Makeup Water Treatment
Sheppard T. Powell Associates LLC (STPA) has considerable experience in planning, design, operation and evaluation of various types of makeup water treatment facilities. STPA authored for the Electric Power Research Institute (EPRI) the Guidelines for Makeup Water Treatment (GS-6699, 1990), the Revised Guidelines for Makeup Water Treatment (TR-113692, 1999) and the membrane filtration and Reverse Osmosis (RO) sections of the Guidelines for Makeup Water Treatment-Conventional Fossil and Heat Recovery Steam Generator Water/Steam Cycle Makeup (TR-1019635, 2010) for EPRI.
Water Requirements and Sources and Reuse Options
STPA has provided consultation for defining the quality and quantity of makeup water to power boilers, recovery boilers, HRSGs, cooling tower systems, service water systems, closed cooling water systems and open cooling water systems. Included in the quantity determination are the on-site water storage requirements. STPA has experience with surface water, groundwater, municipal water, wastewater and recycled water for raw water supply to a facility. STPA has evaluated reuse waters & water management options and constructed and reviewed water balances.
Based on the characteristics of the water supply and product water quality, a treatability study develops the unit processes required to treat the water supply. For new facilities, one may evaluate various water supplies or reuse waters (raw water, blowdown, treated wastewater, evaporator distillate). For existing facilities, a study can determine if a new treatment system is required or if modifications can utilize the existing water treatment system. STPA can provide the conceptual design for new or replacement systems. Also, the study may include biological control options.
Pretreatment: Clarification and Filtration
STPA has evaluated the design and operation and helped troubleshoot pretreatment systems for removing suspended solids, colloidal solids, organics, color, iron, manganese, and hardness (chemical softening). These have included filtration systems containing sand filters, gravity filters, pressurized filters, multimedia filters, carbon filters, micro-filters and ultra-filters.
Demineralization and Degasification
STPA has performed in-depth evaluations of the design, operation and troubleshooting of makeup demineralization systems using various forms of ion exchange (softening, organic traps, strong and weak cation and anion exchange, mixed bed), degasification (decarbonator or membrane degasifier), reverse osmosis (RO) membrane demineralization, and continuous electrodeionization (CEDI).
STPA has developed chemistry manuals with control limits and response procedures for pretreatment, filtration, demineralization and degasification equipment. STPA has conducted training seminars, treatment and surveillance audits and chemistry review of makeup water treatment systems for utility and industrial facilities.