Design and Performance Evaluation of a Low-Cost Domestic Level Filter to Treat Kitchen Wastewater

The aspects of water security mainly govern by the availability and the quality of the water. As foreseen, use of portable fresh water for landscape irrigation can be a problem in the future. This research study was carried out with objectives of characterizing the raw kitchen wastewater (KWW), designing a domestic level filter for treating KWW and evaluating the removal efficiency of newly designed filter for reuse purpose. Four combinations of treatment systems were used namely in an order, sand and gravel layer, sand and bricks, sand and bricks with a coco peat layer and sand, bricks, coco peat and activated charcoal units for filtering. Raw kitchen wastewater samples were collected three times per day and made a composite sample by mixing equal proportion of each. Water quality parameters were measured before and after treatment of the KWW and compared with the Central Environmental Authority, Sri Lanka (CEA) standards. The average pH, Chemical Oxygen Demand (COD) and oil content in raw KWW was significantly higher than CEA standards. Based on results, raw KWW cannot be reuse for irrigation and it requires adequate treatment prior irrigation. The quality of filtrate from treatment system four resulted with the mean values of pH, electrical conductivity, temperature, total dissolved solids, COD and oil content and respectively quantitative figures were 7.2 ,0.65 mS cm^-1, 29.5°C, 230.1 mg L^-1, 365 mg L^-1 and 2.8 g L^-1 .The combination of sand, bricks, coco peat and activated charcoal filter filtrated effluent was within the CEA standards, which can be reuse for irrigation.