Papers by Author: Ming Fen Niu

Abstract: This paper studied the removal effect of domestic sewage nitrogen and phosphorus during the start-up period of underground infiltration system. The experiment is conducted under the conditions of influent temperature 9~10°C, hydraulic loading 0.04m³·m^-2·d^-1, COD concentration 112.31~143.49mg / L, NH₄⁺-N 20.93~27.26mg / L and TP 2.12~2.86mg / L. The experimental results showed the removal rate of COD, NH₄⁺-N and TP was 80%, 98% and 95% respectively. In the start-up period, TN removal was not obviously for 34% removal rate. After treated the effluent nitrate nitrogen concentration was high, showing during the start-up period the nitrification was better than the denitrification. Lacking of carbon source and low temperature may account for this. To improve the conditions of the start-up period, promoting denitrification was the key to improve nitrogen removal rate by underground infiltration system.

Abstract: In this study, it was carried out by designing PH, soil fertilization content, humidity and mutagenic bacteria DX1 inoculation concentration of orthogonal experiment to research chlorpyrifos degradation rate in the soil, which was affected by mutagenic bacteria DX1 in the soil environment. SPSS software was taken visualized analysis and variance analysis to evaluate the impact of different levels of the test results, to determine the factors which had significant impact on the experimental results. It showed that the best environmental factors of chlorpyrifos degradation rate in soil were the pH 7, organic fertilizer content 5mg/kg, the soil moisture 70%, inoculation volume 50ml/kg. The pH value and inoculation volume had a significant impact on chlorpyrifos degradation rate in soil; the soil humidity had little effect and the organic fertilizer content had almost no effect.

Abstract: A2N is two-sludge system, by using the method that first bringing up the cultivation of denitrifying phosphorus removing bacteria (DPB) and nitrification biofilm separately then connecting them, which can start up A2N system successfully. Nitrification biofilm was cultivated in a sequencing batch reactor (SBR). After 30 days, NH4+-N effluent concentration steadily stayed below 0.5mg·L-1.In another SBR, the activated sludge for the enrichment of DPB is from the anaerobic tank, which was firstly operated under anaerobic/aerobic (A/O) condition. After 20 days, PAOs was successfully enriched. Then, the activated sludge was conducted under anaerobic/anoxic/aerobic (A/A/O) condition, maintaining the anaerobic time, gradually increased anoxic time and induced aerobic time. After 30 days DPB was successfully enriched, two phases totally take 50 days. The removal efficiency of total nitrogen and phosphorus are above 85 % and 95 %, so that A2N system was started up successfully.

Abstract: An experiment was conducted on a vegetable planting base in Damintun Town, Xinmin City, Liaoning Province to study the influence of different organic manure rate on nitrate distribution in vertical profile in a greenhouse soil over three continuous crop cultivations of cucumbers, beans and lettuces. The soil was treated with organic manure at five treatments. The results showed that the distribution characteristic was closely related with organic manure rate in the process of plant growth. After harvest of the cucumber and lettuce soil nitrate content of all layers was higher than before planting and the accumulation of nitrate was increased with the application rate of organic manure. When applied into the low amount of organic fertilizer (M1 and M2), no significant phenomenon of nitrate accumulation and leaching occurred. High amount of organic manure rate (M4) increased significantly (P<0.05), especially in 0~40cm soil layer. In the lower layer (60~120cm) of soil different degrees of nitrate leaching took place. The vertical distribution of nitrate before planting and harvest of beans showed that catch crops can effectively reduce the accumulation of nitrate in soil.

Abstract: The amount of soil inorganic N declined significantly with increasing of sampling depth and sampling time (P < 0.001). Compared with CK, application of untreated pig manure and slurry increased significantly the amount of soil inorganic N by 76.0% and 156.1%, respectively (P < 0.001). Compared with CK, application of untreated pig manure increased significantly the amount of soil NH4+-N by 33.7%, however, application of untreated pig slurry decreased remarkably that of soil NH4+-N by 7.4% (P < 0.001). Application of untreated pig manure and pig slurry increased significantly the amount of soil NO3--N by 86.9% and 198.0%, respectively compared with CK, (P < 0.001). Soil NO3--N accounted for the majority of soil inorganic N irrespective of fertilization treatment or sampling time, its percent were 80.13%, 84.27% and 92.63% in the CK, pig manure and pig slurry treatments, respectively. This result indicated that application of untreated pig manure and slurry increased significantly the amount of soil inorganic N, especially soil NO₃--N, which occurred the potential risk of nitrate pollution.

Abstract: An experiment of treating anaerobic fermented hogpen sewage by improved A2/O reactor was carried out to study the influence factors affect the pollution mater reducing rate during the course of combine domestication. After anaerobic fermented cultivation course of hogpen sewage by A2/O technics, thought the treatment system’s parameters included hydraulics reside time (HRT), deliquescent oxygen (DO), and reflux ration of nitrate solution (r) to study the system’s treatment effect. The experiment results indicated that the improved A2/O process starts with a smooth flow mode, the effluent COD, NH3-N removal were steady at about 90%, TN removal rate of up to 60% of available, TP removal rate of 85%, according to the test results, taking into account the energy consumption problem, the best conditions for the system: DO= 3 mg / L, HRT =24 h, nitration liquid reflux ratio 3.