Water Environment & Technology (WE&T) is the premier magazine for the water quality field. WE&T provides information on what professionals demand: cutting-edge technologies, innovative solutions, operations and maintenance, regulatory and legislative impacts, and professional development.
This annual section examines the hot topics
facing the water sector today. This year the focus turns toward the gaining
advantages with real-time data and controls, debating climate change and
resiliency, and drawing a roadmap toward resource recovery.
Go beyond the conventional
Bowery Bay Waste Water Treatment Plant (New York) recently upgraded to a
biological nutrient removal (BNR) system to meet increasingly stricter limits
on effluent total nitrogen (TN). Optimizing the BNR process involved obtaining
control over primary effluent (PE) flow distribution to each of the four passes
of the step-feed secondary treatment system. Optimizing flow distribution to
each pass allowed for more efficient nitrification and denitrification by
balancing the conflicting drivers of maximizing solids retention time (SRT) for
nitrification while still providing adequate PE carbon for denitrification.
The City of Ottawa (Ontario, Canada) implemented
real-time control (RTC) to minimize combined sewer overflows (CSOs) to the
Ottawa River. The RTC system consists of flow control structures that are
operated automatically and dynamically in response to real-time sewer
conditions. This system has helped the city cost-effectively meet CSO
objectives by maximizing use of existing infrastructure.
Sharing the wealth
Desperate times call for desperate measures. But, in
the case of the Dublin San Ramon Services District in Dublin, Calif., desperate
times — specifically a dire, regional drought — also led to ingenuity and the
creation in June of the first recycled water giveaway program of its kind in
A water recycling facility in the California Bay
Area gives away water to help mitigate the drought
Coming in the next issue:
Adapt and prosper
water sector excels at creating standard operating procedures to accomplish
Herculean tasks from treating 100 million gallons of wastewater per day, to
removing pollutants from a combination of wastewater and stormwater, to
producing effluent cleaner than its receiving stream. Reaching these clear and
straightforward procedures, however, requires asking some hard questions about
the way things have been operating until now. This issue of WE&T presents
examples of how some different thinking and approaches can lead to gains in
program, project, and unit operation efficiency.
incentives converting skeptics or just preaching to the choir?” considers
whether incentives spur stormwater projects. Financial incentives include
grants, direct cost sharing, user fees, and coupons. Nonfinancial incentives
encompass awards and recognition, education and outreach, and giveaways. As
more communities dedicate public funds to stormwater management incentives,
they need best practices to ensure the money, time, and effort achieve results.
a more concrete note, “A clear winner” describes how a utility combined
thickening and grit removal in the world’s first large-scale primary dissolved
air floatation (DAF) clarifier. The Pima County Regional Wastewater Reclamation
Department in Tucson, Ariz., started this process at its new 105-million L/d
(32-mgd) Agua Nueva Water Reclamation Facility about a year ago. The new DAF
eliminated the need for separate solids thickening and grit removal while improving
oil and grease removal.
a year of operation, the primary DAF clarifiers have shown performance similar
to that of conventional primary clarification while combining waste activated
sludge and primary sludge thickening and grit removal in a single unit process.
The DAFs have removed between 50% and 75% of suspended material and between 30%
and 50% of influent chemical oxygen demand while reliably producing a thickened
conditions also spur adaption. For example, the Silicon Valley Advanced Water
Purification Center in San Jose, Calif., combines microfiltration, reverse
osmosis, and ultraviolet light to produce up to 30.3 ML/d (8 mgd) of purified
water. The Santa Clara Valley Water District, which manages the purification
center as part of an integrated water resources system that serves 1.8 million
residents and 200,000 commuters, faced challenges with growing water demand,
uncertainty in imported water supplies, recurring drought, regulatory
restrictions, and climate change. The purification center will help the
district provide at least 10% of demand with recycled water by 2025 by treating
secondary effluent to drinking water standards.