Effect of Shock Chromium(VI) Load on the Activated Sludge Process

Ülkü YETİŞ; Göksel DEMİRER; Hüseyin TEKİN

Makale detayları

Effect of Shock Chromium(VI) Load on the Activated Sludge Process

Yazarlar:

Ülkü YETİŞ | Göksel DEMİRER | Hüseyin TEKİN

Yayıncı:

TUBITAK

Dergi:

Turkish Journal of Engineering and Environmental Sciences 1998 Vol.22 Issue 6, pp.445-454

Belge Tipi:

Makale

Yayın Tarihi:

5/1998

Belge Dili:

Türkçe

Document ID (Org No.):

2000745364

Sıklık:

Üç Yıllık

eISSN:

1303-6157

pISSN:

1300-0160

Özet:

 

The effects of shock doses of Cr(VI) on activated sludge  process operating at a fixed dilution rate (0.12 h-1) without  recycle has been investigated.  Different levels of Cr(VI) (1.0, 2.0,  3.0, 5.0, 10.0, 25.0 and 50.0 mg/l) were suddenly dosed to activated  sludge units, operating at steady state with a synthetic wastewater  devoid of chromium and continued until a new steady state has been  reached.  The results have shown that Cr(VI) even at very low dosages  of 1.0 and 2.0 mg/l was toxic to the activated sludge process when  shock injection was applied.  The process performances observed at  these levels of Cr(VI) with acclimatised cultures in previous studies  have never been reached.  It has been observed that shock Cr(VI) doses  at low levels have immediately influenced the reactor biomass  concentration, but not the COD removal efficiency.  However, higher  levels of Cr(VI) (25.0 and 50.0 mg/l) caused immediate adverse  effects, and dramatic reductions in COD removal efficiency have been  observed.  The time elapsed to reach a new steady state after the  shock, has been observed to increase with increasing Cr(VI) dosages.   However, the shock injection of 50.0 mg/l Cr(VI) caused complete  destruction of microbial population and lead to oscillations in in  effluent COD concentration without a new steady state taking place  even after 1000 h (=120*hydraulic retention time).

 

The effects of shock doses of Cr(VI) on activated sludge  process operating at a fixed dilution rate (0.12 h-1) without  recycle has been investigated.  Different levels of Cr(VI) (1.0, 2.0,  3.0, 5.0, 10.0, 25.0 and 50.0 mg/l) were suddenly dosed to activated  sludge units, operating at steady state with a synthetic wastewater  devoid of chromium and continued until a new steady state has been  reached.  The results have shown that Cr(VI) even at very low dosages  of 1.0 and 2.0 mg/l was toxic to the activated sludge process when  shock injection was applied.  The process performances observed at  these levels of Cr(VI) with acclimatised cultures in previous studies  have never been reached.  It has been observed that shock Cr(VI) doses  at low levels have immediately influenced the reactor biomass  concentration, but not the COD removal efficiency.  However, higher  levels of Cr(VI) (25.0 and 50.0 mg/l) caused immediate adverse  effects, and dramatic reductions in COD removal efficiency have been  observed.  The time elapsed to reach a new steady state after the  shock, has been observed to increase with increasing Cr(VI) dosages.   However, the shock injection of 50.0 mg/l Cr(VI) caused complete  destruction of microbial population and lead to oscillations in in  effluent COD concentration without a new steady state taking place  even after 1000 h (=120*hydraulic retention time).

Makale detayları

Effect of Shock Chromium(VI) Load on the Activated Sludge Process

Yazarlar: Ülkü YETİŞ | Göksel DEMİRER | Hüseyin TEKİN

Yayıncı: TUBITAK

Dergi: Turkish Journal of Engineering and Environmental Sciences 1998 Vol.22 Issue 6, pp.445-454

Belge Tipi: Makale

Yayın Tarihi: 5/1998

Belge Dili: Türkçe

Document ID (Org No.): 2000745364

Sıklık: Üç Yıllık

eISSN: 1303-6157

pISSN: 1300-0160

Sayı

Yazarlar:

Ülkü YETİŞ | Göksel DEMİRER | Hüseyin TEKİN

Yayıncı:

TUBITAK

Dergi:

Turkish Journal of Engineering and Environmental Sciences 1998 Vol.22 Issue 6, pp.445-454

Belge Tipi:

Makale

Yayın Tarihi:

5/1998

Belge Dili:

Türkçe

Document ID (Org No.):

2000745364

Sıklık:

Üç Yıllık

eISSN:

1303-6157

pISSN:

1300-0160