Sewage ponds

The principal interest in photosynthetic bacteria for thek appHcabiUty to SCP production (Table 1) has been in Japan, where Jiodobacter capsulatus has been used to treat industrial wastes in sewage ponds (40,41). The product has been evaluated as a protein supplement in laying hen rations for egg production with acceptable results (40). 

Exercise 10.3 An investigation was ordered to find out whether a certain well was polluted by an adjacent sewage pond. The well contained 0.3 TU in 1973. What is your expert opinion ... 

A clear and concise description should be provided on relevant human activities in the study area. These should include dams, drainage channels, recharge installations, sewage ponds, industrial effluent ponds, fluid waste disposal installations, pumped well fields, and the nature and extent of agricultural activity, including irrigation schemes and the use of fertilizers (types, quantities) and pesticides (types, quantities). Part of the information may be abstracted from detailed maps, but most information has to be obtained directly from local authorities, farmers, and industry. 

Answer 10.3 The tritium can be used in this case both as an age indicator and as a tracer (0.3 TU reveals a pre-1952 effective age, and therefore no post-1952 water reached it from the sewage pond, which equilibrated to the prevailing atmospheric tritium value. The tritium concentration in the pond could be measured, or assumed from the local tritium curves. Suppose that the pond contained 300 TU, then its contribution to the well could be at most... 

The introduction of organic and inorganic nutrients into a stream affect P and R, but need not necessarily disturb the P-R balance. Sewage ponds and algae ponds are examples of systems with very high rates of... 

Table II. PRODUCTIVITIES OF MICROALGAL CULTURES IN HIGH-RATE SEWAGE PONDS ...

Waste stabilization ponds are shallow basins into which wastes are fed for biological decomposition. The chemical reactions involved are the same as those that occur in the other biological processes. Aeration is provided by the wind, and anaerobic digestion may also occur near the bottom of deeper ponds. The ponds are very commonly used for sewage treatment and dilute industrial wastes. Waste stabilization ponds are normally used as the final treatment step for effluents because they are not effieient enough to be used on their own. 

Effluent containing methyl parathion may not be discharged into lakes, streams, ponds, estuaries, oceans, or public waters unless the compound is specifically identified in a National Pollutant Discharge Elimination System (NPDES) permit. Moreover, discharge of effluent that contains methyl parathion is forbidden without prior notice to the sewage treatment plant authority (NPIRS 1986). 

Biological treatment Used in all sewage plants and many settling ponds. 

Biodegradation of diisopropyl methylphosphonate was not observed in acclimated cultures of bog water obtained from the RMA, even after the addition of extra carbon sources and an incubation period of up to 12 weeks (Spanggord et al. 1979). In addition, no biodegradation of diisopropyl methylphosphonate was observed in waters obtained from the Palo Alto sewage plant aeration tank or from a pond near Searsville Lake in Woodside, California. 

Land application of sewage sludge Leakage from sewage oxidation ponds... 

Behaviour of surfactants in soil after infiltration from septic systems and sewage-infiltration ponds and from surface waters... 

Direct infiltration of (treated) wastewater through sand beds and infiltration of sewage water from laundry ponds or septic systems are among the major contamination sources of surfactants into subsurface and groundwaters. Most studies published on this issue were released by research groups from the USA where these treatment techniques have found some use (Table 6.7.3). 

A field study was conducted by Larson et al. [31] to characterise the impact of effluent discharges on a sandy soil about 0.5 m below the surface. A 2.5 m thick unsaturated zone and a 3—4 m thick unconfined sand/gravel aquifer underlaid the tile field. LAS concentrations in the effluent plume decreased over a distance of 10 m from 10 000 to 30 xg L-1. A further object of study was a laundromat pond exposed to LAS-containing sewage for more than 25 years. A clay layer separated the natural pond from the vadose zone made up of porous sand. Measurements of LAS levels as a function of soil depth beneath the pond showed a rapid decrease from about 220 mg kg-1 at 30 cm to... 

The solubility of chlordecone in water is low (1--3 mg/L) and as with mirex, contamination is more likely to be associated with the particulate matter in the water rather than the water itself. Chlordecone was detected primarily in water samples collected in and around the production facility site in Hopewell, Virginia, and in adjacent waters of the James River estuary. Effluent from the Life Sciences Products Company facility contained 0.1 —1.0 mg/L (ppm) chlordecone, while water in holding ponds at the site contained 2--3 mg/L (ppm) chlordecone (Epstein 1978). Levels of chlordecone in river water in August 1975 ranged from not detectable (<50 ng/L [ppt]) in the York River and Swift Creek areas, to levels of 1--4 pg/L (ppb) in Bailey Creek which received direct effluent discharges from the Hopewell Sewage Treatment Plant. Water concentrations of up to 0.3 p g/L (ppb) were detected in the James River at the mouth of Bailey Creek and in the Appomattox... 

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