Gray, N. F. Biology of wastewater treatment / N. F. Gray - 2nd ed. - London: Imperial College Press, 2004 - xviii, 1421 p. : ill. ; 23 cm. - Environmental Science and Management; 4 . Includes bibliographical references (p. 1219-1393) and index ISBN: 1860943284 Subjects--Topical Terms: Sewage--Purification--Biological treatmentSewage disposalBiotechnology