Of 6634 registered industries in Pakistan, 1228 are considered to be highly polluting. The major industries include textile, pharmaceutical, chemicals (organic and inorganic), food industries, ceramics, steel, oil mil...Of 6634 registered industries in Pakistan, 1228 are considered to be highly polluting. The major industries include textile, pharmaceutical, chemicals (organic and inorganic), food industries, ceramics, steel, oil mills and leather tanning which spread all over four provinces, with the larger number located in Sindh and Punjab, with smaller number in North Western Frontier Province (NWFP) and Baluchistan. Hattar Industrial Estate extending over 700 acres located in Haripur district of NWFP is a new industrial estate, which has been developed with proper planning for management of industrial effluents. The major industries located in Hattar are ghee industry, chemical (sulfuric acid, synthetic fiber) industry, textile industry and pharmaceuticals industry. These industries, although developed with proper planning are discharging their effluents in the nearby natural drains and ulti- mately collected in a big drain near Wah. The farmers in the vicinity are using these effluents for growing vegetables and cereal crops due to shortage of water. In view of this discussion, there is a dire need to determine if these effluents are hazardous for soil and plant growth. So, effluents from different industries, sewage and normal tap water samples were collected and analysed for pH, electrical conductivity (EC), total soluble salts (TSS), biological oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen, cations and anions and heavy metals. The effluents of ghee and textile industries are highly alkaline. EC and TSS loads of ghee and textile industries are also above the National Environmental Quality Standards (NEQS), Pakistan. All the effluents had residual sodium carbonates (RSCs), carbonates and bicarbonates in amounts that cannot be used for irrigation. Total toxic metals load in all the effluents is also above the limit i.e. 2.0 mg/L. Copper in effluents of textile and sewage, manganese in ghee industry effluents and iron contents in all the effluents were higher than NEQS. BOD and COD values of all the industries are also above the NEQS. On the whole, these effluents cannot be used for irrigation without proper treatment otherwise that may cause toxicity to soil, plants and animals as well add to the problems of salinity and sododicity. Similarly, these effluents cannot be used for fish farming.展开更多
A field observation was carried out in the Changjiang (Yangtze) River Estuary from May 19 to 26, 2003. A total of 29 stations, including 2 anchored stations, were occupied through almost the whole salinity gradient. B...A field observation was carried out in the Changjiang (Yangtze) River Estuary from May 19 to 26, 2003. A total of 29 stations, including 2 anchored stations, were occupied through almost the whole salinity gradient. Based on the observation data, biogeochemistry of chemical oxygen demand (COD) was examined. Spatial distribution pattern of COD shows that it decreased downstream. The COD concentration varied generally within a narrow range of 1.24–1.60 mg/L in the zone around the river mouth, beyond which it decreased rapidly to 0.20 mg/L. In the mixed water zone, the fluctuation in COD was smaller at 2 m above the bottom layer than at the surface layer in 48 h. In the seawater zone, the 48-h fluctuation at the surface was the largest, followed by that of 5 m below the surface and 2 m above the bottom layers in a range of from 2.50 to 0.55 mg/L. Freshwater discharge was the dominant source of COD in the estuary. The average COD beyond the river mouth was 2.7 mg/L, which accorded with the Chinese seawater quality Grade I. Relationships between dissolved oxygen and biogeochemical parameters such as suspended particulate matter, dissolved organic matter and chlorophyll-a were also discussed.展开更多
To compare the treatment effects and the costs of coagulation/Fenton process and Fenton/coagulation process in leachate treatment,fresh and old leachates were respestively treated with these two techniques.The experim...To compare the treatment effects and the costs of coagulation/Fenton process and Fenton/coagulation process in leachate treatment,fresh and old leachates were respestively treated with these two techniques.The experimental results indicate that the highest chemical oxygen demand(COD)removal rate of Fenton reaction on leachate can be acquired under the conditions of pH=3.5,nH2O2/nFe2+=6,mH2O2/mCOD=3,and reaction time=4 h.Polyaluminium chloride(PAC)coagulation has the highest COD removal rate on leachate under the condition of mPAC/mCOD=0.6.Under the optimum reaction conditions,coagulation/Fenton and Fenton/coagulation processes were respestively adopted to treat raw leachate.The data also show that COD removal rate of coagulation/Fenton process on fresh and old leachates are 90.56% and 86.52% respectively and that of Fenton/coagulation process 89.99% and 85.99%,so there is no obvious difference.But the cost of coagulation/Fenton process for leachate treatment is RMB 62.6,lower than that of Fenton/coagulation process.Therefore,coagulation/Fenton process is more optimized than Fenton/coagulation process for leachate treatment.展开更多
Carbon monoxide （CO） intoxication is one of the most common types of poisoning in the modem world. To better tailor messages and communication needs to the public, a perception survey of CO and his risk was conducte...Carbon monoxide （CO） intoxication is one of the most common types of poisoning in the modem world. To better tailor messages and communication needs to the public, a perception survey of CO and his risk was conducted among the population of Rabat-Sale-Zemmour-Zaer. The authors included 400 people in this survey. The demographic characteristics of the respondents consisted of： 85.0% female, 92.9% adults, 29.7% had a high level of education, 49.6% unemployed, 89.5% were home owners and 53.9% lived in apartments. Water heaters were present in the homes of 91.0% of respondents and 6.5% of them used gas. Gas was used as fuel in 45.4% of cases. For water heaters, 20.8% had an exhaust duct, 9.9% were serviced regularly and 47.5% were installed in a well ventilated area. Regarding the media, television was the medium that allowed 73.4% of the CO to know, regardless of age, sex and level of education among the 94.3% of who ever heard of this deadly gas before the survey.展开更多
