantial endangerment to health or the environment.  42 USC ยง 6972.  Among  the  requirements  that may  be  enforced  by  citizens  are the criteria for solid waste disposal facilities in 40 CFR Part 257 and the criteria for municipal solid waste landfills in 40 CFR Part 258; and hazardous waste requirements.