Phytoplankton

Abstract

This chapter on the phytoplankton of wastewater reservoirs is based on sixteen reservoirs which were investigated in detail in Israel (Dor et al. 1987a,b; Dor and Raber 1990; Abeliovich this volume; Dor unpublished results). The studied reservoirs are distributed all over the country and they differ considerably in the origin of their effluents which may be a mixture of domestic wastewater and floods, while others also receive manure or industrial wastes. Their volumes vary from 50 000 to 12 000 000 m3 and the depths from 5 to 14 m. Organic contents of the wastewater stored in the reservoirs (as BOD₅ filtrate) and total suspended solids (TSS) range widely: 4-160 mg 1^-1 and 6-150 mg l^-1 respectively. The most common type of reservoirs have a medium loading with BOD_5f = 30-60 mg l^-1. Ammonia (as N) and total nitrogen contents are around 15-20 and 30-40 mg l^-1 respectively. Total phosphate is usually around 5-7 mg l^”1. However, at the extremely high loads of dairy effluents, having in certain cases BOD₅ up to 10 000 mg 1^-1, ammonia content in the reservoir may reach 200 mg l^-1 and total phosphate 300-500 mg I^-1 (see Abeliovich this volume).