The use of reed plants for wastewater treatment: the Iraq experience.

The use of plants, especially of species that grow naturally and under harsh environmental conditions, offers a simple and economic method of wastewater treatment. This method has been gaining wide popularity throughout the world over the last decades. Iraq is considered to be a country with environmental conditions favourable for the natural growth of many aquatic plants such as reed (Qassab). The root-zone method of treating wastewater is suitable for Iraq, e.g. because of its economy and the fact that such treatment does not need sophisticated mechanical or electrical equipment, or chemical materials. The most important aspect is that this method makes use of a weed, namely the reed. A mobile test tank for root-zone treatment stationed in the Rustamya sewage treatment plant and run for nearly 34 weeks. A total of 768 samples of the influent and effluent sewage were analysed. Average removal efficiencies for biological oxygen demand, suspended solids, chloride, phosphate and ammonia ranged from 92 to 82%, and chloride was removed with 13% efficiency. These results indicate that the root-zone method is adequate for the treatment of domestic sewage and can compete with conventional treatment methods whose average effluent concentrations for BOD5 and suspended solids are similar. A survey of water quality was conducted on a drainage ditch north-west of Baghdad to assess its natural purification process. The ditch that was chosen was infested with reed plants and other aquatic weeds. The role of the macrophytes was found to be essential in the process of self-purification of the water body. Results of the survey indicate that such ditches and streams could be used as disposal points for domestic sewage and industrial wastes. However, further assessment of their performance particularly for removal of suspended solids, pathogens, phosphate and nitrogen is necessary. The results indicate that reed beds may be suitable particularly for treatment of wastewater from small and remote towns and villages in Iraq.