IWRA Proceedings

AbstractWater scarcity and water pollution are some of the crucial issues in the world. One of the ways to reduce the impact of water scarcity and pollution is to expand water and wastewater reuse. This paper presents two case studies to quantify impacts on water environment and conservation for sustainability, such as (1) using a low-cost gravity-type drip irrigation system (LCDIS) for lettuce (Lactuca sativa) and tomato (Licopersicum esculentum) during two dry seasons; and (2) re-use of greywater (such as kitchen and laundry wastewater from households) for swamp cabbage (Ipomea aquatica).The case study 1 aimed to evaluate the performance of the low-cost gravity-type drip irrigation system under field conditions. Specifically, the study aimed to: a) determine the irrigation efficiency using gravity-type drip irrigation and furrow methods of irrigation; b) assess the growth and yield of lettuce and tomato as affected by different irrigation methods; and c) compare the economic feasibility of LCDIS with the farmer’s practice on lettuce and tomato. Field plot experiments were laid out separately for each crop to compare LCDIS and furrow irrigation method (as farmer’s practice). Agronomic parameters, irrigation performance indicators and crop yield components were gathered using standard methods. Results showed that using LCDIS revealed savings of 50% of water applied for lettuce and tomato with a yield increase up to 3 t ha-1 during the dry season as compared to the traditional furrow irrigation method used by farmers. Economic of scale suggest that LCDIS is feasible for large areas planted to high value crops. The case study 2 aimed to ascertain the effects of greywater such as kitchen waste water (KWW) and laundry waste water (LWW) from household on swamp cabbage in terms of the major chemical properties of KWW and LWW; effects of the level of concentration of KWW and LWW on the number of shoots, net growth and root length of swamp cabbage; and estimate the actual evapotranspiration of swamp cabbage. Swamp cabage plants were cultured in containers separately at different levels of KWW and LWW dillutions. The experiments were laid out in randomized complete block design under controlled environment. Water quality and agronomic parameters were gathered using standard procedures. Results of the study showed significant differences on some water quality and vine length, root length and net growth of swamp cabbage. After 6 weeks and thereafter, the plants reacted to the different dilutions where most plants wilted and severely injured as compared to plants cultured under lower dilution and tap water (as control). One hundred percent (100%) survival was observed under amended greywater (lower dilution) and tap water. The foregoing results showed that there is a need to amend greywater if reused for garden agriculture and industry in the near future. Effluent reuse for agriculture should be practiced with good integrated water management to reduce negative human health impacts that could be caused by uncontrolled use, so the effluent intended for reuse should be treated adequately and monitored to ensure that it is suitable for the intended use.