Treatment of Domestic Sewage by Channels Constructed Wetland in New Countryside

[Objection] The aim was to study application of channels constructed wetland in treatment of domestic sewages in new countryside. [Method] Supported by construction of new rural areas project in China, we surveyed on new rural areas in Gannan, Jiangxi Province, summarized source, characteristics and treatment of domestic sewage in countryside, and designed channels constructed wetland for sewage treatment. [Result] The technique is proven effective in sewage treatment. After the technique was conducted for a trial run for four months, removal rates of COD, TP and TN averaged 73.07%, 73.25% and 72.36%, respectively. After contin- uous sampling for six times, effluent COD was analyzed 20-35 mg/L, TP was 0.60- 1.19 mg/L and TN was 6.88-11.21 mg/L, better than that of Standard 1B ruled by Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant. [Conclusion] Thanks for low investment, channels constructed wetland can be built by trans- formation of bottom land, proving a good way for treatment of diffuse pollution source and control of water non-point pollution.

Expansion of Financial Channel for the Construction of China's Highways

China’s highways started at a low level in facilities. In 1949, the total mileage of the whole coun-try’s highways was only 80,000 km, with a density of 0.001 km/sq km. Following the founding of New China, especially since the 1980s, great changes have taken place in the facilities of China’s highways. By the end of 1995, the

Ecological wetland paradigm drives water source improvement in the stream network of Yangtze River Delta

Jiaxing created a precedent using bypass riparian marshes to purify micro-polluted water sources in China.Pond-wetland complex with constructed root channel technology becomes a paradigm which can be analogized as"human-body wetland model"based on bionics or biomimetics.Heterogeneous plant-bed/ditch system with highly active land/water ecotone interfaces,especially meandering boundaries,breeds many biochemical reactions"living areas".Optimization of hydraulic regulation promotes redox environment alternations and wetland treatment efficiency.Here we reported a series of upgrades and performances in Guanjinggang wetland after the Shijiuyang prototype.Morphological reform of plant-bed/ditch system played a vital role.Spatially root channel zone was main force of wetland purification,and temporally the treatment effect was higher in low-temperature seasons indicating non-temperature dependent mechanisms worked.Water pollution comprehensive index improved steadily from IV to III,and comprehensive pollution load was reduced by ca.40%–60%.Comprehensive evaluation function value further showed the gradients purification effect of the upgraded wetland.Ecological wetlands ameliorated source water quality,and reduced drinking water treatment reagents,thereby bringing about economic benefits.Through wetlands operation,people can see how the micro-polluted surface water becomes clear and clean,so promoting a significant social benefit.As a viable component of urban green space,wetlands could beautify regional eco-environment,freshen the air,increase urban ecological taste,and enhance the eco-environmental protection publicity.Thus,the multifunctional service values and indirect benefits are substantial.Jiaxing ecological wetlands provide a typical paradigm for water pollution remediation in developing countries and plays a leading role in technology engineering radiation effect.

Performance of pond–wetland complexes as a preliminary processor of drinking water sources

Shijiuyang Constructed Wetland（110 hm^2） is a drinking water source treatment wetland with primary structural units of ponds and plant-bed/ditch systems. The wetland can process about 250,000 tonnes of source water in the Xincheng River every day and supplies raw water for Shijiuyang Drinking Water Plant. Daily data for 28 months indicated that the major water quality indexes of source water had been improved by one grade. The percentage increase for dissolved oxygen and the removal rates of ammonia nitrogen, iron and manganese were 73.63%, 38.86%, 35.64%, and 22.14% respectively. The treatment performance weight of ponds and plant-bed/ditch systems was roughly equal but they treated different pollutants preferentially. Most water quality indexes had better treatment efficacy with increasing temperature and inlet concentrations. These results revealed that the pond–wetland complexes exhibited strong buffering capacity for source water quality improvement. The treatment cost of Shijiuyang Drinking Water Plant was reduced by about 30.3%. Regional rainfall significantly determined the external river water levels and adversely deteriorated the inlet water quality, thus suggesting that the ＂hidden＂ diffuse pollution in the multitudinous stream branches as well as their catchments should be the controlling emphases for river source water protection in the future. The combination of pond and plant-bed/ditch systems provides a successful paradigm for drinking water source pretreatment. Three other drinking water source treatment wetlands with ponds and plant-bed/ditch systems are in operation or construction in the stream networks of the Yangtze River Delta and more people will be benefited.