Two projects are currently underway that will drastically change and improve how Juneau deals with its sewage. Sewage – any water that’s been used in washing, flushing or manufacturing – is also called wastewater. These improvements will reduce costs and could even result in Juneau’s wastewater treatment by-products having potential commercial value.
When it comes to wastewater, Juneau has come a long way in protecting the environment and public health. Prior to the city and borough consolidation in 1970, treatment of the area’s wastewater largely fell under the model, ‘The solution to pollution is dilution.’ Storm water and wastewater piping, which were mostly combined, went directly into adjacent water bodies. Juneau wasn’t alone in this method; most American cities, large and small, employed similar systems. Then, Congress passed the Clean Water Act in 1972. The federal government started providing grants and loans to collect and treat waste streams. In 1975, CBJ constructed a collection system for Douglas and Juneau, and provided treatment at the Thane Rock Dump site. Since then, CBJ’s collection system has greatly expanded with extensions throughout Lemon Creek, Mendenhall Valley, Auke Bay and North Douglas.
Ongoing street and utility improvements over the years have mostly separated CBJ’s storm and wastewater collections, reducing the load on the treatment plants during high rain events. The byproduct of treatment, appetizingly termed “sludge cake,” has long been the Achilles heel of wastewater treatment. In 1992, CBJ constructed an incinerator to burn the sludge, which lasted until 2010. Since then, CBJ has been shipping its sludge south in 60 brown containers at great cost and operational risk. But, this practice will soon end.
CBJ is undertaking two major projects to improve how wastewater is processed within the borough. The projects target both the front end of the treatment process and the final sludge produced. On the front end, CBJ is installing new mechanical screens at both the Juneau Douglas and Mendenhall treatment plants. These rotating screens are fitted with perforated plates that filter out debris and non‐biodegradable materials down to 3 mm in size. This will reduce wear on pumps and motors, improve the biological function of each treatment plant, and provide a more uniform solid waste stream for processing through a new biosolids dryer. The biosolids (a.k.a. “sludge”) dryer system is being constructed at the Mendenhall Wastewater Treatment Plant. Similar to other systems installed throughout the country, this system will dry the biosolids to a flaky dry condition. The dried biosolids can be utilized as fertilizer or as a potential supplementary fuel source. Once operational, the biosolids can be exported to agricultural areas or utilized locally.
While both projects are large in scale and cost, and will result in drastic improvements, Juneau residents have been and will still be able to – without thought or concern – turn on the tap, wash their hands and flush their toilets.
(This is written by the City Manager’s office and originally appeared in the December 1, 2017 Juneau Empire in a segment called, “City Corner”)