Wastewater aboard watercraft has 2-3 times the strength of domestic effluents with BOD ranging from 100 to 1,000 mg/l, suspended solids varying from 200 to 1,100 mg/l, and coliform counts of the order of 10 to the 7th power - 10 to the 8th power/100ml. Holding tanks are probably the only technically and economically viable solution to control pollution from small watercraft. Recirculating toilets, an extension of the holding tank, permits 80-100 uses of the flushed medium before need for removal. Simple incinerating toilets are highly efficient, require minimum space, but pose a fire hazard and need large power input to operate. The macerator-chlorinator grinds up solids and does them with Cl before discharge; however, BOD or suspended solids levels are not reduced adequately. A variety of flow- through treatment devices can produce effluents equivalent to land-based secondary treatment. Shipboard biological treatment units have high susceptibility to shock loads and toxic chemicals, and have extensive space requirements. Low capital and operating costs are an advantage. Physicochemical treatment can produce effluents of high quality in a short time, are available in compact units, can handle any type of waste, and can be fully automated. Filtration, sedimentation, centrifugation, Cadsorption, ozonation, coagulation, and flocculation concepts have been used in these units. The chief disadvantage is the high capital and operating costs. Electrochemical processes, less costly, oxidize soluble organics and destroy pathogenic bacteria with sodium hypochlorite generated electrolytically from sodium chloride. Evaporator-incinerator units, which evaporate the liquid and burn the solids, can be expensive but leave no effluents. Wet oxidation relies on high temperatures (500 degress F) and high pressure (3,000 psi), which require expensive construction materials and large power input.

  • Corporate Authors:

    Southam Business Publications Limited

    1450 Don Mills Road
    Don Mills, ONo,   Canada 
  • Authors:
    • Bexzedits, S
    • Netzer, A
  • Publication Date: 1974-6

Media Info

  • Pagination: p. 33-34
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00129747
  • Record Type: Publication
  • Source Agency: Pollution Abstracts
  • Files: TRIS
  • Created Date: Mar 10 1976 12:00AM