Protoporphyrinogen oxidase (protox) 저해형 제초제로 알려진 oxyfluorfen(OF), acifluorfen(AF), bifenox(BF) 및 oxadiazon(OD)에 대한 밀과 보리의 감수성 차이를 생리적 요인, 14 C-oxyfluorfen의 흡수 및 해부학적 변화를 온실 및in votro 상태에서 알아 보고자 하였다. 1. OF에 대한 밀과 보리의 품종간 I50 검정결과, 밀품종들의 I50 은 104 M의 진후를 보였고, 보리 품종들은 106 진후로 유의적인 차이를 보였다. 2. OF에 내성인 밀은 AF, BF 및 OD경엽처리에서 감수성인 보리보다 생체중 및 엽록소 함량 감소가 적었다. 그러나 이들 제초제들은 OF보다 밀과 보리간에 특이적인 반응차이는 보이지 않았다. 또한, 토양처리에서도 경엽처리와 유사한 경향을 보였다. 3. OF, AF, BF 및 OD의 100u M 처리에 따른 밀과 보리의 엽절편으로부터 시간별 전해질의 누출은 밀보다 보리에서 뚜렷하게 이루어졌다. 그러나 OF처리에서는 밀이 보리보다 광노출 10시간까지 차이를 보였으나 그 밖의 약제들은 광노출 후 20시간에서만 차이를 보였다. 4. 지질과산화 작용의 지표인 MDA의 생성량은 이들 약제를 105M농도로 처리시 밀보다 보리에서 많았다. 따라서 밀과 보리는 온실 및 in vitro 수준에서 Protox저해형 제초제에 대한 뚜렷한 감수성 차이를 보였다. 5. OF에 대하여 내성인 밀은 감수성 보리보다 14 C-OF의 흡수량이 적었고, 이러한 경향은 처리시간이 경과될수록 뚜렷하였다. 6. 밀은 OF 및 OD처리에 따른 잎표면의 구조적인 피해를 볼 수 없었으나, 보리는 납질의 손상이 컸다. 그러나 AF 및 BF처리에서는 밀과 보리간의 차이가 적었다. 또한, 4약제 처리에는 따른 밀은 해부학적 변화가 적었으나, 보리는 표피세포 및 엽육세포의 파괴로 엽신의 두께가 감소되는 경향을 보였다.

Stability of reactor and effect on biofilm characteristics were investigated by varying the hydraulic residence time in an inverse fluidized bed biofilm reactor(IFBBR). The SCOD removal efficiency was maintained above 90 % in the HRT range of 12hr to 2hr, but the TCOD removal efficiency was dropped down to 50 % because of biomass detachment from overgrown bioparticles. The reactor was stably operated up to the conditions of HRT of 2hr and F/M ratio of 4.5㎏COD/㎥/day, but above the range there was an abrupt increase of filamentous microorganisms. The optimum biofilm thickness and the biofilm dry density in this experiment were shown as 200 ㎛ and 0.08 g/㎤, respectively. The substrate removal rate of this system was found as 1st order because the biofilm was maintained slightly thin by the increased hydraulic loading rate.

Phosphorus and nitrogen loadings from the main tributaries into the Nakdong River were estimated by measuring phosphorus and nitrogen concentration in the main tributaries, Nakdong River(Kangjung), Kumho River, Heichun, Hwang River, Nam River, Milyang River, and Yangsanchun from May 1994 to October. Total phosphorus concentration of Kumho River was vary high, average 1.0 ㎎P/ℓ. The other rivers were the range 0.05∼0.15 ㎎P/ℓ. Total nitrogen concentration of Kumho River was vary high, average 6.27 ㎎N/ℓ. The other rivers were the range 1.5∼3.0 ㎎N/ℓ. The phosphorus loading from Kumho River, Nakdong River(Kangjung), Nam River, Milyang River, Hwang River, Yangsanchun, and Heichun were calculated to be 1,108, 603, 198, 57, 34, 23, and 21 tP/yr, respectively. Therefore, the loading from Kumho River accounted for 45 % of total loading, 2,042 tP/yr. The nitrogen loading from Nakdong River (Kangjung), Kumho River, Nam River, Milyang River, Hwang River, Heichun, and Yangsanchun were calculated to be 12,636, 7,411, 2,611, 1,523, 779, 608, and 391 tN/yr, respectively. Therefore, the loading from Nakdong River(Kangjung) and Kumho River accounted for 50 % and 30% of total loading, 25,959 tN/yr, respectively.

Batch experiments were performed to evaluate the effect of sludge acclimation and contact load on the behavior of phosphorus and organic substrates under anaerobic conditions. Four different sludges were acclimated in the sequencing batch reactors operated by intermittent aeration. All the experiments performed in a bench scale have shown the following results: 1. The unreleaseable phosphorus contents for four different sludges are the range of 16 ㎎ P/g SS to 24 ㎎ P/g SS, depending on the sludge acclimation conditions. 2. All the specific substrate uptake rates(SSUR) are expressed in the first order equation for releaseable phosphorus contents. The reaction rate coefficient, k, has the values of 4.0, 8.9, and 13.8 mg COD/㎎ P/hr, depending on the contact load and sludge species. 3. As reaction proceeds, the ratios of ΔP to - ΔCOD at high contact load are almost constant. in the range of 0.10 to 0.14, but at low contact load, they increase from 0.08 to 0.27.

The objective of this study was to examine and compare to transient response to quantitative and hydraulic shocks which produce equal changes in mass rate of organic feed in aerobic fixed-film process. The general experimental approach was to operate the system at several growth rates under steady-state(pre-shock) conditions, then to apply step changes during day 3 in dilution rate(hydraulic shock), or feed concentration(quantitative shock) at the same organic mass loading rate. Performance was assessed in both the transient state and the new steady-state (post-shock). Shock load of different type did not produced equivalent disruptions of effluent quality for equal increases on mass loading rate. Based on effluent concentrations, a hydraulic and a quantitative shock at the same mass loading caused equal increase in total effluent COD, but the increase was primarily a result of suspended solids the hydraulic shock and COD in the quantitative shock, The time which effluent COD came to peak values were about 32∼48 hours at the low organic loads and 52∼72 hours at the high organic loads, respectively. A quantitative shock produced a much greater increase in effluent COD than did a hydraulic shock at the same mass loading. Mean and peak values of effluent concentration were increased in 2.8∼4.2 times at low organic loading rate, 5.2∼6.6 times at the high organic loading rate respectively.

A number of experiments were conducted in order to investigate the organic removal efficiency and biomass characteristics according to the organic shock loading rate in a fluidized bed biofilm reactor. At the operation conditions of HRT, 8.44 hour, superficial upflow velocity, 0.9 ㎝/sec and temperature, 22±1 ℃, the removal efficiency of SCOD was founded to be 96.5, 92 and 90 % with the organic shock loading rate of 3.5, 10.8 and 33 kgCOD/㎥·day, respectively. Within the F/M ratio ranged 0.4 to 2.0 ㎏COD/㎏VSS·day, the SCOD removal efficiency was shown as 90% at F/M ratio of 2.0 ㎏COD/㎏VSS·day, but the TCOD removal efficiency was 72 % at F/M ratio of 1.8 kgCOD/kgVSS·day. The average biomass concentrations were 7800, 14950 and 27532 ㎎/l on the organic shock loading rate of 3.5, 10.8 and 33 ㎏COD/㎥·day, respectively. This result was agreed with the fact that more biomass could be produced at high concentration of substrate, but some biomass was detached at the onset of shock and easily acclimated at the shock condition.