Evaluation of gradual hydroponic system for decentralized wastewater treatment and reuse in rural areas of Palestine

A pot experiment was conducted to evaluate the performance of a gradual multi-stage vertical flow hydroponic system as an option for decentralized wastewater treatment and reuse. The low cost of such option and the ease of its application make it feasible for rural areas where low cost decentralized options of wastewater treatment and reuse have a great potential in improving environmental and economic conditions in these areas. To evaluate the performance of such option, a five-stage vertical flow gradual hydroponic pot experiment was conducted in a greenhouse in the new campus of An-Najah National University. The experiment included five types of plants: two types of corn, barely, alfalfa, and sunflowers. Wastewater flow was applied through a drip system for the five types of plants. Wastewater was drained by gravity from one pot to the next through a gradual vertical flow hydroponic system. Quality of wastewater entering the first pot and leaving the last pot for each set of plants was monitored throughout the growing season. Results showed an over 90% removal efficiency of soluble organics and suspended solids, and about 60% removal efficiency of nitrogen through the system. The proposed gradual hydroponic treatment system was proved to be a successful alternative method to treat and reuse wastewater. Thus, gradual hydroponic systems could be successfully used as small decentralized wastewater treatment systems. This system could be used in producing crops with economic returns in Palestinian rural areas, where agriculture has a significant contribution in the income and employment of communities.