tailieunhanh - Water Pollution Control - A Guide to the Use of Water Quality_3

Hệ thống này nhiễm cây lấy rễ và cây trồng thực vật phát triển gần mặt đất, nhiều hơn bất kỳ phương pháp khác, cho thấy nhiều công nhân lĩnh vực nội dung tác nhân gây bệnh của nước thải. Như vậy, với sự tôn trọng cho cả sức khỏe và nước, bảo tồn thủy lợi biên giới với nước thải không đạt yêu cầu. | Table analyses these factors in relation to four widely practised irrigation methods namely border furrow sprinkler and drip irrigation. A border as well as a basin or any flood irrigation system involves complete coverage of the soil surface with treated wastewater which is not normally an efficient method of irrigation. This system contaminates root crops and vegetable crops growing near the ground and more than any other method exposes field workers to the pathogen content of wastewater. Thus with respect to both health and water conservation border irrigation with wastewater is not satisfactory. Table Different levels of tools for public participation in the decision to reuse wastewater Purpose Tools Education and information Newspaper articles radio and TV programmes speeches and presentations field trips exhibits information depositories school programmes films brochures and newsletters reports letters conferences Review and reaction Briefings public meetings public hearings surveys and questionnaires question and answer columns advertised hotlines for telephone inquiries Interaction dialogue Workshops special task forces interviews advisory boards informal contacts study group discussions seminars Source Crook et al. 1992 Furrow irrigation does not wet the entire soil surface and can reduce crop contamination because plants are grown on ridges. Complete health protection cannot be guaranteed and the risk of contamination of farm workers is potentially medium to high depending on the degree of automation of the process. If the treated wastewater is transported through pipes and delivered into individual furrows by means of gated pipes the risk to irrigation workers is minimum. To avoid surface ponding of stagnant wastewater which may induce the development of disease vectors levelling of the land should be carried out carefully and appropriate land gradients should be provided. Sprinkler or spray irrigation methods are generally more efficient in .