Methemoglobinemia

Water Freedom System

Survive Global Water Shortages

Get Instant Access

The term ''methemoglobinemia'' or ''blue baby syndrome'' refers to the disease experienced by an infant who consumes groundwater contaminated with nitrate ions. When an infant consumes formulae made with groundwater contaminated with nitrate ions, the ions are easily converted to nitrite ions in the infant's digestive tract. The nitrite ions that enter the infant's circulatory system bond quickly to the iron in the hemoglobin or red blood cells (Figure 1.4).

Methemoglobinemia

^ red blood cell

Figure 1.4 Methemoglobinemia. If nitrate-contaminated groundwater is used as a potable or drinking water supply, the presence of nitrate ions represents a significant health concern for infants. Nitrate ions may be present in the groundwater due to the overuse of fertilizers, malfunction of septic tanks, or the discharge of high levels of nitrate ions in the effluent of wastewater treatment plants. When an infant consumes nitrate ions from potable water used to prepare baby formula, the nitrate ions are quickly reduced to nitrite ions in the infant's digestive tract. When the nitrite ions enter the infant's circulatory system, they bind quickly and tightly to the iron within the red blood cells or hemoglobin. Once bonded to the red blood cells, oxygen can no longer be transported in adequate quantities throughout the infant's body.

^ red blood cell

Figure 1.4 Methemoglobinemia. If nitrate-contaminated groundwater is used as a potable or drinking water supply, the presence of nitrate ions represents a significant health concern for infants. Nitrate ions may be present in the groundwater due to the overuse of fertilizers, malfunction of septic tanks, or the discharge of high levels of nitrate ions in the effluent of wastewater treatment plants. When an infant consumes nitrate ions from potable water used to prepare baby formula, the nitrate ions are quickly reduced to nitrite ions in the infant's digestive tract. When the nitrite ions enter the infant's circulatory system, they bind quickly and tightly to the iron within the red blood cells or hemoglobin. Once bonded to the red blood cells, oxygen can no longer be transported in adequate quantities throughout the infant's body.

The presence of nitrite ions on the iron prevents the hemoglobin from obtaining oxygen as it passes through the infant's lungs. The lack of oxygen throughout the infant's body causes the infant's skin to turn blue, thus the term ''blue baby syndrome.'' If insufficient oxygen is present in the infant's brain, paralysis or death may occur.

Methemoglobinemia usually is associated with rural communities where potable water is obtained from groundwater. Methemoglo-binemia has no warning sign, and although it can occur in adults, it occurs more rapidly in an infant's due to their lower body pH and lower body weight as compared to adults.

Although many activated sludge processes are required to nitrify in order to satisfy an ammonia discharge limit, often activated sludge processes that are not required to nitrify, do nitrify. As long as operational conditions are favorable for nitrification to occur, nitrification will occur.

If nitrification is not properly monitored and regulated, an unde-sired form of nitrification may occur. This undesired form of nitrification might result in increased operational costs, operational upset conditions, and violations of discharge requirements (Table 1.3). Because of increased water quality concerns, a nitrification requirement will play a greater role in the treatment of nitrogenous wastes in activated sludge processes.

Although many activated sludge processes are required to denitrify in order to satisfy a total nitrogen discharge limit, often activated sludge processes that are not required to denitrify, do denitrify. As long as operational conditions are favorable for denitrification to occur, denitrification will occur.

If denitrification is not properly monitored and regulated, unde-sired denitrification might result in increased operational costs, oper-

TABLE 1.3 Operational Problems Associated with an Undesired Form of Nitrification

Operation Problem

Description

Increased operating

Increased aeration demand to oxidize NHJ to NO3

costs

Increased chlorine demand to control filamentous growth

Increased chlorine demand to control coliform bacteria

Operational upset

Clumping of solids in secondary clarifiers due to

denitrification

Permit violation

Interference with effective control of coliform bacteria

TABLE 1.4 Operational Problems Associated with Undesired Denitrification

Operational Problem Description

Increased operating costs Increased use of metal salts/polymers to thicken and capture solids in clarifiers Operational upset Clumping of solids in secondary clarifiers due to denitrification

Permit violation Discharge of elevated level of total suspended solids

ational upset conditions, and violations of discharge requirements (Table 1.4). Because of increased water quality concerns, a denitrifi-cation requirement will play a greater role in the treatment of nitrogenous wastes in activated sludge processes.

Because many activated sludge processes nitrify and denitrify, a review of the microbiology of nitrification and denitrification is desirable for process control, troubleshooting, and cost-effective operation. A review begins with an overview of nitrogen, nitrogenous wastes or compounds, the activated sludge process, and the bacteria involved in the treatment of wastes.

Was this article helpful?

0 0
Growing Soilless

Growing Soilless

This is an easy-to-follow, step-by-step guide to growing organic, healthy vegetable, herbs and house plants without soil. Clearly illustrated with black and white line drawings, the book covers every aspect of home hydroponic gardening.

Get My Free Ebook


Post a comment