Lany landfill, located in the Czech Republic, generates around 10 m3/d of leachate, heavily polluted with ammoniacal nitrogen, heavy metals and salts, which needs to be treated onsite in order to minimize their effect on the ecosystem and on human health. A sequencing batch reactor (SBR) was designed for ammoniacal nitrogen removal from the leachate and the economic feasibility and environmental impact of the designed SBR was assessed. From the cost-benefit analysis, capital expenditure (CAPEX) of 33,500 €/year and operational expenditure (OPEX) of 13,521 €/year were estimated. A shadow price concept tool was used to calculate the environmental benefit as 21,000 €/year. The net present value of the project was evaluated to be 19,528 € with an internal rate of return of 21.6%. For environmental assessment, triple bottom line (TBL) analysis on the existing practice of discharging the leachate to a nearby wastewater treatment plant and on-site treatment using SBR was performed. The total score for existing practice was calculated to be 55.1% while for on-site treatment it was 59.6%. Based on the results it was concluded that on-site treatment is both economically and environmentally feasible. A mitigation plan was also prepared for the impacts identified in the environmental assessment.