Table 7. --(Continued) 



— In the key to symbols below, capital letters stand for major types of treatment; lower case letters show 

 methods of treatment; sequence of letters indicate sequence of operations in the treatment processes. 



EA Extended aerat io n package plant that has units for aeration, settling, aerobic digestion, chlorination 

 and sludge holding. 



CS Contact stabilization package plant that has units for mixing, reaeration, settling chlorination an 

 aerobic digestion. 



A Aeration 

 a activated sludge, diffused 



air aeration 

 c Contact aerators 

 m activated sludge, mechanical 



aeration 



B Sludge beds 

 open 



C Settling tanks 



f Spirahoff 



i two story (Imhoff) 



m mechanical ly equipped 



p plain, hopper bottom or 



intermittently cleaning 



s septic tank 



D Digester , separate sludge 

 a aerobic 

 c with cover (fixed if not 



otherwise specified) 

 e gas used in engines (heat 



usually recovered) 

 f with floating cover 

 h gas used in heating 

 m stirring mechanism 



Population equivalent = mg./l. 



o open top 



p unheated 



r heated 



t stage digestion 



E Chlorination 



c with contact tank 



g by chlorine gas 



h by hypochlorite 



F Filters 



h high capacity 



2h high capacity, two stages 



r rotary distributor 



s intermittent sand 



t trickling 



G C r i t chambers 

 a aerated 

 h without continuous 



removal mechanism 

 m with continuous removal 



mechanism 

 p grit pocket at screen 



chamber 

 w separate grit washing 



device 



— Million liters per day = m.g.d 



— Winter (annual maximum). 



5-day B.O.D. x m.g.d. 

 x 3.79. 



8.34 



0.17 



Sludge storage tanks ( not 



second stage digestion units ) 

 open 



Sewage application to land 

 percolation beds 

 subsurface application 



Lagoons 



oxidation lagoons or ponds 



Ocean outfall sewer 



comminutor (screenings ground 

 in sewage stream) 



intermediate screens (1/8 to 

 1/2-inch openings) 



screenings ground in separate 

 grinder and returned to 

 sewage flow 



bar rack (1/2 to 2-inch open- 

 ings), hand cleaned 



bar rack (1/2 to 2-inch open- 

 ings), mechanically cleaned 



garbage ground at plant and 

 added to sewage flow 



Mechanical sludge dewatering 



centrifuge 



rotary vacuum filter 



Sludge disposal 

 used for fertilizer 

 used for fill 



of the 20 estuarine areas can be considered to 

 be strongly affected by pollution. They are the 

 Caloosahatchee River, Sarasota Bay system, 

 Hillsborough Bay, Old Tampa Bay, Boca Ciega 

 Bay, St. Joseph Bay, St. Andrew Bay, Escambia 

 Bay, Pensacola Bay, and Perdido Bay (plus the 

 Fenholloway River, not listed separately in 

 Table 1). Their combined area is 16 percent 

 of the west coast total, or 22 percent if Florida 

 Bay is excluded. 



Nationwide, some 62 percent of the estuarine 

 zone is damaged by pollution, 20 percent of it 

 heavily (U.S. Federal Water Pollution Control 

 Administration, 1969a — vol. 3, p. iv-413). Thus, 

 the extent of pollution in Florida's west coast 

 estuaries appears to be slightly less overall than 

 the extent of estuarine pollution nationwide. 



Figure 45 illustrates the distribution of clean- 

 water areas. They are Class II waters, suitable 

 for shellfishing; as such they pass the most 

 stringent bacteriological tests of any waters in 

 the state. 



Many waters are classified neither as polluted, 

 Fig. 44, nor as clean, Fig. 45. They exhibit the 

 intermediate condition designated Class III — for 



recreation and the propagation and management 

 of fish and wildlife. Most of Tampa Bay, coastal 

 waters from Boca Ciega Bay to Crystal River, 

 St. Joseph Bay, much of greater St. Andrew Bay 

 and parts of greater Pensacola Bay and Escam- 

 bia Bay are so designated. 



Details of pollution and its effects in specific 

 areas are provided in several useful publications, 

 some of which are mentioned below. Coliform 

 bacterial counts of sufficient magnitude to cause 

 concern were demonstrated in the Keys several 

 years ago (FSBH, 1963), a situation which, in 

 general, has improved little with time. Two re- 

 curring problems in Manatee County, the prolif- 

 eration of small domestic sewage treatment 

 plants and industrial wastes discharged to Bish- 

 op Harbor, were investigated by the Manatee 

 County Health Department (1967a,b). A com- 

 pilation of facts for regional planning in Sara- 

 sota, Manatee, Hillsborough, and Pinellas Coun- 

 ties was provided by Briley, Wild and Associates 

 (1967) in its inventory of water, sewer, and solid 

 waste systems. Effective pressure by citizen 

 groups and mass media have contributed to the 

 recent decision of Tampa voters to replace the 



109 



