AUTO-PURIFICATION RESPONSE OF ONA RIVER, IBADAN TO INDUSTRIAL AND DOMESTIC EFFLUENT DISCHARGE

Abstract

This research study investigated the self purification capacity of Ona River due to wastewater effluent discharge from manufacturing industries and households in Oluyole area, Oyo state, Ibadan. Nigeria. Water samples were collected and flow rates measured at a length of 950 m along the river and depth of between 0.6 – 1.2 m. Twenty sampling stations were used (S1-S20) at 50 m intervals. Physico-chemical parameters (Chemical Oxygen Denab (COD), Dissolved Oxygen (DO), Total Soluble Solids (TSS), Total solids (TS),
Exchangeable cations (EC), and pH) were determined using standard procedures. Discharge was measured using current meter and measuring tape. Time of travel of river, de-oxygenation and re-aeration constants per day of river Ona were also calculated. Results showed maximum and minimum discharge of 15.43 and 2.57m3/s respectively along the stream. Upstream and point of wastewater discharge had BOD and DO values of 33.0, 7.31 and 914.0, 4.21 mg/L respectively