Robert Tua Siregar, Hery Pandapotan Silitonga2, “Development Of Wastewater Treatment (IPAL) Communal Plant In Village Pardomuan Nauli In The District Laguboti District Toba Samosir With The Power Of Community Participation”, IJAST, vol. 29, no. 06, pp. 5672 - 5680, May 2020.