Rapid Sand Filtration of Recycled Irrigation Water Controlled Pythium Root Rot of Poinsettia in Greenhouse

Pythium species incite crown and root rot and can be highly destructive to floriculture crops in greenhouses, especially when irrigation water is recycled. This study assessed the performance of rapid filtration of recycled irrigation water for controlling pythium root rot of poinsettia (Euphorbia pulcherrima) in greenhouses. Two greenhouse experiments investigated the effect of filter media type (sand and activated carbon), fungicide application (etridiazole), and pathogen inoculum source (infested growing media and infested irrigation water). Rapid sand filtration consistently controlled pythium root rot of poinsettia. Significant improvements in height, weight, root rot severity, and horticultural quality were observed for the plants in the sand filter treatment, compared with the inoculated control plants. However, the activated carbon filter removed essential nutrients from the irrigation water, resulting in plant nutrient deficiency and consequently leaf chlorosis, thus reducing plant weight, height, and horticultural quality. The etridiazole application did not completely prevent root infection by Pythium aphanidermatum, but plant weight, height, and horticultural quality were not negatively affected. P. aphanidermatum spread from infested growing media to healthy plants when irrigation water was recycled without filtration. Rapid sand filtration appears to have the potential to limit the spread of P. aphanidermatum that causes root rot of greenhouse floriculture crops.

Rapid Lava Sand Filtration for Decentralized Produced Water Treatment System in Old Oil Well Wonocolo

The Cepu Block Oil Field has been traditionally extracted since 2008 by the local community in Wonocolo. The oil well-produced gas and fluids consisted of crude oil and produced water. This oil production activity discharges high amounts of produced water. The fluids have been settled down in the sedimentation tank to gain the crude oil optimally. The remaining fluid called produced water has been discharged to the surface towards the river without any further treatment. This activity led to the deterioration of environmental quality. This study aimed to analyze the performance of produced water treatment by rapid sand filtration by measuring the degree of turbidity removal under the specific condition on a laboratory scale using lava sand. The sedimentation was conducted in 3 hours of retention time following the real field condition of the oil production process by community in one sample well. The rapid sand filtration was conducted by a fixed bed column method with 0.2 cm of grain size. The sedimentation process followed by the rapid sand filtration in produced water treatment yielded the high efficiency of turbidity removal reaching 98.65 %. The rapid sand filter also worked excellently in turbidity removal attaining 96.48 % of efficiency. These results confirmed that the sedimentation already done by the community followed by the rapid sand filtration is promising decentralized technology to be applied in a remote area such as Old Oil Wells Wonocolo regarding turbidity removal.

National survey of utilization of continuous water quality monitors in water supply systems in Japan

An investigation of the utilization of water quality monitors at water purification plants throughout Japan was conducted via questionnaire from August to October 2015. The number of types of monitors installed at more than one water purification plant was 34. Chlorine, high sensitivity turbidity, pH, and turbidity monitors were (highly) recommended for installation in four water purification processes (rapid sand filtration, chlorination only, slow sand filtration and membrane treatment), except for high sensitivity turbidity of chlorination only. The number of installations of the monitors recommended and their installation points were dependent upon the processes. Highly recommended points of turbidity were raw water and sedimentation points, which were set for (critical) control points in water safety plans. That of high sensitivity turbidity was the rapid sand filtration point for confirmation of Cryptosporidium control. Chlorine monitors were applied for automatic control, regardless of the water purification processes. Some interesting monitors, such as those for musty odor compounds and trihalomethane, were newly developed and utilized. The results of this study showed that water quality monitors were important for water quality management systems based on water safety plans in Japan.