文摘Of 6634 registered industries in Pakistan, 1228 are considered to be highly polluting. The major industries include textile, pharmaceutical, chemicals (organic and inorganic), food industries, ceramics, steel, oil mills and leather tanning which spread all over four provinces, with the larger number located in Sindh and Punjab, with smaller number in North Western Frontier Province (NWFP) and Baluchistan. Hattar Industrial Estate extending over 700 acres located in Haripur district of NWFP is a new industrial estate, which has been developed with proper planning for management of industrial effluents. The major industries located in Hattar are ghee industry, chemical (sulfuric acid, synthetic fiber) industry, textile industry and pharmaceuticals industry. These industries, although developed with proper planning are discharging their effluents in the nearby natural drains and ulti- mately collected in a big drain near Wah. The farmers in the vicinity are using these effluents for growing vegetables and cereal crops due to shortage of water. In view of this discussion, there is a dire need to determine if these effluents are hazardous for soil and plant growth. So, effluents from different industries, sewage and normal tap water samples were collected and analysed for pH, electrical conductivity (EC), total soluble salts (TSS), biological oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen, cations and anions and heavy metals. The effluents of ghee and textile industries are highly alkaline. EC and TSS loads of ghee and textile industries are also above the National Environmental Quality Standards (NEQS), Pakistan. All the effluents had residual sodium carbonates (RSCs), carbonates and bicarbonates in amounts that cannot be used for irrigation. Total toxic metals load in all the effluents is also above the limit i.e. 2.0 mg/L. Copper in effluents of textile and sewage, manganese in ghee industry effluents and iron contents in all the effluents were higher than NEQS. BOD and COD values of all the industries are also above the NEQS. On the whole, these effluents cannot be used for irrigation without proper treatment otherwise that may cause toxicity to soil, plants and animals as well add to the problems of salinity and sododicity. Similarly, these effluents cannot be used for fish farming.
基金Supported by National Basic Research Program of China 973 plan (2007CB407305)the Qingdao Special Program for Leading Scientists (05-2-JC-90)the "100 Talents Project" of the Chinese Academy of Sciences
文摘A field observation was carried out in the Changjiang (Yangtze) River Estuary from May 19 to 26, 2003. A total of 29 stations, including 2 anchored stations, were occupied through almost the whole salinity gradient. Based on the observation data, biogeochemistry of chemical oxygen demand (COD) was examined. Spatial distribution pattern of COD shows that it decreased downstream. The COD concentration varied generally within a narrow range of 1.24–1.60 mg/L in the zone around the river mouth, beyond which it decreased rapidly to 0.20 mg/L. In the mixed water zone, the fluctuation in COD was smaller at 2 m above the bottom layer than at the surface layer in 48 h. In the seawater zone, the 48-h fluctuation at the surface was the largest, followed by that of 5 m below the surface and 2 m above the bottom layers in a range of from 2.50 to 0.55 mg/L. Freshwater discharge was the dominant source of COD in the estuary. The average COD beyond the river mouth was 2.7 mg/L, which accorded with the Chinese seawater quality Grade I. Relationships between dissolved oxygen and biogeochemical parameters such as suspended particulate matter, dissolved organic matter and chlorophyll-a were also discussed.
基金National Key Project of Water Pollution Control and Treatment Technology,China(No.2008ZX0720700902)
文摘To compare the treatment effects and the costs of coagulation/Fenton process and Fenton/coagulation process in leachate treatment,fresh and old leachates were respestively treated with these two techniques.The experimental results indicate that the highest chemical oxygen demand(COD)removal rate of Fenton reaction on leachate can be acquired under the conditions of pH=3.5,nH2O2/nFe2+=6,mH2O2/mCOD=3,and reaction time=4 h.Polyaluminium chloride(PAC)coagulation has the highest COD removal rate on leachate under the condition of mPAC/mCOD=0.6.Under the optimum reaction conditions,coagulation/Fenton and Fenton/coagulation processes were respestively adopted to treat raw leachate.The data also show that COD removal rate of coagulation/Fenton process on fresh and old leachates are 90.56% and 86.52% respectively and that of Fenton/coagulation process 89.99% and 85.99%,so there is no obvious difference.But the cost of coagulation/Fenton process for leachate treatment is RMB 62.6,lower than that of Fenton/coagulation process.Therefore,coagulation/Fenton process is more optimized than Fenton/coagulation process for leachate treatment.
文摘Carbon monoxide （CO） intoxication is one of the most common types of poisoning in the modem world. To better tailor messages and communication needs to the public, a perception survey of CO and his risk was conducted among the population of Rabat-Sale-Zemmour-Zaer. The authors included 400 people in this survey. The demographic characteristics of the respondents consisted of： 85.0% female, 92.9% adults, 29.7% had a high level of education, 49.6% unemployed, 89.5% were home owners and 53.9% lived in apartments. Water heaters were present in the homes of 91.0% of respondents and 6.5% of them used gas. Gas was used as fuel in 45.4% of cases. For water heaters, 20.8% had an exhaust duct, 9.9% were serviced regularly and 47.5% were installed in a well ventilated area. Regarding the media, television was the medium that allowed 73.4% of the CO to know, regardless of age, sex and level of education among the 94.3% of who ever heard of this deadly gas before the survey.
