A wastewater treatment process integrates a tidal nitration system with a wastewater treatment lagoon. Raw effluent enters a lagoon having a persistent anoxic or anaerobic state and a long residence time to permit suspended solids to settle to the bottom, forming a blanket of sludge. Water above the sludge blanket is comparatively clearer than raw influent. Discharge from the clear water zone contains organic carbon, organic nitrogen, ammonia, and other nutrients. In the lagoon, complex carbohydrates and fats are broken down into simpler organic compounds by bacterial action, a substantial portion transformed to carbon dioxide by bacterial respiration, reducing BOD. Organic forms of nitrogen are transformed into ammonium ions by bacterial action. Adjacent to the lagoon is a sump that takes water from the clear zone to a tidal cell, and recycles water from the clear zone into the tidal cell, which then discharges back into the lagoon.